<SUBMISSION>
<ACCESSION-NUMBER>0000950123-01-002445
<TYPE>SC TO-T/A
<PUBLIC-DOCUMENT-COUNT>2
<FILING-DATE>20010320
<GROUP-MEMBERS>INDIGO ACQUISITION CORP
<GROUP-MEMBERS>INVERESK RESEARCH (CANADA) INC
<GROUP-MEMBERS>INVERESK RESEARCH GROUP LTD
<SUBJECT-COMPANY>
<COMPANY-DATA>
<CONFORMED-NAME>CLINTRIALS RESEARCH INC
<CIK>0000870978
<ASSIGNED-SIC>8734
<IRS-NUMBER>621406017
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>SC TO-T/A
<ACT>34
<FILE-NUMBER>005-48381
<FILM-NUMBER>1572661
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>11000 WESTON PARKWAY
<CITY>CARY
<STATE>NC
<ZIP>27513
<PHONE>9194622556
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>11000 WESTON PARKWAY
<CITY>CARY
<STATE>NC
<ZIP>27513
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>CLINTRIALS INC
<DATE-CHANGED>19930930
</FORMER-COMPANY>
</SUBJECT-COMPANY>
<FILED-BY>
<COMPANY-DATA>
<CONFORMED-NAME>INVERESK RESEARCH GROUP LTD
<CIK>0001135362
<ASSIGNED-SIC>
<IRS-NUMBER>000000000
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>SC TO-T/A
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>ELPHINSTONE RESEARCH CENTRE
<STREET2>TRANENT, EAST LOTHIAN EH33 2NE
<CITY>UNITED KINGDOM
<PHONE>4401875614545
</BUSINESS-ADDRESS>
</FILED-BY>
<DOCUMENT>
<TYPE>SC TO-T/A
<SEQUENCE>1
<FILENAME>y46719a2scto-ta.txt
<DESCRIPTION>AMENDMENT NO. 2 TO SCHEDULE TO
<TEXT>

<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                            -------------------------
                               AMENDMENT NO. 2 TO
                                   SCHEDULE TO
                                 (RULE 14d-100)

               TENDER OFFER STATEMENT PURSUANT TO SECTION 14(d)(1)
                     OF THE SECURITIES EXCHANGE ACT OF 1934

                            CLINTRIALS RESEARCH INC.
                       (Name of Subject Company (Issuer))

                            INDIGO ACQUISITION CORP.
                          a wholly owned subsidiary of
                         INVERESK RESEARCH (CANADA) INC.
                          a wholly owned subsidiary of
                         INVERESK RESEARCH GROUP LIMITED
                       (Name of Filing Persons (Offerors))

                          COMMON STOCK, $0.01 PAR VALUE
                         (Title of Class of Securities)

                                    188767107
                      (CUSIP Number of class of securities)

                                STEWART G. LESLIE
                         INVERESK RESEARCH GROUP LIMITED
                           ELPHINSTONE RESEARCH CENTRE
                         TRANENT, EAST LOTHIAN EH33 2NE
                            SCOTLAND, UNITED KINGDOM
                               +44 (1875) 614-545

        (Name, Address and Telephone No. of Person Authorized to Receive
             Notices and Communications on Behalf of Filing Persons)

                                 with a copy to:
                               JOHN A. HEALY, ESQ.
                       CLIFFORD CHANCE ROGERS & WELLS LLP
                                200 PARK AVENUE,
                            NEW YORK, NEW YORK 10166
                                 (212) 878-8000

                            -------------------------
                            CALCULATION OF FILING FEE

<TABLE>
<CAPTION>
--------------------------------------------------------------------------------
             TRANSACTION VALUATION                     AMOUNT OF FILING FEE
             <S>                                       <C>
                  $123,490,056                               $24,699*
--------------------------------------------------------------------------------
</TABLE>
   * Previously paid.


