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                                                                  EXECUTION COPY

                                                                    Exhibit 10.1

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

                   RESEARCH COLLABORATION AND OPTION AGREEMENT

                                 by and between

                                 HYBRIDON, INC.

                                       and

                   NOVARTIS INTERNATIONAL PHARMACEUTICAL LTD.

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                   RESEARCH COLLABORATION AND OPTION AGREEMENT

      This Research Collaboration and Option Agreement (this "Agreement") is
made this 31st day of May, 2005 (the "Effective Date") by and between Hybridon,
Inc., a Delaware corporation with principal offices at 345 Vassar Street,
Cambridge, Massachusetts 02139 ("Hybridon") and Novartis International
Pharmaceutical Ltd., a Bermuda corporation with principal offices at Hurst Holme
12, Trott Road, Hamilton, HM11 Bermuda ("Novartis"). Hybridon and Novartis are
sometimes referred to herein individually as a "Party" or collectively as the
"Parties."

      Capitalized terms used but not defined in this Agreement shall have the
meanings provided in the License, Development and Commercialization Agreement by
and between Hybridon and Novartis of even date herewith (the "License
Agreement").

                                  INTRODUCTION

      WHEREAS, Hybridon possesses expertise in discovering and developing novel
therapeutics based on IMO (as defined below) compounds;

      WHEREAS, Novartis and its Affiliates (as defined below) possess expertise
in discovering, developing, manufacturing, marketing and selling pharmaceuticals
worldwide;

      WHEREAS, the Parties desire to enter into a collaboration with the
objective of identifying IMO Candidates and generating IMO Leads (each of "IMO
Candidates" and "IMO Leads" as defined below) for use in the Research Field of
Use (the "Collaboration"); and

      WHEREAS, the Parties are entering into the License Agreement, pursuant to
which Novartis and its Affiliates shall have an exclusive license to
commercialize Products based on certain of the IMO Candidates in the Commercial
Field of Use upon the terms set forth in the License Agreement if Novartis
exercises its Commercialization Option hereunder (each of "Affiliates,"
"Commercial Field of Use," "Commercialization Option," "License Agreement,"
"Products," and "Research Field of Use" as defined below);

      NOW THEREFORE, in consideration of the mutual covenants set forth in this
Agreement, and other good and valuable consideration, the Parties agree as
follows:

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                                    ARTICLE I

                                   DEFINITIONS

      1.1. "ACCEPTANCE CRITERIA" shall mean the specifications for IMO
Candidates for acceptance into the CSP Phase set forth in the Research Plan.

      1.2. "ACQUISITION INTELLECTUAL PROPERTY" shall mean (a) Patents or
Know-How held or otherwise controlled by an Acquisition Affiliate immediately
prior to the Acquisition Event between Hybridon and such Acquisition Affiliate
(as defined in Section 1.3 below), other than Patents that do not specifically
relate to drug delivery or formulation technology held or otherwise controlled
by any such Acquisition Affiliate that would, but for a license granted
hereunder, be infringed by the development or commercialization of IMO
Candidates or IMO Leads and (b) Patents or Know-How developed or acquired and
controlled by an Acquisition Affiliate after the Acquisition Event between
Hybridon and such Acquisition Affiliate that specifically relate to drug
delivery or formulation technology, which Patents or Know-How are not developed
or acquired through the use of, or as an improvement to, any Hybridon
Intellectual Property or Hybridon Background Intellectual Property Controlled
(other than through an Acquisition Affiliate) by Hybridon.

      1.3. "ACQUISITION EVENT" shall mean any merger or other acquisition
between Hybridon and a Third Party occurring after the Effective Date and
pursuant to which such Third Party becomes an Affiliate of Hybridon, so long as
following such merger or acquisition Hybridon does not control and is not merged
with or into such Affiliate (an "Acquisition Affiliate").

      1.4. "ADDITIONAL INDICATION" shall have the meaning set forth in Section
4.1 of the License Agreement.

      1.5. "AFFILIATE" means any Person who directly or indirectly controls or
is controlled by or is under common control with a Party. For purposes of this
definition, "control" or "controlled" means ownership directly or through one or
more Affiliates, of fifty percent (50%) or more of the shares of stock entitled
to vote for the election of directors, in the case of a corporation, or fifty
percent (50%) or more of the equity interest in the case of any other type of
legal entity, status as a general partner in any partnership, or any other
arrangement whereby a

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Party controls or has the right to control the Board of Directors or equivalent
governing body of a corporation or other entity, or the ability to cause the
direction of the management or policies of a corporation or other entity. The
Parties acknowledge that in the case of certain entities organized under the
laws of certain countries outside of the United States, the maximum percentage
ownership permitted by law for a foreign investor may be less than fifty percent
(50%), and that in such case such lower percentage shall be substituted in the
preceding sentence, provided, that such foreign investor has the power to direct
the management and policies of such entity. For the purposes of this Agreement,
Novartis Institute for Functional Genomics, Inc. and Friedrich Miescher
Institute for Biomedical Research shall be deemed to be Affiliates of Novartis.

      1.6. "CHEMICALLY MODIFY" OR "CHEMICAL MODIFICATION" shall mean the
modification of an IMO that [**].

      1.7. "COLLABORATION" shall have the meaning set forth in the preamble to
this Agreement.

      1.8. "COMMERCIAL FIELD OF USE" shall mean the prophylaxis, palliation,
diagnosis and treatment of the Initial Indications and Additional Indications by
Products via any route of administration.

      1.9. "COMMERCIALIZATION EXERCISE NOTICE" shall have the meaning set forth
in Section 4.2.2 hereof.

      1.10. "COMMERCIALIZATION OPTION" shall have the meaning set forth in
Section 4.2.1 hereof.

      1.11. "CONFIDENTIAL INFORMATION" shall have the meaning set forth in
Section 5.1 hereof.

      1.12. "CONSUMER PRICE INDEX" shall mean the Consumer Price Index - Urban
Wage Earners and Clerical Workers, U.S. City Average, All Items, 1982-84 = 100,
published by the United States Department of Labor, Bureau of Labor Statistics
(or its successor equivalent index).

      1.13. "CONTROLLED" shall mean, with respect to intellectual property, the
legal authority of a Party (either directly or through an Affiliate) to grant
the licenses or sublicenses of

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intellectual property rights as and to the extent provided herein, or to
otherwise disclose proprietary or trade secret information as and to the extent
provided herein, without breaching the terms of any agreement with a Third
Party, knowingly infringing upon the intellectual property rights of a Third
Party, or misappropriating the proprietary or trade secret information of a
Third Party.

      1.14. "CRITICAL ISSUE" shall have the meaning set forth in Section 2.5.2
hereof.

      1.15. "CSP PHASE RESEARCH" shall have the meaning set forth in Section
2.3.2 hereof.

      1.16. "EFFECTIVE DATE" shall mean the effective date of this Agreement as
set forth on the first page hereof.

      1.17. "EPIGENESIS" shall mean EpiGenesis Pharmaceuticals, Inc.

      1.18. "EPIGENESIS AGREEMENT" shall mean that certain Development and
License Agreement, dated as of August 9, 2000, between Hybridon and EpiGenesis.

      1.19. "EXCLUDED ANTISENSE IP" shall mean oligonucleotides or
oligonucleotide analogs or mimics thereof that (a) are targeted to a specific
sequence of RNA and (b) the primary mechanism of action of which is to hybridize
to such sequence of RNA and through such hybridization to modulate the
production of the targeted gene product, provided, that such oligonucleotides or
oligonucleotide analogs or mimics thereof [**] proprietary to Hybridon[**].

      1.20. "EXTENDED RENEWAL PERIOD" shall have the meaning set forth in
Section 2.1.3 hereof.

      1.21. "FDA" shall mean the United States Food and Drug Administration, and
any successor agency serving the same function.

      1.22. "FPFV" shall mean the first visit of the first patient or first
healthy human volunteer participating in a clinical trial with respect to an IMO
Lead.

      1.23. "FTE" shall mean the equivalent of the work of one (1) Hybridon
scientist or other Hybridon project managerial professional, full time for one
year, which equates to a total of [**] weeks or [**] hours per year on or
directly related to the Research Program and shall exclude (a) managerial
activities (other than project and research management activities as

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described below) and (b) assistance with the manufacturing and supply activities
described in Sections 2.3.2(b) and 2.3.3(b) hereof. Work on or directly related
to the Research Program may include, but is not limited to, experimental
laboratory work, work related to Proof of Concept studies, project and research
management, activities directed toward evaluation of the commercial potential of
an IMO Candidate, recording and writing up results, reviewing literature and
references, holding scientific discussions, and carrying out JRC duties.

      1.24. "FTE RATE" shall mean a rate of [**] U.S. Dollars (U.S. $[**]) per
FTE, to be prorated on a daily basis if necessary (per annum amount to be
divided by [**] to produce the rate per whole day consisting of [**]). For the
avoidance of doubt, such rate shall include all travel expenses, which shall not
be invoiced separately. For each calendar year commencing with the 2007 calendar
year, the FTE Rate shall be subject to cost of living increases on an annual
basis, based on the increase in the Consumer Price Index as of the then most
recent December 31 over the Consumer Price Index on December 31, 2004, it being
understood that the FTE Rate to be used as the basis for each such increase, if
any, shall be $[**], and not the most recent FTE Rate then in effect.

      1.25. "HYBRIDON BACKGROUND INTELLECTUAL PROPERTY" shall mean all Patents
and Know-How Controlled by Hybridon as of the Effective Date or at any time
during the Term that are necessary or useful for the Parties or their Affiliates
or sublicensees to exploit the licenses contemplated or to carry out the
activities contemplated hereunder and that are not otherwise Hybridon
Intellectual Property or Joint Intellectual Property. Notwithstanding the
foregoing, "Hybridon Background Intellectual Property" shall exclude any
Acquisition Intellectual Property.

      1.26. "HYBRIDON INTELLECTUAL PROPERTY" shall mean all Hybridon Patents and
Hybridon Know-How, but explicitly excluding Joint Intellectual Property and any
Acquisition Intellectual Property.

      1.27. "HYBRIDON KNOW-HOW" shall mean all Know-How Controlled by Hybridon
relating to the IMO Candidates and IMO Leads but explicitly excluding Joint
Know-How and any Know-How included in the Acquisition Intellectual Property, as
of the Effective Date or at any time during the Term.

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      1.28. "HYBRIDON PATENTS" shall mean any Patents Controlled by Hybridon
that would, but for a license granted hereunder, be infringed by making, having
made, using, having used, researching, having researched, developing, having
developed, commercializing, having commercialized, manufacturing, having
manufactured, promoting, having promoted, selling, having sold, distributing,
having distributed, marketing, having marketed, importing, having imported,
exporting or having exported IMO Candidates or IMO Leads, but explicitly
excluding Joint Patents and any Patents included in the Acquisition Intellectual
Property, as in effect on the Effective Date or at any time during the Term. The
Hybridon Patents are set forth on Schedule 1.28 hereto, as amended from time to
time.

      1.29. "IMO" shall mean an immunomodulatory oligonucleotide containing a
motif proprietary to Hybridon and designed to agonize toll-like receptor 9
(directly or indirectly) for the primary purpose of inducing or modulating an
immune response.

      1.30. "IMO CANDIDATE" shall mean an IMO supplied by Hybridon in accordance
with Section 2.3.1(a) and that is designated by Novartis, in its sole
discretion, as meeting the Acceptance Criteria and for inclusion in the CSP
Phase Research.

