
<PAGE>   1

                                                                REDACTED VERSION

                                 EXHIBIT 10.28

                                       TO

                         TARGETED GENETICS CORPORATION

                                 AMENDMENT NO.1

                                       TO

                                    FORM S-1

                            TO BE FILED ON OR BEFORE

                                  MAY 30, 1996


"[*]" = confidential information omitted and filed separately with the
Securities and Exchange Commission pursuant to a request for confidential
treatment.
<PAGE>   2
                              DEVELOPMENT AGREEMENT

                  This Development Agreement ("Agreement") is entered into this
6th day of April, 1994, by and between Argus Pharmaceuticals, Inc., a Delaware
corporation ("Argus"), and RGene Therapeutics, Inc., a Delaware corporation
("RGene").

                  WHEREAS, concurrently with the execution of this Agreement,
Argus and RGene are entering into the Assignment Agreement and the Sublicense
Agreement referenced in Sections 1.1 and 1.2 below, whereby Argus is
transferring to RGene certain rights in the technology covered by the Assignment
Agreement and the Sublicense Agreement (the "Argus Technology"); and

                  WHEREAS, Argus and RGene desire to collaborate to conduct
certain research and experiments and to further the development of products that
may incorporate the Argus Technology, among others.

                  NOW, THEREFORE, it is hereby agreed as follows:

                  1. ASSIGNMENT/SUBLICENSE BY ARGUS

                       1.1 ASSIGNMENT OF MDA/ARGUS LICENSE

                  Concurrent with or prior to the execution of this Agreement,
Argus agrees that it will execute the Assignment Agreement in the form attached
hereto as Exhibit B (the "Assignment Agreement"), which Assignment Agreement
transfers to RGene certain rights of Argus under that certain Exclusive License
Agreement dated July 1, 1988 by and among Argus, The University of Texas System
Board of Regents and the University of Texas M.D. Anderson Cancer Center
("MDACC"), as amended ("MDA/Argus License Agreement"), relating to certain
technology rights and related patent applications invented by Dr. Gabriel
Lopez-Berestein at MDACC. Argus agrees that it will obtain MDACC's consent and,
if necessary, the consent of the Board of Regents of the University of Texas
System to the assignment of such rights by Argus, prior to or concurrent with
the other transactions contemplated by this Agreement.

                       1.2 SUBLICENSE OF UTRC LICENSE

                  Concurrent with or prior to the execution of this Agreement,
Argus agrees that it will execute that certain Sublicense Agreement in the form
attached hereto as Exhibit C (the "Sublicense Agreement"), which Sublicense
Agreement sublicenses to 


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<PAGE>   3
RGene all rights of Argus under that certain Agreement dated November 1, 1993 by
and between the University of Tennessee Research Corporation and Argus (the
"UTRC License Agreement"). Argus agrees that it will, if necessary, obtain the
consent of the University of Tennessee Research Corporation to the sublicense of
such rights by Argus, prior to or concurrent with the other transactions
contemplated by this Agreement.

                  2. DEVELOPMENT PROGRAM

                       2.1 GOALS

                  Commencing upon completion of the initial Work Plan and Budget
as set forth in Section 2.2(c), Argus and RGene agree to conduct the research
and development on products incorporating the Argus Technology ("Products"),
initially including those Products more particularly described in Exhibit A
hereto, according to the Work Plans and Budgets, with the goal of developing
commercially marketable Products in the shortest feasible period of time
consistent with the level of funding hereunder (the "Development Program").
Specifically, the initial goals of the Development Program will be to undertake
preclinical pharmaceutical development of the Products (including animal testing
and quality control testing to insure compliance with "good manufacturing
practices") and to file an investigational new drug application ("IND") with the
United States Food and Drug Administration ("FDA") regarding both Products;
provided, that the development of other products, that do not involve or relate
to the Argus Technology, will be negotiated by RGene and Argus in good faith on
a case by case basis. While the parties agree to use reasonable efforts to
achieve these goals, neither Argus nor RGene warrants or guarantees that their
efforts will result in the filing of an IND or marketable or approved Products
or that the goals specified in the Work Plan and Budget will be achieved within
the periods set forth herein.

                  2.2 PROGRAM ADMINISTRATION

                   (a) Project Representatives. The parties have each designated
a Project Representative to facilitate liaison between it and the other party,
oversee and review the progress of the Development Program, select indications
to pursue, determine the allocation of responsibilities between the parties for
conducting the Development Program, develop clinical trial protocols, manage the
clinical/regulatory process and discuss potential competition and other relevant
matters to assure rapid development and commercialization of the Products.

                   (b) Disagreements. All decisions made hereunder relating to
the Development Program shall require the approval of both Project
Representatives. The 



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Project Representatives shall attempt in good faith to reach consensus on all
matters. In the event of a disagreement between the Project Representatives, the
Project Representatives shall promptly present the disagreement to the chief
executive officers of the parties, who shall attempt resolution of the matter.
If such executives cannot promptly resolve such disagreement, then the dispute
shall be resolved under the arbitration provisions of Section 13.

                   (c) Work Plans and Budgets. Promptly after the date hereof,
the Project Representatives shall prepare and recommend to each party an initial
Work Plan and Budget for the remainder of 1994 which relates to the development
of the Products consistent with the goals set forth in Section 2.1 above. The
Work Plan and Budget shall be the plan and budget as approved by both parties in
writing. It is contemplated that Argus will provide substantially all of the
development services called for in the initial and any subsequent Work Plan and
Budget. Prior to October 1, of each year, the Project Representatives shall
prepare and recommend to each party a proposed Work Plan and Budget for the next
year. Each Work Plan and Budget adopted shall be signed by both parties. The
Project Representatives shall actively consult with one another throughout the
term of the Development Program so as to adjust the specific work performed
under the Work Plan and Budget to conform to evolving developments in technology
and the results of the development work performed. While minor adjustments to
the Work Plan and Budget may be made from time to time upon approval by the
Project Representatives, significant changes to the scope or direction of the
work and any changes in funding exceeding 15% of the total amount previously
budgeted in the Work Plan and Budget must be agreed to in writing by each party,
in the absence of which the most recently approved Work Plan and Budget shall
remain in effect.

                   (d) Progress Reports. Within 45 days following the end of
each calendar quarter, each Project Representative shall deliver to the other a
reasonably detailed written report which shall (i) describe the work performed
by it during the quarter on the Development Program and (ii) if appropriate,
recommend any revisions to the Work Plan and Budget that would improve the
progress of the Development Program.

                   (e) Meetings. The Project Representatives and other employees
or consultants or the parties responsible for management of the Development
Program shall meet at least once during each calendar quarter during the term of
the Development Program for the purpose of reviewing the status of the
Development Program including (i) relevant data, (ii) technical issues that have
arisen, (iii) issues of priority, (iv) the design and conduct of clinical trails
and anticipated regulatory filings, (v) budgets and expenditures, (vi)
competition and (vii) any other matters relevant to


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the development of the Products. Such meetings shall be at such times as may be
agreed to by the parties, and the location of such meetings shall alternate
between Argus facilities and RGene facilities, unless otherwise agreed by the
parties. The Project Representatives shall jointly prepare minutes summarizing
the matters reviewed and any actions taken at such meetings and shall distribute
such minutes to the parties within 14 days following each meeting.

                  2.3 PERFORMANCE OF SERVICES

                  Each party shall use all commercially reasonable efforts to
perform the development work assigned to it in a prudent and skillful manner in
accordance, in all material respects, with the Work Plan and Budget then in
effect and applicable laws. Each party shall furnish all labor, supervision,
facilities, supplies and materials necessary to perform the development work
assigned to it in accordance with the Work Plan and Budget then in effect.

                  2.4 REGULATORY FILINGS

                  The party assigned responsibility for any regulatory filings
with the FDA or any comparable foreign regulatory body shall make available to
the other party any materials it proposes to file for such party's review and
approval, which approval may not be unreasonably withheld or delayed. All
responses by regulatory bodies shall also be promptly disclosed to the other
party. In any case where responsibility for a regulatory filing is assigned to a
sublicensee, the applicable sublicense shall require the sublicense to afford
the parties hereto the same review, approval and comment rights with respect to
such regulatory filing as are set forth in this Section 2.4.

                  2.5 RECORDS AND DATA

                  Each party shall maintain records in sufficient detail and in
good scientific manner appropriate for patent and FDA purposes and so as to
properly reflect all work done and results achieved in the performance of the
Development Program. Such records, shall include books, records, reports,
research notes, charts, graphs, comments, computations, analyses, recordings,
photographs, computer programs and documentation thereof, computer information
storage means, samples of materials and other graphic or written data generated
in connection with the Development Program, including any data required to be
maintained pursuant to all applicable government regulations. Each party shall
provide the other the right to inspect records, and shall provide copies of all
requested records, to the extent reasonably related to the performance of the
other's obligations under this Agreement.

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                  2.6 VISIT OF FACILITIES

                  Representatives of each party may, upon reasonable notice and
at times reasonably acceptable to the other party, (a) visit the facilities
where the Development Program is being conducted and/or the facilities where the
other party manufactures any Product or active compound contained therein (or
has a Product or compound manufactured by a Third Party), (b) consult
informally, during such visits and by telephone, with personnel of the other
party performing work on the Development Program and (c) with the other party's
prior approval, which approval shall not be unreasonably withheld, visit the
sites of any Clinical Trials or other experiments being conducted by such other
party in connection with the Development Program, but only to the extent in each
case as such trials or other experiments relate to the Development Program. If
requested by the other party, Argus and RGene shall cause appropriate
individuals working on the Development Program to be available for meetings at
the location of the facilities where such individuals are employed at times
reasonably convenient to the party responding to such request.

