<PAGE>

                          COMMON STOCK PURCHASE AGREEMENT


     This Common Stock Purchase Agreement ("Agreement") is made and entered into
as of June 11, 1998 by and between THE IMMUNE RESPONSE CORPORATION., a Delaware
corporation (hereinafter referred to as the Company) and AGOURON
PHARMACEUTICALS, INC., a California corporation ("Agouron"), which parties
hereby agree as follows:

1.   AUTHORIZATION; COMMITMENT; CLOSING

     1.01      AUTHORIZATION.  The Company proposes to authorize, issue and sell
to Agouron on or before January 15, 2000, certain amounts of its common stock,
$.0025 par value ("Common Stock"), as described and determined below.

     1.02 COMMITMENT.  Subject to Paragraph 5.06 and the terms and conditions
hereof and on the basis of the representations and warranties hereinafter set
forth, the Company agrees to issue and sell to Agouron, and Agouron agree to
purchase from the Company as of the dates and for the consideration set forth
below, the number of shares of the Company's Common Stock as determined below. 
The Common Stock which Agouron is acquiring pursuant to the terms of this
Agreement is hereinafter referred to as "Restricted Common Stock".  Agouron is
hereinafter sometimes referred to as the "Purchaser."  The purchases of the
Common Stock shall occur on the seven purchase dates set forth below.  On each
purchase date, Agouron shall be entitled to acquire such number of shares of
Restricted Common Stock (rounded up to the nearest whole share) as may be
purchased for $2,000,000, at a purchase price equal to the stated premium set
forth opposite the applicable purchase date, over the then fair market value
("FMV") of the Common Stock on The NASDAQ Stock Market.  FMV shall be defined as
the average closing price of the Common Stock on The NASDAQ Stock Market for the
five (5) trading days immediately preceding the referenced purchase date.  In
the event the FMV is "***" on any purchase date, the premium applicable to such
purchase date shall be adjusted to "***."

<TABLE>
<CAPTION>

Purchase Date          Purchase Price                Premium Over FMV
-------------          --------------                ----------------
<S>                    <C>                           <C>
June 11, 1998            $2,000,000                          50%
October 15, 1998         $2,000,000                          ***
January 15, 1999         $2,000,000                          ***
April 15, 1999           $2,000,000                          ***
July 15, 1999            $2,000,000                          ***
October 15, 1999         $2,000,000                          ***
January 15, 2000         $2,000,000                          ***
</TABLE>

     1.03      CLOSING.  Separate closings of the purchase and sale of the
Restricted Common Stock ("Closings") shall occur on each of the purchase dates
set forth above and shall take place at such time and place as the Company and
Purchaser shall agree.  At each Closing the Company shall deliver to Purchaser
the number of shares of Restricted Common Stock required by Paragraph 1.02,
above, upon delivery to the 


*** - Confidential treatment requested.  Sections of text which have been
omitted and for which confidential treatment is requested are noted with "***". 
An unredacted version of this document has been filed separately with the
Securities and Exchange Commission.


<PAGE>

Company by Purchaser of a certified check or wire transfer of funds in the
amount of $2,000,000.  The Restricted Common Stock to be delivered to Agouron
hereunder at each Closing will be evidenced by a single certificate registered
in Agouron's name or in the name of such nominee as Agouron may specify and,
when issued in accordance with the terms of this Agreement for the consideration
expressed herein, will be duly authorized, validly issued, fully paid,
nonassessable and free and clear of any liens or encumbrances caused or created
by the Company (except that such Restricted Common Stock of the Company will be
subject to restrictions on transfer under federal and applicable state
securities laws).

2.   REPRESENTATIONS

     2.01  REPRESENTATIONS OF THE COMPANY.  The Company represents and
warrants as follows:

           (a)  The Company is a corporation duly organized, validly
           existing and in good standing under the laws of the State of
           Delaware and has all requisite power and authority which are
           necessary to own and operate its business and properties and to
           carry on its business as it is being conducted.  The Company is
           duly licensed and qualified and in good standing in the State of
           California and in such other jurisdictions in which the ownership
           or lease of property or the conduct of its business makes such
           licensing or qualification necessary.
               
