Threshold Pharmaceuticals reports preliminary results from Phase I cancer trial

Preliminary results from 22 patients were reported in an ongoing Phase I clinical trial evaluating the safety and preliminary efficacy of TH-302 in patients with advanced solid tumors.

Preliminary efficacy signals have been observed in two patients enrolled in the ongoing Phase I trial. As previously reported, one patient with refractory small cell lung cancer metastatic to the liver had a partial response, as judged by Recist, at their initial response assessment. The patient had received two cycles of TH-302 at 480mg/m2 and discontinued from study after treatment delay unrelated to therapy, and disease progression.

More recently, one patient with melanoma metastatic to the lung and liver had a Recist criteria partial response after two cycles of TH-302 at 670mg/m2 and is continuing on study. The confirmation of this response will be contingent upon a subsequent assessment and there can be no assurance that that assessment will confirm the initial findings.

The first dose limiting toxicities for TH-302 were reported in the 670mg/m2 cohort. One patient treated at 670mg/m2 developed grade 3 herpes simplex virus perianal and rectal ulcers that were considered related to study drug. A second patient treated at 670 mg/m2 developed grade 3 dehydration due to oral mucositis. Doses below 670mg/m2 are now being investigated to determine the maximum tolerated dose.