PHASE-2 STUDY of SAB-185, A POLYCLONAL ANTIBODY TREATMENT for COVID-19 in ACTIV-2

ABSTRACT

Background: The discovery and development of SARS-CoV-2 therapies remains a priority. SAB-185 is a Transchromosomic, bovine-derived, fully human polyclonal immunoglobulin product for SARS-CoV-2 being studied in ACTIV-2, randomized controlled platform trial evaluating the safety and efficacy of investigational agents for non-hospitalized adults with mild-moderate COVID-19 Methods: This Phase II trial was a superiority comparison of SAB-185 vs. placebo. Participants with confirmed SAR-CoV-2 infection received intravenous infusion of SAB-185 (3,840 Units/kg) or placebo. Primary outcome measures were proportion of participants with SARS-CoV-2 RNA < lower limit of quantification (LLoQ) in nasopharyngeal (NP) swab, time to improvement in targeted symptoms for 2 consecutive days after Day 0, and safety through Day 28. Secondary outcomes included quantitative NP RNA levels and all-cause hospitalizations and deaths. Antiviral or clinical efficacy and safety criteria for graduation to Phase III were pre-specified. Results: From April to August 2021, randomized participants from 42 sites in the US received SAB-185 (N=107) or placebo (N=106). Median age was 38 years (quartiles 30,48), 54% female, >98% cis-gender, 7% Black/African-American, 50% Hispanic, and 11% were classified as high-risk for COVID-19 progression, with median 4 days (3,6) from symptom onset. Day 0 NP SARS-CoV-2 RNA levels were similar between SAB-185 and placebo 4.80 vs 4.80 log10 copies/ml. No differences were observed in the proportion with NP SARS-CoV-2 RNA< lower limit of quantification (LLoQ) in nasopharyngeal (NP) swab, time to improvement in targeted symptoms for 2 consecutive days after Day 0, and safety through Day 28. Secondary outcomes included quantitative NP RNA levels and all-cause hospitalizations and deaths. Antiviral or clinical efficacy and safety criteria for graduation to phase 3 were pre-specified. Conclusion: SAB-185 was safe in this Phase II study. While no significant differences to placebo were seen in symptom duration and proportion of participants with NP SARS-CoV-2 RNA< lower limit of quantification (LLoQ) in nasopharyngeal (NP) swab, time to improvement in targeted symptoms for 2 consecutive days after Day 0, and safety through Day 28. Secondary outcomes included quantitative NP RNA levels and all-cause hospitalizations and deaths. Antiviral or clinical efficacy and safety criteria for graduation to phase 3 were pre-specified.