STOCK PURCHASE AGREEMENT


          THIS AGREEMENT is made this 24th day of August, 2001, between APHTON
CORPORATION (the "Company"), a Delaware corporation, and the purchaser whose
name and address is set forth on the signature page hereof (the "Purchaser").

          IN CONSIDERATION of the mutual covenants contained in this Agreement,
the Company and the Purchaser agree as follows:

          Section 1. Authorization of Sale of the Shares. Subject to the terms
and conditions of this Agreement, the Company has authorized the sale of
1,187,503 shares of its common stock, par value $.001 per share (the "Common
Stock").

          Section 2. Agreement to Sell and Purchase the Shares. Simultaneously
with the execution and delivery of this Agreement, the Company is selling to the
Purchaser, and the Purchaser is buying from the Company, upon the terms
hereinafter set forth, the number of shares set forth on the signature page of
this Agreement (the "Shares") for an aggregate purchase price (the "Purchase
Price") set forth on the signature page of this Agreement.

          The Company may enter into purchase agreements in substantially the
form of this Agreement with certain other purchasers (collectively, the "Other
Purchasers") and expects to complete sales of Common Stock to them. The
Purchaser and the Other Purchasers are hereinafter sometimes collectively
referred to as the "Purchasers," and this Agreement and the purchase agreements
executed by the Other Purchasers are hereinafter sometimes collectively referred
to as the "Agreements." The terms of this Agreement shall be at least as
favorable to the Purchaser as the terms of agreements with Other Purchasers.

          Section 3. Payment and Delivery.

          3.1 Closing. Payment for the Shares shall be made to the Company in
Federal or other funds immediately available in New York City against delivery
of the Shares (such payment and delivery hereinafter referred to as the
"Closing") at 10:00 a.m., New York City time, on August 31, 2001, or at such
other time on the same or such other date, not later than September 4, 2001, as
shall be agreed by the Company and the Purchaser. The time and date of such
payment are hereinafter referred to as the "Closing Date." Payment shall be made
against delivery of the Shares to the address set forth on the signature page of
this Agreement, in such nominee name as specified by Purchaser.

          Certificates for the Shares shall be registered in the name of the
Purchaser or if so indicated on the signature page hereto, in the name of a
nominee designated by the Purchaser. The certificates evidencing the Shares
shall be delivered to the Purchaser on the Closing Date, with any transfer taxes
payable in connection with the transfer of the Shares to the Purchaser duly
paid, against payment of the Purchase Price therefor.

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          3.2 Legend. The certificate or certificates representing the Shares
shall contain a legend restricting transfer under the Securities Act of 1933, as
amended (the "Securities Act"), such legend to be substantially as follows:

          "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN
          ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER
          THE SECURITIES ACT OF 1933. SUCH SECURITIES MAY NOT BE SOLD,
          TRANSFERRED OR ASSIGNED IN THE ABSENCE OF AN EFFECTIVE
          REGISTRATION STATEMENT OR AN EXEMPTION THEREFROM UNDER SAID
          ACT THE LEGALITY OF WHICH IS CONFIRMED IN A LEGAL OPINION
          SATISFACTORY TO THE COMPANY."

          The certificate shall also include any legends required by any
applicable state securities laws.

          Section 4. Representations and Warranties of the Company. The Company
hereby represents and warrants to, and covenants with, the Purchaser that the
following are true and correct.

          4.1 Organization. The Company is a corporation duly incorporated,
validly existing as a corporation and in good standing under the laws of the
State of Delaware and has full corporate power and authority to own, lease and
operate its properties and assets, and to carry on its business as presently
conducted and as proposed to be conducted, each as described in the SEC Reports
(as defined herein). The Company is qualified to do business as a foreign
corporation in each jurisdiction in which the ownership or leasing of its
property or the conduct of its business requires such qualification, except
where failure to so qualify would not have a material adverse effect on the
Company.

          4.2 Authorization. This Agreement has been duly authorized, executed
and delivered and is a valid and binding obligation of the Company, enforceable
in accordance with its terms, except as enforceability may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or other similar
laws affecting creditors' and contracting parties' rights generally and except
as enforceability may be subject to general principles of equity (regardless of
whether enforceability is considered in a proceeding in equity or at law) and
except as the indemnification agreements contained in Section 9 hereof may be
legally unenforceable. The Shares have been duly authorized and, upon their
issuance and delivery pursuant to this Agreement, the Shares will be validly
issued, fully paid and nonassessable. The issuance and sale of the Shares will
not give rise to any preemptive right or similar right on behalf of any person
in existence either on the date hereof or immediately prior to the Closing.

          4.3 No Conflict. The execution and delivery of this Agreement do not,
and the consummation of the transactions contemplated hereby will not conflict
with, or result in any violation of, or default (with or without notice or lapse
of time, or both), or give rise to a right of termination, cancellation or
acceleration of any obligations or to a loss of a material benefit under, any
provision of the Certificate of Incorporation or Bylaws of the Company or any

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mortgage, indenture, lease or other agreement or instrument, permit, concession,
franchise, license, judgment, order, decree, statute, law, ordinance, rule or
regulation applicable to the Company, its properties or assets, the effect of
which would have a material adverse effect on the Company or impair or restrict
its power to perform its obligations as contemplated hereby.

