Nivolumab Decreases Tumors in Metastatic Bladder Cancer

Nivolumab blocks the activation of the protein PD-1 to prompt an attack by the immune system.

Results from a clinical trial saw reduced tumor burden in 24.4% of metastatic bladder cancer patients with the immune checkpoint blockade drug nivolumab.

Nivolumab blocks the activation of the protein PD-1 to start an immune system attack on T cells, viruses, or bacteria that have specific targets. PD-1 is turned on by PD-L1, often found on cancer cells and other types of cells, and acts as a checkpoint to shut down activated T cells.

The phase 1/2 clinical trial enrolled 78 patients administered nivolumab. The results of the trial showed that 5 (6.4%) had complete responses, 14 (18%) had partial responses where the tumor shrank by at least 30%, and 22 (28.2%) had stable disease.

There were 30 (38%) of patients who had disease progression.

Treatment related adverse events included anemia, elevated lipase, itching, joint pain, low-grade fatigue, nausea, and rash. There were 20.5% of patients with grade 3 or 4 side effects and 2 patients discontinued therapy.

The median follow-up was 213 days and 33.3% of patients stayed on treatment, while 45.6% survived for at least 1 year.

“The response rate is better than we've seen for other potential second-line treatments and nivolumab is really well-tolerated, which is important because bladder cancer patients are a fragile group after frontline treatment with platinum chemotherapy,” said researcher Padmanee Sharma, MD, PhD.

There was no significant difference in response rates in patients with little to no PD-L1 on their tumors and those with higher PD-L1 expression.

“We can get good results without choosing to treat patients based on PD-L1 status,” Sharma said.

The overall survival will be analyzed in conjunction with the phase 2 trial. The initial results of the phase 2 trial will be presented later this year. The findings were presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.