Swiss drugmaker Roche Holding released on Friday what it called encouraging results from a study of its closely watched cancer immunotherapy atezolizumab.

Swiss drugmaker Roche's logo is seen at their headquarters in Basel, Switzerland October 22, 2015.

Roche, the world's biggest maker of cancer drugs, said a mid-stage trial of atezolizumab in people with locally advanced or metastatic urothelial carcinoma (mUC), showed median overall survival of 11.4 months in people with higher levels of PD-L1 expression and 7.9 months in the overall study population.

It showed that 84 percent of people who responded to atezolizumab continued to respond regardless of their PD-L1 status when the results were assessed with longer median follow-up of 11.7 months.

The therapy was well tolerated and adverse events were consistent with those observed in previous updates, it said.

"It is encouraging to see that the majority of people with advanced bladder cancer who responded to atezolizumab maintained their response with longer follow up," said Sandra Horning, Roche's chief medical officer and head of global product development.

Roche plans to submit the data soon to health authorities and the U.S. Food and Drug Administration under breakthrough therapy designation designed to speed the development and review of medicines that may demonstrate substantial improvement over existing therapies for serious diseases.

Source: Reuters