Exhibit 10.47

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

                               Licensing Agreement

This  Agreement is made  effective  this 12th day of March 1999,  by and between
Integrated DNA  Technologies,  Inc., a corporation  organized and existing under
the laws of Iowa  having  offices  at 1710  Commercial  Park,  Coralville,  Iowa
(hereinafter  called "IDT"), and Hybridon,  Inc., a Delaware  corporation having
its principal place of business at 155 Fortune Boulevard, Milford, Massachusetts
01757 (hereinafter called "Hybridon").

WHEREAS, IDT owns or controls certain technology,  proprietary information,  and
inventions hereinunder described as IDT Antisense Technology,  and is willing to
grant a * * * License to Hybridon under the rights contained therein,  according
to the terms hereunder described; and

WHEREAS, Hybridon owns or controls certain technology,  proprietary information,
and inventions  hereinunder described as Hybridon Antisense  Technology,  and is
willing to grant a * * * License to IDT under  those  rights,  according  to the
terms hereunder described;

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

Section 1.  Definitions.

        For the  purpose of this  Agreement,  the  following  definitions  shall
apply.

        A.  "Affiliates" shall mean any corporation, company, partnership, joint
            venture or other  entity,  which  controls,  is  controlled or under
            common  control with Hybridon or IDT as the case may be, and, in the
            case of  Hybridon,  provided  such  entities  agree in writing to be
            bound by the terms and provisions of this Agreement, shall also mean
            and include MethylGene Inc., and OriGenix  Technologies Inc. For the
            purposes  of this  definition,  control  shall  mean the  direct  or
            indirect  ownership of at least fifty percent (50%) or, if less than
            fifty percent (50%), the maximum percentage as allowed by applicable
            law of (a) the stock  shares  entitled  to vote for the  election of
            directors; or (b) ownership interest.

        B.  "Chimeric Antisense Technology" shall mean any oligonucleotide,  the
            nucleotide   sequence  of  which  has  complementarity  for  and  is
            hybridizable to a nucleotide  sequence within RNA transcribed from a
            targeted gene, which  oligonucleotide  meets at least one of the two
            sets of criteria described in Appendix B attached hereto.

        C.  "Confidential  Information"  shall mean this Agreement,  and any and
            all books,  records,  opinions of counsel and  business  information
            required  to be  supplied  to either  Party  under the terms of this
            Agreement.


                                      - 1 -




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

        D.  "Hybridon  Antisense  Technology"  shall  mean all  Hybridon  issued
            patents, Hybridon filed patents applications, or patents acquired by
            Hybridon  as of or  prior  to  the  date  of  the  signing  of  this
            agreement, to the extent that the claims of such patents and patents
            issuing   from  such   applications   fall   within   the  scope  of
            oligonucleotides defined herein as Chimeric Antisense Technology.

        E.  "Hybridon Licensed Product" shall mean and include any material that
            either (a) is covered by a claim of any patent within the definition
            of Hybridon  Antisense  Technology;  or (b) the manufacture,  use or
            sale of which would constitute, but for the license granted pursuant
            to this  Agreement,  an  infringement  of any Valid Claim within the
            definition of Hybridon Antisense Technology.

        F.  "Hybridon  Sublicensed  Product" shall mean any IDT Licensed Product
            discovered  and/or  developed in whole or in part by Hybridon or its
            Affiliates,  which is sublicensed to a third party for  manufacture,
            development, distribution and/or commercialization.

        G.  "IDT Antisense  Technology" shall mean Chimeric Antisense Technology
            covered  by  one  or  more  Valid  Claims  of * * * * * *;  and  all
            divisional, reissues, and foreign counterparts claiming and entitled
            to the right of priority from these patents and patent applications.

        H.  "IDT Licensed Product" shall mean and include any material or method
            that either (a) is covered by a Valid Claim of any patent within the
            definition of IDT Antisense Technology; or (b) the manufacture,  use
            or sale of  which  would  constitute,  but for the  license  granted
            pursuant  to this  Agreement,  an  infringement  of any Valid  Claim
            within the definition of IDT Antisense Technology.

        I.  "Interference  Settlement Agreement" shall mean the Agreement signed
            by the parties to United States  Interference No. 104,041,  attached
            hereto as Attachment 1.

        J.  "License"  shall  mean  the  License  granted  to  Hybridon  and its
            Affiliates  for IDT Antisense  Technology  for Medical  Applications
            and/or the License  granted to IDT and its  Affiliates  for Hybridon
            Antisense Technology for Research Applications, as the case may be.

        K.  "Licensed Products" shall mean IDT Licensed Products and/or Hybridon
            Licensed Products, as the case may be.


