PATIENTS AND METHODS: This analysis included patients with treatment-naive, EGFR-mutant advanced NSCLC randomized to amivantamab-lazertinib (n = 429) or osimertinib (n = 429) in MARIPOSA. Pathogenic alterations were identified by next-generation sequencing (NGS) of baseline blood ctDNA with Guardant360 CDx. Ex19del and L858R ctDNA in blood was analyzed at baseline and cycle 3 day 1 (C3D1) with Biodesix droplet digital polymerase chain reaction (ddPCR).

RESULTS: Baseline ctDNA for NGS of pathogenic alterations was available for 636 patients (amivantamab-lazertinib, n = 320; osimertinib, n = 316). Amivantamab-lazertinib improved median PFS (mPFS) versus osimertinib for patients with TP53 co-mutations {18.2 versus 12.9 months; HR 0.65 [95% confidence interval (CI) 0.48-0.87]; P = 0.003} and for patients with wild-type TP53 [22.1 versus 19.9 months; HR 0.75 (95% CI 0.52-1.07)]. In patients with EGFR-mutant, ddPCR-detectable baseline ctDNA, amivantamab-lazertinib significantly prolonged mPFS versus osimertinib [20.3 versus 14.8 months; HR 0.68 (95% CI 0.53-0.86); P = 0.002]. Amivantamab-lazertinib significantly improved mPFS versus osimertinib in patients without ctDNA clearance at C3D1 [16.5 versus 9.1 months; HR 0.49 (95% CI 0.27-0.87); P = 0.015] and with clearance [24.0 versus 16.5 months; HR 0.64 (95% CI 0.48-0.87); P = 0.004]. Amivantamab-lazertinib significantly prolonged mPFS versus osimertinib among randomized patients with [18.2 versus 11.0 months; HR 0.58 (95% CI 0.37-0.91); P = 0.017] and without baseline liver metastases [24.0 versus 18.3 months; HR 0.74 (95% CI 0.60-0.91); P = 0.004].

PATIENTS AND METHODS: Patients with EGFR-mutated advanced NSCLC who progressed following osimertinib and platinum-based chemotherapy were randomized 1:1 to receive subcutaneous or intravenous amivantamab, both combined with lazertinib. Co-primary pharmacokinetic noninferiority endpoints were trough concentrations (Ctrough; on cycle-2-day-1 or cycle-4-day-1) and cycle-2 area under the curve (AUCD1-D15). Key secondary endpoints were objective response rate (ORR) and progression-free survival (PFS). Overall survival (OS) was a predefined exploratory endpoint.

RESULTS: Overall, 418 patients underwent randomization (subcutaneous group, n=206; intravenous group, n=212). Geometric mean ratios of Ctrough for subcutaneous to intravenous amivantamab were 1.15 (90% CI, 1.04-1.26) at cycle-2-day-1 and 1.42 (90% CI, 1.27-1.61) at cycle-4-day-1; the cycle-2 AUCD1-D15 was 1.03 (90% CI, 0.98-1.09). ORR was 30% in the subcutaneous and 33% in the intravenous group; median PFS was 6.1 and 4.3 months, respectively. OS was significantly longer in the subcutaneous versus intravenous group (hazard ratio for death, 0.62; 95% CI, 0.42-0.92; nominal P=0.02). Fewer patients in the subcutaneous group experienced infusion-related reactions (13% versus 66%) and venous thromboembolism (9% versus 14%) versus the intravenous group. Median administration time for first infusion was reduced to 4.8 minutes (range, 0-18) for subcutaneous amivantamab from 5 hours (range, 0.2-9.9) for intravenous amivantamab. During cycle-1-day-1, 85% and 52% of patients in the subcutaneous and intravenous groups, respectively, considered treatment convenient; end-of-treatment rates were 85% and 35%, respectively.