      1.31. "IMO LEAD" shall have the meaning set forth in Section 2.3.2 hereof
and shall include any Improvements thereto. IMO Leads shall continue to be IMO
Candidates for purposes hereof.

      1.32. "IMPROVEMENTS" shall mean any enhancements to the formulation,
ingredients, preparations, presentation, means of delivery, dosage, packaging,
or manufacturing process of an IMO Lead, IMO Candidate or Product, but excluding
as to all of the foregoing any Chemical Modification to an IMO Lead, IMO
Candidate or the IMO Lead or IMO Candidate component of a Product. For the
avoidance of doubt, any salt form of an IMO Lead, IMO Candidate or IMO included
in a Product shall be deemed an Improvement for purposes hereof.

      1.33. "INDEMNIFIED PERSON" shall have the meaning set forth in Section 7.3
hereof.

      1.34. "INDEMNIFYING PARTY" shall have the meaning set forth in Section 7.3
hereof.

      1.35. "INITIAL INDICATIONS" shall mean all human allergic and/or
respiratory diseases, but specifically excluding oncology and infectious
diseases (other than cystic fibrosis, asthma

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and chronic obstructive pulmonary disease pathologies, in each case resulting
from infectious diseases) and systemic autoimmune diseases.

      1.36. "INITIAL RESEARCH TERM" shall have the meaning set forth in Section
2.1.1 hereof.

      1.37. "INVOICE" shall mean an invoice in the form attached hereto as
Schedule 1.37.

      1.38. "JOINT INTELLECTUAL PROPERTY" shall mean Joint Know How and Joint
Patents.

      1.39. "JOINT KNOW-HOW" shall mean all Know-How developed, produced, or
identified jointly by Hybridon and Novartis or their respective Affiliates
pursuant to the Research Program and/or under the Research Plan including, but
not limited to, such Know-How related to joint Improvements or to the
identification, generation, modification and/or characterization of IMO
Candidates and IMO Leads made jointly by the Parties.

      1.40. "JOINT PATENTS" shall mean all Patents for inventions conceived
jointly by Hybridon and Novartis or their respective Affiliates that arise out
of the activities performed under the Research Program including, but not
limited to, inventions relating to joint Improvements or to the identification,
generation, modification and/or characterization of IMO Candidates and IMO Leads
made jointly by the Parties. After the filing of the first Joint Patent, if any,
a list of Joint Patents shall be appended hereto as Schedule 1.40, which will be
updated periodically to reflect additional Joint Patents thereafter.

      1.41. "JRC" shall have the meaning set forth in Section 2.4 hereof.

      1.42. "KNOW-HOW" shall mean all data, technical information, material,
experience, know-how, inventions (whether or not patented), trade secrets,
processes and methods in any form discovered, developed or applied (with the
consent of its owner) and Controlled by either Party or its Affiliates,
excluding Patents.

      1.43. "LICENSE AGREEMENT" shall have the meaning set forth in the preamble
to this Agreement.

      1.44. "LOSS" shall have the meaning set forth in Section 7.1 hereof.

      1.45. "NOVARTIS INTELLECTUAL PROPERTY" shall mean all Novartis Patents and
Novartis Know-How, but explicitly excluding Joint Intellectual Property.

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      1.46. "NOVARTIS KNOW-HOW" shall mean all Know-How relating to
immunomodulatory oligonucleotides Controlled by Novartis on the Effective Date
or at any time during the Term, but explicitly excluding Joint Know-How,
Hybridon Intellectual Property and Hybridon Background Intellectual Property.

      1.47. "NOVARTIS PATENTS" shall mean any Patents relating to
immunomodulatory oligonucleotides Controlled by Novartis on the Effective Date
or at any time during the Term, but explicitly excluding Joint Patents, Hybridon
Intellectual Property and Hybridon Background Intellectual Property.

      1.48. "NOVARTIS RESEARCH LICENSE" shall have the meaning set forth in
Section 4.1.2 hereof.

      1.49. "OPTION TERM" shall mean the Research Term and a period of [**]
thereafter, provided that in no event shall the Option Term extend beyond the
date that is [**] after the Effective Date without the consent of Hybridon,
which consent shall not be unreasonably withheld.

      1.50. "PATENTS" shall mean all existing patents and patent applications
and all patent applications hereafter filed, including any continuation,
continuation-in-part, divisional, provisional or any substitute applications,
any patent issued with respect to any such patent applications, any reissue,
reexamination, renewal or extension (including any supplementary protection
certificate) of any such patent, and any confirmation patent or registration
patent or patent of addition based on any such patent, and all foreign
counterparts of any of the foregoing.

      1.51. "PERSON" shall mean any individual, corporation, partnership,
association, joint-stock company, trust, unincorporated organization or
government or political subdivision thereof.

      1.52. "PROOF OF CONCEPT" shall mean the scientific study of the mechanism
of action of an IMO Lead conducted in man, which supports Novartis'
decision-making about the value of the IMO Lead as a development candidate.

      1.53. "POC PHASE RESEARCH" shall mean research related to the technical
development of IMO Leads leading to human clinical trials, as well as all human
clinical trials through the end of Proof of Concept clinical trials.

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      1.54. "PRODUCT" shall mean a pharmaceutical product including, conjugated
to, or comprised of an IMO Lead with or without other active ingredients in
finished dosage form, ready for administration to the ultimate consumer, and any
Improvements thereto.

      1.55. "PROVIDING PARTY" shall have the meaning set forth in Section 5.1
hereof.

      1.56. "RECEIVING PARTY" shall have the meaning set forth in Section 5.1
hereof.

      1.57. "RENEWAL NOTICE" shall have the meaning set forth in Section 2.1.2
hereof.

      1.58. "RENEWAL PERIOD" shall have the meaning set forth in Section 2.1.2
hereof.

      1.59. "RESEARCH COSTS" shall mean all research costs (internal or
external, including manufacturing costs) incurred by a Party in performing such
Party's obligations under the Research Program in accordance with the Research
Plan, and, in the case of Hybridon, any such costs not contemplated by the
Research Plan for which Hybridon has obtained prior written approval from
Novartis which are evidenced by a written invoice, contract or other document
provided by a Third Party.

      1.60. "RESEARCH FIELD OF USE" shall mean the prophylaxis, palliation,
diagnosis and treatment of human diseases by pharmaceutical products via any
route of administration.

      1.61. "RESEARCH PLAN" shall have the meaning set forth in Section 2.2.1
hereof.

      1.62. "RESEARCH PROGRAM" shall mean all research activities undertaken
under this Agreement associated with the identification, generation,
modification and/or characterization of IMO Candidates and IMO Leads, including,
without limitation, all CSP Phase Research activities, which shall be performed
in connection with the Research Plan.

      1.63. "RESEARCH TERM" shall have the meaning set forth in Section 2.1.1
hereof.

      1.64. "SUBSTITUTE IMO LEAD" shall mean any IMO Candidate chosen by
Novartis as a substitute for an abandoned IMO Lead. Substitute IMO Leads, if
any, shall be considered IMO Leads for all purposes hereof, and all references
to the term "IMO Lead" shall be deemed to include any and all Substitute IMO
Leads. Abandoned IMO Leads shall, upon abandonment, cease to be IMO Leads but
shall remain IMO Candidates.

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      1.65. "TERM" shall have the meaning set forth in Section 9.1 hereof.

      1.66. "TERRITORY" shall mean the entire world.

      1.67. "TEST SAMPLE" shall have the meaning set forth in Section 2.3.1
hereof, but shall exclude the following immunomodulatory oligonucleotides: [**].

      1.68. "THIRD PARTY" shall mean any Person that is not a Party or an
Affiliate of either Party.

                                   ARTICLE II

                                RESEARCH PROGRAM

      2.1. RESEARCH TERM.

                  2.1.1. Initial Research Term. The initial term of the Research
Program will commence on the Effective Date and continue for a period of two (2)
years, unless earlier terminated in accordance with the provisions hereof (the
"Initial Research Term"). The Initial Research Term, together with any and all
extensions under Section 2.1.2, 2.1.3, or 2.1.4, shall be referred to as the
"Research Term."

                  2.1.2. Extension of Research Term. Unless earlier terminated
in accordance with the provisions hereof, the Research Term may be extended
beyond the Initial Research Term for [**] (the "Renewal Period"), in the sole
discretion of Novartis, upon the provision of written notice to Hybridon not
later than [**] prior to the end of the Initial Research Term ("Renewal
Notice").

                  2.1.3. Extension in Event of PoC Phase Research Clinical Trial
or Volunteer Study Clinical Trial. In the event that Novartis extends the
Research Term in accordance with Section 2.1.2 and an active clinical trial that
is part of PoC Phase Research is ongoing at the end of the Renewal Period, the
term of the Research Program will automatically extend until completion of (a)
such clinical trial that is part of such PoC Phase Research, if such clinical
trial is designed to establish Proof of Concept, or (b) in the case of such
clinical trial that is part of PoC Phase Research but that is not designed to
establish Proof of Concept, the related clinical trial that is part of PoC Phase
Research and that is designed to establish Proof of Concept (the

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"Extended Renewal Period"); provided that in no event shall the Extended Renewal
Period or the Option Term extend beyond the date that is [**] after the
Effective Date without the consent of Hybridon, which consent shall not be
unreasonably withheld.

                  2.1.4. Continuation of Research Program Upon Option Exercise.
In the event that Novartis exercises the Commercialization Option, this
Agreement shall, subject to the following sentence or as otherwise specified
herein, continue in accordance with its terms (including, without limitation,
the provisions of Section 2.3.3(b) hereof) and shall remain in effect until the
date that is [**] after the Effective Date or such longer period to which
Hybridon consents (which consent shall not be unreasonably withheld), unless
earlier terminated in accordance with the provisions hereof. Beginning upon the
Effective Date of the License Agreement, the PoC Phase Research to be performed
pursuant to Section 2.3.3(a) hereof shall be performed under, and governed by
the terms of, the License Agreement.

      2.2. RESEARCH PLAN.

                  2.2.1. Research Plan. Attached as Schedule 2.2.1 hereto is an
initial work plan identifying: (a) the Acceptance Criteria; (b) the
responsibilities of each Party with respect to research to be conducted prior to
the CSP Phase Research; and (c) the appropriate resources of each Party to be
committed with respect to research to be conducted prior to the CSP Phase
Research. No later than [**] after the Effective Date, Novartis, in consultation
with Hybridon, will prepare an overall research plan for the CSP Phase Research
to be conducted pursuant to the Research Program identifying: (i) the Acceptance
Criteria; (ii) the responsibilities of each Party with respect to the CSP Phase
Research to be conducted; (iii) the appropriate resources of each Party to be
committed with respect to the CSP Phase Research; and (iv) the research
activities, studies, developmental milestones, performance criteria, and
timeframes for work to be completed by each Party with respect to the CSP Phase
Research), which the Parties will submit to the JRC for final approval at the
first meeting of the JRC (such research plan, as approved by the JRC and as
amended from time-to-time, the "Research Plan," except that any changes to the
Acceptance Criteria must be made upon the mutual written consent of the Parties,
such consent not to be unreasonably withheld). The Research Plan and any
amendments thereto shall be included on Schedule 2.2.1 hereto.

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                  2.2.2. Plan Review. The Research Plan will be reviewed and
approved by the JRC shortly after the Effective Date. The JRC may modify the
Research Plan as appropriate; provided, that no modified Research Plan shall
impose substantial resource and/or financial obligations on Hybridon in addition
to those obligations set forth in the initial Research Plan without Hybridon's
consent. Any disagreements between the Parties with respect to modification of
the Research Plan will, subject to the proviso in the immediately preceding
sentence, be resolved in accordance with Section 2.5 of this Agreement.

