COMPOSIT study: evaluating osimertinib combination with targeted therapies in EGFR-mutated non-small cell lung cancer

The emergence of diverse resistance mechanisms after osimertinib therapy, including on-target epidermal growth factor receptor (EGFR) mutations and off-target alterations, warrants investigation of novel therapeutics to overcome these challenges and improve patient outcomes.

COMPOSIT was a French, retrospective, multicenter, cohort study of the effectiveness and tolerability of osimertinib in combination with other targeted therapies in patients with advanced EGFR-mutant (EGFRm) non-small cell lung cancer (NSCLC) who harbored other oncogenic drivers as primary or acquired resistance mechanisms. Real-world progression-free survival (rwPFS), overall survival (OS), and objective response rate (ORR) were the primary endpoints.

The study included 61 patients (63.9% women; median age, 61 years). Chemotherapy was administered to 26 patients (42.6%) before the combinations. The most frequently targeted resistance mechanisms were MET amplification (n = 40) and BRAF alterations (n = 11). Sixteen combinations of osimertinib with other targeted therapies were reported. Overall (except for 10 patients in clinical trials), median rwPFS and OS were 3.9 (95% CI, 2.9-5.2) and 9.8 months (95% CI, 6.8-14.8). Best ORR (n = 54) was 50% (95% CI, 33.0-72.8). In patients with MET amplification (n = 29), median rwPFS and OS were 4.9 (95% CI, 2.9-7.2) and 8.6 months (95% CI, 5.3-21.6). Grade ≥3 adverse events occurred in 15 patients (24.6%). No deaths were related to treatment.

Combinations of osimertinib with other targeted therapies appeared to be feasible and safe and may offer clinical benefit to overcome resistance to osimertinib in EGFRm NSCLC, especially in patients with MET amplification.