Document:

Exhibit 10.1

                      LINE OF CREDIT AND SECURITY AGREEMENT

         This Agreement (this "Agreement") is made effective as of July 10, 2000
(the "Effective Date"), by and between those persons executing this Agreement as
lenders ("Lenders") and Hybridon, Inc. ("Borrower"), a Delaware corporation with
its principal place of business at 155 Fortune Boulevard, Milford,
Massachusetts.

                                   BACKGROUND

         This Agreement is made in light of the following Background:

A.   As of December 31, 1996, Borrower entered into a non-revolving term loan
     with Silicon Valley Bank which was evidenced, in part, by that certain Loan
     and Security Agreement dated as of December 31, 1996 (the "Subordinate Loan
     Agreement").

B.   On or about November 20, 1998, Forum Capital Markets, LLC ("Forum"),
     Delaware State Employees Retirement Fund, Declaration of Trust for the
     Defined Benefit Plans of ICI American Holdings Inc., Declaration of Trust
     for the Defined Benefit Plans of Zeneca Holdings Inc., The J.W. McConnell
     Family Foundation and General Motors Employees Domestic Group Trust (said
     trusts, foundation and fund being referred to collectively as the "Pecks
     Parties"; Forum and the Pecks Parties are collectively referred to as the
     "Subordinate Lenders") purchased Silicon Valley Bank's interest in the
     credit facility evidenced by the Subordinate Loan Agreement.

C.   On or about December 13, 1999, various persons loaned the principal amount
     of $7.6 million to Borrower, which loans were evidenced by Borrower's 8%
     convertible promissory notes, due November 30, 2002 (the "1999 Notes").

D.   In connection with the issuance of the 1999 Notes, Borrower, Subordinate
     Lenders and those persons who from time to time hold the 1999 Notes
     (collectively, the "Senior Lenders") entered into a Subordination and
     Intercreditor Agreement (the "Intercreditor Agreement"), pursuant to which
     the Subordinate Lenders agreed to subordinate the obligations of Borrower
     under the Subordinate Loan Agreement and the collateral securing such
     obligations to the Borrower's obligations under the 1999 Notes.

E.   Borrower has entered into negotiations with Boston Biosystems, Inc.
     ("BBI"), to sell certain of Borrower's assets to BBI upon terms and under
     conditions set forth in an Asset Purchase Agreement (the "BBI Agreement")
     between Borrower and BBI (the "BBI Transaction").

F.   In order to fund its operations pending the closing of the BBI Transaction,
     Borrower may require additional funds. Lenders are collectively willing to
     enter into a line of credit arrangement with Borrower, pursuant to which
     Lenders would commit to advance such funds, in an aggregate amount not to
     exceed Two Million and no/100 Dollars, from time to

<PAGE>

     time upon Borrower's request, on the terms and subject to the conditions
     set forth in this Agreement. Each Lender, by execution of this Agreement,
     in confirming his, her or its willingness to advance a proportionate amount
     of such funds, in an amount not to exceed the individual maximum indicated
     below such Lender's name on the signature page to this Agreement (the
     Lender's "Commitment").

                                    AGREEMENT

         NOW, THEREFORE, in consideration of the promises set forth herein,
Borrower and Lenders severally but not jointly hereby agree as follows:

1.       DEFINITIONS. In addition to the definitions set forth elsewhere in this
Agreement, the following terms shall have the following meanings, giving effect
to any numerical differences:

         1.1. "Borrower's Liabilities": All obligations and liabilities of
Borrower to Lenders (including without limitation all debts, claims, and
indebtedness) whether primary, secondary, direct, contingent, fixed or
otherwise, heretofore, now and/or from time to time hereafter owing, due or
payable, however evidenced, created, incurred, acquired or owing and however
arising, whether under the Loan Documents or operation of law or otherwise.

         1.2. "Charges": All national, Federal, state, county, city, municipal
and/or other governmental (or any instrumentality, division, agency, body or
department thereof, including without limitation the Pension Benefit Guaranty
Corporation) taxes, levies, assessments, charges, Liens, claims or encumbrances
upon and/or relating to the Collateral, Borrower's Liabilities, Borrower's
business, Borrower's ownership and/or use of any of its assets, Borrower's
income and/or gross receipts and/or Borrower's ownership and/or use of any of
its material assets.

         1.3. "Collateral" shall have the meaning ascribed in Section 4.1,
below.

         1.4. "Common Stock" shall mean the Borrower's Common Stock, $0.001 par
value per share.

         1.5. "Conversion Price" shall equal $1.08 per Share.

         1.6. "Indebtedness": With respect to any Person, at a particular time:
(a) indebtedness for borrowed money or for the deferred purchase price of
property or services in respect of which such Person is liable, contingently or
otherwise, as obligor, guarantor or otherwise or any commitment by which such
Person assures a creditor against loss; (b) obligations under leases which shall
have been or should be, in accordance with generally accepted accounting
principals, recorded as capital leases in respect of which obligations such
Person is liable, contingently or otherwise, as obligor, guarantor or otherwise,
or in respect of which obligations such Person assures a creditor against loss;
and (c) any obligations and liabilities of such Person with respect to unfunded
vested benefits under any "employee benefit plan" or with respect to withdrawal
liabilities to a "multiemployer plan," as such terms are defined under ERISA.

                                       2

<PAGE>

         1.7. "Lien": With respect to any asset, any mortgage, pledge, Charge,
hypothecation, judgment lien or similar legal process, title retention lien or
other lien or security interest or encumbrance of any kind in respect of such
asset. For the purposes of this Agreement, a Person shall be deemed to own,
subject to a Lien, any asset which it has acquired or holds subject to the
interest of a vendor or lessor under any conditional sale agreement, capital
lease or other title retention agreement relating to such asset.

         1.8. "Lender's Percentage" shall, as to any Lender equal that
percentage which Lender's Commitment bears to the total commitments of
$2,000,000.

         1.9. "Lenders' Representative" shall initially mean Youssef El-Zein (a
representative designated by Pillar Investments Ltd.) or, from time to time, a
successor representative chosen by the holders of a majority (measured by dollar
amount) of the Borrowers Obligations hereunder, outstanding from time to time.

         1.10. "Loan Document": The Notes, this Agreement and each and every
other agreement, document, assignment, certificate, statement, instrument or
other written matter, now or at any time hereafter delivered to any Lender to
evidence or secure liabilities and/or obligations of Borrower to Lenders,
whether now or hereafter existing, arising or created, whether executed by or on
behalf of Borrower or any other Person, together with all amendments,
modifications, supplements, restatements, supplements, extensions and
restatements or replacements thereof or thereto.

         1.11. "Person": Any individual, sole proprietorship, partnership, joint
venture, trust, unincorporated organization, association, limited liability
company, corporation, institution, entity, party or government (whether
national, Federal, state, county, city, municipal or otherwise, including
without limitation any instrumentality, division, agency, body or department
thereof).

         1.12. "Subsidiary": With respect to any Person, any corporation of
which more than fifty percent (50%) of the outstanding capital stock having
ordinary voting power to elect a majority of the board of directors of such
corporation (irrespective of whether at the time stock of any other class or
classes of such corporation shall have or might have voting power by reason of
the happening of any contingency) is at the time, directly or indirectly, owned
by such Person.

         1.13. "Unmatured Default": Any event which with the passage of time,
the giving of notice or both would be an Event of Default hereunder or under any
other Loan Document.

         1.14. All financial terms used herein, unless otherwise defined herein,
shall have the meaning ascribed to such term in accordance with generally
accepted accounting terms.

2.       LOANS.

         2.1. Amount. Lenders agree severally but not jointly, on the terms and
conditions of this Agreement, to make loans to Borrower in an aggregate
principal amount at any one time outstanding up to but not exceeding $2,000,000
(the "Loans") and in the individual maximum

                                       3

<PAGE>

amounts indicated on their respective signature pages (which names and amounts
shall be aggregated onto Schedule 2.1). The Loans made by Lenders to Borrower
pursuant to this Agreement may or may not (at the sole and absolute discretion
of Lenders' Representative) be evidenced by notes or other instruments issued or
made by Borrower to Lender (the "Notes"). Subject to the provisions hereof,
Borrower may borrow the Loans at any time or from time to time between the
Effective Date and September 30, 2000, subject to compliance with the
requirements of this Section 2. The outstanding principal amount of the Loans
shall bear interest at a rate equal to eight percent (8%) per annum computed for
the actual number of days elapsed on the basis of a 360-day year. In computing
interest on the Loans, (i) the date of funding shall be included and (ii) the
date of payment shall be excluded.

         2.2. Manner of Borrowing. Borrower shall give Lenders' Representative
written, telegraphic or facsimile notice (the "Draw Notice") executed by a
Designated Person (as defined below), specifying (a) the amount to be disbursed,
which amount shall not be greater, at any one time, than the difference between
$2,000,000, minus the then outstanding principal amount of all Loans theretofore
made hereunder, (b) the date upon which Borrower request such amounts be
disbursed to it (which date shall be not less than seven (7) calendar days after
the date of delivery of the Draw Notice) and (c) Borrower's wire transfer
instructions. Lenders' Representative shall immediately forward the Draw Notice
to each Lender. Within two business days following receipt by each Lender of a
Draw Notice in compliance with this Section 2, each such Lender shall disburse
the Lender's Percentage of the requested funds to an account specified by
Lenders' Representative. Lenders' Representative, in turn, shall upon receipt of
funds from all Lenders, remit the funds to Borrower in care of the account
specified in the Draw Notice. Prior to or concurrently with the execution
hereof, Borrower shall certify to Lender the officer or officers of Borrower who
are authorized to request advances (each a "Designated Person"), together with
true signatures of such officer or officers, and Lenders' Representative may
conclusively rely on such certification until it shall receive notice in writing
to the contrary.

         2.3. Term; Conversion. Lender's obligation to make Loans to Borrower
hereunder shall terminate on the earlier of (i) September 30, 2000 and (ii) the
date on which the BBI Transaction is consummated (the "Maturity Date"). On the
Maturity Date, each Lender may elect in its respective sole discretion either to
(a) require Borrower to convert the unpaid principal balance, plus all interest
earned, under the Loans into shares of Borrower's Common Stock at the Conversion
Price; provided, that in the event that a fractional interest in a share of
Borrower's Common Stock would be deliverable to Lender upon any such conversion
of the Fixed Loan, that number of shares of Common Stock deliverable to Lender
shall be rounded to the nearest whole or (b) demand repayment of all principal
and interest on the Loans.

