Immunotherapy: Auto-immune toxicity as a predictive factor of response.

Abstract

e14086 Background: PD-1 and PD-L1 inhibitors have now demonstrated their efficacy. Finding predictive or pre-emptive response factors is crucial and the role of immune-related adverse events (irAEs) is widely debated. The aim of our study was to evaluate the correlation between the occurrence of irAEs and overall survival, according to the time of onset. Methods: We retrospectively collected efficacy and safety data from patients treated with nivolumab, pembrolizumab and atezolizumab for metastatic cancer between July 2015 and January 2019 at the Pitié-Salpêtrière Hospital. Progression-free survival (PFS) and overall survival (OS) were analyzed for the global population, for patients who had an irAES, according to the time of onset (before or after 12 weeks). Results: 158 patients were treated with anti-PD1/PD-L1: 125 patients for NSCLC, 12 for melanoma, 11 for clear cell renal cancer, 5 for bladder cancer, 3 for digestive adenocarcinoma and 2 for mesothelioma. At the cut-off analysis, with a median follow-up of 8.6 months, 63 (40%) patients died, 30(19%) had a progressive disease, 31 (20%) were still receiving an immunotherapy. 25(18%) patients developed irAEs, 18(72%) before 12 weeks of treatment and 7(28%) after. 6 patients had to stop the treatment because of irAEs and 3 of them were still on immunotherapy at the cut-off analysis. Progression disease occurred in 7 patients and 9 died under treatment. Only a trend of efficacy was found between patients with irAEs and those without, with a median PFS of 13.2 vs 9.8 months (HR 1.3; p = 0,4) and a median OS of 28 vs 20 months (HR 1.4; p = 0,4). This statistically non-significant trend was found for OS between patients with an early irAEs and those without any toxicity with a median OS of 28 vs 20 months (HR 1.4; p = 0,8). No statistically difference was found between patients with early irAEs and late irAEs. Conclusions: In our study, 18% of the patients had irAEs. Patients with irAEs seemed to have better OS and PFS but no statistically difference was found. This trend is probably related to patients with late toxicity, which reflects the time of treatment and the increasing probability to develop an irAEs. In our study, early irAEs could not be considered as a reliable preemptive factor of response to immunotherapy.