Amivantamab Monotherapy for Lung Adenocarcinoma With Leptomeningeal Seeding: A Case Report.

Non-small cell lung cancer (NSCLC) is characterised by a number of driver mutations, among which epidermal growth factor receptor (EGFR) exon 20 insertion mutations are associated with poor prognosis due to structural alterations that confer resistance to conventional tyrosine kinase inhibitors (TKIs). Recently, amivantamab, a fully human bispecific antibody targeting EGFR and MET, has demonstrated promising efficacy in patients with EGFR exon 20 insertion mutations. However, its therapeutic activity against central nervous system metastases remains uncertain. Here, we report a case of a patient with NSCLC who developed leptomeningeal seeding (LMS) after the failure of first-line therapy and showed a marked clinical and radiologic response to amivantamab monotherapy.