Execution Copy

                                    AMENDMENT NO. 1 dated as of March 14, 2003
                                    to the U.S. Commercialization Agreement
                                    dated as of April 26, 2002 between Genta
                                    Incorporated ("Genta") and Aventis
                                    Pharmaceuticals Inc. ("Aventis") (as the
                                    same may be amended, supplemented or
                                    otherwise modified, the "U.S.
                                    Commercialization Agreement").

                             INTRODUCTORY STATEMENT

            Reference is made to that certain U.S. Commercialization Agreement
dated as of April 26, 2002 between Genta and Aventis concerning the development
and commercialization of products containing or comprising an antisense compound
known as G3139 (also known as oblimersen sodium).

            In order to facilitate its performance of its obligations under the
U.S. Commercialization Agreement, Genta has requested and Aventis has agreed
that Aventis establish a secured revolving line of credit pursuant to which
Aventis would make advances to Genta from time to time in an aggregate principal
amount, together with all accrued and unpaid interest, not to exceed $40,000,000
at any one time outstanding.

            Accordingly, Genta and Aventis have agreed to amend the U.S.
Commercialization Agreement, all on the terms and subject to the conditions
hereinafter set forth.

            Therefore, the parties hereto hereby agree as follows:

            Section 1. Defined Terms. Capitalized terms used herein and not
otherwise defined herein shall have the meaning given them in the U.S.
Commercialization Agreement.

            Section 2. Amendments to the U.S. Commercialization Agreement.
Subject to the satisfaction of the conditions precedent set forth in Section 3
hereof, the U.S. Commercialization Agreement is hereby amended as of the
Effective Date (as hereinafter defined) as follows:

            (A) Section 1 of the U.S. Commercialization Agreement is hereby
amended by adding the following definitions in the appropriate alphabetical
sequence:

            "Accrued Amount" shall mean, as of any relevant period of time, all
accrued Development Costs owing from Aventis to Genta for the immediately
preceding three full calendar months, net of any amounts owing from Genta to
Aventis for such three month period.

            "Advance" shall have the meaning given such term in Section 19.1
hereof.

            "Advance Default" shall have the meaning given such term in Section
19.8 hereof.
<PAGE>

            "Applicable Law" shall mean all provisions of statutes, rules,
regulations and orders of the United States or foreign governmental bodies or
regulatory agencies applicable to a Person, and all orders and decrees of all
courts and arbitrators in proceedings or actions in which the Person in question
is a party.

            "Borrowing Base" shall mean, at any date for which the amount
thereof is to be determined, an amount equal to the aggregate of (i) (*) of the
Accrued Amount plus (ii) the Over Advance Amount.

            "Borrowing Base Report" shall be as defined in Section 19.1(g)
hereof.

            "Borrowing Certificate" shall be as defined in Section 19.6 hereof.

            "Borrowing Request Date" shall mean the date on which Genta delivers
to Aventis the notice required by Section 19.1(c).

            "Business Day" shall mean any day other than a Saturday, Sunday or
other day on which banks are permitted to close in the States of New York and
New Jersey.

            "Code" shall mean the Internal Revenue Code of 1986, as amended.

            "Collateral" shall have the meaning given such term in the Security
Agreement.

            "Commitment" shall mean the commitment of Aventis to make Advances
to Genta from the Closing Date through the Commitment Termination Date in a
principal amount and together with all accrued and unpaid interest thereon, in
the aggregate, at any one time outstanding not to exceed $40,000,000.

            "Commitment Termination Date" shall mean the earliest to occur of:
(i) the receipt of NDA Approval for the Product, (ii) the giving of notice by
either Genta or Aventis of the termination of this Agreement in accordance with
Section 15 hereof, (iii) the giving of notice by Genta of the termination of the
Commitment, (iv) the termination of the Commitment pursuant to Section 19.8
hereof, (v) an event shall occur which would have a material adverse effect on
the ability of Genta to perform its respective obligations hereunder or under
the Security Agreement, as determined by Aventis in its reasonable good faith
judgement, and (vi) December 31, 2004.

