Panitumumab Treatment for Advanced Penile Squamous Cell Carcinoma When Surgery and Chemotherapy Have Failed

Patients with metastatic penile squamous cell carcinoma (SCC) have a poor prognosis and treatment options are needed when chemotherapy treatment fails. We present the final results of panitumumab treatment from our original series.

Eligibility included patients with unresectable or metastatic penile SCC, Eastern Cooperative Oncology Group performance status of 0 to 2, and failure of at least 1 chemotherapy regimen. Patients received panitumumab 6.0 mg/kg every 2 weeks until disease progression or unacceptable toxicity. Response was assessed by clinical examination or Response Evaluation Criteria in Solid Tumors version 1.1 criteria every 6 weeks, when applicable. Descriptive statistics were calculated and univariable Cox proportional hazards regression analysis was conducted.

Between October 2010 and July 2013, 11 patients were treated. After a median of 5 panitumumab administrations (range, 1-11), we recorded 1 case of Grade 3 cutaneous toxicity and diarrhea each, and 2 cases of Grade 3 mucositis. One patient discontinued treatment because of skin toxicity. Two patients had a complete remission of skin nodules and of skin and nodal metastases, respectively. One patient had a partial regression of skin metastases, and 2 patients stable disease (clinical benefit: 45.5%). Median progression-free survival was 1.9 months (interquartile range [IQR], 0.9-3.0 months) and median overall survival (OS) was 9.5 months (IQR, 4.9-12.6). The presence of visceral metastases showed a trend for association with worse OS (P = .098).

Panitumumab was active and safe in patients with highly pretreated penile SCC. The design of combination or sequential strategies with chemotherapy and in an earlier disease stage is warranted.