                                      - 2 -




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


        L.  "Licensee" shall mean IDT and its Affiliates and/or Hybridon and its
            Affiliates, as the case may be.

        M.  "Licensor" shall mean IDT and its Affiliates and/or Hybridon and its
            Affiliates, as the case may be.

        N.  "Medical  Applications"  shall mean * * * * * * *, including without
            limitation, * * * * * * * * *.

        O.  "Net Sales"  shall mean the * * * * , from sales of * * * * * *: (i)
            import,  export,  excise, good and services,  sales or similar taxes
            and custom duties;  (ii) reasonable listed trade discounts,  rebates
            and   allowances,   as  well   as  all   returns;   (iii)   packing,
            transportation,   shipping,  insurance  and  other  similar  charges
            incurred in connection  with and  necessary  for  completion of such
            dispositions;  (iv)  *  *  *  *  * *  *;  and  (v)  *  * * * * *  *.
            Notwithstanding  the  foregoing,  * * * * * * * * *. For purposes of
            this Agreement,  a distributor will not * * * * * and sales by * * *
            * * * *.

        P.  "Research Applications" shall mean all * * * * * * including but not
            limited to * * * * * * *, with the exception of * * * * * * *.

        Q.  " Valid Claim"  shall mean a claim of an issued  patent that has not
            been  ruled  invalid  or  unenforceable  by  a  court  of  competent
            jurisdiction in an unappealed or unappealable decision.

Section 2.  Grants of Licenses

        A.  IDT License to Hybridon.

            IDT grants to Hybridon  and its  Affiliates,  a * * * * * License to
            make, use, offer to sell, import, and sell IDT Licensed Products for
            all Medical  Applications.  The License  granted to Hybridon and its
            Affiliates  shall  be  * *  *  **  *  according  to  the  terms  and
            restrictions as established in subsection 2C herein.

            (i) * * * * *. IDT shall * * * * *, including, but not limited to, *
                * * * *.

            (ii)* * * * *. IDT shall not * * * * *, with such licenses  having *
                * * * * than  those  established  herein,  unless * * * * *. IDT
                hereby * * * * * to make * * * * * to * * * * *, for any reason,
                including  but not  limited to: (1) * * * * *; (2) the * ** * *;
                and (3) any * * * * *. Under no circumstances shall* * * * * .


                                      - 3 -




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


       B.     Hybridon License to IDT.

              Hybridon  grants to IDT and its  Affiliates  * * * * * license  to
              use, manufacture, offer to sell, import and sell Hybridon Licensed
              Products for Research Applications.

              (i)    * * * * *. Hybridon shall * * * * *.

              (ii)   * * * * *. Hybridon shall not * * * * *, unless * * * * *.

              (iii)  License Clarified. Within sixty (60) days of the signing of
                     this  Agreement,  Hybridon  shall deliver to IDT a complete
                     list of  patents  and  patent  applications  owned by,  and
                     assigned or  exclusively  licensed to Hybridon  included in
                     the definition of Hybridon Antisense  Technology.  The list
                     shall be identified as Appendix A and will be  incorporated
                     into this Agreement upon acceptance by IDT.

       C.     Sublicenses.

              (i)    Upon grant of the license,  Hybridon and its Affiliates may
                     grant  written   sublicenses   to  third  parties  for  the
                     manufacture,     development,      distribution,     and/or
                     commercialization  of any IDT Licensed  Product  discovered
                     and/or  developed  in whole or in part by  Hybridon or such
                     Affiliates  (a Hybridon  Sublicensed  Product)  for Medical
                     Applications.  Hybridon  will inform IDT of the identity of
                     any  sublicensee  and the nature of such sublicense * * * *
                     *. Any agreement granting a sublicense shall state that the
                     sublicense  is  subject  to the  terms  of this  Agreement.
                     Hybridon  shall  have the  same  accounting  and  reporting
                     responsibilities for the activities of any sublicensee,  as
                     if the activities were directly those of Hybridon.

              (ii)   The Hybridon License to IDT and its Affiliates shall be * *
                     * * *.

Section 3.  Consideration.

       A.     Initial License Fee.

              Upon execution of this Agreement, Hybridon agrees to pay to* * * *
              * according to the following schedule:

              (i)    * * * * *;

              (ii)   * * * * *; and

              (iii)  * * * * *.


                                      - 4 -




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


       B.     * * * * *.

              (i)    * * * * *.  Hybridon  agrees  to  pay to * * * * * by or on
                     behalf  of  Hybridon,   its   Affiliates  or   sublicensees
                     hereunder, or its foreign equivalent.

                     Hybridon  shall  notify  *  * * *  *  ,  by  Hybridon,  its
                     Affiliates or sublicensees.

                     For  each * * * * *,  unless  compliance  with  the  notice
                     provisions of 3.B(iii) herein, allows for an extension.