                  2.7 EXCLUSIVITY

                  During the term of this Agreement, Argus agrees that it will
not engage in research and development relating to, and will not manufacture,
use or sell, any products relating to or utilizing in any way the Argus
Technology except as expressly provided herein. RGene acknowledges that Argus is
actively engaged in the development of pharmaceuticals for the treatment of
life-threatening infectious diseases and cancer. Except as set forth herein,
this Agreement is not intended and should not be construed to prevent or limit
Argus's ownership of or right to use its technology and patent rights in areas
outside the Argus Technology including without limitation the development of
pharmaceuticals involving gene therapy or antisense technology. Additionally,
Argus acknowledges that RGene is not limited in any way, subject to the terms
hereof, regarding the use of the Argus Technology, including without limitation
the sublicensing thereof to third parties.

                   2.8 ARGUS PROPRIETARY TECHNOLOGY

                  Argus and RGene recognize and agree that Argus has expertise
and proprietary technology not licensed to or owned by RGene pursuant to the
Assignment Agreement or Sublicense Agreement, including in the area of liposomal
drug delivery and manufacturing, which may be useful or necessary in the
development of the Products ("Argus Proprietary Technology"). RGene shall have a
non-exclusive royalty-free license to the Argus Proprietary Technology to the
extent useful or necessary (in RGene's good faith business judgment after
consultation with Argus) for the manufacture, use or sale of the Products
("Licensed Argus Proprietary Technology");


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<PAGE>   7
provided that RGene shall not be entitled to sublicense any such Licensed Argus
Proprietary Technology, directly or indirectly, without the express written
consent of Argus, which shall not unreasonably be withheld.

                   2.9 SUBCONTRACTS

                  Neither party may subcontract any portion of the development
work to be performed by it hereunder unless such subcontract is contemplated by
the Work Plan and Budget or otherwise approved in writing by the other party,
which approval shall not be unreasonably withheld or delayed. In the case of any
such approved subcontract, the payments to such subcontractor shall be included
in the calculation of Development Costs hereunder.

                   3. PAYMENTS AND FUNDING

                        3.1 FUNDING

                   RGene agrees that it shall bear all costs of funding the
costs set forth in Work Plans and Budgets regarding the Development Program. The
initial Work Plan and Budget is attached hereto as Exhibit 3.1.
 
                        3.2 ADDITIONAL CONSIDERATION FOR LICENSING

                  In further consideration of the assignment and sublicense made
by Argus to RGene as set forth in Article 1 hereof, RGene, effective as of the
date hereof, has issued to Argus 642,307 shares of the common stock of RGene,
all pursuant to the terms of that certain Stockholder Agreement by and between
RGene and Argus of even date herewith attached hereto as Exhibit 3.2.

                        3.3 REIMBURSEMENT OF DEVELOPMENT COSTS

                  Subject to the provisions of Section 2 and Section 3.1 hereof,
RGene agrees to compensate Argus for all Development Costs (defined below)
incurred by Argus in connection with the Development Program. For purposes
hereof, the term "Development Costs" means (i) the direct costs, fees and
out-of-pocket or other expenses incurred in the course of performing the work
under the Development Program plus (ii) an allocation of overhead costs on
internal research and development not to exceed 25% of the amounts set forth in
subparagraph (i) above and which shall be consistent with Argus' internal cost
accounting system.

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<PAGE>   8
                        3.4 REPORTS AND PAYMENTS

                  Within 60 days after the end of the first three calendar
quarters and within 90 days after the end of each calendar year, Argus shall
provide RGene with a reasonably detailed itemization of the Development Costs
incurred during the previous quarter for which it is entitled to reimbursement
from RGene. Within 30 days following receipt of such statements, RGene shall
reimburse Argus for such Development Costs for which Argus is entitled
reimbursement, subject to RGene's right to withhold reimbursement of any
disputed amounts pending resolution by the parties. RGene and Argus agree to
negotiate in good faith to resolve any such dispute. Argus shall keep and
maintain proper and complete records and books of account documenting all of its
Development Costs to be reimbursed or credited.

                        3.5 ROYALTIES

                  No royalties shall be payable by RGene to Argus regarding the
sale or commercial use of any Products or any other products developed from the
Argus Technology.

                        3.6 AUDIT RIGHTS

                  Each party shall permit the other party or its representatives
to have access, at its own expense, no more than once in each calendar year
during the term of this Agreement and twice during the three (3) calendar years
following the termination hereof, during regular business hours and upon
reasonable notice, to its records and books for the sole purpose of determining
the appropriateness of any amounts charged by such party hereunder or verifying
the amounts payable hereunder, if any. If such examination reveals that such
amounts have been overstated or understated for any calendar year, such
overpayment shall be promptly refunded or added to the remaining funding
obligation of such party hereunder or in the case of an underpayment, the party
shall promptly pay the amount of any underpayment; provided, that if such
examination was not conducted by an independent accountant, the party whose
records were examined shall have the right to engage an independent accountant
reasonably acceptable to the examining party to verify the results of such
examination. The fees and expenses of such accountant shall be paid by the party
alleging that the amounts charged or paid were incorrect, unless the error is
more than 10% of the actual amount due, in which case the party who made the
error shall pay all reasonable costs and expenses incurred by the investigating
party in the course of making such determination.

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                  4. OWNERSHIP; COMMERCIALIZATION

                        4.1 OWNERSHIP

                        (a) In connection with the Development Program, RGene
and Argus acknowledge and agree that new products or technology based on and/or
incorporating the Argus Technology, and improvements or modifications thereof,
may be developed (the "New Technology"), and that the New Technology will be
owned by RGene. Argus agrees to execute any assignments or other agreements
evidencing RGene's ownership of the New Technology as may be requested by RGene.

                        (b) Nothing herein shall give Argus any ownership or
commercialization rights with respect to any products, processes or other
technology rights which are developed under this Development Program or
otherwise owned by or licensed to RGene, except to the extent provided in
Sections 4.2 and 4.3 below.

                        (c) The terms of this Section 4.1 shall at all times be
subject to the provisions of Section 2.8 hereof, to the extent applicable.

                        4.2 MANUFACTURING

                  If RGene seeks to manufacture or contract with a third party
to manufacture a Product incorporating or utilizing the Argus Technology, RGene
hereby agrees to negotiate in good faith with Argus with respect to the
manufacture of such Product.

                        4.3 MARKETING

                  In the event that RGene desires to market or license to a
third party marketing rights to any Product incorporating or utilizing the Argus
Technology assigned to RGene under the Assignment Agreement, then RGene shall
send Argus notice of said intention. For a period of thirty (30) days after said
notice, Argus and RGene will enter into good faith negotiations regarding an
agreement whereby Argus would undertake the marketing effort of said Product.
Should the parties not execute an agreement prior to the conclusion of said
thirty (30) day period, RGene shall be entitled, in its sole discretion, to
market said Product or, within a twelve month period following the expiration of
such thirty (30) day period, license to a third party marketing rights to any
such Product; provided that the terms of any such license shall clearly be more
favorable to RGene than were last offered in writing by Argus, provided that
such offer by Argus remains outstanding during such twelve-month period. Upon
expiration of such twelve-month period, if no license has been entered into by
RGene with respect to said Product, RGene shall not license such Product 


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without complying with this Section 4.3. Argus shall have no other marketing 
rights to any of RGene's products except as set forth in this Section 4.3.

                        4.4 OTHER CONSIDERATIONS

                  Notwithstanding anything in Section 4.2 or 4.3 to the
contrary, any discussions between the parties with respect to marketing and/or
manufacturing of Products incorporating Argus Technology by Argus as opposed to
a third party, and any judgment as to the relative favorability to RGene of any
such transaction, shall take into account the terms of the proposed agreement
and the relative strengths of Argus and such third party, including sales force,
manufacturing capabilities, manufacturing capacity, marketing and economic
considerations and other relevant information.

                  5. PATENT PROSECUTION; INFRINGEMENT

                        5.1 PATENT PROSECUTION AND MAINTENANCE

                  RGene shall be responsible for filing, prosecuting and
maintaining the patents in the United States and foreign countries on all Argus
Technology licensed or transferred to RGene pursuant to the Assignment Agreement
and the Sublicense Agreement and RGene shall bear all costs associated
therewith. RGene shall have the sole right to file, prosecute and maintain the
patents in the United States and foreign countries on the New Technology, and
shall bear all costs associated therewith. Notwithstanding the foregoing, beyond
reasonable efforts, neither party assumes liability to the other for the
successful prosecution of any patent application.

                        5.2 THIRD PARTY CLAIM OF INFRINGEMENT

                  Each party shall give the other prompt notice of each claim or
allegation that the exercise of rights hereunder constitutes an infringement of
one or more patents or other rights of a third party. Each party shall use all
reasonable efforts to defend the parties against any such claim or allegation
with counsel of its own choice reasonably acceptable to such party. The costs of
such defense and any costs of settling or otherwise satisfying such claim shall
be borne by such party.

                  6. COMPLIANCE WITH LAWS

                  The parties acknowledge that the products and materials to be
developed pursuant to this Agreement are experimental, biological materials and
are not to be used in humans prior to appropriate regulatory approvals under any
circumstances. Each party agrees to comply with all laws and regulations for
handling and use thereof 



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and, if applicable, all export and import regulations of the United States of 
America and to provide the other party with evidence thereof upon request.

                  7. INDEMNIFICATION

                        7.1 MUTUAL RIGHT TO INDEMNIFICATION

                  Each party shall defend, indemnify and hold harmless the other
and its directors, officers, employees and agents from and against any and all
claims, liabilities, losses and expenses, including attorneys' fees, incurred by
or asserted against it or any of the foregoing arising out of the development,
testing, manufacture, handling or storage of any Product by such party,
including without limitation (i) any actual or alleged bodily injury, death or
property damage resulting from the use of any Product manufactured by such
party, (ii) any actual or alleged violation of law applicable to the
development, testing, manufacture, handling or storage of the Product by such
party and (iii) any product recall of Product manufactured by such party that is
ordered by a governmental agency or required by a confirmed Product failure as
reasonably determined by the parties, except as otherwise provided herein and
except to the extent that such liabilities, losses and expenses result from the
negligence or willful misconduct of a party, in which case the party who engaged
in such negligence or willful misconduct shall indemnify and hold harmless the
other party and its directors, officers, employees and agents.

