Safety and efficacy of immune checkpoint inhibitors in advanced penile cancer: report from the Global Society of Rare Genitourinary Tumors

Background: Treatment options for penile squamous cell carcinoma (PeCa) are limited. We sought to investigate clinical outcomes and safety profiles of patients with PeCa receiving immune checkpoint inhibitors (ICIs). Methods: This retrospective study included patients with locally advanced or metastatic PeCa receiving ICIs during 2015-2022 across 24 centers in the United States, Europe, and Asia. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method. Objective response rates (ORRs) were determined per RECIST 1.1 criteria. Treatment-related adverse events (trAEs) were graded per the Common Terminology Criteria for Adverse Events v5.0. Two-sided statistical tests were used for comparisons. Results: Among 92 patients, 8 were Asian (8.7%), 6 (6.5%) were Black, and 24 (29%) were Hispanic/Latinx. Median age was 62 (inter-quartile range: 53 to 70) years. 83 (90%) had metastatic PeCa, and 74 (80%) received ≥2nd line treatment. Most patients received pembrolizumab monotherapy (n = 26, 28%), combination nivolumab/ipilimumab +/- multi-targeted tyrosine kinase inhibitors (n = 23, 25%), nivolumab (n = 16, 17%) or cemiplimab (n = 15, 16%) monotherapies. Median OS and PFS were 9.8 (95% CI: 7.7-12.8) months and 3.2 (95% CI: 2.5-4.2) months, respectively. ORR was 13% (n = 11/85) in the overall cohort and 35% (n = 7/20) in patients with lymph node-only metastases. Visceral metastases, ECOG performance status ≥1, and higher Neutrophil/Lymphocyte ratio (NLR) were associated with worse OS. TrAEs occurred in 29% (n = 27) and 9.8% (n = 9) were grade ≥3. Conclusions: ICIs are active in a subset of patients with PeCa. Future translational studies are warranted to identify patients more likely to derive clinical benefit from ICIs.