Threshold Pharmaceuticals, a biotech based in South San Francisco, has earned a $20 million milestone payment from Merck for achieving a statistically significant progression free survival benefit in its 214-patient randomized controlled phase II clinical trial (404 trial).

 The trial evaluated the efficacy and safety of two doses of TH-302, a hypoxia-targeted drug, in combination with gemcitabine compared to gemcitabine alone in patients with first-line advanced pancreatic cancer. The observed safety profile was consistent with previous studies of TH-302.

"The achievement of this milestone validates the encouraging results seen in our 404 trial," said Barry Selick, Ph.D., CEO of Threshold. "We look forward to working in collaboration with Merck to rapidly determine next steps and move forward in this disease where few advances have been made."

In agreement with Merck, made in early February, Threshold was entitled to an upfront payment of $25 million, which has now been received following the termination of the applicable waiting period under the Hart-Scott-Rodino Act.