# Extracorporeal photopheresis for pembrolizumab-induced dermatitis: a case report

## TL;DR

Extracorporeal photopheresis (ECP) successfully treated a patient's severe skin reaction caused by cancer immunotherapy, without worsening their cancer outcome.

## Contribution

This is the first reported case of ECP used to treat immune-related dermatitis from anti-PD-1 therapy.

## Key findings

- ECP significantly improved dermatitis symptoms and reduced skin lesions in a melanoma patient.
- The patient remained cancer-free for 14 months after ECP treatment.
- Immune markers stabilized during ECP treatment.

## Abstract

Immune-related adverse events (irAE) are common in checkpoint blockade–treated patients and limit its clinical application. Corticosteroids are the first-line therapy for treatment of irAE, but animal models clearly demonstrate that steroids diminish anti-programmed cell death protein 1 (PD-1)-induced tumour immunity. Better strategies to manage irAE while preserving anti-tumour immunity are needed. Extracorporeal photopheresis (ECP) was recently introduced as second-line treatment for steroid-refractory immune checkpoint inhibitor (ICI)-related colitis and hepatitis. Here, we extend the application of ECP to immune-related maculopapular rash after adjuvant anti-PD-1 therapy in a single melanoma patient. The patient’s dermatitis markedly improved after off-label ECP, with a substantial reduction in skin lesions and pruritus scores, and stabilization of immune markers. The patient remained well after ECP with no recurrent or metastatic disease at 14 months after starting ECP treatment. Hence, in this case, ECP led to successful resolution of pembrolizumab-induced dermatitis and a favourable oncological outcome.

Treatment of immune checkpoint inhibitor–related adverse reactions with extracorporeal phoropheresis (ECP) has become a hot topic. Here, we extend the application of ECP from colitis, hepatitis and pneumonitis to a case of treatment-refractory immune-related maculopapular rash after adjuvant anti-PD-1 therapy. Under ECP, there was a rapid subjective and objective in the patient’s dermatitis, as well as stabilization of immune markers. Importantly, the patient remained well after ECP with no recurrent or metastatic disease at 14 months.