Efficacy and safety of second-line immunotherapy in patients with advanced non-small cell lung cancer.

e20571 Background: Patients (Pts) with advanced non-small cell lung cancer (NSCLC) face limited treatment options. Immunotherapy (IO) has revolutionized the treatment of NSCLC in this setting. The objective of our study is to evaluate the efficacy and safety of atezolizumab (Az) in Pts with advanced NSCLC in the second-line setting following progression on platinum-based chemotherapy (CT) in the Huelva area. Additionally, we aim to compare the results with those obtained in the phase 2 POPLAR and phase 3 OAK clinical trials. Methods: This is a descriptive and observational study conducted on patients with advanced NSCLC who received second-line IO with atezolizumab 1200 mg/1680 mg every 3 or 4 weeks, from 2015 to 2023 in the Huelva area (Spain). SPSS Statistics 22 was used for data analysis. Results: 26 Pts were treated, median age 67 years and 88.5% men. ECOG PS 0-1 in 92.3%. According to smoking habits, 42.3% were ex-smokers and 38.5% were active smokers. Regarding histology, 53.8% were non-squamous. 73.1% were inicial stage IV and 23% were stage III. Depending on the expression of PDL-1, PDL-1 was < 1% in 34.6% (9 Pts) of the sample, between 1-49% in 53.8% (14 Pt) and unknown in 3 Pts. 26.9% of patients achieved disease stability and 11.5% achieved partial response. The response has not been evaluated in 38.5% because these patients maintain treatment. The adverse effects (AE) suffered by patients treated with Az in the second line were 53.8% grade (G) 1- 2 and 7.7% G 3-4. The most frequent were asthenia (48%), pruritus and arthralgia in 15.4%, both cases, and skin toxicity in 11.5%. In the case of the 2 Pts with G 3-4 toxicity, they were due to autoimmune anemia and asthenia with subsequent to grade 1, so treatment did not have to be interrupted. The median progression-free survival (PFS) was 2.7 months (m) (95% CI 0-6.8) and the median overall survival (OS) was 5.2 m (95% CI 0.5- 9-9). In both cases the results were not statistically significant. According to PDL1, no statistically significant differences were found in the subgroup analysis. Conclusions: Based on our results and those of the Phase 2 POPLAR and Phase 3 OAK studies, we consider that Az has an acceptable safety profile, with fewer G 3-4 side effects compared to CT, so a lower percentage of Pts drop out the treatment. Although the PFS was similar to the phase II-III studies, the OS was lower, probably due to the percentage of Pts with rapid progression and patients currently continuing to receive treatment, being a limitation in our study along with the small sample size. Despite this, our results are encouraging regarding the benefit of IO in Pts. Therefore, we conclude that the use of IO in these Pts falls within good clinical practice, offering them a clearly effective therapy and thus avoiding treatments with greater toxicity such as CT.