<html>
  <head>
    <title>
</title>
</head>
  <body bgcolor="#ffffff">
    <div><br>
      <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="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>UNITED
        STATES</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>SECURITIES
        AND EXCHANGE COMMISSION</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>Washington,
        D.C. 20549</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: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 16pt; FONT-FAMILY: Times New Roman"><strong>FORM
        8-K</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: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>CURRENT
        REPORT</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: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>PURSUANT
        TO SECTION 13 OR 15(D) OF THE</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>SECURITIES
        EXCHANGE ACT OF 1934</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: 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 22, 2006</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: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><font style="DISPLAY: inline; FONT-SIZE: 24pt; FONT-FAMILY: Times New Roman"><strong>Sirna
        Therapeutics, Inc.</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">(Exact
        name of registrant as specified in its charter)</font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div>
        <table cellpadding="0" cellspacing="0" width="100%">

            <tr>
              <td valign="top" width="23%">
                <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>Delaware
                  </strong></font></div>
              </td>
              <td align="left" valign="top" width="4%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
              <td valign="top" width="23%">
                <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>0-27914
                  </strong></font></div>
              </td>
              <td align="left" valign="top" width="4%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
              <td valign="top" width="23%">
                <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>34-1697351
                  </strong></font></div>
              </td>
            </tr>
            <tr>
              <td valign="top" width="23%">
                <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">(State
                  or other jurisdiction </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">of
                  incorporation) </font></div>
              </td>
              <td align="left" valign="top" width="4%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
              <td valign="top" width="23%">
                <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">(Commission
                  File No.) </font></div>
              </td>
              <td align="left" valign="top" width="4%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</div>
              </td>
              <td valign="top" width="23%">
                <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">(I.R.S.
                  Employer </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">Identification
                  Number)</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"><br></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>185
        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>
      <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">(Address
        of principal executive offices) </font></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></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">Registrant&#8217;s
        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>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="center"><br></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>N/A</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">(Former
        name or former address, if changed since last report) </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">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>
      <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: Wingdings">o
</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
        230.425)</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: Wingdings">o
</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>
      <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: 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>
      <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: 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></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
        <div id="FTR">
          <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>
        <div>&#160;</div>
      </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;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"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman"><strong>ITEM&#160;2.03</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>CREATION
        OF A DIRECT FINANCIAL OBLIGATION OR AN OBLIGATION UNDER AN OFF-BALANCE SHEET
        ARRANGEMENT OF A REGISTRANT</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
        Wednesday, February 22, 2006, Sirna Therapeutics, Inc. (the &#8220;Company&#8221;) entered
        into a lease agreement (the &#8220;Lease Agreement&#8221;) with Are-San Francisco No. 26,
        LLC (the &#8220;Landlord&#8221;) for the entire fourth floor (approximately 33,042 rentable
        square feet) and a portion of the fifth floor (approximately 3,714 rentable
        square feet) of a to-be-constructed building to be known as 1700 Owens Street,
        San Francisco, California. The target commencement date of the Lease Agreement
        is November 15, 2006, with an initial term of 84 months. The leased space
        will
        serve as the Company&#8217;s corporate headquarters as well as its research and
        development laboratory. <font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">The
        Company expects to substantially reduce lease expenses related to its Boulder,
        Colorado facilities as it transitions its headquarters and research and
        development operations to San Francisco. </font></font><br></div><BR>
      <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
        aggregate base rent under the Lease Agreement is as follows: Year 1 -
        $1,300,932; Year 2 - $1,502,749.44; Year 3 - $1,605,886.56; Years 4-7 - the
        base
        rent will be adjusted pursuant to an annual consumer price index specified
        in
        the Lease Agreement. In addition to the base rent, the Company will make
        lump
        sum payments to the Landlord of $222,500 on each of January 1, 2008 and January
        1, 2009. The Company will also be responsible for certain operating expenses,
