<PAGE>
                                                                  Exhibit 10.35


                   AMENDMENT TO AGREEMENT AND PLAN OF MERGER

     This Amendment to the Agreement and Plan of Merger (the "Amendment"), dated
as of April 29, 2002, is by and among Alkermes, Inc., a Pennsylvania corporation
("Alkermes"), New Alkermes, Inc., a Pennsylvania corporation ("Parent"), Adams
Acquisition Sub, Inc., a Pennsylvania corporation and a wholly owned subsidiary
of Parent ("Adams Acquisition Sub"), Revere Acquisition Sub, LLC, a Delaware
limited liability company and a wholly owned subsidiary of Parent ("Revere
Acquisition Sub"), and Reliant Pharmaceuticals, LLC, a Delaware limited
liability company ("Reliant"), and amends the Agreement and Plan of Merger dated
March 20, 2002 between such Parties (the "Merger Agreement"). All capitalized
terms used in this Amendment without definition have the respective meanings set
forth in the Merger Agreement.

     WHEREAS, the Parties desire to amend the terms and provisions of the Merger
Agreement to change the definition of "Alkermes-Owned Reliant Units" used
therein for the purpose of including in such definition any Reliant Units owned
by Versant Acquisition LLC, a wholly owned subsidiary of Alkermes, and providing
that any such Reliant Units will be converted into Common Units immediately
following the Alkermes Merger Effective Time, but shall be otherwise unaffected
and shall continue to exist and remain outstanding as common units of Reliant
Surviving LLC after the Reliant Merger Effective Time; and

     WHEREAS, the Parties desire to amend Section 10.5 of the Merger Agreement
to clarify the intent of the Parties.

     NOW THEREFORE, the Parties, intending to be legally bound, agree as
follows:

     1.  Alkermes-Owned Reliant Units.

     (a) Section 2.2(b) of the Merger Agreement is hereby amended and restated
to be and read in full as follows:

          "(b) Alkermes-Owned Reliant Units.  All Reliant Units owned by
     Alkermes or any Subsidiary of Alkermes, including Versant Acquisition LLC,
     immediately prior to the Reliant Merger Effective Time (the "Alkermes-Owned
     Reliant Units") shall, together with all other Preferred Units, be
     converted into Common Units immediately prior to the Reliant Merger
     Effective Time, but the Common Units into which such Alkermes-Owned Reliant
     Units are converted shall be otherwise unaffected and shall continue to
     exist and remain outstanding as common units of Reliant Surviving LLC after
     the Reliant Merger Effective Time. No Parent Common Stock or other
     consideration shall be delivered to Alkermes or any of its Subsidiaries in
     respect of the Alkermes-Owned Reliant Units."

     (b) Section 2.2(c) of the Merger Agreement is hereby amended and restated
to be and read in full as follows:

          "(c) Conversion of Reliant Units.  Subject to Section 2.3(e), each
     issued and outstanding Reliant Unit (other than the Alkermes-Owned Reliant
     Units), including Reliant Restricted Units, shall be converted into the
     right to receive 1.3297 (the "Reliant Exchange Ratio") validly issued,
     fully paid and non-assessable shares of Parent Common Stock (the "Reliant
     Merger Consideration" and, together with the Alkermes Merger Consideration,
     the "Merger Consideration"). As of the Reliant Merger Effective Time, all
     Reliant Units (other than the Alkermes-Owned Reliant Units) shall no longer
     be outstanding and shall automatically be canceled and retired and shall
     cease to exist, and each holder (other than Alkermes or any Subsidiary of
     Alkermes, including Versant Acquisition LLC) of a Reliant Unit immediately
     prior to the Reliant Merger Effective Time shall cease to have any rights
     with respect thereto, except the right to receive the Reliant Merger
     Consideration, and any dividends or other distributions to which such
     holder is entitled pursuant to Section 2.3(d) and cash in lieu of
     fractional shares of Parent Common Stock to which a holder of such Reliant
     Units is entitled pursuant to Section 2.3(f), in each case to be issued or
     paid in accordance with Section 2.3(c), without interest. All shares of
     Parent Common Stock constituting the Reliant Merger Consideration shall be
     deemed to have been issued as of the Reliant Merger Effective Time."