           (b)  There are no proceedings pending or, to the knowledge of the
           Company, threatened against or affecting the Company in any court
           or before any governmental authority or agency or arbitration
           board or tribunal which involve the possibility of materially and
           adversely affecting the properties, business, prospects or
           condition (financial or otherwise) of the Company.
           
           (c)  The issuance and sale of the Restricted Common Stock and
           compliance by the Company with all of the provisions of this
           Agreement are within the corporate powers of the Company and have
           been duly authorized by all proper corporate action on the part
           of the Company and will not (i) conflict with or result in any
           breach of any of the terms, conditions or provisions of, or
           constitute a default under the Articles of Incorporation of the
           Company or the Bylaws of the Company, (ii) conflict with or
           result in any breach of any of the terms, conditions or
           provisions of, or constitute a default under or give any party
           the right to terminate or accelerate performance under any other
           agreement or instrument to which the Company is a party (iii)
           require consent under any other contract to which the Company is
           a party, (iv) result in the creation or imposition of any lien,
           charge or encumbrance upon any property or assets of the Company
           pursuant to the terms of any other contract to which the Company
           is a party or (v) conflict with any provision of any applicable
           judgment, decree, order, statute, rule, or regulation of any
           court or any public, governmental or regulatory agency or body
           having jurisdiction over the Company.


                                     2


<PAGE>

           (d)  This Agreement is a valid and binding agreement of the
           Company and is enforceable against the Company in accordance with
           the terms hereof, except as such enforceability may be affected
           by applicable bankruptcy laws and equitable remedies.
               
           (e)  The authorized capital stock of the Company consists of
           5,000,000 shares of preferred stock (preferred stock) and
           40,000,000 shares of common stock.  As of the date hereof, 200
           shares of its Series F Convertible Preferred Stock are
           outstanding.  This preferred stock is convertible into common
           stock initially at a conversion price equivalent to $14.07 per
           share of common stock.  If the Company's common stock does not
           trade at prices higher than $14.07 per share over a period of
           time, the conversion price will be adjusted downward on April 24,
           1999 (or sooner if the Company issues common stock at less than
           $14.07 per share) and quarterly thereafter.  As of June 9, 1998,
           22,900,350 shares of voting common stock are outstanding.  As of
           the date hereof, 4,497,749 stock options issued pursuant to the
           Company's stock option plans and two (2) warrants to purchase a
           total of 2,051,281 shares of voting stock are outstanding.  Up to
           6,180,000 shares of common stock may be issued under the
           Company's stock option plans.  Except as set forth above, there
           are no other options, warrants, conversion privileges, preemptive
           rights, or  rights of first refusal granted by the Company in
           favor of any other person presently outstanding or in existence
           to purchase or acquire any of the authorized but unissued Common
           Stock of the Company, other than any of such items granted
           pursuant to this Agreement.  The Company has provided to
           Purchaser copies of its currently in effect Articles of
           Incorporation and Bylaws, its Form 10-K for the year ended
           December 31, 1997, its 1997 Annual Report, its Proxy statement
           dated April 27, 1998 and its Form 10-Q for the quarter ended
           March 31, 1998. The Company warrants that the information
           contained in such documents as updated and supplemented prior to
           the date of the Closing is true and correct and when taken as a
           whole does not omit a fact necessary to make the information
           contained therein in light of the circumstance under which the
           documents were made (taking into account, without limitation, the
           type of transaction contemplated by this Agreement and the
           sophistication and nature of the Purchaser), not misleading.  The
           Company acknowledges that the Purchaser is relying on the written
           documentation provided by the Company to Purchaser as described
           above in making its decision to purchase the Restricted Common
           Stock.
           
           (f)  Since March 31, 1998, except for the sale of 200 shares of
           Series F Convertible Preferred Stock for $10 million, there has
           not been any change in the assets, liabilities, financial
           condition or operations of the Company other than changes in the
           ordinary course of business, none of which individually or in the
           aggregate have had a material adverse affect on such assets,
           liabilities, financial condition or operations of the Company.
           

