Progenics Pharmaceuticals Inc. fell the most in 18 months after a study summary showed two patients died of sepsis in a trial of the company’s experimental prostate cancer treatment.
Progenics tumbled 27 percent to $4.50 at the close in New York, the biggest intraday drop since July 30, 2012. The Tarrytown, New York-based company’s stock has gained 52 percent in the past 12 months.
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 Progenics spokeswoman didn’t respond to requests for 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.