IntroductionChemotherapy combined with immunotherapy (CT-IO) is the standard treatment for patients with Extensive-Stage Small Cell Lung Cancer (ES-SCLC). This study evaluates the effectiveness of second-line (2L) following CT-IO. Patients and MethodsAll patients from 10 centers who received a 2L after a first-line CT-IO were included. They were divided into 3 groups: platinum-based, lurbinectedin or others (topotecan, CAV, taxanes). We assessed overall survival (OS) and 2L progression-free survival (2L-PFS) according to treatment and platinum free-interval (PFI) < or ≥ 90 days. ResultsAmong 82 patients included, median age was 67.0 years, 29.3 % had a Performans Status ≥ 2, 36.6 % had brain progression, 69.5 % were considered “platine-sensitive” and 30.5 % “platine-resistant” (PFI ≥ or < 90 days, respectively). As 2L, 37/82 patients (45.1 %) received platinum-doublet, 21/82 (25.6 %) lurbinectedin and 24/82 (29.3 %) others. Patients with a PFI ≥ 90 days received mainly platinum-based rechallenge (34/57, 59.6 %). With a median follow-up of 18.5 months, the median OS was 5.0 months (95 %CI, 1.5–7.9) / 6.8 months (95 %CI, 5.5–8.7) for platinum-resistant / sensitive, respectively (log rank p = 0.017). The median 2L-PFS was 1.9 months (95 %CI, 1.2–4.7) / 3.9 months (95 %CI, 2.9–6.0) for platinum-resistant / sensitive, respectively. Median OS was 8.1 (95 %CI, 6.3–12.9) / 4.9 (95 %CI, 3.7–6.8) / 5.1 months (95 %CI, 2.5–7.8) with platinum rechallenge / lurbinectedin / others, respectively (p = 0.017). Median 2L-PFS was 4.6 (95 %CI, 3.9–7.2) / 2.7 (95 %CI, 1.6–3.9) / 2.2 months (95 %CI, 1.5–4.1) with platinum rechallenge / lurbinectedin / others, respectively (p = 0.025). DiscussionPlatinum-based rechallenge after a first-line CT-IO showed promising results despite particularly unfavorable characteristics within our real-word population. Lurbinectedin when used after IO demonstrated as low efficacy as other platinum-free regimens.