          4.4 Accuracy of Reports and Information. The Company's common stock is
registered pursuant to Section 12(g) of the Securities Exchange Act of 1934, as
amended (the "Exchange Act"). All reports required to be filed by the Company
with the Securities and Exchange Commission (the "SEC" or the "Commission")
during the 12 months preceding the date of this Agreement pursuant to Section
13(a) or 15(d) of the Exchange Act (collectively, as such documents have since
the time of their filing been amended or supplemented, and including any such
document filed with the SEC subsequent to the date hereof, the "SEC Reports"),
have been duly filed, and as of their respective dates (if amended or superseded
by a filing prior to the date of the Agreement or the Closing Date, then the
date of such fling) were prepared in accordance with the applicable requirements
of the Exchange Act. Copies of all SEC Reports filed by the Company are
available to the Purchaser upon request. The Company will continue to file all
reports required to be filed under the Exchange Act. At the time they were filed
(if amended or superseded by a filing prior to the date of this Agreement or the
Closing Date, then as of the date of such filing), the SEC Reports did not
contain any untrue statement of a material fact or omit to state a material fact
necessary to make the statements made therein, in the light of the circumstances
under which they were made, not misleading. The Company is an issuer eligible to
use Form S-3 under the Securities Act for the resale of the Shares.

          4.5 Absence of Certain Developments. Except as disclosed in the SEC
Reports and as contemplated by this Agreement, since January 31, 2001, there has
not been:

          (a) any material adverse change in the business, condition (financial
or otherwise), results of operations or prospects of the Company;

          (b) any damage, destruction or loss, whether covered by insurance or
not, having a material adverse effect on the business or financial condition of
the Company;

          (c) any issuance of capital stock or of other rights to acquire
capital stock or securities convertible into capital stock, or any agreements
relating to such issuance, other than as contemplated by the Agreements;

          (d) any redemption, repurchase or other acquisition of common stock or
any declaration of any payment of any dividend or other distribution in cash,
stock or property with respect to the common stock, or any amendment to the
Articles of Incorporation or Bylaws of the Company;

          (e) any entry into any material contract or transaction, including
without limitation, any borrowing, repayment of indebtedness, capital
expenditure or business combination, other than in the ordinary course of
business consistent with past practice or as contemplated by the Agreements;

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          (f) any transfer of or rights granted under any material leases,
licenses, agreements, patents, trademarks, trade names or copyrights other than
those transferred or granted in the ordinary course of business; any change by
the Company in accounting principles or methods except insofar as may have been
required by a change in generally accepted accounting principles;

          (g) any contract, agreement, commitment or arrangement with respect to
any of the foregoing; or

          (h) any pending or, to the knowledge of the Company, threatened
litigation, proceeding (administrative or otherwise) or investigation against
the Company which individually or in the aggregate could result in any material
adverse change in the business, condition (financial or otherwise), or results
of operations of the Company.

          4.6 Governmental Consent, etc. No consent, approval or authorization
of or designation, declaration or filing with any governmental authority on the
part of the Company is required in connection with the valid execution and
delivery of this Agreement, or the offer, sale or issuance of the Shares, or the
consummation of any other transaction contemplated hereby, except such filings
as may be required to be made with the Securities and Exchange Commission, the
Nasdaq National Market and the National Association of Securities Dealers, Inc.
and filings, if any, to be made in compliance with applicable blue sky
requirements.

          4.7 Intellectual Property Rights. Except as disclosed in the SEC
Reports, the Company has sufficient trademarks, trade names, patent rights,
copyrights and licenses to conduct its business as contemplated in the SEC
Reports; the expiration of any trademark, trade name, patent right, copyright or
license would not have a material adverse effect on the condition (financial or
otherwise), business prospects or results of operations of the Company; to the
best of the Company's knowledge, neither the Company nor its products is
infringing or will infringe any trademark, trade name, patent right, copyright,
license, trade secret or other similar right of others currently in existence;
and there is no claim being made against the Company regarding any trademark,
trade name, patent, copyright, license, trade secret or other intellectual
property right which could have a material adverse effect on the condition
(financial or otherwise), or results of operations of the Company.

          4.8 No Registration. Subject to the accuracy of the Purchaser's
representations herein, it is not necessary in connection with the offer, sale
and delivery of the Shares to the Purchaser in the manner contemplated by this
Agreement to register the Shares under the Securities Act.

          4.9 No Litigation. There is no claim, action, suit, proceeding or
investigation pending by or before any court, arbitration tribunal or
administrative agency or, to the Company's knowledge, currently threatened
against the Company or any of its respective directors or officers, in their
capacities as such, that questions the validity of this Agreement or the
Agreements or the issuance of the Shares, or the right of the Company to enter
into this Agreement or the Agreements.