            "Development Cost Report" shall be as defined in Section 19.1(g)
hereof.

            "Dollars" and "$" shall mean lawful money of the United States of
America.

            "Global Supply Agreement" shall mean the Global Supply Agreement
dated as of April 26, 2002 among Genta, Aventis and Aventis Ireland Limited
(formerly Garliston Limited).

            "Governmental Authority" shall mean any federal, state, municipal or
other governmental department, commission, board, bureau, agency or
instrumentality, or any court, in each case whether of the United States or any
foreign jurisdiction.


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<PAGE>

            (*)

            "Maturity Date" shall mean the date that is the earlier of: (i)
acceleration of the Advances upon the occurrence of an Advance Default, or (ii)
six months after any other event that constitutes a Commitment Termination Date.

            "Maximum Advance" shall mean at any time for which it is to be
determined, the lesser of the Commitment or the Borrowing Base.

            "Over Advance Amount" shall mean an amount, determined by Aventis in
its reasonable good faith discretion from time to time but no less frequently
than once at the beginning of each Calendar Quarter, which represents the sum of
(*). Notwithstanding the foregoing, if an event occurs that is reasonably
expected to cause a material change in the Over Advance Amount as most recently
determined by Aventis, then Genta may propose and Aventis shall consider in good
faith a change to the Over Advance Amount.

            "Person" shall mean any natural person, corporation, division of a
corporation, partnership, trust, joint venture, association, company, estate,
unincorporated organization or government or any agency or political subdivision
thereof.

            (*)

            "Security Agreement" shall mean the security agreement between Genta
and Aventis dated as of the date of this Amendment No. 1 to the U.S.
Commercialization Agreement and attached hereto as Exhibit A.

            (B) Section 6.2.1 of the U.S. Commercialization Agreement is hereby
amended by (i) deleting Section 6.2.1(A) in its entirety, (ii) deleting Section
6.2.2 in its entirety and (iii) changing the number "35 million" appearing in
Section 6.2.1(B) to "75 million".

            (C) Section 6.2.3 of the U.S. Commercialization Agreement is hereby
amended by deleting the words "and the same indication may trigger the milestone
payment under Event A (*) and any other Event" appearing in the last sentence
thereof.

            (D) For purposes of clarification, the Parties agree that (*).

            (E) A new Article 19 entitled "Advances to Genta" is hereby added to
the U.S. Commercialization Agreement to read as follows:

ARTICLE 19 ADVANCES TO GENTA

            SECTION 19.1 Advances.

            (a) Aventis agrees, upon the terms and subject to the conditions
hereinafter set forth, to make advances (the "Advances") to Genta in a given
month on any Business Day following the determination of the Borrowing Base for
such month pursuant to Section 19.1(g), and from time to time from the Effective
Date to and including the Commitment Termination Date, each in an amount which
when added to the aggregate principal amount of all Advances


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<PAGE>

then outstanding and all accrued and unpaid interest thereon owed by Genta to
Aventis does not exceed the Maximum Advance. For purposes of clarification, no
Advance shall be made in a given month until the Borrowing Base for such month
has been determined in accordance with Section 19.1(g). Following the
determination of the Borrowing Base for such month, Genta may request Advances
on any Business Day for the remainder of such month, not to exceed the Maximum
Advance.

            (b) Following the determination of the Borrowing Base for a given
month, Advances shall be made at such time as Genta shall request and subject to
the conditions herein set forth, Genta may borrow, repay and reborrow amounts
constituting the Commitment.

            (c) Genta shall give Aventis prior written, telecopier or telephonic
(promptly confirmed in writing) notice of each request for an Advance hereunder
which notice shall be addressed to (*) at 400 Somerset Corporate, Mail Code SC4
525A, Bridgewater, NJ 08807-0912, facsimile no.: (*), telephone no.: (*) with a
copy to (*) at 200 Crossing Blvd, PO Box 6890, Mail Code BX2 709B, Bridgewater,
NJ 08807-6908, facsimile no.: (*), telephone no.: (*). Such notice shall be
irrevocable and to be effective, must be received by Aventis not later than 2:00
p.m., New York City time, on the fifth (5th) Business Day preceding the date on
which such Advance is to be made. Such notice shall specify (A) the amount of
the proposed Advance and (B) the date thereof (which shall be a Business Day).

