The FDA has expanded the approved use of regorafenib (Stivarga) to treat patients with metastatic or unresectable gastrointestinal stromal tumors (GIST) that no longer respond to treatment with imatinib (Gleevec) or sunitinib (Sutent). Regorafenib, a multikinase inhibitor, blocks several enzymes that promote cancer growth.
“[This] is the third drug approved by the FDA to treat gastrointestinal stromal tumors,” said Richard
Pazdur, MD, Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “It provides an important new treatment option for patients with GIST in which other approved drugs are no longer effective.”
Regorafenib was reviewed under the FDA’s priority review program, which provides an expedited 6-month review for drugs that may provide safe and effective therapy when no satisfactory alternative therapy exists, or offer significant improvement compared to marketed products. The drug was also granted orphan product designation because it is intended to treat a rare disease.
The safety and effectiveness of regorafenib for this use were evaluated in a clinical study of 199 patients with unresectable GIST that had progressed after treatment with imatinib or sunitinib. Patients were randomly assigned to receive either regorafenib or a placebo. All patients received optimal supportive care.
Patients in the study took regorafenib or placebo until disease progression or unacceptable toxicity. Results showed an average improvement of 3.9 months in patients who took regorafenib compared with patients who were given placebo. Patients who received the placebo were given the opportunity to switch to regorafenib when their cancer progressed.
The most common side effects reported in patients treated with regorafenib were weakness and fatigue, palmar-plantar erythrodysesthesia, diarrhea, loss of appetite, high blood pressure, mouth sores, infection, changes in voice volume or quality, pain, weight loss, stomach pain, rash, fever, and nausea.
Serious side effects, which occurred in less than 1% of patients, were liver damage, severe bleeding, blistering and peeling of skin, very high blood pressures requiring emergency treatment, heart attacks, and perforations in the intestines.
Regorafenib was approved in September 2012 to treat colorectal cancer. It is marketed by Bayer HealthCare Pharmaceuticals. ■