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          4.10 Capitalization. There have been no changes in the capitalization
of the Company from that set forth in the SEC Reports, including the authorized
capital stock; the number of shares issued and outstanding; the number of shares
reserved for issuance pursuant to stock option, employee benefit or other plans;
the number of shares reserved for issuance or issuable pursuant to securities
exercisable for, or convertible into or exchangeable for, any shares of common
stock; and the number of shares of common stock reserved for issuance with
respect to sales pursuant to the Agreements.

          Section 5. Representations, Warranties and Covenants of the Purchaser.
The Purchaser represents and warrants to, and covenants with, the Company that:

          5.1 Accredited Investor. The Purchaser is an "accredited investor"
within the meaning of Rule 501(a) 1, 2, 3 or 7 under the Securities Act.

          5.2 Investment Representations. The Purchaser is aware that the Shares
have not been registered under the Securities Act and any applicable state
securities laws, and agrees that the Shares will not be offered or sold in the
absence of registration under the Securities Act and any applicable state
securities laws or an exemption from the registration requirements of the
Securities Act and any applicable state securities laws.

          The Purchaser understands that the offering and sale of the Shares is
intended to be exempt from registration under the Securities Act, by virtue of
Section 4(2) and/or Section 4(6) of the Securities Act and the provisions of
Regulation D promulgated thereunder, based, in part, upon the representations,
warranties and agreements contained in this Agreement and the Company may rely
on such representations, warranties and agreements in connection therewith.

          The Purchaser will not, directly or indirectly, offer, sell, pledge,
transfer or otherwise dispose of (or solicit offers to buy, purchase or
otherwise acquire or take a pledge of) any of the Shares, except in compliance
with the Securities Act and the applicable rules and regulations of the
Commission thereunder.

          The Purchaser is acquiring the Shares for its own account and for
investment, and not with a view to the resale or distribution thereof; it has no
present intention of selling, negotiating, or otherwise disposing of the Shares
in violation of the U.S. securities laws. The Purchaser's financial condition
and investments are such that it is in a financial position to hold the Shares
for an indefinite period of time and to bear the economic risk of, and withstand
a complete loss of, such Shares. In addition, by virtue of its expertise, the
advice available to it, and its previous investment experience, the Purchaser
has extensive knowledge and experience in financial and business matters,
investments, securities, and private placements and the capability to evaluate
the merits and risks of the transactions contemplated by this Agreement.

          5.3 Restrictions on Sale. The Purchaser will not, prior to the date on
which the Registration Statement referred to in Section 9.2 is first declared
effective by the Commission (the "Effective Date"), if then prohibited by law or
regulation, sell, offer to sell, solicit offers to buy, dispose of, loan, pledge
or grant any right with respect to (collectively, a "Disposition"), the Shares,
nor will the Purchaser engage in any hedging or other transaction which is
designed or

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could reasonably be expected to lead to or result in a Disposition of Shares by
the Purchaser or any person or entity. Such prohibited hedging or other
transaction would include, without limitation, effecting any short sale or
having in effect a short position (whether such short sale or position is
against the box and regardless of when such position was entered into) or any
purchase, sale or grant of any right (including, without limitation, any put or
call option) with respect to the Shares or with respect to any security (other
than a broad-based market basket or index) that includes or derives any
significant part of its value from the Shares.

          5.4 Authority. The Purchaser further represents and warrants to, and
covenants with, the Company that (i) the Purchaser has full right, power,
authority and capacity to enter into this Agreement and to consummate the
transactions contemplated hereby and (ii) upon the execution and delivery of
this Agreement, this Agreement shall constitute a valid and binding obligation
of the Purchaser, enforceable in accordance with its terms, except as
enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or similar laws affecting creditors' and contracting
parties' rights generally and except as enforceability may be subject to general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law) and except as the indemnification agreements
in Section 9 hereof may be legally unenforceable.

          5.5 Purchaser Review. The Purchaser hereby represents and warrants
that the Purchaser has carefully examined the SEC Reports filed during the 12
months prior to the date of this Agreement and acknowledges that the Company has
made available to the Purchaser all documents and information that it has
requested relating to the Company and has provided answers to all of its
questions concerning the Company and the Shares. In evaluating the suitability
of the acquisition of the Shares hereunder, the Purchaser has not relied upon
any representations or other information (whether oral or written) other than as
set forth in the SEC Reports or as contained herein.

          5.6 Legends. The Purchaser will not make any sale of the Shares
without complying with the provisions of this Agreement and without causing the
prospectus delivery requirements under the Securities Act to be satisfied, and
the Purchaser acknowledges that certificates evidencing the Shares will be
imprinted with a legend in substantially the form provided in Section 3.2 of
this Agreement (and a stop-transfer order may be placed against transfer of the
certificates for the Shares). The Purchaser acknowledges that there may
occasionally be times when the Company determines that it must suspend the use
of the prospectus forming part of the Registration Statement, as set forth in
Section 9.8.

