Exceptional response to furmonertinib in lung adenocarcinoma harboring HER2 exon 20 insertion mutation: a case report

This case provides the first clinical evidence of furmonertinib's activity against HER2 ex20ins mutations. The structural homology between HER2 p.Y772_A775dup and EGFR exon 20 "near-loop" insertions may facilitate TKI binding. Furmonertinib emerges as a potential, cost-effective oral therapeutic alternative for this patient population, especially when standard therapies are not feasible, warranting further prospective investigation.