Threshold Reports Phase 1/2 Clinical Trial Of TH-302

The clinical 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. The results of the trial discussed only those patients who were treated for gastrointestinal cancer, which included but were not limited to, cancers of the pancreas, colon and bile duct.

Out of 43 patients enrolled with gastrointestinal cancer, 38 have been assessed for response. Of the 38 patients assessed, 12 (32%) had a RECIST criteria partial response (PR), 22 (58%) achieved stable disease (SD) and four patients (10%) had progressive disease (PD). The partial response included both confirmed and unconfirmed partial responses. In a confirmed partial response, partial response was maintained through a subsequent response assessment at least 28 days later. In an unconfirmed partial response, the partial response was reported at one assessment but was not maintained in a subsequent response assessment or has yet to be assessed after the initial assessment in response.

In the presentation, the majority of the patients had first-line pancreatic cancer, 18 of whom received TH-302 plus gemcitabine, three of whom received TH-302 plus pemetrexed and one who received TH-302 plus docetaxel. Across the 22 patients with pancreatic cancer, 20 were assessed for response and 19 (95%) achieved stable disease or better. For these 20 patients, the mean time on study was over 3.5 months and nine patients continue to receive therapy on study. The TH-302 maximum tolerated dose (MTD) continues under investigation with the dose cohort currently being expanded at 340mg/m2.

John Curd, president and chief medical officer of Threshold, said: “While limited in number, the results we have seen in first-line pancreatic cancer are notable as compared to historical standards. Historically, the response rates in first-line pancreatic cancer with gemcitabine have been less than ten percent. We believe that the current safety and activity data supports an additional study of TH-302 in combination with full dose gemcitabine to determine if TH-302 adds clinical benefit to patients fighting pancreatic cancer.”