EGFR L858R + EGFR exon 19 deletion

She was initially treated with icotinib for an EGFR exon 21 L858R mutation but the disease progressed after 4 months. CONCLUSIONS As a single case with multiple confounders, this study generates hypotheses but does not confirm efficacy. Further investigation is required to validate high-dose furmonertinib for NSCLC with EGFR exon 14 missense mutations.

P1/2, N=40, Recruiting, Sichuan University | Trial completion date: Feb 2026 --> Dec 2028 | Trial primary completion date: Dec 2025 --> Dec 2027

P2, N=125, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Mar 2026 --> Mar 2027

For classical EGFR mutations such as exon 19 deletion and exon 21 L858R mutation, combination strategies in the first-line setting, based on the results of the MARIPOSA (lazertinib and amivantamab) and FLAURA 2 (platinum-based doublet chemotherapy and osimertinib) trials, provide promising outcomes. Optimising the treatment sequence in advanced EGFR-mutated NSCLC is crucial to ensure the best survival outcomes along with the best treatment tolerance and quality of life. Predictive biomarkers are strongly needed as well as biomarker-based escalation and de-escalation clinical trials.

HLA-A subtypes did not correlate with prognostic outcomes in sensitized EGFR mutations. The diverse binding affinity with EGFR peptides was not translated into the TIME patterns.

This study supports the effectiveness and tolerable safety profile of osimertinib as first-line treatment for patients with aNSCLC in a real-world setting. Exon 19 deletion appears to be a strong predictor of greater effectiveness in patients with aNSCLC.

P2, N=125, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Mar 2025 --> Mar 2026

Subgroup analyses also showed similar tendency that 21 L858R had more clinical benefit compared to 19 Del no matter whether IO monotherapy or IO combination. For advanced EGFR mutant NSCLC patients, 21 L858R had superior IO efficacy compared with 19 Del.

This case demonstrates the efficacy of osimertinib for rare EGFR mutations, aligning with literature suggesting its potential for managing such variants. Although large-scale trials are impractical due to the rarity of these mutations, this report adds valuable evidence supporting osimertinib's use, highlighting the need for comprehensive genomic profiling in NSCLC.

Conclusions Our study reveals a high frequency of occult EGFR mutations (Exon 19 deletion and Exon 21 L858R mutation) in non-small cell lung cancer (NSCLC) patients, particularly among male smokers and female non-smokers. These findings emphasize the importance of routine EGFR mutation testing to identify patients who may benefit from targeted therapies, ultimately improving treatment outcomes.

This retrospective study used a nationwide electronic health record-derived deidentified database to select adult patients with advanced nonsquamous NSCLC, evidence of EGFR exon 19 deletion or L858R mutation, and ECOG performance status of 0-2 who initiated platinum-containing chemotherapy, with or without concomitant immunotherapy, from 1-January-2011 to 30-June-2020 following receipt of any EGFR TKI as first-line therapy or, alternatively, a first- or second-generation EGFR TKI (erlotinib, afatinib, gefitinib, dacomitinib) as first-line therapy followed by the third-generation EGFR TKI osimertinib as second-line therapy. Median OS was 10.3 months (95% CI, 8.1-13.9) from pemetrexed-platinum initiation and 12.4 months (95% CI, 10.2-15.2) from platinum initiation; 12-month survival rates were 48% and 51%, respectively; 260 patients (84%) had died by the end of the study. The suboptimal survival outcomes recorded in this study demonstrate the unmet need to identify more effective subsequent treatment regimens for patients with EGFR-mutated advanced nonsquamous NSCLC after EGFR TKI resistance develops.

P2, N=125, Active, not recruiting, National Cancer Institute (NCI)