Induced Remission of Metastatic Squamous Cell Carcinoma with an Immune Checkpoint Inhibitor in a Patient with Recessive Dystrophic Epidermolysis Bullosa.

Recessive dystrophic epidermolysis bullosa (RDEB) is a genodermatosis that leads to skin fragility and chronic wound formation. Patients with RDEB are at risk for cutaneous squamous cell carcinoma (SCC) which is a major cause of morbidity and mortality in these patients. No standard of care exists for the treatment of SCC in this patient population and therapy is based on anecdotal reports and expert opinion. We report a 32-year-old man with RDEB with previously localized SCC who later developed metastatic SCC. He was started on cemiplimab (an immune checkpoint inhibitor) 350 mg IV every 3 weeks. An objective radiological response was noted within 3 cycles. On 14 months follow-up, there was a durable response to treatment clinically and on imaging, without immune-related adverse events. To our knowledge, this is the first case report describing safe administration of immune checkpoint inhibitors in a patient with RDEB with objective and durable response of metastatic SCC. Larger case series and controlled clinical trials are needed to further investigate these medications in the RDEB population, given their high burden of aggressive and often lethal SCC.