            (d) Each Advance requested by Genta shall be as specified on the
applicable Borrowing Certificate delivered to Aventis in connection with such
Advance and shall be in a minimum amount of $5,000,000 (or such lesser amount as
shall equal the available but unused Commitment).

            (e) All outstanding Advances shall be payable in full on the
Maturity Date, subject to mandatory prepayment as provided in Section 19.3
hereof and acceleration as provided in Article 19.8 hereof.

            (f) From and after the Commitment Termination Date all payments
otherwise due to Genta from Aventis, including without limitation, any milestone
payments due under Section 6.2, shall be retained by Aventis and applied against
any outstanding Advances until repaid in full unless Genta provides cash
collateral in an amount equal to the outstanding Advances or other substitute
collateral which Aventis determines at such time in its sole discretion to be
satisfactory.

            (g) Within five (5) Business Days from the beginning of each
calendar month, Genta shall provide to Aventis the amount of accrued Development
Costs owing from Aventis to Genta, together with such documentation as
reasonably requested by Aventis in order to verify such Development Costs (the
"Development Cost Report"). Aventis acknowledges that such documentation may not
include all information customarily submitted by Genta with its quarterly
invoices. Within two (2) Business Days following receipt of the Development Cost
Report, Aventis shall determine the Borrowing Base in its reasonable good faith
discretion and provide Genta written notification thereof, together with a
report indicating how the Borrowing Base was calculated (the "Borrowing Base
Report"). Following the determination of the Borrowing Base


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<PAGE>

for any particular month, upon any changes to the applicable Over Advance Amount
as determined by Aventis in its reasonable good faith discretion, Aventis shall
provide to Genta a revised Borrowing Base Report reflecting a revised Borrowing
Base, and such revised Borrowing Base shall thereafter be the Borrowing Base
until subsequently revised as set forth herein or until a Borrowing Base is
determined for the next succeeding month. Based on receiving cooperation from
Genta, Aventis shall use good faith efforts to determine the Borrowing Base for
March 2003 by March 20, 2003.

            SECTION 19.2 Interest.

            (a) Interest shall accrue at a rate per annum (computed on the basis
of the actual number of days elapsed over a year of 360 days) equal to (*) per
annum, compounded quarterly, and shall be due and payable in one lump sum on the
Maturity Date.

            (b) Interest in respect of any Advance hereunder shall accrue from
and including the date of such Advance to but excluding the date on which such
Advance is paid, such that interest on any Advance which is prepaid in part or
in full in accordance with Section 19.3 hereof shall cease to accrue as it
relates to such part of the Advance as was prepaid on the date on which such
prepayment is made; provided, however, that interest shall continue to accrue on
(i) any portion of the Advance that was not prepaid and (ii) the balance of any
accrued but unpaid interest related to such prepaid Advance.

            (c) Anything in this Agreement to the contrary notwithstanding, the
interest rate on the Advances shall in no event be in excess of the maximum
permitted by Applicable Law.

            SECTION 19.3 Prepayments.

            (a) Genta shall have the right at its option at any time and from
time to time to prepay any Advance, in each case in whole or in part, upon at
least three (3) Business Days' prior written, telecopier or telephonic (promptly
confirmed in writing) notice to Aventis; provided, however, that, if Genta
elects to prepay any Advance in part, each such partial prepayment shall be in
the minimum amount of $1,000,000, or in the amount of the outstanding principal
amount of Advances made to Genta, together with all accrued and unpaid interest
thereon. Each notice of prepayment shall specify the prepayment date, and the
principal amount thereof, shall be irrevocable and shall commit Genta to prepay
Advances in the amount and on the date stated therein.