          5.7 Notification. The Purchaser will notify the Company promptly of
the sale of any of its Shares, other than (i) sales pursuant to a Registration
Statement contemplated in Section 9 of this Agreement and (ii) sales following
termination of the transfer restrictions pursuant to Section 9.4, and the
Purchaser will furnish any information reasonably requested by the Company
(including a legal opinion in form and substance satisfactory to the Company and
its counsel) to evidence the exemption from the registration requirements of the
Securities Act, the applicable rules and regulations of the Commission
thereunder, and state securities laws, in reliance upon which such sales have
been made.

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          5.8 HSR. Based on (i) the Company having no more than 17,386,996
shares of common stock outstanding at the Closing Date (after giving effect to
the sale and purchase of shares of Common Stock pursuant to the Agreements), the
Purchaser, together with its ultimate parent entity and all entities controlled
by the same ultimate parent as the Purchaser (such entities, including the
Purchaser, hereinafter collectively referred to as the "Purchaser Affiliates"),
will not hold in excess of 10% of the Company's outstanding voting securities as
a result of the sale and purchase of Shares pursuant to this Agreement, and (ii)
all voting securities of the Company that the Purchaser Affiliates will hold,
directly or indirectly, at the Closing Date (after giving effect to the sale and
purchase of Shares pursuant to this Agreement), will be held solely for the
purpose of investment such that these securities will be held by the Purchaser
Affiliates with no intention on the part of any of them to participate in the
formulation, determination or direction of the basic business decisions of the
Company. As a result of (i) and (ii), the Purchaser Affiliates are relying on
the exemption available to them as passive investors under Section 7A(c)(9) of
the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and
regulations promulgated thereunder (including 16 C.F.R. Sec. 802.9) in their
determination that the sale and purchase of Shares pursuant to this Agreement
does not require them to submit any HSR Notification and Report Form.

          5.9 Confidentiality. The Purchaser will hold in confidence all
information concerning this Agreement and the placement of shares hereunder
until the earlier of such time as the Company has made a public announcement
concerning this Agreement and the placement of Shares hereunder, or this
Agreement is terminated. Purchaser also expressly agrees to hold in confidence
any information or data regarding the Company it receives pursuant to this
Agreement (including, without limitation, Sections 9.6 and 9.7 of this
Agreement) that is not otherwise properly in the public domain. Purchaser agrees
not to divulge, communicate or disclose, except as may be required by law or for
the performance of this Agreement, or use to the detriment of the Company or for
the benefit of any other person or persons, or misuse in any way, any
confidential information of the Company.

          Section 6. Survival of Representations, Warranties and Agreements.
Notwithstanding any investigation made by any party to this Agreement, all
covenants, agreements, representations and warranties made by the Company and
the Purchaser herein and in the certificates representing the Shares delivered
pursuant hereto shall survive the execution of this Agreement, the delivery to
the Purchaser of the Shares being purchased and the payment therefor.

          Section 7. Purchaser's Conditions to Closing. The obligations of the
Purchaser to purchase and pay for the Shares on the Closing Date are subject to
the following conditions:

          (a) The Purchaser shall have received on the Closing Date a
     certificate, dated the Closing Date and signed by an executive officer of
     the Company, to the effect that:

               (i) the representations and warranties of the Company contained
          in this Agreement are true and correct in all material respects as of
          the Closing Date;

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               (ii) the Company has complied in all material respects with all
          of the agreements to be performed by the Company on or prior to the
          Closing Date; and

               (iii) the aggregate number of shares of Common Stock to be issued
          by the Company to the Purchasers will not exceed 20% of the Company's
          outstanding shares.

          The officer signing and delivering such certificate may rely upon the
     best of his or her knowledge as to proceedings threatened.

          (b) The Purchaser shall have received a copy of resolutions of the
     Board of Directors approving the execution, delivery and performance of
     this Agreement and the transactions contemplated hereby, certified to be
     true and correct by the Chief Executive Officer of the Company.

          Section 8. Company's Conditions to Closing. The Company's obligation
to issue the Shares to the Purchaser is subject to the following conditions:

          (a) The Company shall have received Federal or other immediately
     available funds in the full amount of the Purchase Price.

          (b) The representations and warranties made by the Purchasers shall be
     accurate in all material respects and the undertakings of the Purchasers to
     be fulfilled on or prior to the Closing shall have been fulfilled.

     Section 9. Registration of the Shares; Compliance with the Securities Act.

          9.1 Definitions. For the purpose of this Section 9:

          (a) the term "Registration Statement" shall mean the registration
statement required to be filed by Section 9.2 below, and shall include any
preliminary prospectus, final prospectus, exhibit or amendment included in or
relating to such registration statement; and

          (b) the term "untrue statement" shall include any untrue statement or
alleged untrue statement, or any omission or alleged omission to state in the
Registration Statement a material fact required to be stated therein or
necessary to make the statements therein (in the case of a preliminary or final
prospectus, in the light of the circumstances under which they were made) not
misleading.

