577P - A study of the efficacy and safety of amivantamab in EGFR exon 20 insertion (E20I) mutations in NSCLC

Background

In non-small cell lung cancer (NSCLC), the epidermal growth factor receptor (EGFR) mutation is a representative oncogenic driver mutation. Only about 12% of EGFR mutation patients have the exon 20 insertion mutation, which is the third most frequent mutation among EGFR mutation NSCLC. Amivantamab, an epidermal growth factor receptor (EGFR) and MET proto-oncogene, receptor tyrosine kinase (MET) bispecific antibody, was approved for non-small cell lung cancer (NSCLC) patients with the EGFR exon 20 insertion mutation. In this study, we described the real-world, single-center efficacy and safety data of amivantamab in EGFR exon 20 insertion (E20I) mutation patients.

Methods

This study included metastatic NSCLC patients with EGFR E20I mutations. From January 2018 to June 2022, patients with EGFR E20I mutations who were treated with amivantamab were analyzed at Samsung Medical Center as part of the clinical trial or the EAP. We collected the patients’ characteristics and analyzed PFS and OS stratified by PD-L1 expression status, co-mutation such as TP53, and metastasis sites.

Results

A total of 42 patients were analyzed, of which 16 patients were enrolled in the phase 1 study, and 26 patients received amivantamab through EAP. There were 14 (33%) patients with partial remission, 18 (43%) patients with stable disease, and 10 (24%) patients with disease progression. The objective response rate (ORR) was 33%, and the disease control rate (DCR) was 76%. PFS was analyzed by dividing the near and far loop for 31 patients whose mutation location was known. The two groups had no statistically significant difference in PFS (median 11.8 mo [range, 2.3-21.3 mo] vs. 11.3 mo [3.4-19.2]; p=0.69). For 29 patients with TP53 mutation data, there was no significant difference in PFS between the two groups (median 5.9 mo [0-18.0 mo] vs. 12.6 mo [6.9-18.3]; p=0.11) When analyzing PFS in 37 patients with PD-L1 expression data, PD-L1 (+) patients showed a poor prognosis (median 11.3 mo [5.0-17.1 mo] vs. 19.5 mo [5.3-33.7 mo]; p=0.04; hazard ratio [HR]=0.44 [0.20-0.98]).

Conclusions

The efficacy of amivantamab was confirmed for the real-world population for EGFR E20I-mutated NSCLC. PD-L1 status could be a poor predictive factor, which should be further validated.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

M. Ahn: Financial Interests, Personal, Advisory Board: AstraZeneca, Takeda, MSD, Yuhan, Amgen, Alpha Pharmaceutical, Janssen, BMS, Roche, Daichi Sankyo, Merck, Boronoi. S. Lee: Financial Interests, Personal, Advisory Board: AstraZeneca/MedImmune, Roche, Merck, Pfizer, Lilly, BMS/Ono, Takeda, Janssen, IMBdx; Financial Interests, Personal, Invited Speaker: AstraZeneca/MedImmune, Roche, Merck, Lilly, Amgen; Financial Interests, Institutional, Research Grant: Merck, AstraZeneca, Lunit. All other authors have declared no conflicts of interest.