Experimental monoclonal antibody combo shows significant efficacy against COVID-19

As part of the NIH-sponsored ACTIV-2 clinical trial for COVID-19 outpatients, preliminary data revealed that a new combination monoclonal antibody treatment reduced hospitalizations and death by 78 percent in high-risk patients. ACTIV-2 vice chair David Wohl, MD, leads monoclonal treatment for UNC Health.

Brii Biosciences based in Durham, N.C., released interim data from a phase 2/3 ACTIV-2 study of a monoclonal antibody combination therapy BRII-196/BRII-198, which reduced COVID-19 hospitalizations and death by 78 percent in high-risk patients compared with placebo.

The study, sponsored by the National Institute of Allergy and Infectious Diseases, evaluated 837 patients enrolled within 10 days of COVID-19 symptom onset and at high risk for clinical progression and followed them for 28 days following treatment. Twelve patients in the therapy group became hospitalized, compared to 45 in the placebo group. One patient in the therapy group died, compared to nine in the placebo group. Patients in the therapy group also experienced fewer grade-three or higher adverse events (3.8 percent vs. 13.4 percent in placebo group), with few events in the therapy group categorized as drug-related.

These data are preliminary and have not been published or peer-reviewed. Once the ACTIV-2 study is completed, the full analysis will include participants from the United States, Brazil, South Africa, Mexico, Argentina and the Philippines between January and July 2021. According to Brii Biosciences, data on the efficacy of the combination therapy by variant type will be evaluated, as well.

"So far, this therapy and other monoclonal antibodies show effectiveness against the Delta variant, which now accounts for almost all the COVID-19 cases in the U.S.," said David Wohl, MD, professor of infectious disease at the UNC School of Medicine and vice chair of the ACTIV-2 study. "We continue to need effective ways to treat patients to help them avoid severe illness and death. Monoclonals are one tool we have. That said, according to everything we've learned since the beginning of the pandemic, the best tools we have to prevent hospitalization and death are vaccines and masking in public indoor places."

Other potential therapies are also being studied in the ACTIV-2 trial, including medications that are inhaled, taken orally, or as a single injection.

For more information on ACTIV-2 and NIH COVID-19 treatment trials, visit riseabovecovid.org and combatcovid.hhs.gov.

Read more about BRII-196/BRII-198 results at the Brii Biosciences website.