Long‐Term Clinical Response After Low‐Dose and Short‐Duration Cemiplimab Therapy in a Patient With Xeroderma Pigmentosum in Nepal

Xeroderma pigmentosum (XP), an autosomal recessive condition affecting DNA repair, is associated with a high risk of multiple and aggressive cutaneous squamous cell carcinomas (CSCCs). Because of numerous and/or locally advanced tumors, surgery may be difficult. The immune checkpoint inhibitor cemiplimab has been approved in advanced, unresectable, and/or metastatic CSCCs. However, it is not available everywhere and is typically inaccessible to the poor without health insurance. We hereby report our experience of using low‐dose and short‐duration treatment with cemiplimab in a 15‐year‐old male with XP and multiple advanced CSCCs. The patient showed a complete or partial response to all tumors. The therapy was subsequently stopped after eight pulses due to the COVID‐19 pandemic. The response lasted for 5 years without subsequent treatment, after which one of the tumors recurred and the new ones developed. Checkpoint inhibitors were no longer available at this time.