25686 Variability in the dosing of PD1 inhibitors used for treatment of nonmelanoma skin cancers

Abstract

Nonmelanoma skin cancer (NMSC) represents the most common cancer diagnosed in the United States. These tumors are frequently treated by surgical modalities. Patients with advanced disease require a different approach to therapy. Programmed cell death protein 1 (PD1) inhibitors are an emerging immunotherapeutic option for the treatment of a variety of tumors including advanced NMSC. Cemiplimab is a PD-1 inhibitor approved for treatment of locally advanced or metastatic cutaneous squamous cell carcinoma (cSCC) not amenable to curative surgery or radiation. Pembrolizumab and nivolumab are PD1 inhibitors used as off-label therapies for advanced cSCC or basal cell carcinoma (BCC). We conducted a PubMed literature search up to August 8, 2020 to include studies on the use of PD-1 inhibitors in patients with advanced NMSC. Thirty-seven articles reported a total of 432 unique cases of advanced cSCC or BCC treated with PD1 inhibitors. The most common dosing schedules for pembrolizumab (2 mg/kg q3 weeks), nivolumab (3 mg/kg q2 weeks), or cemiplimab (3 mg/kg q2 weeks) were identified. A total of 10 different dosing schedules were identified. Outcomes of these patients ranged between progressive disease to achievement of a complete clinical response. All 3 PD1 inhibitors showed adequate safety profiles with few reported adverse events that were grade 3 or above. The use of cemiplimab, pembrolizumab, and nivolumab for advanced NMSC has shown promising results. However, the literature shows a wide range of dosing regimens for these therapies. Further studies are needed to guide clinicians toward the optimal dosage and the ideal anti-PD1 agent for their patients.