Abstract 570P
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
| Cohort 1 (19del, 21L858R) | Cohort 2 (G719X, L861Q, S768I, 20ins, de novo T790M) | |
| n (%) | 308 (80%) | 77 (20%) |
| CRPRSDPD | 3 (0.9%)230 (74.7%)57 (18.5%)18 (5.9%) | 0 (0%)50 (64.9%)22 (28.6%)5 (6.5%) |
| ORR (%) | 75.6% | 64.9% |
| DCR (%) | 94.2% | 93.5% |
| mPFS (month) | 20.8m | 7.3m |
| mTTP(month) | 21.5m | 7.3m |
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.
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