         2.4. Use of Proceeds. Borrower shall use the Loan Proceeds to fund its
working capital needs.

3.       CONDITIONS OF LENDING.

         3.1. Conditions Precedent to Initial Advance. Prior to or
contemporaneously with the making of the initial advance of funds, Lender's
obligation to make the Loan is subject to the satisfaction of the following
conditions precedent:

                                       4

<PAGE>

                  (a) Fees and Expenses. Borrower shall have paid all fees owed
         to Lenders and Lenders' Representative, including, but not limited to,
         an arrangement fee of $20,000 due to Lenders' Representative, and
         reimbursed Lender for all expenses due and payable hereunder on or
         before the date hereof including, but not limited to, reasonable legal
         fees not to exceed $10,000;

                  (b) Issuance of Warrants. Borrower shall have issued to
         Lenders' Representative warrants to purchase up to 500,000 shares of
         Borrower's Common Stock exercisable at the Conversion Price. In
         addition, Borrower shall have issued to the various Lenders, in
         proportion to their respective Lender's Percentages, warrants to
         purchase up to an aggregate of 1,000,000 shares of Borrower's Common
         Stock, exercisable at the Conversion Price. All such warrants shall be
         exercisable for a three-year period, running from the Maturity Date.

                  (c) Documents. Lender shall have received the Loan Documents,
         each in form and substance satisfactory to Lender, and all of the
         transactions contemplated by each such document shall have been
         consummated or each condition contemplated by each such document shall
         have been satisfied.

                  (d) Financing Statements. The applicable Form UCC-1 and UCC-2
         financing statements related to the Collateral shall have been executed
         and delivered to Lenders' Representative for filing in all
         jurisdictions that Lenders' Representative deems necessary or
         advisable.

                  (e) Internal Approvals. Certified copies of resolutions of
         Borrower's Board of Directors approving the execution and delivery of
         and the consummation of the transactions contemplated by the Loan
         Documents and all other documents or instruments to be executed and
         delivered in conjunction herewith and therewith by Borrower.

                  (f) Amendment of Intercreditor Agreement. Borrower, the Senior
         Lenders and the Subordinate Lenders shall have executed an amendment to
         the Intercreditor Agreement, providing that Borrower's Obligations
         shall have a priority of repayment and a security interest in the
         Collateral, that are in each case pari passu with those of the Senior
         Lenders, and Lenders hereunder shall be added as parties to the
         Intercreditor Agreement.

                  (g) BBI Arrangements. Borrower and BBI shall have entered into
         a final and binding BBI Agreement.

                  (h) Other Documents. Such other documents as Lender may
         reasonably request, including Registration Rights Agreements covering
         the shares of Common stock issuable upon conversion of the Notes or
         exercise of the Warrants..

         3.2. Additional Conditions. The obligation of Lender to make each
advance of a Loan hereunder is subject to the following conditions precedent:

                                       5

<PAGE>

                  (a) no Event of Default or Unmatured Default shall have
         occurred and be continuing;

                  (b) all representations and warranties of Borrower set forth
         herein, or in any other Loan Document shall be true on and as of the
         date of the making of such Loan with the same force and effect as if
         such representation or warranty was made on and as of such date;

                  (c) Borrower shall have duly performed and complied with all
         applicable agreements, covenants and conditions hereunder;

                  (d) no change in the business condition or operations, or
         results of operations, performance, properties or prospects, financial
         or otherwise, of Borrower shall have occurred which is deemed, in the
         reasonable discretion of Lenders' Representative, to have a material
         adverse effect on Borrower;

                  (e) no litigation or proceeding shall be outstanding or have
         been instituted or threatened which Lenders' Representative determines
         to be material against Borrower or any of Borrower's assets; and

                  (f) the BBI Agreement shall remain in full force and effect
         and shall not have been canceled or terminated and the Buyer under the
         BBI Agreement shall not have overtly asserted that any condition to
         Buyer's obligation to close, as set forth in Section 7(a) of the BBI
         Agreement and not waived by Buyer, shall not have been satisfied.

4.       COLLATERAL.

         4.1. Grant of Security Interest. To secure the prompt payment to
Lenders of Borrower's Liabilities and the prompt, full and faithful performance
by Borrower of all of the provisions to be kept, observed or performed by
Borrower under the Loan Documents, Borrower grants to Lenders' Representative,
as representative of all Lenders hereunder, a security interest in and to, and
collaterally assigns to Lender, all of the Collateral (as that term is defined
in the Subordinate Loan Agreement), on the terms and subject to the conditions
set forth in the Subordinate Loan Agreement, as amended. In addition to the
Collateral as specified in the Subordinate Loan Agreement, the term "Collateral"
shall include all rights of Borrower as "Seller" under the BBI Agreement,
including a right to enforce Borrower's rights against BBI, in the event of a
default by BBI in its purchase obligations. Borrower shall make appropriate
entries upon its financial statements and its books and records disclosing
Lender's security interest in the Collateral.

         4.2. Perfection of Security Interest. Borrower shall execute and
deliver to Lenders' Representative, at the request of Lenders' Representative,
all agreements, instruments and documents that Lenders' Representative
reasonably may request, in form and substance acceptable to Lender, to perfect
and maintain perfected Lender's security interest in the Collateral

                                       6

<PAGE>

and to consummate the transactions contemplated in or by the Loan Documents.
Borrower agrees that a carbon, photographic or photostatic copy, or other
reproduction, of this Agreement or of any financing statement, shall be
sufficient as a financing statement.

         4.3. Inspection. Lenders' Representative shall have the right, at any
time during Borrower's usual business hours, to inspect the Collateral and all
related records (and the premises upon which it is located) and to verify the
amount and condition of, or any other matter relating to, the Collateral.

         4.4. Priority. Borrower warrants and represents to and covenants with
Lenders that Lenders' security interest in the Collateral is now and at all
times hereafter, until Borrower's Liabilities have been indefeasibly paid and
performed in full, shall be perfected and have a first priority pari passu with
the Senior Lenders.

         4.5. Location of Collateral. The office and/or locations where Borrower
keeps the Collateral are specified in Exhibit 4.4 hereto and Borrower shall not
remove such Collateral from such locations and shall not keep any of such
Collateral at any other office or location unless Borrower gives Lenders'
Representative written notice thereof prior thereto and the same is within the
continental United States of America. Borrower, by written notice delivered to
Lenders' Representative prior thereto, shall advise Lenders of Borrower's
opening of any new office or place of business or its closing of any existing
office or place of business.

         4.6. Proceeds of Collateral. At the request of Lenders' Representative,
during the pendency of an Event of Default, and subject to the terms and
conditions of the Intercreditor Agreement, Borrower shall receive, as the sole
and exclusive property of Lenders and as trustee for Lenders, all monies,
checks, notes, drafts and all other payment for and/or proceeds of Collateral
which come into the possession or under the control of Borrower and immediately
upon receipt thereof, Borrower shall remit the same (or cause the same to be
remitted), in kind, to Lenders or at Lenders' Representative's direction.

         4.7. Event of Default. Upon demand or an Event of Default or any
Unmatured Default, Lenders' Representative may, subject to the terms and
conditions of the Intercreditor Agreement, take control of, in any manner, and
may endorse Borrower's name to any of the items of payment of proceeds described
in Paragraph 4.6 above and, pursuant to the provisions of this Agreement,
Lenders shall apply the same to and on account of Borrower's Liabilities.

         5. COVENANTS. At all times during the term hereof, Borrower agrees
that, unless Lenders' Representative shall otherwise consent in writing:

         5.1. Affirmative Covenants.

         (a)      Insurance.

                  (i)     Borrower will at all times maintain or cause to be
         maintained on Borrower's tangible assets, insurance against such risks
         ordinarily insured against by other owners or users of such properties
         in similar businesses similarly situated

                                       7
<PAGE>

         and in any event the following: (1) insurance covering Borrower's
         tangible assets in the event of fire, lightning, windstorm, vandalism,
         malicious mischief and all other risks normally covered by "Special
         Perils" coverage policies in an amount, subject to commercially
         reasonable deductibles, equal to 100% of the replacement value thereof;
         (2) comprehensive general public liability insurance in such minimum
         combined single limit amount as Lenders' Representative shall require,
         in its reasonable discretion, subject to commercially reasonable
         deductibles; and (3) Worker's Compensation and employer's liability
         insurance covering Borrower's employees in such amounts as is required
         by law.

                  (ii)    Upon the request of Lenders' Representative, Borrower
         shall deliver to Lenders' Representative a certified copy of each
         policy of insurance and evidence of payment of all premiums therefor.
         Lenders shall be named as an "additional named insured" on all policies
         of liability insurance. Such endorsement shall provide that the
         insurance companies will give Lenders' Representative prior notice
         before any such policy shall be materially modified or canceled and
         that no act or default of Borrower or any other Person (other than
         Lenders' Representative) shall affect the right of Lenders to recover
         under such policy in case of loss or damage.

         (b)       Payment of Charges and Debts. Borrower shall pay when due all
         Indebtedness and all Charges at or before maturity or before the same
         becomes delinquent; provided that Borrower shall not be required to pay
         any Indebtedness or Charges, on the conditions that (i) Borrower, in
         good faith, shall be contesting the same in an appropriate proceeding,
         (ii) enforcement thereof against any assets of Borrower shall be
         stayed; and (iii) appropriate reserves therefor shall have been
         established on the records of Borrower in accordance with generally
         accepted accounting principles.

         5.2. Negative Covenants.

                  (a) Limitations on Indebtedness. Borrower shall not, without
         the prior written consent of Lenders' Representative, incur
         Indebtedness (including guarantying or otherwise becoming liable with
         respect to the obligations of any other Person or any agreement to
         maintain the net worth of any other Person) except for: (i)
         Indebtedness incurred under this Agreement, (ii) Indebtedness, existing
         on the date hereof, disclosed to Lenders on the Financial Statements,
         and (iii) obligations or liabilities created or arising under any lease
         or trade payable incurred or arising in the ordinary course of
         business.