                                     3


<PAGE>

     2.02  REPRESENTATIONS OF THE PURCHASER.  The Purchaser represents and
warrants as follows:

     (a)  It is the intent of the Purchaser that its purchase of the
     Restricted Common Stock contemplated by this Agreement shall constitute a
     transaction exempt from registration under the Securities Act of 1933, as
     amended (the "Securities Act") and any applicable state securities laws.
     
     (b)  Purchaser will not offer or sell any Restricted Common Stock
     except pursuant to an effective registration statement under the Securities
     Act or in transactions which do not require registration under the
     Securities Act.
     
     (c)  Purchaser is a corporation duly organized and validly existing
     under the laws of the State of California is in good standing under such
     laws and has all requisite corporate powers and authority to enter into
     this Agreement.
     
     (d)  On or prior to the date of the initial Closing, Purchaser will
     have taken all action necessary for the authorization, execution, delivery
     and performance of this Agreement.
     
     (e)  Purchaser has (i) reviewed this Agreement, and the written
     statements, and documents, delivered to Purchaser as described in Section
     2.01(e); and, (ii) received satisfactory response from the Company as to
     matters about which Purchaser has inquired relating to this Agreement, and
     other documents described in Section 2.01(e) and relating to the Company's
     business condition, prospects and plans as necessary to evaluate the merits
     and risks of acquiring the Restricted Common Stock.  Purchaser has informed
     the Company that Purchaser is relying on all such information and documents
     in making its decision to purchase the Restricted Common Stock.
     
     (f)  Purchaser (i) has had the risks involved in the investment
     represented by this Agreement explained; (ii) has knowledge and experience
     in financial and business matters to evaluate the merits and risks of the
     investment represented by this Agreement; (iii) is able to bear the
     economic risk of the investment represented by this Agreement (including a
     complete loss of this investment); and (iv) has determined that this
     investment is suitable for Purchaser in light of Purchaser's financial
     circumstances and available investment opportunities.
     
     (g)  Purchaser is acquiring the Restricted Common Stock for its own
     account and with its general assets for the purpose of investment and not
     with a view to the resale, transfer or distribution thereof, and has no
     present intention of selling, transferring, negotiating or otherwise
     disposing of any Restricted Common Stock.  Notwithstanding anything in this
     Agreement to the contrary, it is agreed that the Purchaser shall have the
     right to assign or transfer the Restricted Common Stock to its Affiliates
     at any time without the consent of the Company.


                                     4


<PAGE>


3.   NON-DISCLOSURE.  Except as agreed to by the parties neither the Company nor
the Purchaser shall release any information to any third party with respect to
any of the terms of this Agreement without the prior written consent of the
other, which consent shall not unreasonably be withheld.  This prohibition
includes, but is not limited to, press releases, promotional materials and
discussions with the media.  If the Company determines that it is required by
law to release information to any third party regarding the terms of this
Agreement, it shall notify the Purchaser of this fact prior to releasing the
information.  The notice to the Purchaser shall include the text of the
information proposed for release.  The Purchaser shall have the right to confer
with the Company regarding the necessity for the disclosure and the text of the
information proposed for release.

4.   COMPLIANCE WITH SECURITIES ACT

     4.01  CERTAIN DEFINITIONS.  As used herein, the following terms shall
have the following respective meanings:

     (a)   COMMISSION.  Shall mean the Securities and Exchange Commission,
     or any other Federal agency at the time administering the Securities Act or
     the Trust Indenture Act, as the case may be.
     
     (b)   SECURITIES ACT.  Shall mean the Securities Act of 1933, as
     amended, or any similar Federal statute, and the rules and regulations of
     the Commission thereunder, all as the same shall be in effect at the
     relevant time.
     
     (c)   EXCHANGE ACT.  Shall mean the Securities Exchange Act of 1934, as
     amended, or any similar Federal statute, and the rules and regulations of
     the Commission thereunder, all as the same shall be in effect at the
     relevant time.
     
     (d)   RESTRICTED COMMON STOCK.  Shall mean the Common Stock of the
     Company issued and sold pursuant to this Agreement which by the terms
     hereof is required to bear the legend specified in Section 4.02 hereof.
                    
