Bayer and Norway's Algeta have been boosted by the news that their investigational prostate cancer therapy Alpharadin has been granted fast-track designation by US regulators.

Specifically, the Food and Drug Administration has fast-tracked Alpharadin for the treatment of castration-resistant (hormone-refractory) prostate cancer in patients with bone metastases. The treatment is the first in a new class of 'alpha-pharmaceuticals' which is based on radium-223, a drug containing an alpha-particle emitting nuclide.

The news comes a couple of months after Bayer and Algeta stopped a late-stage trial of Alpharadin on data which showed that it significantly improved overall survival - 14.0 months versus 11.2 months for placebo. Algeta chief executive Andrew Kay said the fast-track "represents an important step towards Alpharadin filing, which we anticipate mid-2012, ahead of previous expectations".

Analysts believe Alpharadin will be a blockbuster and the news from across the Atlantic has gone down well with investors. At 10.10am (UK time), Algeta's shares had climbed 10.6%, while Bayer stock was up about 2%.