          9.2 Registration Procedures and Expenses. The Company shall:

          (a) following the execution of this Agreement, use its reasonable best
efforts to prepare and file with the SEC by the date ten (10) days after the
Closing Date but in any event by the date twenty (20) days after the Closing
Date, a Registration Statement under the Securities Act on a form which is
appropriate to register the resale of Shares by the Purchaser, and use its
reasonable best efforts to respond to any comment by the SEC relating to the
Registration

<PAGE>

Statement before the tenth (10th) day following receipt of such comment, but in
any event before the twentieth (20th) day after such receipt;

          (b) use its reasonable best efforts, subject to receipt of necessary
information from the Purchaser, to cause such registration to become effective
within 180 days after the Closing Date;

          (c) prepare and file with the SEC such amendments and supplements to
such Registration Statement(s) and the prospectus(es) used in connection
therewith as may be necessary to keep such Registration Statement(s) effective
until the earliest to occur of (i) the date which is two years after the
Effective Date, (ii) such time as all the Shares have been sold by the
Purchasers, and (iii) such time as the Shares are eligible for resale pursuant
to Rule 144 under the Securities Act;

          (d) furnish to the Purchaser with respect to the Shares registered on
the Registration Statement such number of copies of prospectuses in conformity
with the requirements of the Securities Act and such other documents as the
Purchaser may reasonably request, in order to facilitate the public sale or
other disposition of all or any of the Shares by the Purchaser; provided,
however, that the obligation of the Company to deliver copies of prospectuses to
the Purchaser shall be subject to the receipt by the Company of reasonable
assurances from the Purchaser that the Purchaser will comply with the applicable
provisions of the Securities Act and of such other securities laws as may be
applicable in connection with any use of such prospectuses;

          (e) file such documents as may be required of the Company for normal
securities law clearance for the resale of the Shares in such states of the
United States as may be reasonably requested by the Purchaser; provided,
however, that the Company shall not be required in connection with this
paragraph (e) to qualify as a foreign corporation or execute a general consent
to service of process in any jurisdiction;

          (f) subject to Section 19 of this Agreement, bear all expenses in
connection with the procedures in paragraphs (a) through (e) of this Section 9.2
and the registration of the Shares on such Registration Statement(s) and the
satisfaction of the blue sky laws of such states, and other than underwriting
discounts and selling commissions or expenses required by law to be borne by the
Purchaser; and

          (g) until the Effective Date, the Company shall pay to the Purchaser,
on a monthly basis, a liquidated damages penalty of 1.0% of the Purchase Price
for each month that the Registration Statement or a pro rata amount for the
number of days in a month (i) has not been filed within twenty (20) days after
the Closing Date, or (ii) has not become effective within 180 days of the
Closing Date, unless the Registration Statement has not become effective as a
result of the Purchaser's failure to provide information necessary for
completion of the Registration Statement.

          9.3 Underwriter. The Company understands that the Purchaser disclaims
being an "underwriter" (as such term is defined under the Securities Act and the
rules and

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regulations promulgated thereunder (an "Underwriter")), but the Purchaser being
deemed an Underwriter shall not relieve the Company of any obligation it has
hereunder.

          9.4 Termination of Obligations. The obligations of the Company
pursuant to Sections 9.2, 9.3 and 9.7 hereof shall cease and terminate upon the
earlier to occur in the case of the Shares, (i) the third anniversary of the
Closing Date and (ii) such time as all of the Shares have been sold by the
Purchaser.

          9.5 Indemnification.

          (a) The Company agrees to indemnify and hold harmless the Purchaser
(and each of its officers, directors, partners or persons, if any, who controls
such Purchaser within the meaning of Section 15 of the Securities Act) (the
"Purchaser Indemnitees") from and against any losses, claims, damages or
liabilities to which such Purchaser Indemnitee may become subject (under the
Securities Act or otherwise) insofar as such losses, claims, damages or
liabilities (or actions or proceedings in respect thereof) arise out of, or are
based upon, any untrue statement of a material fact contained in a Registration
Statement or any omission to state a material fact required to be stated therein
or necessary to make the statements contained therein not misleading relating to
the Shares on the effective date thereof, or arise out of any failure by the
Company to fulfill any undertaking included in a Registration Statement, and the
Company will, as incurred, reimburse such Purchaser Indemnitee for any legal or
other expenses reasonably incurred in investigating, defending or preparing to
defend any such action, proceeding or claim; provided, however, that the Company
shall not be liable in any such case to the extent that such loss, claim, damage
or liability arises out of, or is based upon, an untrue statement made in such
Registration Statement in reliance upon and in conformity with written
information furnished to the Company by or on behalf of the Purchaser
specifically for use in preparation of the Registration Statement.