                        7.2 PROCEDURE

                  Any person that intends to claim indemnification under this
Section 7 (an "Indemnitee") shall promptly notify the other party (the
"Indemnitor") of any claim, in respect of which the Indemnitee intends to claim
such indemnification, and the Indemnitor shall assume the defense thereof with
counsel mutually satisfactory to the parties; provided, however, that an
Indemnitee shall have the right to retain its own counsel, with the fees and
expenses to be paid by the Indemnitor, if representation of such Indemnitee by
the counsel retained by the Indemnitor would be inappropriate due to actual or
potential differing interests between such Indemnitee and any other party
represented by such counsel in such proceedings. The indemnity agreement in this
Section 7 shall not apply to amounts paid in settlement of any loss, claim,
liability or action if such settlement is effected without the consent of the
Indemnitor, which consent shall not be withheld unreasonably. The failure to
deliver notice to the Indemnitor within a reasonable time after the commencement
of any such action, if prejudicial to its ability to defend such action, shall
relieve such Indemnitor of any liability to the Indemnitee under this Section 7,
but not any liability that it may have to any Indemnitee otherwise than under
this Section 7. The Indemnitee and its employees and agents shall cooperate
fully with the Indemnitor and its legal 


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<PAGE>   12
representatives in the investigation of any action, claim or liability covered
by this indemnification. In the event that each party claims indemnity from the
other and one party is finally held liable to indemnify the other, the
Indemnitor shall additionally be liable to pay the reasonable legal costs and
attorneys' fees incurred by the Indemnitee in establishing its claim for
indemnity.

                        7.3 PRODUCT LIABILITY INSURANCE

                  Each party shall use all commercially reasonable efforts to
maintain product liability insurance with respect to its manufacture of the
Product hereunder. Such insurance shall be in such amounts and subject to such
deductibles as the parties may agree based upon standards prevailing in the
industry at the time such manufacturing commences.

                  8. TERM

                        8.1 INITIAL TERM

                  This Agreement shall have an initial term equal to three (3)
years from the initial date set out at the outset of this Agreement, unless
extended by the written consent of the parties or earlier terminated pursuant to
the provisions hereof.

                        8.2 EARLY TERMINATION

                  This Agreement may be terminated in advance of the expiration
of the term set forth in Section 8.1 above in accordance with the following
provisions:

                        (a) This Agreement may be terminated immediately by
either party in the event of bankruptcy, insolvency, receivership or compulsory
liquidation of the other party.

                        (b) In the event that any of the terms or conditions of
this Agreement or any of the Exhibits hereto are materially breached or
materially violated by one party (the "Defaulting Party") and are not corrected
within forty-five (45) days after written notice hereof has been given by the
nondefaulting party, the nondefaulting party shall have the right, in addition
to any other rights or remedies of action, to terminate this Agreement
immediately.

                        (c) This Agreement may be terminated by Argus if RGene
has not completed an equity financing with proceeds to RGene of at least $2.5
million by September 30, 1994.

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                  9. CONFIDENTIALITY

                        9.1 CONFIDENTIAL INFORMATION

                  Each of the parties hereby agrees that it will hold each
other's proprietary information, trade secrets, know-how, and related
confidential information, limited, however, to such information as is in written
form, or if disclosed orally, to a written memorandum delivered to the
nondisclosing party summarizing such orally disclosed confidential information
within 30 days of such disclosure ("Confidential Information"), in confidence
and will not disclose such Confidential Information to any third party without
the prior written consent of the other party, except as expressly provided in
this Agreement or as may be otherwise provided in any agreement which is an
Exhibit to this Agreement. Confidential Information shall not include any
information to the extent that the receiving party can show:

                        (a) that such information is publicly available or
otherwise generally known through no fault of its own;

                        (b) that such information was in its possession prior to
the date of disclosure;

                        (c) that it subsequently received such information from
a third party without restriction as to its disclosure or use;

                        (d) that it is authorized to disclose such information
by any subsequent written agreement between the parties hereto; or

                        (e) that it independently developed such information
without the benefit of the Confidential Information from such party.

                        9.2 NON-USE

                  Neither party shall use any of the Confidential Information
disclosed to it by the other party pursuant to the terms of this Agreement for
any purpose other than that which it has contemplated for herein, without the
consent of the other party hereto.

                        9.3 TERM

                  The confidentiality and non-use covenants contained in
Sections 9.1 and 9.2 above shall continue during the term of this Agreement and
for a period of five years thereafter.

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                        9.4 EMPLOYEES

                  Each party agrees that it will require each of its employees
who work on any Project contemplated by this Agreement to execute a
confidentiality and non-use agreement containing the above terms directly with
the other party to this Agreement, if requested.

                  10. SUCCESSORS AND ASSIGNS

                  The provisions of this Agreement shall be binding upon and
inure to the benefit of each of the parties hereto, their employees, officers,
directors and consultants, if any, together with their successors and assigns;
provided, however, that no right or obligation arising under this Agreement may
be transferred or assigned by either party without the prior written consent of
the other.

                  11. INDEPENDENT RELATIONSHIP

                  The parties agree that Argus will act as an independent
consultant or contractor to RGene and not as an employee, agent, partner or
joint venturer. Under no circumstances shall Argus, its agents, employees and
consultants, if any, be deemed to be agents or representatives of RGene, nor
will any of them have the right to enter into any contracts or commitments in
the name of RGene or otherwise bind or commit RGene.

                  12. PERSONS BOUND

                  Argus agrees to require its employees, consultants,
collaborators and agents, if any, that will be providing services under the
terms of this Agreement to acknowledge and agree to abide by all the terms of
Argus' obligations hereunder.

                  13. WARRANTY DISCLAIMERS

                  Argus makes no warranty or representation, either express or
implied, as to its findings, recommendations, specifications, or professional
advice for the services to be rendered hereunder except as follows:

                  (a) This Agreement does not conflict with any other agreement
to which Argus is bound;

                  (b) No other agreement exists which prevents Argus from
entering into this Agreement or performing the services to be provided
hereunder; and

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<PAGE>   15
                  (c) Argus agrees that it will not during the term of this
Agreement enter into any contract or agreement with any other party which would
abrogate any of its duties or rights hereunder, or compete with the development
efforts of RGene herein, without the prior written consent of RGene.

                  14. ARBITRATION

                  The parties agree that any dispute arising out of this
Agreement or its interpretation shall be submitted to binding arbitration to the
authority of an arbitrator selected by the parties and sanctioned by the
American Arbitration Association. If the parties cannot agree on an arbitrator,
they shall each select an arbitrator and the two arbitrators will select a third
arbitrator, with the decision of a majority of the arbitrators being binding.
The parties agree that the decision of the arbitrator shall be final and binding
and shall not be appealed. In the event of any litigation or arbitration between
the parties arising out of this Agreement, the prevailing party shall be
reimbursed for any and all reasonable attorneys' fees and court costs by the
losing party.

                  15. MISCELLANEOUS

                        15.1 GOVERNING LAW

                  This Agreement shall be governed by and construed in
accordance with the laws of the State of Texas, unless otherwise specially
agreed upon.

                        15.2 SEVERABILITY

                  If any part of this Agreement or any part of the Exhibits
hereto is deemed to be unlawful or invalid then that part shall be severed from
this Agreement or Exhibits, but the remaining parts and the Agreement or Exhibit
as a whole shall remain in effect and be binding upon both parties.

                        15.3 FORCE MAJEURE

                  Neither party hereto shall be liable to the other party for
the default of any obligation hereunder due to any cause which is beyond such
party's reasonable control, including, but not limited to, acts of God,
compliance with laws and orders, riot, fires, explosions, shipwrecks, epidemics,
and the like.

                        15.4 WAIVER AND AMENDMENTS

                  A breach of the terms or conditions of this Agreement may only
be waived in writing. No waiver of any breach of the terms and conditions of
this Agreement to be 


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<PAGE>   16
performed by the other party shall be construed as a waiver of any subsequent
breach, whether of the same, or any other, terms and conditions hereof. No
amendment to this Agreement shall be effective for any purpose unless in writing
and signed by an authorized officer of each party.

                        15.5 ENTIRE AGREEMENT

                  This Agreement and the Exhibits hereto constitute the entire
agreement and understanding between the parties and supersede and cancel all
previous negotiations, representations, undertakings, understandings and
agreements which have previously been made between the parties with respect to
the subject matter of this Agreement and the Exhibits.

                        15.6 NOTICES

                  All notices required or contemplated by this Agreement from
any party shall be in writing and shall be delivered either (a) by personal
delivery, (b) by regular mail, postage prepaid, (c) by electronic transmission,
confirmed by mail, postage prepaid, or (d) by overnight delivery service which
takes receipt of delivery. All notices delivered by mail or electronic
transmission shall be addressed to the party at its address set forth in this
Agreement, which address may be changed from time to time by notice delivered in
accordance with this Section 15.6. The effective date of any notice delivered in
accordance with this Section 15.6 shall be (a) the date of personal delivery,
(b) the third day after the date of mailing, or (c) the second business day
after electronic transmission.

                        15.7 COUNTERPARTS

                  This Agreement may be executed in one or more counterparts,
each of which shall be deemed an original, but all of which, taken together,
shall constitute one instrument.

                        15.8 EXPENSES

                  Each party agrees that it shall be liable for its own legal
fees and other expenses incurred by it in the negotiation of this Agreement, and
shall not be entitled to reimbursement by the other for such expenses either
directly or through the provisions of this Agreement.

                        15.9 RELATIONSHIP OF THE PARTIES

                  The parties agree that each is acting as an independent
contractor with respect to the other and nothing contained in this Agreement is
intended, or is to be construed, 


                                      -15-
<PAGE>   17
to constitute RGene and Argus as partners or joint venturers or Argus as an
agent of RGene. Neither party hereto shall have any express or implied right or
authority to assume or create any obligations on behalf of or in the name of the
other party or to bind the other party to any contract, agreement or
undertaking.

                                    ARGUS PHARMACEUTICALS, INC.

