ZURICH (Reuters) – Swiss pharma group Roche’s drug Perjeta (pertuzumab) significantly extended the lives of women with HER2-positive breast cancer compared to a placebo, according to new data from a late-stage study presented on Saturday.

The detailed data presented at the San Antonio Breast Cancer Symposium found that the risk of death was reduced by 34% in women treated with a combination treatment of the drugs Perjeta and Herceptin plus chemotherapy compared to women treated with Herceptin, chemotherapy and a placebo, Roche said.

Perjeta was granted approval by U.S. health regulators in June. Roche is awaiting a decision from European regulators.

Roche is hoping that the Perjeta combination will become the standard treatment HER2-positive breast cancer, which makes up about a quarter of all breast cancers.

At the time of the analysis, median overall survival had not yet been reached in people receiving the Perjeta combination, Roche said.

Median overall survival was more than three years for people who received Herceptin and chemotherapy, Roche said, adding no new safety signals had been observed in the phase III study.

“This treatment combination with Perjeta is the first to have significantly extended survival compared to Herceptin and chemotherapy in people with previously untreated HER2-positive metastatic breast cancer,” Roche’s Chief Medical Officer Hal Barron said in the statement.