Surrogates of response to treatment of non-small cell lung cancer with immunotherapy: Toxicity and leukocyte ratios—Experience of a center

e21052 Background: Immunotherapy is proposed as a therapeutic novelty in metastatic non-small cell lung cancer (NSCLC), in many cases already in front line. It presents different adverse effects than traditional schemes, due to the stimulation of the immune system. There is a possible relationship between toxicity and response. Neutrophil-to-lymphocyte ratio (NLR) as a possible predictive factor of response. Objectives: Evaluating the response according to the toxicity degree in NSCLC patients in real clinical practice. Analyze whether pretreatment NLR high patients have a worse prognosis. Methods: Observational, retrospective, analytical, single-center study. HCULB stage IV NSCLC patients with inmunotherapy treatment during 2016-2018. Descriptive and multivariate analysis. Toxicity grade: CTCAE version 4.0. Response assessment: RECIST 2.0 and immunorelated criteria. Toxicity degree and response (global and individualized results according to treatment and histology). Neutrophil-to-lymphocyte ratio and response. Results: N = 43 patients (35 men, 8 women). Average age 64 years. Response: 3 complete response (CR) (toxicity ≥2), 13 partial response (PR) (toxicity ≥1), 13 stable disease (SD), 12 progression (P) (only 4 toxicity and ≤2), 2 not evaluated. Hypothyroidism as the most common irAE. Relationship between toxicity and response: the absence of irAEs conditions worse prognosis p < 0.05. Histology: 25 adenocarcinoma [18 with irAES (1 CR, 7 PR, 8 SD,) and 7 without (1 SD, 5 P, 1 no ev.)]; 17 squamous [13 with irAES (1 CR, 6 PR, 4 SD) and 4 without (3 P, 1 no ev.)]; 1 adenosquamous with irAES and CR. Drug: Atezolizumab N = 8 [6 with irAES (2 PR, 3 SD, 1 P) and 2 without (both P)], Nivolumab N = 16 [9 with irAES (1 CR, 3 PR, 3 SD, 2 P) and 7 without (1 SD, 4 P, 2 no ev.)], Pembrolizumab N = 19 [17 with irAEs (2 CR, 8 PR, 6 SD, 1 P) and 2 without (both P)]. Significant positive correlation between toxicity and response (p < 0.001) R = 0.067, (CI 99% 0.378-0.837), regardless of histology and drug. It is observed a better response in those patients who presented a NRL close to 3 or less at the beginning of treatment. On the contrary, it is observed that subjects with NRL greater than 4 obtained worse results when they were treated with immunotherapy. Conclusions: The appearance of irAES like a response indicator of immune system, seem to conditione better evolution. In contrast, the absence of toxicity predicts a worse prognosis. Further studies with a larger sample are needed to confirm our findings about the predictive value of NLR and optimize therapeutic regimens if necessary.