Objectives: This report focuses on lurbinectedin activity and safety in a subgroup of small cell lung cancer (SCLC) patients from a Basket phase 2 study (Trigo et al. Lancet Oncology 2020;21:645-654) with chemotherapy-free interval (CTFI) ≥ 30 days. This pre-planned analysis was requested for obtaining regulatory approval of lurbinectedin in Switzerland., Materials and Methods: Patients with extensive-stage SCLC, no central nervous system (CNS) metastases, and disease progression after platinum-containing therapy were included. Topotecan data from a contemporary, randomized, controlled phase 3 study (ATLANTIS) were used as indirect external control in a matched patient population (n = 98 patients)., Results: Lurbinectedin showed a statistically significant higher overall response rate (ORR) by investigator assessment (IA) compared to topotecan subgroup (41.0 % vs. 25.5 %; p = 0.0382); higher ORR by Independent Review Committee (IRC) (33.7 % vs. 25.5 %); longer median duration of response (IA: 5.3 vs. 3.9 months; IRC: 5.1 vs. 4.3 months), and longer median overall survival (10.2 vs. 7.6 months). Grade ≥ 3 hematological abnormalities were remarkably lower with lurbinectedin: anemia 12.0 % vs. 54.1 %; leukopenia 30.1 % vs. 68.4 %; neutropenia 47.0 % vs. 75.5 %, and thrombocytopenia 6.0 % vs. 52.0 %. Febrile neutropenia was observed at a higher incidence with topotecan (6.1 % vs. 2.4 % with lurbinectedin) despite that the use of growth-colony stimulating factors was mandatory with topotecan., Conclusion: With the limitations of an indirect comparison, however using recent and comparable SCLC datasets, this post hoc analysis shows that SCLC patients with CTFI ≥ 30 days and no CNS metastases have a positive benefit/risk ratio with lurbinectedin, superior to that observed with topotecan., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Solange Peters received education grants,provided consultation, attended advisory boards and/or provided lecturesfor the following organizations, from whom she received honoraria (all fees to institution): consultation/advisory role: AbbVie, AiCME, Amgen, Arcus, AstraZeneca, Bayer, Beigene, BerGenBio, Biocartis, BioInvent, Blueprint Medicines, Boehringer Ingelheim, Bristol-Myers Squibb, Clovis, Daiichi Sankyo, Debiopharm, ecancer, Eli Lilly, Elsevier, F-Star, Fishawack, Foundation Medicine, Genzyme, Gilead, GSK, Hutchmed, Illumina, Imedex, IQVIA, Incyte, Ipsen, iTeos, Janssen,Medscape, Medtoday, Merck Sharp and Dohme, Merck Serono, Merrimack, Mirati, MJH Life Sciences, Nykode Therapeutics, Novartis, Novocure, OncologyEducation, Pharma Mar, Promontory Therapeutics, Peerview, Pfizer, Regeneron, RMEI, Roche/Genentech, RTP, Sanofi, Seattle Genetics, Takeda; Board of Director position: Galenica; Talk in a company’s organized public event: AiCME, AstraZeneca, Boehringer Ingelheim, Bristol-Myers Squibb, ecancer, Eli Lilly, Foundation Medicine, GSK, Illumina, Imedex, Ipsen, Medscape, Merck Sharp and Dohme, Mirati, MJH Life Sciences, Novartis, Peerview, Pfizer, Roche/Genentech, RTP, Sanofi, Taked; receipt of grants/research supports: Principal investigator in trials (institutional financial support for clinical trials) sponsored by Amgen, Arcus, AstraZeneca, Beigene, Bristol-Myers Squibb, GSK, iTeos, Merck Sharp and Dohme, Mirati, Pharma Mar, Promontory Therapeutics, Roche/Genentech, Seattle Genetics. Dr. José Trigo participated on data monitoring and safety board for this study. Dr. Alejandro Navarro received consulting fees from Boehringher Ingelheim,Takeda, Bristol Myers Squibb Foundation, Adium Pharma, Pfizer, Eczacibasi and Amgen; received payment for speaker’s bureau from Roche and AstraZeneca Spain; received payment for expert testimony from Oryzon Genomics, Medsir and Hengenix; and had support for attending meetings and/or travel from Boehringer Ingelheim, Pfizer and Roche. Dr. Luis Paz-Ares had grants or contracts from MSD, Astrazeneca, Pfize and BMS; received consulting fees from Lilly, MSD, Roche, Pharmamar, Merck, Astrazeneca, Novartis, Servier, Amgen, Pfizer, Sanofi, Bayer, BMS, Mirati, GSK, Janssen, Takeda and Daichii Sankyo; and received payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Astrazeneca, Janssen, Merck and Mirati. Dr. Christian Gohé received consulting fees from Boehringher, AstraZeneca, Novartis, Sanofi, and Takeda; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Novartis, Boehringher and AstraZeneca; payment for expert testimony from AstraZeneca; and had support for attending meetings and/or travel from Daichi. Drs. José Antonio López-Vilariño, Cristian Fernandez, Carmen Kahatt, Vicente Alfaro, Antonio Nieto and Ali Zeaiter received personal fees for salary as full time employees and stock ownership from Pharma Mar. Dr. Vivek Subbiah participated in Advisory Boards of Jazz Pharmaceuticals, Loxo Oncology/Eli Lilly, Regeneron, Relay Therapeutics, Pfizer, Roche, ABBVIE, Novartis, Bayer, Aadi Biosciences, Illumina, and Labcorp; and received payment for educational events from Clinical Care Options, LLC. Other authors declared no conflict of interest., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)