     4.02  RESTRICTION OF TRANSFERABILITY; LEGEND.  Shares of Restricted
Common Stock shall not be resold or transferred unless registered under the
Securities Act or unless an exemption from registration is available for such
sale or transfer.  The conditions specified below are intended to ensure
compliance with the provisions of the Securities Act in respect of any transfer
of stock.  Each certificate for shares of Restricted Common Stock shall be
stamped or otherwise imprinted with a legend in substantially the following
form:

                The shares evidenced by this certificate have not been
                registered under the Securities Act of 1933, as
                amended, and may not be sold or transferred in the
                absence of such registration or an exemption therefrom
                under said Securities Act and the transfer of such


                                     5


<PAGE>

                shares is subject to terms and conditions specified in
                the Common Stock Purchase Agreement dated as of June
                11, 1998, between the Company and Agouron
                Pharmaceuticals, Inc.
                    
If shares of Restricted Common Stock evidenced by certificates bearing a legend
required by this Section 4.02 are sold in accordance with a registration
statement which has become effective under the Securities Act, or if the Company
shall receive an opinion of its counsel to the effect that any legend required
under this Section 4.02 is not, or is no longer, necessary or required with
respect to such shares (including, without limitation, because of the
availability of the exemption afforded by Rule 144 of the General Rules and
Regulations of the Commission), the Company shall, or shall instruct its
transfer agent and registrar to, remove such legend or issue new certificates
without such legend in lieu thereof.

     4.03  INFORMATION REQUIREMENTS.  The Company agrees to:

           (a)   Make and keep public information available, as such term is
           understood and defined in Commission Rule 144 and Rule 144A, under 
           the Securities Act;
     
           (b)   Use its best efforts to file with the Commission in a timely
           manner all reports and other documents required of the Company 
           under the Securities Act and the Exchange Act; and
     
           (c)   Furnish to any holder of Restricted Common Stock a copy of the
           most recent annual or quarterly report of the Company, and such other
           publicly available reports and documents of the Company, so that such
           holder may avail itself of any rule or regulation of the Commission
           allowing it to sell any such securities without registration.

     4.04  PIGGY-BACK REGISTRATION RIGHTS.  If the Company before January
15, 2001 contemplates a public offering of shares of its Common Stock to be
registered under the Securities Act, the Company shall so notify the Purchaser
in writing of its intention to do so, at least twenty (20) days prior to the
filing of a registration statement for such offering.  If Purchaser gives
written notice to the Company, within ten (10) days of receipt of the notice
from the Company, of Purchaser's desire to have its Restricted Common Stock
included in such registration statement,  Purchaser may, subject to the
provisions of this Section 4.04, have its Restricted Common Stock included in
such registration statement.  The Company shall bear all expenses in connection
with the registration and sale of any such Restricted Common Stock, other than
the fees or disbursements of any special counsel which the Purchaser may retain
in connection with the registration of its Restricted Common Stock or any
portion of the underwriter's commission, discounts and expenses attributable to
the Restricted Common Stock being offered and sold by the Purchaser. 
Notwithstanding the foregoing, if the managing underwriter of any such offering
determines that the number of shares proposed to be sold by the Company, by
other shareholders having piggy-back rights, and/or by the Purchaser is greater
than the number of shares which the underwriter believes feasible to sell at the
time, at the price and upon the terms approved by the Company, then the 


                                     6


<PAGE>


number of shares which the underwriter believes may be sold shall be 
allocated for inclusion in the registration statement in the following order 
of priority:  (i) shares being offered by the Company; and (ii) pro rata 
among the other shareholders and the Purchaser, based on the number of shares 
of Common Stock each shareholder requested to be registered.  The Company 
shall have the right to designate the managing underwriter in respect of a 
public offering pursuant to this Section 4.04.

     4.05  ADDITIONAL COVENANTS CONCERNING SALE OF SHARES.

          (a)   The Company will notify the Purchaser of the effectiveness of 
          any registration statement in which Purchaser has exercised 
          registration rights granted pursuant to the terms of Section 4.04,
          together with a list of the jurisdictions where the Company has 
          qualified or is exempt from registration under applicable state
          securities laws.
               
          (b)   The Company will prepare and file with the Commission such
          amendments and supplements to any registration statement filed 
          pursuant to the terms of Section 4.04 (and any prospectus used in 
          connection with such registration statement) as may be necessary to 
          comply with the provisions of the Securities Act with respect to the 
          sale of Restricted Common Stock by the Purchaser.
               
