Abstract 7218: Preventive use of trilaciclib in Chinese patient with extensive-stage small cell lung cancer (ES-SCLC) receiving chemotherapy: A multi-center, single-arm, observational real-world study

Abstract Background: Extensive-stage small cell lung cancer (ES-SCLC) is a highly aggressive disease characterized by rapid progression and development of extensive metastases. Standard chemotherapy-based regimens for ES-SCLC often lead to myelosuppression, compromising medication compliance and prognosis. Trilaciclib is a CDK4/6 inhibitor, approved by NMPA in 2022 to decrease the incidence of chemotherapy-induced myelosuppression (CIM) in adult with ES-SCLC. This study aims to evaluate the efficacy and safety of preventive use of trilaciclib prior chemotherapy in Chinese ES-SCLC population under real-world settings. Methods: ES-SCLC patients suitable for combined treatment of trilaciclib and chemotherapy were enrolled in this study. Eligible participant received 240 mg/m2 of trilaciclib IV 4 h prior chemotherapy. The primary endpoint was the incidence rate of severe neutropenia (SN). The secondary endpoints included the occurrence of grade 3/4 hematologic adverse events (HAEs), administration rate of G-CSF and ESA, safety, and anti-tumor efficacy of chemotherapy. Results: A total of 201 ES-SCLC patients receiving at least one dose of trilaciclib combined with chemotherapy were included from 60 centers in China during March 10 2023 to August 10 2024, with median age of 65 (58, 71). Metastases occurred in 90.0% of the subjects at baseline, in which brain metastases accounted for 16%. 92.5% of the patients adopted platinum plus etoposide (E/P) regimen. The mean number of completed chemo-cycle was 3.0 (1.4). In Cycle 1, 1 case (0.6%) of SN occurred in patient receiving second-line (2L) treatment with E/P therapy. Grade 3/4 HAEs were reported in 5.4% of the patients in Cycle 1, including neutropenia (3.6%), anemia (1.2%) and thrombocytopenia (1.8%). During the whole treating period, a total of 5 cases (2.6%) of SN occurred, 4 of which received 2L treatment with E/P, while the remaining one received first-line cis-platinum therapy. 17.5% participants experienced grade 3/4 HAEs during the study, in which neutropenia, anemia and thrombocytopenia accounted for 8.2%, 9.3% and 3.1%, respectively. G-CSF and ESA were used in 2.6% and 1.0% of the patients. As for safety, grade ≥3 AEs were reported in 20.9% of the participants. No AEs-related treatment discontinuation happened. No serious AEs and death occurred. Among 48 patients included into tumor response analysis, the best response to chemotherapy was CR (8.3%), PR (43.8%), SD (39.6%) and PD (8.3%). The objective response rate (ORR) and disease control rate (DCR) reached 52.1% and 91.7%, respectively. Conclusions: Prophylactic administration of trilaciclib (240 mg/m2) prior chemotherapy exhibits superior myeloprotective effect and were well-tolerated in Chinese ES-SCLC population, providing evidence for clinical benefit of trilaciclib as a myelo-protectant. Citation Format: Ying Liu, Jianqiang Bi, Jianxin Chen, Meifang Chen, Xuesong Chen, Yongxing chen, Yinghua Ji, Yujie Jiang, Lu Li, Qin Liao, Sheng Lin, Jie Liu, Yi Liu, Yu Liu, Zhaoting Meng, Zhuqing Mu, Yunxiang Qi, Yanhong Shang, Ling Xu, Shufeng Xu, Lu Zheng, Jin Zhou, Ying Cheng. Preventive use of trilaciclib in Chinese patient with extensive-stage small cell lung cancer (ES-SCLC) receiving chemotherapy: A multi-center, single-arm, observational real-world study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7218.