Exelixis to start cabozantinib Phase 2 IST study

The multi-center, open label, single arm trial will enroll 50 women with hormone receptor-positive breast cancer that has metastasized to the bone and whose disease has progressed after initial treatment for metastatic disease.

The primary endpoint of the trial is bone scan response rate determined by local institutions and by an independent radiology facility.

Secondary endpoints are objective response rate, overall survival, progression-free survival, effects of cabozantinib on tumor markers and biochemical markers of bone turnover, skeletal-related events, and positron emission tomography (PET) response rate.

The identification of surrogate biomarkers associated with the clinical activity of cabozantinib is included as an exploratory endpoint.

Exelixis president and CEO Michael Morrissey said they believe that this trial and the 306 trial together should provide important further insights into the compound’s activity on bone metastases, and build a foundation for further clinical inquiry.