The mechanism of action of hepatitis B immunoglobulin (HBIG) for chronic hepatitis B (CHB) treatment is not fully understood. A clinical trial in Japan suggested that HBIG therapy might benefit patients with CHB.1 Lenvervimab, a recombinant monoclonal HBIG developed by GC Pharma (Yongin, South Korea), has been screened from an anti-HBs-enriched phage-display library cloned from hepatitis B vaccine-boosted human blood cells and was produced in Chinese hamster ovary cells.2-4.