            (b) If at any time the aggregate principal amount of the Advances
outstanding together with all accrued and unpaid interest thereon shall exceed
the Maximum Advance, (i) Genta shall prepay Advances within 30 days to the
extent necessary to eliminate such excess and (ii) all payments otherwise due to
Genta from Aventis hereunder may, at Aventis' sole discretion, be retained by
Aventis and applied against the outstanding Advances until the aggregate
principal amount of the Advances outstanding , together with all accrued and
unpaid interest thereon are less than the Maximum Advance.


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<PAGE>

            SECTION 19.4 Default Interest.

            So long as an Advance Default shall have occurred and be continuing
(after, as well as before judgement), any amounts due hereunder, including
without limitation, any unpaid Advances or any accrued and unpaid interest
thereon, shall thereafter bear interest and be payable on demand at a rate equal
to the (*) per annum, compounded quarterly.

            SECTION 19.5 Manner of Payments.

            All payments by Genta hereunder shall be made without offset or
counterclaim in Dollars in Federal or other immediately available funds to such
account as Aventis may designate in writing, no later than 12:00 noon, New York
City time, on the date on which such payment shall be due. Any payment received
at such office after such time shall be deemed received on the following
Business Day. All payments on account of the Advances shall be applied first to
payment of all fees and expenses, including collection costs, due to Aventis
hereunder or under the Security Agreement, next toward payment of interest due
on the unpaid principal balance hereof, and the remainder, if any, to the
principal due hereunder.

            SECTION 19.6 Conditions Precedent to Each Advance.

            The obligation of Aventis to make each Advance is subject to the
following conditions precedent:

            (a) Notice. Aventis shall have received a notice with respect to
such borrowing as required by Section 19.1 hereof.

            (b) Representations and Warranties. The representations and
warranties set forth in Article 17 hereof and in the Security Agreement (each as
supplemented or qualified on or prior to the date by written information
communicated by Genta to Aventis) shall be true and correct in all material
respects on and as of the date of each borrowing hereunder (except to the extent
that such representations and warranties expressly relate to an earlier date)
with the same effect as if made on and as of such date.

            (c) No Advance Default. On the date of the making of each Advance
hereunder, Genta shall be in compliance with all of the terms and provisions set
forth herein and in the Security Agreement on their part to be observed or
performed, and no Advance Default shall have occurred and be continuing, nor
shall any Advance Default occur by reason of the making of such Advance.

            (d) Borrowing Certificate. On the date of the making of each Advance
hereunder, Aventis shall have received a borrowing certificate, substantially in
the form of Exhibit B to the First Amendment to the U.S. Commercialization
Agreement, executed by those Persons contemplated by such Exhibit B. Any such
certificate shall be referred to herein as a "Borrowing Certificate".


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<PAGE>

            (e) Additional Documents. Aventis shall have received from Genta on
the date of each borrowing such documents and information as it may reasonably
request relating to the satisfaction of the conditions in this Section 19.6.

Each borrowing shall be deemed to be a representation and warranty by Genta on
the date of such borrowing as to the matters specified in paragraphs (b) and (c)
of this Section 19.6.

            SECTION 19.7 Covenants of Genta Relating to the Advance.

            Genta covenants and agrees that until payment in full of the
principal of and interest on the Advances, it will:

            (a) Do or cause to be done all things necessary to preserve, renew
and keep in full force and effect its corporate existence, rights, licenses,
permits and franchises, and comply with all applicable statutes, regulations and
orders of, and all applicable restrictions imposed by, any Governmental
Authority, except to the extent that any such failure to act or comply would not
result in a material adverse effect on Genta's property, assets, liabilities,
business or operations. Notwithstanding the foregoing, nothing contained in this
Section 19.7(a) shall limit or otherwise modify any other covenants or
agreements of Genta set forth in any other provisions in this Agreement;

            (b) At least 30 days before the beginning of each Calendar Quarter,
deliver to Aventis a report showing in reasonable detail Genta's expected
Development Costs next two Calendar Quarters which report shall be in a form
reasonably acceptable to Aventis;

            (c) Within 5 Business Days after the beginning of each calendar
month, deliver to Aventis the Development Cost Report.

