Long-term immune-related adverse events under PD-1 inhibitors: a multicenter prospective cohort study (MELBASE).

Abstract

10057 Background: PD-1 inhibitors (anti-PD1) are frequently associated with immune-related adverse events (IRAE). Since melanoma patients included in clinical trials were frequently treated during two years, data on IRAE occurring after 2 years of treatment are lacking. This study aimed to describe IRAE in melanoma patients treated with anti-PD1 for longer than 2 years in a real-life setting. Methods: Patients were screened from MelBase, a French multicentric biobank dedicated to the prospective follow-up of unresectable stage III or IV melanoma. All patients who received anti-PD1 for at least 2 years between January 2013 and November 2019 were included. Among them, patients who experienced IRAE and long-term IRAE defined as IRAE occurring after 2 years of anti-PD1 were identified. Results: Among 1849 patients with advanced melanoma included in Melbase, 119 patients received anti-PD1 monotherapy during at least 2 years, from January 2013 to November 2019, with a median follow-up of 41.7 months (25.2-57.5). Patients characteristics at treatment initiation were: male gender (61%), mean age of 63 years old, past history of autoimmune disease (11%), BRAF WT (72%), AJCC stage IV (84%), brain metastases (22%), ECOG 0-1 (88%) and normal LDH (56%). Patients were treated with Nivolumab (n = 53) or Pembrolizumab (n = 66). IRAE occurred in 99 patients (83%) with a median time of 13.3 months (0-53.9), including severe IRAE (grade 3 or 4) in 30 patients (30%). Long-term IRAE, mostly grades 1-2, occurred in 52 patients (43%). Long-term IRAE led to 5 hospitalizations (4%) of which 4 were grades 3-4. Among patients with long-term IRAE, 45 patients (87%) previously experienced IRAE within the first 2 years of anti-PD1 and 29 patients (56%) experienced multiple IRAE. Conclusions: Our data demonstrate that long-term IRAE are frequent especially in patients who already experienced IRAE within the first two years of treatment. These data should be taken into account to establish formal recommendations on the duration of anti-PD1 therapy.