      2.3. RESEARCH PROGRAM.

               2.3.1. Commencement.

            (a)   Within [**] of the Effective Date, Hybridon, at its own cost,
                  shall generate and supply to Novartis a sufficient number and
                  quantity of IMOs (each a "Test Sample"), to allow evaluation
                  of such Test Samples by the Parties in various in vitro or in
                  vivo assays. In order to facilitate the goals and purposes of
                  the Research Program, Hybridon shall use commercially
                  reasonable efforts to supply Novartis with Test Samples of
                  those IMOs which, in Hybridon's judgment, have the greatest
                  chance (as compared to other IMOs) of meeting the Acceptance
                  Criteria. Each such Test Sample shall be accompanied by all
                  data generated by Hybridon with respect thereto and shall not
                  be required to be materially in excess of the quantity
                  necessary to complete such assays (currently estimated to be
                  up to approximately five (5) grams of each IMO). Based on the
                  results of its evaluation, Novartis, in its discretion, which
                  is reasonably exercised, shall determine whether the Test
                  Samples meet the Acceptance Criteria. From those Test Samples
                  meeting the Acceptance Criteria, Novartis shall, in its sole
                  discretion, identify up to [**] IMO Candidates to be included
                  within the CSP Phase Research. Hybridon's obligation to
                  provide IMOs pursuant to this Section 2.3.1(a) shall be
                  satisfied once Hybridon supplies, in accordance with this
                  Section 2.3.1, Test Samples for IMOs, [**] of which Novartis
                  has determined, in its discretion, which is reasonably
                  exercised, meet the Acceptance Criteria; provided that, if,
                  during the Research Term Novartis

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                  requests that Hybridon generate or supply modified or
                  additional IMOs in response to scientific results that
                  Novartis generates during the Research Program, Hybridon shall
                  use commercially reasonable efforts to provide up to [**]
                  additional IMOs, including Test Samples thereof, at Hybridon's
                  expense.

            (b)   The JRC shall direct the conduct of activities under the
                  Research Plan, and Hybridon and Novartis shall collaborate in
                  the conduct of activities under the Research Plan with the
                  Parties having the roles and responsibilities specified in the
                  Research Plan, all as may be deemed appropriate by the JRC.
                  The JRC shall review and coordinate the efforts of the Parties
                  with respect to the Research Plan.

               2.3.2. CSP Phase Research.

            (a)   During the phase of the Research Program culminating in the
                  candidate selection point (the "CSP Phase Research"), the
                  Parties shall evaluate up to [**] IMO Candidates in various in
                  vitro screens and in vivo models such as those described on
                  Schedule 2.3.2 hereof and shall identify IMO Candidates to be
                  included in the PoC Phase Research to be performed under this
                  Agreement (each an "IMO Lead"). Novartis may designate one or
                  more of the IMO Candidates as IMO Leads, but shall not be
                  obligated to include any such IMO Leads in PoC Phase Research
                  to be performed under this Agreement. Notwithstanding the
                  foregoing, in the event Novartis abandons development of an
                  IMO Lead, Novartis may designate a Substitute IMO Lead and
                  advance the Substitute IMO Lead in place of the abandoned IMO
                  Lead.

            (b)   Hybridon shall cooperate with Novartis and any Third Party
                  supplier retained by Novartis, in Novartis' sole discretion,
                  to enable Novartis and/or such Third Party supplier to
                  manufacture and supply IMO Candidates meeting Novartis'
                  specifications for use in the CSP Phase Research. Hybridon
                  shall provide to Novartis and any Third Party supplier all

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                  technical information and Hybridon Know-How necessary or
                  useful to allow Novartis and/or such Third Party supplier to
                  manufacture the IMO Candidates. Hybridon will make available
                  to Novartis those persons that are subject to Hybridon's
                  control with technical information or necessary or useful
                  expertise to assist Novartis and/or the Third Party supplier
                  with the manufacturing process. Hybridon will not charge
                  Novartis for any costs associated with the performance of its
                  obligations under this Section 2.3.2(b), including, without
                  limitation, the time spent by Hybridon personnel in providing
                  assistance to Novartis and/or any Third Party supplier. Other
                  than as set forth in this Section 2.3.2(b), Novartis shall be
                  responsible for the costs of such supply and all other
                  contractual obligations to such Third Party supplier.

            (c)   Novartis management will determine, in its reasonable
                  discretion, whether an IMO meets the Acceptance Criteria. In
                  addition, Novartis management will determine, in its sole
                  discretion, whether to terminate the CSP Phase Research with
                  respect to any particular IMO Candidate, whether the CSP Phase
                  Research has been successfully completed and which, if any, of
                  the IMO Candidates to designate as IMO Leads.

               2.3.3. PoC Phase Research.

            (a)   In the event that Novartis designates one or more IMO Lead(s),
                  Novartis will conduct PoC Phase Research on such IMO Lead(s),
                  including, without limitation, studies regarding [**], with at
                  least the primary clinical endpoints for such PoC Phase
                  Research to be determined by the JRC. Novartis will make all
                  regulatory filings in Europe, the U.S. and/or any other
                  jurisdictions necessary to conduct the PoC Phase Research
                  under this Agreement. Novartis shall, for informational
                  purposes only, periodically share information with the members
                  of the JRC regarding the status of the PoC Phase Research
                  performed under this Agreement and summaries of the results
                  thereof. Novartis management will determine, in its sole
                  discretion, whether to continue or cease the PoC Phase
                  Research being conducted

                                 PAGE 14 OF 54
<PAGE>

                  under this Agreement with respect to any IMO Lead and whether
                  to put forward a Substitute IMO Lead in lieu thereof, in which
                  case Novartis shall notify Hybridon of the same in writing.

            (b)   Hybridon shall cooperate with Novartis and any Third Party
                  supplier retained by Novartis, in Novartis' sole discretion,
                  to enable Novartis and/or such Third Party supplier to
                  manufacture and supply IMO Candidates meeting Novartis'
                  specifications for use in the PoC Phase Research. Hybridon
                  shall provide to Novartis and any Third Party supplier all
                  technical information and Hybridon Know-How necessary or
                  useful to allow Novartis and/or such Third Party supplier to
                  manufacture the IMO Candidates. Hybridon will make available
                  to Novartis those persons that are subject to Hybridon's
                  control with technical information or necessary or useful
                  expertise to assist Novartis and/or the Third Party supplier
                  with the manufacturing process. Hybridon will not charge
                  Novartis for any costs associated with the performance of its
                  obligations under this Section 2.3.3(b), including, without
                  limitation, the time spent by Hybridon personnel in providing
                  assistance to Novartis and/or any Third Party supplier. Other
                  than as set forth in this Section 2.3.3(b), Novartis shall be
                  responsible for the costs of such supply and all other
                  contractual obligations to such Third Party supplier.

               2.3.4. Research Diligence. Hybridon shall use commercially
reasonable efforts to fulfill its obligations under the Research Program and
Research Plan. Novartis shall use commercially reasonable efforts, similar to
those used by Novartis or its Affiliates in the research and development of
other products of Novartis or its Affiliates that are of similar commercial
potential and at a similar stage of research or development, to fulfill its
obligations under the Research Plan and the Research Program.

               2.3.5. Submission of Reports. Upon achieving, or failing to
achieve, each scientific or technical milestone specified in the Research Plan,
Hybridon and Novartis will complete and present to the JRC a report containing
detailed summaries of the data related to such milestone. For purposes thereof,
each Party shall provide (or request its Affiliates to

                                 PAGE 15 OF 54
<PAGE>

provide) to the other Party any necessary information (including, without
limitation, Confidential Information) as may be reasonably required to perform
its obligations under this Agreement.

      2.4. JOINT RESEARCH COMMITTEE. Upon execution of this Agreement, Hybridon
and Novartis will establish a joint research committee ("JRC"), which shall
consist of an equal number of executives or scientists as may be designated by
each Party from time to time. The JRC shall initially have six (6) members, with
each Party having the right to appoint three (3) members. Novartis shall have
the right to appoint one of its members as the JRC Committee Chair. The JRC
shall hold its first meeting within [**] of the Effective Date. Thereafter, the
JRC shall meet quarterly, or with such other frequency as may be established by
the JRC (but in no event less often than three (3) times per year), and at such
time and location as may be established by the JRC. The JRC shall have the
following responsibilities:

            (a)   Provide general oversight of, direct the conduct of, and
                  review and coordinate the efforts of the Parties with respect
                  to, the Research Plan, and monitor the progress of the
                  activities carried out pursuant to the Research Plan;

            (b)   Periodically review the overall goals and strategy of the
                  activities to be conducted under the Research Plan;

            (c)   Subject to Section 2.2.2, identify the number of FTEs required
                  for activities to be conducted under the Research Plan and
                  prioritize the allocation of resources dedicated to the
                  Research Plan (including FTEs);

            (d)   Subject to Section 2.2.2, approve and revise, as appropriate,
                  the Research Plan;

            (e)   Revise, as appropriate, performance milestones (other than
                  milestones the achievement of which are the basis for payments
                  to Hybridon under this Agreement or the License Agreement);

            (f)   Review and edit proposed publications related to the Research
                  Plan and/or the Collaboration;

            (g)   Subject to Sections 2.2.1, 2.2.2 and 2.5.2, revise, as
                  appropriate, the

                                 PAGE 16 OF 54
<PAGE>

                  Acceptance Criteria;

            (h)   Resolve any disagreement between the Parties, and discuss and
                  resolve any other relevant issues submitted to it, in
                  accordance with the dispute resolution procedure set forth in
                  Section 2.5 below.

            The JRC shall have the authority to create teams for individual
projects, each of which will meet (via telephone or video conference or in
person) no less frequently than monthly, and which will report to the JRC on its
progress on activities performed with respect to such project. In addition, the
JRC shall also have the authority to create subcommittees as needed.
Notwithstanding the foregoing, the Parties acknowledge that the JRC shall not
have the authority to amend or modify the terms or conditions of this Agreement.
The JRC shall survive until expiration or termination of this Agreement.

      2.5. DECISIONS OF THE JRC; RESOLUTION OF DISPUTES.

               2.5.1. Decisions of the JRC. Each of Hybridon and Novartis shall
have one vote on the JRC. The JRC shall make decisions unanimously where
possible. In the event of a deadlock, Novartis shall have the deciding vote on
all matters except Critical Issues.

               2.5.2. Dispute Resolution. In the event that the JRC is
deadlocked as to any material increase in financial or other resources required
to be expended by Hybridon in connection with the Research Program (a "Critical
Issue"), then the Parties shall attempt to have the issue resolved in accordance
with the dispute resolution mechanism set forth in Section 11.3 hereof.

      2.6. EXCHANGE OF INFORMATION.

               2.6.1. Reports to JRC. Hybridon and Novartis will share
information (including, without limitation, Confidential Information) regarding
the Collaboration and/or activities conducted under the Research Plan with the
members of the JRC no less frequently than quarterly in order to allow such
members to monitor the progress of the Collaboration.

               2.6.2. Restrictions on Use of Know-How. Know-How disclosed by one
Party to the other Party shall be deemed Confidential Information of the
Providing Party subject to the provisions of Article V.

