January 02, 2013
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Regorafenib extends progression-free survival in patients with gastrointestinal stromal tumors

Patients with gastrointestinal stromal tumors who had been unresponsive to prior treatment experienced longer progression-free survival with regorafenib than placebo recipients in a recent study.

In the multicenter, international phase 3 trial, researchers randomly assigned 199 patients with metastatic or unresectable gastrointestinal stromal tumors (GIST) to receive either 160 mg regorafenib orally once a day (n=133) or placebo (n=66) for the first 3 weeks of every 4-week cycle, in addition to best supportive care, from Jan. 4 through Aug. 18, 2011 with a data cutoff of Jan. 26, 2012. All participants had failed previous treatment with imatinib and sunitinib.

Researchers concluded analysis after 144 progression-free survival (PFS) events occurred, including 81 among treated patients (61%) and 63 in the placebo group (95%). Patients taking regorafenib had a median treatment duration of 22.9 weeks, compared with 7 weeks among placebo recipients. Median PFS was 4.8 months (range 1.4-9.2 months) for treated patients and 0.9 months (0.9-1.8 months) for those receiving placebo (HR=0.27; 95% CI, 0.19-0.39 for those receiving regorafenib). PFS was 60% among treated patients and 11% in the placebo group at 3 months; and 60% and 0%, respectively, at 6 months.

No significant difference was observed regarding overall survival (HR=0.77; 95% CI, 0.42-1.41 for treated patients vs. placebo recipients). Investigators indicated overall response rates of 4.5% for regorafenib and 1.5% for placebo, with disease control rates of 52.6% and 9.1%, respectively (P<.0001).

Treatment-related adverse events occurred in 98% of regorafenib patients and 68% of placebo patients. Commonly reported events of grade 3 severity or higher in the treated group included hypertension (23% of cases), hand-foot skin reaction (20%) and diarrhea (5%). Rates of discontinuation because of adverse events were similar between groups (6% among treated patients compared with 8%).

“When added to best supportive care, regorafenib significantly improves PFS in a population of patients with GIST with progressive disease after failure of all approved previous therapies, compared with matching placebo,” the researchers concluded. “Future studies … will investigate further the molecular mechanisms by which the treatment can induce disease control after failure of both imatinib and sunitinib.”

Disclosure: See the study for a full list of relevant disclosures.