Exhibit 99.1

Progenics Announces Achievement of Enrollment Target in Phase 2 Clinical Trial
of Methylnaltrexone for Post-Operative Ileus

    TARRYTOWN, N.Y.--(BUSINESS WIRE)--Oct. 7, 2004--Progenics
Pharmaceuticals, Inc. (Nasdaq: PGNX) today announced that the target
enrollment has been reached in the phase 2 study of its
investigational drug, methylnaltrexone (MNTX) for the treatment of
post-operative ileus (POI). The Company expects to announce top-line
results from the 60-patient, multi-center, double-blind, randomized,
placebo-controlled study in early 2005. Each year in the U.S.,
approximately four-million patients undergo surgeries which place them
at high risk for developing ileus, a paralysis of the gastrointestinal
tract. Ileus is a leading cause of prolonged hospital stay in these
cases.
    "In this proof-of-concept study, we have enrolled a population of
patients who typically are at high risk for prolonged ileus," said
Robert J. Israel, M.D., Progenics' Senior Vice President of Medical
Affairs. "Specifically, all of the patients on the study underwent
segmental colectomies, a removal of a portion of their colon, usually
for cancer. This trial was designed to evaluate the clinical utility
of MNTX to restore promptly gastrointestinal function and to shorten
hospital stay. There is currently no approved therapy for POI, and we
believe that MNTX may improve the resolution of ileus."
    Progenics is pursuing three different indications for MNTX which
correspond to three dosage forms: In advanced medical illness, MNTX is
being studied in two, pivotal phase 3 clinical trials in
opioid-induced constipation using the subcutaneous form. MNTX is being
studied for the treatment of post-operative ileus by intravenous
dosage, and oral MNTX 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. MNTX
is also being studied for the treatment of post-operative ileus and
relief of opioid-induced constipation in patients with chronic pain.
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 ProVax, a novel prophylactic HIV vaccine. The
Company, in collaboration with Cytogen Corporation, 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 October 7, 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 is available at
http://www.progenics.com

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