            (d) Not incur, create, assume or suffer to exist any lien on the
Collateral except for Permitted Liens (as such term is defined in the Security
Agreement); and

            (d) Not change its state of incorporation unless (i) it provides
Aventis 45 days' prior written notice of its intention to do so and provides
Aventis with any other information in connection therewith as Aventis may
request and (ii) it shall have taken all actions reasonably requested by Aventis
to maintain the security interests granted to Aventis under the Security
Agreement.

            SECTION 19.8 Advance Default.

            In the case of the happening and during the continuance of any of
the following events (herein called "Advance Default"):

            (a) Genta shall have materially breached any of its representations
or warranties hereunder, under the Security Agreement, under the Ex-U.S.
Commercialization Agreement or under the Global Supply Agreement;


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<PAGE>

            (b) Genta shall have materially breached or defaulted in the
performance of any of its covenants or agreements hereunder, under the Security
Agreement, under the Ex-U.S. Commercialization Agreement or under the Global
Supply Agreement;

            (c) default shall be made in the payment of principal of the
Advances or of interest on the Advances as and when due and payable;

            (d) default in payment shall be made with respect to any
indebtedness of Genta in excess of (*), when due, or in the performance of any
other obligation incurred in connection with any indebtedness of Genta in excess
of (*), if the effect of such default is to accelerate the maturity of such
indebtedness, and such default shall not be remedied, cured, waived or consented
to within the period of grace with respect thereto. For purposes of this Section
19.8(d), the term "indebtedness" shall mean: (i) all obligations for borrowed
money, (ii) all amounts evidenced by bonds, debentures, notes or other similar
instruments, (iii) all obligations to pay the deferred purchase price of goods,
property or services, including trade payables (except to the extent any amount
owing in connection with a trade payable is being diligently contested in good
faith and reasonable reserves related thereto have been established), (iv) all
obligations secured by a lien on assets, (v) capital lease obligations, or (vi)
all other indebtedness which would be included as a liability in a balance sheet
in accordance with generally accepted accounting principles;

            (e) Genta shall generally not pay its debts as they become due or
shall admit in writing its inability to pay its debts, or shall make a general
assignment for the benefit of creditors; or Genta shall commence any case,
proceeding or other action seeking to have an order for relief entered on its
behalf as debtor or to adjudicate it a bankrupt or insolvent or seeking
reorganization, arrangement, adjustment, liquidation, dissolution or composition
of it or its debts under any law relating to bankruptcy, insolvency,
reorganization or relief of debtors or seeking appointment of a receiver,
trustee, custodian or other similar official for it or for all or any
substantial part of its property or shall file an answer or other pleading in
any such case, proceeding or other action admitting the material allegations of
any petition, complaint or similar pleading filed against it or consenting to
the relief sought therein; or Genta shall take any action to authorize or in
contemplation of any of the foregoing;

            (f) any involuntary case, proceeding or other action against Genta
shall be commenced seeking to have an order for relief entered against it as
debtor or to adjudicate it a bankrupt or insolvent, or seeking reorganization,
arrangement, adjustment, liquidation, dissolution or composition of it or its
debts under any law relating to bankruptcy, insolvency, reorganization or relief
of debtors, or seeking appointment of a receiver, trustee, custodian or other
similar official for it or for all or any substantial part of its property, and
such case, proceeding or other action (i) results in the entry of any order for
relief against it or (ii) shall remain undismissed for a period of sixty (60)
days;

            (g) final judgment(s) for the payment of money in excess of (*)
(which judgment(s) is not covered by insurance) shall be rendered against Genta
and within sixty (60) days from the entry of such judgment shall not have been
discharged or stayed pending appeal or


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<PAGE>

shall not have been discharged within sixty (60) days from the entry of a final
order of affirmance on appeal;

