Posted: Monday, July 31, 2023
Consistent with the previous findings of the KEYNOTE-361 and KEYNOTE-045 trials, monotherapy with the PD-1 inhibitor pembrolizumab remains an efficacious and safe treatment option for patients with advanced urothelial carcinoma, irrespective of histologic subtype, according to a presentation given at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4512). However, additional investigative efforts with larger sample sizes and a more comprehensive histologic classification system are warranted, explained Patrizia Giannatempo, MD, of the Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, and colleagues.
A total of 307 patients from the KEYNOTE-361 trial and 268 patients from the KEYNOTE-045 trial with advanced urothelial carcinoma were recruited for this exploratory analysis. Patients from the KEYNOTE-361 trial had no history of systemic therapy. Patients recruited from the KEYNOTE-045 trial had evidence of disease progression or relapse after being treated with one line of platinum-based chemotherapy. All patients were limited to having pure transitional cell or mixed predominant transitional cell histology. Patients received 200 mg of intravenous pembrolizumab every 3 weeks for up to 2 years or until they exhibited evidence of disease progression or treatment-related toxicities.
The study authors reported a similar overall duration of response for all histologic subtypes (KEYNOTE-361: pure transitional cell = 28.2 month; mixed transitional cell = not reached; KEYNOTE-045: pure transitional cell = 19.7 months; mixed transitional cell = not reached). This trend was similarly observed for the overall response rate (29.3% vs. 40.7% and 21.0% vs. 24.4%), overall survival (14.8 months vs. 16.2 months and 9.7 months vs. 11.6 months), and median progression-free survival (3.9 months vs. 2.2 months and 2.1 months vs. 2.1 months), respectively. Furthermore, rates of treatment-related adverse events were also similar irrespective of histologic subtype (17.3% vs. 18.5% and 16.9% vs. 17.3%), respectively.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.