Roche this morning said it is seeking European approval to expand the indications for its blockbuster cancer drug Avastin (bevacizumab) to include patients with advanced breast cancer who are as-yet untreated. A first line label could significantly broaden the drug's market potential and follows positive data from a late-stage study showing Avastin doubles the time to disease progression.

Avastin is already a major earner for Roche and US partner Genentech, and is on the market for treating colorectal cancer, as well as being filed for both breast cancer and non-small cell lung cancer in the USA - with a separate submission planned for NSCLC in Europe later this year.

This latest dossier is based on data from the so-called E2100 study, which evaluated Avastin in combination with Bristol-Myers Squibb's Taxol (paclitaxel), or Taxol alone, among 722 previously-untreated women with breast cancer. Results demonstrated a median progression-free survival of more than one year, while patients given Taxol alone experienced disease-free survival for six months. Overall, patients receiving the combination therapy had a 52% reduction in the risk of death or disease progression versus those given the gold-standard therapy.

The Swiss drugmaker recorded sales of $1.3 billion for Avastin in 2005, while Genentech said it booked $1.1 billion from the product, despite recent wobbles in pancreatic cancer and a trial suspension in ovarian cancer and colon cancer (the latter has since been re-started). None of these concerns seem to have dented Avastin's potential, and analysts believe it could generate peak sales in the region of $4 billion.

A decision on Avastin's use in advanced breast cancer could come as soon as November in the USA.