            (h) (*) or

            (j) Genta shall have repudiated its obligations thereunder;

then, in every such event and at any time thereafter during the continuance of
such event, Aventis may take either or both of the following actions, at the
same or different times: terminate forthwith the Commitment and/or declare the
principal of and the interest on the Advances and all other amounts payable
hereunder to be forthwith due and payable, whereupon the same shall become and
be forthwith due and payable, without presentment, demand, protest, or other
notice of any kind, all of which are hereby expressly waived, anything in this
Agreement to the contrary notwithstanding; provided that with respect to any
event referenced in Section 19.8(b) above that by its nature is capable of cure,
Genta shall have 30 days to cure such event after delivery of written notice by
Aventis of such event, and until such 30 days have elapsed such event shall not
constitute an Advance Default. Such remedies shall be in addition to any other
remedy available to Aventis pursuant to Applicable Law or otherwise.

            SECTION 19.9 Additional Remedies Upon An Advance Default.

            Notwithstanding anything to the contrary in the Global Supply
Agreement, upon the occurrence of an Advance Default, in addition to the other
remedies herein set forth or available to Aventis pursuant to Applicable Law or
otherwise, Aventis may, in its sole discretion, issue a firm purchase order for
Finished Product, Bulk Drug Product and/or API (as each such term is defined in
the Global Supply Agreement) in a quantity equal to the lesser of (i) the amount
of inventory of Finished Product, Bulk Drug Product or API, as applicable, owned
by Genta and (ii) the quantity valued at an amount equal to any outstanding
Advances hereunder plus any accrued and unpaid interest; provided that such
Finished Product, Bulk Drug Product and/or API shall be valued for purposes
hereof in accordance with the terms of the Global Supply Agreement and shall be
deemed to satisfy any such Advance (plus interest) with respect to such value.

            Section 3. Conditions to Effectiveness. The effectiveness of this
Amendment is subject to the satisfaction of all of the following conditions
precedent (the date on which all such conditions have been satisfied being
herein called the "Effective Date"):

                  (a) Aventis shall have received with respect to Genta:

                        (i) a copy of Genta's certificate of incorporation,
            certified as of a recent date by the Secretary of State of Delaware;

                        (ii) a certificate of the Secretary of State of
            Delaware, dated as of a recent date as to the good standing of, and
            payment of taxes by, Genta, which certificate lists the charter
            documents on file in the office of such Secretary of State;


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<PAGE>

                        (iii) a certificate dated as of a recent date as to the
            good standing of Genta, issued by the Secretary of State of each
            jurisdiction in which Genta is qualified as a foreign corporation;

                        (iv) a certificate of the Secretary of Genta dated the
            date of the initial Advance and certifying (A) that attached thereto
            is a true and complete copy of the By-Laws of Genta as in effect on
            the date of such certification, (B) that attached thereto is a true
            and complete copy of resolutions duly adopted by the Board of
            Directors of Genta authorizing the borrowings hereunder and the
            execution, delivery and performance in accordance with their terms
            of this U.S. Commercialization Agreement and the Security Agreement
            and any other documents required or contemplated hereunder or
            thereunder to which Genta is a party, (C) that attached thereto is a
            true and complete copy of the Certificate of Incorporation of Genta
            and that the Certificate of Incorporation of Genta has not been
            amended since the date of the last amendment thereto indicated on
            the certificate of the Secretary of State furnished pursuant to
            clause (i) above except to the extent specified in such Secretary's
            Certificate and (D) as to the incumbency and specimen signature of
            each officer of Genta executing this U.S. Commercialization
            Agreement and the Security Agreement or any other document delivered
            by Genta in connection herewith or therewith (such certificate to
            contain a certification by another officer of Genta as to the
            incumbency and signature of the officer signing the certificate
            referred to in this clause (iv));

                        (v) such additional supporting documents as Aventis or
            its counsel may reasonably request;

            (b) Aventis shall have received a fully executed Security Agreement;

            (c) Aventis shall have received the favorable written opinion, dated
the date of the first Advance hereunder, addressed to Aventis of Wilson Sonsini
Goodrich & Rosati, PC, counsel to Genta, in form and substance satisfactory to
Aventis; and

            (d) the receipt by Aventis of counterparts of this Amendment which,
when taken together, bear the signatures of Aventis and Genta.