                                    By: /s/ D.M. LEECH
                                        ------------------------------------
                                    Name:  D.M. LEECH
                                          ----------------------------------
                                    Title:  President/CEO
                                           ---------------------------------
                                           3400 Research Forest Drive
                                           The Woodlands, Texas  77381

                                    RGENE THERAPEUTICS, INC.

                                    By:  /s/ MARTIN P. SUTTER
                                         -----------------------------------
                                    Name:  MARTIN P. SUTTER
                                          ----------------------------------
                                    Title:  Chairman
                                           ---------------------------------
                                           2170 Buckthorne Place, Suite 170
                                           The Woodlands, Texas  77380


                                      -16-
<PAGE>   18
                                    EXHIBIT A

                                   "PRODUCTS"

                  (a) An in vivo gene therapy product (EIA) treating ovarian
and/or breast cancer relating to the technology covered by the UTRC License
Agreement and the technology covered by the Patent and Technology License
Agreement between MDACC and RGene effective March 1, 1994; and

                  (b) An anti-sense product treating chronic myelogenous
leukemia (CML) relating to the technology covered by the Assignment Agreement.
<PAGE>   19
                                                                       Exhibit B

                            ASSIGNMENT AND ASSUMPTION

                  THIS ASSIGNMENT AND ASSUMPTION AGREEMENT ("Agreement") is
entered into this 6th day of April, 1994, by and between Argus Pharmaceuticals,
Inc., a Delaware corporation ("Argus"), and RGene Therapeutics, Inc., a Delaware
corporation ("RGene").

                  WHEREAS, Argus is the exclusive licensee of certain Technology
under that certain Exclusive License Agreement, dated July 1, 1988 by and among
Argus, the University of Texas Board of Regents and the University of Texas M.D.
Anderson Cancer Center, as amended ("Exclusive License Agreement");

                  WHEREAS, in exchange for the issuance of shares in RGene under
that certain Stockholder Agreement dated April 6, 1994 by and between Argus and
RGene, Argus wishes to assign to RGene its rights and obligations with respect
to the Technology licensed the Exclusive License Agreement; and

                  WHEREAS, RGene is desirous of obtaining the entire right and
interest of Argus in and to the Exclusive License Agreement as it relates to the
Technology and assume the obligations of Argus therefor, all pursuant to the
terms and conditions set forth below.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt of which is hereby acknowledged, the parties agree as follows:

I.                ASSIGNMENT

                  1.1 Argus hereby assigns to RGene, its successors and assigns,
all of the right, title and interest of Argus in and to the Exclusive License
Agreement to the extent and only to the extent that the Exclusive License
Agreement relates to the Invention identified in Amendment No. 3 to the
Exclusive License Agreement.

                  1.2 By its acceptance of this Assignment, RGene hereby accepts
all of the benefits and assumes all of the obligations of Argus under the
Exclusive License Agreement to the extent the Exclusive License Agreement
relates to the Invention identified in Amendment No. 3 thereto, including but
not limited to all costs and fees relating to the filing and prosecuting of
patent applications on the Invention and the payment of royalties and other
payments required by the Exclusive License Agreement to the extent the Exclusive
License Agreement relates to the Invention identified in Amendment No. 3
thereto.

                  1.3 Argus agrees to execute such further instruments as RGene
reasonably requests to secure or perfect in RGene the full benefit of the
Assignment set forth herein.
<PAGE>   20
II.               NEGATION OF WARRANTIES

                  2.1 Argus makes no representation or warranty (a) that any
patent application on the Technology will ultimately issue as a patent, (b) that
any patent application which issues into a patent is valid and enforceable, (c)
that the use of the Technology in the manufacture, use or sale of any product
will be free from infringement of patents of third parties, or (d) as to the
safety, reliability, or efficacy of the Technology which may ultimately be
incorporated in any product.

                  2.2 Argus makes no representations, extends no warranties of
any kind, either express or implied, and assumes no responsibilities whatever
with respect to the manufacture, use, or sale, or other disposition of any
products incorporating the Technology.

III.              MISCELLANEOUS

                  3.1 The execution of this Agreement by the University of Texas
Board of Regents and the University of Texas M.D. Anderson Cancer Center, as the
licensor of the Technology, is for the purpose of indicating their approval of
the provisions of this Agreement.

                  3.2 It is understood that this Assignment contains the entire
agreement between the parties relating to the subject matter of this Agreement.

                  3.3 This Assignment is deemed to have been made in the State
of Texas and shall be interpreted and construed in accordance with the laws of
the State of Texas.

                  IN WITNESS WHEREOF, signifying their acceptance of and
agreement to be bound by the terms and conditions of this Agreement, the
signatures of the parties are affixed hereto.

RGENE THERAPEUTICS, INC.                         ARGUS PHARMACEUTICALS, INC.

By:     /s/ MARTIN P. SUTTER            By:      /s/ DAVID M. LEECH
   ----------------------------            --------------------------------
Name:   Martin P. Sutter                Name:    David M. Leech
     --------------------------              ------------------------------
Title:  Chairman                        Title:   President and CEO
      -------------------------              ------------------------------
Date:   4-5-94                          Date:
     --------------------------              ------------------------------


                                      -2-
<PAGE>   21
THE UNIVERSITY OF TEXAS                    BOARD OF REGENTS OF THE 
M.D. ANDERSON CANCER CENTER                UNIVERSITY OF TEXAS SYSTEM

                                           

By:      /s/ DAVID J. BACHRACH             By:     /s/ THOMAS G. RICKS
    ----------------------------------         ------------------------------
Name:    David J. Bachrach                 Name:   Thomas G. Ricks
Title:   Executive Vice President for      Title:  Vice Chancellor for Asset
         Administration and Finance                Management
Date:    3-25-94                           Date:
      --------------------------------           ----------------------------

APPROVED AS TO CONTENT                     APPROVED AS TO FORM

By:      /s/ WILLIAM J. DOTY               By:     /s/ DUDLEY R. DOBIE, JR.
   ----------------------------------         ---------------------------------
Name:    William J. Doty                   Name:   Dudley R. Dobie, Jr.
Title:   Director, Technology              Title:  Manager, Intellectual 
            Development                            Property
Date:    3/22/94                           Date:
     --------------------------------            ------------------------------



                                      -3-
<PAGE>   22
                                                                       EXHIBIT C

                              SUBLICENSE AGREEMENT

                  This Sublicense Agreement ("Sublicense"), effective the 6th
day of April, 1994, ("Effective Date") is entered into by and between Argus
Pharmaceuticals, Inc., a Delaware corporation ("Argus"), and RGene Therapeutics,
Inc., a Delaware corporation ("RGene").

                                   WITNESSETH:

                  WHEREAS, the University of Tennessee Research Corporation
("UTRC") and McMaster University ("McMaster") executed and entered into an
agreement effective May 25, 1992 whereby UTRC received the exclusive right to
commercialize certain Technology including the right to grant licenses to third
parties;

                  WHEREAS, Argus is the licensee of that certain Technology
pursuant to an Agreement dated November 1, 1993 by and between UTRC and Argus
(the "UTRC License Agreement");

                  WHEREAS, in exchange for the issuance of shares in RGene under
that certain Stockholder Agreement dated April 6, 1994 by and between Argus and
RGene ("Stockholder Agreement"), Argus is willing to grant RGene an exclusive
sublicense to the Technology licensed under the UTRC License Agreement; and

                  WHEREAS, RGene is desirous of obtaining an exclusive
sublicense of the Technology pursuant to the terms and conditions set forth
below.

                  NOW, THEREFORE, for good and valuable consideration, the
receipt of which is hereby acknowledged, the parties agree as follows:

I.                DEFINITIONS

                  1.1 "Technology" shall mean the technology defined as
Technology in the UTRC License Agreement.

                  1.2 "Licensed Patent Rights" shall mean the U.S. and foreign
patents and applications defined as Licensed Patent Rights in the UTRC License
Agreement.

                  1.3 "Licensed Product" shall mean the products or compositions
defined as a Licensed Product in the UTRC License Agreement.
<PAGE>   23
                  1.4 "Licensed Fields" shall mean the applications of the
Technology and the Licensed Patent Rights defined as Licensed Fields in the UTRC
License Agreement.

                  1.5 "Excluded Fields" shall mean those applications and fields
excluded or reserved from the license defined as Excluded Fields in the UTRC
License Agreement.

                  1.6 "Argus Licensed Rights" shall mean and only include those
rights licensed to Argus under the UTRC License Agreement and shall specifically
exclude (for purposes of this Sublicense only and without affecting any other
agreement between Argus and RGene) any other proprietary rights owned or
licensed by Argus.

II.               SUBLICENSE

                  2.1 Subject to all the terms and conditions of this Sublicense
and the UTRC License Agreement, Argus hereby grants to RGene a worldwide,
exclusive sublicense under all the Argus Licensed Rights to fully exploit and
commercialize the Technology in the Licensed Fields granted to Argus under the
UTRC License Agreement subject to the Excluded Fields and any other reservations
or limitations set forth in the UTRC License Agreement.

                  2.2 RGene agrees that it will not utilize the Technology or
practice under the Licensed Patent Rights for any purpose other than that
encompassed by the Sublicense granted herein.

                  2.3 As the exclusive sublicensee of Argus, RGene hereby
accepts all the benefits and assumes all of the obligations of Argus under the
UTRC License Agreement and agrees to be bound by all terms and conditions of the
UTRC License Agreement on behalf of Argus and as sublicensee under the UTRC
License Agreement in each case subject to the terms and conditions set forth
herein.

                  2.4 Argus agrees not to utilize the Technology or practice
under the Licensed Patent Rights for any purpose other than with the prior
written agreement of RGene.

                  2.5 RGene agrees that it will comply with the terms of Section
2.6 of the UTRC License Agreement.

                  2.6 RGene shall use its best efforts to bring one or more
Licensed Products to market in each of the Licensed Fields.

                  2.7 Argus and RGene agree, and UTRC acknowledges, that RGene
is an Associate Sublicensee under the UTRC License Agreement

                                      -2-
<PAGE>   24
III.              PAYMENTS

                  3.1 The rights and licenses granted by RGene pursuant to
Article II shall be non royalty bearing to Argus and no payments shall be
required by RGene to Argus other than those as a sublicensee under the UTRC
License Agreement.

