<SUBMISSION>
<ACCESSION-NUMBER>0001104659-05-020953
<TYPE>8-K
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20050505
<ITEMS>8.01
<FILING-DATE>20050506
<DATE-OF-FILING-DATE-CHANGE>20050505
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>AEROGEN INC
<CIK>0001039160
<ASSIGNED-SIC>3841
<IRS-NUMBER>330488580
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>8-K
<ACT>34
<FILE-NUMBER>000-31913
<FILM-NUMBER>05805285
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>2071 STIERLIN COURT
<CITY>MOUNTAIN VIEW
<STATE>CA
<ZIP>94043
<PHONE>650 864-7300
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2071 STIERLIN COURT
<CITY>MOUNTAIN VIEW
<STATE>CA
<ZIP>94043
</MAIL-ADDRESS>
</FILER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>a05-8890_18k.htm
<DESCRIPTION>8-K
<TEXT>
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<p style="border:none;margin:0in 0in .0001pt;padding:0in;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

</div>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">UNITED
STATES</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">SECURITIES
AND EXCHANGE COMMISSION</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Washington,
D. C.&nbsp; 20549</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">FORM 8-K</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">CURRENT REPORT</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="3" face="Times New Roman" style="font-size:12.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">Pursuant to Section&nbsp;13 or 15(d) of the</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="3" face="Times New Roman" style="font-size:12.0pt;font-weight:bold;">Securities Exchange Act of 1934</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Date of Report (Date of
earliest event reported):&nbsp;<b><font style="font-weight:bold;"> May 5, 2005</font></b></font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="5" face="Times New Roman" style="font-size:18.0pt;font-weight:bold;">AEROGEN,
INC.</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Exact name of registrant
as specified in its charter)</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Delaware</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(State or other
jurisdiction of incorporation)</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div align="center">

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">0-31913</font></b></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:2.0%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">33-0488580</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Commission File No.)</font></p>
  </td>
  <td width="2%" valign="bottom" style="padding:0in .7pt 0in .7pt;width:2.0%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="49%" valign="top" style="padding:0in .7pt 0in .7pt;width:49.0%;">
  <p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(IRS Employer
  Identification No.)</font></p>
  </td>
 </tr>
</table>

</div>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">2071
Stierlin Court, Suite 100</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Mountain
View, CA 94043</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">(Address of principal
executive offices and zip code)</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Registrant&#146;s telephone
number, including area code:<b><font style="font-weight:bold;">
(650)&nbsp;864-7300</font></b></font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;"> Written communications pursuant to Rule
425 under the Securities Act (17 CFR 230.425)</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;"> Soliciting material pursuant to Rule
14a-12 under the Exchange Act (17 CFR 240.14a-12)</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;"> Pre-commencement communications pursuant
to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Wingdings" style="font-size:10.0pt;">o</font><font size="2" style="font-size:10.0pt;"> Pre-commencement communications pursuant
to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))</font></p>

<div style="border:none;border-bottom:double windowtext 9.0pt;padding:0in 0in 0in 0in;">

<p style="border:none;margin:0in 0in .0001pt;padding:0in;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

</div>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<div style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">

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<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">Item&#160; 8.01 &#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Other
Items.</font></b></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;text-indent:.5in;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">On May 3, 2005, Aerogen (the &#147;Company&#148;) requested and
was granted an extension of time in which to file its plan of listing
qualification compliance with the Nasdaq Stock Market.&#160; The original submission deadline of May 4,
2005 has been extended to May 13, 2005.&#160;
The Company intends to submit a plan to achieve and sustain compliance
as requested by Nasdaq.</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">2</font></p>

<div style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">

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<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">SIGNATURE</font></b></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<table border="0" cellspacing="0" cellpadding="0" width="100%" style="border-collapse:collapse;width:100.0%;">
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="48%" colspan="5" valign="top" style="padding:0in .7pt 0in .7pt;width:48.68%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">AEROGEN</font></b><font size="2" style="font-size:10.0pt;">,<b><font style="font-weight:bold;">
  INC.</font></b></font></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="6%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:6.56%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="42%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:42.12%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:10.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Dated:&nbsp; May 5, 2005</font></p>
  </td>
  <td width="3%" valign="top" style="padding:0in .7pt 0in .7pt;width:3.92%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">By:</font></p>
  </td>
  <td width="28%" colspan="3" valign="top" style="border:none;border-bottom:solid windowtext 1.0pt;padding:0in .7pt 0in .7pt;width:28.86%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">/s/ Robert S. Breuil</font></p>
  </td>
  <td width="15%" valign="top" style="padding:0in .7pt 0in .7pt;width:15.9%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="6%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:6.56%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Name:</font></p>
  </td>
  <td width="42%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:42.12%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Robert S. Breuil</font></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><b><font size="2" face="Times New Roman" style="font-size:1.0pt;font-weight:bold;">&nbsp;</font></b></p>
  </td>
  <td width="5%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:5.24%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Title:</font></p>
  </td>
  <td width="43%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:43.44%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">Chief Financial Officer and Vice</font></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="5%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:5.24%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:1.0pt;">&nbsp;</font></p>
  </td>
  <td width="43%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:43.44%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">President of Corporate Development</font></p>
  </td>
 </tr>
 <tr>
  <td width="51%" valign="top" style="padding:0in .7pt 0in .7pt;width:51.32%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="6%" colspan="3" valign="top" style="padding:0in .7pt 0in .7pt;width:6.56%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
  <td width="42%" colspan="2" valign="top" style="padding:0in .7pt 0in .7pt;width:42.12%;">
  <p style="margin:0in 0in .0001pt;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>
  </td>
 </tr>
 <tr height="0">
  <td width="384" style="border:none;"></td>
  <td width="29" style="border:none;"></td>
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  <td width="196" style="border:none;"></td>
  <td width="119" style="border:none;"></td>
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<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">&nbsp;</font></p>

<p align="center" style="margin:0in 0in .0001pt;text-align:center;text-autospace:none;"><font size="2" face="Times New Roman" style="font-size:10.0pt;">3</font></p>

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