SAB Biotherapeutics (NASDAQ:SABS) reported positive top-line results from the Phase 3 National Institutes of Health’s ACTIV-2 clinical trial that assessed SAB-185 in non-hospitalized people with COVID-19 who were at high risk for severe outcomes.
Trial data show that SAB-185 demonstrated benefit in sustained symptom resolution in study participants with COVID-19 caused by Omicron, compared with participants who received a monoclonal antibody combination, REGEN-COV (casirivimab and imdevimab).
Specifically, 66% of participants treated with SAB-185 reached full symptom resolution for at least four consecutive days by day 28, while only 50% of participants on REGEN-COV met this endpoint, and the median time to symptom resolution for at least four consecutive days was seven days shorter for SAB-185.
In addition, the median time to symptom resolution for at least two consecutive days was six days shorter for SAB-185, compared with those who were treated with REGEN-COV.
In the non-Omicron population, the median time to symptom resolution for at least four consecutive days was seven days shorter for SAB-185, and the median time to symptom resolution for at least two consecutive days was four days shorter for SAB-185 than REGEN-COV, though neither of these analyses met statistical significance.
The primary endpoint of the study was the composite of all-cause hospitalizations and deaths. Following the emergence of the Omicron variant in late 2021, the number of these clinical events dropped significantly.
An interim review conducted by the study’s Data and Safety Monitoring Board determined that there would not be enough clinical events in this study, with the number of participants specified in the protocol, to arrive at a conclusive result, and the trial was halted.
These data were analyzed and showed the primary endpoint was considered inconclusive for both non-inferiority or superiority in non-Omicron and Omicron patients due to the small number of hospitalizations and deaths. Grade 3 or higher treatment emergent adverse event rates were similar between SAB-185 and REGEN-COV arms.
“The ACTIV-2 data is further validation of the potential of SAB’s platform,” Eddie Sullivan, Ph.D., co-founder, president, and CEO of SAB, said in a statement. “It shows that the DiversitAb platform can open the door to treatments that are potentially more effective and potent and which remain efficacious over longer periods of time versus monoclonal antibodies.”