                  3.2 RGene agrees to pay the UTRC Running Royalties pursuant to
Article 4.1 B. and C. set forth in the UTRC License Agreement. Further, RGene
agrees to pay all UTRC Milestone Payments when due pursuant to Article 4.1 E. of
the UTRC License Agreement.

                  3.3 RGene agrees to make payment of all UTRC Running Royalties
and Milestone Payments directly to UTRC in accordance with Articles 4.2, 4.3,
4.4, 4.5 and 4.7 of the UTRC License Agreement.

                  3.4 Should RGene fail to make any payment or submit any report
as required under this Sublicense or under the UTRC License Agreement, Argus
shall have the option to terminate this Sublicense in accordance with the
provisions of Article 7.3 herein.

                  3.5 RGene agrees to maintain all reports, records, and allow
inspection as provided in Article 5 of the UTRC License Agreement and to submit
the written reports of Article 5.2 of the UTRC License Agreement directly to
UTRC.

IV.               PATENTS

                  4.1 Argus will provide RGene with any correspondence or
election notices received from UTRC pursuant to Section 6.1 of the UTRC License
Agreement immediately upon Argus' receipt thereof. RGene shall be entitled to
exercise all rights of Argus under Section 6.1 of the UTRC License Agreement.

                  4.2 RGene agrees to assume the rights and obligations of Argus
with respect to the patent related expenses set forth in Articles 6.2 and 6.3 of
the UTRC License Agreement.

                  4.3 RGene agrees to mark all products covered by the Licensed
Patent Rights with patent numbers in accordance with Article 6.5 of the UTRC
License Agreement.

                  4.4 RGene shall be entitled at its own expense to participate
in any lawsuit in which UTRC or Argus is a party that relates to the alleged
infringement of the rights to any issued patent included within the Licensed
Patent Rights, United States or foreign, by an unlicensed third party. Argus
shall not grant its consent, pursuant to 


                                      -3-
<PAGE>   25
Section 7.1 of the UTRC Agreement, to the grant by UTRC of any license under the
Licensed Patent Rights in the First Licensed Field without the prior written
consent of RGene, which shall not unreasonably be withheld.

V.                DEFENSE OF LEGAL ACTIONS; INSURANCE

                  5.1 In the event that UTRC, the University of Tennessee or
Argus, or any of their respective directors, officers, or employees, or any
individual named as an inventor of the Licensed Patent Rights (hereinafter
"Indemnified Party") is charged with infringement of a patent by a third party
or is made a party in any lawsuit (including but not limited to products
liability actions) as a result of the manufacture, use, or sale of any Licensed
Product under this Sublicense or as a result of any obligation or activity of
RGene under this Sublicense or the UTRC License Agreement, RGene shall:

                       (a) defend or settle, at RGene's expense, any claim of
infringement or lawsuit;

                       (b) assume all costs, expenses, damages, and other
obligations for payments incurred as a consequence of such charges of
infringement or lawsuit; and

                       (c) indemnify and hold such Indemnified Party harmless
for any and all damages, losses, liability, and costs resulting from such charge
of infringement or lawsuit.

                  5.2 At RGene's request, Argus and UTRC shall give RGene
assistance in the defense any such infringement charge or lawsuit.

                  5.3 Any Indemnified Party shall have the right to participate
in any defense, compromise or settlement to the extent that, in its judgment, it
may be prejudiced thereby.

                  5.4 RGene shall not settle any suit naming an Indemnified
Party without the prior written consent of each such Indemnified Party.

                  5.5 RGene shall not settle any claim or suit in any manner
that shall adversely affect any Licensed Patent Rights, require any payment by
any Indemnified Party, or reduce the royalty due to UTRC hereunder without the
prior written consent of UTRC. The foregoing shall apply even with regard to a
claim or suit in which UTRC is not a party.

                  5.6 RGene and Argus each agree to carry such liability
insurance as shall be mutually agreed for companies of their size and activities
operating in the 


                                      -4-
<PAGE>   26
pharmaceutical industry. At all times during the term of this Sublicense, UTRC
and Argus shall be listed as an additional named insured on such liability
insurance policy(ies) of RGene, and RGene shall be listed as an additional
insured on such liability insurance policies of Argus. RGene and Argus each
agree to provide written evidence of such insurance upon request by the other.

VI.               NEGATION OF WARRANTIES

                  6.1 NOTHING IN THIS AGREEMENT SHALL BE CONSTRUED AS:

                       (a) a warranty or representation by UTRC or Argus that
any patent application included within the Licensed Patent Rights will
ultimately issue as a patent;

                       (b) a warranty or representation as to the validity or
scope of any patent application or issued patent that may be included in the
Licensed Patent Rights;

                       (c) a warranty or representation that the use of the
Technology or the practice of the invention(s) covered by the Licensed Patent
Rights or the manufacture, use, or sale of the Licensed Products are or will be
free from infringement of patents of third parties;

                       (d) a requirement that UTRC or Argus shall be responsible
for the expenses of filing or prosecuting any patent application or maintaining
any patent in force;

                       (e) an obligation on the part of UTRC or Argus to bring
or prosecute actions or suits against third parties for infringement of the
Licensed Patent Rights or for unauthorized use of the Technology;

                       (f) an obligation on the part of UTRC or Argus to defend
any action or suit brought by any third party;

                       (g) a warranty or representation by UTRC or Argus as to
the safety, reliability, or efficacy of the Technology, the invention(s) covered
by the Licensed Patent Rights, or any product which incorporates or in its
production employs such Technology or invention(s);

                       (h) a warranty or representation by UTRC or Argus that
any Technology is secret or confidential; or

                                      -5-
<PAGE>   27
                       (i) a requirement that UTRC take any action to prevent
the disclosure of the Technology by the University of Tennessee, or its
employees, or any other third party.

                  6.2 UTRC and Argus make no representations, extend no
warranties of any kind, either express or implied, and UTRC assumes no
responsibilities whatever with respect to the manufacture, use, or sale, or
other disposition of the Licensed Products, or any other activities hereunder by
RGene, its customers, or any third parties.

VII.              TERM AND TERMINATION

                  7.1 This Agreement shall commence and become effective as
of the Effective Date.

                  7.2 Unless earlier determined in accordance with the
provisions set out herein, this Sublicense shall continue in full force and
effect until the expiration or termination of the UTRC License Agreement. Argus
agrees that it will not take any action to terminate the UTRC License Agreement
(except pursuant to Section 10.2 thereof) without the prior written consent of
RGene.

                  7.3 RGene shall be entitled to all rights of Argus under
Sections 10.3 and 10.5 under the UTRC License Agreement.

                  7.4 Should RGene fail to pay UTRC royalties or Milestone
Payments or any other payments due and payable hereunder, Argus shall have right
to terminate this Sublicense on thirty (30) days' written notice to RGene,
unless RGene shall within said thirty (30) day period pay UTRC all such amounts
due and payable, this Sublicense shall terminate at midnight on the 30th day,
all without prejudice to any rights or remedies otherwise available to Argus.

                  7.5 In the event that either party to this Sublicense defaults
in the due performance of its obligations or covenants hereunder or in the event
that any representation by either party proves to be false or incorrect in any
material respect, the other party may give notice of same the defaulting party
demanding that such default be cured within sixty (60) days. If the fault is not
cured within the sixty (60) day grace period, this Sublicense shall terminate at
midnight on the last day of such period, all without prejudice to any rights or
remedies otherwise available to the terminating party.

                  7.6 Upon any termination of this Sublicense by either party,
except pursuant to the provisions of Section 7.2 above;

                                      -6-
<PAGE>   28
                      (a) All rights granted to RGene hereunder shall terminate
automatically and shall revert to Argus; and

                      (b) RGene shall not thereafter utilize the Technology for
any purpose or manufacture, use, or sell Licensed Products under the Licensed
Patent Rights.

                  7.7 Within thirty (30) days after the termination of this
Sublicense for any reason, RGene shall duly account for and pay to UTRC all
royalties and other payments accrued as of the date of termination.

                  7.8 In the event of adjudication of bankruptcy, appointment of
a receiver by a court of competent jurisdiction, assignment for the benefit of
creditors, or where levy or execution directly involves all the substantial
assets of RGene or if RGene goes out of business, this Sublicense shall
automatically terminate effective the date of such action; provided, however,
that such termination shall not impair or prejudice any right or remedy that
Argus may otherwise have.

                  7.9 Termination of this Sublicense for any cause shall not be
construed to release RGene from any royalty or confidentiality obligation or any
obligation under Article V (all of which shall survive the termination of this
Sublicense) or from any other obligation matured prior to the effective date of
such termination.

VIII.             CONFIDENTIALITY

                  8.1 RGene agrees that reasonable and prudent practices shall
be followed to maintain the confidential nature of the Technology that is not
public knowledge, including where necessary, obtaining written confidentiality
agreements from employees not already bound by such agreements and all employees
of same who have access to such Technology. Argus and RGene each agree that all
information relating to this Sublicense and the Technology and improvements
sublicensed hereunder contained in documents made "Confidential" which are
forwarded to one by the other (or between UTRC and either party) shall be
received in strict confidence, shall be used only for the purpose of this
Sublicense, and shall not be disclosed by the receiving party (except as
required by law), its agents or employees without the prior written consent of
the forwarding party, unless such information (i) was in the public domain at
the time of disclosure, (ii) later becomes part of the public domain through no
act or omission of the receiving party, its employees, agents, successors or
assigns, (iii) was lawfully disclosed to the receiving party by a third party
having a right to disclose it, (iv) was already known to the receiving party at
the time of disclosure, (v) was independently conceived, discovered or reduced
to practice, (vi) is required to be submitted to a government agency pursuant to
any obligation imposed or right granted hereunder, (vii) is required by law or
court order 


                                      -7-
<PAGE>   29
to be disclosed, or (viii) is disclosed by the University of Tennessee, UTRC, or
McMaster in the exercise of rights under Article 15.1 of the UTRC License
Agreement. The foregoing obligation of confidentiality shall survive the
termination of this Sublicense for any reason for a period of ten (10) years
thereafter. In addition, RGene shall be entitled to the benefit of all rights of
Argus pursuant to Section 11.1 of the UTRC License Agreement.

