ASCO 2018: First-Line Pembrolizumab in Cisplatin Ineligible Advanced Urothelial Cancer-KEYNOTE-052

Chicago, IL (UroToday.com) Over the last several years, pembrolizumab has provided encouraging results across several malignancies, including advanced/metastatic urothelial carcinoma. Last year, initial outcomes of the phase II KEYNOTE-052 study reported that among 370 patients receiving at least one dose of pembrolizumab, 89 (24%, 95%CI 20-29) patients had a centrally assessed objective response, and 74 (83%) of 89 patients had ongoing responses over a median follow-up of 5 months (IQR 3.0-8.6) [1]. Additionally, a PD-L1-expression cutoff of 10% was associated with a higher frequency of response to pembrolizumab: 42 (38%, 95%CI 29-48) of 110 patients had an objective response. Based on these results, pembrolizumab was granted FDA approval for the treatment of cisplatin-ineligible patients with advanced urothelial carcinoma. Dr. Vuky and colleagues at ASCO 2018 annual meeting presented long-term follow-up analysis of KEYNOTE-052. 



Patients enrolled in KEYNOTE-052 were eligible if they: 
  • Were cisplatin ineligible (ECOG performance status 2, or CrCl ≥30 to <60 mL/min, or grade ≥2 neuropathy/hearing loss, or NYHA Class 3 heart failure) 
  • Had advanced urothelial carcinoma 
  • Had received no prior chemotherapy for metastatic disease 
Patients received pembrolizumab 200 mg IV every 3 weeks for up to 24 months. Imaging was performed at week 9, then every 6 weeks for 12 months, and every 12 weeks thereafter. The primary end point was confirmed ORR based on RECIST v1.1 (independent central review). 

For the updated KEYNOTE-052 analysis, efficacy and safety were assessed in 370 patients over a median follow-up of 11.5 months (range 0.1-31.3 months). The median age was 74 years, including 10.8% of patients ≥85 years of age. There were 42.2% of patients that were ECOG performance status 2, and 85.1% had visceral disease. Confirmed ORR was 28.9% (95%CI 24.3-33.8), including 30 (8.1%) patients with complete response and 77 (20.8%) patients with partial response. The median duration of response was not reached (95%CI, 21.4 months-NR), including 82% who had a response of ≥6 months and 68% who had a response of ≥12 months. The median OS was 11.5 months (95%CI 10.0-13.3) and the 6-and 12-month OS rates were 67% and 48%, respectively.  


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The median PFS was 2.3 months (95%CI 2.1-3.4) and the 6-and 12-month PFS rates were 34% and 22%, respectively.  



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Among patients with a PD-L1 expression combined positive score of ≥10 (n=110), ORR was 47.3% (95%CI 37.7-57.0) and median OS was 18.5 month (95%CI 12.2 months-NR).  

Further subgroup median OS results included:  

  • Lymph node-only disease (n=51): not reached (95%CI 12.4 months-NR)  
  • ECOG performance status 0/1 (n=214): 13.1 months (95%CI 11.0-16.8)  
  • ECOG performance status 2 (n=156): 9.7 months (95%CI 5.7-11.6)  
Treatment-related adverse events (AEs) occurred in 67.6% of patients, most commonly (≥15%) fatigue (18.1%) and pruritus (17.8%). Grade ≥3 treatment-related AEs occurred in 20.3% of patients. Immune-mediated AEs occurred in 24.6% of patients. 

Similar to atezolizumab for advanced urothelial cancer, pembrolizumab appears to have clinically meaningful and durable results (follow-up time more than twice as long as reported in the initial analysis) in a heavily treated and comorbid population. For advanced urothelial carcinoma patients that are cisplatin-ineligible, these results are quite encouraging. Data further support the use of pembrolizumab for patients with urothelial carcinoma who are cisplatin ineligible and those for whom chemotherapy may not be suitable. 

Clinical trial information: NCT02335424 

Presented By: Jacqueline Vuky, Oregon Health & Science University, Portland, OR 
Co-Authors: Arjun V. Balar, Daniel E. Castellano, Peter H. O'Donnell, Petros Grivas, Joaquim Bellmunt, Thomas Powles, Dean F. Bajorin, Noah M. Hahn, Ronald De Wit, Mary Savage, Lei Pang, Tara L. Frenkl, Stephen Michael Keefe, Elizabeth R. Plimack; Oregon Health & Science University, Portland, OR; Perlmutter Cancer Center, NYU Langone Medical Center, New York, NY; Hospital Universitario 12 de Octubre, Madrid, Spain; The University of Chicago Medical Center, Chicago, IL; Cleveland Clinic, Cleveland, OH; Dana-Farber Cancer Institute, Boston, MA; Barts Cancer Institute, Queen Mary University of London, London, United Kingdom; Memorial Sloan Kettering Cancer Center, New York, NY; The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University, Baltimore, MD; Erasmus MC Cancer Institute, Rotterdam, Netherlands; Merck & Co., Inc., Kenilworth, NJ; Fox Chase Cancer Center, Philadelphia, PA 

Written by: Zachary Klaassen, MD, Urologic Oncology Fellow, University of Toronto, Princess Margaret Cancer Centre, Twitter: @zklaassen_md  at the 2018 ASCO Annual Meeting - June 1-5, 2018 – Chicago, IL USA

References: 
1. Balar AV, Castellano D, O’Donnell PH, et al. First-line pembrolizumab in cisplatin-ineligible patients with locally advanced and unresectable or metastatic urothelial cancer (KEYNOTE-052): A multicentre, single-arm, phase 2 study. Lancet Oncol 2017;18(11):1483-1492.
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