          (b) The Purchaser agrees to indemnify and hold harmless the Company
(and each of its officers, directors, partners or persons, if any, who controls
the Company within the meaning of Section 15 of the Securities Act) (the
"Company Indemnitees"), from and against any losses, claims, damages or
liabilities to which such Company Indemnitee may become subject (under the
Securities Act or otherwise), insofar as such losses, claims, damages or
liabilities (or actions of proceedings in respect thereof) arise out of, or are
based upon, any untrue statement contained in a Registration Statement or any
omission to state a material fact required to be stated therein or necessary to
make the statements contained therein not misleading relating to the Shares on
the effective date thereof if such untrue statement was made in reliance upon
and in conformity with written information furnished by or on behalf of the
Purchaser specifically for use in preparation of the Registration Statement, and
the Purchaser will, as incurred, reimburse such Company Indemnitee for any legal
or other expenses reasonably incurred in investigating, defending or preparing
to defend any such action, proceeding or claim; provided, however, that to the
extent that any such damages relate to or arise from the resale of any Shares,
the Purchaser shall in no event be liable for an amount in excess of the
proceeds actually received by the Purchaser upon any sale of Shares pursuant to
the Registration Statement.

          (c) Promptly after receipt by any indemnified person of a notice of a
claim or the beginning of any action in respect of which indemnity is to be
sought against an indemnifying

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person pursuant to this Section 9.5, such indemnified person shall notify the
indemnifying person in writing of such claim or of the commencement of such
action, and, subject to the provisions hereinafter stated, in case any such
action shall be brought against an indemnified person and such indemnifying
person shall have been notified thereof, such indemnifying person shall be
entitled to participate therein, and, to the extent that it shall wish, to
assume the defense thereof, with counsel reasonably satisfactory to such
indemnified person. After notice from the indemnifying person to such
indemnified person of its election to assume the defense thereof, such
indemnifying person shall not be liable to such indemnified person for any legal
expenses subsequently incurred by such indemnified person in connection with the
defense thereof; provided, however, that if there exists or shall exist a
conflict of interest that would make it inappropriate in the reasonable judgment
of the indemnified person for the same counsel to represent both the indemnified
person and such indemnifying person or any affiliate or associate thereof, the
indemnified person shall be entitled to retain its own counsel at the expense of
such indemnifying person.

          9.6 Information Available. So long as any registration statement is
effective covering the resale of Shares, the Company will furnish to the
Purchaser:

          (a) as soon as practicable after available (but in the case of the
Company's Annual Report to Stockholders, within 90 days after the end of each
fiscal year of the Company), one copy of (i) its Annual Report to Stockholders
(which Annual Report shall contain financial statements audited in accordance
with generally accepted accounting principles in the United States of America by
a national firm of certified public accountants), (ii) if not included in
substance in the Annual Report to Stockholders, its annual report on Form 10-K,
(iii) each of its Quarterly Reports to Stockholders, its quarterly report on
Form 10-Q, and any interim reports on Form 8-K and (iv) a full copy of the
Registration Statement covering the Shares (the foregoing, in each case,
excluding exhibits); and

          (b) upon the reasonable request of the Purchaser, all exhibits
excluded by the parenthetical to subparagraph (a)(iv) of this Section 9.6 and
all other information that is generally available to the public; and the
Company, upon the reasonable request of the Purchaser, will meet with the
Purchaser or a representative thereof at the Company's headquarters, at the
Purchaser's expense, to discuss all information relevant for disclosure in any
registration statement covering the Shares and will otherwise cooperate with any
Purchaser conducting an investigation for the purpose of reducing or eliminating
such Purchaser's exposure to liability under the Securities Act, including the
production of information at the Company's headquarters.

          9.7 Rule 144 Reporting. With a view to making available the benefits
of certain rules and regulations of the SEC which may at any time permit the
sale of the Shares to the public without registration, the Company agrees to use
its best efforts to:

          (a) Make and keep public information available, as those terms are
understood and defined in Rule 144 under the Securities Act;

<PAGE>

          (b) Use its reasonable best efforts to file with the SEC in a timely
manner all reports and other documents required of the Company under the
Securities Act and the Exchange Act;

          (c) Furnish to the Purchaser forthwith upon request a written
statement by the Company as to its compliance with the reporting requirements of
said Rule 144, and of the Securities Act and the Exchange Act, a copy of the
most recent annual or quarterly report of the Company, and such other reports
and documents of the Company and other information in the possession of or
reasonably obtainable by the Company as the Purchaser may reasonably request in
availing itself of any rule or regulation of the SEC allowing the Purchaser to
sell Shares without registration.

          9.8 Transfer of Shares After Registration; Suspension.

          (a) The Purchaser agrees that it will not effect any disposition of
the Shares or its right to purchase the Shares that would constitute a sale
within the meaning of the Securities Act except as contemplated in the
Registration Statement referred to in Section 9.2 and as described below or as
otherwise permitted by law, and that it will promptly notify the Company of any
changes in the information set forth in the Registration Statement regarding the
Purchaser or its plan of distribution.

