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HMBD-115 (also known as SC31) is a potent SARS-CoV-2 neutralizing antibody for the treatment of COVID-19, developed in collaboration with partners in Singapore and the US.

Pre-clinical data has demonstrated significant therapeutic benefit for HMBD-115 in multiple models of COVID-19. After treatment, circulating infectious virus was dramatically lowered and the inflammatory immune responses associated with life-threatening systemic disease were greatly reduced, which together prevented lung damage and significantly improved survival. Hummingbird, and its partners, received clinical trial authorization in October 2020 and the Phase I/II clinical trial of HMBD-115 is ongoing with early read-out expected in December 2020. A Phase III trial is scheduled for the end of 2020.

SARS-CoV-2 neutralizing antibodies are promising therapeutics for COVID-19 and offer an important treatment option in the absence of an effective vaccine, and for at-risk patients who may respond poorly to a vaccine.  Emerging data from other antibody programs has been encouraging, however, there remains much to understand about the optimal mechanisms of action and effective treatment strategies. Occurrence of Antibody Dependent Enhancement (ADE) of viral infection, for instance, continues to be a major concern in therapeutics development where sub-optimal antibodies can aid the entry of virus into host cells. This phenomenon has been observed to be a driver of immune dysregulation in severe disease and remains a challenge to be overcome.

HMBD-115 binds tightly to a highly conserved viral epitope on the spike protein of all circulating strains of the SARS-CoV-2 virus, and potently blocks viral infection of host cells. Unlike some other therapeutic antibodies in development, HMBD-115 also engages with human Fcγ receptors on immune cells to promote natural anti-viral responses without triggering the pro-inflammatory pathways linked to cytokine storms and severe disease. Further, HMBD-115 has shown no evidence of ADE.


Chan, C. E. Z., Seah, S. G. K., De Hoe Chye, Massey, S., Torres, M., Angeline P.C. Lim, et al. (2020). The Fc-mediated effector functions of a potent SARS-CoV-2 neutralizing antibody, SC31, isolated from an early convalescent COVID-19 patient, are essential for the optimal therapeutic efficacy of the antibody. bioRxiv, 2020.10.26.355107. http://doi.org/10.1101/2020.10.26.355107

 HMBD-115 blocks SARS-CoV-2 spike protein from binding hACE2 protein and infecting host cells

SARS-CoV-2 Spike Protein

Receptor Binding Domains

HMBD-115 has been engineered for drug stability and developability. Robust manufacturing and testing processes have been established that allow HMBD-115 to be produced at large scale, with a GMP-validated high-expression Master Cell Bank producing over 4 g/L.


Lv, Z., et al (2020) Science 369: 1505-1509

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27 October 2020

Hummingbird Bioscience receives clinical trial authorization to initiate a Phase I/II clinical trial for HMBD-115, an anti-SARS-CoV-2 antibody for the treatment of COVID-19. A pre-print paper is published on bioRxiv.