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        TO SECTION 13 OR 15(D) OF THE</strong></font></div>
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        EXCHANGE ACT OF 1934</strong></font></div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Date
        of
        Report (Date of earliest event reported):</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>
        February 24, 2006</strong></font></div>
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        Therapeutics, Inc.</strong></font></div>
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        name of registrant as specified in its charter)</font></div>
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                  File No.) </font></div>
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        Berry Street, Suite 6504</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>San
        Francisco, California 94107</strong></font></div>
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        telephone number, including area code:</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>
        (415) 512-7624</strong></font></div>
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        name or former address, if changed since last report) </font></div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">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:</font></div>
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</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Written
        communications pursuant to Rule 425 under the Securities Act (17 CFR
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</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Soliciting
        material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
        240.14a-12)</font></div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o
</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Pre-commencement
        communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
        240.14d-2(b))</font></div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Wingdings">o
</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Pre-commencement
        communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
        240.13e-4(c))</font><br></div><br>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM&#160;1.01</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ENTRY
        INTO A MATERIAL DEFINITIVE AGREEMENT</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">On
        Friday, February 24, 2006, the Company entered into an offer letter (the
&#8220;Offer
        Letter&#8221;) with Mr. Lutz Lingnau pursuant to which he joined the Board of
        Directors of the Company (the &#8220;Board&#8221;).</font></div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
        terms
        of the Offer Letter include (i) a yearly cash payment of $20,000 for each
        year
        of service on the Board, which payment may, at Mr. Lingnau&#8217;s option, be received
        as a fully-vested option to purchase shares of the Company&#8217;s common stock with a
        face value of $60,000; (ii) a payment of $1,000 for each Board or committee
        meeting attended in person and $500 for each Board or committee meeting attended
        by telephone; (iii) an initial option to purchase 30,000 shares of the Company&#8217;s
        common stock, vesting monthly over the first two years of service; and (iv)
        an
        option to purchase 10,000 shares of the Company&#8217;s common stock granted on each
        anniversary of continued service on the Board, vesting monthly over one year.
        The foregoing summary of the material terms of the Offer Letter is qualified
        in
        its entirety by reference to the full text of the Offer Letter, which will
        be
        filed as an exhibit to the Company&#8217;s Quarterly Report on Form 10-Q for the
        fiscal quarter ending March 31, 2006.</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Additionally,
        on Friday, February 24, 2006, the Company entered into an indemnification
        agreement (the &#8220;Indemnification Agreement&#8221;) with Mr. Lingnau in connection with
        his appointment to the Board. The terms of the Indemnification Agreement
        are
        identical in all material respects to the form of indemnification agreement
        that
        the Company has previously entered into with each of its directors and its
        Chief
        Executive Officer and include (i) indemnification to the fullest extent
        permitted by law against all expenses, liability and losses reasonably incurred
        or suffered by Mr. Lingnau in connection with any proceeding or action arising
        in connection with his service as a director of the Company; (ii) advancement
        of
        expenses incurred in connection with such proceeding or action (subject to
        repayment to the extent that Mr. Lingnau is ultimately determined not entitled
        to indemnification); (iii) coverage under the Company&#8217;s directors&#8217; and officers&#8217;
insurance policy; and (iv) a limitation on legal action asserted by or on
        behalf
        of the Company or its affiliates against Mr. Lingnau after the expiration
        of
        five (5) years from the date of accrual of such cause of action. The foregoing
        summary of the material terms of the Indemnification Agreement is qualified
        in
        its entirety by reference to the full text of the Indemnification Agreement,
        which will be filed as an exhibit to the Company&#8217;s Annual Report on Form 10-Q
        for the fiscal quarter ending March 31, 2006 and is incorporated herein by
        reference.</font><br></div>
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          <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
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      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM
        5.02</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>DEPARTURE
        OF DIRECTORS OR PRINCIPAL OFFICERS; ELECTION OF DIRECTORS; APPOINTMENT OF
        PRINCIPAL OFFICERS</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">On
        Friday, February 24, 2006, the Company appointed Mr. Lutz Lingnau to its
        Board.
        A copy of the press release issued by the Company on March 1, 2006 announcing
        Mr. Lingnau&#8217;s appointment to the Board is filed herewith as Exhibit 99.1 and is
        incorporated herein by reference.</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">In
        connection with his appointment, Mr. Lingnau entered into an Offer Letter
        and an
        Indemnification Agreement with the Company. The disclosures made in Item
        1.01
        above are hereby incorporated by reference into this Item 5.02.</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Mr.
