An In-Depth Pharmacological and Clinical Review of OM-85 (Broncho-Vaxom): An Immunomodulatory Bacterial Lysate

Executive Summary

OM-85 is a complex biologic drug product, classified as an immunomodulatory bacterial lysate, with a long and extensive history of clinical use spanning over four decades. Marketed globally under the primary trade name Broncho-Vaxom®, it is approved in 64 countries for the prophylaxis of recurrent respiratory tract infections (RTIs) in both pediatric and adult populations. Its composition is a standardized, lyophilized extract derived from the alkaline lysis of 21 strains of eight bacterial species commonly implicated in respiratory disease. This unique composition provides a mixture of pathogen-associated molecular patterns (PAMPs) that engage the host immune system in a multifaceted manner.

The mechanism of action of OM-85 is distinct from both traditional vaccines and antibiotics. Upon oral administration, it interacts with the gut-associated lymphoid tissue (GALT), initiating a cascade of immune events via the gut-lung axis. This process involves the activation of both the innate and adaptive immune systems, leading to the maturation of dendritic cells, a balanced T-helper cell response (Th1/Th2/Treg), and a significant increase in protective antibodies, particularly secretory IgA (sIgA), at the respiratory mucosa. Recent research has further elucidated novel, host-directed antiviral properties, including the downregulation of cellular receptors like ACE2, which are critical for viral entry, positioning OM-85 as a potential broad-spectrum antiviral agent.