Bayer HealthCare has initiated patient enrolment for an international Phase III trial evaluating investigational regorafenib (BAY 73-4506) as a treatment for metastatic or unresectable gastrointestinal stromal tumours (GIST).

The randomised, double-blind, placebo-controlled, multi-centre and crossover study will enrol approximately 170 patients whose cancer has progressed after initial treatment with at least imatinib and sunitinib as prior treatment regimens.

Patients will be randomised in 2:1 ratio to receive a 160mg dose of regorafenib or a placebo. Those who are given the placebo and experience disease progression will be allowed to switch to open-label regorafenib treatment, as per the crossover option.

The primary endpoint of the trial will be progression-free survival. Secondary endpoints include overall survival, time to progression, disease control rate, tumour response rate, duration of response and safety.

Kemal Malik, head of global development at Bayer Schering Pharma, said that there are limited treatment options available for patients whose GIST tumours have progressed after imatinib and sunitinib.

“Bayer is committed to its ongoing efforts to improve the lives of people with cancer, and the initiation of a Phase III clinical trial for regorafenib is a critical step towards a potential new treatment option for GIST patients,” Malik added.

Regorafenib is an oral multi-kinase inhibitor, which targets angiogenic, stromal and oncogenic receptor tyrosine kinases.