(Bloomberg) -- Roche Holding AG said an experimental medicine helped women with a particular breast cancer mutation live longer without the disease progressing.

Patients taking the oral drug inavolisib in addition to two others fared significantly better in a late-stage study, Roche said in a statement Tuesday. 

The drug combination could offer a more effective first treatment option for women with mutations called PIK3CA, which are linked to tumor growth, disease progression and treatment resistance. The mutations are found in about 40% of hormone-positive breast cancers. 

Data on the crucial measure of overall survival are still immature at this time, Roche said, but scientists observed a positive trend. 

The Swiss drugmaker is testing inavolisib in three late-stage studies for breast cancer. If the medicine fares well and is cleared by regulators, its annual revenue could reach $532 million by 2028, according to Bloomberg estimates, placing it well behind Roche cancer blockbusters such as Perjeta and Tecentriq. 

Roche shares rose less than 1% in Zurich trading. The stock is one of the worst performers among European peers this year. 

The company, which has come under pressure to improve its pipeline with new medicines, on Monday agreed to pay as much as $3.1 billion for Carmot Therapeutics Inc., a developer of the new type of weight-loss treatments that’s sparked a pharma industry gold rush.


(Updates with revenue estimate in fifth paragraph, Roche shares in sixth)

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