                  (b) Sale; Liens. Until Borrower's Liabilities have been
         indefeasibly paid and performed in full, Borrower shall not grant,
         permit or suffer any Lien upon any of Borrower's assets to arise after
         the date hereof, except Liens in the ordinary course of business.
         Borrower shall not sell, assign, transfer or convey all or
         substantially all of its assets, except pursuant to the BBI
         Transaction.

                  (c) Attachment; Receivers. Borrower shall not permit or
         suffer: (i) any levy, attachment

                                       8
<PAGE>

         or restraint to be made affecting any of its assets which such levy,
         attachment or restraint has not been released within a reasonable
         period of time, or (ii) any receiver, trustee or assignee for the
         benefit of creditors, or any other custodian to be appointed to take
         possession of all or any of Borrower's assets.

                  (d) Merger; Change Capital Structure. Except with respect to
         the BBI Transaction or with the prior written consent of the Lenders'
         Representative, Borrower shall not: (i) make any material change in
         Borrower's capital structure or in any of its business objectives,
         purposes and operations which might in any way adversely affect the
         repayment of the Loan, or (ii), without prior notice to Lender, change
         its corporate name.

                  (e) Distributions; Borrower's Stock. If an Event of Default or
         an Unmatured Default exists or would be created thereby, Borrower shall
         not declare or pay dividends upon any of Borrower's stock or redeem,
         retire, purchase or otherwise acquire, directly or indirectly, any of
         Borrower's stock or other evidence of ownership interest or make any
         distributions or transfers of Borrower's property or assets in respect
         of its stock to any Persons. Notwithstanding the prior sentence,
         Borrower shall be permitted to make interest payments on outstanding
         debt instruments through the issuance of additional debt or equity
         securities, and to cancel securities outstanding as of the Effective
         Date which are later tendered to the Borrower for conversion.

         6. REPRESENTATIONS AND WARRANTIES OF BORROWER.

         6.1. General Representations. Borrower represents, covenants and
warrants as follows:

                  (a) Organization. Borrower is duly organized and existing as a
         corporation in good standing under the laws of the State of Delaware
         and is qualified to do business and is in good standing in each other
         state where the nature and extent of the business transacted by it or
         the ownership of its assets makes such qualification necessary.
         Borrower has no Subsidiaries or ERISA Affiliates.

                  (b) Corporate Authority; Due Diligence. The execution,
         delivery and performance by Borrower of this Agreement and each of the
         other Loan Documents are: (i) within Borrower's corporate powers; (ii)
         have been duly authorized by all necessary corporate action of
         Borrower; (iii) do not contravene (1) the Certificate of Incorporation
         or by-laws of Borrower or (2) any law or contractual restriction
         binding on or affecting Borrower; and (iv) do not result in or require
         the creation of any Lien upon or with respect to any of its properties
         (other than the Liens contemplated by this Agreement and the other Loan
         Documents). No authorization, approval or other action by, and no
         notice to or filing with, any governmental authority or regulatory body
         is required for the due execution, delivery and performance by Borrower
         of this Agreement and the other Loan Documents to which Borrower is a
         party.

                  (c) Binding Obligations. This Agreement and the other Loan
         Documents to which Borrower is a party are legal, valid and binding
         obligations of Borrower, and are enforceable against Borrower, in
         accordance with their respective terms, except as such

                                       9
<PAGE>

         enforceability may be limited by bankruptcy, insolvency,
         reorganization, moratorium or other laws relating to or limiting
         creditors' rights or equitable principles generally.

                  (d) Litigation. There is no pending action or proceeding
         before any court, governmental agency or arbitrator against or directly
         involving Borrower and, to the best of Borrower's knowledge, there is
         no threatened action or proceeding affecting Borrower or any of its
         assets before any court, governmental agency or arbitrator (i) which,
         in any case, may materially and adversely affect the financial
         condition or operations of Borrower, (ii) which seeks to restrain or
         would otherwise have a material adverse effect on the transactions
         contemplated herein, or (iii) which would affect the validity or
         enforceability of this Agreement or the other Loan Documents.

                  (e) Title; Liens. Borrower has good, indefeasible and
         merchantable title to and ownership of the Collateral. None of the
         Collateral is subject to any Lien, except for (i) Liens arising under
         the Subordinate Loan Agreement and the 1999 Notes, (ii) Liens arising
         in the ordinary course of business and (iii) Liens reflected on the
         Financial Statements delivered by Borrower to Lenders prior to the date
         of the initial funding of the Loan.

                  (f) Business Purpose; Investment Company. Borrower shall use
         the proceeds of all loans solely for business purposes and consistently
         with all applicable laws and statutes. Borrower is not an "investment
         company" or a company "controlled" by an "investment company," within
         the meaning of the Investment Company Act of 1940, as amended. Borrower
         is not engaged principally, or as one of Borrower's important
         activities, in the business of extending credit for the purpose of
         purchasing or carrying margin stock (within the meaning of Regulation U
         of the Board of Governors of the Federal Reserve System), and will not
         use the proceeds of any Loan hereunder so as to violate Regulation U as
         it may be amended or interpreted from time to time by the Board of
         Governors of the Federal Reserve System.

                  (g) Tax Returns. Borrower has filed or caused to be filed all
         Federal, state and local tax reports and returns which are required to
         be filed, and has paid or caused to be paid all taxes as shown on said
         returns or which are due or on any assessment received by it, to the
         extent that such taxes have become due.

                  (h) Financial Condition. The balance sheets and statements of
         income and retained earnings of Borrower for the year ended December
         31, 1999 and for the period ended March 31, 2000 (collectively, the
         "Financial Statements"), are complete and correct and fairly represent
         the financial condition of Borrower as at the dates of said financial
         statements and the results of its operations for the periods ending on
         said dates. Borrower has previously furnished Lenders' Representative
         with copies of the Financial Statements. Borrower has no material
         contingent obligations, liabilities for taxes, long-term leases, or
         unusual forward or long-term commitments not disclosed by, or reserved
         against in Financial Statements or the notes thereto; and at the
         present time there are no material unrealized or anticipated losses
         from any unfavorable commitments not disclosed by, or reserved against
         in said the Financial Statements or the notes thereto. The

                                       10
<PAGE>

         Financial Statements were prepared in accordance with generally
         accepted accounting principles consistently applied throughout the
         period involved. Since the date of the latest of such Financial
         Statements, there has been no material adverse change in the financial
         condition of Borrower from that set forth in the Financial Statements
         as at that date.

                  (i) Default in Other Agreements. Borrower is not in default
         (other than defaults which have been waived in writing, as listed on
         Schedule 6.1 hereof) in the payment or performance of any of its
         obligations or in the performance of any mortgage, indenture, lease,
         contract or other agreement, instrument or undertaking to which it is a
         party or by which it or any of its assets may be bound, which default
         would have a material and adverse effect on the business, operations,
         assets or condition, financial or otherwise, of Borrower, either
         individually or taken as a whole. Borrower is not in default under any
         order, award or decree of any court, arbitrator, or governmental
         authority binding upon or affecting it or by which any of its assets
         may be bound or affected which default would have a material adverse
         effect on the business, operations, assets or condition, financial or
         otherwise, of Borrower, either individually or taken as a whole, and no
         such order, award or decree adversely affects the ability of Borrower
         to carry on its business as currently conducted or the ability of
         Borrower to perform its obligations under this Agreement and the other
         Loan Documents to which it is a party.

                  (j) Business Prospects. There is no fact known to Borrower
         which materially adversely affects or in the future may (so far as
         Borrower can now foresee) materially adversely affect the business,
         property, assets or financial condition of Borrower which has not been
         set forth in this Agreement or in the other Loan Documents, prior to
         the date hereof in connection with the transactions contemplated
         hereby.

                  (k) Licenses. Borrower possesses adequate licenses, patents,
         patent applications, copyrights, service marks, trademarks and trade
         names to conduct its business as heretofore conducted and as intended
         to be hereafter conducted by it and all such items are owned by or
         licensed to Borrower free and clear of conflicting claims or uses of
         any other Person, except where the failure to possess or own such
         licenses, patents, patent applications, copyrights, service marks and
         trademarks would not have a material adverse effect on the business of
         Borrower.

         6.2. Compliance with ERISA. Neither Borrower, nor any member of its
controlled group (as defined under Section 414 of the Internal Revenue Code),
has any obligations with respect to any Employee Benefit Plan, as defined under
Section 3(3) of ERISA. Borrower and its controlled group (a) are in compliance
with ERISA in all material respects, (b) have paid or accrued all contributions
owed pursuant to the terms of each applicable plan, (c) neither participate in
nor sponsor any Employee Benefit Plan with an actuarial present value of accrued
plan benefits, on a termination basis, that exceeds the net assets available for
such benefits, as determined using the actuarial assumptions set forth in the
actuarial reports for each such plan's most recently completed plan year, and
(d) offer no welfare benefit plans with accrued unfunded liabilities to any of
its retirees. Borrower and its controlled group agree to (a) keep in full force
and effect any and all Employee Benefit Plans that are presently in existence or
may, from time

                                       11
<PAGE>

to time, come into existence, unless such plans can be terminated without
material liability to Borrower, (b) make contributions to all Employee Benefit
Plans in a timely manner and in a sufficient amount to comply with the
requirements of ERISA, and (c) comply with all material requirements of ERISA so
as to avoid any event that would have a material adverse effect on Borrower.

         6.3. Solvency. Borrower has capital sufficient to carry on its business
and transactions and all businesses and transactions in which it is about to
engage and is able to pay its debts as they mature and Borrower owns property
the fair saleable value of which is greater than the amount required to pay
Borrower's Liabilities. No transfer of property is being made and no
Indebtedness is being incurred in connection with the transactions contemplated
by this Agreement with the intent to hinder, delay or defraud either present or
future creditors of Borrower.