            Section 4. Representations and Warranties. Genta represents and
warrants that:

            (a) after giving effect to this Amendment, the representations and
warranties contained in the U.S. Commercialization Agreement are true and
correct in all material respects on and as of the date hereof as if such
representations and warranties had been made on and as of the date hereof
(except to the extent that any such representations and warranties specifically
relate to an earlier date); and

            (b) after giving effect to this Amendment, no Advance Default will
have occurred and be continuing on and as of the date hereof.


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<PAGE>

            Section 5. Further Assurances. At any time and from time to time,
upon Aventis's request and at the sole expense of Genta, Genta will promptly and
duly execute and deliver any and all further instruments and documents and take
such further action as Aventis reasonably deems necessary to effect the purposes
of this Amendment.

            Section 6. Full Force and Effect. Except as expressly amended
hereby, the U.S. Commercialization Agreement shall continue in full force and
effect in accordance with the provisions thereof on the date hereof. As used in
the U.S. Commercialization Agreement, the terms "Agreement", "this Agreement",
"herein", "hereafter", "hereto", "hereof", and words of similar import, shall,
unless the context otherwise requires, mean the U.S. Commercialization Agreement
as amended by this Amendment.

            Section 7. APPLICABLE LAW. THIS AMENDMENT SHALL BE GOVERNED BY AND
CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

            Section 8. Counterparts. This Amendment may be executed in two or
more counterparts, each of which shall constitute an original, but all of which
when taken together shall constitute but one instrument.

            Section 9. Headings. The headings of this Amendment are for the
purposes of reference only and shall not affect the construction of or be taken
into consideration in interpreting this Amendment.


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<PAGE>

            IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
be duly executed as of the day and the year first written.

                                                GENTA INCORPORATED

                                                By______________________________
                                                    Name:
                                                    Title:


                                                AVENTIS PHARMACEUTICALS INC.

                                                By______________________________
                                                    Name:
                                                    Title:


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<PAGE>

                                   Exhibit A

                               Security Agreement

<PAGE>

                                    Exhibit B

                              Borrowing Certificate

<PAGE>

                          FORM OF BORROWING CERTIFICATE

      The undersigned HEREBY CERTIFIES with respect to the Advances to be made
on the date indicated below pursuant to the U.S. Commercialization Agreement
dated as of April 26, 2002 between Genta Incorporated ("Genta") and Aventis
Pharmaceuticals Inc. ("Aventis") as amended by Amendment No. 1 dated as of March
14, 2003 (as the same may be further amended, supplemented or otherwise
modified, the "U.S. Commercialization Agreement; capitalized terms used herein
and not otherwise defined shall have the meanings set forth in the U.S.
Commercialization Agreement) that:

            (a) the representations and warranties contained in Article 17 of
      the U.S. Commercialization Agreement and in the Security Agreement (each
      as supplemented or qualified on or prior to the date hereof by written
      information communicated by Genta to Aventis) are true and correct in all
      material respects on and as of the date hereof as if such representations
      and warranties had been made on and as of the date hereof (except to the
      extent that such representations and warranties expressly relate to an
      earlier date) with the same effect as if made on and as of such date;

            (b) no default or Advance Default has occurred or is continuing, nor
      shall any such default or Advance Default occur by reason of the making of
      the Advance requested herein;

            (c) Genta requests an Advance on the terms and conditions as stated
      in the U.S. Commercialization Agreement:

                  (i) the requested Business Day of the Advance is ____________;

                  (ii) the amount of the requested Advance is $________________;

            (d) The undersigned has no reason to believe that the lesser of the
      Borrowing Base if currently computed and the Commitment would be less than
      the sum of the outstanding principal amount of all Advances plus all
      accrued interest thereon owed by Genta to Aventis under the U.S.
      Commercialization Agreement (after giving effect to the Advance requested
      hereby).

      IN WITNESS WHEREOF, the undersigned has caused this certificate to be
executed this ____ day of ________, _____.

                                                  GENTA INCORPORATED.


                                                  By____________________________
                                                    Name:
                                                    Title: