medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 1 Effect of human umbilical cord-derived mesenchymal stem cells on lung 2 damage in severe COVID-19 patients: a randomised, double-blind, 3 placebo controlled phase 2 trial 4 Lei Shi1,2*, Hai Huang3,4*, Xuechun Lu2,5*, Xiaoyan Yan6*, Xiaojing Jiang7, Ruonan Xu1, 5 Siyu Wang1, Chao Zhang1,2, Xin Yuan1,2, Zhe Xu1,2, Lei Huang1,2, Jun-Liang Fu1,2, 6 Yuanyuan Li1, Yu Zhang8,9, Weiqi Yao9,10, Tianyi Liu2,11, Jinwen Song1,2, Liangliang 7 Sun4,12, Fan Yang13, Xin Zhang2,14, Bo Zhang7, Ming Shi1, Fanping Meng1, Yanning Song1, 8 Yongpei Yu6, Jiqiu Wen2, Qi Li2, Qing Mao2, Markus Maeurer16,17, Alimuddin Zumla18, 9 Chen Yao6#, Wei-Fen Xie4,15#, Fu-Sheng Wang1,2# 10 11 1. Department of Infectious Diseases, Fifth Medical Center of Chinese PLA General 12 Hospital, National Clinical Research Center for Infectious Diseases, Beijing, China. 13 2. Wuhan Huoshenshan Hospital, Wuhan, China. 14 3. Department of Respiratory, Changzheng Hospital, Second Military Medical University, 15 Shanghai, China. 16 4. Optical Valley Branch of Maternal and Child Hospital of Hubei Province, Wuhan, 17 China. 18 5. Department of Hematology, Second Medical Center of Chinese PLA General Hospital, 19 Beijing, China. 20 6. Peking University Clinical Research Institute, Peking University First Hospital, Beijing, 21 China. 22 7. Department of Infectious Disease, General Hospital of Central Theater Command, 23 Wuhan, China. Page 1 of 28 NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice. medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 24 8. VCANBIO Cell & Gene Engineering Corp., Ltd. Tianjin, China. 25 9. National Industrial Base for Stem Cell Engineering Products, Tianjin, China. 26 10. Department of Hematology, Union Hospital, Tongji Medical College, Huazhong 27 University of Science and Technology, Wuhan, China. 28 11. Key Laboratory of Cancer Center, Fifth Medical Center of Chinese PLA General 29 Hospital, Beijing, China. 30 12. Department of Endocrinology and Metabolism, Changzheng Hospital, Second Military 31 Medical University, Shanghai, China. 32 13. Department of Radiology, Union Hospital, Tongji Medical College, Huazhong 33 University of Science and Technology, Wuhan, China. 34 14. Nursing Department, Fifth Medical Center of Chinese PLA General Hospital, Beijing, 35 China. 36 15. Department of Gastroenterology, Changzheng Hospital, Second Military Medical 37 University, Shanghai, China. 38 16. Immunotherapy Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal. 39 17. I Med Clinic, University of Mainz, Mainz, Germany. 40 18. Center for Clinical Microbiology, Division of Infection and Immunity, University 41 College London, and UCL Hospitals NIHR Biomedical Research Centre, London, UK 42 * Drs. Lei Shi, Hai Huang, Xuechun Lu and Xiaoyan Yan contributed equally to this 43 article. 44 Correspondence to: 45 # Prof. Fu-Sheng Wang, Department of Infectious Diseases, Fifth Medical Center of 46 Chinese PLA General Hospital, National Clinical Research Center for Infectious Diseases, Page 2 of 28 medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 47 No.100 Western 4th Ring Road, Beijing 100039, China. [email protected] 48 # Prof. Wei-Fen Xie, Department of Gastroenterology, Changzheng Hospital, Second 49 Military Medical University, 415 Fengyang Road, Shanghai, 200003, China. 50 [email protected] 51 # Prof. Chen Yao, Peking University Clinical Research Institute, Peking University First 52 Hospital, No. 8 Xishiku Street, Xicheng District, Beijing 100034, China 53 [email protected] Page 3 of 28 medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 54 Abstract 55 Objective 56 To assess the safety and efficacy of human umbilical cord-derived MSCs (UC-MSCs) for 57 severe COVID-19 patients with lung damage. 58 Design, 59 Multicentre, randomised, double-blind, placebo-controlled trial. 60 Setting 61 Two hospitals in Wuhan, China, 5 March 2020 to 28 March 2020. 