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                                                                    EXHIBIT 10.1

          Confidential materials omitted and filed separately with the
                       Securites and Exchange Commission.
                           Asterisks denote omissions.


                      AMENDMENT NO. 1 TO LICENSE AGREEMENT,
                        DATED AS OF FEBRUARY 21, 1990 AND
                        RESTATED AS OF SEPTEMBER 8, 1993,
                     BY AND BETWEEN THE WORCESTER FOUNDATION
                FOR BIOMEDICAL RESEARCH, INC. AND HYBRIDON, INC.

       This Agreement, dated as of November 26, 1996, is entered into by and
between the Worcester Foundation for Biomedical Research, Inc. (formerly the
Worcester Foundation for Experimental Biology, Inc.), having offices at 222
Maple Avenue, Shrewsbury, Massachusetts 01545, ("Foundation") and Hybridon, 
Inc., a Delaware Corporation having offices at One Innovation Drive, Worcester,
Massachusetts 01605, ("Hybridon").

                                   WITNESSETH:

       WHEREAS, Foundation and Hybridon entered into a license agreement, dated
as of February 21, 1990 and restated as of September 8, 1993 (the "License
Agreement"); and

       WHEREAS, Foundation and Hybridon wish to amend the License Agreement on
the terms set forth herein;

       NOW, THEREFORE, in consideration of the mutual covenants and agreements
set forth below, the parties agree as follows:

       1.     Capitalized terms used herein and not defined herein shall have
the respective meanings ascribed to such terms in the License Agreement.

       2.     Section 1.7 of the License Agreement shall be amended to read in
its entirety as follows:

       1.7.   SUBLICENSE INCOME. The term "Sublicense Income" shall mean all
              consideration received from Sublicensees of Licensee pursuant to
              Section 2.2(c), excluding (a) payments made by a Sublicensee in
              consideration for the issuance of equity or debt securities of
              Licensee, (b) payments made by a Sublicensee to support or fund
              research activities to be undertaken by Licensee, (c) up-front
              payments made in consideration or recognition of prior research
              and development efforts undertaken by Licensee, (d) payments made
              upon the achievement by Licensee or Sublicensee of specified
              milestones or benchmarks relating to the



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               Confidential materials omitted and filed separately
                   with the Securities and Exchange Commission.
                           Asterisks denote omissions.


              development of the Licensed Products sublicensed to Sublicensee,
              except to the extent that such payments are in consideration for
              the grant or exercise of a sublicense under the Patent Rights, and
              (e) payments made by a Sublicensee for the manufacture and supply
              of Licensed Products to such Sublicensee. If non-monetary
              consideration is so received, then a commercially reasonable
              monetary value will be assigned for purposes of calculating
              Foundation's share of Sublicense Income.

       3.     Section 5.2 of the License Agreement shall be amended to read in
its entirety as follows:

       5.2.   Royalties.
              ---------

              (a)    Except as provided in Section 5.2(b) below, on all sales of
              Licensed Products covered by any pending or Valid Claim of Patent
              Rights in any country where the Licensed Product is made, used or
              sold by Licensee or its Affiliates, Licensee shall pay Foundation
              royalties in accordance with the following schedule, such
              undertaking and schedule having been agreed to for the purpose of
              reflecting and advancing the mutual convenience of the parties:

                     (*)    ***** *********** *** ************ ******** *** **
                            *** **** ****;

                     (*)    ***** ********** ********* ** ** *** ***** *****;
 
                     (*)    ********** *********** *** ************ ********* 
                            ** ** *** ***** *****;

                     (*)    ********** ********** ********* ** ** *** *****
                            *****;
 
                     (*)    ************ ********* ** ** *** ***** ****** ***

                     (*)    ******** ******** *** *** ********** **** ** ***
                            ***** *****.
 

              For purposes of this Section 5.2, a "Valid Claim" shall mean a
              claim of an unexpired patent which shall not have been withdrawn,
              cancelled, or disclaimed, nor held invalid by a court of competent
              jurisdiction in any 



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               Confidential materials omitted and filed separately
                   with the Securities and Exchange Commission.
                           Asterisks denote omissions.


              unappealed or unappealable decision in the country where the
              Licensed Product is made, used or sold by Licensee or its
              Affiliates.

              (b)    Foundation shall *** ** ******** ** * ******* ** ***
              ******** **** ** ******** ** ** ********** for the ********** ***
              ****** ** ******** ******** ** **** *********** *** **********
              ***** ** **** ******** ******** if, and only if, *** *********
              received by ******** **** **** *********** ** *** **** of such
              ******** ******** ** **** *********** **** ********** ** ***
              ************ ** ***** ******* *****  ******* ***** **********
              ********** ******* *** at rates equal to or greater than those set
              forth in Section 5.2(a) (subject to any reduction pursuant to
              Section 5.8). **** ******* ** ******** ******* ************* **
              ******** *** * *********** **** *** *** *** ********** **** ***
              with respect to which Foundation shall ** ******** ** * ********
              pursuant to the first sentence of this Section 5.2(b), or **** ***
              *** ** ** ******** ** ******* ********* ***** *** *** ** ** ****
              *** ********* *********** ** ******** ********* ********** *****
              ** ******** ** * ******* ** *** ***** ** **** ******** ******** **
              **** *********** ** the applicable royalty rates set forth in
              Section 5.2(a) (subject to any reduction pursuant to Section
              5.8)***** ********** ******* ****** *** **** ** **** ***********
              *** ****** ** ********* ******** *** *** ******* ** *** ********
              ***** ******* ** *********** PROVIDED, HOWEVER, **** *** ********
              ***** *** ********** ******* ** ****** the agreement of such
              *********** ** ********* ******** *** *** ******* ** *** ********
              ***** ******** *** *** ** *** ***** **** ******** ***** ** ******
              such agreement **** **** ************ **** ******** ***** *** **
              ********** *** ******* ******** ** ******** *** ***** ***********
              *** *** *********** *** ****** ** ******** ******** ** ****
              *********** **** *** ** ****** ** ********** ***** ********* *****
              ** ************* *** ********* **** ******** ********* ** ** **
              ********* ****** **** ** ***** ** *** ******* ***** *******.

       4.     In all other respects the License Agreement shall remain in full
force and effect.



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       This Agreement may be executed in one or more counterparts, each of which
shall be deemed an original but all of which together shall constitute one and
the same instrument.

       IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed in their names by their properly and duly authorized officers or
representatives as of the date first written above.


WORCESTER FOUNDATION FOR                   HYBRIDON, INC.
BIOMEDICAL RESEARCH, INC.

By: /s/ Thoru Pederson                     By: /s/ E. Andrews Grinstead III
    ----------------------------               -------------------------------- 
    Name: Thoru Pederson                       Name: E. Andrews Grinstead III 
    Title: President & Director                Title: Chairman, President & CEO
    Date: 11/26/96                             Date: 11-13-96







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