Bayer’s follicular lymphoma treatment copanlisib could be less than two months away from gaining US approval after the FDA awarded it priority review.

The firm is seeking approval for its intravenous PI3K inhibitor as a third-line treatment for patients with relapsed or refractory FL, the most common type of non-Hodgkin's lymphoma (NHL).

The bid is based on results from Bayer’s Phase II CHRONOS-1 trial, which showed  copanlisib achieved an objective response rate (ORR) of 59% with durable responses.

Carsten Brunn, head of Bayer Pharmaceuticals, Americas Region, said: "With this milestone, we are one step closer to making copanlisib available in the US to the community of doctors and patients facing a very difficult-to-treat disease. We look forward to continuing to work with the FDA throughout the review process."

If approved Copanlisib, which also has orphan and fast-track designations from the FDA, would compete with the likes of Zydelig, a P13K inhibitor from Gilead that is already approved for FL and chronic lymphocytic leukaemia.