         6.4. Compliance with Laws and Regulations. The execution and delivery
by Borrower of this Agreement and the other Loan Documents and the performance
of Borrower's obligations hereunder and thereunder are not in contravention of
any law or laws. Borrower is and, at all times during the term hereof shall be,
in substantial compliance with all laws, orders, regulations and ordinances of
all Federal, foreign, state and local governmental authorities relating to its
business, operations and assets and no failure to fully comply shall,
individually or in the aggregate, have a material adverse effect on Borrower's
business, operations, condition (financial or otherwise) or prospects.

         6.5. Survival. The foregoing representations, covenants and warranties
of Borrower shall be continuing and shall survive the execution and delivery of
this Agreement and the other Loan Documents and shall be true and correct at all
times prior to the payment in full of all indebtedness under this Agreements and
other Loan Documents. By submitting to Bank any request for an advance, Borrower
shall be deemed to have restated each and every representation and warranty as
of the date of such request. Borrower hereby affirmatively covenants to take all
actions or to avoid taking any action which would render any representation or
warranty untrue or inaccurate at any time during the term hereof.

         7. DEFAULT; REMEDIES.

         7.1. Events of Default. Any one or more of the following events is an
"Event of Default" under this Agreement, and the term "Event of Default,"
wherever used herein, means any one of the following events:

              (a)     if Borrower shall fail to pay any payment of principal,
         interest or any other amount due to Lenders under the Notes or any
         other Loan Document within ten (10) days of the date due and payable;
         or if any representation or warranty made by Borrower herein or in any
         other Loan Document shall prove at any time to be, in any material
         respect, incorrect or misleading as of the date made; or;

              (b)     if Borrower breaches the covenants set forth in Sections
         5.2 or if Borrower shall default in the performance of any other
         covenant hereunder (not constituting an

                                       12
<PAGE>

         Event of Default under any other clause of this Section 7) and such
         default shall continue unremedied for a period of thirty (30) days
         after Lenders' Representative shall have delivered written notice
         thereof to Borrower;

              (c)     any event of default shall have occurred under the terms
         of the Notes or any other Loan Document (which event is not an Event of
         Default under any other provision of this Section 7.1) which is not
         cured within the time period provided therefor, if any;

              (d)     if a petition under any section or chapter of the
         Bankruptcy Reform Act of 1978, as amended, or any similar law or
         regulation shall be filed by Borrower or if Borrower shall make an
         assignment for the benefit of creditors or if any case or proceeding is
         filed by Borrower for dissolution or liquidation or if Borrower is
         enjoined, restrained or in any way prevented by court order from
         conducting all or any material part of its business affairs or if a
         petition under any section or chapter of the Bankruptcy Reform Act of
         1978, as amended, or any similar law or regulation is filed against
         Borrower or if any case or proceeding is filed against Borrower for
         dissolution or liquidation and such injunction, restraint or petition
         is not dismissed or stayed within thirty (30) days after the entry or
         filing thereof;

              (e)     if an application is made by any Person other than
         Borrower for the appointment of a receiver, trustee, or custodian for
         any portion of Borrower's assets and the same is not dismissed or
         stayed within thirty (30) days after the application therefor; or

              (f)     Lenders' Representative shall have reason to believe that
         the prospect of payment of the Loans or the performance of any of
         Borrower's obligations under this or any other agreement with any of
         the Lenders is impaired.

         7.2. Remedies. Upon the occurrence of an Event of Default and during
the continuation thereof, Lender, in its sole and absolute discretion, may: (a)
declare all of Borrower's Liabilities immediately due and payable, terminate all
commitments hereunder and declare all liabilities under the other Loan Documents
immediately due and payable; and (b) exercise any and all rights and remedies
under the other Loan Documents, at law or at equity, provided however that any
such actions shall only be taken in strict conformity with the terms and
conditions of the Intercreditor Agreement. Lenders' failure at any time or times
hereafter to require strict performance by Borrower of any provision of this
Agreement shall not waive, affect or diminish any right to Lenders thereafter to
demand strict compliance and performance therewith.

         8. GENERAL.

         8.1. Designation of Lenders' Representative as Agent. Each Lender, by
his, her or its execution of this Agreement, hereby irrevocably designates the
Lenders' Representative (including any duly chosen successor Lenders'
Representative) to act as agent and representative of such Lender, with respect
to this Agreement and as specified in the other Operative

                                       13
<PAGE>

Documents. Each Lender hereby irrevocably authorizes the Lenders' Representative
to take such action on its behalf under the provisions of this Agreement and the
other Operative Documents and any other instruments and agreements referred to
herein or therein and to exercise such powers and to perform such duties
hereunder and thereunder as are specifically delegated to, or required of, the
Lenders' Representative by the terms hereof or thereof and such other powers as
are reasonably incidental thereto. Each Lender, on behalf of itself and future
holders of the Notes issued to such Lender, hereby authorizes and directs the
Lenders' Representative, from time to time in the Lenders' Representative's
discretion to take any action and promptly to execute and deliver on its behalf
any document or instrument that the Company may reasonably request to effect,
confirm or evidence the provisions of this Agreement.

         8.2. Notices. Any notice, consent, waiver or other notification
required or permitted to be given under this Agreement shall be in writing and
shall be personally delivered or mailed, first-class postage prepaid, or sent by
recognized overnight courier express mail service or by facsimile transmission
(confirmed electronically or in writing). A written notice shall be deemed to
have been given to the recipient party on the earlier of: (a) the date it shall
be delivered to the address required hereunder; (b) the date delivery shall have
been refused at the address required hereunder; and (c) with respect to notices
sent by mail, the date as of which the postal service shall have indicated such
notice to be undeliverable at the address required hereunder. Any and all
notices shall be mailed to the following addresses:

         If to Lenders:

                           c/o Pillar Investments Ltd., as  Representative
                           28 Avenue de Messine
                           Paris, FRANCE 75008
                           Attn:    Youssef El-Zein
                           Fax:  011 331 44 136 464

                           With a Copy to:
                           Sachnoff & Weaver, Ltd.
                           30 South Wacker Drive,
                           29th Floor
                           Chicago, Illinois 60606-7484
                           Attention: Lance Rodgers, Esq.
                           Fax:     (312) 207-6400

         If to Borrower:

                           Hybridon, Inc.
                           155 Fortune Boulevard
                           Milford, Massachusetts
                           Attention: Robert G. Andersen
                           Fax: 508/482-7692

                           With a Copy to:

                                       14

<PAGE>

                           Holland & Knight
                           One Beacon Street
                           Boston, MA
                           Attention: James Pollock, Esq.
                           Fax: (617) 720-0325

or at such other address or addresses as the party addressed may from time to
time designate in writing by similar means. Any such notice shall be deemed
given when actually received by the party to whom notice is intended to be given
or actually delivered at the address of the party as shown above.

         8.3. Amendments, Changes, and Modifications. This Agreement may not be
amended, changed, modified, altered or terminated without the written consent of
Lenders' Representative.

         8.4. Indemnification. Borrower shall indemnify, defend and hold Lenders
harmless from and against any and all losses, costs, liabilities, damages and
expenses (including attorney's fees) of every kind, nature and description
resulting or arising from: (a) the breach of any material representation,
warranty or covenant herein or in any other Loan Document; (b) any third party
claims relating to Borrower's business or any act or omission of Borrower; (c)
any material breach or alleged breach by Borrower of any applicable law, order,
regulation or ordinance of any Federal, foreign, state or local governmental
authorities.

         8.5. Release. Borrower hereby acknowledges and agrees that Lenders
shall not be liable to Borrower and hereby releases and discharges Lenders from
any liability, for any and all losses, costs, expenses (including attorneys'
fees), damages, judgments, claims and causes of action, paid, incurred or
sustained by Borrower as a result of or relating to any action, or failure or
refusal to act, on the part of Lenders or any other party with respect to this
Agreement, or the documents and transactions related hereto or thereto or
contemplated hereby or thereby, including, without limitation, the exercise by
Lenders or any third party of any of its rights or remedies pursuant to any of
such documents; provided that nothing herein shall be deemed a waiver or release
of any claim arising after the date hereof out of Lenders' gross negligence or
willful misconduct.

         8.6. Choice of Law. Borrower and Lenders hereby agree that this
Agreement shall be governed by the internal laws of the Commonwealth of
Massachusetts, without regard to any choice of law principles.

         8.7. Interpretation. If a term or provision of this Agreement shall be
held invalid, illegal or unenforceable, all other terms and provision hereof
shall ,to the maximum extent possible, remain in effect.

         8.8. Waiver of Jury Trial. BORROWER AND LENDERS EACH HEREBY KNOWINGLY,
VOLUNTARILY AND INTENTIONALLY WAIVES THE RIGHT TO A TRIAL BY JURY IN RESPECT OF
ANY LITIGATION BASED HEREON, ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS
AGREEMENT OR ANY OTHER LOAN DOCUMENT OR ANY COURSE OF CONDUCT, COURSE OF
DEALINGS, STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF EITHER PARTY.
BORROWER HEREBY EXPRESSLY ACKNOWLEDGES THIS WAIVER IS A MATERIAL INDUCEMENT FOR
LENDER TO ACCEPT THIS AGREEMENT AND TO MAKE THE LOAN EVIDENCED HEREBY AND BY THE
OTHER LOAN DOCUMENTS.

                                       15

<PAGE>

          IN WITNESS WHEREOF, the parties have executed this Agreement effective
as of the date set forth above.

BORROWER:

HYBRIDON, INC.

By:________________________________
         (Signature)

Print Name of Signatory:_____________________________

Its:________________________________
         (Print Title or Status of Signatory)

LENDERS:

Name of Lender:         ______________________________________

By:                     ______________________________________
                           (Signature)

Print Name of Signatory:_______________________________________

Its:                       ____________________________________
                           (Print Title or Status of Signatory)

Dollar of Loan Commitment: $______________

                                       16Exhibit 10.2

                           FIRST AMENDED AND RESTATED
                    SUBORDINATION AND INTERCREDITOR AGREEMENT

         THIS FIRST AMENDED AND RESTATED SUBORDINATION AND INTERCREDITOR
AGREEMENT (this "Agreement") is effective as of July 10, 2000 (the "Effective
Date") by and among Hybridon, Inc., a Delaware corporation ("Borrower"), those
persons who from time to time hold the 8% senior notes (described herein) of the
Borrower due November 30, 2002 (collectively, the "Senior Noteholders"), those
persons who have executed as lenders that certain Line of Credit and Security
Agreement (the "June Loan Agreement"), dated as of July 10, 2000, between such
lenders and Borrower (collectively, the "Senior Lenders", and together with the
Senior Noteholders, the "Senior Security Holders"), and Founders Financial Group
("Founders"), Delaware State Employees Retirement Fund, Declaration of Trust for
the Defined Benefit Plans of ICI American Holdings Inc., Declaration of Trust
for the Defined Benefit Plans of Zeneca Holdings Inc., The J.W. McConnell Family
Foundation and General Motors Employees Domestic Group Trust (said trusts,
foundation and fund being referred to collectively as the "Pecks Parties";
Founders and the Pecks Parties are collectively referred to as the "Subordinate
Lenders"). This Agreement amends and restates that certain Subordination and
Intercreditor Agreement, effective as of December 7, 1999, by and among the
Borrower, the Senior Noteholders and the Subordinate Lenders (the "Original
Agreement").

