The following article features coverage from the American Society of Clinical Oncology (ASCO) 2018 meeting.

Earlier pembrolizumab treatment using a “switch maintenance” approach may delay disease progression in patients with metastatic urothelial carcinoma (mUC) who achieve stable disease on first-line platinum-based chemotherapy, investigators reported at the 2019 American Society of Clinical Oncology annual meeting in Chicago.

In a phase 2 double-blind trial, Matthew D. Galsky, MD, of the Icahn School of Medicine at Mount Sinai in New York, and colleagues enrolled 107 patients with mUC who achieved at least stable disease after up to 8 cycles of first-line platinum based chemotherapy. They randomly assigned 55 patients to receive pembrolizumab 200 mg IV every 3 weeks and 52 to receive placebo for 24 weeks. Patients who progressed on placebo could cross over to the pembrolizumab group.

At a median follow-up of 14.7 months, 41 patients had died and 26 patients in the placebo arm crossed over to pembrolizumab. The 18-month restricted mean progression-free survival time was 8.2 months in the pembrolizumab arm compared with 5.6 months in the placebo group, Dr Galsky’s team reported.

Patients in the pembrolizumab and placebo groups had a median age of 68 and 65 years, respectively. Visceral metastases were present in 71% and 62% of patients, respectively.

Grade 3-4 treatment-emergent adverse events occurred in 56% of the pembrolizumab group and 48% of placebo recipients.

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Reference

Galsky MD, Pal SK, Mortazavi A, et al. Randomized double-blind phase II study of maintenance pembrolizumab versus placebo after first-line chemotherapy in patients (pts) with metastatic urothelial cancer (mUC): HCRN GU14-182. Presented at the 2019 American Society of Clinical Oncology annual meeting in Chicago, May 31 to June 4. Abstract 4504.