Trilaciclib, in comparison to placebo plus carboplatin, etoposide, ± atezolizumab (PEA), has shown significant reductions in incidence of severe neutropenia (SN) among patients with extensive-stage small cell lung cancer (ES-SCLC). Despite these findings, real-world utility remains limited. A single-center quasi-experimental study compared trilaciclib + PEA (PEAT) versus PEA in ES-SCLC patients. The study period ranged from April 1, 2021 to July 31, 2022, for the PEAT recipients and February 1, 2020, to February 28, 2021, for PEA recipients. The primary endpoint evaluated was incidence of SN after cycle 1 and during the treatment period. Secondary endpoints included measures related to myelopreservation and patient outcomes. Among 34 PEAT and 44 PEA patients, baseline characteristics were similar, except for a higher median age (69 vs 64years) and more males (64.7% vs 38.6%) in the PEAT cohort. The PEAT cohort exhibited a lower SN rate (3%) versus the PEA cohort (18%), with statistical significance demonstrated on multivariate analysis (p = 0.015). Additionally, the PEAT cohort also demonstrated significant reductions in red blood cell transfusion requirements (3% vs 23%; p = 0.02), grade 3-4 anemia (6% vs 25%; p = 0.03), and grade 3-4 thrombocytopenia (0% vs 11%, p = 0.045). Trilaciclib, in combination with PEA, demonstrated an improvement in the safety profile without compromising survival outcomes in ES-SCLC patients. These findings underscore the potential benefits of incorporating trilaciclib in real-world clinical settings for enhanced patient care.