              (ii)   * * * * *. Hybridon  agrees to pay to* * * * * or a foreign
                     equivalent.

                     For  each* * * * * ,  unless  compliance  with  the  notice
                     provisions of 3.B(iii) herein, allows for an extension.

                     Payment of the * * * * *, unless compliance with the notice
                     provisions of 3.B(iii) herein, allows for an extension.

              (iii)  Hybridon shall notify IDT * * * * *if Hybridon is unable to
                     * * * * * to IDT  for a * * * * * or an * * * * * sold by *
                     * * * * or * * * * *, within the time allotted in the above
                     numbered  sections  because  of * * * * * or * * * * * . In
                     such notification, Hybridon shall * * * * * . Hybridon will
                     make payment to IDT the* * * * * .

              Notwithstanding  the foregoing,  products developed  utilizing IDT
              Licensed Technology, but which products do not themselves infringe
              any Valid Claim, are* * * * *.

       C.     * * * * *

              (i)    In further  consideration  for the License  granted herein,
                     Hybridon agrees to pay to IDT the following* * * * * :

                     (1)    * * * * *,

                      * * * * *

                     (2)    * * * * *,

                      * * * * *

                      (3) * * * * * .


                                      - 5 -




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


              (ii)   IDT agrees to pay to Hybridon * * * * *.

                     Notwithstanding the foregoing, products developed utilizing
                     IDT or Hybridon Licensed Technology,  but which products do
                     not themselves infringe any Valid Claim, are * * * * *.

       D.     Accounting/Payments.

              (i)    For each  fiscal  year in which  there  are Net  Sales of a
                     Licensed Product, each Licensee shall prepare, or cause its
                     Affiliates or sublicensees  to prepare,  deliver and pay to
                     Licensor a  quarterly  estimate of the * * * * * due to the
                     Licensor under Section 3.D,* * * * *.

              (ii)   * * * * * *,  Licensee  shall prepare and deliver an annual
                     statement  of the total * * * * * due to  Licensor  for the
                     fiscal year  expired  under  Section  3.D.  Licensee  shall
                     tender payment of the balance owed for the year,  including
                     all  payments  owed  for the  fourth  quarter  of the  year
                     expired,  and any  necessary  adjustments  to the quarterly
                     estimate payments  previously paid. Each quarterly estimate
                     or annual  payment shall be  accompanied  by a report which
                     shall  indicate the  estimated or actual Net Sales,  as the
                     case may be, by Licensee for the previous  period and shall
                     show the amount of * * * * * due Licensor  with  sufficient
                     detail  to  enable  confirmation  of  the  calculations  by
                     Licensor.

              (iii)  Except as otherwise directed, all amounts owing to Licensor
                     under  this  Agreement  shall  be paid in U.S.  dollars  to
                     Licensor at the addresses  provided in Section 12(a). * * *
                     * * owing with  respect to Net Sales  stated in  currencies
                     other  than U.S.  dollars  shall be  converted  at the rate
                     shown in the  Federal  Reserve  Noon  Valuation  - Value of
                     Foreign Currencies on the day preceding the payment.

Section 4.  Recordkeeping.

       A.     Licensee,  its Affiliates and its sublicensee(s)  shall keep books
              and records  sufficient to verify the accuracy and completeness of
              Licensee's and its sublicensee(s)'s  accounting referred to above,
              including  without  limitation  sales,  accounts  receivable,  and
              invoice  records  relating  to IDT  Licensed  Products or Hybridon
              Licensed Products. Such books and records shall be preserved for a
              period not less than five years after they are created  during and
              after the term of this Agreement.


                                      - 6 -




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


       B.     Licensee,  its  Affiliates and its  sublicensee(s)  shall take all
              steps  necessary so that  Licensor  may,  within sixty days of its
              request,  review  and copy all the books and  records  at a single
              U.S.  location  to  verify  the  accuracy  of  Licensee's  and its
              sublicensee(s)'s  accounting.  Such review  shall be made not more
              than once each  fiscal  year,  upon  reasonable  notice and during
              regular  business hours, at the expense of Licensor by a certified
              public accountant to whom Licensee has no reasonable objection.

       C.     If a * * * * * * for a fiscal year is  determined,  Licensee,  its
              Affiliates or  sublicensee(s)  shall pay the * * * * * outstanding
              within thirty (30) days of receiving  written notice thereof,  and
              shall reimburse Licensor for the cost of the inspection.

Section 5.  Patent Prosecution and Maintenance Publications.