                                    RECITALS:

         A.     Senior Security Holders have agreed to extend financial
accommodations to Borrower pursuant to the terms of the Senior Loan Documents
(defined below).

         B.     Subordinate Lenders are also shareholders of Borrower and have
representatives on Borrower's Board of Directors.

         C.     As of December 31, 1996, Borrower entered into a non-revolving
term loan with Silicon Valley Bank (the "Bank") which was evidenced, in part, by
that certain Loan and Security Agreement dated as of December 31, 1996 (the
"Subordinate Loan Agreement").

         D.     As security for the financial accommodations made pursuant to
the Subordinate Loan Agreement, Borrower granted to Bank a security interest in
certain assets of Borrower described more fully in the Subordinate Loan
Agreement and herein.

         E.     Founders is the succeessor in interest to an investment
portfolio formerly held by Forum Capital Markets, LLC ("Forum"). On or about
November 20, 1998, Forum and the Pecks Parties purchased the interests of Bank
in credit facility evidenced and secured by the Subordinate Loan Agreement and
the Subordinate Loan Documents (defined herein).

         F.     When the Senior Noteholders made their advances to the Borrower,
they required that Borrower and Subordinate Lenders agree to subordinate certain
obligations of Borrower to

<PAGE>

Subordinate Lenders. To reflect that agreement, Senior Noteholders, Forum and
the Pecks Parties entered into the Original Agreement.

         F.     Borrower wishes to enter into an agreement with Boston
Biosystems, Inc. ("BBI"), to sell to BBI certain of Borrower's assets (the
"Transferred Assets") which are the subject of liens and security interests held
by the Senior Security Holders and the Subordinate Lenders upon terms and under
conditions set forth in an Asset Purchase Agreement between Borrower and BBI
(the "BBI Transaction").

         G.     To close the BBI Transaction, Borrower wishes to obtain from the
Senior Security Holders and the Subordinate Lenders a release of the Senior
Security Holders' and the Subordinate Lenders' entire respective right, title
and interest in and to their security interests in the Transferred Assets.

         H.     As a condition to making their financial accommodations, Senior
Lenders have required, and the Borrower, Senior Noteholders and Subordinate
Lenders have agreed, that the obligations of Borrower to Subordinate Lenders be
further subordinated, that the Borrower's obligations to the Senior Lender's be
pari passu with its obligations to the Senior Noteholders and that other
processes be agreed to, as more fully set forth herein.

         NOW, THEREFORE, in consideration of the foregoing Recitals and the
mutual covenants and agreements set forth herein, and for other good and
valuable consideration, the mutuality, receipt and sufficiency of which hereby
are acknowledged, and intending to be legally bound, the parties hereto agree as
follows:

1.       DEFINITIONS.

Certain terms used herein and not otherwise defined (including capitalized terms
used in the foregoing Recitals) shall have the following meanings:

          An "Acceleration" shall mean the occurrence of any acceleration of the
principal and interest under any of the Borrower Obligations.

         "Borrower's Public Filings" shall mean the periodic filings on Forms
10-K, 10-Q and 8-K, as filed from time to time with the U.S. Securities and
Exchange Commission.

         "Borrower Obligations" means the Senior Obligations or the Subordinate
Obligations, as the context requires.

         "Committee Event" shall have the meaning set forth in Section 2.2(a).

         "Default" shall mean any Default or "default" under and as defined in
the Senior Loan Documents or the Subordinate Loan Documents, as the context
requires.

                                       2

<PAGE>

         "Event of Default" means any Senior Event of Default or Subordinate
Event of Default, as the context requires.

         "Founders Representative" means Harold L. Purkey, or a successor chosen
by Founders.

         "Lenders Committee" shall have the meaning set forth in Section 2.2(a).

         "Payment in Full" or "Paid in Full" or any similar term(s) with respect
to any Borrower Obligation means (a) the indefeasible satisfaction and final
payment in full of such Borrower Obligation in cash or cash equivalents
reasonably acceptable to the payee and the termination of any obligation on the
part of the holder of such Borrower Obligation to make any loans or to afford
any financial accommodation to Borrower and the full and timely performance of
all other obligations to the holder of such Borrower Obligation or (b) in the
case of any Borrower Obligation consisting of contingent obligations (including
without limitation contingent obligations in respect of letters of credit or
other indemnifications under the Subordinate Loan Documents), the setting apart
of cash sufficient to discharge such portion of such Borrower Obligation in an
account for the exclusive benefit of the holders thereof, in which account such
holders shall be granted by Borrower a first priority perfected security
interest in a manner acceptable to such holders, which payment or perfected
security interest shall have been retained by the holders, in the case of each
of (a) and (b) above, for a period of time in excess of all applicable
preference or other similar periods under applicable bankruptcy, insolvency or
creditors' rights laws.

         "Pecks Representative" means Arthur W. Berry or a successor chosen by
the holders of a majority of the interests held by the Pecks Parties.

         "Remedy Notification" means the written notification by Subordinate
Lenders to Senior Noteholders and/or Senior Lenders or by Senior Noteholders
and/or Senior Lenders to Subordinate Lenders of such party's desire to exercise
a Remedy following the occurrence of an Event of Default.

         "Remedy" means any the following actions by either Senior Lenders or
Subordinate Lenders:

         (i)      the exercise of any rights or remedies they may have under the
     Subordinate Loan Documents or otherwise (other than a declaration of an
     Acceleration);

         (ii)     the commencement or joinder with any other creditors of
     Borrower in commencing any bankruptcy, reorganization, receivership or
     insolvency proceeding against Borrower; or

         (iii)    the commencement of any action or proceeding against Borrower
     to enforce or collect any Borrower Obligation, to obtain possession of
     property of Borrower, to exercise

                                       3

<PAGE>

     control over property of Borrower or to create, perfect or enforce any
     lien against property of Borrower.

         "Senior Event of Default" means any Event of Default under and as
defined in the Senior Loan Documents.

         "Senior Security Holders' Representative" means Youssef El-Zein (a
representative designated by Pillar Investments Ltd.) or a successor
representative chosen by the holders of a majority (measured by dollar amount)
of the Senior Obligations, outstanding from time to time.

         "Senior Loan Documents" means (i) the Borrower's 8% notes, due November
30, 2002, issued to Senior Noteholders, (ii) the Subscription Agreements between
Borrower and each Senior Noteholder, (iii) the Warrant Agreements between
Borrower and the Senior Noteholders, (iv) the Line of Credit and Security
Agreement, dated as of July 10, 2000, between the Senior Lenders and Borrower
(the "Line of Credit"), and (v) all other instruments, agreements and documents
which create, evidence or secure the Senior Obligations from time to time
(including but not limited to any promissory notes, security agreements, pledge
agreements, hypothecation agreements, mortgages, financing statements, and all
other agreements of any type whatsoever), delivered by Borrower to Senior
Lenders, as such may be amended, modified, supplemented, restated, replaced or
refinanced (in any such case with any Senior Lender) from time to time,
including all such extensions, renewals, refinancings or refundings thereof,
whether or not the principal amount is increased.

         "Senior Obligations" means all obligations of the Borrower under the
Senior Loan Documents including but not limited to principal, interest, fees and
all other amounts owing to Senior Lenders under the Senior Loan Documents, from
time to time. Notwithstanding the foregoing, the Senior Obligations shall not
include any principal owed by the Borrower to the Senior Lenders in excess of
$10,000,000 except with the consent of the Senior Security Holders'
Representative and the Subordinate Lenders' Representatives.

         "Subordinate Debt" means all principal, interest, fees and other
amounts owing to Subordinate Lenders under the Subordinate Loan Documents from
time to time, whether in respect of principal, interest or otherwise.

         "Subordinate Event of Default" means any Event of Default under and as
defined in the Subordinate Loan Documents.

         "Subordinate Lenders' Representatives" shall mean the Pecks
Representative and the Founders Representative.

         "Subordinate Loan Agreement" shall have the meaning set forth in the
Recitals.

         "Subordinate Loan Documents" means Subordinate Loan Agreement and all
other instruments, agreements and documents which create, evidence or secure the
Subordinate Obligations from time to time.

                                       4

<PAGE>

         "Subordinate Obligations" means all obligations of Borrower under the
Subordinate Loan Documents including but not limited to principal, interest,
fees and all other amounts owing to Subordinate Lenders under the Subordinate
Loan Documents, from time to time.

2.       SUBORDINATION AND INTERCREDITOR PROVISIONS.

         2.1.     Subordination.

         (a) Subordinate Lenders hereby consent to Borrower obtaining certain
financial accommodations from Senior Security Holders, all on a senior secured
basis.

         (b) Senior Security Holders hereby acknowledge that Subordinate Lenders
have been previously granted a security interest in certain of the assets of
Borrower. Subordinate Lenders hereby acknowledge and agree that they are willing
to and hereby do subordinate the Subordinate Obligations and the collateral
securing such obligations to the Senior Obligations.

         (c) Borrower and Subordinate Lenders each hereby represents and
warrants to Senior Security Holders that a true, accurate and complete copy of
all Subordinate Loan Documents has been either filed as an exhibit to Borrower's
Public Filings or otherwise provided to Senior Security Holders' Representative
or its counsel in writing, and that none of the Subordinate Loan Documents has
been amended or modified in any way from the versions so filed or provided.

