Treatment of advanced lung adenocarcinoma with EGFR L833V/H835L compound mutations using furmonertinib: two case reports and literature review

Background Lung cancer remains the leading cause of cancer-related mortality worldwide. With advancements in molecularly targeted therapies, Epidermal growth factor receptor (EGFR) mutations have emerged as critical therapeutic targets in advanced lung adenocarcinoma. However, the EGFR p.L833V/p.H835L compound mutations are relatively uncommon, and their clinical characteristics and therapeutic response to EGFR tyrosine kinase inhibitors (TKIs) remain poorly defined. Case presentation This study reports two cases of advanced lung adenocarcinoma harboring the EGFR p.L833V/p.H835L compound mutation, both treated with furmonertinib. Case 1 was a 62-year-old male, and Case 2 was a 61-year-old female, both diagnosed through tissue biopsy and next-generation sequencing (NGS). Following treatment, both patients achieved partial response (PR), with progression-free survival (PFS) of 29 months and not available (NA, >12 months), respectively, demonstrating good tolerability. Results Furmonertinib appears to be an effective treatment for advanced lung adenocarcinoma with EGFR p.L833V/p.H835L compound mutations. Conclusion This study further supports the therapeutic potential of furmonertinib in EGFR-mutant lung cancer.