Bayer HealthCare Pharmaceuticals Inc. announced that its investigational compound regorafenib (BAY 73-4506) has been granted orphan drug status by the US Food and Drug Administration (FDA) for the treatment of patients with gastrointestinal stromal tumours (GIST)

Regorafenib is an investigational agent and is not approved by the FDA, the European Medicines Agency (EMA) or other Health Authorities.

"This is an important step in the overall development process for this investigational compound," said Kemal Malik, MD, head of global development and member of the Bayer HealthCare Executive Committee.

In January, Bayer began enrolling patients in a randomized, double-blind, placebo-controlled phase III study of regorafenib plus best supportive care versus placebo plus best supportive care for subjects with metastatic and/or unresectable gastrointestinal stromal tumours (GIST) whose disease has progressed despite prior treatment with at least imatinib and sunitinib (NCT01271712). The trial is estimated to enroll 170 patients, who will be randomized in a 2:1 ratio to receive either regorafenib or placebo. Subjects receiving placebo who experience disease progression may be offered open-label regorafenib treatment (cross-over option).

The primary endpoint of this trial is progression-free survival (PFS), and secondary endpoints include overall survival (OS), time to progression (TTP), disease control rate (DCR), tumour response rate (RR), duration of response (DOR), and safety. All patients will enter the Survival Follow-Up Period upon discontinuation of study treatment, during which assessment of survival status will be performed every three months.

GIST is the most common form of sarcoma involving the gastrointestinal tract. GISTs arise in the GI tract, with most primary tumours originating in the stomach or small intestine. GIST represents a potentially life-threatening malignancy if the disease has spread to other parts of the body (metastasized) or is unable to be surgically removed with curative intent. The incidence of GIST is estimated to be 11 to 20 patients per million per year. The international prevalence of GISTs is comparable to that reported in the United States. In the US, it is estimated that there are approximately 4,500-6,000 new cases of GISTs diagnosed each year, of which about 1,500 have already metastasized when they are initially found. GISTs are difficult to diagnose and are usually found incidentally when the doctor is looking for other problems.

Bayer HealthCare Pharmaceuticals Inc. is the US-based pharmaceuticals business of Bayer HealthCare LLC, a subsidiary of Bayer AG. Bayer HealthCare is one of the world's leading, innovative companies in the healthcare and medical products industry, and combines the activities of the Animal Health, Consumer Care, Diabetes Care, and Pharmaceuticals divisions.