                                 PAGE 17 OF 54
<PAGE>

               2.6.3. Delivery of Know-How. During, and upon conclusion of, the
Research Program, and subject to the provisions of this Section 2.6 and Article
V hereof, Hybridon shall (a) disclose to Novartis all technical information
known to it which constitutes Hybridon Know-How (to the extent licensed under
this Agreement) and Joint Know-How and (b) transfer to Novartis all data and
materials specified in the related Research Plan. Hybridon shall provide all
data both in hard copy form and, if commercially and technically reasonable, in
an electronic form compatible with Novartis' systems; provided that Novartis
shall only reimburse Hybridon's costs of providing data in a form compatible
with its systems so long as Hybridon has provided Novartis with a reasonably
detailed description of such costs and obtained Novartis' prior written approval
to incur such costs. Novartis shall reimburse such pre-approved costs actually
incurred by Hybridon within [**] after receipt by Novartis of Hybridon's Invoice
for the same.

               2.6.4. Background Intellectual Property; Non-Interference.

            (a)   Neither Party shall be entitled to information from the other
                  Party concerning Hybridon Intellectual Property or Novartis
                  Intellectual Property, as applicable, discovered or developed
                  by that Party outside the Research Program; except that
                  Hybridon must disclose to the JRC in a timely manner any and
                  all Hybridon Background Intellectual Property that it uses
                  and/or is relevant to the Research Program, and each Party
                  must disclose to the JRC all Joint Intellectual Property it
                  conceives, discovers or develops under the Research Program.

            (b)   Hybridon will not assert its rights in any Acquisition
                  Intellectual Property, Hybridon Intellectual Property,
                  Hybridon Background Intellectual Property or Joint
                  Intellectual Property, as applicable, and will use best
                  efforts to prevent its licensees, if any, from asserting
                  similar rights licensed by Hybridon to such licensees to block
                  or impede Novartis or its Affiliates or their assignees,
                  licensees or sublicensees from exercising the rights licensed
                  to Novartis herein or in the License Agreement.

                                 PAGE 18 OF 54
<PAGE>

      2.7. PRIMARY DATA ACCESS.

               2.7.1. Recordkeeping. Hybridon and Novartis shall each maintain
records in sufficient detail, and will document in a manner appropriate for
purposes of supporting the filing of potential patent applications, all work
done and results achieved in the performance of the Research Program and the
Research Plan (including, without limitation, all data necessary in the form
required under any applicable governmental regulations).

               2.7.2. Technical Reports. Subject to Article V hereof: (a)
Hybridon shall grant to Novartis access, at reasonable intervals and upon
reasonable notice, to all data (including, without limitation, all primary data
and data contained in laboratory notebooks) generated in the course of
performing its obligations under the Research Program; (b) Novartis shall have
the right, at reasonable intervals, to make copies of such data to use and
transfer as permitted hereunder; and (c) Novartis shall have the right to use
and transfer such data in accordance with the licenses granted hereunder.
Notwithstanding anything to the contrary in this Agreement or the License
Agreement, except in connection with the exercise by Novartis of an Additional
Indication Option under the License Agreement, Novartis shall not disclose to
Hybridon or to the JRC any data relating to indications, uses of IMOs or
improvements to IMOs outside the Commercial Field of Use.

                                   ARTICLE III

                                    PAYMENTS

      3.1. STAFFING AND RESEARCH SUPPORT PAYMENTS.

               3.1.1. Reimbursement of Research Costs. Except for Research Costs
payable by Hybridon pursuant to the first sentence of Sections 2.3.1(a),
2.3.2(b), and 2.3.3(b), Novartis shall be responsible for all Research Costs and
costs incurred in connection with Section 2.6.3 and shall reimburse Hybridon for
actual Research Costs incurred by Hybridon within [**] after receipt by Novartis
of Hybridon's Invoice for the same.

               3.1.2. FTE Allocation. The JRC shall determine the appropriate
number of FTEs to be assigned to perform activities under the Research Plan and
the manner in which such FTEs shall be allocated in order to best achieve the
goals set forth in the Research Plan. The

                                 PAGE 19 OF 54
<PAGE>

Parties agree that such number of FTEs shall not exceed [**] per year. Novartis
shall fund such FTE support as the JRC determines for the period of time
beginning on the date on which the JRC approves the Research Plan and ending on
the date on which the activities under the Research Plan are completed (or upon
the expiration or termination of this Agreement, if earlier). Novartis will
remit to Hybridon an amount equal to the FTE Rate times the number of FTEs
actually carrying out the activities assigned to Hybridon, prorated for the time
period that the work was actually being performed under the Research Plan as set
forth in Section 1.23.

               3.1.3. FTE Payments. Novartis shall make all payments for FTE
support under the Research Plan to Hybridon quarterly in arrears within [**]
after receipt by Novartis of Hybridon's Invoice for the same. All payments shall
be made without deduction for withholding or other similar taxes, in U.S.
dollars to the credit of such bank account as may be designated by Hybridon in
writing to Novartis. Any payments which fall due on a date which is a legal
holiday in Bermuda, Switzerland or the United States may be made on the next
following day which is not a legal holiday in the Bermuda, Switzerland or the
United States.

               3.1.4. Records.

            (a)   Hybridon shall keep accurate records and books of accounts
                  containing all data reasonably required for the calculation
                  and verification of Research Costs and FTEs employed by, or
                  equivalents supplied by, Hybridon for activities performed in
                  accordance with the Research Plan. At Novartis' request,
                  Hybridon shall make those records available during reasonable
                  working hours for review by a recognized independent
                  accounting firm acceptable to both Parties for the sole
                  purpose of verifying the accuracy of those records in the
                  calculation of Research Costs and FTEs. Novartis shall use
                  commercially reasonable efforts to cause the accounting firm
                  to retain all such information in confidence. Subject to
                  Section 3.1.4(b) hereof, such reviews shall be at Novartis'
                  expense and shall be conducted no more frequently than once
                  per year. Notwithstanding the foregoing, in the event Hybridon
                  is required or elects to restate its accounts, Novartis shall
                  be entitled to conduct an additional review pursuant to this
                  Section 3.1.4.

                                 PAGE 20 OF 54
<PAGE>

            (b)   If the audit shows any underpayment or overcharging by any
                  Party, that underpayment or overcharging shall be reported to
                  the JRC and the underpaying or overcharging Party shall remit
                  such underpayment or reimburse such overcompensation (together
                  with interest at the rate of one percent (1%) per annum) to
                  the underpaid or overcharged Party within thirty (30) calendar
                  days of receiving the audit report. Further, if the audit for
                  an annual period shows an underpayment or an overcharge by any
                  Party for such period in excess of five percent (5%) of the
                  amounts properly determined, the underpaying or overcharging
                  Party, as the case may be, shall reimburse the applicable
                  underpaid or overcharged Party, for its respective audit fees
                  and reasonable out-of-pocket expenses in connection with said
                  audit, which reimbursement shall be made within [**] of
                  receiving appropriate invoices and other support for such
                  audit-related costs.

      3.2. UPFRONT PAYMENT. A one-time, non-creditable, non-refundable upfront
payment of Four Million U.S. Dollars (U.S. $4,000,000) for access by Novartis to
the Hybridon Intellectual Property related to the IMOs for the Research Term and
Hybridon's participation in the Research Program shall become payable upon
execution hereof. An Invoice for such payment is attached hereto as Schedule 3.2
and shall be deemed delivered pursuant to Section 11.13 hereof upon the
Effective Date and Novartis shall make such upfront payment within [**] days
after the Effective Date.

      3.3. RESEARCH PROGRAM PAYMENTS. In addition to the payments pursuant to
Sections 3.1 and 3.2 above, Novartis shall make the following payments to
Hybridon in connection with the Research Program. Each payment shall be made
within [**] days of Novartis' receipt of the related Hybridon Invoice.

               3.3.1. Renewal Period Payment. In the event that Novartis extends
the Initial Research Term pursuant to Section 2.1.2 hereof, Novartis shall make
a one-time, non-creditable, non-refundable payment of [**] U.S. Dollars (U.S.
$[**]) to Hybridon. Hybridon shall submit its Invoice for the same to Novartis
once Hybridon has received the Novartis Renewal Notice. No payment obligation
shall accrue in respect of an extension of the Renewal Period pursuant to
Section 2.1.3 hereof.

                                 PAGE 21 OF 54
<PAGE>

               3.3.2. IMO Lead Payments. Within [**] of a FPFV with respect to
an IMO Lead, Novartis shall notify Hybridon in writing as to the occurrence of
such FPFV (a "FPFV Notice"). Hybridon shall submit its Invoice for the same to
Novartis once Hybridon has received the FPFV Notice. Upon receipt of such
Invoice, Novartis shall make a one-time, non-creditable (except as otherwise set
forth below in this Section 3.3.2), non-refundable payment of [**] U.S. Dollars
(U.S. $[**]) to Hybridon. Such FPFV Notice and payment shall be required only in
connection with the first [**] IMO Leads and such payment shall not be payable
in connection with a Substitute IMO Lead if such payment was previously made for
the initial IMO Lead replaced by the Substitute IMO Lead. In the event any IMO
Lead is replaced with a Substitute IMO Lead, the Substitute IMO Lead shall not
be considered a separate IMO Lead for the purposes of this Agreement, and all
milestone payments previously paid with respect to such initial IMO Lead shall
be fully creditable as payment for the related Substitute IMO Lead.

                                   ARTICLE IV

                LICENSE, DEVELOPMENT AND COMMERCIALIZATION RIGHTS

      4.1. RESEARCH LICENSE.

               4.1.1. Hybridon Intellectual Property. Subject to the terms of
this Agreement and during the Term, Hybridon hereby grants to Novartis and its
Affiliates an exclusive (subject to Hybridon's retention of rights sufficient to
perform its obligations hereunder and to the rights Hybridon has granted to
EpiGenesis pursuant to the EpiGenesis Agreement), non-transferable (except in
accordance with Section 11.9), and sublicensable license in the Territory under
the Hybridon Intellectual Property and Hybridon's interest in the Joint
Intellectual Property to research and develop IMO Candidates in the Research
Field of Use.

               4.1.2. Hybridon Background Intellectual Property. Subject to the
terms of this Agreement and during the Term, Hybridon hereby grants to Novartis
and its Affiliates a non-exclusive, non-transferable (except in accordance with
Section 11.9), and sublicensable license in the Territory under the Hybridon
Background Intellectual Property to research and develop IMO Candidates in the
Research Field of Use (together with the license granted in Section 4.1.1 above,
the "Novartis Research License").

                                 PAGE 22 OF 54
<PAGE>

               4.1.3. Limitations. Notwithstanding the foregoing, nothing herein
shall give Novartis or its Affiliates the right to, and Novartis shall not (and
shall not permit its Affiliates to) during the term of this Agreement: (i)
Chemically Modify any IMO Candidate or use the Hybridon Intellectual Property to
create any immunomodulatory oligonucleotide that is the same or substantially
structurally equivalent to any IMO Candidate or that is covered by any Valid
Claim in the Hybridon Patents; (ii) conduct any clinical trial designed to
support an indication outside the Commercial Field of Use without Hybridon's
consent; or (iii) prior to Novartis' exercise of the Commercialization Option,
initiate any clinical trial with respect to an IMO Candidate beyond the clinical
trial(s) required to establish Proof of Concept (i.e., initiate any phase II(b)
clinical trial, any phase III clinical trial or any pivotal clinical trial, as
those terms are commonly understood in the pharmaceutical industry).

