Regorafenib (Stivarga), a multi-kinase inhibitor that blocks several cancer growth enzymes, has been approved to treat advanced gastrointestinal stromal tumors (GIST) that no longer respond to other drugs and that can't be surgically removed, the FDA said.
The approval was based on a clinical study of 199 patients with nonresectable GIST that had progressed despite treatment with imatinib (Gleevec) or sunitinib (Sutent), the agency said in a statement.
In the placebo-controlled randomized trial, patients remained on either regorafenib or placebo until either the cancer progressed or the side effects became unacceptable. Placebo patients could switch to regorafenib if their cancer progressed.
The study showed that taking regorafenib rather than placebo led to an average 3.9-month delay in progression.
Serious adverse effects occurred in less than 1% of patients treated with regorafenib, the FDA noted, and included liver damage, severe bleeding, skin blistering and peeling, extreme hypertension requiring emergency care, heart attacks, and intestinal perforations.
The most common side effects were weakness and fatigue, palmar-plantar erythrodysesthesia (or hand-foot syndrome), 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.
Regorafenib is the third drug approved by the FDA to treat gastrointestinal stromal tumors, said Richard Pazdur, MD, of the agency'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," Pazdur said in a statement.
Regorafenib was also approved in September, 2012, for patients with treatment-refractory, metastatic colorectal cancer, after a 760-patient study in which it significantly improved median overall survival.
That indication included a boxed warning in the drug's prescribing information, noting that "severe and fatal liver toxicity" occurred in some regorafenib patients in the trial.
The drug, developed by Bayer, targets multiple kinase enzymes, including several related to the vascular endothelial growth factor (VEGF) receptor and others associated with KIT, RET, and the platelet-derived growth factor and fibroblast growth factor receptors.
The National Cancer Institute estimates there are 3,300 to 6,000 new cases of GIST annually in the U.S.