         (d) Subordinate Lenders agree, for themselves and each future holder of
the Subordinate Obligations, that: (i) subject to the terms hereof, the
Subordinate Debt is and shall be expressly subordinate and junior in right of
payment to all Senior Obligations until the Senior Obligations have been Paid in
Full; (ii) Subordinate Lenders shall not accept additional security or further
collateral to support the payment or performance of the Subordinate Debt, unless
the Senior Security Holders are granted a lien or security interest in such
additional collateral, and such lien or security interest in favor of Senior
Security Holders is senior to the lien of the Subordinate Lenders; and (iii)
Senior Security Holders have advanced funds in reliance upon the subordination
of the Subordinate Debt and the collateral securing such debt to the Senior
Obligations.

         2.2.     Lenders Committee.

         (a) Senior Security Holders and Subordinate Lenders hereby agree to
constitute a "Lenders Committee" immediately upon the first to occur of the
following: (i) the occurrence of an Acceleration, or (ii) the occurrence of a
Remedy Notification (a "Committee Event").

         (b) The Lenders Committee shall have three members which shall be
comprised of the Senior Security Holders' Representative and the two Subordinate
Lenders' Representatives. Any matter which, under the terms of this Agreement or
otherwise, requires a vote or action by

                                       5

<PAGE>

the Lenders Committee, shall require the affirmative votes of a majority of the
members of the Lenders Committee.

         (c) From and after its formation following a Committee Event, the
Lenders Committee shall be charged solely with liquidating any collateral held
by any of the Senior Security Holders or Subordinate Lenders by obtaining
possession of or exerting control over such collateral, and perfecting or
enforcing liens of the Senior Security Holders and the Subordinate Lenders
against such collateral. Borrower and the Lenders Committee shall disburse any
proceeds of such liquidation according to the priorities set by this Agreement.

         (d) From and after any Event of Default, neither Senior Security
Holders nor Subordinate Lenders may exercise a Remedy without first providing
not less that ten (10) days advance written notice to the other Lenders of its
desire to so exercise a Remedy (the "Remedy Notification"). Subsequent to the
delivery of the Remedy Notification and the resulting formation of the Lenders
Committee, then, until the date the Senior Obligations are Paid in Full,
Subordinate Lenders shall not exercise any Remedy without either (a) direction
or approval by the Lenders Committee or (b) express approval provided herein.
Similarly, at any time prior to the date the Subordinate Obligations are Paid in
Full, Senior Security Holders shall not exercise any Remedy, without either (a)
direction or approval by the Lenders Committee or (b) express approval provided
herein.

         (e) If any insolvency, bankruptcy, receivership, liquidation,
reorganization or other similar proceedings are commenced by or against Borrower
or its property, if any proceedings for involuntary liquidation, dissolution or
other winding up of Borrower whether or not involving insolvency or bankruptcy
are commenced by or against Borrower (collectively, any "Reorganization
Proceedings"), then Senior Security Holders shall be entitled in any such
Reorganization Proceedings to receive Payment in Full of all Senior Obligations
before Subordinate Lenders are entitled in any the Reorganization Proceedings to
receive any payment on account of the Subordinate Obligations. In any
Reorganization Proceedings, any payment or distribution of any kind or
character, whether in cash or in property to which Subordinate Lenders would be
entitled on account of the Subordinate Obligations but for the provisions of
this Agreement, shall be delivered to Senior Security Holders to the extent
necessary to make Payment in Full of all Senior Obligations remaining unpaid,
after giving effect to any concurrent payment or distribution to or for Senior
Security Holders in respect thereof. Subject to the Payment-in-Full of all
Senior Obligations, the holders of Subordinate Obligations shall be subrogated
to the rights of the holders of the Senior Obligations (to the extent of
payments or distributions made to holders of Senior Obligations pursuant to the
foregoing sentence or Section 2.3(b)) to receive payments or distributions of
the assets of Borrower applicable to the Senior Obligations. No such payments or
distributions applicable to the Senior Obligations shall, as between Borrower
and its creditors, other than the holders of Borrower Obligations, be deemed to
be a payment by Borrower to or on account of the Subordinate Obligations; and
for the purposes of such subrogation, no payments or distributions to the
holders of Senior Obligations to which the holders of Subordinate Obligations
would be entitled except for the provisions of this section shall, as between
Borrower and its creditors, other than the holders of Borrower Obligations, be
deemed to be a payment by Borrower to or on account of the Senior Obligations.

                                       6

<PAGE>

         (f) Notwithstanding anything to the contrary contained herein,
Subordinate Lenders may, in any proceedings described in Section 2.2 (e), in the
name of Subordinate Lenders, file claims, proofs of claims and other instruments
of similar character necessary to enforce the obligations of Borrower in respect
of the Subordinate Obligations. Notwithstanding anything to the contrary
contained herein, Senior Security Holders may, in any proceedings described in
Section 2.2 (e), in the name of Senior Security Holders, file claims, proofs of
claims and other instruments of similar character necessary to enforce the
obligations of Borrower in respect of the Senior Obligations. Neither this
Section 2.2(f) nor any other provision hereof shall be construed to give
Subordinate Lenders any right to vote any Borrower Obligation held by Senior
Security Holders, any related claim or any portion of such claim, whether in
connection with any resolution, arrangement, plan or reorganization, compromise,
settlement, election of trustees or otherwise, all such votes, as to Senior
Obligations to be made solely on the direction of the Senior Security Holders.
Neither this Section 2.2(f) nor any other provision hereof shall be construed to
give Senior Security Holders any right to vote any Borrower Obligation held by
Subordinate Lenders, any related claim or any portion of such claim, whether in
connection with any resolution, arrangement, plan or reorganization, compromise,
settlement, election of trustees or otherwise, all such votes, as to Subordinate
Obligations to be made solely on the direction of the Subordinate Security
Holders.

         2.3.     Payments of Borrower Obligations.

         (a) The following provisions shall govern Subordinate Lenders' right to
receive and Borrower's right and obligation to pay any amount due and owing
under the Subordinate Loan Documents:

                  (i) Provided that the Subordinate Lenders' Representatives
                  shall not have been notified that an Acceleration shall have
                  occurred and be continuing or would be created thereby under
                  the terms of any of the Senior Loan Documents, Subordinate
                  Lenders may receive and Borrower may pay interest only at the
                  interest rate set forth in the Subordinate Loan Documents as
                  of the Effective Date, when due and owing on an unaccelerated
                  basis and not at a rate applicable upon default.

                  (ii) Except as expressly permitted pursuant to Section
                  2.3(a)(i), Subordinate Lenders shall not be entitled to
                  receive or retain any direct or indirect payment (in cash,
                  cash-equivalents, property, by set-off or otherwise) of or on
                  account of any Subordinate Obligation at any time prior to
                  Payment in Full of the Senior Obligations; provided, however,
                  Borrower may deliver to Subordinate Lenders' Representatives,
                  at any time (including during the occurrence of an Event of
                  Default under any of the Senior Loan Documents and/or the
                  Subordinate Loan Documents), the proceeds from the sale of
                  Subordinate Lender's Collateral, which sale shall be made in a
                  manner directed or approved by the Lenders Committee. Except
                  as expressly permitted pursuant to Section 2.3(a)(i) and (ii),
                  at any time that any of the Senior Obligations is outstanding,
                  Borrower shall not make and

                                       7

<PAGE>

                  Subordinate Lenders shall not receive or accept any payment
                  (in cash, cash-equivalents, property, by set-off, "bid in" of
                  debt in a disposition of collateral or otherwise) of any kind
                  or nature with respect to the Subordinate Obligations.

         (b) If Subordinate Lenders receive any payment with respect to the
Subordinate Obligations which Subordinate Lenders are not permitted to receive
and retain pursuant to this Agreement, then such payment shall be held in trust
for the benefit of, and shall be paid over promptly to Senior Security Holders,
for application to the payment of the Senior Obligations, in such order of
priority as Senior Security Holders' Representative shall determine. If
Subordinate Lenders pay over any payment or distribution as provided above, then
such payment or distribution shall be deemed to have been made by Borrower
directly to Senior Security Holders and not to Subordinate Lenders and no
Subordinate Obligation shall be discharged by reason of its receipt of any
payment or distribution which is so paid over to Senior Security Holders.

         (c) To the extent necessary for Senior Security Holders to realize the
benefits of the subordination of the Subordinate Obligations provided for
herein, Subordinate Lenders shall execute and deliver to Senior Security
Holders' Representative such instruments or documents (together with such
assignments or endorsements as Senior Security Holders shall deem necessary), as
are consistent with the terms of this Agreement and are reasonably requested by
Senior Security Holders' Representative.

         (d) In the event Subordinate Lenders at any time incur any obligation
to pay money to Borrower, Subordinate Lenders hereby irrevocably agree that they
shall pay such obligation in cash or cash equivalents in accordance with the
terms of the document or instrument governing such obligation without deduction
or set-off against the Subordinate Obligations.

         2.4. Borrower's Obligations Absolute. The provisions of this Agreement
are solely for the benefit of Borrower, Senior Security Holders and Subordinate
Lenders for the purpose of defining the relative rights of the parties thereto.
Nothing herein shall impair, as between Borrower and any other party hereto, the
obligations of Borrower, which are unconditional and absolute, to Senior
Security Holders and to Subordinate Lenders, respectively.

         2.5. Transfers. Any Senior Security Holder or any Subordinate Lender
may sell, assign or otherwise transfer, in whole or in part, any of the Borrower
Obligations or any interest therein to any other person or entity, but only on
the express condition that the transferee of the Borrower Obligations shall
expressly acknowledge to the other parties to this Agreement, in writing, that
it agrees to be bound by all of the terms hereof. Senior Security Holders and
Subordinate Lenders each hereby represents and warrants to the others that as of
the execution date hereof neither Senior Security Holders nor Subordinate
Lenders has transferred or entered into any agreement or understanding with a
proposed transferee that they will transfer any of the Borrower Obligations.

         2.6. Liens Subordinate. (a) Subordinate Lenders agree that any liens
upon Borrower's assets securing payment of the Subordinated Debt, now or
hereafter existing, are and shall be and remain inferior and subordinate to any
liens securing payment of the Senior

                                       8

<PAGE>

Obligations regardless of whether such encumbrances in favor of the Subordinated
Lenders or Senior Security Holders presently exist or are hereafter created or
attach.