          (b) The Company shall, upon the occurrence or existence of any pending
corporate development that, in the sole discretion of the Company, makes it
appropriate to suspend the availability of the Registration Statement and the
related prospectus, give notice to the Purchaser that the availability of the
Registration Statement is suspended (a "Deferral Notice") and, upon receipt of
any Deferral Notice, the Purchaser agrees not to sell any Shares until such
Purchaser's receipt of copies of a supplemented or amended prospectus prepared
by the Company or until it is advised in writing by the Company that the
prospectus may be used. The Company will use its reasonable best efforts to
ensure that the use of the prospectus may be resumed as soon as, in the sole
judgment of the Company, public disclosure of the corporate development would
not be prejudicial to or contrary to the interests of the Company or, if
necessary to avoid unreasonable burden or expense, as soon as practicable
thereafter. The Purchaser hereby agrees that upon receipt of any Deferral Notice
from the Company, the Purchaser shall, and shall cause each of its officers,
directors, employees, affiliates, advisors, agents and representatives to, keep
confidential all nonpublic information set forth in such notice, including the
existence and terms of such Deferral Notice.

          Section 10. Other Agreements.

          10.1 No Stabilization or Manipulation. The Purchaser covenants and
agrees that it has not taken within the thirty (30) trading days preceding the
date of this Agreement and will not take within the twenty (20) trading day
period subsequent to the Effective Date, directly or indirectly, any action
designed to or which might reasonably be expected to cause or result in the
stabilization or manipulation of the price of the common stock of the Company to
facilitate the sale or resale of the Shares, including, without limitation, any
short selling of shares of the common stock of the Company.

<PAGE>

          10.2 Subsequent Placements. From the date hereof until the Effective
Date, the Company will not, directly or indirectly, offer, sell, grant any
option to purchase, or otherwise dispose of (or announce any offer, sale, grant
or any option to purchase or other disposition of) any of its equity or equity
equivalent securities, including without limitation any debt, preferred stock or
other instrument or security that is, at any time during its life and under any
circumstances, convertible into or exchangeable for common stock (any such
offer, sale, grant, disposition or announcement being referred to as a
"Subsequent Placement"), unless (i) the Company delivers to the Purchaser a
written notice (the "Subsequent Placement Notice") of its intention to effect
such Subsequent Placement, which Subsequent Placement Notice shall describe in
reasonable detail the proposed terms of such Subsequent Placement, the amount of
proceeds intended to be raised thereunder, the person with whom such Subsequent
Placement is proposed to be effected, and attached to which shall be a term
sheet or similar document relating thereto and (ii) the Purchaser shall not have
notified the Company by 5:00 p.m. (New York City time) on the fifth calendar day
after its receipt of the Subsequent Placement Notice of its willingness to
provide financing to the Company on the same terms set forth in the Subsequent
Placement Notice. If the Purchaser shall fail to so notify the Company of its
willingness to participate in the Subsequent Placement, the Company may effect
such Subsequent Placement on the terms and to the persons set forth in the
Subsequent Placement Notice and to any of the Other Purchasers that have elected
to participate in the Subsequent Placement. If all Purchasers indicate a
willingness to provide financing in an aggregate amount that is in excess of the
amount set forth in the Subsequent Placement Notice, then the Purchaser will be
entitled to provide financing pursuant to such Subsequent Placement Notice up to
an amount equal to the Purchaser's pro rata portion of the aggregate purchase
price paid for the Shares under this Agreement, but the Company shall not be
required to accept financing from the Purchasers in an amount in excess of the
amount set forth in the Subsequent Placement Notice. The foregoing shall not
apply to the grant of options or warrants, or the issuance of additional
securities, (i) to any of the Other Purchasers pursuant to the Agreements
provided they are on terms no more favorable than provided to the Purchaser
under the Agreement or (ii) to any employees or consultants under any duly
authorized Company stock option, restricted stock plan or stock purchase plan.

          10.3 Additional Issuance of Shares. If at any time from and after the
date hereof until the date that is twelve (12) months after the Effective Date,
the Company shall issue shares of common stock or rights, warrants, options or
other securities or debt that are convertible into or exchangeable for shares of
common stock ("Common Stock Equivalents"), entitling any person to acquire
shares of common stock at a price per share (the "Lesser Per Share Price") less
than the per Share Purchase Price, then the Company shall issue to the
Purchaser, no later than 10 calendar days following the issuance of such shares
of common stock or Common Stock Equivalents, such additional number of shares
(the "Additional Shares") of common stock equal to the excess of (a) the
quotient obtained by dividing the aggregate Purchase Price paid by the Purchaser
(as set forth on the signature page of this Agreement) divided by the Lesser Per
Share Price over (b) the quotient obtained by dividing the aggregate Purchase
Price paid by the Purchaser divided by the per Share Purchase Price. For such
purposes, in connection with any issuance of Common Stock Equivalents, (x) the
maximum number of shares of common stock potentially issuable at any time upon
conversion, exercise or exchange of such Common Stock

<PAGE>

Equivalents (the "Deemed Number") shall be deemed to be outstanding upon
issuance of such Common Stock Equivalents and (y) the price per share applicable
to such Common Stock Equivalents shall be deemed to equal the minimum dollar
value of consideration payable to the Company to purchase such Common Stock
Equivalents and to convert, exercise or exchange them into common stock, divided
by the Deemed Number. The shares of common stock referred to in this section
shall be subject to proportional adjustment in the event of any subdivision,
combination or consolidation of the Company's outstanding common stock or any
payment by the Company of a dividend or other distribution of shares of common
stock to holders of common stock. The foregoing shall not apply to the grant of
options or warrants, or the issuance of additional securities, (i) to any Other
Purchasers pursuant to the Agreements provided they are on terms no more
favorable than provided to the Purchaser under the Agreement or (ii) to any
employees or consultants under any duly authorized Company stock option,
restricted stock plan or stock purchase plan.