        Lingnau, 63, retired from Schering AG Group, Germany, in 2005 as a member
        of
        Schering AG&#8217;s Executive Board and as Vice Chairman, President and Chief
        Executive Officer of Schering Berlin, Inc., a U.S. subsidiary. Prior to his
        retirement, Mr. Lingnau was responsible for Schering AG&#8217;s worldwide specialized
        therapeutics and dermatology businesses. He joined Schering AG&#8217;s business
        trainee program in 1966. Throughout his career at Schering AG, he served
        in
        various capacities and in a number of subsidiaries in South America and the
        United States, including as President of Berlex Laboratories, Inc., from
        1983 to
        1985, as the Head of Worldwide Sales and Marketing in the Pharmaceutical
        Division of Schering AG, from 1985 to 1989, and as Chairman of Berlex
        Laboratories, Inc. from 1985 to 2005. Mr. Lingnau is currently a member of
        the
        Supervisory Board of LANXESS AG. </font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Other
        than as described in Item 1.01 above, there have been no related party
        transactions between Mr. Lingnau and the Company. Mr. Lingnau has been appointed
        to the Compensation Committee of the Board of Directors of the
        Company.</font><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM
        8.01</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>OTHER
        EVENTS</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><em><u>Appointment
        of Chairman of the Board</u></em></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">On
        March
        1, 2006, the Company issued a press release announcing the appointment of
        Mr. R.
        Scott Greer as Chairman of the Board, replacing&#160;Dr. James Niedel, M.D.,
        Ph.D., who will remain on the Board. A copy of the press release is filed
        herewith as Exhibit 99.1 and is incorporated herein by reference. </font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><em><u>Board
        Committee Appointments</u></em></font></div>
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        connection with his appointment as Chairman of the Board, Mr. Greer has resigned
        as the Chairman of the Audit Committee, but will remain on the committee
        and
        continue as its financial expert. The composition of the Audit Committee
        is as
        follows: Dr. Bryan Roberts, Ph. D. (Chairman), Mr. Jeremy L. Curnock Cook
        and
        Mr. Greer. </font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Additionally,
        Mr. Greer has stepped down from the Compensation Committee. The composition
        of
        the Compensation Committee is as follows: Dr. Dennis Langer, M.D., J.D.
        (Chairman), Mr. Lingnau, Dr. Niedel and Dr. Roberts.</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
        composition of the Nominating and Corporate Governance Committee remains
        unchanged as follows: Dr. Douglas Fambrough, Ph.D. (Chairman), Mr. Cook and
        Dr.
        Niedel.</font><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM&#160;9.01</strong></font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>FINANCIAL
        STATEMENTS AND EXHIBITS</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>(d)
        Exhibits</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">99.1</font><font id="TAB2" style="COLOR: black; LETTER-SPACING: 27pt">&#160;</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Press
        Release issued by Sirna Therapeutics, Inc. on March 1, 2006.</font><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div><br>
      <div id="PGBRK" style="MARGIN-LEFT: 0pt; WIDTH: 100%; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
        <div id="FTR">
          <div style="WIDTH: 100%" align="left">
            <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
          </div>
          <div id="GLFTR" style="WIDTH: 100%" align="left">
          </div>
        </div>
        <div id="PN" style="PAGE-BREAK-AFTER: always">
          <div style="WIDTH: 100%; TEXT-ALIGN: center">
          </div>
          <div style="WIDTH: 100%; TEXT-ALIGN: center">
            <hr style="COLOR: black" noshade size="2">
          </div>
        </div>
        <div id="HDR">
          <div id="GLHDR" style="WIDTH: 100%" align="right">
          </div>
          <div style="WIDTH: 100%" align="left">
          </div>
        </div>
      </div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br>&#160;</div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>SIGNATURES</strong></font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 36pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Pursuant
        to the requirements of the Securities Exchange Act of 1934, as amended, the
        Registrant has duly caused this report to be signed on its behalf by the
        undersigned hereunto duly authorized. </font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Date:
        March 2, 2006</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
      <div>
        <table cellpadding="0" cellspacing="0" width="100%">

            <tr>
              <td align="left" valign="top" width="78%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">SIRNA
                  THERAPEUTICS, INC. </font></div>
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Registrant)