IX.               MISCELLANEOUS

                  9.1 It is understood that this Sublicense contains the entire
agreement between the parties relating to the subject matter of this Sublicense.
Neither party shall be bound by any agreement, covenants or warranties unless it
shall be reduced to writing and signed by an officer of such party. The failure
of either of the parties at any time or times to require the performance by the
other of any provisions hereof shall in no matter affect the right of the first
mentioned party thereafter to enforce the same. The waiver by either of the
parties of any breach of any provision hereof shall never be construed to be a
waiver of any succeeding breach of such provision or a waiver of the provision
itself.

                  9.2 This Sublicensee shall be binding upon and shall enure to
the benefit of Argus and its assigns and successors in interest and shall be
binding upon and shall enure to the benefit of RGene and its assigns and
successors in interest provided that such successor shall agree in writing to be
bound in all respect thereby. This Sublicense shall not be assignable or
assigned by RGene without the prior written approval of UTRC, as required by the
UTRC License Agreement, which approval shall not be unreasonably withheld.

                  9.3 All payments, notices and other communications to the
parties shall be deemed to be given and received two (2) days after the date of
mailing when sent by certified or registered United States mail, return receipt
requested, and addressed as set out below. Otherwise, a payment, notice, or
other communication shall be deemed to be given and received on the date of
actual receipt by the addressee.

                      (a) If to RGene:

                          RGENE THERAPEUTICS, INC.
                          2170 Buckthorne Place, Suite 170
                          The Woodlands, Texas 77381

                                      -8-
<PAGE>   30
                      (b) If to Argus:

                          ARGUS PHARMACEUTICALS, INC.
                          3400 Research Forest Drive
                          The Woodlands, Texas 77381

                      (c) If to UTRC:

                           UNIVERSITY OF TENNESSEE
                           RESEARCH CORPORATION
                           415 Communications Building
                           Knoxville, Tennessee 37996-0344

                  9.4 Either party may change its address by written notice duly
given to the other party. A post office receipt showing the date of deposit
shall be prima facie evidence of mailing when sent by certified or registered
United States mail.

                  9.5 RGene will comply with the terms of Section 15.1 of the
UTRC License Agreement.

                  9.6 Each party shall be deemed to be an independent contractor
and this Sublicense shall not constitute a partnership or a joint venture, and
neither party shall be bound by the other to any contract, arrangement or
understanding except as specifically stated herein.

                  9.7 Prior written approval must be obtained for the use of
UTRC's, McMaster's, or the University of Tennessee's name, logo or associated
symbols in any form of advertising.

                  9.8 RGene shall be solely responsible for the payment and
discharge of any taxes or duties relating to any transactions of RGene, its
employees, contractors, or agents in connection with the manufacture, use, or
sale in any country of Licensed Products.

                  9.9 RGene shall, at its own expense, be responsible for
applying for and obtaining any approvals, authorizations, or validations
required under the laws of the United States or a foreign country that may be
necessary for the manufacture, use, or sale of License Products or relative to
the performance of any obligation under this Sublicense.

                  9.10 The failure of either party to enforce at any time any of
the provisions of this Sublicense, or any rights in respect thereto, or to
exercise any election herein provided, shall in no way be considered to be a
waiver of such provisions, rights or

                                      -9-
<PAGE>   31
elections, or in any way to affect the validity of this Sublicense. Exercise by
either party of any of these rights herein or any of its elections under the
terms or covenants herein shall not preclude either party from exercising the
same or any other rights in this Sublicense irrespective of any previous action
or proceeding taken by either party hereunder.

                  9.11 If any provision of this Sublicense is judicially or in
an arbitration proceeding determined to be void or unenforceable, such provision
shall be deemed to be severable from the other provisions of this Sublicense
which shall remain in full force and effect. Either party may request that a
provision otherwise void or unenforceable be reformed so as to be valid and
enforceable to the maximum extent permitted by law.

                  9.12 No liability hereunder shall result to a party by reason
of delay in performance caused by force majeure, that is, circumstances beyond
reasonable control of the party, including, without limitation, acts of God,
fire, flood, war, civil unrest, labor unrest, or shortage or inability to obtain
material or equipment.

                  9.13 The signature on the part of UTRC appears below as the
licensor of the Licensed Patent Rights and the Technology for the purpose of
indicating its approval of the provisions of Sublicense and indicating its
agreement not to take any action in derogation of the rights herein granted to
RGene. It is understood and agreed by RGene that Argus shall have no
responsibility or liability for any act or omission to act on the part of UTRC
or McMaster and UTRC and McMaster shall have no responsibility or liability for
any act or omission to act on part of Argus.

                  9.14 This Agreement shall have no force and effect unless and
until duly executed by both parties.

                  9.15 This Sublicense is deemed to have been made in the State
of Texas and shall be interpreted and construed and any legal relations created
hereunder shall be determined in accordance with the laws of the State of Texas.

                  IN WITNESS WHEREOF, signifying their acceptance of and
agreement to be bound by terms and conditions of this Agreement, the signature
of the parties are affixed hereto.

RGENE THERAPEUTICS, INC.                       ARGUS PHARMACEUTICALS, INC.

By:  /s/ MARTIN P. SUTTER                      By:  /s/ DAVID M. LEECH
   --------------------------                     -----------------------------



                                      -10-
<PAGE>   32
Name:   Martin P. Sutter                Name:     David M. Leech
     ----------------------------
Title:  Chairman                        Title:    President & CEO
      ---------------------------
Date:   April 6, 1994                   Date:     April 6, 1994
     ----------------------------             -------------------------------

APPROVED BY THE UNIVERSITY OF 
TENNESSEE RESEARCH 
CORPORATION

By:  /s/ ANN J. ROBERSON
    ----------------------------------
Name:    Ann J. Roberson
      --------------------------------
Title:   President
      --------------------------------
Date:    April 7, 1994
      --------------------------------

                                      -11-
<PAGE>   33
                                                                     EXHIBIT 3.1
<TABLE>
<CAPTION>
AR-GENE BUDGET

      GROUP               BUDGET ITEM    1ST 6 MONTH    2ND 6 MONTH    3RD 6 MONTH    4TH 6 MONTH
      -----               -----------    -----------    -----------    -----------    -----------    -----------
<S>                       <C>            <C>            <C>            <C>            <C>            <C> 

     ARGUS                [*]

     L. HUANG             [*]

     G. LOPEZ             [*]

     M. HUNG              [*]

     PASS THRU            [*]
</TABLE>

- --------------------

[*] Confidential Treatment Requested.

<PAGE>   34
                                                                     EXHIBIT 3.2

                            RGENE THERAPEUTICS, INC.

                              STOCKHOLDER AGREEMENT

                  This Stockholder Agreement (this "Agreement") dated April 6,
1994 is entered into by and between RGene Therapeutics, Inc., a Delaware
corporation (the "Company"), and Argus Pharmaceuticals, Inc., a Delaware
corporation ("Stockholder").

                                   WITNESSETH:

                  WHEREAS, the Company desires to issue certain shares of common
stock, $.001 par value, of the Company (the "Common Stock") to the Stockholder;
and

                  WHEREAS, the Stockholder desires to acquire certain shares of
Common Stock from the Company; and

                  WHEREAS, the Stockholder and the Company desire that the
Stockholder grant to the Company, and under certain circumstances to holders of
the Company's Preferred Stock or other securities issued by the Company to
investors (the "Investors"), options to repurchase certain shares of Common
Stock purchased by the Stockholder on the terms and conditions set forth;

                  NOW, THEREFORE, for and in consideration of the mutual
promises, covenants and obligations contained herein, the parties agree as
follows:

                  1.   ISSUANCE OF SHARES

                       1.1 PURCHASE AND SALE OF SHARES

                  Subject to the terms and conditions of this Agreement and in
consideration of the execution of (i) that certain Assignment Agreement between
the Company and the Stockholder dated the date hereof relating to certain patent
applications and technology currently licensed to Stockholder by The University
of Texas M.D. Anderson Cancer Center and The University of Texas System Board of
Regents pursuant to an Exclusive License Agreement dated July 1, 1988, and (ii)
that certain Sublicense Agreement between the Company and the Stockholder dated
the date hereof relating to certain patent applications and technology rights
currently licensed to Stockholder by the University of Tennessee Research
Corporation pursuant to an Agreement dated November 1, 1993, the Company agrees
to issue to the Stockholder 642,307 shares of Common Stock (the "Shares") at the
Closing (as defined below).
<PAGE>   35
                     1.2 CLOSING

                  The closing for the issuance of the Shares to the Stockholder
shall occur on or before April 6, 1994, or at such other date and time as the
parties may agree (the "Closing"). At the Closing, or within a reasonable time
thereafter, the Company shall deliver to Stockholder a certificate or
certificates representing the number of Shares as set forth in Section 1.1
hereof, in the name of the Stockholder.