          (c)   The Company will furnish to the Purchaser a reasonable number 
          of copies of the prospectus used in connection with a registration 
          statement filed pursuant to the terms of Section 4.04, including a 
          preliminary prospectus, which prospectus conforms to the requirements
          of the Securities Act, and such other documents as the Purchaser may 
          reasonably request, in order to facilitate the disposition of the 
          Purchaser's Restricted Common Stock.
               
          (d)   In connection with any registration statement referred to in
          Section 4.04 of this Agreement,  Purchaser will furnish to the 
          Company such information as the Company may reasonably require 
          from Purchaser for inclusion in the registration statement (and 
          the prospectus included therein).
               
          (e)   The Company's obligations under Section 4.04 shall be 
          conditioned upon Purchaser executing and delivering to the 
          Company its agreement, in a form satisfactory to counsel for 
          the Company, that it will comply with all applicable provisions
          of the Securities Act, the Exchange Act, the securities acts
          of applicable states and any rules and regulations promulgated
          under such acts and will furnish to the Company information
          about sales made in such public offering.

     4.06  INDEMNIFICATION

     In the event any of the Restricted Common Stock of Purchaser is included in
a registration statement under Section 4.04 of this Agreement:


                                     7


<PAGE>

     (a)  To the extent permitted by law, the Company will indemnify and
     hold harmless the Purchaser and its Affiliates and their respective
     officers, directors and employees, against any losses, claims, damages, or
     liabilities (joint or several) to which they may become subject under the
     Securities Act, the Exchange Act or other federal or state law, insofar as
     such losses, claims, damages, or liabilities (or actions in respect
     thereof) arise out of or are based upon any of the following statements,
     omissions or violations (hereinafter sometimes collectively referred to as
     a "Violation(s)"):  (i) any untrue statement or alleged untrue statement of
     a material fact contained in such registration statement, including any
     preliminary prospectus or final prospectus contained therein or any
     amendments or supplements thereto; (ii) the omission or alleged omission to
     state therein a material fact required to be stated therein, or necessary
     to make the statements therein not misleading; or (iii) any violation or
     alleged violation by the Company of the Securities Act, the Exchange Act,
     any state securities law or any rule or regulation promulgated under the
     Securities Act, the Exchange Act or any state securities law; and the
     Company will reimburse each such indemnified party for any legal or other
     expenses reasonably incurred by it in connection with investigating or
     defending any such loss, claim, damage, liability or action; provided,
     however, that the indemnity agreement contained in this Section 4.06 shall
     not apply to amounts paid in settlement of any such loss, claim, damage,
     liability or action if such settlement is effected without the consent of
     the Company (which consent shall not be unreasonably withheld or delayed),
     nor shall the Company be liable in any such case for any such loss, claim,
     damage, liability or action to the extent that it arises out of or is based
     upon a Violation which occurs in reliance upon, and in conformity with,
     written information furnished expressly for use in connection with such
     registration, by any such indemnified party.

     (b)  To the extent permitted by law, the Purchaser will indemnify and
     hold harmless the Company and its Affiliates and their respective officers,
     directors and employees against any losses, claims, damages, or liabilities
     (joint or several) to which they may become subject under the Securities
     Act, the Exchange Act or other federal or state law, insofar as such
     losses, claims, damages, or liabilities (or actions in respect thereof)
     arise out of or are based upon any Violations, in each case to the extent
     (and only to the extent) that such Violation occurs in reliance upon, and
     in conformity with, written information furnished by the Purchaser and its
     Affiliates and their respective officers, directors and employees to the
     Company expressly for use in connection with such registration; and the
     Purchaser will reimburse each such indemnified party for any legal or other
     expenses reasonably incurred by it in connection with investigating or
     defending any such loss, claim, damage, liability or action; provided,
     however, that the indemnity agreement contained in this Section 4.06 shall
     not apply to amounts paid in settlement of any such loss, claim, damage,
     liability or action if such settlement is effected without the consent of
     the Purchaser, which consent shall not be unreasonably withheld or delayed.


