Roche' bladder cancer drug Tecentriq shrank tumours in 24 percent of patients previously untreated for the disease, raising hopes that it might be approved in the first-line setting.

The Phase II IMvigor210 study also showed that, of those responding to treatment with the drug, 75 percent continued to respond and the median duration of response had not been reached at the time of analysis.

Seven percent of patients taking part in the study achieved a complete response, while the median overall survival was 14.8 months, according to the data, presented at the American Society of Clinical Oncology Conference.

On the safety side, fifteen percent of people receiving Tecentriq (atezolizumab) experienced severe treatment-related adverse events, while six percent experienced an adverse event leading to treatment discontinuation and 35 percent an adverse event leading to dose interruption.

Tecentriq is the first and only cancer immunotherapy cleared in the US to treat locally advanced or metastatic urothelial carcinoma (mUC), but its use is only currently approved after patients have received prior treatment with chemotherapy.

According to Sandra Horning, Roche's chief medical officer, the results "are highly encouraging because about half of all people with this type of bladder cancer are not able to tolerate a cisplatin-based chemotherapy, and alternative treatments bring very limited duration of response".

"We are particularly pleased that the majority of people who responded to Tecentriq continued to respond at the time of analysis," she added.

Around 76,000 Americans are diagnosed with bladder cancer every year. mUC accounts for 90 percent of all cases and can also be found in the renal pelvis, ureter and urethral. Approval of Tecentriq gave patients the first new licensed treatment option in more than 30 years.