Eosinophilia during treatment of immune checkpoint inhibitors (ICIs) predicts succeeding onset of immune-related adverse events (irAEs)

Abstract Background Patients with sensitive gene mutations could achieve better overall survival by taking targeted drugs. Many trials have shown that non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EFGR) mutation responded to PD-1/PD-L1 inhibitors worse than EGFR wild-type. And subgroups of trials have also reported the efficacy of PD-1/PD-L1 inhibitors in the treatment of NSCLC patients with other sensitive gene mutations. So, we conducted a complementary systematic review and meta-analysis to compare efficacy of PD-1/PD-L1 inhibitors for NSCLC patients with sensitive gene mutations. Methods PubMed, EMBASE, Web of Science and the Cochrane Central Register of Controlled Trials (Central) databases were searched for all clinical trials in NSCLC until 5th of January 2019. Eligible studies included randomized controlled trials (RCTs) comparing PD-1/PD-L1 inhibitors with chemotherapy in NSCLC patients with sensitive gene mutations. The hazard ratio (HR) and 95% confidence intervals (CIs) of overall survival (OS) or progression-free survival (PFS) were used. Results We analyzed 193 patients in this study. Among cumulative total of 210 patients, 197 were treated with PD-1 or PD-L1 inhibitors. Another 8 and 5 patients were treated with CTLA-4 inhibitor alone and combination with PD-1 inhibitor, respectively. This study included non-small cell lung cancer (n = 106; 50.5%), kidney (n = 23; 10.9%), melanoma (n = 30; 14.3%), gastric (n = 19; 9.0%), Hodgkin lymphoma (n = 11; 5.2%), urothelial carcinoma (n = 10; 4.8%) and others (n = 10; 4.8%). Any grade of irAEs occurred in 73 (34.8%) cumulative patients, and among them, 28 (13.3%) were classified as grade 3-5. The most common irAEs in any grade were skin disorders (n = 29) and endocrine disorders including thyroid dysfunction and adrenal insufficiency (n = 28). Eosinophilia occurred in 57 cumulative patients (27.1%), and 21 patients out of them had eosinophilia from baseline. Among the clinical and laboratory factors, only eosinophilia was significantly associated with the occurrence of any grade of irAEs in both univariate (p = 0.010) and multivariate (p = 0.0463) analyses. Notably, endocrine irAEs were significantly related to eosinophilia (p = 0.0287). Conclusions Eosinophilia after the initiation of treatment with ICIs predicts succeeding onset of irAEs. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure Y. Miura: Honoraria (self): Ono; Honoraria (self): Bristol-Myers Squibb Japan; Honoraria (self): Chugai. T. Takano: Honoraria (self): Daiichi Sankyo; Honoraria (self): Kyowa Hakko Kirin; Honoraria (self): Eisai; Research grant / Funding (self): MSD; Research grant / Funding (self): Ono; Research grant / Funding (self): Merck Serono; Research grant / Funding (self): Taiho; Research grant / Funding (self): Novartis; Research grant / Funding (self): Chugai. All other authors have declared no conflicts of interest.