         (b) Senior Security Holders and Subordinate Lenders hereby agree that,
after the Lenders Committee is constituted, the Lenders Committee may file any
or all lien releases, UCC releases, and termination statements on behalf of the
Senior Security Holders and the Subordinate Lenders at any time Borrower, or any
successor, assign or agent of Borrower, proposes a sale of any asset that is
approved by the Lenders Committee. In furtherance thereof, the Senior Security
Holders and the Subordinate Lenders agree to execute, acknowledge and deliver
any lien releases, UCC-3 termination statements or such additional instruments
or documents as may be reasonably necessary to confirm the foregoing within
three (3) business days of the request therefor by Lenders Committee.

         2.7.     Additional Representations and Warranties. Subordinate Lenders
and Borrower represent and warrant to Senior Security Holders that:

         (a)      as of the date hereof, the total principal amount of the
Subordinate Obligations is $7.3 million plus accrued but unpaid interest;

         (b)      except as indicated in Borrower's Public Filings or disclosed
in writing to the Senior Security Holders' Representative and its counsel, which
writing is hereby made a part hereof, as of the date hereof, to the best of
their knowledge, after due enquiry, no default or Event of Default, or event
which with notice or passage of time or both would constitute an Event of
Default exists or has occurred under the Subordinate Loan Documents;

         (c)      Subordinate Lenders are collectively the exclusive legal and
beneficial owner of all of the Subordinate Obligations;

         (d)      except as indicated in Borrower's Public Filings or disclosed
in writing to the Senior Security Holders' Representative and its counsel, which
writing is hereby made a part of this Agreement, none of the Subordinate
Obligations is subject to any lien, security interest (other than Subordinate
Lender's Collateral), financing statements, subordination, assignment or other
claim; and

         (e)      this Agreement constitutes the legal, valid and binding
obligations of Subordinate Lenders, enforceable in accordance with its terms.

         2.8.     Legends. Subordinate Lenders agree that any instrument at any
time evidencing the Subordinate Obligations, or any portion thereof, shall be
permanently marked on its face with a legend conspicuously indicating that
payment thereof is subordinate in right of payment to the Senior Obligations and
subject to the terms and conditions of this Agreement, and after being so marked
certified copies thereof shall be delivered to Senior Security Holders. In the
event any legend or endorsement is omitted, Senior Security Holders or any of
their representatives, officers or employees are hereby irrevocably authorized
on behalf of Subordinate Lenders to make the same. No specific legend, further
assignment or endorsement or delivery of notes,

                                       9

<PAGE>

guarantees or instruments shall be necessary to subject any Subordinate
Obligations to the subordination thereof contained in this Agreement.

         2.9.     Waiver of Covenant. Subordinate Lenders hereby waive any
breaches or defaults arising from Borrower's failure to maintain compliance with
Section 6.9 of the Subordinate Loan Agreement, entitled "Minimum Liquidity",
such waiver to remain in effect so long as any amounts of Senior Obligations
remain outstanding,

3.       AGREEMENT BY BORROWER.

         (a) Borrower hereby acknowledges and agrees to the foregoing terms and
provisions, and agrees that the provisions hereof will bind Borrower, together
with its successors and assigns.

         (b) Borrower acknowledges and agrees that: (i) in the event of a breach
by Borrower or Subordinate Lenders of any of the terms and provisions contained
in this Agreement, such a breach shall constitute an Event of Default, as
defined in and under the Senior Loan Documents; and (ii) it will execute and
deliver such additional documents and take such additional action as may be
necessary or desirable in the opinion of either Subordinate Lenders or Senior
Security Holders to effectuate the provisions and purposes of this Agreement.

4.       CONSENT AND RELEASE.

         (a) Subordinate Lenders and Senior Noteholders each hereby consent to
the execution of, and the parties' respective performance under, the June Loan
Agreement, including: (i) the characterization of the Senior Lenders, in
addition to the Senior Noteholders, as Senior Security Holders hereunder; (ii)
the grant to the Senior Lenders of a security interest in the Collateral (as
defined in the June Loan Agreement), which interest shall be subject to the
terms and conditions of this Agreement; (iii) the repayment of the amounts due
the Senior Lenders and the Senior Noteholders on a pari passu basis; and (iv)
the concomitant further subordination of the Subordinate Lenders' security
interest in certain of the assets of Borrower to the security interest of the
Senior Lenders (in addition to the Senior Noteholders).

         (b) Subject to the terms and conditions set forth in paragraphs (b) and
(c) below, upon the closing of the BBI Transaction, the Subordinated Lenders and
the Senior Security Holders each agree to forever release and surrender, in
accordance with Section 2.6(b) hereof, all right, title and interest in any
security interest such Subordinated Lender or Senior Security Holder may have in
the Transferred Assets (the "BBI Security Interest"). Subordinate Lenders and
Senior Security Holders agree to execute and file a UCC-3 Partial Release, and
all other documents reasonably requested by Borrower, to effect as a matter of
public record the release contemplated by this

         (c) As consideration for the release and surrender of the BBI Security
Interest, concurrently with the closing of the BBI Transaction, Borrower shall
invest Five Million Dollars ($5,000,000) in a segregated, interest-bearing
instrument (the "Money Market Instrument") and shall deliver and pledge the
Money Market Instrument to the Subordinated Lenders and the

                                       10

<PAGE>

Senior Security Holders as collateral securing the payment of the Subordinated
Obligations and the Senior Obligations. The pledge of the Money Market
Instrument shall be pursuant to a written Pledge Agreement to be entered into by
and between the Borrower and the Senior Security Holder's Representative, as
collateral agent for the Senior Security Holders and the Subordinated Lenders.
The Money Market Instrument shall be deemed to be "Collateral" under the
Subordinated Loan Documents and the Senior Loan Documents, and shall be subject
to and governed by the terms and conditions of this Agreement, the Senior Loan
Documents and the Subordinate Loan Documents pertaining to Borrower's
collateral. Borrower shall be entitled to receive any and all interest or other
income generated by the Money Market Instrument for so long as no event of
default on Borrower's part has occurred under the Subordinated Loan Documents or
the Senior Loan Documents.

         (d) To the extent that, and on each occasion that, the Senior Security
Holders convert all or a portion of the principal amount and interest of debt
held by them into capital stock of the Borrower pursuant to conversion rights
under the Senior Loan Documents, in the amount of One Million Dollars
($1,000,000) or more in the aggregate: (i) the pledge shall be released as to a
portion of the the Money Market Instrument equal to the principal amount of debt
so converted; (ii) Borrower shall be entitled to reduce the amount of to use the
released funds as it sees fit; and (iii) the Subordinated Lenders and the Senior
Security Holders shall execute and deliver such instruments as may be necessary
to effectuate the reduction and release.

5.       MISCELLANEOUS.

         5.1. Notices. Any and all notices given in connection with this
Agreement shall be deemed adequately given only if in writing and addressed to
the party for whom such notices are intended at the address set forth below. All
notices shall be sent by personal delivery, Federal Express or other over-night
messenger service, first class registered or certified mail, postage prepaid,
return receipt requested or by other means at least as fast and reliable as
first class mail. A written notice shall be deemed to have been given to the
recipient party on the earlier of (a) the date it shall be delivered to the
address required by this Agreement; (b) the date delivery shall have been
refused at the address required by this Agreement; or (c) with respect to
notices sent by mail, the date as of which the postal service shall have
indicated such notice to be undeliverable at the address required by this
Agreement. Any and all notices referred to in this Agreement, or which either
party desires to give to the other, shall be addressed as follows:

         if to Borrower:        Hybridon, Inc.
                                155 Fortune Blvd.
                                Milford, MA 01757
                                Attn.: President

         with a copy to:        Holland & Knight
                                One Beacon Street
                                Boston, MA.
                                Attn.: James Pollock, Esq.

                                       11

<PAGE>

         if to Senior Security Holders:   Pillar Investments Ltd. Representative
                                          28 Avenue de Messine
                                          Paris, FRANCE 75008
                                          Attn:    Youssef El-Zein

         with a copy to:                  Sachnoff & Weaver, Ltd.
                                          30 South Wacker Drive
                                          Suite 2900
                                          Chicago, Illinois 60606
                                          Attn:    Lance R. Rodgers, Esq.

     if to Subordinate Lenders:           Pecks Management
                                          1 Rockefeller Plaza, Suite 900
                                          New York, NY  10020
                                          Attn: Arthur W. Berry
                                               and
                                          Founders Financial Group
                                          53 Forest Avenue
                                          Old Greenwich, CT  06870
                                          Attn: Harold L. Purkey

The above addresses may be changed by notice of such change, mailed as provided
herein, to the last address designated.

         5.2. No Fiduciary Duty. Nothing in this Agreement shall be construed to
create or impose upon any Senior Security Holders any fiduciary duty to any
Subordinate Lender, or any other implied obligation to act or refrain from
acting with respect to Borrower or the Senior Obligations or the collateral
security securing the Senior Obligations in any manner contrary to what any
Senior Security Holders may determine is in its own best interests. Similarly,
nothing in this Agreement shall be construed to create or impose upon any
Subordinate Lender any fiduciary duty to any Senior Security Holders, or any
other implied obligation to act or refrain from acting with respect to Borrower
or the Subordinate Obligations or the collateral security securing the
Subordinate Obligations in any manner contrary to what any Subordinate Lender
may determine is in its own best interests.

         5.3. Notice of Default. In addition to any other notices which may be
required hereunder, Subordinate Lenders shall give written notice to Senior
Security Holders' Representative, promptly after they become aware of the
occurrence of: (a) an Event of Default under the terms of the Subordinate Loan
Documents; (b) the cure of any such Event of Default; (c) the payment in full of
the Subordinate Debt; (d) any Acceleration of the Subordinate Debt; and (e) any
action or proceeding instituted against Borrower on account of any Event of
Default.

