Exhibit 99.1

                              N E W S   R E L E A S E

          APHTON DETERMINES IT IS NOT IN ITS SHAREHOLDERS BEST INTEREST
       TO RESTRUCTURE ITS PARTNERSHIP AGREEMENT WITH AVENTIS PASTEUR; THE
                      EXISTING AGREEMENT REMAINS IN EFFECT

                                 March 31, 2003

          Miami, FL - Aphton Corporation (NASDAQ: APHT) - Aphton announced today
that  taking  into full  account the $20  million  financing  package  announced
earlier today, Aphton's Board of Directors determined that it is not in the best
interest of Aphton's  shareholders  to  restructure  the  existing  Co-Promotion
Agreement and License with Aventis Pasteur to treat human cancers with G17DT and
that the  Letter  of  Intent  (LOI) of  December  19,  2002 to  restructure  the
agreement with Aventis, will expire as of today.

          While  retaining its favorable  royalty  split,  which is in excess of
50%, in its  agreement  with Aventis  Pasteur for countries in North America and
Europe,  Aphton  will  pursue its primary  objective  of filing for  approval to
market G17DT for  monotherapy  for advanced  pancreatic  cancer  patients in the
European  Union,  Canada and Australia by September 2003. With the expiration of
the LOI  agreement,  Aphton will resume its intention to license,  in return for
royalties, up-front fees and milestone payments: a) G17DT to treat human cancers
in markets worldwide outside of North America and Europe,  including  especially
in Japan, with a focus there on gastric cancer therapy;  b) monoclonal  antibody
products to target gastrointestinal system cancers,  worldwide; and c) G17DT for
non-cancer therapy, to treat gastroesophageal reflux disease (GERD),  worldwide.
While pursuing these  objectives,  Aphton intends to reduce its spending  during
the next  twelve  months  by more  than 60% to less  than $16  million  from the
approximately  $40 million  during the twelve  months of fiscal year 2002.  This
amount is believed  sufficient to fund the highly focused  activities  discussed
above.

          Aphton  agrees  with the  prevalent  view that in the  current  market
environment,  biotechnology  companies have been essentially  separated into two
major  segments;  those with  commercial  products and those that are continuing
development work on potential commercial  products.  Aphton believes that it may
be able to move from the latter to one that has an approved  commercial  product
in a relatively  short  period of time.  The  transition  to having a commercial
product,  followed  by  revenues  and a  positive  cash flow is  consistent,  in
management's   opinion,  with  the  expectation  of  higher  values  for  Aphton
shareholders.  Aphton believes that it has reached the decisive turning point in
its corporate development and in the pursuit of its corporate objectives.

          Aphton's  anti-gastrin targeted therapy induces antibodies in patients
that bind to both gastrin 17 and  gly-gastrin  and remove them from  circulation
before they can bind to the cancer cell and initiate cell growth. Gastrin 17 and
gly-gastrin  are  believed  to be  central  growth  factors,  or the  initiating
signals, for cell  growth,  cell

<PAGE>

proliferation  and metastasis  (spread) in gastric,  i.e.  stomach,  pancreatic,
esophageal,  colorectal and other  gastrointestinal  (GI) system  cancers.  This
signaling  program is  accomplished  by gastrin  binding to the large numbers of
gastrin  receptors  which appear,  de novo, in the great  majority of cases,  on
tumor cell surfaces throughout the  gastrointestinal  system.  Interrupting this
process by  immunizing  the patient with  Aphton's  anti-gastrin  immunogen is a
precisely  "targeted"  immunotherapy.  This specificity of targeting only cancer
cells occurs because gastrin is not secreted and gastrin receptors are not found
on  cells  in the GI  system,  unless  they  are  malignant,  or on the  path to
malignancy,  except for those cells involved with normal acid secretion.  Hence,
inhibiting gastrin inhibits factors contributing to tumor growth and metastasis,
or spread. Aphton's anti-gastrin targeted therapy adds a biological dimension to
the treatment of gastrointestinal cancers.

          Aphton Corporation is a biopharmaceutical  company developing products
using its innovative targeted immunotherapy technology for neutralizing hormones
that participate in  gastrointestinal  system and reproductive system cancer and
non-cancer  diseases.  Aphton has strategic  alliances with Aventis  Pasteur for
treating  gastrointestinal  system and other cancers with G17DT in North America
and  Europe;  GlaxoSmithKline  for  reproductive  system  cancer and  non-cancer
diseases worldwide; and others.

Except for the historical  information  herein, the matters discussed herein are
forward-looking  statements that involve a number or risks and uncertainties and
are not a guarantee of future performance. Future results may vary significantly
based on a  number  of  factors  including,  but not  limited  to,  intellectual
property  risks,  risks in regulatory and market  acceptance of new products and
continuing  demand for same,  the impact of  competitive  products  and pricing,
changing  economic  conditions  and other risk  factors that are inherent in the
drug development process and the company's business including those set forth in
Aphton's  most recent 10-K and other  filings with the  Securities  and Exchange
Commission. It is not possible to predict or identify all such risk factors that
could cause actual  results to differ from expected or historical  results.  The
company's actual results could differ from these forward-looking  statements and
the company  undertakes  no obligation  to update  publicly any  forward-looking
statement, except as may be required under applicable securities law.

Contact: Aphton Corporation; Investor Relations, J.L. Whitmore, 305-374-7338.