        including taxes, capital repairs and improvements, property management and
        insurance. Pursuant to the terms of the Lease Agreement, the Company is required
        to deliver to the Landlord a security deposit in the amount of
        $889,029.</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
        foregoing summary of the material terms of the Lease Agreement is qualified
        in
        its entirety by reference to the full text of the Lease Agreement, to be
        attached as an exhibit to the Company&#8217;s Quarterly Report on Form 10-Q for the
        fiscal quarter ending March 31, 2006 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">
        <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="justify">&#160;</div>
        <div style="LINE-HEIGHT: 1.25" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Statements
          in the foregoing summary and in this Form 8-K generally that are not strictly
          historical are "forward-looking" statements, which should be considered
          as
          subject to many risks and uncertainties. For example, any anticipated reductions
          in expenses related to the Company's Boulder facilities arising as a result
          of
          the trans</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">ition</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">
          of the
          Company's headquarters and research and development operations to San Francisco
          are highly uncertain and subject to a number of significant variables and
          risks,
          including the potential adverse </font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">e</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">ffect
          of
          the trans</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">i</font><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">tion
          on
          employee retention and focus and the ability to manage operations during
          the
          overlapping period when facilities in both locations are open. Other risks
          and
          uncertainties include the Company's early stage of development and short
          operating history, whether the Company can achieve and maintain profitability,
          whether the Company can obtain and protect patents, the risk of third-party
          patent infringement claims, whether the Company can engage collaborators
          and
          obtain regulatory approval for products, the Company's concentration of
          stock
          ownership, and availability of materials for product manufacturing. These
          and
          additional risk factors are identified in the Company's Securities and
          Exchange
          Commission filings, including the Forms 10-K and 10-Q and in other SEC
          filings.
          The Company undertakes no obligation to revise or update any forward-looking
          statements in order to reflect events or circumstances that may arise after
          the
          date of this Form 8-K.</font></div>
        <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="justify">&#160;</div>
      </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
        5.03</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>AMENDMENTS
        TO ARTICLES OF INCORPORATION OR BYLAWS; CHANGE IN FISCAL
        YEAR</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
        February 22, 2006, the Company amended its Amended and Restated Bylaws by
        a
        resolution of the Board to increase the size of the Board to eight (8) and
        is
        incorporated herein by reference. The Amendment to the Company&#8217;s Bylaws is filed
        herewith as Exhibit 3.1. The Company&#8217;s Bylaws, as amended to date, 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">&#160;</div>
      <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
        <div id="FTR">
          <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>
        <div>&#160;</div>
      </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>
        <table align="center" border="0" cellpadding="0" cellspacing="0" id="hangingindent" width="100%">

            <tr valign="top" style="line-height: 1.25;">
              <td style="width: 36pt;">
                <div style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">3.1</font></div>
              </td>
              <td>
                <div style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt" align="left"><font style="DISPLAY: inline; FONT-SIZE: 10pt; FONT-FAMILY: Times New Roman">Amendment
                  to the Amended and Restated Bylaws of Sirna Therapeutics, Inc.,
                  effective
                  as of February 22, 2006</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"><br></div>
      <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left"><br></div>
      <div id="PGBRK" style="MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; MARGIN-RIGHT: 0pt">
        <div id="FTR">
          <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>
      </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="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:
        February 28, 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="6%" 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="27%" 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="6%">
                <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="27%">
                <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="6%">
                <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="27%">
                <div style="DISPLAY: block; MARGIN-LEFT: 0pt; TEXT-INDENT: 0pt; LINE-HEIGHT: 1.25; MARGIN-RIGHT: 0pt" align="left">&#160;</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>
  </body>
</html>
{"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": "06652376"}, "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 22, 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
ITEM 2.03
CREATION
        OF A DIRECT FINANCIAL OBLIGATION OR AN OBLIGATION UNDER AN OFF-BALANCE SHEET
        ARRANGEMENT OF A REGISTRANT
On
        Wednesday, February 22, 2006, Sirna Therapeutics, Inc. (the "Company") entered
        into a lease agreement (the "Lease Agreement") with Are-San Francisco No. 26,
        LLC (the "Landlord") for the entire fourth floor (approximately 33,042 rentable
        square feet) and a portion of the fifth floor (approximately 3,714 rentable
        square feet) of a to-be-constructed building to be known as 1700 Owens Street,
        San Francisco, California. The target commencement date of the Lease Agreement
        is November 15, 2006, with an initial term of 84 months. The leased space
        will
        serve as the Company's corporate headquarters as well as its research and
        development laboratory.