62 Participants 63 101 severe COVID-19 patients with lung damage aged between 18–74 years. 64 Intervention 65 Patients were randomly assigned at a 2:1 ratio to receive either UC-MSCs (4 × 107 cells 66 per infusion) or placebo on days 0, 3, and 6. 67 Main outcome measures 68 The primary endpoints were safety and an altered proportion of whole lung lesion size 69 from baseline to day 28, measured by chest computed tomography. Secondary outcomes 70 were reduction of consolidation lesion sizeand lung function improvement (6-minute walk 71 test, maximum vital capacity, diffusing capacity). Primary analysis was done in the 72 modified intention-to-treat (mITT) population and safety analysis was done in all patients 73 who started their assigned treatment. 74 Results 75 100 patients were finally recruited to receive either UC-MSCs (n = 65) or placebo (n = 35). 76 The patients receiving UC-MSCs exhibited a trend of numerical improvement in whole 77 lung lesion size from baseline to day 28 compared with the placebo cases (the median 78 difference was -13.31%, 95%CI -29.14%, 2.13%, P=0.080). UC-MSCs administration Page 4 of 28 medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 79 significantly reduced the proportions of consolidation lesion size from baseline to day 28 80 compared with the placebo (median difference: -15.45%, 95% CI -30.82%, -0.39%, 81 P=0.043). The 6-minute walk test showed an increased distance in patients treated with 82 UC-MSCs (difference: 27.00 m, 95% CI 0.00, 57.00, P=0.057). The incidence of adverse 83 events was similar, and no serious adverse events were observed in the two groups. 84 Conclusions 85 UC-MSCs treatment is a safe and potentially effective therapeutic approach for COVID-19 86 patients with lung damage. A phase 3 trial is required to evaluate effects on reducing 87 mortality and preventing long-term pulmonary disability. 88 Trial registration 89 ClinicalTrials.gov Identifier: NCT04288102 Page 5 of 28 medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 90 Key Points 91 Question 92 Are human umbilical cord-derived mesenchymal stem cells (UC-MSCs) safe and effective 93 therapeutic option for limiting lung damage in severe coronavirus disease 2019 94 (COVID-19)? 95 Finding 96 In this randomised, double-blind, placebo-controlled, phase 2 trial that included 100 97 COVID-19 patients with lung damage, human UC-MSCs medication showed a trend of 98 improvement in whole lung lesion size and significantly reduced the proportions of 99 consolidation lesions from baseline to day 28 in the treated patients compared with the 100 placebo subjects. The 6-minute walk test showed a longer distance in UC-MSCs than 101 placebo group but without significantly difference. UC-MSCs delivery was well tolerated, 102 with no serious adverse events. 103 Meaning 104 Human UC-MSC administration for hospitalized COVID-19 with lung damage is safe. 105 Treatment with human UC-MSC improves the resolution of lung lesions, particularly the 106 consolidation lesions. 107 108 Page 6 of 28 medRxiv preprint doi: https://doi.org/10.1101/2020.10.15.20213553; this version posted October 20, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-ND 4.0 International license . 109 Introduction 110 The Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome 111 coronavirus 2 (SARS-CoV-2) infection,1 causes substantial damage to lungs, ranging from 112 mild respiratory illness to severe acute respiratory syndrome, and death,2-4 Dysregulated 113 immune responses of both the innate and adaptive immune systems are associated with 114 disease severity, lung damage and long term functional disability.5-8 There are currently no 115 prophylactic vaccines or effective antiviral agents available to treat COVID-19 and 116 management of COVID-19 patients remains largely symptomatic and supportive therapy.9 117 Therefore, there is an urgent need for safe and alternative therapeutic options to mitigate 118 inflammatory organ injury.