                  2. REPRESENTATIONS AND WARRANTIES

                  To induce the Company to deliver the Shares to the
Stockholder, the Stockholder represents and warrants to the Company:

                     (a) The Stockholder is acquiring the Shares for its own
account as principal, for investment purposes only, and not with a view to, or
for, resale or distribution, and no other person or entity has a direct or
indirect beneficial interest in the Shares;

                     (b) The Stockholder has not offered any of the Shares for
resale and has no present intention of dividing its interest with others or of
reserving or otherwise disposing of any of the Shares;

                     (c) Any information the Stockholder has furnished to the
Company with respect to the Stockholder's status as a sophisticated or
accredited investor, its business experience or financial position is correct;

                     (d) The financial capacity of the Stockholder is such that
the investment in the Shares is not material to its total financial capacity;
the Stockholder has the financial ability to bear the economic risk of its
investment, has adequate means for providing for its current needs and personal
contingencies and has no need for liquidity with respect to its investment in
the Shares;

                     (e) The Stockholder considers itself to be a sophisticated
investor and has such knowledge and experience in financial and business matters
as to be capable of evaluating the merits and risks of the prospective
investment in the Shares;

                     (f) The Stockholder has been furnished with all information
concerning the Shares and the Company that it desires;

                     (g) The Stockholder has been given the opportunity to ask
questions of, and receive answers from, the Company with respect to the Shares,
concerning the terms and conditions of the offering and other matters pertaining
to this investment, and has been given the opportunity to obtain such additional
information necessary to verify the accuracy of the information provided to him
by the Company in order for him to evaluate 

                                      -2-
<PAGE>   36
the merits and risks of investment in the Shares to the extent that the Company
possessed such information or could acquire it without unreasonable effort or
expense; and

                     (h) The Stockholder is not relying on the Company with
respect to any economic considerations of the Stockholder related to this
investment. In regard to the economic considerations related to this investment,
the Stockholder has relied on the advice of, or has consulted with, only its own
advisors.

                  The Stockholder further represents, warrants and agrees that
it will not sell or otherwise transfer the Shares without registration under the
Securities Act of 1933, as amended (the "Act"), or an exemption therefrom, and
fully understands and agrees that it must bear the economic risk of its purchase
for an indefinite period of time because, among other reasons, the Shares have
not been registered under the Act or under the securities laws of any state and,
therefore, cannot be resold, pledged, assigned or otherwise disposed of unless
they are subsequently registered under the Act and under the applicable
securities laws of such states or an exemption from such registration is
available. It also understands that the Company is under no obligation to
register the Shares on its behalf or to assist him in complying with any
exemption from registration under the Act. It further understands that any
certificate evidencing the Shares will bear a legend restricting the transfer
thereof consistent with the foregoing and that a notation may be made in the
records of the Company restricting the transfer of any Shares in a manner
consistent with the foregoing.

                  3.  STOCKHOLDER AWARENESS

                  The Stockholder acknowledges that it is aware that:

                     (a) No federal or state agency has passed upon the Shares
or made any finding or determination as to the fairness of this investment;

                     (b) There are substantial risks of loss of investment
incident to an investment in the Shares and such an investment is highly
speculative;

                     (c) The Company is only recently organized, has not
conducted any substantial business to date and does not have any substantial
working capital or financial resources. The business in which the Company
proposes to engage is highly competitive and success in the Company's business
may depend on, among other things, the Company's ability to obtain financing, to
complete product development, to attract qualified employees and to obtain
patent protection and governmental approvals, market acceptance of products and
numerous other factors over which the Company does not have control.

                                      -3-
<PAGE>   37
                  4. RESTRICTIONS ON TRANSFER; RIGHT OF FIRST REFUSAL

                     4.1 COMPANY'S PURCHASE OPTION

                  Stockholder shall not sell, transfer, pledge, hypothecate or
otherwise dispose of any Shares which are purchased hereunder without first
complying with the terms of this Section 4.

                     4.2 RIGHT OF FIRST REFUSAL

                  Before any of the Shares registered in the name of Stockholder
may be sold or transferred (including transfer by operation of law), except as
permitted in Section 5, such Shares shall first be offered to the Company and to
the Investors, in accordance with the terms set out herein.

                      (i) Stockholder shall deliver a notice ("Notice") to the
                  Company and to the Investors stating (A) its bona fide
                  intention to sell or transfer such Shares, (B) the number of
                  such Shares to be sold or transferred, (C) the price for which
                  it proposes to sell or transfer such Shares, and (D) the name
                  of the proposed purchaser or transferee.

                      (ii) Within thirty (30) days after receipt of the Notice,
                  the Company and/or the Investors may elect to purchase all but
                  not less than all of the Shares to which the Notice refers, at
                  the price per share specified in the Notice. The closing for
                  such purchase by the Company and/or the Investors shall occur,
                  unless otherwise agreed by the Company, the Investors electing
                  to purchase Shares, and the Stockholder, no later than 30 days
                  after the election by the Company and/or the Investors to
                  purchase same. In the event that the number of Shares which
                  the Company and the Investors desire to purchase exceeds the
                  number of Shares proposed for sale by Stockholder in the
                  Notice, then in such instance the Company shall have full
                  preference to acquire such Shares to the exclusion of the
                  Investors, and, to the extent that there are Shares still
                  available for purchase by the Investors, the Investors
                  desiring to purchase Shares shall be entitled to purchase the
                  remaining amount thereof on a pro rata basis based upon the
                  number of shares of Common Stock and Preferred Stock, or
                  securities convertible into shares of Common Stock and
                  Preferred Stock, then held by each of them so electing to
                  purchase bears to the total number of shares of Common Stock
                  and Preferred Stock, or securities convertible into shares of
                  Common Stock and Preferred Stock, held by all Investors
                  desiring to acquire Shares, on a fully diluted as if converted
                  to Common Stock basis.

                      (iii) If the Shares to which the Notice refers are not
                  purchased by the Company and the Investors, as provided in
                  Section 4.2(ii) hereof, Stockholder may sell such Shares which
                  the Company and the Investors elected not to purchase to



                                      -4-
<PAGE>   38
                  any person or persons named in the Notice at the price
                  specified in the Notice or at a higher price, provided that
                  such sale or transfer is consummated within 120 days of the
                  date of said Notice to the Company and the Investors, and
                  provided, further, that any such sale is in accordance with
                  all the terms and conditions hereof.

                      (iv) Upon the closing of a firm commitment public offering
                  pursuant to an effective registration statement filed by the
                  Company under the Securities Act of 1933, as amended (the
                  "Act"), covering the offering and sale of shares of Common
                  Stock for the account of the Company in which the aggregate
                  gross proceeds received by the Company equal or exceed
                  $7,500,000 and in which the public offering price per share
                  equals or exceeds $5.00 per share, the thirty (30) day period
                  specified in Section 4.2(ii) above shall be reduced to a ten
                  (10) day period; and the requirement to identify the name of
                  the proposed purchaser and the proposed price shall be
                  inapplicable if the Stockholder proposed to sell the Shares in
                  an over-the-counter sale or on a national or regional exchange
                  transaction. In such instance, any such sale to the Company
                  and/or the Investors shall be at the average closing price of
                  the Company's Common Stock on the date of notice of election
                  to purchase such shares by the Company and/or the Investors.
                  The average closing price is defined as the last closing price
                  regular way on the exchange where the Common Stock is listed
                  for trading or the average of the bid and ask prices if
                  applicable.

                      4.3 STANDOFF AGREEMENT

                  Stockholder agrees, in connection with each of the Company's
public offerings of its equity securities, and upon request of the Company or
the underwriters managing such offering, not to sell, make any short sale of,
loan, grant any option for the purchase of or otherwise dispose of any of the
Shares (other than those included in the registration, if any) without the prior
written consent of the Company or such underwriters, as the case may be, for
such period of time from the effective date of such registration as may be
requested by the Company or such underwriters; provided, that the officers and
directors of the Company who own stock of the Company also agree to such
restrictions.

                      4.4 OTHER RESTRICTIONS ON TRANSFER

                  The Company shall not be required (i) to transfer on its books
any of the Shares which shall have been sold or transferred in violation of any
of the provisions set forth in this Agreement, or (ii) to treat as owner of such
Shares or to accord the right to vote as such owner or to pay dividends to any
transferee to whom such Shares shall have been so transferred.

                                      -5-
<PAGE>   39
                  5. EXEMPT TRANSACTIONS

                  The prohibition in Section 4 against the sale of the Shares
shall not apply to the exchange of Shares pursuant to a plan or merger,
consolidation, recapitalization, reorganization, or sale of the Stockholder in
which the Stockholder is the surviving entity, but any stock or securities
received in exchange therefor shall also become subject to this Agreement.

                  6. ASSIGNMENT

                  The Company may assign this Agreement or any of its rights and
obligations hereunder. The Stockholder may not assign this Agreement or any of
its rights and obligations hereunder. All covenants and agreements of, and
benefits for, the Investors contained in this Agreement shall inure to the
benefit of their respective successors and assigns and be binding on the Company
and its successors and on the Stockholder and its successors and assigns. All
such covenants and agreements are fully assignable by the Investors, provided,
however, that any assignment of any of its rights under this Agreement by any
Investor (other than to partners of such Investor or successors of such Investor
or such partners by operation of law) shall be made only in connection with the
sale or other transfer of all or any portion of the Preferred Stock, Common
Stock, convertible notes, warrants, options or other securities of the Company
which are exchangeable or convertible into shares of Common Stock or Preferred
Stock of the Company held by such Investor and such assignee or transferee shall
execute this Agreement.

                  7. ADJUSTMENTS

                  If, from time to time during the term of this Agreement (i)
there is any stock dividend or liquidating dividend of cash or property, stock
split or other change in the character or amount of any of the outstanding
securities of the Company, or (ii) there is any transaction involving the
consolidation, merger or sale of all, or substantially all, of the assets of the
Company, then, in such event, (x) any and all new, substituted or additional
securities or other property to which the Stockholder is entitled by reason of
its ownership of the Shares shall be immediately subject to right of first
refusal provided to the Company and the Investors as described in Section 4
hereof and (y) all Shares purchased by Stockholder hereunder shall be treated on
the same basis as all other outstanding shares of Common Stock of the Company so
that Stockholder's Shares shall not be diluted by any such event any differently
than any other holder of Common Stock of the Company.