  [ ] Check the box if the filing relates solely to preliminary communications
      made before commencement of a tender offer.

      Check the appropriate boxes below to designate any transactions to which
      the statement relates:

      [X]  third-party tender offer subject to Rule 14d-1.
      [ ]  issuer tender offer subject to Rule 13e-4.
      [ ]  going-private transaction subject to Rule 13e-3.
      [ ]  amendment to Schedule 13D under Rule 13d-2.


  Check the following box if the filing is a final amendment reporting the
      results of the tender offer: [ ]




<PAGE>   2



                         AMENDMENT NO. 2 TO SCHEDULE TO

        This Amendment No. 2 amends and supplements the Tender Offer Statement
on Schedule TO, originally filed with the Securities and Exchange Commission
(the "Commission") on March 5, 2001, as amended by Amendment No. 1 filed with
the Commission on March 19, 2001 (the "Schedule TO"), relating to the offer by
Indigo Acquisition Corp., a Delaware corporation ("Purchaser"), which is a
wholly owned subsidiary of Inveresk Research (Canada) Inc., a corporation
organized under the laws of Canada ("Inveresk Canada"), which, in turn, is a
wholly owned subsidiary of Inveresk Research Group Limited, a company organized
under the laws of Scotland ("Parent"), to purchase all of the outstanding shares
of common stock, par value $0.01 per share (the "Shares"), of ClinTrials
Research Inc., a Delaware corporation (the "Company") at a price of $6.00 per
Share, net to the seller in cash, upon the terms and subject to the conditions
set forth in the Offer to Purchase, dated March 5, 2001 (the "Offer to
Purchase"), a copy of which was attached as Exhibit (a)(1) to the Schedule TO,
and in the related Letter of Transmittal, a copy of which was attached to the
Schedule TO as Exhibit (a)(2).

SCHEDULE TO

        The Schedule TO is hereby supplemented and/or amended as provided below.

ITEM 11.  ADDITIONAL INFORMATION.

        Item 11 of the Schedule TO is amended by adding the following:

        The applicable waiting period under the U.S. Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended, expired on Monday, March 19, 2001.

        The offer remains conditioned upon, among other things, the Company's
shareholders tendering and not withdrawing prior to the expiration of the offer
at least a majority of the total number of all outstanding Shares plus all
Shares issuable upon exercise of options and other similar rights to purchase
Shares.

        For additional information regarding the expiration of the waiting
period, see the text of the press release filed as an exhibit hereto.

ITEM 12.  EXHIBITS.

        Item 12 of the Schedule TO is amended by adding the following:

        (a)(10) Press release issued by Parent, dated March 20, 2001, announcing
               the expiration of the waiting period under the HSR Act.









                                     - 2 -

<PAGE>   3





                                    SIGNATURE

        After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Date: March 20, 2001                  INDIGO Acquisition Corp.


                                      /s/ Walter Nimmo
                                      -----------------------------------------
                                      Name:  Walter Nimmo
                                      Title: President


                                      /s/ Alastair McEwan
                                      -----------------------------------------
                                      Name:  Alastair McEwan
                                      Title: Vice President

                                      INVERESK RESEARCH (CANADA) INC.


                                      /s/ Walter Nimmo
                                      -----------------------------------------
                                      Name:  Walter Nimmo
                                      Title: President

                                      INVERESK RESEARCH GROUP LIMITED


                                      /s/ Walter Nimmo
                                      -----------------------------------------
                                      Name:   Walter Nimmo
                                      Title: Chief Executive Officer


                                      /s/ Stewart Leslie
                                      -----------------------------------------
                                      Name:  Stewart Leslie
                                      Title: Director and Company Secretary




                                      - 3 -
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.A.10
<SEQUENCE>2
<FILENAME>y46719a2ex99-a_10.txt
<DESCRIPTION>PRESS RELEASE
<TEXT>

<PAGE>   1
EXHIBIT 99(a)(10)



