Background and Importance In Italy, monoclonal antibodies acting on programmed cell death protein (PD-1), nivolumab (N) and pembrolizumab (P), or on the PD-L1 ligand, atezolizumab or durvalumab, are authorised for the treatment of NSCLC. Registration RCTs may not give definitive answers regarding the optimal ICI's duration of treatment (DOT). There is evidence that treatment may be interrupted before progression, or before scheduled cycles are completed for different reasons and that potentially affects efficacy. Are the causes for patient discontinuation treatment (TDC) in RCTs and in the real world comparable?

Aim and Objectives Aim: evaluate the appropriateness of treatment choices by analysing DOT with ICI in a cohort of patients with NSCLC

Material and Methods For 27 months data were recorded on patients treated in I-line with P or combinations of P+pemetrexed+platinum chemotherapy (PPC), or in II-line with N. The percentage of PD-L1 expression (PD-L1el) was observed; median DOT was measured, and the data were stratified according to treatment discontinuation causes.

Results A total of 73 patients were treated, 62% men, 38% women, 29% smokers, 3% non-smokers, 40% ex-smokers, and 28% n.a. At the present date 5% of the 73 patients are undergoing treatment and 4% completed all cycles of therapy. Patients were treated with: 33% N, 49% P, and 18%PPC. The PD-L1el in the population treated was for: N 4% >50%, 63% <1%, 33% n.a. versus RTC 77% >5% and 33% >50% (3); for P: <5% 8% and >50% 92% versus RTC 100% >50% (4); for PPC: 67% <5% and 33% < 50% versus RCT-data <=50% 63% and 32% > 50%. Median DOT for P (8 vs 7.9 months), N (5 vs 2.8 months), and PPC (2 vs 9.8 months) in RWD and RCTs respectively. RWD TDC: 96% 7%(4% N, 3% P 17% C), progression 67%(79% N, 53% P and 67% PPC) toxicity 22%(13% N, 28% P and 17% PPC). From RCT data: death/progression (67%N, 47% P, 30.8% PC) and toxicity(3%N, 13.6% P, 13.8%PPC)

Conclusion and Relevance RCT and RWD data are conflicting. Median DOT for P and the N death/progression rate are comparable. The treatment choices made were appropriate, maximising treatment efficacy, while respecting the risk/benefit profile in a population different from that of the RCTs

Conflict of Interest No conflict of interest