Amivantamab-Induced Capillary Leak Syndrome Successfully Treated With Intravenous Immunoglobulin Administration: Case Report

Capillary leak syndrome (CLS) is a rare but potentially life-threatening condition characterized by generalized edema, hypotension, and hypoalbuminemia. Amivantamab has recently been approved for the management of metastatic NSCLC. Although peripheral edema has been reported with amivantamab, CLS has not previously been described in association with this treatment. Herein, we report a case of CLS attributed to amivantamab that resolved after drug discontinuation and a short course of high-dose intravenous immunoglobulin administration. The anti-inflammatory, neutralizing, and antibody clearance-accelerating effects of intravenous immunoglobulin may explain their potential efficacy in treating amivantamab-induced CLS. As therapeutic antibodies become increasingly used, CLS may be encountered more frequently. A better understanding of its pathophysiologic characteristics is therefore essential to develop effective treatments and preventive strategies, ultimately minimizing its consequences on patient outcomes.