INVERESK ANNOUNCES EXPIRATION OF HART-SCOTT-RODINO WAITING PERIOD REGARDING
PENDING ACQUISITION OF CLINTRIALS RESEARCH INC., SCOTLAND, MARCH 20, 2001 -
Inveresk Research Group Limited announced the expiration of the waiting period
under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended,
applicable to Inveresk's pending acquisition of ClinTrials Research Inc.
(NASDAQ: CCRO). As previously announced, Inveresk Research Group Limited and
ClinTrials Research Inc. have entered into a merger agreement pursuant to which
an indirect wholly owned subsidiary of Inveresk, Indigo Acquisition Corp.,
commenced on March 5, 2001, a tender offer for all outstanding shares of common
stock of ClinTrials Research Inc. at an offer price of $6.00 per share, net to
the seller in cash. The offer is conditioned upon, among other things,
ClinTrials' shareholders tendering and not withdrawing prior to the expiration
of the offer at least a majority of the shares of ClinTrials' common stock,
calculated on a fully diluted basis. The tender offer and withdrawal rights are
scheduled to expire at 12:00 midnight, New York City time, on Monday, April 2,
2001, unless the offer is extended. The tender offer may be extended on the
terms and conditions stated in the Offer to Purchase, dated March 5, 2001, which
is available from the information agent for the offer: Morrow & Co., 445 Park
Avenue, 5th Floor, New York, New York 10022; (800) 654-2468 (bankers and
brokers); (800) 607-0088 (stockholders). Bear, Stearns & Co. Inc. ((888)
261-1668) is the dealer manager for the offer.

ClinTrials is a global contract research organization headquartered near
Research Triangle Park, North Carolina with offices in Maidenhead, England;
Glasgow, Scotland; Montreal, Canada; Brussels, Belgium; Paris, France;
Melbourne, Australia; Tel Aviv, Israel; Milan, Italy; Warsaw, Poland; Madrid,
Spain; and Munich, Germany. With more than 1,500 employees, ClinTrials provides
comprehensive research services, including monitoring, data management and
biostatistics, medical and regulatory services to pharmaceutical, biotechnology
and medical device clients.

Headquartered near Edinburgh, Scotland, Inveresk is a leading European provider
of contract research services, primarily to the pharmaceutical and biotechnology
industry.

THIS RELEASE CONTAINS FORWARD-LOOKING STATEMENTS, INCLUDING STATEMENTS ABOUT
FUTURE BUSINESS OPERATIONS, FINANCIAL PERFORMANCE AND MARKET CONDITIONS. SUCH
FORWARD-LOOKING STATEMENTS INVOLVE RISKS AND UNCERTAINTIES INHERENT IN BUSINESS
FORECASTS. THIS RELEASE IS NEITHER AN OFFER TO PURCHASE NOR A SOLICITATION OF AN
OFFER TO SELL SECURITIES OF CLINTRIALS RESEARCH INC. THE TENDER OFFER IS BEING
MADE SOLELY BY AN OFFER TO PURCHASE AND RELATED LETTER OF TRANSMITTAL
DISSEMINATED UPON THE COMMENCEMENT OF THE TENDER OFFER AND AMENDED FROM TIME TO
TIME. SHAREHOLDERS OF CLINTRIALS RESEARCH INC. SHOULD READ THE TENDER OFFER
STATEMENT BECAUSE IT CONTAINS IMPORTANT INFORMATION. THESE DOCUMENTS ARE
AVAILABLE TO CLINTRIALS SHAREHOLDERS AT NO CHARGE AND ARE ALSO AVAILABLE FOR
FREE AT THE SEC'S WEB SITE (HTTP://WWW.SEC.GOV).

CONTACT: GCI Christopher Gordon (212) 886-3428, ClinTrials Research, Inc. Paul
Ottaviano Chief Executive Officer (919) 460-9005

</TEXT>
</DOCUMENT>
</SUBMISSION>