                  </font></div>
              </td>
            </tr>

        </table>
      </div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
      <div align="left">
        <table cellpadding="0" cellspacing="0" width="100%">

            <tr>
              <td align="left" valign="top" width="8%" style="border-bottom: #ffffff solid;">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">By:
                  </font></div>
              </td>
              <td valign="top" width="43%" style="border-bottom: black thin solid;">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">/s/
                  Gregory L. Weaver</font></div>
              </td>
              <td align="left" valign="top" width="40%" style="border-bottom: #ffffff solid;">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
            </tr>
            <tr>
              <td align="left" valign="top" width="8%" style="border-bottom: #ffffff solid;">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Name:
                  </font></div>
              </td>
              <td valign="top" width="43%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Gregory
                  L. Weaver</font></div>
              </td>
              <td align="left" valign="top" width="40%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
            </tr>
            <tr>
              <td align="left" valign="top" width="8%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Title:
                  </font></div>
              </td>
              <td valign="top" width="43%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Senior
                  Vice President and Chief Financial Officer</font></div>
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">(Principal
                  Financial and Accounting Officer)</font></div>
              </td>
              <td align="left" valign="top" width="40%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
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{"company-data": {"conformed-name": "SIRNA THERAPEUTICS INC", "cik": "0000892112", "assigned-sic": "2834", "irs-number": "341697351", "state-of-incorporation": "CO", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "8-K", "act": "34", "file-number": "000-27914", "film-number": "06660280"}, "business-address": {"street1": "2950 WILDERNESS PLACE", "city": "BOULDER", "state": "CO", "zip": "80301", "phone": "3034496500"}, "mail-address": {"street1": "2950 WILDERNESS PLACE", "city": "BOULDER", "state": "CO", "zip": "80301"}, "former-company": {"former-conformed-name": "RIBOZYME PHARMACEUTICALS INC", "date-changed": "19960306"}}
UNITED
        STATES
SECURITIES
        AND EXCHANGE COMMISSION
Washington,
        D.C. 20549
FORM
        8-K
CURRENT
        REPORT
PURSUANT
        TO SECTION 13 OR 15(D) OF THE
SECURITIES
        EXCHANGE ACT OF 1934
Date
        of
        Report (Date of earliest event reported):
February 24, 2006
Sirna
        Therapeutics, Inc.
(Exact
        name of registrant as specified in its charter)
Delaware
0-27914
34-1697351
(State
                  or other jurisdiction
of
                  incorporation)
(Commission
                  File No.)
(I.R.S.
                  Employer
Identification
                  Number)
185
        Berry Street, Suite 6504
San
        Francisco, California 94107
(Address
        of principal executive offices)
Registrant's
        telephone number, including area code:
(415) 512-7624
N/A
(Former
        name or former address, if changed since last report)
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:
o
Written
        communications pursuant to Rule 425 under the Securities Act (17 CFR
        230.425)
o
Soliciting
        material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
        240.14a-12)
o
Pre-commencement
        communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR
        240.14d-2(b))
o
Pre-commencement
        communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR
        240.13e-4(c))
ITEM 1.01
ENTRY
        INTO A MATERIAL DEFINITIVE AGREEMENT
On
        Friday, February 24, 2006, the Company entered into an offer letter (the
"Offer
        Letter") with Mr. Lutz Lingnau pursuant to which he joined the Board of
        Directors of the Company (the "Board").
The
        terms
        of the Offer Letter include (i) a yearly cash payment of $20,000 for each
        year
        of service on the Board, which payment may, at Mr. Lingnau's option, be received
        as a fully-vested option to purchase shares of the Company's common stock with a
        face value of $60,000; (ii) a payment of $1,000 for each Board or committee
        meeting attended in person and $500 for each Board or committee meeting attended
        by telephone; (iii) an initial option to purchase 30,000 shares of the Company's
        common stock, vesting monthly over the first two years of service; and (iv)
        an
        option to purchase 10,000 shares of the Company's common stock granted on each
        anniversary of continued service on the Board, vesting monthly over one year.
        The foregoing summary of the material terms of the Offer Letter is qualified
        in
        its entirety by reference to the full text of the Offer Letter, which will
        be
        filed as an exhibit to the Company's Quarterly Report on Form 10-Q for the
        fiscal quarter ending March 31, 2006.