       A.     Prosecution and Maintenance.

              The  preparation,  filing,  prosecution,  and  maintenance  of all
              patents and patent  applications -- domestic,  international,  and
              foreign -- included in the definition of IDT Antisense Technology,
              shall remain the exclusive  responsibility of IDT. IDT retains the
              exclusive   right  and   authority  to  make  all   decisions  and
              determinations  regarding the prosecution and maintenance of those
              patents  and  patent   applications.   The  preparation,   filing,
              prosecution,   and   maintenance   of  all   patents   and  patent
              applications -- domestic, international and foreign -- included in
              the definition of Hybridon Antisense Technology,  shall remain the
              exclusive   responsibility  of  Hybridon.   Hybridon  retains  the
              exclusive   right  and   authority  to  make  all   decisions  and
              determinations  regarding the prosecution and maintenance of those
              patents and patent applications.

       B.     Patent Marking.

              Hybridon and IDT shall comply with all  applicable  United  States
              and foreign  jurisdiction  laws in respect of patent  marking,  if
              any.

       C.     Ownership.

              (i)    Acknowledgments.   All  patent   rights   and   proprietary
                     information  included  in IDT  Antisense  Technology  shall
                     remain the sole  property  of IDT.  All  patent  rights and
                     proprietary  information  included  in  Hybridon  Antisense
                     Technology shall remain the sole property of Hybridon.


                                      - 7 -




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


       D.     Infringement by Third Parties.

              In the event that either party believes there is  infringement  in
              that  party's  field  of use of any  patent  included  within  IDT
              Antisense  Technology or Hybridon Antisense  Technology under this
              Agreement,  that party  shall  provide the other party with prompt
              written notification  thereof.  During the term of this Agreement,
              the  Licensor of the patent  being  infringed  shall have the sole
              right, but not the obligation,  to bring and control any action or
              proceeding  at its own  expense  and by  counsel of its own choice
              against any such infringement. If the Licensor of the patent being
              infringed elects to prosecute such infringement, the total cost of
              any  infringement  action  shall be borne by the  Licensor and the
              Licensor shall keep any recovery or damages for past  infringement
              derived therefrom.

       E.     Infringement of Third Party Rights.

              (i)    In the  event  that  either  party  receives  notice  of or
                     believes there is infringement by Licensee,  or if there is
                     asserted  infringement  by  Licensee  of any third  party's
                     intellectual property  (collectively,  "Alleged Third Party
                     Rights") by reason of the manufacture, import, use, sale or
                     offer for sale of any product  arising out of IDT Antisense
                     Technology  or  Hybridon  Antisense  Technology,  the party
                     having knowledge of the alleged  infringement shall provide
                     the other party with prompt written  notification  thereof.
                     Licensee shall have the right to control any defense of any
                     claim of  infringement of Alleged Third Party Rights at its
                     own expense and any counsel of its choice.

              (ii)   In the event that  Licensee  incurs  any  costs,  attorneys
                     fees,  damage  awards,  or other  penalties  relating to an
                     alleged  or  proven  act of  infringement,  Licensee  shall
                     indemnify  and  hold  harmless  Licensor,  and  either  the
                     University of Iowa Research  Foundation/University of Iowa,
                     or the University of Massachusetts  Medical Center,  as the
                     case may be, for all such costs and expenses.

Section 6.  Limitation of Liability, Indemnification, Negation of Warranties.

       A.     Limitation of Liability.

              IDT shall not be liable to Hybridon, its Affiliates, sublicensees,
              successors,  or assigns for any loss of profits, loss of business,
              interruption   of   business,   nor  for   indirect,   special  or
              consequential  damages of any kind under this Agreement.  Hybridon
              shall  not  be  liable  to  IDT,  its  Affiliates,   sublicensees,
              successors,  or assigns for any loss of profits, loss of business,
              interruption   of   business,   nor  for   indirect,   special  or
              consequential damages of any kind under this Agreement.


                                      - 8 -




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


       B.     Patent Rights.

              The  parties  warrant  that  except as  otherwise  provided  under
              Section  10 of this  Agreement  with  respect  to U.S.  Government
              interests, each has the right to grant the Licenses granted to the
              other party in this  Agreement.  IDT warrants that it does not own
              or control  any  patents  or patent  applications  with  claims to
              antisense  compounds  and/or methods not already  disclosed in the
              definition of "IDT Antisense Technology."

       C.     No Warranties.

              Except as expressly  set forth  herein,  IDT and Hybridon  make no
              representations,  extend no warranties of any kind, either express
              or implied, and assume no responsibilities whatsoever with respect
              to use,  sale,  or  other  disposition  by  Hybridon,  IDT,  their
              Affiliates, sublicensees or their vendees or other transferees, of
              IDT Licensed Products or Hybridon Licensed Products, respectively.

