Roche shares drop as oral breast cancer drug fails in trial

Shares in Roche ROG.S 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 oestrogen receptor degraders (SERD) to fight tumours that grow in response to oestrogen, accounting for up to 80% of all breast cancer cases.

The market opportunity has also attracted AstraZeneca AZN.L, which is developing rival compound camizestrant.

-Reporting by Ludwig Burger, Editing by Linda Pasquini/Reuters