Bayer has been boosted by the news that the US Food and Drug Administration have granted a priority review to the firm's investigational colorectal cancer treatment regorafenib.

The move will see the regulator evaluate the oral multi-kinase inhibitor in six months rather than the usual ten-month timeframe. Bayer is looking to get approval for regorafenib for the treatment of patients with metastatic colorectal cancer whose disease has progressed after approved standard therapies.

The submission was based upon data from the Phase III CORRECT trial which showed that regorafenib plus best supportive care significantly improved both overall and progression-free survival, compared to placebo. That study was unblinded and patients on the placebo arm were offered treatment with regorafenib.

The drug was at the centre of a row between Bayer and partner Onyx Pharmaceuticals which was settled in October 2011. Before then, in May 2009, Onyx sued over the rights to the drug, claiming it is a variant of the two firms' Nexavar (sorafenib), while Bayer had always insisted that regorafenib is not covered by a collaboration the companies signed in 1994.

The settlement recognised that regorafenib is a Bayer compound, while Onyx will receive a 20% royalty. The US biotech will not have to pay any development and commercialisation costs and has a co-promotion option in the USA.