               4.1.4. Sublicensing. Any sublicense granted by Novartis pursuant
to this Agreement must be granted pursuant to a written agreement that subjects
the sublicensee to not less than the relevant restrictions, limitations and
obligations in this Agreement. Novartis shall remain primarily responsible for
all of its obligations under this Agreement and shall take prompt action to
enforce its rights against its sublicensees should any such sublicensee breach
its obligation to comply with the restrictions, limitations or obligations set
forth in this Agreement. Novartis shall designate Hybridon as a third party
beneficiary if Hybridon is damaged as a result of any breach by a sublicensee of
any relevant restriction, limitation, or obligation pertaining to this
Agreement.

      4.2. COMMERCIALIZATION OPTION.

               4.2.1. Commercialization Option. Novartis has the exclusive right
(the "Commercialization Option") during the Option Term to license exclusively
any and all IMO Candidates, including, without limitation, IMO Leads, for
commercialization of Products in the Commercial Field of Use, under the terms
and conditions set forth in the License Agreement.

               4.2.2. Exercise of Option. Novartis may exercise its
Commercialization Option by delivering to Hybridon written notice of exercise (a
"Commercialization Exercise Notice"). The license grants contemplated by the
License Agreement shall become effective upon the Effective Date of the License
Agreement (as set forth in Section 2.1 thereof). Novartis may exercise the
Commercialization Option during the Option Term. If Novartis does not

                                 PAGE 23 OF 54
<PAGE>

exercise the Commercialization Option during the Option Term, the
Commercialization Option shall expire and have no further force or effect.
Exercise of the Commercialization Option with respect to one IMO Lead licensed
hereunder shall constitute exercise of the Commercialization Option with respect
to any and all IMO Candidates and IMO Leads licensed hereunder.

      4.3. EXCLUSIVITY. During the period beginning on the Effective Date and
throughout the Option Term, and during the entire term of the License Agreement
if Novartis exercises the Commercialization Option: (i) Hybridon shall neither
grant to any Third Party rights to any immunomodulatory oligonucleotide other
than Excluded Antisense IP in the Commercial Field of Use, nor shall Hybridon
develop or commercialize, directly or indirectly, any immunomodulatory
oligonucleotide other than Excluded Antisense IP in the Commercial Field of Use;
and (ii) Hybridon shall neither grant to any Third Party rights to any Test
Sample, IMO Candidate or IMO Lead for any indication, nor shall Hybridon develop
or commercialize, directly or indirectly, any such IMO Candidate or IMO Lead for
any indication. Notwithstanding the foregoing, in the event that Hybridon
provides Novartis with more than [**] Test Samples, the provisions of this
Section 4.3 shall cease to apply upon expiration of the Research Term with
respect to those Test Samples Novartis has determined not to include in the CSP
Phase Research.

                                    ARTICLE V

                                 CONFIDENTIALITY

      5.1. UNDERTAKING. Each Party shall keep confidential, and, other than as
provided herein, shall not use or disclose, directly or indirectly, any trade
secrets, confidential or proprietary information, or any other knowledge,
information, documents or materials, owned, developed or possessed by the other
Party (the "Providing Party"), whether in tangible or intangible form, the
confidentiality of which such other Party takes reasonable measures to protect
(collectively, "Confidential Information"). The Parties hereby agree that, for
the purposes of this Agreement, discussion between the Parties regarding
potential IMO Candidates and IMO Leads will be deemed to be the confidential
information of Novartis.

            (a)   A Party receiving Confidential Information (the "Receiving
                  Party") shall use commercially reasonable efforts not less
                  than those efforts such

                                 PAGE 24 OF 54
<PAGE>

                  Receiving Party uses to protect its own proprietary
                  information to prevent the unauthorized use and disclosure of
                  such information of the Providing Party, and to prevent
                  unauthorized persons or entities from obtaining or using such
                  information.

            (b)   The Receiving Party further agrees to refrain from directly or
                  indirectly taking any action which would constitute or
                  facilitate the unauthorized use or disclosure of Confidential
                  Information. The Receiving Party may disclose Confidential
                  Information to its Affiliates, officers, employees and agents,
                  to authorized licensees and sublicensees, and to
                  subcontractors in connection with the identification,
                  generation, development and manufacture of IMOs, as
                  applicable, to the extent necessary to enable such parties to
                  perform their obligations hereunder or under the applicable
                  license, sublicense or subcontract, as the case may be;
                  provided, however, that such Affiliates, officers, employees,
                  agents, licensees, sublicensees and subcontractors have
                  entered into confidentiality agreements for secrecy and
                  non-use of such Confidential Information offering no less than
                  the protection afforded hereby which by their terms shall be
                  enforceable by injunctive relief at the instance of the
                  Providing Party.

            (c)   The Receiving Party shall be liable for any unauthorized use
                  and disclosure of such information by its Affiliates,
                  officers, employees and agents and any such sublicensees and
                  subcontractors.

      5.2. EXCEPTIONS.

               5.2.1. Non-Confidential Information. Notwithstanding the
foregoing, the provisions of Section 5.1 hereof shall not apply to Confidential
Information that the Receiving Party can establish by clear and convincing
evidence:

            (a)   have entered the public domain without such Receiving Party's
                  breach of any obligation owed to the Providing Party;

            (b)   are or have become known to the Receiving Party from a source
                  other than the Providing Party, other than by breach of an
                  obligation of confidentiality

                                 PAGE 25 OF 54
<PAGE>

                  owed to the Providing Party; or

            (c)   are independently developed by the Receiving Party without
                  reference to or reliance upon knowledge, information,
                  documents or materials of the Providing Party and without
                  breach of this Agreement.

               5.2.2. Other Exceptions. In addition, a Receiving Party may,
notwithstanding the obligations of Section 5.1, disclose Confidential
Information:

            (a)   that the Receiving Party can establish by clear and convincing
                  evidence is permitted to be disclosed by the prior written
                  consent of the Providing Party;

            (b)   that the Receiving Party can establish by clear and convincing
                  evidence is required to be disclosed by the Receiving Party to
                  defend litigation or to comply with applicable laws or
                  regulations (including without limitation disclosure
                  obligations under applicable securities laws or the
                  regulations of any stock exchange or NASDAQ), or in connection
                  with filings with the FDA, the United States Patent and
                  Trademark Office or other similar governmental agencies,
                  provided that the Receiving Party provides prior written
                  notice of such disclosure to the Providing Party and takes
                  reasonable and lawful actions to avoid or minimize the degree
                  of such disclosure; or

            (c)   concerning the existence and terms of this Agreement and the
                  status of transactions described herein, under obligations of
                  confidentiality, to the Receiving Party's existing and
                  potential advisors, investors that are bona fide venture
                  capital or institutional investors that make such investments
                  for the potential financial return and not for strategic
                  purposes (so long as such investor does not have more than
                  $1 billion in world-wide pharmaceutical revenue in the most
                  recently completed calendar year) and any Person considering
                  to acquire Hybridon or a controlling interest in Hybridon (a
                  "Potential Acquirer"). Notwithstanding the foregoing, Hybridon
                  shall not make any such disclosure to any Potential Acquirer
                  (i) until discussions

                                 PAGE 26 OF 54
<PAGE>

                  with such Potential Acquirer progress to a stage at which the
                  Potential Acquirer is engaged in comprehensive due diligence
                  of Hybridon's business and Hybridon has a good faith belief
                  that the consummation of the proposed acquisition has become
                  reasonably likely to occur and (ii) unless the Potential
                  Acquirer has entered into a confidentiality agreement at least
                  as strict as the provisions of this Section 5.2.2(c),
                  designating Novartis as a third party beneficiary and
                  prohibiting the Potential Acquirer from disclosing or using
                  for its own purposes (other than evaluation of the proposed
                  transaction with Hybridon) any such information. Hybridon
                  shall notify Novartis in writing prior to any disclosure
                  pursuant to this Section 5.2.2(c), but shall not be required
                  to disclose the identity of any Potential Acquirer until after
                  consummation or abandonment of the transaction, at which time
                  Hybridon shall provide Novartis with a copy of the
                  confidentiality agreement executed by such Potential Acquirer.

      5.3. PUBLICITY. The Parties will agree upon the timing and content of any
initial press release or other public communications relating to this Agreement
and the transactions contemplated herein.

            (a)   Except as set forth in Section 5.3(b) or to the extent already
                  disclosed in that initial press release or other public
                  communication, no public announcement concerning the existence
                  or the terms of this Agreement or the transactions described
                  herein shall be made, either directly or indirectly, by
                  Hybridon or Novartis, except as may be legally required by
                  applicable laws, regulations, or judicial order, without first
                  obtaining the approval of the other Party and agreement upon
                  the nature, text, and timing of such announcement.

            (b)   Subject to this Article V, a Party may issue press releases or
                  make public communications or otherwise make disclosures that
                  such Party determines to be necessary to comply with
                  applicable law (including disclosure requirements of the U.S.
                  Securities and Exchange Commission, NASDAQ or any stock
                  exchange on which securities issued by such Party are traded);

                                 PAGE 27 OF 54
<PAGE>

                  provided that such Party shall provide the other Party with a
                  copy of the proposed text of such press releases, public
                  communications or disclosure in advance of the scheduled
                  release or publication thereof to afford such other Party a
                  reasonable opportunity to review and comment upon the proposed
                  text.

            (c)   The Party desiring to make any such public announcement shall
                  provide the other Party with a written copy of the proposed
                  announcement in sufficient time (no less than [**] or such
                  shorter period as may be required to enable a Party to comply
                  with applicable law) prior to public release to allow such
                  other Party to comment upon such announcement, prior to public
                  release.

      5.4. SURVIVAL. The provisions of this Article V shall survive for [**]
years after the expiration or termination of this Agreement.

                                   ARTICLE VI

                                   PUBLICATION

      6.1. PUBLICATION. Hybridon and its Affiliates agree not to publish or
publicly present any results, data, or scientific findings with respect to the
Research Program (except in connection with filings with the FDA, the United
States Patent and Trademark Office or other similar governmental entities in
other countries or regions) without the prior written consent of Novartis.
Publication shall be presumed to be impermissible until Novartis shall have
determined, in its sole judgment, that the intellectual property rights in such
information first shall have been adequately protected, whether by foreign
filing of Patents or otherwise. In publications, each Party hereto shall
acknowledge appropriately the contribution of the other Party.

      6.2. SURVIVAL. The provisions of this Article VI shall survive until the
earlier of (i) expiration of the Option Term or (ii) the Effective Date (as
defined in the License Agreement) of the License Agreement, at which time the
terms of the License Agreement shall govern.

                                 PAGE 28 OF 54
<PAGE>

                                   ARTICLE VII

                                 INDEMNIFICATION

      7.1. INDEMNIFICATION BY HYBRIDON. Hybridon will indemnify, defend, and
hold Novartis and its Affiliates, their respective employees, shareholders,
officers, directors, and agents and consultants, and the successors, heirs and
assigns of each of them, harmless against any loss, damages, action, suit,
claim, demand, liability, expense, bodily injury, death or property damage
including reasonable attorney fees (a "Loss") that may arise from Third Party
claims brought, instituted or arising against such persons to the extent such
Loss is based on or arises out of the breach by Hybridon of any of its
covenants, representations or warranties set forth in this Agreement, but
excluding any such Loss that is caused by the negligent, willful or reckless
acts or omissions of Novartis.