              Except as expressly set forth herein,  nothing in this  Agreement,
              nor any prior communication, shall be construed as:

              (i)    a warranty or  representation  by IDT or Hybridon as to the
                     validity  or scope of any of the patents  contained  within
                     IDT Antisense Technology or Hybridon Antisense Technology;

              (ii)   a warranty or representation that anything made, used, sold
                     or otherwise disposed of under the Licenses granted in this
                     Agreement  will or  will  not  infringe  patents  of  third
                     parties; or

              (iii)  an  obligation  to furnish any know-how not provided in IDT
                     Antisense  Technology or Hybridon  Antisense  Technology or
                     any services other than those specified in this Agreement.

       D.     Indemnification.

              Hybridon  and IDT  shall  at all  times  during  the  term of this
              Agreement and thereafter,  indemnify,  defend and hold each other,
              the University of Iowa Research Foundation/University of Iowa, the
              University  of  Massachusetts  Medical  Center and the authors and
              inventors  of IDT  Antisense  Technology  and  Hybridon  Antisense
              Technology,  harmless  against all claims and expenses,  including
              legal expenses and reasonable  attorneys fees,  arising out of the
              death of or injury to any  person or  persons or out of any damage
              to  property  and  against any other  claim,  proceeding,  demand,
              expense and liability of any kind whatsoever resulting


                                      - 9 -




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


              from the production, manufacture, sale, use, lease, consumption or
              advertisement  of products or processes  arising from any right or
              obligation of IDT or Hybridon or any of its sublicensee(s) granted
              herein. Notwithstanding the above, each party at all times reserve
              the  right  to  retain  counsel  of its  own  to  defend  its  own
              interests.

       E.     Insurance.

              IDT  and  Hybridon   warrant  that  each  will  use   commercially
              reasonable  efforts  to  maintain  liability   insurance  coverage
              appropriate  to the risk  involved  in the sale and  marketing  of
              Licensed  Products,  and shall include in the  calculation of said
              risk, each parties'  responsibility for indemnification in Section
              6D herein.  Notwithstanding the above, failure to obtain liability
              insurance  for the sale of  research  products  by IDT or Hybridon
              shall not be a breach of this clause.

Section 7.  Confidential Information.

The following  provisions  relate to  restrictions  on the disclosure and use of
Confidential Information by the parties:

       A.     Confidentiality.   Hybridon  and  IDT  each  agrees  to  treat  as
              confidential  and to use only in the conduct of its business,  all
              Confidential Information disclosed to it by the other party.

       B.     Non-Disclosure  and  Non-Use.  Hybridon and IDT each agrees not to
              disclose any of the  Confidential  Information  received  from the
              other party to any unauthorized  third party and not to use any of
              the  Confidential  Information  except to fulfill the terms of the
              Agreement,  for a period of five (5) years from the receipt of the
              Confidential Information.

       C.     Release from Restrictions.  All information which is characterized
              as Confidential Information shall cease to be confidential and the
              receiving party shall be released from its respective  obligations
              under Sections 7A and 7B hereof if such information (a) is legally
              known to or was in the  possession of the  receiving  party at the
              time of the  disclosure;  (b) legally is or has become part of the
              public domain  through no act or omission of the receiving  party;
              (c) has been  disclosed to the  recipient by a third party without
              restriction as to the use or disclosure of the information; (d) is
              available  to the general  public as a result of a  governmentally
              required release or disclosure; or (e) is required to be disclosed
              by  the  laws,   regulations  or  otherwise  of  any  governmental
              authority,   including  without  limitation,  the  Securities  and
              Exchange  Commission and the U.S. Food and Drug  Administration as
              determined by counsel of the receiving or disclosing party.


                                     - 10 -




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


Section 8.  Term and Termination.

       A.     The word  "termination"  and  cognate  words  such as  "term"  and
              "terminate",  as used in this  Section 8,  whether  applied to the
              Agreement or an individual  License,  are to be read, except where
              the contrary is  specifically  indicated,  as omitting  from their
              effect the following  rights and  obligations,  all of which shall
              survive any  termination  to the degree  necessary to permit their
              complete fulfillment or discharge:

              (i)    Licensor's  right to  receive  or  recover  and  Licensee's
                     obligation  to pay * * * * * *  accrued  or  accruable  for
                     payment at the time of any termination.

              (ii)   Licensee's  obligation to maintain  records and  Licensor's
                     right to receive final year accounting  reports as provided
                     in Section 3.E.

              (iii)  Any  cause of action or claim of  Licensor,  accrued  or to
                     accrue because of any breach or default by the Licensee;

              (iv)   The  rights  and  obligations  of  both  parties  regarding
                     confidentiality as defined in Section 7 herein;

              (v)    The warranty,  indemnification and insurance  provisions as
                     set forth in Sections 6.C, 6.D and 6.E.

       B.     The term of this  Agreement  shall extend until the last patent to
              expire  included  within  IDT  Antisense  Technology  or  Hybridon
              Antisense Technology, whichever expires later.

