Bayer is celebrating after the US Food and Drug Administration gave the green light to Stivarga for the treatment of gastrointestinal stromal tumours.

The agency has approved Stivarga (regorafenib) tablets to treat patients with GIST who have been previously treated with Novartis' Glivec/Gleevec (imatinib) and Pfizer's Sutent (sunitinib). The approval is based on a Phase III study that demonstrated a statistically significant improvement in progression-free survival (PFS) compared to placebo (4.8 months versus 0.9 months) in patients with GIST whose disease had progressed after treatment with Glivec and Sutent.

Stivarga is already approved by the FDA for the treatment of patients with metastatic colorectal cancer (mCRC) who have been previously treated with fluoropyrimidine-, oxaliplatin- and irinotecan-based chemotherapy, an anti-VEGF therapy, and, if KRAS wild type, an anti-EGFR therapy. Kemal Malik, head of global development at Bayer Healthcare, said that "we look forward to being able to offer benefit to patients with this rare but aggressive disease who have no other approved treatment options".

The latest approval is also good news for Onyx Pharmaceuticals which jointly promotes regorafenib in the USA. After a two-year dispute over ownership of the compound, a settlement was reached in October 2011 which stated that it is a Bayer drug, while Onyx will receive royalties on global sales.

Priority review in Japan

Bayer also announced that the Japanese Ministry of Health, Labour and Welfare has granted priority review to regorafenib for GIST. The drug has also been filed in Japan for colorectal cancer and was given priority review in this indication in August 2012.