Additionally,
        on Friday, February 24, 2006, the Company entered into an indemnification
        agreement (the "Indemnification Agreement") with Mr. Lingnau in connection with
        his appointment to the Board. The terms of the Indemnification Agreement
        are
        identical in all material respects to the form of indemnification agreement
        that
        the Company has previously entered into with each of its directors and its
        Chief
        Executive Officer and include (i) indemnification to the fullest extent
        permitted by law against all expenses, liability and losses reasonably incurred
        or suffered by Mr. Lingnau in connection with any proceeding or action arising
        in connection with his service as a director of the Company; (ii) advancement
        of
        expenses incurred in connection with such proceeding or action (subject to
        repayment to the extent that Mr. Lingnau is ultimately determined not entitled
        to indemnification); (iii) coverage under the Company's directors' and officers'
insurance policy; and (iv) a limitation on legal action asserted by or on
        behalf
        of the Company or its affiliates against Mr. Lingnau after the expiration
        of
        five (5) years from the date of accrual of such cause of action. The foregoing
        summary of the material terms of the Indemnification Agreement is qualified
        in
        its entirety by reference to the full text of the Indemnification Agreement,
        which will be filed as an exhibit to the Company's Annual Report on Form 10-Q
        for the fiscal quarter ending March 31, 2006 and is incorporated herein by
        reference.
ITEM
        5.02
DEPARTURE
        OF DIRECTORS OR PRINCIPAL OFFICERS; ELECTION OF DIRECTORS; APPOINTMENT OF
        PRINCIPAL OFFICERS
On
        Friday, February 24, 2006, the Company appointed Mr. Lutz Lingnau to its
        Board.
        A copy of the press release issued by the Company on March 1, 2006 announcing
        Mr. Lingnau's appointment to the Board is filed herewith as Exhibit 99.1 and is
        incorporated herein by reference.
In
        connection with his appointment, Mr. Lingnau entered into an Offer Letter
        and an
        Indemnification Agreement with the Company. The disclosures made in Item
        1.01
        above are hereby incorporated by reference into this Item 5.02.
Mr.
        Lingnau, 63, retired from Schering AG Group, Germany, in 2005 as a member
        of
        Schering AG's Executive Board and as Vice Chairman, President and Chief
        Executive Officer of Schering Berlin, Inc., a U.S. subsidiary. Prior to his
        retirement, Mr. Lingnau was responsible for Schering AG's worldwide specialized
        therapeutics and dermatology businesses. He joined Schering AG's business
        trainee program in 1966. Throughout his career at Schering AG, he served
        in
        various capacities and in a number of subsidiaries in South America and the
        United States, including as President of Berlex Laboratories, Inc., from
        1983 to
        1985, as the Head of Worldwide Sales and Marketing in the Pharmaceutical
        Division of Schering AG, from 1985 to 1989, and as Chairman of Berlex
        Laboratories, Inc. from 1985 to 2005. Mr. Lingnau is currently a member of
        the
        Supervisory Board of LANXESS AG.
Other
        than as described in Item 1.01 above, there have been no related party
        transactions between Mr. Lingnau and the Company. Mr. Lingnau has been appointed
        to the Compensation Committee of the Board of Directors of the
        Company.
ITEM
        8.01
OTHER
        EVENTS
Appointment
        of Chairman of the Board
On
        March
        1, 2006, the Company issued a press release announcing the appointment of
        Mr. R.
        Scott Greer as Chairman of the Board, replacing Dr. James Niedel, M.D.,
        Ph.D., who will remain on the Board. A copy of the press release is filed
        herewith as Exhibit 99.1 and is incorporated herein by reference.
Board
        Committee Appointments
In
        connection with his appointment as Chairman of the Board, Mr. Greer has resigned
        as the Chairman of the Audit Committee, but will remain on the committee
        and
        continue as its financial expert. The composition of the Audit Committee
        is as
        follows: Dr. Bryan Roberts, Ph. D. (Chairman), Mr. Jeremy L. Curnock Cook
        and
        Mr. Greer.
Additionally,
        Mr. Greer has stepped down from the Compensation Committee. The composition
        of
        the Compensation Committee is as follows: Dr. Dennis Langer, M.D., J.D.
        (Chairman), Mr. Lingnau, Dr. Niedel and Dr. Roberts.
The
        composition of the Nominating and Corporate Governance Committee remains
        unchanged as follows: Dr. Douglas Fambrough, Ph.D. (Chairman), Mr. Cook and
        Dr.
        Niedel.
ITEM 9.01
FINANCIAL
        STATEMENTS AND EXHIBITS
(d)
        Exhibits
99.1
Press
        Release issued by Sirna Therapeutics, Inc. on March 1, 2006.
SIGNATURES
Pursuant
        to the requirements of the Securities Exchange Act of 1934, as amended, the
        Registrant has duly caused this report to be signed on its behalf by the
        undersigned hereunto duly authorized.
Date:
        March 2, 2006
SIRNA
                  THERAPEUTICS, INC.
(Registrant)
By:
/s/
                  Gregory L. Weaver
Name:
Gregory
                  L. Weaver
Title:
Senior
                  Vice President and Chief Financial Officer
(Principal
                  Financial and Accounting Officer)