       C.     In the event either party;

              (i)    shall  materially  breach any of the terms,  conditions and
                     agreements  contained in this Agreement,  including but not
                     limited  to failure to pay or make  corrected  payments  of
                     Royalties in a timely fashion; or

              (ii)   assigns or attempts to assign this  Agreement,  the License
                     or any interest herein or therein without the prior written
                     consent of the other party or except as otherwise permitted
                     in Section 9;

                     then the alleging  party may, at its  election,  notify the
                     other party of the alleged breach giving the other party 30
                     days' written notice to cure the breach or begin good faith
                     negotiations to resolve such alleged breach. If the alleged
                     breach is not resolved to the  satisfaction of the alleging
                     party  within  60 days of the first  giving  of notice  the
                     alleging party may,


                                     - 11 -




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

                     at its option, bring arbitration  proceedings under Section
                     11.D. In the event of a good faith  dispute about  monetary
                     obligations,  the  notified  party will pay any  undisputed
                     amounts to the alleging party and pay any disputed  amounts
                     into  escrow  pending  resolution  of  such  dispute,  with
                     payment to be made to the prevailing  party.  The * * * * *
                     licenses granted hereunder are not terminable except in the
                     event of bankruptcy of a Licensee and the continuing rights
                     of sublicensees and others under this Section 8.

       D.     IDT's Rights Should Hybridon Become Bankrupt.

              IDT shall have the right to  terminate  Hybridon's  License to IDT
              Antisense  Technology granted pursuant to this Agreement under the
              following circumstances:  (i) the admission by Hybridon in writing
              of its insolvency or bankruptcy, (ii) the making by Hybridon of an
              assignment  of  substantially  all its assets  for the  benefit of
              creditors, (iii) an application by Hybridon for the appointment of
              a trustee or receiver  for  Hybridon,  (iv) the  appointment  of a
              trustee  or  receiver  for  Hybridon,  (v) the  institution  by or
              against Hybridon of any bankruptcy,  reorganization,  arrangement,
              insolvency or  liquidation  proceedings or other  proceedings  for
              relief under any  bankruptcy  law or similar law for the relief of
              debtors which is allowed against  Hybridon,  or is consented to or
              is not dismissed,  stayed or otherwise nullified within sixty (60)
              days after the  institution  thereof,  or (vi) Hybridon  ceases to
              carry  on  business  as  a  going  concern.   Notwithstanding  the
              foregoing,   Hybridon  shall  have  the  right  to  grant  to  its
              sublicensee(s)   the  power  to  assume   Hybridon's   rights  and
              obligations  under its License  and its  Affiliates  shall  retain
              their  rights and  obligations  under this  Agreement,  limited to
              Hybridon  Sublicensed  Products.  Hybridon,  and its  successor in
              interest,  however  organized,  shall, to the extent  permitted by
              law,  maintain  in  full  IDT's  License  to  Hybridon   Antisense
              Technology  granted  pursuant  to  this  Agreement.  In  addition,
              subject to the foregoing,  if University of Massachusetts  Medical
              Center  ("UMMC")  terminates its license with Hybridon for certain
              Hybridon  Antisense  Technology  as a result of any of the  events
              listed in the first  sentence of this  paragraph,  UMMC shall have
              the right  for a period  of 180 days  after  said  termination  to
              assume the rights and obligations of Hybridon hereunder and within
              the first 180 days  thereafter  shall  have the right to assign or
              sublicense all rights and obligations of Hybridon hereunder to one
              and only one party (a "Subsequent Licensee") to whom UMMC regrants
              a  license  under  such  formerly  licensed   Hybridon   Antisense
              Technology. Such Subsequent Licensee shall have the same rights to
              sublicense  hereunder as Hybridon had prior to the  termination of
              its license hereunder.


                                     - 12 -




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

       E.     In the event IDT:

              (i)    shall  become   insolvent,   bankrupt  or  subject  to  the
                     provisions  of the  United  States  Bankruptcy  Code or any
                     other similar legislation of any jurisdiction, or makes any
                     assignment for the benefit of creditors, fails to generally
                     to pay its debts as they become due, is adjudged  bankrupt,
                     or otherwise acknowledges its insolvency,  or if a receiver
                     custodian  or trustee of IDT's  property or a major part of
                     IDT's property is appointed, or if any other proceeding for
                     relief  under any  bankruptcy  law or  similar  law for the
                     relief of debtors is instituted by or against IDT; or

              (ii)   ceases to carry on business as a going concern;

                     then  Hybridon  shall  have the  right to  terminate  IDT's
                     License to Hybridon  Antisense  Technology granted pursuant
                     to this  Agreement.  IDT,  and its  successor  in interest,
                     however organized,  shall maintain, to the extent permitted
                     by law,  the IDT  License to Hybridon  granted  pursuant to
                     this Agreement.