                                     8


<PAGE>

     (c)  Promptly after receipt by an indemnified party under this Section
     4.06 of notice of the commencement of any action (including any
     governmental action), such indemnified party will, if a claim in respect
     thereof is to be made against the indemnifying party under this Section
     4.06, notify the indemnifying party in writing of the commencement thereof
     and the indemnifying party shall have the right to participate in, and, to
     the extent the indemnifying party so desires, to assume the defense thereof
     with counsel mutually satisfactory to the parties.

5. MISCELLANEOUS

     5.01  EXPENSES; FINDERS FEES.  Neither party shall pay expenses and
finder fees for or to the other in connection with this transaction.  Each party
agrees to indemnify and hold the other party harmless from any liability for any
commission or compensation in the nature of a finder's fee to any broker or
other person (and the costs and expenses of defending against such liability or
asserted liability) claiming to have been hired or engaged by the party.

     5.02  REPLACEMENT OF CERTIFICATES FOR RESTRICTED COMMON STOCK.  Upon
receipt by the Company of evidence reasonably satisfactory to it of the loss,
theft, destruction or mutilation of any certificate evidencing any Restricted
Common Stock, the Company will execute, register and deliver, in lieu thereof, a
new certificate for an equal number of shares of Restricted Common Stock.  In
the case of loss, theft or destruction of a certificate, at the election of the
Company, the Purchaser may be required to provide an indemnity reasonably
satisfactory to the Company or to post a surety bond in an amount equal to the
value of the shares represented by the new certificate.

     5.03  NOTICE.  Any notice required to be given under the terms of this
Agreement shall be in writing, and shall be given in person, transmitted by
telecopier, e-mail or similar electronic communication, delivered by a
recognized overnight delivery service such as Federal Express or sent by mail
(certified or registered or air mail for addresses outside of the country of
origin), return receipt requested, postage prepaid and addressed to the Company
at 5935 Darwin Court, Carlsbad, California 92008, or such other address as the
Company may designate to Purchaser in writing and to the Purchaser, at the
address appearing at the beginning of this Agreement or such other address as
Purchaser may designate to the Company in writing.  Except as otherwise provided
herein, any notice so given shall be deemed delivered upon the earlier of (i)
actual receipt; (ii) receipt by sender of confirmation if telecopied or sent by
e-mail or similar electronic communication; (iii) two business days after
delivery to such overnight delivery service; or (iv) five business days after
deposit in the mail.

     5.04  SUCCESSORS AND ASSIGNS.  This Agreement shall be binding upon the
parties and their respective successors and assigns.

     5.05  SURVIVAL OF REPRESENTATIONS, ETC.  All covenants, representations
and warranties made by the parties herein shall survive the Closings and the
delivery of this Agreement and the shares of Restricted Common Stock purchased
hereunder.


                                  9


<PAGE>

     5.06  TERMINATION.  Purchaser's obligation to purchase Restricted
Common Stock under this Agreement shall terminate with respect to any purchase
obligations whose purchase dates under Paragraph 1.02 occur after Purchaser has
elected to terminate, in its entirety, all of Purchaser's rights and obligations
under the Letter of Intent ("LOI") dated June 11, 1998 and the Definitive
Agreement (as defined in the LOI) between the parties.

     5.07  SEVERABILITY.  Should any part of this Agreement for any reason
be declared invalid, such decision shall not affect the validity of any
remaining portion, which remaining portion shall remain in force and effect as
if this Agreement had been executed with the invalid portion thereof eliminated
and it is hereby declared the intention of the parties hereto that they would
have executed the remaining portion of this Agreement without including therein
any such part, parts, or portion which may, for any reason, be hereafter
declared invalid.

     5.08  GOVERNING LAW.  This Agreement shall be construed and enforced in
accordance with, and governed by, the laws of the State of California without
regard to its conflict of law provisions.

     5.09  CAPTIONS, FORM OF PRONOUNS.  The descriptive headings of the
various sections or parts of this Agreement are for convenience only and shall
not affect the meaning or construction of any of the provisions hereof.  All
pronouns used in this Agreement shall be deemed to include masculine, feminine
and neuter forms.