      7.2. INDEMNIFICATION BY NOVARTIS. Novartis will indemnify, defend, and
hold Hybridon, and its Affiliates, and their respective employees, shareholders,
officers, directors, agents and consultants and the successors, heirs, and
assigns of each of them, harmless against any Loss that may arise from Third
Party claims brought, instituted or arising against such persons to the extent
such Loss is based on or arises out of (a) the breach by Novartis of any of its
covenants, representations or warranties set forth in this Agreement, but
excluding any such Loss that is caused by the negligent or reckless acts or
omissions of Hybridon or (b) the development, manufacture, use, storage or
handling of an IMO Candidate or IMO Lead by Novartis or its Affiliates or their
representatives, agents, licensees, sublicensees or subcontractors under this
Agreement, or any actual or alleged violation of law resulting therefrom,
including without limitation any death or bodily injury caused or allegedly
caused by the use of the IMO Candidate or IMO Lead, but excluding any such Loss
that is caused by the negligent, willful or reckless acts or omissions of
Hybridon.

      7.3. CLAIMS PROCEDURES. Each Person entitled to be indemnified by the
other Party (an "Indemnified Person") pursuant to Sections 7.1 or 7.2 hereof
shall give notice to the other Party (an "Indemnifying Party") promptly after
such Indemnified Person has actual knowledge of any threatened or asserted claim
as to which indemnity may be sought, and shall permit the Indemnifying Party to
assume the sole control of the defense of any such claim or any litigation
resulting therefrom; provided, however:

                                 PAGE 29 OF 54
<PAGE>

            (a)   that counsel for the Indemnifying Party, who shall conduct the
                  defense of such claim or any litigation resulting therefrom,
                  shall be approved by the Indemnified Person (whose approval
                  shall not unreasonably be withheld) and the Indemnified Person
                  may participate in such defense at such Party's expense
                  (unless: (i) the employment of counsel by such Indemnified
                  Person has been authorized by the Indemnifying Party; or (ii)
                  the Indemnified Person shall have reasonably concluded that
                  there may be a conflict of interest between the Indemnifying
                  Party and the Indemnified Person in the defense of such
                  action, in each of which cases the Indemnifying Party shall
                  pay the reasonable fees and expenses of one law firm serving
                  as counsel for all Indemnified Persons with respect to such
                  action, which law firm shall be subject to approval, not to be
                  unreasonably withheld, by the Indemnifying Party);

            (b)   the failure of any Indemnified Person to give notice as
                  provided herein shall not relieve the Indemnifying Party of
                  its obligations under this Agreement to the extent that the
                  failure to give notice did not result in harm to the
                  Indemnifying Party or materially compromise the defense of
                  such claim;

            (c)   no Indemnifying Party, in the defense of any such claim or
                  litigation, shall consent to entry of any judgment or enter
                  into any settlement, except with the approval of each
                  Indemnified Person (which approval shall not be unreasonably
                  withheld), except a settlement which imposes only a monetary
                  obligation on the Indemnifying Party and which includes as an
                  unconditional term thereof the giving of a release from all
                  liability in respect to such claim or litigation by the
                  claimant or plaintiff to the Indemnified Person;

            (d)   each Indemnified Person shall furnish such information or
                  reasonable assistance regarding itself or the claim in
                  question as an Indemnifying Party may reasonably request in
                  writing and shall be reasonably required in connection with
                  the defense of such claim and litigation resulting therefrom;
                  and

                                 PAGE 30 OF 54
<PAGE>

            (e)   no Indemnified Person shall settle or agree to a judgment with
                  respect to such claim or litigation without the consent of the
                  Indemnifying Party (which consent shall not be unreasonably
                  withheld).

      7.4. COMPLIANCE. The Parties shall comply fully with all applicable laws
and regulations in connection with their respective activities under this
Agreement, including but not limited to applicable rules concerning good
manufacturing practices according to the current EC / Pharmaceutical Inspection
Convention GMP guidelines, the U.S. Code of Federal Regulations, the laws and
regulations of the European Union and the corresponding applicable national laws
and regulations.

      7.5. SURVIVAL. The provisions of this Article VII shall survive expiration
or termination of this Agreement without limitation.

                                  ARTICLE VIII

                          INTELLECTUAL PROPERTY RIGHTS

      8.1. OWNERSHIP.

               8.1.1. Subject to any licenses explicitly granted under this
Agreement, each Party shall retain its intellectual property rights in all
Know-How and Patents Controlled by it on the Effective Date or developed or
acquired solely by it thereafter. For avoidance of any doubts, Novartis shall
retain ownership of all Novartis Intellectual Property, and Hybridon shall
retain ownership of all Hybridon Intellectual Property and Hybridon Background
Intellectual Property.

               8.1.2. During the Term of the Agreement, each of Hybridon and
Novartis will keep the other Party fully informed with respect to any new
intellectual property invented or generated by it or its Affiliates under this
Agreement.

            (a)   All intellectual property (including, without limitation,
                  data, discoveries, technical information, Know-how, Patents,
                  proprietary information, trade secrets and inventions)
                  invented or generated under this Agreement solely by one or
                  more persons obliged to assign their rights to Novartis or its
                  Affiliates during the Term shall be owned by Novartis and
                  shall be deemed

                                 PAGE 31 OF 54
<PAGE>

                  Novartis Patent Rights or Novartis Know-How as applicable;

            (b)   All intellectual property (including, without limitation,
                  data, discoveries, technical information, Know-how, Patents,
                  proprietary information, trade secrets and inventions)
                  invented or generated under this Agreement solely by one or
                  more persons obliged to assign their rights to Hybridon or its
                  Affiliates during the Term shall be owned by Hybridon and
                  shall be deemed Hybridon Patents or Hybridon Know-How, as
                  applicable;

            (c)   All intellectual property (including, without limitation,
                  data, discoveries, technical information, Know-how, Patents,
                  proprietary information, trade secrets and inventions)
                  invented or generated jointly under this Agreement by (i) one
                  or more persons obliged to assign their rights to Novartis or
                  its Affiliates and (ii) one or more persons obliged to assign
                  their rights to Hybridon or its Affiliates during the Term
                  shall be owned jointly by Novartis and Hybridon and shall be
                  Joint Intellectual Property and, subject to Section 4.1.1,
                  each Party shall have the right to use and exploit such Joint
                  Intellectual Property without any duty to account to the other
                  Party with respect to such use and exploitation. Each Party
                  will take all reasonable actions requested by the other Party,
                  including execution of appropriate patent filings and
                  applications for registration, to perfect the requesting
                  Party's ownership interest to the Joint Intellectual Property;
                  and

            (d)   Questions of inventorship under this Section 8.1.2 shall be
                  resolved in accordance with United States patent laws.

      8.2. PREPARATION AND COSTS. Hybridon shall take responsibility and pay for
the preparation, filing, prosecution and maintenance of all Hybridon Patents and
Patents that are part of the Hybridon Background Intellectual Property, and
Novartis shall take responsibility and pay for the preparation, filing,
prosecution and maintenance of all Novartis Patents and Joint Patents; provided
that, with respect to (a) Hybridon Patents and Patents that are part of the
Hybridon Background Intellectual Property that disclose or claim inventions
applicable solely to the IMO Candidates and IMO Leads and (b) Joint Patents that
disclose or claim inventions with

                                 PAGE 32 OF 54
<PAGE>

applicability beyond the IMO Candidates and IMO Leads, the Party having
responsibility for the preparation, filing, prosecution and maintenance of such
Hybridon Patents, Patents that are part of the Hybridon Background Intellectual
Property and Joint Patents shall promptly provide the other Party with copies of
all substantive communications from any patent office and with drafts of all
substantive filings to be made, reasonably in advance of their filing, with any
patent office with respect thereto; shall consider in good faith any comments
thereon provided by the other Party; and shall not unreasonably decline to
incorporate changes to such filing proposed by such other Party. Each Party
shall assist the other in the preparation and prosecution of such Patents and
shall execute all documents reasonably deemed necessary for the filing thereof
and/or for the vesting of title thereto as provided in this Agreement. Each
Party shall provide the JRC (or the other Party if the JRC no longer exists)
with periodic reports listing, by name, Hybridon Patents, Patents that are part
of the Hybridon Background Intellectual Property, Novartis Patents and Joint
Patents arising under the Research Program filed in the United States and other
jurisdictions, along with a general summary of the claims made and the
jurisdictions of filing. In good time, before the deadline for foreign filing of
any patent application filed in the United States, Hybridon will notify Novartis
whether it intends to foreign file such patent application, and if it intends to
do so, in what countries it proposes to foreign file.

      8.3. DISCONTINUATION. The Party initially responsible under Section 8.2
for the preparation, filing, prosecution and maintenance of a particular Patent
for an invention arising under the Research Program shall give at least [**]
advance notice to the other Party of any decision to cease preparation, filing,
prosecution or maintenance of that Patent. Discontinuation may be elected on a
country-by-country basis or for a Patent application or Patent series in total.
In such case, the other Party may elect, at its sole discretion, to continue
preparation, filing, and prosecution or maintenance of the discontinued Patent
at its sole expense.

      8.4. SURVIVAL. The provisions of this Article VIII shall survive
expiration or termination of this Agreement without limitation; provided that
the provisions of Section 8.3 as they relate to Patents that are solely owned by
either Party shall not survive expiration or termination of this Agreement.

                                 PAGE 33 OF 54
<PAGE>

                                   ARTICLE IX

                              TERM AND TERMINATION

      9.1. TERM. The term of this Agreement (the "Term") shall begin on the
Effective Date and expire upon expiration of the Option Term unless earlier
terminated by either Party hereto in accordance with this Agreement.

      9.2. TERMINATION.

               9.2.1. Upon ninety (90) days' written notice to Hybridon,
Novartis may, at its sole discretion, unilaterally terminate the Research
Program and this Agreement without cause.

               9.2.2. In the event that Hybridon shall breach any of its
material obligations under this Agreement or Novartis shall breach its
obligations under Section 3.2 hereof, and such breach shall not have been
remedied or steps initiated to remedy the same to the non-breaching Party's
reasonable satisfaction, within thirty (30) days after such non-breaching Party
sends written notice of such breach to the breaching Party, the non-breaching
Party may, at its sole discretion, unilaterally terminate the Research Program
and this Agreement without prejudice to its rights to seek damages in connection
with such breach.

               9.2.3. If at any time during the term of this Agreement, an Event
of Bankruptcy (as defined below) relating to a Party (the "Bankrupt Party")
occurs, the other Party shall have, in addition to all other legal and equitable
rights and remedies available hereunder, the option to terminate this Agreement
upon thirty (30) calendar days' written notice to the Bankrupt Party. As used
above, the term "Event of Bankruptcy" shall mean, with respect to a Party, (a)
the dissolution, termination of existence or liquidation of the Party; (b) the
institution of a bankruptcy action against the Party by a Third Party or the
appointment of a custodian or receiver with respect to all or substantially all
of the business or assets of the Party, which action, custodian or receiver is
not terminated or dismissed within ninety (90) calendar days following
institution or appointment; (c) the institution by the Party of any petition for
relief or similar proceeding or the making by the Party with respect to all or
substantially all of the business or assets of the Party of a composition or any
assignment or trust mortgage for the benefit of

                                 PAGE 34 OF 54
<PAGE>

creditors under any bankruptcy, reorganization, receivership or other similar
law affecting the rights of creditors generally; or (d) the insolvency of the
Party.

      9.3. EFFECT OF TERMINATION.

               9.3.1. In the event of any termination under Section 9.2.1
hereof, Novartis' obligation to perform any further work under the Research
Program shall cease as of the date of the termination notice, and Novartis shall
reimburse Hybridon for all Research Costs actually incurred by Hybridon prior to
the date of termination, regardless of whether such Research Costs become
payable subsequent to such date and shall pay Hybridon all amounts payable in
accordance with Section 3.1.3 for all periods prior to the date of termination,
provided that: (i) following the date of the termination notice, Hybridon shall
not initiate any additional internal activities or contract with any Third Party
for the provision of services or goods that will result in Hybridon incurring
Research Costs and shall use commercially reasonable efforts to minimize all
Research Costs previously incurred (including, without limitation, returning
materials to vendors where possible, winding down ongoing projects, reassigning
personnel to projects outside the Research Program, not initiating new
activities and refraining from hiring additional personnel to perform work on
the Research Program) and (ii) Hybridon shall provide Novartis with appropriate
documentation of such costs.

               9.3.2. Upon any termination of this Agreement by Novartis
pursuant to Section 9.2.1 or Hybridon pursuant to Sections 9.2.2 or 9.2.3: (i)
except with respect to any provision hereof that by its terms survives
termination and any payment obligation of Novartis that has accrued prior to the
date of termination, all rights and obligations of the Parties under this
Agreement shall terminate, (ii) all rights granted by Hybridon to Novartis
pursuant to the Novartis Research License shall revert to Hybridon, (iii) each
Party shall return to the other all Confidential Information of such other
Party, provided, however, that the Parties may each retain a copy of such other
Party's Confidential Information in segregated files solely for archival
purposes, and (iv) if the Commercialization Option has not already been
exercised, the Option Term shall terminate and the Commercialization Option
shall have no further force or effect.

               9.3.3. Upon any termination of this Agreement by Novartis
pursuant to Section 9.2.2 or Section 9.2.3, all rights granted to Novartis
hereunder shall survive (including,

                                 PAGE 35 OF 54
<PAGE>

without limitation, all rights granted by Hybridon to Novartis pursuant to the
Novartis Research License) and the License Agreement shall become effective
immediately, subject to payment by Novartis of the option exercise fee as set
forth in Section 5.1 of the License Agreement. In the event that Novartis fails
to make such payment, the License Agreement shall terminate and shall be of no
further force or effect, effective as of the day immediately following the day
on which such payment is ultimately due. Upon such termination, Novartis'
payment obligations pursuant to Sections 3.1 (with respect to Research Costs and
FTE costs incurred after the date of termination hereof) and 3.3.1 hereof shall
terminate, Novartis' payment obligations (whether arising before or after such
termination of this Agreement) under Section 3.3.2 shall survive for so long as
the License Agreement remains in effect, and all rights granted to Hybridon
hereunder shall terminate. Notwithstanding the foregoing, each Party's rights
and obligations pursuant to Article V with respect to confidentiality, Article
VII with respect to indemnification, and Article VIII with respect to
intellectual property rights shall survive any such termination in accordance
with their terms.

                                    ARTICLE X

                         REPRESENTATIONS AND WARRANTIES

      10.1. REPRESENTATIONS AND WARRANTIES OF HYBRIDON. Hybridon represents and
warrants to Novartis as follows:

               10.1.1. Authorization. This Agreement has been duly executed and
delivered by Hybridon and constitutes the valid and binding obligation of
Hybridon, enforceable against Hybridon in accordance with its terms except as
enforceability may be limited by fraudulent conveyance, insolvency, bankruptcy,
reorganization, moratorium and other laws relating to or affecting creditors'
rights generally and by general equitable principles. The execution, delivery
and performance of this Agreement have been duly authorized by all necessary
action on the part of Hybridon, its officers and directors. No provision of this
Agreement violates any other agreement that Hybridon may have with any other
person or company, and Hybridon acknowledges that Novartis has relied on that
representation in entering into this Agreement.

                                 PAGE 36 OF 54
<PAGE>

               10.1.2. Hybridon Controlled Rights. As of the Effective Date,
Hybridon owns or possesses adequate licenses or other rights to use all Hybridon
Intellectual Property and Hybridon Background Intellectual Property and to grant
the licenses and perform the obligations contemplated herein. The granting of
the Commercialization Option to Novartis hereunder does not violate any right
known to Hybridon of any Third Party.

               10.1.3. Third Party Patents. Except as disclosed in writing
between the Parties to this Agreement or their respective agents, as of the
Effective Date, to the best of Hybridon's knowledge, after reasonable inquiry,
there are no issued patents or pending patent applications that, if issued,
would be infringed by the exercise by Novartis of the rights granted herein or
the development, manufacture, use or sale of the IMO Leads pursuant to this
Agreement.

      10.2. REPRESENTATIONS AND WARRANTIES OF NOVARTIS. Novartis represents and
warrants to Hybridon that this Agreement has been duly executed and delivered by
Novartis and constitutes the valid and binding obligation of Novartis,
enforceable against Novartis in accordance with its terms except as
enforceability may be limited by fraudulent conveyance, insolvency, bankruptcy,
reorganization, moratorium and other laws relating to or affecting creditors'
rights generally and by general equitable principles. The execution, delivery
and performance of this Agreement have been duly authorized by all necessary
action on the part of Novartis, its officers and directors. No provision of this
Agreement violates any other agreement that Novartis may have with any other
person or company, and Novartis acknowledges that Hybridon has relied on that
representation in entering into this Agreement.

      10.3. LIMITATIONS.

               10.3.1. NO OTHER WARRANTIES. EXCEPT AS OTHERWISE EXPRESSLY SET
FORTH IN THIS AGREEMENT, ALL IMPLIED WARRANTIES, INCLUDING IMPLIED WARRANTIES OF
NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
EXCLUDED.

               10.3.2. CONSEQUENTIAL AND PUNITIVE DAMAGES. EXCEPT AS OTHERWISE
EXPRESSLY SET FORTH IN THIS AGREEMENT, NEITHER PARTY WILL BE LIABLE FOR
CONSEQUENTIAL, INCIDENTAL, MULTIPLE, SPECIAL OR PUNITIVE

                                 PAGE 37 OF 54
<PAGE>

DAMAGES OF ANY NATURE ARISING FROM SUCH PARTY'S ACTIVITIES UNDER THIS AGREEMENT;
PROVIDED, HOWEVER, THAT THIS LIMITATION SHALL NOT LIMIT THE INDEMNIFICATION
OBLIGATIONS OF THE PARTIES WITH RESPECT TO THIRD PARTY CLAIMS OR THE OBLIGATIONS
OF EITHER PARTY WITH RESPECT TO A BREACH OF ARTICLE IV OR ARTICLE V.

                                   ARTICLE XI

                            MISCELLANEOUS PROVISIONS

      11.1. GOVERNING LAW AND JURISDICTION. This Agreement shall be governed and
construed in accordance with the internal laws of the State of New York, United
States, and the Parties hereby submit to the exclusive jurisdiction of the
courts of New York.

      11.2. ADVERSE EVENTS. During the term of this Agreement, the Parties shall
keep each other promptly and fully informed and will promptly notify appropriate
authorities in accordance with applicable law, after receipt of information with
respect to any serious adverse event (as defined by the ICH Harmonized
Tripartite Guideline on Clinical Safety Data Management), directly or indirectly
attributable to the use or application of any IMO, and other material safety
information relating to any IMO. Each Party shall be entitled to disclose and
use all such information to regulatory authorities as required under applicable
law or regulation, to licensees, sublicensees and collaborators, under
obligations of confidentiality, for purposes relating to the research,
development and/or commercialization of products incorporating IMOs.

      11.3. DISPUTE RESOLUTION PROCESS FOR CRITICAL ISSUES. In the event of any
Critical Issue which the JRC is unable to resolve, the Parties shall refer the
matter to the President of Hybridon and the Head of the Novartis Respiratory
Disease Area of Novartis Institutes for BioMedical Research, who shall attempt
in good faith and using their best efforts to resolve the Critical Issue within
sixty (60) days of the date of initial referral of the matter from the JRC;
provided that, if such officers are unable to resolve such Critical Issue, the
provisions of Section 2.2.2 shall continue to apply.

                                 PAGE 38 OF 54
<PAGE>

      11.4. WAIVER. No provision of this Agreement may be waived except in
writing by both Parties hereto. No failure or delay by either Party hereto in
exercising any right or remedy hereunder or under applicable law will operate as
a waiver thereof, or a waiver of any right or remedy on any subsequent occasion.

      11.5. FORCE MAJEURE. Neither Party will be in breach hereof by reason of
its delay in the performance of or failure to perform any of its obligations
hereunder, if that delay or failure is caused by strikes, acts of God or the
public enemy, riots, incendiaries, interference by civil or military
authorities, compliance with governmental priorities for materials, or any cause
beyond its control without its fault or negligence.

      11.6. SEVERABILITY. Should one or more provisions of this Agreement be or
become invalid, then the Parties hereto shall attempt in good faith to agree
upon valid provisions in substitution for the invalid provisions, which in their
economic effect and other substance come so close to the invalid provisions that
it can be reasonably assumed that the Parties would have accepted this Agreement
with those new provisions. If the Parties are unable to agree on such valid
provisions, the invalidity of such one or more provisions of this Agreement
shall nevertheless not affect the validity of the Agreement as a whole, unless
the invalid provisions are of such essential importance for this Agreement that
it may be reasonably presumed that the Parties would not have entered into this
Agreement without the invalid provisions.

      11.7. GOVERNMENT ACTS. In the event that any act, regulation, directive,
or law of a country or its government, including its departments, agencies or
courts, should make impossible or prohibit, restrain, modify or limit any
material act or obligation of Novartis or Hybridon under this Agreement, the
Party, if any, not so affected, shall have the right, at its option, to suspend
or terminate this Agreement as to such country, if good faith negotiations
between the Parties to make such modifications therein as may be necessary to
fairly address the impact thereof, are not successful after a reasonable period
of time in producing mutually acceptable modifications to this Agreement.

      11.8. GOVERNMENT APPROVALS. Each Party will use commercially reasonable
efforts to obtain any government approval required to enable this Agreement to
become effective, or to enable any payment hereunder to be made, or any other
obligation hereunder to be observed or performed. Each Party will keep the other
informed of progress in obtaining any such

                                 PAGE 39 OF 54
<PAGE>

government approval, and will cooperate with the other Party in any such
efforts.

      11.9. ASSIGNMENT. This Agreement may not be assigned or otherwise
transferred by either Party without the prior written consent of the other
Party; provided, however, that Novartis may assign this Agreement without the
consent of Hybridon: (i) to any of its Affiliates, if Novartis guarantees to
full performance of such Affiliate's obligations hereunder; or (ii) in
connection with the transfer or sale of all or substantially all of its assets
or business to which this Agreement pertains, or a controlling interest in its
equity, or in the event of its merger or consolidation with another company. Any
purported assignment in contravention of this Section 11.9 shall, at the option
of the non-assigning Party, be null and void and of no effect. No assignment
shall release either Party from responsibility for the performance of any
accrued obligation of such Party hereunder. This Agreement shall be binding upon
and enforceable against the successor to or any permitted assignees of either of
the Parties.

      11.10. AFFILIATES. Each Party may perform its obligations hereunder
personally or through one or more Affiliates, although each Party shall
nonetheless be solely responsible for the performance of its Affiliates. Neither
Party shall permit any of its Affiliates to commit any act (including any act or
omission) which such Party is prohibited hereunder from committing directly.

      11.11. COUNTERPARTS. This Agreement may be executed in counterparts, each
of which shall be deemed to be original and all of which shall constitute one
and the same Agreement.

      11.12. NO AGENCY. Nothing herein contained shall be deemed to create an
agency, joint venture, amalgamation, partnership or similar relationship between
Novartis and Hybridon and/or their respective Affiliates. Notwithstanding any of
the other provisions of this Agreement, neither Party to this Agreement shall at
any time enter into, incur, or hold itself out to Third Parties as having
authority to enter into or incur, on behalf of the other Party, any commitment,
expense, or liability whatsoever, and all contracts, expenses and liabilities in
connection with or relating to the obligations of each Party under this
Agreement shall be made, paid, and undertaken exclusively by such Party on its
own behalf and not as an agent or representative of the other.

      11.13. NOTICE. All communications between the Parties with respect to any
of the

                                 PAGE 40 OF 54
<PAGE>

provisions of this Agreement will be sent to the addresses set out below, or to
such other addresses as may be designated by one Party to the other by notice
pursuant hereto, by (i) personal delivery (which shall be deemed received when
delivered), (ii) reputable international express courier (which shall be deemed
received when delivered), (iii) prepaid, certified mail (which shall be deemed
received by the other party on the seventh (7th) business day following deposit
in the mails), or (iv) facsimile transmission, or other electronic means of
communication (which shall be deemed received when transmitted), with
confirmation in the case of clause (iv) prepaid certified mail, given by the
close of business on or before the next following business day:

                  if to Novartis, at:

                        Novartis International Pharmaceutical Ltd.
                        Hurst Holme
                        12 Trott Road
                        Hamilton, HM 11
                        Bermuda
                        Attention: Emil Bock
                        Fax: [**]
                  with a copy to:

                        Novartis Institutes for BioMedical Research, Inc.
                        400 Technology Square
                        Cambridge, Massachusetts 02139
                        USA
                        Attention: Robert L. Thompson, Vice President and
                          General Counsel
                        Fax: [**]

                  and:

                        Novartis Horsham Research Centre
                        Wimblehurst Road
                        Horsham, West Sussex
                        RH12 5AB
                        United Kingdom
                        Attention: Head of  Novartis Respiratory Disease Area
                        Fax: [**]

      if to Hybridon, at:

                        Hybridon, Inc.
                        345 Vassar Street

                                 PAGE 41 OF 54
<PAGE>

                        Cambridge, Massachusetts 02139
                        USA
                        Attention: President
                        Fax: +(617) 679-5542

                  with a copy to:

                        Wilmer Cutler Pickering Hale and Dorr LLP
                        60 State Street
                        Boston, Massachusetts 02109
                        USA
                        Attention: David E. Redlick, Esq.
                        Fax: +(617) 526-5000

      11.14. HEADINGS. The paragraph headings are for convenience only and will
not be deemed to affect in any way the language of the provisions to which they
refer.

      11.15. AUTHORITY. The undersigned represent that they are authorized to
sign this Agreement on behalf of their respective Parties.

      11.16. ENTIRE AGREEMENT. This Agreement and the License Agreement contain
the entire understanding of the Parties relating to the matters referred to
herein and therein, supersede all prior agreements between the Parties with
respect to such matters (including without limitation the Confidential Term
Sheet dated January 26, 2005, the Material Transfer Agreement dated July 1, 2003
between Hybridon and Novartis Pharmaceuticals UK Limited, as amended prior to
the Effective Date, and the Mutual Confidentiality Agreements dated January 23,
2003 and June 8, 2004 between Hybridon and Novartis Pharmaceuticals UK Limited,
each as amended prior to the Effective Date, but excluding provisions of such
Material Transfer Agreement and Mutual Confidentiality Agreements relating to
restrictions on the use and disclosure of materials and information prior to the
Effective Date (it being understood that any material and information
transferred or disclosed between the Parties prior to the Effective Date
relating to the matters referred to in this Agreement and the License Agreement
will, after the Effective Date, be deemed to have been transferred or disclosed
under, and will be subject to the restrictions on use and disclosure set forth
in, this Agreement and the License Agreement)), and may only be amended by a
written document, duly executed on behalf of the respective Parties.

                            [SIGNATURE PAGE FOLLOWS]

                                 PAGE 42 OF 54
<PAGE>

      IN WITNESS WHEREOF, the Parties have caused this Agreement to be executed
by their duly authorized representatives as of the date first written above.

                                      HYBRIDON, INC.

                                      By: /s/ Sudhir Agrawal
                                          --------------------------------------
                                      Name: Sudhir Agrawal
                                      Title: CEO/President

                                      NOVARTIS INTERNATIONAL PHARMACEUTICAL LTD.

                                      By: /s/ Emil Bock
                                          --------------------------------------
                                      Name: Emil Bock
                                      Title: Member of the Board of Directors

                                      By: /s/ Michael Jones
                                          --------------------------------------
                                      Name: Michael Jones
                                      Title: Member of the Board of Directors

                                 PAGE 43 OF 54
<PAGE>

                                  SCHEDULE 1.28
                                HYBRIDON PATENTS

                                HYBRIDON PATENTS

<TABLE>
<CAPTION>
                                                  STATUS
HYBN #   OTHER CASE #   APPLICATION NO.   TITLE   OF CASE   PATENT #   COUNTRY   FILING DATE   PUBLICATION #
------   ------------   ---------------   -----   -------   --------   -------   -----------   -------------
<S>      <C>            <C>               <C>     <C>       <C>        <C>       <C>           <C>
[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]        [**]      [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]           [**]

[**]         [**]            [**]          [**]    [**]                  [**]       [**]

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</TABLE>

<PAGE>

                                HYBRIDON PATENTS

<TABLE>
<CAPTION>
                                                  STATUS
HYBN #   OTHER CASE #   APPLICATION NO.   TITLE   OF CASE   PATENT #   COUNTRY   FILING DATE   PUBLICATION #
------   ------------   ---------------   -----   -------   --------   -------   -----------   -------------
<S>      <C>            <C>               <C>     <C>       <C>        <C>       <C>           <C>
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</TABLE>

<PAGE>

                                HYBRIDON PATENTS

<TABLE>
<CAPTION>
                                                  STATUS
HYBN #   OTHER CASE #   APPLICATION NO.   TITLE   OF CASE   PATENT #   COUNTRY   FILING DATE   PUBLICATION #
------   ------------   ---------------   -----   -------   --------   -------   -----------   -------------
<S>      <C>            <C>               <C>     <C>       <C>        <C>       <C>           <C>
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</TABLE>

<PAGE>

                                HYBRIDON PATENTS

<TABLE>
<CAPTION>
                                                  STATUS
HYBN #   OTHER CASE #   APPLICATION NO.   TITLE   OF CASE   PATENT #   COUNTRY   FILING DATE   PUBLICATION #
------   ------------   ---------------   -----   -------   --------   -------   -----------   -------------
<S>      <C>            <C>               <C>     <C>       <C>        <C>       <C>           <C>
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</TABLE>

<PAGE>

                                HYBRIDON PATENTS

<TABLE>
<CAPTION>
                                                  STATUS
HYBN #   OTHER CASE #   APPLICATION NO.   TITLE   OF CASE   PATENT #   COUNTRY   FILING DATE   PUBLICATION #
------   ------------   ---------------   -----   -------   --------   -------   -----------   -------------
<S>      <C>            <C>               <C>     <C>       <C>        <C>       <C>           <C>
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</TABLE>

[**]

<PAGE>

HYBRIDON'S LOGO                                                          INVOICE

                                                               INVOICE DATE:
Street                                                         [MONTH][DAY] 200X
Town, Country
Phone and Fax Nr.                                              INVOICE NO.:XXXX

BILL TO:                                       FOR:
Novartis International Pharmaceutical Ltd.     Milestone for   200x
"Hurst Holme", 12 Trott Road                    event Y
Att. Mr. Emil Bock
P.O. Box HM 2899
Hamilton, HM LX
Bermuda

<TABLE>
<CAPTION>
                        DESCRIPTION                               AMOUNT (USD)
--------------------------------------------------------------   ---------------
<S>                                                              <C>
Milestone payment for event Y, according to paragraph XY
of agreement ZZZZ dated ......                                    US$ 000'000.00

Novartis Contract Code

Please specify the event for which the invoice is due, and add
any copies of invoices from third parties in case
reimbursement for third party work is agreed to

PLEASE REMIT BY WIRE TRANSFER WITHIN 60 DAYS TO:

        Receiving Bank - .......
        Swift Code - .......
        ABA Number - .......
        Credit Account - .......
        Beneficiary - .......
                                                                  --------------
                                                         TOTAL        000'000,00
                                                                  ==============
</TABLE>

If you have any questions concerning this invoice, contact ...
or e-mail to .....

VAT -Reg. No. Xxxxxxxxxx (if partner has one)

                BEST REGARDS,

<PAGE>

                                  SCHEDULE 1.40
                                  JOINT PATENTS





          [To be appended upon exercise of the commercialization option.]
<PAGE>

                                 SCHEDULE 2.2.1
                              INITIAL RESEARCH PLAN

             Acceptance Criteria for Hybridon IMO(TM)(TLR9 agonists)
           Criteria to be met to qualify candidate for CSP initiation

<TABLE>
<CAPTION>
            AREA                PARAMETER   ACCEPTANCE CRITERIA (FOR CSP)   RESPONSIBILITY FOR DATA
-----------------------------   ---------   -----------------------------   -----------------------
<S>                             <C>         <C>                             <C>
IN VITRO PHARMACOLOGY             [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
IN VIVO PHARMACOLOGY              [**]                 [**]                          [**]
IN VITRO AND IN VIVO SAFETY       [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
STRUCTURE AND PHYSICOCHEMICAL     [**]                 [**]                          [**]
PROPERTIES
                                  [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
                                  [**]                 [**]                          [**]
</TABLE>

<PAGE>

                                 SCHEDULE 2.3.2
                 EXAMPLES OF POSSIBLE CSP PHASE RESEARCH STUDIES

[**]

<PAGE>

HYBRIDON                            SCHEDULE 3.2
                             UPFRONT PAYMENT INVOICE             INVOICE

345 Vassar Street                                                INVOICE DATE:
Cambridge, Massachusetts 02139                                   JUNE 1, 2005
Tel. (617) 679-5517
Fax: (617) 679-5542
                                                                 INVOICE NO.: 1

BILL TO:                                     FOR:
                                             Research Collaboration Upfront
Novartis International Pharmaceutical Ltd.    payment
"Hurst Holme", 12 Trott Road
Att.: Mr. Emil Bock
P.O. Box HM 2899
Hamilton, HM LX
Bermuda

<TABLE>
<CAPTION>
                            DESCRIPTION                            AMOUNT (USD)
----------------------------------------------------------------   -------------
<S>                                                                <C>
Upfront payment pursuant to Section 3.2 of the Research            $4,000,000.00
Collaboration and Option Agreement dated May 31, 2005.

        PLEASE REMIT BY WIRE TRANSFER WITHIN 60 DAYS TO:
                Citibank
                ABA 021000089
                Bear Stearns
                A/C: 09253186
                For further credit to: Hybridon
                For further credit to account # 220-03084
                                                                   -------------
                                                           TOTAL   $4,000,000.00
                                                                   =============
</TABLE>

If you have any questions concerning this invoice, contact Bob Anderson at 617
-679-5517 or by e -mail at randersen@hybridon.com.

                        BEST REGARDS,
                        /s/ SUDHIR AGRAWAL
                        SUDHIR AGRAWAL

cc: Novartis Institutes for BioMedical Research (Attn.: Reto Wittwer)