In another setback to Swiss pharmaceutical company Roche Holding, as it tries to extend the use of Avastin, its blockbuster cancer drug into new areas, clinical trials suggest it does not increase the survival rates of men with late-stage prostate cancer.

Announcing its failure Friday, Roche suffered a similar disappointment last month with Avastin in gastric cancer, though it was successful in ovarian cancer. The drug already used for treating colon, breast, lung and kidney cancers, works by starving tumours of blood.

Its 2009 annual global sales topped 6.2 billion Swiss francs (about $5.8 billion).

The news caused shares in Roche to fall 2.2%, as investors revised expectations for Avastin, which analysts had been watching closely with many believing in a few years time, it could become the world’s biggest-selling pharmaceutical.

The company had suggested before the trial failure of Avastin for prostate cancer that the drug could boost annual sales anywhere between 500 million Swiss francs ($464.3 million) to 1 billion.

Estimates that likely to be revised down from 9.8 billion francs to nearer 9 billion for the 2014 sales forecast, given that Avastin, while unsuccessful in treating prostrate cancer has done well as a treatment for ovarian cancer.

The drug is a flagship product for the world’s largest maker of cancer drugs, as it has the potential for market expansion and moving into new types of cancer treatment.

Further details on recent clinical trials with Avastin will be presented at the 2010 American Society of Clinical Oncology (ASCO) annual meeting later this year.

Prostate cancer is the second most commonly diagnosed cancer in men worldwide after lung cancer, with one third of the men diagnosed will die from it.