Bayer has filed for approval of its investigational cancer drug candidate regorafenib as a treatment for gastrointestinal stromal tumours (GIST) in the US.
The application comes a few weeks after the pharma company filed its first marketing applications for the oral multi-kinase inhibitor for metastatic colorectal cancer in the US and Europe, with the FDA granting it a priority review.
The drug is one of four in Bayer's late-stage pipeline that are tipped to have blockbuster sales potential, and analysts have suggested that GIST alone could be a market worth $500m for the drug.
The latest filing with the FDA is seeking approval for regorafenib in metastatic GIST, or cases which are not treatable with surgery, in patients whose disease has progress despite treatment with other kinase inhibitors.
GIST - a rare type of sarcoma which occurs most often in the stomach wall - is typically treated with Novartis' Glivec/Gleevec (imatinib) in the first instance and with Pfizer's Sutent (sunitinib) as a second-line option.
Novartis recently stopped a phase III trial of another candidate GIST treatment called Tasigna (nilotinib) after data indicated that the drug was unlikely to demonstrate superiority in progression-free survival over Glivec.
Bayer filed for approval of regorafenib in GIST on the back of the 199-patient GRID study, which found that regorafenib significantly improved progression-free survival (PFS) compared to placebo. The median PFS was 4.8 months in the regorafenib arm versus 0.9 months in the placebo arm.
"The submission of regorafenib for the treatment of GIST brings us one step closer to meeting a significant medical need for patients with this aggressive disease," said Bayer's head of global development Kemal Malik.
Regorafenib was at the heart of a dispute between Bayer and partner Onyx Pharmaceuticals, which filed a lawsuit against the German drugmaker in 2009 claiming rights to the drug under the terms of a collaboration between the firms which led to the development of kidney and liver cancer drug Nexavar (sorafenib).
The suit was settled last year after the two companies agreed that regorafenib is a Bayer compound but Onyx would receive a 20 per cent royalty on sales.