       F.     Waiver of Terms.  No waiver of any breach of any term or provision
              of this  Agreement  shall be effective  or binding  unless made in
              writing and signed by the party purporting to give the waiver.  No
              condoning,  excusing or waiver by any party of any default, breach
              or  non-observance  by the  other  party  at any  time or times in
              respect of any  covenant,  proviso or condition  contained  herein
              shall  operate  as  waiver of that  party's  rights  hereunder  in
              respect  of  any  continuing  or  subsequent  default,  breach  or
              non-observance, and no waiver shall be inferred from or implied by
              anything  done or  committed  to be done by the party having those
              rights.

       G.     Rights and Obligations after Termination.  Upon the termination of
              a  License  resulting  from  the  provisions  of 8.C,  8.D and 8.E
              herein,  the Licensee and its  sublicensee(s),  if any, shall have
              the  right,   within  six  (6)  months   following  such  date  of
              termination,  to sell or dispose of Licensed Products completed or
              substantially completed on the date of termination and to complete
              orders,  outstanding on such date of termination for such products
              pursuant to the terms of this Agreement.

       H.     Successors  in  Interest.  Should  IDT and/or  Hybridon,  or their
              assigns become insolvent, bankrupt or subject to the provisions of
              the United States Bankruptcy Code or any other similar legislation
              of any jurisdiction, the rights of the University of Iowa Research
              Foundation  and the  University of  Massachusetts  Medical  Center
              pertaining  to  retention,  reversion,  and/or  assumption  of the
              insolvent  parties interest in the patents  described herein shall
              not be  abrogated  in any  way by any  term or  provision  of this
              Agreement.


                                     - 13 -




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


Section 9.  Assignability.

       This Agreement may not be transferred or assigned by either party without
       the prior  written  consent of the other party,  except that Licensee may
       freely assign this Agreement to (i) an Affiliate,  if Licensee guarantees
       the full performance of its Affiliates' obligations hereunder, or (ii) an
       entity acquiring  substantially  all of Licensee's  business to which the
       License  relates.  Any  purported  assignment  in  contravention  of this
       section shall, at the option of the non-assigning party, be null and void
       and of no effect.

Section 10.  United States Government Interests.

       It is understood that if the United States Government (through any of its
       agencies or otherwise) has funded research, during the course of or under
       which any of the  inventions  of the patents  contained in a License were
       conceived or made, the United States Government is entitled,  as a right,
       under the provisions of 35 U.S.C. ss. 200-212 and applicable  regulations
       of  Chapter  37 of the Code of Federal  Regulations,  to a  nonexclusive,
       nontransferable,   irrevocable   paid-up  license  to  practice  or  have
       practiced  the  invention  of such patent for  government  purposes.  Any
       license  granted to Licensee in this  Agreement  shall be subject to such
       right.

Section 11.  Miscellaneous.

       A.     Applicable  Law. This  Agreement  shall be construed in accordance
              with the internal laws of the State of Illinois. If any provisions
              of this Agreement are or shall come into conflict with the laws or
              regulations of any jurisdiction or any governmental  entity having
              jurisdiction over the parties or this Agreement,  those provisions
              shall be deemed automatically deleted, if such deletion is allowed
              by relevant  law, and the remaining  terms and  conditions of this
              Agreement  shall  remain  in  full  force  and  effect.  If such a
              deletion  is not so  allowed or if such a  deletion  leaves  terms
              thereby made clearly  illogical or  inappropriate  in effect,  the
              parties agree to substitute  new terms as similar in effect to the
              present  terms  of this  Agreement  as may be  allowed  under  the
              applicable   laws  and   regulations.   The  parties   hereto  are
              independent contractors and not joint ventures or partners.

       B.     Construction/Effect.  The parties  acknowledge that this Agreement
              has been the  subject  of full  opportunity  for  negotiation  and
              amendment  and that the party  who has  taken the role of  drafter
              shall not suffer any adverse construction of any terms or language
              of this Agreement because of such role.

       C.     Force Majeure.  A party hereto shall not be deemed in default with
              respect  to the  performance  of or  compliance  with  the  terms,
              covenants,  agreements conditions or provisos of this Agreement if
              the failure to perform or comply


                                     - 14 -




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

              shall be due to any event of force majeure.  "Force majeure" shall
              include  natural  disasters,  acts of God,  or any other  event or
              cause beyond the control of the party claiming the benefit of this
              paragraph and which that party could not reasonably have protected
              itself  against,  provided  however  that  lack of funds or credit
              shall not constitute an event of force majeure.

