EXHIBIT 3.6

  AMENDMENT TO BYLAWS OF IDEC PHARMACEUTICALS CORPORATION -- DECEMBER 21, 2001

         The Bylaws of the corporation are hereby amended as follows:

         1. Section 5 of Article II of the Bylaws is hereby amended and, as so
amended, restated to read in its entirety as follows:

                  "Section 5. Special meetings of the stockholders, for any
         purpose or purposes, unless otherwise prescribed by statue or by the
         certificate of incorporation, may only be called by the chief executive
         officer, the president or the Chairman of the Board and shall be called
         by the chief executive officer, the president or the secretary at the
         request in writing of a majority of the Board of Directors."

         2. Section 7 of Article III of the Bylaws is hereby amended and, as so
amended, restated to read in its entirety as follows:

                  "Section 7. Special meetings of the board may be called by the
         chief executive officer or the president on two (2) days' notice to
         each director by mail or forty-eight hours notice to each director
         either personally or by telegram; special meetings shall be called by
         the chief executive officer, the president or the secretary in like
         manner and on like notice on the written request of two directors
         unless the board consists of only one director, in which case special
         meetings shall be called by the president or secretary in like manner
         and on like notice on the written request of the sole director."

         3. Sections 1 through 10 of Article V of the Bylaws are hereby amended
and, as so amended, restated to read in their entirety as follows:

                                   "ARTICLE V

                                    OFFICERS

                  Section 1. The officers of the corporation shall be chosen by
         the Board of Directors and shall be a chief executive officer, a
         president, a chief financial officer and a secretary. The Board of
         directors may elect from among its members a Chairman of the Board and
         a Vice Chairman of the Board. The Board of Directors may also choose
         one or more vice-presidents, assistant chief financial officers and
         assistant secretaries. Any number of officers may be held by the same
         person, unless the certificate of incorporation or these bylaws
         otherwise provide.

                  Section 2. The Board of Directors at its first meeting after
         each annual meeting of stockholders shall choose a chief executive
         officer, a president, a chief financial officer and a secretary and may
         choose vice presidents.



                  Section 3. The Board of Directors may appoint such other
         officers and agents as it shall deem necessary who shall hold their
         offices for such terms and shall exercise such powers and perform such
         duties as shall be determined from time to time by the Board.

                  Section 4. The salaries of all officers and agents of the
         corporation shall be fixed by the Board of Directors.

                  Section 5. The officers of the corporation shall hold office
         until their successors are chosen and qualify. Any officer elected or
         appointed by the Board of Directors may be removed at any time by the
         affirmative vote of a majority of the Board of Directors. Any vacancy
         occurring in any office of the corporation shall be filled by the Board
         of Directors.

                            The Chairman of the Board

                  Section 6. The Chairman of the Board, if any, shall preside at
         all meetings of the Board of Directors and of the stockholders at which
         he shall be present. He shall have and may exercise such powers as are,
         from time to time, assigned to him by the Board and as may be provided
         by law.

                  Section 7. In the absence of the Chairman of the Board, the
         Vice Chairman of the Board, if any, shall preside at all meetings of
         the Board of Directors and of the stockholders at which he shall be
         present. He shall have and may exercise such powers as are, from time
         to time, assigned to him by the Board and as may be provided by law.

                           The Chief Executive Officer

                  Section 8. Subject to such supervisory powers, if any, as may
         be given by the Board to the Chairman of the Board, the chief executive
         officer shall preside at all meetings of the stockholders and in the
         absence of the Chairman of the Board, or if there be none, at all
         meetings of the Board, shall have general and active management of the
         business of the corporation and shall see that all orders and
         resolutions of the Board are carried into effect. He or she shall
         execute bonds, mortgages and other contracts requiring a seal, under
         the seal of the corporation, except where required or permitted by law
         to be otherwise signed and executed and except where the signing and
         execution thereof shall be expressly delegated by the Board to some
         other officer or agent of the corporation.

                        The President and Vice-Presidents

                  Section 9. The president shall, in the event there be no chief
         executive officer or in the absence of the chief executive officer or
         in the event of his or her disability or refusal to act, perform the
         duties of the chief executive officer, and when so acting, shall have
         the powers of and subject to all the restrictions upon the chief
         executive officer. The president shall perform such other duties and

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         have such other powers as may from time to time be prescribed for such
         person by the Board, the Chairman of the Board, the chief executive
         officer or these bylaws.

                  Section 10. The vice-president (or in the event there be more
         than one, the vice-presidents in the order designated by the directors,
         or in the absence of any designation, in the order of their election),
         shall, in the absence of the president or in the event of his or her
         disability or refusal to act, perform the duties of the president, and
         when so acting, shall have the powers of and subject to all the
         restrictions upon the president. The vice-president(s) shall perform
         such other duties and have such other powers as may from time to time
         be prescribed for by the Board, the president, the Chairman of the
         Board or these bylaws."

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