PENILE CANCER is rare, outcomes remain poor, and there are few data from randomized trials to guide treatment decisions. However, in the small phase II VinCaP study, presented at the 2018 Genitourinary Cancers Symposium, 45.5% of patients with advanced or metastatic penile cancer had a clinical benefit from vinflunine, a third-generation compound with less toxicity than older vinca alkaloids.¹ The results suggest that selected patients may benefit from this agent. 

“A total of 45.5% of patients with advanced or metastatic penile cancer had a clinical benefit from vinflunine.”

— Lisa Pickering, FRCP, PhD

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“The good news is we were successfully able to recruit patients with penile cancer to a multicenter trial. Few previous trials of other agents within the past 10 years have met their primary endpoints. This multicenter, single-arm, phase II trial did meet the primary endpoint, and the objective response rate is comparable to combination regimens tested in other phase II trials in penile cancer,” said lead author Lisa Pickering, FRCP, PhD, a consulting medical oncologist at St. George’s Healthcare and Royal Marsden NHS Foundation Trust, London. “Vinflunine does cause neutropenia and requires monitoring,” she added, but “more than half of the patients completed planned treatment.” 

Since 2010, cisplatin-based combination therapy has been used to treat penile cancer, but many patients are cisplatin-ineligible or experience disease progression or toxicity when treated with cisplatin. Thus, treatment of these patients represents an unmet need. 

Study Details 

VINCAP ENROLLED 25 patients from 8 different sites over nearly 3 years. All patients had locally advanced squamous cell carcinoma of the penis, mainly with cisplatin-ineligible and/or unresectable disease. Patients received vinflunine at 320 mg/m2 every 3 weeks for 4 cycles. The primary endpoint of the study was clinical benefit rate after 4 cycles. If patients did not experience disease progression on chemotherapy, they could continue vinflunine. 

The study was halted for close inspection after two on-treatment deaths occurred, but it was subsequently re-opened for recruitment. 

The median age of patients was 68 years (range, 33–84 years old). The study population was relatively elderly, Dr. Pickering noted. Of the 26 patients, 24 had stage IV disease and 2 patients had stage IIIb disease. 

A total of 22 patients were evaluable. Twelve patients completed four cycles or more, and seven patients received more than four cycles. 

Key Findings 

THE MEDIAN follow-up was 16.3 months. For the primary endpoint, 10 patients had an objective response or stable disease, for a clinical benefit rate of 45.5%. The median progression-free survival was 2.9 months, and median overall survival was 8.4 months. 

Adverse events were collected until the end of cycle four. Prespecified adverse events that occurred in at least 10% of patients included constipation (64%, 1 grade 3) and neutropenia (32%, 5 grade 3 or higher). For nonspecified adverse events, 15 patients (68%) experienced grade 3 or higher adverse events, mainly fatigue, anorexia, and constipation. ■

DISCLOSURE: Dr. Pickering reported no conflicts of interest. 

REFERENCE 

1. Pickering LM, Tovey H, Elliott T, et al: VinCaP: A phase II trial of vinflunine chemotherapy in locally advanced and metastatic carcinoma of the penis (CRUK/12/021). 2018 Genitourinary Cancers Symposium. Abstract 547. Presented February 9, 2018.