Threshold Pharmaceuticals presents results of TH-302 Phase 1/2 trials in solid tumors at ASCO

Threshold Pharmaceuticals, Inc. (Nasdaq:THLD) today announced results from Phase 1/2 clinical trials in various solid tumors related to its hypoxia-activated prodrug, TH-302. The results were presented during the American Society for Clinical Oncology (ASCO) Annual Meeting being held in Chicago, IL.

Yesterday's presentation focused on two clinical trials, the 402 trial and the 403 trial. The 402 trial is a Phase 1/2, three arm, multicenter, dose escalation and dose expansion trial to determine the safety, efficacy and pharmacokinetics of TH-302 in combination with gemcitabine or docetaxel or pemetrexed in patients with advanced solid tumors. In the gemcitabine treatment arm, thirty-four patients with advanced or metastatic pancreatic cancer have had at least one evaluable post-treatment tumor assessment, including one patient (3%) with a complete response as measured by RECIST (Response Evaluation Criteria In Solid Tumors) and 8 patients (24%) with a partial response. Twenty-two patients (65%) achieved stable disease while 3 patients (9%) had progressive disease. Median progression free survival (PFS) was 6.4 months (95% CI: 4.3 months to Not Reached). Of the 34 assessed patients, 28 had elevated CA 19-9 levels at baseline and 17 of 28 (61%) had a CA19-9 reduction of greater than 50%. Hematologic toxicity was acceptable and skin and mucosal toxicities were well managed at current dose levels.

"Given the activity and safety of TH-302 in combination with gemcitabine, I am looking forward to a Phase 2 controlled trial of TH-302 in combination with gemcitabine to confirm these Phase 1/2 impressive results," said Mitesh Borad, M.D., Associate Director of Phase 1 Drug Development at the Mayo Clinic in Arizona.

These clinical results provide the basis for moving forward with a randomized, controlled Phase 2 clinical trial in 1^st line pancreatic cancer. This trial is expected to start mid-year 2010 with interim and primary endpoint results available during 2011.