Posted: Friday, July 14, 2023
The durability of complete responses to pembrolizumab was investigated in patients with advanced urothelial cancer. “This post hoc exploratory analysis suggests complete responses with pembrolizumab were more durable than complete responses with chemotherapy in patients with advanced urinary carcinoma, with corresponding longer progression-free survival and overall survival,” said Ozgur Ozyilkan, MD, of Adana Baskent University, Adana, Turkey, and colleagues, at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4513).
The retrospective study examined patients with advanced urinary carcinomas from the phase III KEYNOTE-361 study. The study assigned patients on a 1:1 basis to receive pembrolizumab plus chemotherapy or chemotherapy alone. The investigators reported that 34 patients achieved a complete response with pembrolizumab, and 43 patients achieved a complete response with chemotherapy. Patients who had achieved a complete response were then assessed for durability in the present study.
The authors reported that the median duration of response was not reached for patients treated with pembrolizumab but was 12.8 months for those treated with chemotherapy. Long-term complete responses of more than 24 months were observed in 75.5% of the pembrolizumab group versus 37.1% of the chemotherapy group. Median progression-free survival was significantly improved in the pembrolizumab arm, with a 24-month progression-free survival rate of 75.5% versus 42.2% in the chemotherapy arm. Although median overall survival was not reached in both arms, the 24-month overall survival rates were higher for patients treated with pembrolizumab (94.1% vs. 69.5%).
Furthermore, 51.2% of patients treated with chemotherapy experienced disease progression after a complete response and required subsequent therapy. This rate was higher than that of the pembrolizumab group, in which 5.9% of patients required additional therapy.
Disclosure: Dr. Ozyilkan reported no conflicts of interest. For full disclosures of the other study authors, visit coi.asco.org.