BIOWIRE

Progenics Pharmaceuticals, Inc. (NASDAQ: PGNX) today announced the
expansion of its collaboration with Seattle Genetics, Inc. (NASDAQ:
SGEN) to include activities intended to accelerate the manufacture and
development of Progenics' prostate-specific membrane antigen (PSMA)
antibody-drug conjugate (ADC). Under the expanded collaboration,
Seattle Genetics will develop and optimize certain methods suitable for
manufacturing and testing PSMA ADC to support studies in humans. The
new agreement is designed to accelerate development of this product by
leveraging Seattle Genetics' prior experience in ADC process
development and testing. Progenics is responsible for fees and
milestone payments in addition to those already provided under the
parties' existing collaborative agreement established in June 2005.

"We are committed to developing PSMA-based immunotherapies for prostate
cancer that are potentially less toxic and more active than existing
treatments," said Paul J. Maddon, M.D., Ph.D., Progenics' Founder,
Chief Executive Officer and Chief Science Officer. "Prostate cancer
patients with metastatic disease have the greatest unmet medical need,
and we intend to initiate phase 1 clinical studies in this setting
during 2007 with our fully human antibody-drug conjugate. Having
acquired full rights to our PSMA antibody-drug conjugate program in
April, core teams from our research and development, manufacturing,
clinical and regulatory areas are working to expedite the development
of this promising new therapy."

Potent Anti-Tumor Activity

Progenics also announced today that findings on its PSMA ADC program
were published in the current issue of Clinical Cancer Research (volume
12, issue 8). Top line results from this study were originally reported
in a Progenics press release during September 2005. In a
well-recognized mouse model of human prostate cancer, PSMA ADC
significantly prolonged overall survival up to nine-fold as compared to
untreated animals (p=0.0018, log-rank test, two-sided). Remarkably,
established tumors in two of the five animals treated at the highest
dose were eradicated and remained undetectable over 500 days through
the completion of the study. No overt toxicity was observed in any of
the treated animals.

PSMA

PSMA is a protein abundantly expressed on the surface of prostate
cancer cells, with an increased expression in high-grade cancers,
metastatic disease and hormone-refractory prostate cancer. In contrast
to other prostate markers such as prostate-specific antigen (PSA),
prostatic acid phosphatase (PAP) and prostate secretory protein, PSMA
is a membrane glycoprotein that is expressed at the cell surface and
not secreted. PSMA is also present at high levels on the newly formed
blood vessels, or neovasculature, needed for the growth and survival of
many solid tumors; however, PSMA has limited expression on normal
tissues other than prostate. This unique expression pattern makes PSMA
an attractive target for cancer immunotherapy.

PSMA ADC

PSMA ADC is a fully human monoclonal antibody to PSMA linked to a
derivative of auristatin, a highly potent cytotoxic drug, utilizing
Seattle Genetics' proprietary ADC technology. The monoclonal antibody
portion binds PSMA with high affinity and specificity, thereby
targeting the cytotoxic drug to cancer cells. After binding its target,
PSMA ADC rapidly enters the cancer cell and releases the drug payload.
Once released from the antibody, the drug destroys the cancer cell by
disrupting the cellular "backbone" required for growth and division.
PSMA ADC is designed to be stable in blood so as to minimize toxicity
to normal cells and tissues that do not express PSMA.

Prostate Cancer

Prostate cancer is the most common form of cancer affecting men in the
United States and is the second leading cause of cancer deaths among
men each year. The American Cancer Society estimated that 232,090 new
cases of prostate cancer were diagnosed and that 30,350 men died from
the disease during 2005 in the United States.