SAB-185 for COVID-19

ABSTRACT Background SAB-185, a novel fully-human IgG polyclonal immunoglobulin product, underwent phase 2 evaluation for non-hospitalized adults with mild-moderate COVID-19. Methods Participants received intravenous SAB-185 3,840 units/kg (low-dose) or placebo, or 10,240 units/kg (high-dose) or placebo. Primary outcome measures were nasopharyngeal SARS-CoV-2 RNA <lower limit of quantification (LLoQ) at study days 3, 7, and 14, time to symptomatic improvement, and safety through day 28. Results Two-hundred thirteen participants received low-dose SAB-185/placebo (n=107/106) and 215 high-dose SAB-185/placebo (n=110/105). The proportions with SARS-CoV-2 RNA <LLoQ were higher for SAB-185 versus placebo at days 3 and 7 and similar at day 14, and significantly higher at day 7 for high-dose SAB versus placebo only, relative risk (95% CI) 1.23 (1.01, 1.49). At day 3, SARS-CoV-2 RNA levels were lower with low-dose and high-dose SAB-185 versus placebo, differences in medians of -0.78 log10copies/mL (p=0.08) and -0.71 log10copies/mL (p=0.10), respectively. No difference was observed in time to symptom improvement: median 11/10 days (p=0.24) for low-dose SAB-185/placebo and 8/10 days (p=0.50) for high-dose SAB-185/placebo. Grade ≥3 adverse events occurred in 5%/13% of low-dose SAB-185/placebo and 9%/12% of high-dose SAB-185/placebo. Conclusions SAB-185 was safe and generally well tolerated and demonstrated modest antiviral activity in predominantly low-risk non-hospitalized adults with COVID-19.

Abstract Background To address the need for novel COVID-19 therapies, we evaluated the fully-human polyclonal antibody product SAB-185 in a phase 3 clinical trial. Methods Non-hospitalized high-risk adults within 7 days of COVID-19 symptom onset were randomized 1:1 to open-label SAB-185 3,840 units/kg or casirivimab/imdevimab 1200 mg. Non-inferiority comparison was undertaken for the pre-Omicron population (casirivimab/imdevimab expected to be fully active) and superiority comparison for the Omicron population (casirivimab/imdevimab not expected to be active). Primary outcomes were the composite of all-cause hospitalizations/deaths and grade ≥3 treatment-emergent adverse events (TEAEs) through day 28. Secondary outcomes included time to sustained symptom improvement and resolution. Results Enrollment was terminated early due to low hospitalization/death rates upon Omicron emergence. 733 adults were randomized, 255 included in pre-Omicron and 392 in Omicron analysis populations. Hospitalizations/deaths occurred in 6 (5.0%) and 3 (2.2%) of pre-Omicron SAB-185 and casirivimab/imdevimab arms, respectively (absolute difference [95% CI] 2.7% [-2.3%, 8.6%]), inconclusive for non-inferiority; and 5 (2.5%) versus 3 (1.5%) (absolute difference 1.0% [-2.3%, 4.5%]) for Omicron. Risk ratios for grade ≥3 TEAEs were 0.94 [0.52, 1.71] (pre-Omicron) and 1.71 [0.96, 3.07] (Omicron). Time to symptom improvement and resolution were shorter for SAB-185, median 11 vs 14 (pre-Omicron) and 11 vs 13 days (Omicron) (symptom improvement), and 16 vs 24 days and 18 vs >25 days (symptom resolution), p<0.05 for symptom resolution for Omicron only. Conclusions SAB-185 had an acceptable safety profile with faster symptom resolution in the Omicron population. Additional studies are needed to characterize its efficacy for COVID-19.

ABSTRACT Context To meet the need for effective treatments during the COVID‐19 Public Health Emergency, the U.S. government sought to accelerate the discovery and development of new antiviral treatments—a process that normally took 4–12 years. The government changed many features of the established system, selecting the investigational drugs, sponsoring or conducting the clinical testing, and purchasing and managing the distribution of the successful products. Methods We focused on novel therapeutic agents for COVID‐19 that were funded, clinically tested, and/or received Emergency Use Authorization during the Public Health Emergency from January 2020 to May 2023. The primary sources were the public records of the National Institutes of Health, the U.S. Food and Drug Administration, and the Biomedical Advanced Research and Development Authority. Excluded were vaccines, devices, diagnostic tests, and new indications for approved drugs. Results In less than 24 months, the emergency program developed, tested, approved, and distributed eight new therapeutic products, including six monoclonal antibodies and two new oral antivirals. In addition, 11 other investigational agents were funded or tested under the emergency program but did not receive Emergency Use Authorization. More than 30 million courses of treatment were distributed at a cost of $29 billion or $881 per patient. By the end of the emergency, viral mutations and rapidly growing population immunity rendered the new products ineffective in almost all patients. Conclusions The emergency program was dramatically effective in finding and testing new drug treatments using a variety of clinically relevant endpoints and serving varied patient populations. Planning for future pandemics should include a global network of clinical testing centers that were key to a rapid response. Research is needed to discover more durable antiviral treatments, especially in settings where mutation and population immunity are subject to rapid change.