Exhibit 99.1

Progenics Pharmaceuticals Successfully Completes Two, Phase 1 Clinical Studies
of Oral Methylnaltrexone

     TARRYTOWN, N.Y.--(BUSINESS WIRE)--May 25, 2004--

          Drug Well Tolerated; Phase 2 Studies Planned in Chronic-Pain
                    Patients with Opioid-Induced Constipation

     Progenics Pharmaceuticals, Inc. (Nasdaq: PGNX) today announced that it has
completed phase 1 clinical trials of two different oral formulations of its
investigational drug methylnaltrexone (MNTX). Preliminary analysis of data from
61 healthy volunteers who received study medication at three dose levels
indicated that the drug was well tolerated and exhibited predictable
pharmacokinetics. The announcement of the completion of phase 1 is scheduled to
be made today at this year's annual shareholder meeting at the Company's
headquarters in Tarrytown.
     "Based on our timely and successful completion of these phase 1 studies, we
have selected an oral formulation and dose levels of MNTX that we plan to test
in phase 2 clinical trials later this year in chronic-pain patients with
opioid-induced constipation," said Robert J. Israel, M.D., Progenics' Senior
Vice President, Medical Affairs. "Drug absorption was found to be within
expected limits, and there were no drug-related serious adverse events in these
studies."
     Of the 25-million Americans with chronic pain, approximately four million
receive opioids on a daily basis, and, as a consequence, many experience
debilitating constipation which is often not responsive to laxatives and stool
softeners. There are currently no FDA-approved therapies for opioid-induced
constipation. The Company believes that oral MNTX may be useful for the
treatment of opioid-induced constipation in patients with chronic pain.
     Progenics has ongoing clinical programs for MNTX with three dosage forms:
Subcutaneous MNTX is the subject of two, pivotal phase 3 clinical trials in
opioid-induced constipation in patients with advanced medical illness;
intravenous MNTX is being studied in a phase 2 trial for treatment of
post-operative ileus; and oral MNTX is being developed for relief of
opioid-induced constipation in patients with chronic pain. The Company believes
that the ability to deliver MNTX using three dosage forms and routes of
administration represents a significant benefit. Each form is potentially useful
in a variety of clinical applications where rapid onset of action, dosing
flexibility, and ease of use can be tailored to fit the needs of the patient.

     Company Profile

     Progenics Pharmaceuticals, Inc., of Tarrytown, NY, is a biopharmaceutical
company focusing on the development and commercialization of innovative
therapeutic products to treat the unmet medical needs of patients with
debilitating conditions and life-threatening diseases. The Company has five
product candidates in clinical development and several others in preclinical
development. In symptom management and supportive care, the Company is
developing methylnaltrexone (MNTX) to treat the debilitating side effects of
opioid-based pain relievers without interfering with pain relief. MNTX is in
pivotal phase 3 clinical testing for treatment of opioid-induced constipation in
patients with advanced medical illness and may be the Company's first product
candidate to be approved for marketing. In the area of HIV infection, the
Company is developing viral-entry inhibitors, including PRO 542, a genetically
engineered molecule designed to selectively target and neutralize HIV (in phase
2 studies), and PRO 140, a monoclonal antibody designed to target the HIV
coreceptor CCR5 (in phase 1 studies). In addition, the Company is conducting
research on a novel prophylactic HIV vaccine. The Company is developing
immunotherapies for prostate cancer, including monoclonal antibodies directed
against prostate-specific membrane antigen (PSMA), a protein found on the
surface of prostate cancer cells. The Company is also developing vaccines
designed to stimulate an immune response to PSMA. A recombinant PSMA vaccine is
in phase 1 clinical testing. The Company is also studying a cancer vaccine, GMK,
in phase 3 clinical trials for the treatment of malignant melanoma.

     DISCLOSURE NOTICE: The information contained in this document is current as
of May 25, 2004. This press release contains forward-looking statements. Any
statements contained herein that are not statements of historical fact may be
forward-looking statements. When the Company uses the words 'anticipates,'
'plans,' 'expects' and similar expressions, it is identifying forward-looking
statements. Such forward-looking statements involve risks and uncertainties
which may cause the Company's actual results, performance or achievements to be
materially different from those expressed or implied by forward-looking
statements. Such factors include, among others, the uncertainties associated
with product development, the risk that clinical trials will not commence or
proceed as planned, the risks and uncertainties associated with dependence upon
the actions of our corporate, academic and other collaborators and of government
regulatory agencies, the risk that our licenses to intellectual property may be
terminated because of our failure to have satisfied performance milestones, the
risk that products that appear promising in early clinical trials do not
demonstrate efficacy in larger-scale clinical trials, the risk that we may not
be able to manufacture commercial quantities of our products, the uncertainty of
future profitability and other factors set forth more fully in the Company's
Annual Report on Form 10-K for the fiscal year ended December 31, 2003 and other
reports filed with the Securities and Exchange Commission, to which investors
are referred for further information. In particular, the Company cannot assure
you that any of its programs will result in a commercial product.
     Progenics does not have a policy of updating or revising forward-looking
statements and assumes no obligation to update any forward-looking statements
contained in this document as a result of new information or future events or
developments. Thus it should not be assumed that the Company's silence over time
means that actual events are bearing out as expressed or implied in such
forward-looking statements.

     Editor's Note:
     Additional information on Progenics available at http://www.progenics.com.

     CONTACT: Progenics Pharmaceuticals, Inc.
              Richard W. Krawiec, Ph.D., 914-789-2800
              rkrawiec@progenics.com