Short-course treatment after complete response to pembrolizumab in metastatic urothelial bladder cancer: a case series.

Background: The optimal duration of treatment for metastatic patients who achieve a complete response with immune checkpoint inhibitors is unknown. Methods: The outcome for six metastatic bladder cancer patients who received short course of pembrolizumab is reported. Results: A median number of seven cycles of pembrolizumab was given. After a median follow-up of 38 months, progressive disease was confirmed in three patients. All patients relapsed in lymph nodes and underwent pembrolizumab rechallenge: one achieved a complete response, another a partial response. Conclusion: Our case series paves the way for discontinuation of pembrolizumab in patients who achieve a complete response since three out of six patients remain free of disease after 3-year follow-up. Prospective studies are required to confirm our results.