Threshold Pharmaceuticals, Inc. (Nasdaq: THLD), today announced the initiation of a Phase 1/2 dose escalation clinical trial of TH-302 in combination with sunitinib in patients with advanced renal cell carcinoma (RCC), gastrointestinal stromal tumor (GIST) and pancreatic neuroendocrine tumor (PNET). TH-302 is a proprietary tumor selective Hypoxia-Activated Prodrug (HAP) that specifically targets tumor hypoxia. Sunitinib, marketed by Pfizer under the brand name Sutent ®, is an oral, small molecule angiogenesis inhibitor that is currently approved for the treatment of RCC, GIST and PNET.
"The treatment of solid tumors continues to be a difficult therapeutic challenge. While the introduction of anti-angiogenics has enabled significant efficacy improvements, most patients ultimately relapse. There is now increasing evidence that anti-angiogenics induce tumor hypoxia. Therefore, adding TH-302 to an agent like sunitinib holds the promise of broader treatment coverage of the tumor than would be achieved by either agent alone. Indeed, this underlying scientific rationale combined with Threshold’s preclinical work in RCC models drove the initiation of this study," said Dr. Alexander Starodub, M.D., Indiana University Health Goshen Center for Cancer Care and principal investigator for the trial. "I am hopeful that TH-302 may prove to be an effective new agent for the treatment of renal cell carcinoma."
Clinical Trial Design
Approximately 34 patients with advanced RCC, GIST or PNET are planned to enroll in the clinical trial at Indiana University Health Goshen Cancer Center. The dose escalation phase of the trial will enroll up to 24 patients. The primary objective of the dose escalation component of the study is to establish the maximum tolerated dose (MTD) and dose limiting toxicities of TH-302 in combination with sunitinib. Patients for whom no effective therapy is available or for whom monotherapy with sunitinib is considered standard therapy are eligible for the trial.Once the MTD has been reached, an additional 10 patients with advanced RCC will be enrolled at the MTD. The primary objective of the dose expansion component of the study is to make a preliminary assessment of the efficacy of TH-302 in combination with sunitinib as measured by the overall tumor response rate and progression-free survival. Tumor response will be evaluated at baseline and every twelve weeks using the Response Evaluation Criteria In Solid Tumors (RECIST).