Anti-GM-CSF monoclonal antibody Treatment of chronic myelomonocytic leukemia Treatment of COVID-19

Granulocyte-macrophage colony-stimulating factor (GM-CSF) plays a central role in immune response; it is a key mediator of inflammation and tissue injury. Lenzilumab, a humanized anti-GM-CSF monoclonal antibody directly binds to GM-CSF and prevents signaling through its receptor; it is being evaluated for its efficacy and safety in treating COVID-19 as well as several inflammatory and autoimmune conditions. The purpose of this review was to summarize available data on the clinical safety and efficacy of lenzilumab for the treatment of inflammatory and autoimmune diseases as well as COVID-19. In a phase II study of patients with chronic myelomonocytic leukemia, lenzilumab was associated with a durable clinical benefit in a third of participants. In patients with inadequately controlled asthma, lenzilumab improved FEV₁ in eosinophilic asthmatics, but did not improve asthma control. In patients with severe COVID-19 pneumonia, lenzilumab significantly improved survival without ventilation over and above current supportive treatments, including remdesivir and corticosteroids. Among these patients, those with baseline C-reactive protein (CRP) values less than 150 mg/L derived the greatest benefit from lenzilumab. Lenzilumab was safe and well tolerated. In the clinical trials conducted to date, no deaths, drug-related serious adverse events or withdrawals due to adverse events were noted.