Starting immunotherapy for bladder cancer shortly after initial treatment with chemotherapy is better than taking an extended break from cancer treatment, according to results from a study reported at the American Society of Clinical Oncology annual meeting.

The researchers studied 700 patients with locally advanced or metastatic bladder cancer whose disease had not progressed while receiving chemotherapy. They randomly assigned patients to receive supportive care alone or maintenance treatment with avelumab plus supportive care.

Median survival was 21 months in the avelumab arm compared to 14 months in the supportive care–only arm. The treatment benefit occurred regardless of whether patients’ tumors expressed PD-L1, which is the target for avelumab.

Patients in the supportive care arm had the option of receiving avelumab after their cancer had progressed, but only about half of patients did so, the researchers reported, although the study findings did not explain why.

“After first-line chemotherapy, only a minority of patients get second-line treatment. And outcomes with second-line treatment are poor, because the disease is aggressive and grows rapidly,” the researchers said.

The clinical trial findings led to avelumab’s July 1, 2020, U.S. Food and Drug Administration approval as first-line treatment for advanced bladder cancer that responded to platinum-based chemotherapy.