Savolitinib plus osimertinib in epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer with MET overexpression and/or amplification following disease progression on osimertinib: primary results from the phase II SAVANNAH study

Background: MET-based resistance following osimertinib treatment for epidermal growth factor receptor (EGFR)-mutated advanced non-small cell lung cancer (NSCLC) is common. We report the primary analysis of the phase II SAVANNAH study (NCT03778229) evaluating savolitinib plus osimertinib in this setting. Patients and methods: Patients had EGFR-mutated, advanced NSCLC with MET overexpression and/or amplification. MET cut-offs were initially MET immunohistochemistry (IHC)3+/≥50% (3+ intensity in ≥50% of tumor cells) and/or FISH5+ (≥5 MET gene copies or MET/chromosome 7 centromere ratio ≥2), and increased to MET IHC3+/≥90% and/or FISH10+ after a preliminary analysis. Patients received oral savolitinib [300 mg twice daily (b.i.d.) or once daily (o.d.), or 600 mg o.d.] plus osimertinib 80 mg o.d., or savolitinib 300 mg b.i.d. plus placebo. A primary endpoint was investigator-assessed objective response rate (ORR) in patients with progression on first-line osimertinib and MET IHC3+/≥90% and/or FISH10+ status receiving savolitinib 300 mg b.i.d. plus osimertinib (primary efficacy population). Safety was analyzed in all patients receiving savolitinib plus osimertinib. Results: Of the 365 patients treated, 341 received savolitinib plus osimertinib, with 80 of these included in the primary efficacy population. Investigator-assessed confirmed ORR in the primary efficacy population was 56.3% [95% confidence interval (CI) 44.7% to 67.3%]; the median duration of response (mDoR) was 7.1 months (95% CI 5.6-9.6 months); the median progression-free survival (PFS) was 7.4 months (95% CI 5.5-7.6 months). Blinded independent central review was consistent: confirmed ORR 55.0% (95% CI 43.5% to 66.2%); mDoR 9.9 months (95% CI 6.0-13.7 months); median PFS 7.5 months (95% CI 6.4-11.3 months). The most common any grade adverse events in patients receiving savolitinib plus osimertinib were peripheral edema (46.0%), nausea (40.5%), and diarrhea (23.2%). Conclusions: Savolitinib 300 mg b.i.d. plus osimertinib demonstrated high, clinically meaningful and durable responses in patients with EGFR-mutated, advanced NSCLC with MET IHC3+/≥90% and/or FISH10+ status following progression on first-line osimertinib. The combination was well tolerated and may provide a new oral targeted treatment approach in this setting.