Outcomes with trilaciclib versus granulocyte colony stimulating factor regarding chemotherapy-associated adverse events, dose reductions, and subsequent therapies in small cell lung cancer.

e20116 Background: Trilaciclib is a CDK4/6 inhibitor approved for extensive-stage small cell lung cancer (ES-SCLC) as a supportive care medication with platinum-based chemotherapy. Myelosuppression from chemotherapy can result in severe infections, dose reductions, treatment delays, hospitalizations, and may impact future trial eligibility if count recovery is hindered. Here, we seek to understand the impact of trilaciclib, granulocyte colony stimulating factor (GCSF), or the combination on myelosuppression and related outcomes in SCLC. Methods: A retrospective chart review was conducted on patients diagnosed with ES-SCLC who received first line therapy and supportive care medications (GCSF and/or trilaciclib) in the Indiana University Health System from January 2018 to August 2024. Those who did not receive these medications were included as a control. Demographics, treatment, AEs, and related outcomes outlined in Table 1 were recorded. AEs graded per CTCAEv5.0. Estimated hospitalization costs were calculated by Medicare reimbursement rates. Labs performed 3 weeks after induction chemotherapy completion were assessed. Standard cut-offs for clinical trials (Hgb ≥9, ANC ≥1500, and Plt ≥100K) were applied to assess eligibility for a hypothetical trial. Results: Sixty-four patients who received first-line platinum-based regimens were included. Twenty-three (35.9%) received GCSF only, 12 (18.8%) received trilaciclib only, 13 (20.3%) received both trilaciclib and GCSF, and 16 (25%) received neither drug. Conclusions: Compared to GCSF, the use of trilaciclib in patients with SCLC results in shorter length of stay and fewer chemotherapy dose reductions. Trends towards reduced cost of hospitalizations, G3/4 anemia and febrile neutropenia were noted, but limited by sample size. Labs performed shortly after completion of induction chemotherapy showed a trend to improve hematologic parameters which can potentially affect patient eligibility for subsequent clinical trials. This early benefit is particularly helpful in patients with platinum-resistant SCLC. Cohorts by use of supportive care medications. Variable OverallN=64 GCSFN=23 TrilaciclibN=12 GCSF + TrilaciclibN=13 NoneN=16 P Value Anemia G3/4 21 (32.8%) 7 (30.4%) 2 (16.7%) 4 (30.8%) 8 (50%) .316 Neutropenia G3/4 22 (34.4%) 9 (39.1%) 3 (25%) 2 (15.4%) 8 (50%) .223 Febrile neutropenia 6 (9.4%) 4 (17.4%) 0 (0%) 0 (0%) 2 (12.5%) .274 Days hospitalized 2.6 ± 5.6 4.6 ± 6.8 0.4 ± 1.2 0.3 ± 1.1 3.2 ± 6.8 .046 Cost of hospitalization $3,643 ± 7,858 $5,101 ± 7,094 $1,084 ± 2,602 $394 ± 1,419 $6,094 ± 12,445 .07 Received dose reduction 33 (51.6%) 15 (65.2%) 2 (16.7%) 5 (38.5%) 11 (68.8%) .016 Post-chemotherapy potential trial eligibility 33 (59.9%) 10 (47.6%) 8 (72.7%) 10 (76.9%) 5 (35.7%) .09