Regorafenib active in metastatic GI stromal tumors

(HealthDay) -- Regorafenib, an inhibitor of multiple cancer-associated kinases, is active in patients with metastatic gastrointestinal stromal tumors (GIST) who have failed to respond to imatinib and sunitinib, according to a study published online May 21 in the Journal of Clinical Oncology.

Suzanne George, M.D., of the Dana-Farber Cancer Institute in Boston, and colleagues conducted a multicenter, single-stage phase II trial of oral regorafenib, 160 mg/day, in 34 patients with advanced GIST after failure of imatinib and sunitinib. The clinical benefit rate (CBR), defined as objective response (partial response and stable disease ≥16 weeks), was the primary study end point.

The researchers found that the CBR was 79 percent for the 33 patients who had received at least two cycles of regorafenib. Of these, 22 patients exhibited stable disease for 16 weeks or longer, and four patients achieved a partial response. Median progression-free survival (PFS) was 10 months. Hypertension and hand-foot-skin reaction were the most commonly observed grade 3 toxicities.

"In summary, regorafenib is a novel orally available multikinase inhibitor with notable activity in patients with advanced GIST after objective failure of both prior imatinib and sunitinib," the authors write. "The median PFS >10 months observed in these heavily pretreated patients supports the hypothesis that regorafenib may be a uniquely active agent in the management of GIST after treatment with imatinib and sunitinib."

Several authors disclosed financial ties to drug companies, including Bayer HealthCare Pharmaceuticals, which provided funding and the study drug.

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