Threshold Pharma is to go ahead with Phase 3 clinical trials of its only drug, TH-302, despite recent Phase 2 trials failing to show statistically significant improvement in overall survival. These findings spooked investors in the biotechnology company and the shares dropped as much as a third. However, some analysts believe that these investors have overreacted, because overall survival was not the primary endpoint of the Phase 2 studies.

Th-302 is an investigational hypoxia-targeted drug for patients with advanced pancreatic cancer. The Phase 2 findings indicated that patients treated with Gemzar (Eli Lilly’s chemotherapy drug gemcitabine) alone had a median overall survival of 6.9 months, compared with 9.2 months for patients treated with 340mg of TH-302 plus gemcitabine. This increase is not seen as statistically significant.

TH-302 also continues to demonstrate a safety profile consistent with what was previously reported at the 2012 annual meeting of the American Association for Cancer Research.

“We are pleased with the overall consistency of results from this study demonstrating activity of TH-302 and, as a consequence, a randomized Phase 3 trial of TH-302 in patients with advanced first-line pancreatic cancer is planned to be initiated together with our partner Merck KGaA. We are grateful to the clinical investigators and patients who have participated in our studies of TH-302 and would like to acknowledge their important contributions to advancing the development of novel therapies for pancreatic cancer.”

Barry Selick, Ph.D., Chief Executive Officer of Threshold.

Threshold Pharma’s TH-302 is also being tested in a further 11 clinical trials at the moment. If the FDA approves it in conjunction with Gemzar for pancreatic cancer, TH-302 will join the current crowded market, which includes Peregrine Pharmaceutical’s bavituximab and Celgene’s Abraxane.