Polyclonal Antibody Therapy Looks Promising in COVID-19 Trial

Topline results were announced from a phase 3 study evaluating SAB-185, a human IgG1 (polyclonal) antibody therapeutic candidate, for the treatment of nonhospitalized patients with COVID-19 at high risk for severe outcomes.

The National Institutes of Health (NIH) ACTIV-2 clinical trial (ClinicalTrials.gov Identifier: NCT04518410) was initiated to evaluate the safety and efficacy of different therapies to reduce the duration of symptoms of COVID-19 in adult outpatients.

An analysis of data showed that 66% of patients treated with SAB-185 reached full symptom resolution for at least 4 days by day 28 compared with 50% of those who received the monoclonal antibody combination REGEN-COV^® (casirivimab and imdevimab) (P =.01).

Median time to symptom resolution for at least 2 consecutive days was observed to be shorter with SAB-185 vs REGEN-COV:

• Non-Omicron population: 15 days vs 19 days (not statistically significant);
• Omicron population: 17 days vs 23 days (P =.021).

Similarly, symptom resolution for at least 4 consecutive days occurred sooner with SAB-185 vs REGEN-COV:

• Non-Omicron population: 16 days vs 23 days (not statistically significant);
• Omicron population: 18 days vs 25 days (P =.01).

The primary endpoint of the study, a composite of all-cause hospitalizations and deaths, was found to be inconclusive due to the small number of clinical events. Treatment-emergent adverse events (grade 3 or higher) were reported to be similar between groups.