Genentech said yesterday the US Food and Drug Administration has asked for more information before it will approve the biotechnology company’s Avastin for the additional indication of breast cancer.

The request will likely delay the programme for at least a year, said Genentech, sparking a 4% decline in the firm’s share price to $78.33. The news could also be a blow to Genentech’s majority shareholder Roche, which filed for approval of Avastin (bevacizumab) as a breast cancer treatment in Europe in July.

The possibility of a delay in the programme had been anticipated, as Genentech said in its second-quarter results that the FDA had asked for more time to review the application, extending the assessment period beyond its original November 22 deadline.

This is a second blow to Genentech’s efforts to expand the indications for Avastin, one of the brightest prospects in its pipeline. In June, the company halted a trial of the drug in pancreatic cancer after it failed to boost overall survival over standard therapy.

Avastin is already a major earner for Roche and US partner Genentech from its current indication of colorectal cancer and, as well as being filed for breast cancer, is also under review for non-small cell lung cancer in the USA - with a separate submission planned for NSCLC in Europe later this year.

But the FDA’s request for more safety and efficacy data in breast cancer means Genentech will have to re-submit its application in mid-2007, with possible approval by the end of the year if the FDA takes six months to review the dossier.

The breast cancer indication would be a major boost for Avastin sales, because the doses required are higher than those approved for colorectal cancer.

The FDA has asked for a ‘substantial’ update on the safety and efficacy of Avastin in breast cancer, as well as an independent review of radiographic scans used in trials to measure progression-free survival, the endpoint which underpins the entire dossier for the drug. This will require the data to be re-collected from study centres, according to the company, as the trial was conducted by a cooperative research group sponsored by the US National Cancer Institute.

Avastin was approved for colorectal cancer in February 2004 and generated US sales for Genentech of $821 million in the first half of this year, a rise of more than 80% over the same period of 2005. Roche, which sells the drug outside the USA, booked 1.4 billion Swiss francs ($1.13bn) in sales in the first half of 2006, an advance of 119% year-on-year.

Discussing the impact of the verdict, analysts at Collins Stewart said they expected the data to stand up to further scrutiny, and that the breast cancer indication would be granted and help drives sales of Avastin to $4 billion by 2010. However, they note that their estimate is considerably less than the $7.9 billion consensus sales forecast for Avastin in 2010, which they consider "very aggressive."