The
        Company expects to substantially reduce lease expenses related to its Boulder,
        Colorado facilities as it transitions its headquarters and research and
        development operations to San Francisco.
The
        aggregate base rent under the Lease Agreement is as follows: Year 1 -
        $1,300,932; Year 2 - $1,502,749.44; Year 3 - $1,605,886.56; Years 4-7 - the
        base
        rent will be adjusted pursuant to an annual consumer price index specified
        in
        the Lease Agreement. In addition to the base rent, the Company will make
        lump
        sum payments to the Landlord of $222,500 on each of January 1, 2008 and January
        1, 2009. The Company will also be responsible for certain operating expenses,
        including taxes, capital repairs and improvements, property management and
        insurance. Pursuant to the terms of the Lease Agreement, the Company is required
        to deliver to the Landlord a security deposit in the amount of
        $889,029.
The
        foregoing summary of the material terms of the Lease Agreement is qualified
        in
        its entirety by reference to the full text of the Lease Agreement, to be
        attached as an exhibit to the Company's Quarterly Report on Form 10-Q for the
        fiscal quarter ending March 31, 2006 and is incorporated herein by
        reference.
Statements
          in the foregoing summary and in this Form 8-K generally that are not strictly
          historical are "forward-looking" statements, which should be considered
          as
          subject to many risks and uncertainties. For example, any anticipated reductions
          in expenses related to the Company's Boulder facilities arising as a result
          of
          the trans
ition
of the
          Company's headquarters and research and development operations to San Francisco
          are highly uncertain and subject to a number of significant variables and
          risks,
          including the potential adverse
e
ffect
          of
          the trans
i
tion
          on
          employee retention and focus and the ability to manage operations during
          the
          overlapping period when facilities in both locations are open. Other risks
          and
          uncertainties include the Company's early stage of development and short
          operating history, whether the Company can achieve and maintain profitability,
          whether the Company can obtain and protect patents, the risk of third-party
          patent infringement claims, whether the Company can engage collaborators
          and
          obtain regulatory approval for products, the Company's concentration of
          stock
          ownership, and availability of materials for product manufacturing. These
          and
          additional risk factors are identified in the Company's Securities and
          Exchange
          Commission filings, including the Forms 10-K and 10-Q and in other SEC
          filings.
          The Company undertakes no obligation to revise or update any forward-looking
          statements in order to reflect events or circumstances that may arise after
          the
          date of this Form 8-K.
ITEM
        5.03
AMENDMENTS
        TO ARTICLES OF INCORPORATION OR BYLAWS; CHANGE IN FISCAL
        YEAR
On
        February 22, 2006, the Company amended its Amended and Restated Bylaws by
        a
        resolution of the Board to increase the size of the Board to eight (8) and
        is
        incorporated herein by reference. The Amendment to the Company's Bylaws is filed
        herewith as Exhibit 3.1. The Company's Bylaws, as amended to date, will be filed
        as an exhibit to the Company's Quarterly Report on Form 10-Q for the fiscal
        quarter ending March 31, 2006.
ITEM 9.01
FINANCIAL
        STATEMENTS AND EXHIBITS
(d)
        Exhibits
3.1
Amendment
                  to the Amended and Restated Bylaws of Sirna Therapeutics, Inc.,
                  effective
                  as of February 22, 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:
        February 28, 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)