570P - First-line osimertinib for patients with advanced NSCLC harboring EGFR mutations: A real-world study

Background

Osimertinib is the standard of care for the first-line treatment of advanced NSCLC (aNSCLC) patients (pts) with epidermal growth factor receptor (EGFR) activating mutations. Limited Chinese patients’ data in real-world setting are available regarding the effectiveness of osimertinib in EGFRm aNSCLC, especially in patients harboring uncommon EGFR mutations.

Methods

Patients treated with first-line osimertinib were retrospectively collected from 11 hospitals in China between March 25, 2017 and December 31, 2022. Mutations were categorized as EGFR activating mutations (19del/21L858R; cohort 1) and uncommon mutations (G719X, L861Q, S768I, 20ins, de novo T790M; cohort 2). Patient characteristics, progression-free survival (PFS), time to progression (TTP), objective response rate (ORR), and disease control rate (DCR) were analyzed.

Results

A total of 385 patients with stage IV NSCLC were included, 308 pts in cohort 1 and 77 pts in cohort 2. The median age was 59 years, 214 (55.6%) were female, 350 (90.9%) were adenocarcinoma, and 141 (36.6%) patients had documented brain metastases (35 patients received whole-brain radiotherapy). In cohort 1, the median follow-up was 32.8 months and mPFS was 20.8 months (19del subgroup: 22.7 months; 21L858R subgroup: 14.8 months). For patients with/without documented brain metastases, mPFS was 15.6 months and 23.4 months, respectively. mTTP was 21.5 months for all patients. ORR was 75.6%, including 3 patients with CR and 230 patients with PR. DCR was 94.2%. In cohort 2, ORR was 64.9% (50 patients with SD) and DCR was 93.5%. with a median follow-up of 8.3 months, both mPFS and mTTP were 7.3 months. No new safety signals were observed. Table: 570P

Conclusions

The result is consistent with FLAURA study for patients with EGFR-activating mutation. Osimeritinib showed clinical activity in patients with EGFR uncommon mutations as first-line treatment.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.