OM-85, a Bacterial Lysate, Reduces Pulmonary Nodule Malignant Probability: A Retrospective Study

Area of Science:

• Immunology
• Pulmonology
• Pharmacology

Background:

• Current pulmonary nodule management relies on CT follow-up without early intervention.
• High-risk pulmonary nodules require novel therapeutic strategies for improved patient outcomes.
• Chronic bronchitis patients with pulmonary nodules face increased risks of malignancy and disease progression.

Purpose of the Study:

• To investigate the efficacy of OM-85, a bacterial lysate, in treating high-risk pulmonary nodules in chronic bronchitis patients.
• To evaluate OM-85's impact on nodule size, malignancy risk, and disease progression.
• To explore the immunological mechanisms underlying OM-85's therapeutic effects.

Main Methods:

• Retrospective study comparing OM-85 treatment group (72 patients) with a matched control group (90 patients).
• Primary endpoint: reduced high-risk ground glass nodule size assessed by thin-layer CT scans.
• Immune cell analysis using flow cytometry, multiplex immunofluorescence (mIF), and scRNA-seq.

Main Results:

• OM-85 significantly reduced lung nodule diameter (p=0.031), malignancy risk (p=0.003), and disease progression (p=0.0091).
• Treatment effects were more pronounced in older patients (>65 years) and those with longer follow-up (>200 days).
• OM-85 increased the proportion of natural killer (NK) cells in peripheral blood and pulmonary nodules (p=0.0003).

Conclusions:

• OM-85 effectively reduces high-risk pulmonary nodule size and associated risks in chronic bronchitis patients.
• The therapeutic benefit of OM-85 is linked to an increased proportion of NK cells.
• OM-85 represents a promising therapeutic agent for managing high-risk pulmonary nodules in this patient population.