Which immunotherapies are being investigated for the treatment of coronavirus disease 2019 (COVID-19)?

Updated: Jun 25, 2021
  • Author: David J Cennimo, MD, FAAP, FACP, FIDSA, AAHIVS; Chief Editor: Michael Stuart Bronze, MD  more...
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Bucillamine (Revive Therapeutics) is an antirheumatic agent derived from tiopronin. It has been available in Japan and South Korea for over 30 years. N-acetyl-cysteine (NAC) has been shown to significantly attenuate clinical symptoms in respiratory viral infections in animals and humans, primarily via donation of thiols to increase antioxidant activity of cellular glutathione. Bucillamine has 2 thiol groups and its ability as a thiol donor is estimated to be 16 times that of NAC. A phase 3 confirmatory trial for treatment of outpatients with mild-to-moderate COVID-19 at 10 sites in the US planned for Q1 2021 with enrollment goal of 1000 participants. [284]  


MK-7110 (formerly CD24Fc; Merck) is a biological immunomodulator in Phase II/III clinical trial stage. It is a fusion protein comprised of the nonpolymorphic regions of CD24 attached to the Fc region of human IgG1. An interim analysis in September 2020 of data from the Phase 3 trial (SAC-COVID) in 243 participants (full enrollment) indicated that hospitalized patients with COVID-19 treated with a single dose of MK-7110 showed a 60% higher probability of improvement in clinical status compared to placebo, as defined by the protocol. The risk of death or respiratory failure was reduced by more than 50%. [285]  

Other immunotherapies are in early clinical trials. 

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