FRANKFURT - Shares in Roche dropped more than 5 % on Monday as the Swiss drugmaker failed to show that its promising drug candidate giredestrant against a common form of breast cancer can help newly diagnosed patients.
At 0846 GMT, the stock was down 5.1 % at its lowest in about a month.
A phase III trial did not provide reliable evidence that the drug's use in combination with Pfizer's Ibrance as a first treatment slows disease progression when compared with a standard hormonal therapy plus Ibrance, Roche said in a statement.
That marked a reversal of fortunes for the oral compound.
The Roche pill last year cut the risk of tumour recurrence in breast-cancer patients who had received the established initial treatment in a late-stage trial, boosting Roche's shares.
The giredestrant pill belongs to a drug class known as oral selective oaestrogen receptor degraders (SERD) to fight tumours that grow in response to oaestrogen, accounting for up to 80 % of all breast cancer cases.
The market opportunity has also attracted AstraZeneca , which is developing rival compound camisestrant.
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