OM-85 and Respiratory Symptoms in Korean Chronic Obstructive Pulmonary Disease: A Multicenter Observational Study

Background: Although OM-85 may lessen respiratory symptoms and reduce acute exacerbations in chronic obstructive pulmonary disease (COPD), proof of its overall effectiveness remains incomplete. Methods: This prospective, observational, single-arm study was conducted at four university hospitals in South Korea from June 2022 to December 2023. Adults with spirometry-confirmed COPD who were prescribed OM-85 were enrolled, and followed for 6 months (3-months treatment, 3-months observation). Symptoms and health-related quality of life were assessed using the modified Medical Research Council scale, COPD Assessment Test (CAT), and St. George’s Respiratory Questionnaire (SGRQ). Acute exacerbations and adverse events were recorded. Results: Of the 323 patients analyzed (mean age 73.3±7.8 years; 83.9% male), 39.0% had baseline CAT ≥10. Patients in this group experienced markedly greater and sustained improvements in both CAT and SGRQ scores compared with those with CAT <10 (p for interaction <0.001 for both), and the magnitude of these changes exceeded the minimal clinically important difference (CAT: −3.21±3.85; SGRQ: −10.42±14.87 at 6 months), indicating clinically meaningful symptom relief. Among these patients, achieving SGRQ responder status at 6 months was negatively associated with an increased frequency of acute exacerbations (odds ratio, 0.246; 95% confidence interval, 0.050 to 1.207; p=0.084), showing a nonsignificant trend. OM-85 was well tolerated, with only mild, reversible drugrelated adverse events. Conclusion: OM-85 treatment resulted in meaningful improvements in symptoms and healthrelated quality of life, particularly among patients with more severe baseline symptoms, and was in general well tolerated.