Progenics Falls After Two Deaths in Cancer Drug Trial

Progenics Pharmaceuticals Inc. (PGNX) fell the most in 14 months after a study summary showed two patients died of sepsis in a trial of the company’s experimental prostate cancer treatment.

Progenics tumbled 19 percent to $5.04 at 12:11 p.m. New York time, after losing as much as 20 percent for its biggest intraday drop since November 2012. The Tarrytown, New York-based company’s stock had doubled in the 12 months through yesterday.

The targeted chemotherapy treatment for prostate cancer is designed to act as a “Trojan horse,” remaining stable in the blood then releasing toxins once inside tumor cells, according to company’s website. The study abstract appears to show that even at a lower dose of the drug, PSMA-ADC, patients could experience life-threatening levels of toxicity, said Brian Klein, an analyst at New York-based Stifel Nicolaus & Co.

The deaths suggest that the drug has “a major impact on the immune system,” Klein said in a phone interview.

Progenics is scheduled to discuss the study tomorrow at the Genitourinary Cancers Symposium in San Francisco. A summary was posted on the symposium’s website, revealing the two deaths. A spokeswoman for Progenics didn’t immediately respond to a request to comment on the findings.

PSMA-ADC is a so-called antibody-drug conjugate, which uses an antibody to find and bind with a protein on the surface of prostate cancer cells then deliver a cancer-killing chemical. Sepsis is often the result of a blood or tissue infection that causes the immune system to attack the body in a way that can typically lead to multiple organ failure and death.

The drug appears to offer “little benefit versus the apparent toxicity,” Klein said in a research note to clients.

“We believe this compound does not demonstrate the necessary characteristics to move forward into late stage testing,” Klein, who has a hold rating on Progenics, said in the note.

To contact the reporter on this story: Caroline Chen in New York at cchen509@bloomberg.net

To contact the editor responsible for this story: Reg Gale at rgale5@bloomberg.net

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