Management of BCG Failure in Non-Muscle Invasive Bladder Cancer

At the American Society of Clinical Oncology virtual meeting, attendees saw and heard new data on checkpoint inhibition using atezolizumab in Bacille Calmette-Guérin (BCG) refractory nonmuscle-invasive bladder cancer.

In this exclusive MedPage Today video, Shilpa Gupta, MD, a genitourinary oncologist from the Cleveland Clinic in Ohio, discusses the importance of these findings.

Following is a transcript of her remarks:

This was a phase II trial of atezolizumab in BCG-unresponsive, nonmuscle invasive bladder cancer. The SWOG S1605 trial. This was a single arm phase II trial and patients were BCG unresponsive and had high-risk nonmuscle invasive bladder cancer. This data is only for the CIS cohort. And total number of patients enrolled in this study was 172. And the ones enrolled on the CIS cohort was 74. Patients received atezolizumab as the treatment after BCG failure.

And the primary endpoint in this study was complete response at six months, which was mandated as an end point by the FDA based on a biopsy at six months. Notably in other trials in this setting, the primary endpoint was defined as complete response rates at three months. But in this study it was CR [complete response] rates at six months. In this study, they found that the complete response rates of six months were 27%. It did not meet the primary endpoint at the interim futility analysis.

Interestingly, the unplanned secondary endpoint of complete response rates at three months was 42%. And it was comparable to pembrolizumab from the KEYNOTE-057 trial, which led to approval of pembrolizumab in this setting.

In this study, there was one treatment related death. Overall, we have one drug approved in this setting so far, that is pembrolizumab based on the KEYNOTE-057 trial. There’s another trial that showed a lot of promise, which showed that the complete response rates at three months were 53%. Now that was not a primary endpoint of this study, but it did show 42% complete response rates at three months.

Now the key in this setting is that the gold standard has been radical cystectomy, and we really need to see long term durability data of maintaining complete responses to see how effective a therapy would be. And the median duration of response so far for pembrolizumab is 12.7 months. And for this study, we don’t have a long enough follow up yet, but time will tell about the durability of responses.