A human clinical trial evaluating the monoclonal antibody Dengue-mAb, also known as VIS513, demonstrated a rapid reduction in infectious dengue virus levels in adult patients, according to findings published in JAMA Network Open by P.S. Kulkarni and colleagues. The trial offers the first preliminary clinical evidence of a direct-acting treatment for the circulating dengue virus, moving a therapeutic candidate from preclinical testing into measurable patient impact.
Clinical Trial Design and Patient Demographics
The randomized clinical trial enrolled 250 adult patients aged 18 to 60 years within 48 hours of fever onset across 12 hospitals in India, according to the published study data. Participants received a single two-hour intravenous infusion of the monoclonal antibody at doses of 3, 5, 7, or 9 milligrams per kilogram of body weight, or a placebo. Unlike vaccines that prime the immune system before exposure, Dengue-mAb is designed to intervene after infection has begun by binding to a conserved region on the viral surface protein shared across all four known serotypes, aiming to prevent the virus from infecting new cells.
Viremia Reduction and Symptom Timeline
According to the study results, infectious virus levels dropped more rapidly in all treatment groups within 24 hours of administration. Among participants with measurable viremia at baseline, blood samples from individuals who received doses between 5 and 9 milligrams per kilogram became negative for the virus within 8 hours. By comparison, the placebo group required up to 72 hours to achieve the same result. Researchers also observed a faster reduction in fever duration among patients receiving the intermediate doses, with the median time to sustained fever resolution dropping to 3.5 and 2 hours, respectively, compared with 26.8 hours in the placebo group.
Study Limitations and Next Steps
Study authors noted that the findings remain preliminary due to the small subset of participants with detectable viremia and active fever at enrollment. Only 32 participants had a measurable viral load at baseline, and 71 presented with fever, resulting in small comparison groups for secondary endpoints. Furthermore, none of the trial participants developed severe dengue, meaning the study could not evaluate whether the treatment prevents hospitalization, hemorrhage, or death. The trial was sponsored by the Serum Institute of India, which manufactures the treatment. A Phase 3 trial is currently underway in India, and an expanded study involving approximately 1,000 participants is planned in Brazil, Malaysia, and Thailand to determine clinical efficacy against severe disease outcomes.
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