Real-world treatment patterns and outcomes among patients with advanced NSCLC treated with amivantamab.

e20646 Background: Among patients with non-small cell lung cancer (NSCLC), ~19-24% harbor epidermal growth factor receptor mutations (EGFRm). Amivantamab (AMI) was approved by the US Food and Drug Administration on 5/21/2021 for second-line (2L) patients with EGFR exon 20 insertions (Exon20Ins) advanced NSCLC who progressed after platinum-based chemotherapy (PBC), on 3/1/2024 for first-line (1L) EGFR Exon20Ins, and for 1L (8/20/2024) and 2L (9/19/2024) EGFR exon 19 deletion and L858R. Immunotherapy (IO) monotherapy (mono) has limited effectiveness in treating EGFRm advanced NSCLC and fails to add clinical benefit when used with PBC, yet increases toxicity risk. This study evaluates real-world treatment patterns and outcomes among patients receiving AMI. Methods: Komodo Research Data closed claims (1/1/2016-10/31/2023) were used to analyze adults with a lung cancer diagnosis (ICD-10-CM: C34) initiated on AMI on/after 5/21/2021 in 2L or later (2L+) for advanced NSCLC. Baseline brain/cerebral meninges (CNS) metastases were identified based on ≥1 diagnosis (ICD-10-CM: C79.3) in the continuous eligibility period before 1L initiation. Treatment patterns, including prior IO use with/without PBC, were described for patients initiating AMI in 2L, third-line (3L), and fourth-or-later line (4L+). Time to next treatment or death (TTNT-D) was evaluated for patients initiating AMI mono in 2L after PBC using Kaplan-Meier survival analysis. Results: A total of 126 patients initiated AMI in 2L+ (mean age: 60.2 years; 63.5% female), with 65 (51.6%) receiving AMI in 2L, 41 (32.5%) in 3L, and 20 (15.9%) in 4L+. Baseline CNS metastases were observed in 35.4% of 2L AMI patients (3L: 22.0%; 4L+: 35.0%). For patients initiating AMI in 2L, median follow-up duration was 6.5 months (3L: 5.9; 4L+: 6.8) [Table 1]. AMI mono was used in 92.3% of 2L patients (3L: 73.2%; 4L+: 80.0%). In combination therapy, AMI with osimertinib was most commonly used (2L: 4.6%, 3L: 19.5%; 4L+: 15.0%). Prior PBC use was observed in 83.1% of 2L AMI patients (3L: 100.0%; 4L+: 100.0%); 60.0% had prior IO use (3L: 63.4%; 4L+: 85.0%), including 53.8% IO+PBC (3L: 53.7%; 4L+: 60.0%) and 3.1% IO mono (3L: 4.9%; 4L+: 20.0%). Among 51 patients initiating AMI mono in 2L after PBC, median TTNT-D was 10.1 months. Conclusions: Among patients receiving AMI in 2L+, most initiated AMI mono after PBC, consistent with the FDA approval at the time of this study. Over half of patients had prior IO use, exposing them to suboptimal treatment and avoidable toxicity risk. Among patients receiving AMI mono in 2L following PBC, median TTNT-D was similar to median progression-free survival observed in clinical trials. 2L(n = 65) 3L(n = 41) 4L+(n = 20) Median follow-up, months 6.5 5.9 6.8 AMI mono, % 92.3 73.2 80.0 AMI combination, % 7.7 26.8 20.0 With osimertinib 4.6 19.5 15.0 Other combinations 3.1 7.3 5.0 Prior PBC use, % 83.1 100.0 100.0 Prior IO use, % 60.0 63.4 85.0 With PBC 53.8 53.7 60.0 Mono 3.1 4.9 20.0