ASCO 2016: Previously untreatable advanced bladder cancer patients respond to immunotherapy

by Bruce Sylvester: Anti-PD-L1 immunotherapy atezolizumab (TECENTRIQ) has shown efficacy in previously untreated patients with advanced bladder cancer who are ineligible for standard treatment with cisplatin.

Researchers reported this finding in June, 2016 at the 2016 Annual Meeting of ASCO/American Society of Clinical Oncology. They reported that atezolizumab shrank tumors in about a quarter of the trial subjects and led to a median survival of 14.8 months.

“Up to half of patients with advanced bladder cancer are too frail to receive the only known survival-prolonging treatment, cisplatin. There is really no standard treatment for such patients,” said lead investigator Arjun Vasant Balar, MD,  assistant professor of medicine at the New York University Langone Medical Center and Director of Genitourinary Medical Oncology at the NYU Perlmutter Cancer Center in New York, NY. “We are encouraged to see that atezolizumab immunotherapy may help address this major unmet need.”

The trial, called IMvigor210, was a single-arm phase II study of atezolizumab in patients with locally advanced or metastatic bladder cancer. All patients had urothelial cancer, the most common type of bladder cancer in the United States.

The study included two groups of subjects, those getting atezolizumab as a second-line treatment and those getting atezolizumab as their first treatment.

The researchers had previously reported second-line therapy group results, and based on those results the FDA granted accelerated approval for atezolizumab after treatment with a platinum-based regimen.

With regard to the previously untreated group, the investigators reported that, with a median follow-up of 14.4 months, 28 out of 119 (24%) subjects responded to the treatment. Longest duration of response was greater than 18 months, and 21 of 28 (75%) responses were ongoing at the time of data analysis. Median overall survival was 14.8 months.

Atezolizumab was generally well-tolerated, with 10-15% of patients reporting severe adverse effects, most commonly hypothyroidism, liver function abnormalities, rash, and diarrhea.

“The majority of our patients had few or no side effects from atezolizumab and only 6% of patients discontinued treatment because of toxicity. This is in stark contrast to the approximate 20% rate of treatment discontinuation from toxicity observed with carboplatin-based chemotherapy regimens. Immunotherapy appears to be much easier to tolerate than chemotherapy, and this is especially important for elderly patients,” said Balar.

IMvigor210 is the first trial to test the efficacy of atezolizumab as a first treatment of patients with advanced bladder cancer.