                                       12

<PAGE>

         5.4. Successors; Continuing Effect.

         (a) This Agreement is being entered into for the benefit of, and shall
be binding upon, Borrower, each Senior Security Holders and each Subordinate
Lender and their respective successors and assigns, including each subsequent or
additional holder of Senior Obligations, or Subordinate Debt, and any
participant (whether now existing or hereafter arising) in the Senior
Obligations. The terms "Senior Security Holders" and "Subordinate Lenders" shall
include, respectively, any such subsequent or additional holder of or
participant in Senior Obligations or Subordinate Obligations whenever the
context permits. This Agreement shall inure to the benefit of and be enforceable
by any future holder or holders of the Borrower Obligations or any part of any
of the same; provided that, nothing contained in this Section 5.4 shall be
deemed to permit the transfer of the Subordinate Obligations in violation of the
provisions of Section 2.5.

         (b) Senior Security Holders reserve the right to grant participations
in, or otherwise sell, assign, transfer or negotiate all or any part of, or any
interest in, the Senior Obligations and the Collateral securing same. In
connection with any participation or other transfer or assignment, Senior
Security Holders (i) may disclose to such assignee, participant or other
transferee or assignee all documents and information which Senior Security
Holders now or hereafter may have relating to the Senior Obligations or the
Collateral, and (ii) shall disclose to such participant or other transferee or
assignee the existence and terms and conditions of this Agreement.

         5.5. Amendments. This Agreement may be amended only by a written
instrument executed by holders of a majorities in interest of each of the Senior
Obligations and the Subordinate Obligations and, if such amendment affects
Borrower, by Borrower.

         5.6. Term. This Agreement shall remain in full force and effect until
the Payment in Full of the Senior Obligations.

         5.7. Waivers. No waiver shall be deemed to be made by any party of any
of its rights hereunder unless the same shall be in writing and then only with
respect to the specific instance involved, and no such waiver shall impair or
offset the rights of the waiving party or the obligations of the party benefited
by such waiver in any other respect or at any other time.

         5.8. Governing Law. This Agreement, including the validity hereof and
the rights and obligations of the parties hereunder, shall be governed by and
construed and enforced in accordance with the laws of the Commonwealth of
Massachusetts.

         5.9. The Borrower May Not Impair Subordination. No right of Senior
Security Holders or Subordinate Lenders to enforce the subordination created
hereby shall be impaired by any act or failure to act by Borrower or by the
failure by Borrower to comply with this Agreement, regardless of any knowledge
which any Senior Security Holders or any Subordinate Lender may have or be
otherwise charged with.

         5.10. Specific Performance. The parties hereto acknowledge that legal
remedies may be inadequate and therefore Senior Security Holders and Subordinate
Lenders are hereby authorized to demand specific performance of the provisions
of this Agreement at any time when Borrower, Senior Security Holders or
Subordinate Lenders shall have failed to comply with any provision

                                       13

<PAGE>

hereof. Each party hereto hereby irrevocably waives any defense based on the
adequacy of a remedy at law that might be asserted as a bar to such remedy of
specific performance.

         5.11. Further Actions. After the execution of this Agreement each party
will execute and deliver all such documents and instruments and do all such
other acts and things as may be reasonably necessary to carry out the provisions
of this Agreement.

         5.12. Agreement to Control. If any provision in any document or
instrument relating to the Senior Obligations or the Subordinate Debt differs
with the terms of this Agreement regarding the same or any similar matter, the
provisions of this Agreement shall control and each other provision shall be
interpreted so as to give effect to the provisions of this Agreement.

         5.13. Entire Agreement. This Agreement contains the entire agreement of
the parties with respect to the subject matter hereof and supersedes all prior
written and oral agreements, and all contemporaneous oral agreements, relating
to such matters.

         5.14. Severability. Any provision of this Agreement which is prohibited
or unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining portions hereof or affecting the validity or
enforceability of such provision in any other jurisdiction.

         5.15. Facsimile. For purposes of negotiating and finalizing this
Agreement (including any subsequent amendments thereto), any signed document
transmitted by facsimile machine ("Fax") shall be treated in all manner and
respects as an original document. The signature of any party by Fax shall be
considered for these purposes as an original signature. Any such Fax document
shall be considered to have the same binding legal effect as an original
document, provided that an original of the faxed document was mailed by first
class U.S. Mail or personally delivered to the recipient, on the date of its
transmission with proof of the fax transmission. At the request of any party,
any Fax document subject to this Agreement shall be re-executed by both parties
in an original form. The undersigned parties hereby agree that neither shall
raise the use of the Fax or the fact that any signature or document was
transmitted or communicated through the use of a Fax as a defense to the
formation of this Agreement. This Agreement may be signed in one or more
counterparts, each of which shall be an original, but all of which together
shall constitute one agreement, binding on all of the parties hereto
notwithstanding that all of the parties hereto are not signatories to the same
counterpart. Each of the undersigned parties authorizes the assembly of one or
more original copies of this Agreement through the combination of the several
executed counterpart signature pages with one or more copies of this Agreement,
including the Schedules and Exhibits, if any, to this Agreement. Each such
compilation of this Agreement shall constitute one original of this Agreement.

         5.16.    Consent to Jurisdiction; Waiver of Jury Trial.

         (a) BORROWER, SUBORDINATE LENDERS AND SENIOR SECURITY HOLDERS EACH
HEREBY (i) TO THE EXTENT PERMITTED BY APPLICABLE LAW, IRREVOCABLY SUBMITS TO THE
JURISDICTION OF ANY STATE OR FEDERAL

                                       14

<PAGE>

COURT LOCATED IN BOSTON, MASSACHUSETTS, OVER ANY ACTION OR PROCEEDING TO ENFORCE
OR DEFEND ANY MATTER ARISING FROM OR RELATED TO THIS AGREEMENT; (ii) IRREVOCABLY
WAIVES, TO THE FULLEST EXTENT BORROWER, SUBORDINATE LENDERS AND SENIOR LENDERS
MAY EFFECTIVELY DO SO, THE DEFENSE OF AN INCONVENIENT FORUM TO THE MAINTENANCE
OF ANY SUCH ACTION OR PROCEEDING IN ANY SUCH COURT; (iii) AGREES THAT, TO THE
EXTENT PERMITTED BY APPLICABLE LAW, A FINAL JUDGMENT IN ANY SUCH ACTION OR
PROCEEDING IN ANY SUCH COURT SHALL BE CONCLUSIVE AND MAY BE ENFORCED IN ANY
OTHER JURISDICTION BY SUIT ON THE JUDGMENT OR IN ANY OTHER MANNER PROVIDED BY
LAW; AND (iv) TO THE EXTENT PERMITTED BY APPLICABLE LAW, AGREES NOT TO INSTITUTE
ANY LEGAL ACTION OR PROCEEDING AGAINST ANY PARTY HERETO OR ANY OF PARTY'S
DIRECTORS, OFFICERS, EMPLOYEES, AGENTS OR PROPERTY, CONCERNING ANY MATTER
ARISING OUT OF OR RELATING TO THIS AGREEMENT IN ANY COURT OTHER THAN ONE LOCATED
IN BOSTON, MASSACHUSETTS.

         (b) NOTHING IN THIS SECTION SHALL AFFECT OR IMPAIR SENIOR SECURITY
HOLDERS' OR SUBORDINATE LENDERS' RIGHT TO SERVE LEGAL PROCESS ON BORROWER IN ANY
MANNER PERMITTED BY LAW OR SENIOR SECURITY HOLDERS' OR SUBORDINATE LENDERS'
RIGHT TO BRING ANY ACTION OR PROCEEDING AGAINST BORROWER OR BORROWER'S PROPERTY
IN THE COURTS OF ANY OTHER JURISDICTION.

         (c) BORROWER, SENIOR SECURITY HOLDERS AND SUBORDINATE LENDERS EACH
HEREBY KNOWINGLY, VOLUNTARILY AND INTENTIONALLY WAIVES THE RIGHT TO A TRIAL BY
JURY IN RESPECT OF ANY LITIGATION BASED HEREON, ARISING OUT OF, UNDER OR IN
CONNECTION WITH THIS AGREEMENT OR ANY OTHER LOAN DOCUMENT OR ANY COURSE OF
CONDUCT, COURSE OF DEALINGS, STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS
OF EITHER PARTY. EACH PARTY HERETO HEREBY EXPRESSLY ACKNOWLEDGES THIS WAIVER IS
A MATERIAL INDUCEMENT FOR SENIOR SECURITY HOLDERS TO ENTER INTO THIS AGREEMENT
AND TO MAKE THE LOANS EVIDENCED BY THE SENIOR LOAN DOCUMENTS.

                                       15

<PAGE>

IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Subordination Agreement as of the day, month and year first above written.

                           HYBRIDON, INC.

                           By: /s/ Robert G. Anderson
                              ------------------------------------------
                           Name:  Robert G. Anderson
                           Title: Chief Financial Officer and
                                  Vice President of Operations & Planning

                           SENIOR LENDERS
                               By: Pillar Investments Ltd, Their Representative

                           By:   /s/ Youssef Tel Zein
                              -------------------------------------------
                           Name: Youssef Tel Zein

                           SENIOR NOTEHOLDERS
                               By: Pillar Investments Ltd, Their Representative

                           By:   /s/ Youssef Tel Zein
                              -------------------------------------------
                           Name: Youssef Tel Zein

                           FOUNDERS FINANCIAL GROUP

                           By: /s/ Harold L. Purkey
                              -------------------------------------------
                           Name: Harold L. Purkey
                           Title: Partner

                                       16

<PAGE>

                           DELAWARE STATE EMPLOYEES RETIREMENT
                           FUND     DECLARATION OF TRUST FOR THE DEFINED
                           BENEFIT PLANS OF ICI AMERICAN HOLDINGS INC
                           DECLARATION OF TRUST FOR THE DEFINED
                           BENEFIT PLANS OF ZENECA HOLDINGS INC.
                           THE J.W. MCCONNELL FAMILY FOUNDATION
                           GENERAL MOTORS EMPLOYEES DOMESTIC
                           GROUP TRUST

                                    By: PECKS MANAGEMENT PARTNERS, LTD.

                                    By: /s/ Arthur W. Berry
                                       ----------------------------------
                                    Name:  Arthur W. Berry
                                    Title: Principal

                                       17

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00013-of-00352.parquet"}]]