     5.10  AGREEMENT IS ENTIRE CONTRACT.  This Agreement constitutes the
entire contract between the parties hereto related to the purchase and sale of
Restricted Common Stock and no party shall be liable or bound to the other in
any manner by any warranties, representations or covenants except as
specifically set forth herein.

     5.11  THIRD PARTIES.  Nothing in this Agreement is intended to confer
upon any party, other than the parties hereto, and their respective permitted
successors and assigns, any rights, remedies, obligations, or liabilities under
or by reason of this Agreement, except as expressly provided herein.

     5.12  AMENDMENT AND WAIVER.  Any provision of this Agreement may be
amended and the observance of any term hereof may be waived (either
prospectively or retroactively and either generally or in a particular instance)
only with the written consent of the Company and the Purchaser.

     5.13  AFFILIATES.  References to Purchaser in this Agreement shall be
deemed to include direct or indirect subsidiaries of Purchaser.  The term
"Affiliate" shall have the meaning defined in the LOI.

     5.14  DISPUTE RESOLUTION.  In the event of any controversy or claim arising
out of or relating to any provision of this Agreement, the parties shall try to
settle their differences amicably between themselves.  Any unresolved disputes
arising between the parties relating to, arising out of or in any way connected
with this Agreement or any term or condition hereof, or the performance by
either party of its obligations hereunder, whether before or after termination
of this Agreement, shall be finally resolved by binding


                            10


<PAGE>

arbitration.  Whenever a party shall decide to institute arbitration 
proceedings, it shall give written notice to that effect to the other party.  
The party giving such notice shall refrain from instituting the arbitration 
proceedings for a period of sixty (60) days following such notice  The 
arbitration shall be held in San Diego, California according to the rules of 
the American Arbitration Association ("AAA") applicable to commercial 
securities matters of this nature.  The arbitration shall be conducted by a 
panel of three arbitrators appointed in accordance with AAA rules; provided, 
however, that each party shall within thirty (30) days after the institution 
of the arbitration proceedings appoint one arbitrator with the third 
arbitrator being chosen by the other two arbitrators.  If only one party 
appoints an arbitrator, then such arbitrator shall be entitled to act as the 
sole arbitrator to resolve the controversy.  Any arbitration hereunder shall 
be conducted in the English language and the arbitrator(s) shall apply the 
law set forth in Section 5.08.  All arbitrator(s) eligible to conduct the 
arbitration must agree to render their opinion(s) within thirty (30) days of 
the final arbitration hearing.  The arbitrator(s) shall have the authority to 
grant injunctive relief and specific performance, and to allocate between the 
parties the costs of arbitration in such equitable manner as he determines; 
provided, however, that each party shall bear its own costs and attorney's 
and witness' fees.  Notwithstanding the terms of this Section 5.14, a party 
shall also have the right to obtain prior to the arbitrator(s) rendering the 
arbitration decision, provisional remedies including injunctive relief or 
specific performance from a court having jurisdiction thereof.  The 
arbitrator(s) will, upon the request of either party, issue a written opinion 
of the findings of fact and conclusions of law and shall deliver a copy to 
each of the parties.  Decisions of the arbitrator(s) shall be final and 
binding on all of the parties.  Judgment on the award so rendered may be 
entered in any court having jurisdiction thereof. 


                                 11


<PAGE>

     The execution hereof by Purchaser shall constitute a contract between us
for the uses and purposes hereinabove set forth, and this Agreement may be
executed in any number of counterparts, each executed counterpart constituting
an original but all together only one agreement.

                                       THE IMMUNE RESPONSE CORPORATION
                                        
                                        By  s/Dennis J. Carlo
                                            ---------------------------------
                                        
                                        By  s/Charles J.Cashion
                                            ---------------------------------

ACCEPTED AND AGREED TO AS OF THE DAY AND YEAR AFORESAID.
                                        
                                        PURCHASER:
                                        AGOURON PHARMACEUTICALS, INC
                                        
                                        
                                        By  s/Peter Johnson
                                            ---------------------------------
                                        Peter Johnson
                                        President and Chief Executive Officer
                                        
                                        
                                        By  s/Gary Friedman
                                            ---------------------------------
                                        Gary Friedman
                                        Secretary





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