Study 1: COSELA Prior to Etoposide, Carboplatin, and Atezolizumab (E/P/A)
Patients with newly diagnosed ES-SCLC not previously treated with chemotherapy
Study 1 (G1T28-05) was a randomized (1:1), double-blind, placebo-controlled study of COSELA or placebo administered prior to treatment with etoposide, carboplatin, and atezolizumab (E/P/A) for patients with newly diagnosed ES-SCLC not previously treated with chemotherapy.
A total of 107 patients were randomized to receive COSELA (n=54) or placebo (n=53) prior to administration of E/P/A; patients were stratified by Eastern Cooperative Oncology Group (ECOG) performance status (0 to 1 vs 2) and the presence of brain metastases. Carboplatin (AUC 5) and atezolizumab (1200 mg) were administered on Day 1 and etoposide (100 mg/m2) and COSELA (240 mg/m2) or placebo were administered on Days 1, 2, and 3 of a 21-day cycle for a maximum of 4 cycles (induction). After induction, maintenance atezolizumab (1200 mg) monotherapy on Day 1 of a 21-day cycle continued until disease progression or unacceptable toxicity. COSELA was not administered during maintenance.
The study population characteristics were: median age 64 years (range: 45 to 83); 70% male; 97% white; 14% ECOG performance status 2; 28% with a history of brain metastases; 38% current smokers; 46% lactate dehydrogenase (LDH) >ULN.
The mean relative dose intensities (RDIs) for E/P/A in patients receiving COSELA were 93%, 95%, and 93%, respectively. The mean RDIs for E/P/A in patients receiving placebo were 88%, 89%, and 91%, respectively. Dose reductions of carboplatin occurred in 2% of patients receiving COSELA and in 25% of patients receiving placebo; dose reductions of etoposide occurred in 6% of patients receiving COSELA and in 26% of patients receiving placebo. No dose reduction was allowed for COSELA or atezolizumab.
The study demonstrated a statistically significantly shorter duration of severe neutropenia (DSN) in Cycle 1 (0 vs 4 days) and a lower proportion of patients with severe neutropenia (SN) (2% vs 49%) in patients receiving COSELA compared with placebo (Table 5). Nineteen percent of patients receiving COSELA had Grade 3 or 4 decreased hemoglobin compared with 28% of patients receiving placebo (adjusted relative risk 0.663 [95% CI: 0.336, 1.310]). The rate of RBC transfusions over time was 1.7/100 weeks for patients receiving COSELA and 2.6/100 weeks for patients receiving placebo (adjusted relative risk was not estimable). Six percent of patients receiving COSELA received erythropoiesis-stimulating agents (ESAs) compared with 11% of patients receiving placebo (adjusted relative risk 0.529 [95% CI: 0.145, 1.927]).