OTHR-37. Pediatrics Cutaneous Reactions in Patient Treated with the Mitogen-Activated Protein Kinase Extracellular Signal-Regulated Kinase Inhibitor Trametinib

OBJECTIVE: To describe the cutaneous adverse effects (AE) to MAPK Extracellular Signal-Regulated Kinase (MEK) Inhibitor Trametinib in the pediatric population. METHODS: This was a retrospective single-center study. Included were all pediatric patients, treated with trametinib, for an oncologic indication. All patients were evaluated by a pediatric dermatologist, prior to, and during treatment, with documentation of cutaneous findings. RESULT: Twenty patients were enrolled in the study. All patients received treatment with trametinib, of which 6 received a combination of trametinib and dabrafenib (BRAF inhibitor). Out of twenty patients, 18 patients (90%) presented with at least one cutaneous AE. Xerosis and pruritic eczematous changes were the most common (15 patients, 75%), which, in most cases, were tolerable and responded well to the use of emollients and topical corticosteroids. Eleven patients (55%) presented with paronychia which was treated with topical combined corticosteroids antifungals and antibiotics, all with good response. Six patients (30%) presented with acneiform eruption, treated with topical antibiotic, benzoyl peroxide and tretinoin, mostly with good response. Six patients (30%) presented with irreversible hair heterochromia. Reaction grades were reported for cutaneous reactions, most of them were Grade I or II. Only 2 patients reported to have grade III and IV cutaneous reactions: exfoliative dermatitis and erythema multiforme, respectively. Out of 6 patients that received combined treatment of trametinib and dabrafenib one patient had no cutaneous adverse reaction, and one had panniculitis (which was related to dabrafenib). The rest presented relatively mild AE. DISCUSSION: Cutaneous AEs are very common in children and adolescents treated with trametinib, and in most cases are classified as mild. Nevertheless, as this treatment is usually chronic, it is important to inform the patients and their guardians of the potential cutaneous toxicities prior to treatment initiation, and to refer them to a dermatologist for proper management.