Roche said on Monday that the US health regulator approved its Avastin drug as a treatment for women with ovarian cancer that is resistant to platinum-containing chemotherapy.

Avastin, which is already approved in Europe to treat advanced stages of breast cancer, colorectal cancer, non-small cell lung cancer, kidney cancer and ovarian cancer, was Roche's biggest seller last year with sales of 6.25 billion Swiss francs (6.53 billion US dollar).