About the Study
The trial, called IMvigor210, is a single-arm phase II study of atezolizumab in patients with locally advanced or metastatic bladder cancer. All patients had urothelial cancer, which is the most common type of bladder cancer in the United States.
The study included two groups of patients: those receiving atezolizumab as a second-line therapy and those receiving atezolizumab as an upfront treatment. The researchers have previously reported results from the second-line therapy group. Based on those results, the FDA granted accelerated approval for atezolizumab after treatment with a platinum-based regimen.
Key Findings
With a median follow-up of 14.4 months, 28 out of 119 (24%) patients responded to the treatment. The longest duration of response thus far is greater than 18 months, and 21 of 28 (75%) responses were ongoing at the time of data analysis. The median overall survival was 14.8 months.
Overall, atezolizumab was well-tolerated, with only 10-15% of patients experiencing severe adverse effects. The most common toxicities were 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 Dr. Balar.