<PAGE>

     2.  Versant Merger.  The Parties hereby acknowledge that, in accordance
with and subject to the terms of the Agreement and Plan of Merger, dated April
29, 2002 (the "Versant Merger Agreement"), among Alkermes, Parent, Versant
Acquisition LLC and Versant Reliant Corporation ("Versant"), immediately after
the Alkermes Merger Effective Time and immediately prior to the Reliant Merger
Effective Time, Versant will merge with and into Versant Acquisition LLC, with
Versant Acquisition LLC as the survivor, and the stockholders of Versant shall
receive, based upon their equity ownership of Versant, the shares of Parent
Common Stock that Versant, in its capacity as a member of Reliant, would have
received in the Reliant Merger in accordance with the provisions of Section
2.2(c) of the Merger Agreement.

     3.  Section 10.5.  Section 10.5 of the Merger Agreement is amended and
restated to be and read in full as follows:

          "Absent fraud, after Closing, the indemnification rights provided in
     this Article X, including the Escrow Indemnity Agreement and the Tax
     Indemnity Agreement, shall be the sole and exclusive remedy available to
     the Alkermes Indemnified Parties for any breach or alleged breach of this
     Agreement by Reliant."

     4.  Miscellaneous.

     (a) Governing Law.  This Amendment shall be governed by the laws of the
         State of Delaware (without giving effect to the conflict of laws
         provisions thereof).

     (b) Successors and Assigns.  This Amendment shall be binding upon and inure
         to the benefit of the Parties and their respective heirs, successors
         and permitted assigns. Nothing in this Amendment, express or implied,
         shall be construed to confer any rights or remedies upon any Person
         other than the Parties hereto, their respective successors and
         permitted assigns, Versant Acquisition LLC and as provided in Section
         12.4 of the Merger Agreement.

     (c) Further Assurances.  Each Party agrees to execute, acknowledge and
         deliver such further instruments and to do all such other acts as may
         be reasonably necessary or appropriate in order to carry out the
         purposes and intent of this Amendment.

     (d) Ratification.  Except as expressly modified by this Amendment, the
         terms and provisions of the Merger Agreement shall remain in full force
         and effect. If there is any conflict between the provisions of the
         Merger Agreement and the provisions of this Amendment, the provisions
         of this Amendment shall control.

     (e) Amendments.  This Amendment may be changed, modified or amended only by
         an agreement in writing signed by the Parties hereto.

     (f)  Counterparts.  This Amendment may be executed in counterparts, each of
          which shall be deemed an original, and all of which together shall
          constitute one and the same instrument.

                      [Signatures on the following page.]

                                       2
<PAGE>

     IN WITNESS WHEREOF, the Parties' duly authorized representatives have
executed and delivered this Amendment to the Merger Agreement as of the date and
year first above written.

                                          ALKERMES, INC.

                                          By:      /s/ JAMES M. FRATES
                                            ------------------------------------
                                          Name: James M. Frates
                                          Title:   Vice President and Chief
                                          Financial Officer

                                          NEW ALKERMES, INC.

                                          By:      /s/ JAMES M. FRATES
                                            ------------------------------------
                                          Name: James M. Frates
                                          Title:   Vice President

                                          ADAMS ACQUISITION SUB, INC.

                                          By:      /s/ JAMES M. FRATES
                                            ------------------------------------
                                          Name: James M. Frates
                                          Title:   Vice President

                                          REVERE ACQUISITION SUB, LLC

                                          By:      /s/ JAMES M. FRATES
                                            ------------------------------------
                                          Name: James M. Frates
                                          Title:   Vice President

                                          RELIANT PHARMACEUTICALS, LLC

                                          By:    /s/ JOSEPH J. KRIVULKA
                                            ------------------------------------
                                          Name: Joseph J. Krivulka
                                          Title:   President
Solely in their role as Reliant Member
Representatives:

By:      /s/ FREDERICK CRAVES
    ----------------------------------
Frederick Craves, not individually,
but solely
in his capacity as a Reliant Member
Representative

By:      /s/ MARK HOPLAMAZIAN
--------------------------------------
Mark Hoplamazian, not individually,
but solely
in his capacity as a Reliant Member
Representative

                                      3