Pembrolizumab plus chemo efficacious in advanced PSCC

Treatment with the combination of pembrolizumab plus chemotherapy elicits response in patients with advanced penile squamous cell carcinoma (PSCC) while having a manageable safety profile, according to the phase II HERCULES trial.

HERCULES included 33 patients (median age 56 years) with metastatic, recurrent, or locally advanced disease not amenable to curative-intent therapy.

The patients were treated with fluorouracil, administered intravenously at 1,000 mg/m² per day on days 1–4; cisplatin, administered intravenously at 70 mg/m² (or carboplatin, area under the curve of 5) on day 1; and pembrolizumab, administered intravenously at 200 mg on day 1 every 3 weeks for 6 cycles, followed by 200 mg, intravenously every 3 weeks for up to 34 cycles. Those without disease progression received maintenance intravenous pembrolizumab at 200 mg, every 3 weeks for up to 34 cycles.

The primary endpoint was the overall response rate (ORR). Progression-free survival (PFS), overall survival (OS), and safety were also evaluated.

Of the patients, 24 (64.9 percent) had metastatic disease, eight (21.6 percent) had recurrent disease, and five (13.5 percent) had locally advanced disease. The ORR was 39.4 percent (95 percent confidence interval [CI], 22.9–57.9).

Over a median follow-up of 24.0 months, the median PFS was 5.4 months (95 percent CI, 2.7–7.2) months and the median OS was 9.6 months (95 percent CI, 6.4–13.2).

Treatment-related adverse events (TEAEs) occurred in 91.9 percent of patients overall, including 51.4 percent with grades 3–4 TEAEs. Immune-related TEAEs were documented in 21.6 percent of patients, including 5.4 percent with grade 3–4 events. There were no treatment-related deaths.