Shares in drugmaker Roche Holding fell 4% in Swiss trading after a panel of experts recommended that Avastin no longer be used to treat breast cancer.
The Swiss-based firm shares plunged to 137.20 Swiss francs (£85.29) during trading in Zurich.
It comes after a US Food and Drug Administration panel said new studies had showed no apparent benefit from the drug.
They voted 12-1 to remove approval for the use of Avastin along with chemotherapy to treat breast cancer.
The negative vote was the first major setback for a drug that has approvals for colon, lung, kidney, brain and other forms of cancer. The panel’s ruling only pertains to Avastin’s use in breast cancer.
Roche scientists argued that patients taking Avastin experienced improved quality of life as tumour growth and other symptoms are delayed – but panelists were not convinced. They, in turn, cited little benefit to patients despite toxicity risks.
Medical societies and hospitals tend to follow FDA guidance, influencing prescribing patterns for thousands of US physicians.
Avastin was Roche’s top-selling cancer drug last year with sales of $5.9 billion.
Copyright Press Association 2010