                  8. LEGENDS

                  All certificates representing any of the Shares subject to the
provisions of this Agreement shall have endorsed thereon a legend substantially
as follows:

                                      -6-
<PAGE>   40
                       "ANY DISPOSITION, GRANT OR OTHER TRANSFER OF
                       ANY INTEREST IN THE SECURITIES REPRESENTED
                       BY THIS CERTIFICATE IS SUBJECT TO CERTAIN
                       RESTRICTIONS, AND THE SECURITIES REPRESENTED
                       BY THIS CERTIFICATE ARE SUBJECT TO A RIGHT
                       OF FIRST REFUSAL, CONTAINED IN A CERTAIN
                       AGREEMENT BY THE RECORDHOLDER HEREOF AND THE
                       CORPORATION, A COPY OF WHICH WILL BE MAILED
                       TO ANY HOLDER OF THIS CERTIFICATE WITHOUT
                       CHARGE AFTER RECEIPT BY THE CORPORATION OF A
                       WRITTEN REQUEST THEREFOR."

                  Upon presentation to the Company or any authorized transfer
agent, the certificates representing the Shares or any appropriate portion
thereof shall be exchanged for certificates not bearing such legend if the
certificates are presented after the termination of this Agreement.

                  9.   RIGHTS AS A STOCKHOLDER; VOTING AGREEMENT

                       (a) Subject to the provisions of Section 4 above, the
Stockholder shall, during the term of this Agreement, exercise all rights and
privileges of a stockholder of the Company with respect to the Shares, including
the right to vote such Shares at any stockholder meeting. Notwithstanding
anything herein to the contrary, Stockholder hereby agrees that it will, for a
ninety-day period following the issuance of the Shares or until the closing of
the first round financing by the Company in an amount at least equal to
$2,000,000, whichever comes first, vote such Shares, at any stockholder meeting,
in person, by proxy, by written consent, or otherwise, for the directors
nominated for election to the Board of Directors of the Company by The Woodlands
Venture Fund and no others, and, in any other matter coming before the
stockholders of the Company, in accordance with the directive of The Woodlands
Venture Fund.

                  In order to secure the obligation to vote in accordance with
the provisions hereof, the Stockholder hereby appoints Martin P. Sutter as its
true and lawful proxy and attorney, with full power of substitution, to vote all
of its Shares for the matters specified hereinabove. The irrevocable proxy
granted by the Stockholder may be exercised at any time Stockholder fails to
comply with the terms of this Section 9. The proxy and power granted by the
Stockholder pursuant to this Section are coupled with an interest and are given
to secure the duties of the Stockholder pursuant hereto. Such proxy will be
irrevocable and will survive the bankruptcy, liquidation, dissolution, merger,
consolidation or other reorganization of Stockholder, provided that it shall
terminate upon the expiration of such ninety (90) day period following the
issuance of the Shares or the closing of the above-referenced financing,
whichever comes first.

                                      -7-
<PAGE>   41
                  Stockholder hereby consents to the placement of an appropriate
legend evidencing the voting restrictions provided for in this Agreement, on the
certificates representing the Shares and any certificates issued in replacement
or exchange therefor, and Stockholder will take all actions reasonably requested
by the Company to effect such placement.

                       (b) The Company agrees that it will provide Stockholder
with "piggyback" registration rights, that is, rights to register the Shares
purchased by Stockholder under this Agreement in a public offering of equity
securities conducted by the Company by or on behalf of stockholders of the
Company on terms which are identical to the piggyback registration rights
provided to the holders of shares of Series A Preferred Stock of the Company, on
a pari passu basis.

                  10. TERMINATION

                  Except as may be otherwise provided herein, this Agreement
shall terminate on the 91st calendar day immediately succeeding the third
anniversary of the public offering referenced in Section 4.2.

                   11. MISCELLANEOUS

                       11.1 NOTICE

                  For purposes of this Agreement, notices and all other
communications provided for herein shall be in writing and shall be deemed to
have been duly given when personally delivered or when mailed by United States
registered or certified mail, return receipt requested, postage prepaid,
addressed as follows:

                  If to the Company:

                             RGene Therapeutics, Inc.
                             The Woodlands Venture Fund
                             2170 Buckthorne Place, Suite 170
                             The Woodlands, Texas 77380
                             Attention:  Martin P. Sutter

                  If to the Stockholder, at the address identified on the
signature page hereof, and if to an Investor, at the address identified on the
records of the Company hereto, or to such other address as either party or an
Investor may furnish to the other in writing in accordance herewith, except that
notices of change of address shall be effective only upon receipt.

                       11.2 APPLICABLE LAW

                  The substantive laws of the State of Texas, excluding any law,
rule or principle which might refer to the substantive law of another
jurisdiction, will govern the 


                                      -8-
<PAGE>   42
interpretation, validity and effect of this Agreement without regard to the
place of execution or the place for performance thereof. This Agreement is to be
at least partially negotiated, executed and performed in Harris County, Texas,
and, as such, the Company and the Stockholder agree that personal jurisdiction
and venue shall be proper with the state or federal courts situated in Harris
County, Texas, to hear such disputes arising under this Agreement.

                       11.3 NO WAIVER

                  No failure by either party hereto at any time to give notice
of any breach by the other party of, or to require compliance with, any
condition or provision of this Agreement shall be deemed a waiver of similar or
dissimilar provisions or conditions at the same or at any prior or subsequent
time.

                       11.4 SEVERABILITY

                  If a court of competent jurisdiction determined that any
provision of this Agreement, including any appendices attached hereto, is
invalid or unenforceable, then the invalidity or unenforceability of that
provision shall not affect the validity or enforceability of any other provision
of this Agreement, and all other provisions shall remain in full force and
effect. Further, such provision shall be reformed and construed to the extent
permitted by law so that it may be valid, legal and enforceable to the maximum
extent possible.

                       11.5 COUNTERPARTS

                  This Agreement may be executed in one or more counterparts,
each of which shall be deemed to be an original, but all of which together will
constitute one and the same Agreement.

                       11.6 HEADINGS

                  The section headings have been inserted for purposes of
convenience and shall not be used for interpretive purposes.

                       11.7 SUCCESSORS; THIRD PARTY BENEFICIARY

                  This Agreement shall inure to the benefit of the successors
and assigns of the Company and the Investors and be binding upon the Stockholder
and its successors and assigns. The Stockholder agrees that any and all
Investors in the Company shall be treated as third party beneficiaries of this
Agreement without the necessity of execution of this Agreement, and shall be
entitled to all of the rights rendered to them herein.

                                      -9-
<PAGE>   43
                       11.8 ENTIRE AGREEMENT

                  This Agreement constitutes the entire agreement of the parties
with regard to the subject matter hereof, and contains all the covenants,
promises, representations, warranties and agreements between the parties with
respect to the subject matter hereof. Each party to this Agreement acknowledges
that no representation, inducement, promise or agreement, oral or written, with
regard to the subject matter hereof, has been made by either party, or by anyone
acting on behalf of either party, which is not embodied herein, and that no
agreement, statement or promise relating to the subject matter hereof which is
not contained in this Agreement or in such other agreements shall be valid and
binding.

                       11.9 AMENDMENT

                  No amendment or modification to this Agreement will be
effective unless it is in writing and signed by the Company, the Stockholder
and, if such amendment alters or amends any of the rights of the Investors, by
Investors holding a majority of the outstanding shares of capital stock of the
Company held by such Investors, if any.

                       11.10 INDEMNITY

                  The Stockholder agrees to indemnify and hold harmless the
Company and any person, if any, who controls the Company or such successor
within the meaning of Section 15 of the Act against any and all loss, liability,
claim, damage and expense whatsoever (including, but not limited to, any and all
expenses whatsoever reasonably incurred in investigating, preparing or defending
against any litigation commenced or threatened or any claim whatsoever) arising
out of or based upon any false representation or warranty or breach or failure
by the Stockholder to comply with any covenant or agreement made by the
Stockholder herein or in any other document furnished by the Stockholder in
connection with this transaction.

                       11.11 INJUNCTIVE RELIEF

                  In view of the inadequacy of money damages, and in view of the
fact that the stock of the Company cannot be readily purchased or sold in the
general market, if the Stockholder or any other person shall fail to comply with
any provision of this Agreement, the Company shall be entitled, to the extent
permissible by law, to injunctive relief in the case of the violation, or
attempted or threatened violation, by Stockholder or other person of any such
provision, or to a decree compelling specific performance by the Stockholder or
other person, of any such provision, or to any other remedies legally available.

                                      -10-
<PAGE>   44
                       11.12 VOID TRANSFERS

                  If any Stock shall be sold or transferred otherwise than in
accordance with the terms and conditions of this Agreement, such sale shall be
void. Any such attempted sale or other transfer shall create a right in the
Company to purchase the Stock which is the subject of such purported transfer at
the applicable purchase price specified herein. Such right shall constitute an
"adverse claim" within the meaning of such term as used within the meaning of
the Uniform Commercial Code of any State. In addition to, and without prejudice
to, any and all other rights or remedies which may be available to the Company,
the Stockholder agrees that the Company may, but shall have no obligation to,
hold and refuse to transfer any Stock, or any certificate therefor, tendered to
it for transfer if the transfer violates the provisions of the Agreement.

                       11.13 TAX REPRESENTATIONS

                  The Stockholder acknowledges that the Company has made no
warranties or other representations to Stockholder with respect to the income
tax consequences of the transactions contemplated by this Agreement and
Stockholder is in no manner relying on the Company or its representatives for an
account of such tax consequences.

                       11.14 FURTHER ASSURANCES

                  The parties agree to execute such further instruments and to
take such further action as may reasonably be necessary to carry out the intent
of this Agreement.

                  IN WITNESS WHEREOF, the parties have caused this Agreement to
be executed and delivered as of the day and year first above written.

                                       Company

                                       RGENE THERAPEUTICS, INC.

                                       By:     /s/ MARTIN P. SUTTER
                                           -----------------------------
                                       Name:   Martin P. Sutter
                                              --------------------------
                                       Title:  Chairman
                                              --------------------------
                                       Stockholder

                                      -11-
<PAGE>   45
                                       ARGUS PHARMACEUTICALS, INC.

                                       By:     /s/ D.M. LEECH
                                           -----------------------------
                                       Name:   D.M. Leech
                                              --------------------------
                                       Title:  President/CEO
                                              --------------------------


                                      -12-
