Immune checkpoint inhibitors (ICIs) are commonly used in the therapeutic arsenal of metastatic melanoma, Merkel cell carcinoma and cutaneous squamous cell carcinoma, thanks to their inhibiting effects on cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) and anti-programmed death-1 (anti-PD1) respectively. These treatments can induce numerous cutaneous and non-cutaneous adverse effects that are mainly due to their immunological action. Their most frequent adverse effects are dysthyroidism, autoimmune hepatitis, colitis and skin disorders. Among those, pruritus is frequently reported as a side effect of these treatments. Its incidence has been estimated between 11% and 47%. Pruritus can deeply affect the patient's quality of life and may lead to treatment discontinuation. Until now, ICI-related pruritus has been poorly studied and it is not understood. In the literature, data on the presence and characteristics of pruritus in patients treated by ICIs were provided, without analyzing the causes of this pruritus. Indeed, it is not known if the occurrence of pruritus is related to direct or indirect effects of ICIs. Some authors reported a correlation between the occurrence of cutaneous adverse events under ICIs and the survival. The principal aim of our study was to analyze the putative causes of pruritus occurring in patients treated with ICIs for melanomas and cutaneous carcinomas. The other objectives were to assess the association between the occurrence of pruritus and survival, and between the other adverse events and pruritus.

Inclusion Criteria:

• age 18 years and older,
• treated with ICIs (nivolumab, pembrolizumab, ipilimumab, cemiplimab) for melanoma, squamous cell carcinoma or Merkel cell carcinoma
• not having formulated any opposition

Exclusion Criteria:

• age under 18 years,
• adults not legally competent,
• presence of pruritus at the inclusion,
• participation refusal

patients treated with ICIs (nivolumab, pembrolizumab, ipilimumab or cemiplimab)

All collected data that underlie results in a publication

Data will be available beginning six month and ending five years following the end study

Data access requests will be reviewed by the internal committee of Brest UH. Requestors will be required to sign and complete a data access agreement.