The U.S. Food and Drug Administration (FDA) has granted orphan drug status for the investigational compound regorafenib (BAY 73-4506). The new compound will be used for the treatment of patients with gastrointestinal stromal tumors (GIST) and is under developed by Bayer HealthCare Pharmaceuticals Inc.

GIST is the most common form of sarcoma involving the gastrointestinal tract. GISTs arise in the GI tract, with most primary tumors 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 U.S., 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.

Orphan Drug Status
Regorafenib is an oral multi-kinase inhibitor which targets angiogenic, stromal and oncogenic receptor tyrosine kinase (RTK). Regorafenib shows anti-angiogenic activity due to its dual targeted VEGFR2-TIE2 tyrosine kinase inhibition. The drug is an investigational agent and is not approved by the FDA, the European Medicines Agency (EMA) or other Health Authorities.

Under the terms of the U.S. Orphan Drugs Act (ODA) the FDA encourages the development of drugs involved in the diagnosis, prevention or treatment of a medical condition affecting fewer than 200,000 people in the country. The designation grants U.S. market exclusivity to a drug for a particular indication for a seven-year period if the sponsor complies with certain FDA specifications. Additional incentives for the sponsor include tax credits related to clinical trial expenses and a possible exemption from the FDA-user fee. The designation does not shorten the duration of the regulatory review and approval process.

Advertisement #3

“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.

Randomized Trial
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 tumors (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 study is composed of 3 periods: A Screening Period, a Treatment Period, and a Survival Follow up Period. Subjects randomized to be treated with regorafenib will receive 160 mg po od for 3 weeks of every 4 week (28 day) cycle (ie, 3 weeks on/1 week off). In addition subjects will receive best supportive care which excludes any disease specific anti cancer therapy such as any kinase inhibitor, chemotherapy, radiation therapy, or surgery.

Tumor assessment will be every 4 weeks for the first 3 months, every 6 weeks for the next 3 months (through month 6), and every 8 weeks until the end of treatment, or more frequently if clinically indicated. Tumor assessments include ‘CT or MRI and will be performed until tumor progression is seen in a central radiology review.

Subjects receiving placebo who experience disease progression may be offered active treatment. Subjects who experience progression during regorafenib treatment may continue open label treatment. All subjects will enter the Survival Follow-up Period upon discontinuation of randomized study treatment.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), tumor 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.

For information:
Study of Regorafenib as a 3rd-line or Greater Treatment for Gastrointestinal Stromal Tumors (GIST) (GRID) NCT01271712.

Advertisement #5