          Section 11. Placement Agent's Fee. The Purchaser acknowledges that the
Company intends to pay to UBS Warburg LLC, in its capacity as the placement
agent for the Shares, a fee in respect of the sale of the Shares to the
Purchaser. Each of the parties to this Agreement hereby represents that, on the
basis of any actions and agreements by it, there are no other brokers or finders
entitled to compensation in connection with the sale of the Shares to the
Purchaser.

          Section 12. Notices. All notices, requests, consents and other
communications hereunder shall be in writing, shall be mailed by first class
registered or certified mail, postage prepaid, and shall be deemed given when so
mailed;

          (a) if to the Company, to Aphton Corporation, 80 S.W. 8th Street,
Suite 2160, Miami, Florida 33149, Attention: Philip C. Gevas, Chief Executive
Officer, with a copy to White & Case LLP, 1155 Avenue of the Americas, New York,
New York 10036, Attention: Timothy B. Goodell, Esq., or to such other person at
such other place as the Company shall designate to the Purchaser in writing;

          (b) if to the Purchaser, at its address as set forth at the end of
this Agreement, or at such other address or addresses as may have been furnished
to the Company in writing; or

          (c) if to any transferee or transferees of the Purchaser, at such
address or addresses as shall have been furnished to the Company at the time of
the transfer or transfers, or at such other address or addresses as may have
been furnished by such transferee or transferees to the Company in writing.

          Section 13. Entire Agreement. This Agreement embodies the entire
agreement and understanding between the parties hereto with respect to the
subject matter hereof and supersedes all prior oral or written agreements and
understandings relating to the subject matter hereof. No statement,
representation, warranty, covenant or agreement of any kind not expressly set
forth in this Agreement shall affect, or be used to interpret, change or
restrict, the express terms and provisions of this Agreement.

<PAGE>

          Section 14. Amendments. This Agreement may not be modified or amended
except pursuant to an instrument in writing signed by the Company and by the
Purchaser.

          Section 15. Headings. The headings of the various sections of this
Agreement have been inserted for convenience of reference only and shall not be
deemed to be part of this Agreement.

          Section 16. Severability. In case any provision contained in this
Agreement should be invalid, illegal or unenforceable in any respect, the
validity, legality and enforceability of the remaining provisions contained
herein shall not in any way be affected or impaired thereby.

          Section 17. Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of New York and the United
States of America.

          Section 18. Counterparts. This Agreement 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, and shall become
effective when one or more counterparts have been signed by each party hereto
and delivered to the other party.

          Section 19. Expenses. Each of the parties shall pay its own fees and
expenses (including the fees of any attorneys, accountants, appraisers or others
engaged by such party) in connection with this Agreement and the transactions
contemplated hereby whether or not the transactions contemplated hereby are
consummated; provided, however, that the Company shall pay reasonable fees and
expenses of legal counsel for the Purchasers, subject to an aggregate limit of
$20,000 (the "Reimbursed Expenses"). The amount of the Reimbursed Expenses paid
with respect to counsel for each Purchaser shall equal an amount proportional to
such Purchaser's share in the aggregate proceeds paid by the Purchasers to the
Company for the Shares.

<PAGE>


          IN WITNESS WHEREOF, the parties hereto have caused this Agreement to
be executed by their duly authorized representatives the day and year first
above written.



                               APHTON CORPORATION



                               By:
                                  ---------------------------------------------
                                  Name:   Philip C. Gevas
                                  Title:  Chairman, President and Chief
                                          Executive Officer



<PAGE>


  Print or Type:

  Name of Purchaser (Institution)                      _____________________

  Tax ID No.:                                          _____________________

  Address:                                             _____________________

                                                       _____________________

  Telephone:                                           _____________________

  Facsimile:                                           _____________________

  Telex:                                               _____________________

  Name in which the Shares should be
  registered (if different):                           _____________________

  Relationship between the Purchaser
  and the person or entity in whose name
  the Shares should be registered (if different):      _____________________

  Address to which the Shares shall be delivered:      _____________________

                                                       _____________________

                                                       _____________________



  Signature by:                                        _____________________

  Name of Individual representing
  Purchaser:                                           _____________________

  Title of Individual representing
  Purchaser:                                           _____________________

  NUMBER OF SHARES TO BE PURCHASED:                    _____________________

  PER SHARE PURCHASE PRICE:                            _____________________

  AGGREGATE PURCHASE PRICE:                            _____________________