Hyun W. Lee ¹ Jaegu Seo ² Sang-Nam Lee ² Yemo Koo ² Sung- Yoon Kang ³ Cheonwoong Choi ⁴ So-Young Park ⁵ Suh-Young Lee ^6,7 Sung-Ryeol Kim ⁸ Joo-Hee Kim ⁹ HYE SOOK CHOI ^10*

• ¹ Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, Republic of Korea
• ² Enterobiome Inc., Goyang-si, Gyeonggi, Republic of Korea
• ³ Gachon University Gil Medical Center, Incheon, Republic of Korea
• ⁴ Kyung Hee University Hospital at Gangdong, Kyung Hee University, Dongdaemun, Seoul, Republic of Korea
• ⁵ Chung-Ang University Gwangmyeong Hospital, Gwangmyeonsi, Gyeonggi, Republic of Korea
• ⁶ Seoul National University Hospital, Seoul, Republic of Korea
• ⁷ Medical Research Center, Seoul National University, Seoul, Seoul, Republic of Korea
• ⁸ Yongin Severance Hospital, College of Medicine, Yonsei University, Seoul, Seoul, Republic of Korea
• ⁹ Hallym University Sacred Heart Hospital, Anyang-si, Gyeonggi, Republic of Korea
• ¹⁰ Department of Internal Medicine, College of Medicine, Kyung Hee University, Seoul, Seoul, Republic of Korea

Introduction: Respiratory symptoms are prevalent in the general population, and they are associated with a decline in lung function and increased mortality. The gut-lung connection suggests intestinal dysbiosis may impact lung diseases, with Akkermansia muciniphila showing promise in regulating extraintestinal diseases. However, its application in patients with respiratory symptoms lacks clinical trial evidence.In this randomized, double-blind trial, ETB-F01, containing heat-killed Akkermansia muciniphila strain EB-AMDK19, was compared with a placebo in patients experiencing respiratory symptoms for 4 to 12 weeks. Primary outcome was the improvement in Breathlessness, Cough, and Sputum Scale (BCSS) scores over 12 weeks. Secondary outcomes included lung function, fractional exhaled nitric oxide (FeNO), modified Medical Research Council (mMRC) dyspnea scale, St. George's Respiratory Questionnaire (SGRQ), and Visual Analog Scale (VAS) score and safety assessments. The primary analysis was performed in the per-protocol set, with a sensitivity analysis in the full analysis set.Results: In the per-protocol population, 68 participants were randomly assigned to the ETB-F01 group and 65 to the placebo group. ETB-F01 had a superior efficacy over placebo in improving BCSS total scores (between-group difference=-0.8 (95% confidence interval, -1.4--0.3), P-value=0.004). Specifically, there was a significant reduction in BCSS breathlessness and cough domain scores with ETB-F01. While trends toward improvement in lung function were noted, statistical significance was not achieved. No significant differences were observed in FeNO and other symptom scores (mMRC, SGRQ, and VAS). In safety profile, ETB-F01 did not significantly increase adverse events with no serious adverse events.ETB-F01 showed therapeutic potential in alleviating respiratory symptoms, highlighting the microbiota-mediated approach's promise in respiratory medicine. Further exploration is warranted to understand the underlying mechanisms and enhance the generalizability of findings.This trial was registered in Clinical Research Information Service of the Republic of Korea (KCT0008680). https://cris.nih.go.kr/cris/search/detailSearch.do?search_lang=E&focus=reset_12&search_pa ge=L&pageSize=10&page=undefined&seq=25684&status=5&seq_group=24694 Primary Source of Funding: Enterobiome Inc.