       D.     Disputes-- Arbitration. The parties agree to attempt initially, to
              solve all claims,  disputes,  or controversies  arising under, out
              of, or in connection  with this Agreement by conducting good faith
              negotiations.  Except with  respect to disputes as to the validity
              of patents, applications for injunctions, specific performance, or
              other  equitable  relief,   any  dispute  arising  out  of  or  in
              connection   with  this   Agreement  or  any  legal   relationship
              associated  therewith,  that  cannot be  resolved  amicably by the
              parties, shall be finally resolved by arbitration. The arbitration
              shall be conducted in accordance with the arbitration rules of the
              American Arbitration  Association ("AAA") then in force, by one or
              more   arbitrators   appointed  in  accordance  with  said  rules;
              provided,   however,  that  arbitration  proceedings  may  not  be
              instituted  until the party  alleging  breach of this Agreement by
              the other party has given the other party not less than sixty (60)
              days' notice to remedy any alleged  breach and the other party has
              failed  to do so.  The  place of  arbitration  shall  be  Chicago,
              Illinois.  The award rendered shall be final and binding upon both
              parties.   The   judgement   rendered   shall   include  costs  of
              arbitration,  reasonable  attorney's fees and reasonable costs for
              any expert and other  witnesses.  The  arbitration  may  expressly
              consider the amounts paid  pursuant to Sections  3.B, 3.C and 3.D,
              in considering any claims of any damages.  Judgment upon the award
              may be entered in any court having  jurisdiction,  or  application
              may be made to such  court for  judicial  acceptance  of the award
              and/or an order of  enforcement.  Disputes  as to the  validity of
              patents   shall  be   resolved   by  the  courts  of   appropriate
              jurisdiction.

Section 12.  Notices.

       Any  notice  required  to be given  pursuant  to the  provisions  of this
       Agreement  shall be in writing  and shall be deemed to have been given at
       the earlier of the time when actually  received as a  consequence  of any
       effective method of delivery, including but not limited to hand delivery,
       transmission by telefax, or delivery by a professional courier service or
       the time when sent by  certified  or  registered  mail  addressed  to the
       party.  Any  notice of change of  address  shall be  effective  only upon
       actual receipt,  by the persons listed below or other formally authorized
       person(s) acting in their behalf.


                                     - 15 -




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


               (a)    Joseph A. Walder, M.D., Ph.D.
                      Integrated DNA Technologies, Inc.
                      President & CEO
                      1710 Commercial Park
                      Coralville, IA  52241-9802

               (b)    Cheryl M. Northrup, J.D.
                      Hybridon, Inc.
                      Vice President and General Counsel
                      155 Fortune Blvd
                      Milford, MA  01757

Section 13.  Integration.

       This agreement  constitutes  the full  understanding  between the parties
       with  reference  to the  subject  matter  hereof,  and no  statements  or
       agreements by or between the parties,  whether orally or in writing, made
       prior to or at the signing hereof, shall vary or modify the written terms
       of this Agreement. Neither party shall claim any amendment, modification,
       or release from any  provisions  of this  Agreement by mutual  agreement,
       acknowledgement,  or  otherwise,  unless  such  mutual  agreement  is  in
       writing, signed by the other party, and specifically states that it is an
       amendment to this Agreement.

Section 14.  Benefits.

       All terms and  provisions of this  Agreement  shall bind and inure to the
       benefit of the parties hereto,  and upon their respective  successors and
       assigns as those are permitted under the terms of this Agreement.

Section 15.  Contract Formation and Authority.

       The  persons  signing on behalf of IDT and  Hybridon  hereby  warrant and
       represent that they have authority to execute this Agreement on behalf of
       the party for whom they have signed.


                                     - 16 -




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



IN WITNESS WHEREOF,  the parties hereto have duly executed this Agreement on the
dates indicated below.


INTEGRATED DNA TECHNOLOGIES, INC.   HYBRIDON, INC.

/s/ Joseph A. Walder, M.D., Ph.D.           /s/ E. Andrews Grinstead III
- ---------------------------------           ----------------------------
Joseph A. Walder, M.D., Ph.D.                   E. Andrews Grinstead III
President                                       President

Date: March 15, 1999                        Date:   March 12, 1999
      ------------------------------                ----------------------------


                                     - 17 -




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


                                   APPENDIX B
                          Chimeric Antisense Technology

"Chimeric Antisense  Technology" shall mean any oligonucleotide,  the nucleotide
sequence of which has  complementarity  for and is  hybridizable to a nucleotide
sequence  within RNA  transcribed  from a targeted gene,  which  oligonucleotide
meets at least one set of the following two sets of criteria:

Criteria Set (1)

(a)    * * * * *; and

(b)    * * * * * ; and

(c)    * * * * *.

or:

Criteria Set (2)

(i)    * * * * *; and

(ii)   * * * * *; and

(iii)  * * * * *.


                                     - 18 -