Exelixis has begun two investigator-sponsored trials of cabozantinib, which simultaneously targets MET, VEGFR2 and RET.

A Phase 2 trial of cabozantinib is being conducted in non-small cell lung cancer (NSCLC) patients who have tested positive for gene fusions that activate RET.

A pilot Phase 1 trial of cabozantinib is being conducted in patients with relapsed or refractory multiple myeloma, a disease for which there is evidence of MET’s role in pathogenesis.

Exelixis president and chief executive officer Michael Morrissey said the company’s IST Program is a critical component of the strategy to evaluate cabozantinib in a broad array of indications while focusing its internal efforts and resources on medullary thyroid cancer and prostate cancer

"We are pleased to support leading oncologists such as Dr. Rizvi and Dr. Mahindra as they leverage cabozantinib’s target-inhibition profile to address specific cancer indications in which these targets are believed to play a key role," Morrissey added.

"An IST with cabozantinib, a potent inhibitor of RET that has shown strong clinical activity in another RET-driven cancer, is a logical next step in advancing new approaches to treat the disease."

The Phase 2 NSCLC trial is designed to enrol 25 patients with KIF5B/RET or related variant RET fusions in their tumours, who will receive a daily 60mg dose of cabozantinib administered orally.

The overall response rate is the primary endpoint of the trial. Secondary endpoints include progression-free survival, overall survival, and safety.

The study will also determine the frequency of KIF5B/RET and related variant RET fusions in patients whose tumours are negative for previously identified oncogenic activating mutations or translocations.

The Phase 1 multiple myeloma trial is designed to assess the safety, tolerability, and preliminary activity of cabozantinib in patients with relapsed or refractory myeloma with bone disease.

The first cohort of patients will receive 40mg of cabozantinib daily. A second cohort of patients will receive either 20mg or 60mg of cabozantinib, administered daily, depending on the safety in the first cohort.