SECURITIES AND EXCHANGE COMMISSION
                             Washington, D. C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934
                                (Amendment No. 1)

                          ALNYLAM PHARMACEUTICALS, INC.
                          -----------------------------
                                (Name of Issuer)

                     Common Stock, $.01 par value per share
                     --------------------------------------
                         (Title and Class of Securities)

                                    02043Q107
                                    ---------
                                 (CUSIP Number)

                                December 31, 2007
                                -----------------
             (Date of Event which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this schedule
is filed:

         [x] Rule 13d-1(b)
         [ ] Rule 13d-1(c)
         [ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 (the "Act") or otherwise subject to the liabilities of that section of the
Act but shall be subject to all other provisions of the Act (however, see the
Notes).




CUSIP No. 02043Q107                                            Page 2 of 6 Pages

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1     NAMES OF REPORTING PERSONS
      S.S. OR I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS

      ALETHEIA RESEARCH AND MANAGEMENT, INC., IRS number 95-4647814, as general
      partner of various limited partnerships and on behalf of various managed
      accounts.

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2     CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP                  (a) [  ]
                                                                        (b) [  ]

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3     SEC USE ONLY

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4     CITIZENSHIP OR PLACE OF ORGANIZATION

      California
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                  5     SOLE VOTING POWER

                        2,748,469
    NUMBER OF     --------------------------------------------------------------
      SHARES      6     SHARED VOTING POWER
   BENEFICIALLY
     OWNED BY           0
       EACH       --------------------------------------------------------------
    REPORTING     7     SOLE DISPOSITIVE POWER
      PERSON
       WITH             2,748,469
                  --------------------------------------------------------------
                  8     SHARED DISPOSITIVE POWER

                        0
--------------------------------------------------------------------------------
9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

      2,748,469
--------------------------------------------------------------------------------
10    CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES* [ ]

--------------------------------------------------------------------------------
11    PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

      6.75%
--------------------------------------------------------------------------------
12    TYPE OF REPORTING PERSON*

      Aletheia Research and Management, Inc.- IA
--------------------------------------------------------------------------------


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CUSIP No. 02043Q107                                            Page 3 of 6 Pages

Item 1(a).        Name of Issuer:

                  Alnylam Pharmaceuticals, Inc.

Item 1(b).        Address of Issuer's Principal Executive Offices:

                  300 Third Street, Cambridge, MA 02142

Item 2(a).        Name of Person Filing:

                  Aletheia Research and Management, Inc.

Item 2(b).        Address of Principal Business Office or, if None, Residence:

                  100 Wilshire Boulevard, Suite 1960, Santa Monica, CA  90401

Item 2(c).        Citizenship:

                  Not Applicable.

Item 2(d).        Title of Class of Securities:

                  Common Stock, $.01 par value.

Item 2(e).        CUSIP Number:

                  02043Q107

Item 3.           If this statement is filed pursuant to Rule 13d-1(b), or
                  13d-2(b) or (c), check whether the person filing is a:

             (a)  [ ]   Broker or Dealer registered under Section 15 of the Act.

             (b)  [ ]   Bank as defined in Section 3(a)(6) of the Act.

             (c)  [ ]   Insurance Company as defined in Section 3(a)(19) of the
                        Act.

             (d)  [ ]   Investment Company registered under Section 8 of the
                        Investment Company Act.

             (e)  |X|   Investment Adviser registered in accordance with Rule
                        13d-1(b)(1)(ii)(E).


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CUSIP No. 02043Q107                                            Page 4 of 6 Pages

             (f)  [ ]   Employee Benefit Plan or Endowment Fund in accordance
                        with Rule 13d-1(b)(1)(ii)(F).

             (g)  [ ]   Parent Holding Company or control person in accordance
                        with Rule 13d-1(b)(1)(ii)(G).

             (h)  [ ]   A savings association as defined in Section 3(b) of the
                        Federal Deposit Insurance Act.

             (i)  [ ]   A church plan that is excluded from the definition of an
                        investment company under Section 3(c) (14) of the
                        Investment Company Act of 1940.

             (j)  [ ]   Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

                        If this Statement is filed pursuant to Rule 13d-1(c),
                        check this box [ ].

Item 4.           Ownership.

                  (a) Amount beneficially owned: 2,748,469*

                  (b) Percent of Class: 6.75%

                  (c) Number of Shares as to which the person has:

                        (i)   Sole power to vote or to direct the vote:
                              2,748,469

                        (ii)  Shared power to vote or to direct the vote: 0

                        (iii) Sole power to dispose or to direct the disposition
                              of: 2,748,469

                        (iv)  Shared Power to dispose or to direct the
                              disposition of: 0

                  * See Disclaimer of Beneficial Ownership

Item 5.           Ownership of Five Percent or Less of a Class.

             If this statement is being filed to report the fact that as of
the date hereof the reporting person has ceased to be the beneficial owner of
more than five percent of the class of securities, check the following. [ ].

Item 6            Ownership of More than Five Percent on Behalf of Another
                  Person.

                  Various accounts and funds managed by the reporting person
                  have the right to receive or the power to direct the receipt
                  of dividends from, or the proceeds from the sale of, the
                  securities held in their respective accounts. To the knowledge
                  of the reporting person, the interest of any one such account
                  does not exceed 5% of the class of securities.

Item 7.           Identification and Classification of the Subsidiary Which
                  Acquired the Security Being Reported on by the Parent Holding
                  Company.

                  Not Applicable.


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CUSIP No. 02043Q107                                            Page 5 of 6 Pages

Item 8.           Identification and Classification of Members of the Group.

                  Not Applicable

Item 9.           Notice of Dissolution of Group.

                  Not Applicable.

Item 10.          Certification.

                  By signing below, I certify that, to the best of my knowledge
                  and belief, the securities referred to above were not acquired
                  and are not held for the purpose of or with the effect of
                  changing or influencing the control of the issuer of the
                  securities and were not acquired and are not held in
                  connection with or as a participant in any transaction having
                  that purpose or effect.

                                    SIGNATURE

Date: February 11, 2008         ALETHEIA RESEARCH AND MANAGEMENT, INC.,


                                          By: /s/ Roger Peikin
                                              --------------------------------
                                              Name: Roger Peikin
                                              Title: Executive Vice-President


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                                                                       EXHIBIT A

                       DISCLAIMER OF BENEFICIAL OWNERSHIP

Alnylam Pharmaceuticals, Inc.
Common Stock
2,748,469 shares

Aletheia Research and Management, Inc. ("Aletheia") is an investment advisor
registered under Section 203 of the Investment Advisors Act of 1940 and serves
in such capacity for a number of managed accounts and funds. In its role as an
investment advisor or manager, Aletheia possesses investment and/or voting power
over the securities of the Issuer discussed in this schedule. Aletheia disclaims
beneficial ownership of such securities. In addition, the filing of this
Schedule 13G shall not be construed as an admission that the reporting person or
any of its affiliates is the beneficial owner of any securities covered by this
Schedule 13G for any purposes other than Section 13(a) of the Securities
Exchange Act of 1934.


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