SA58 for COVID-19

ABSTRACTBACKGROUNDThis study has assessed a new Anti-COVID-19 Monoclonal Antibody Nasal Spray (SA58) for post-exposure prophylaxis (PEP) against symptomatic coronavirus disease 2019 (COVID-19).METHODSWe conducted an efficacy study in adults aged 18 years and older within three days of exposure to a SARS-CoV-2 infected individual. Recruited participants were randomized in a ratio of 3:1 to receive SA58 or placebo. Primary endpoints were laboratory-confirmed symptomatic COVID-19 within study period.FINDINGSA total of 1,222 participants were randomized and dosed (SA58, n=901; placebo, n=321). Median of follow-up was 2·25 days and 2·79 days for SA58 and placebo, respectively. Adverse events occurred in 221 of 901 (25%) and 72 of 321 (22%) participants with SA58 and placebo, respectively, with no significant difference (P=0·49). All adverse events were mild in severity. Laboratory-confirmed symptomatic COVID-19 developed in 7 of 824 participants (0·22 per 100 person-days) in the SA58 group vs 14 of 299 (1·17 per 100 person-days) in the placebo group, resulting in an estimated efficacy of 80 · 82% (95%CI 52 · 41%-92 · 27%). There were 32 SARS-CoV-2 RT-PCR positives (1·04 per 100 person-days) in the SA58 group vs 32 (2·80 per 100 person-days) in the placebo group, resulting in an estimated efficacy of 61·83% (95%CI 37·50%-76·69%). A total of 21 RT-PCR positive samples were sequenced. 21 lineages of SARS-CoV-2 variants were identified, and all were the Omicron variant BF·7.INTERPRETATIONSA58 Nasal Spray showed favorable efficacy and safety in preventing SARS-CoV-2 infection or symptomatic COVID-19 in healthy adult workers who had exposure to SARS-CoV-2 within 72 hours.FUNDINGNo funding was received for this study.Research in contextEvidence before this studyMonoclonal antibodies (mAbs) and the post-exposure prophylaxis (PEP) with mAbs represent a very important public health strategy against COVID-19 outbreak. SA58 Nasal Spray is a broad-spectrum anti-COVID-19 mAb, developed by Sinovac Life Sciences Ltd. for treatment and prophylaxis against COVID-19. SA58 has been shown to potently neutralize ACE2-utilizing sarbecoviruses, including most of circulating Omicron variants. We searched PubMed on Nov 21, 2022, for published clinical trials, with no language or date restrictions, using various combinations of the search terms of “monoclonal antibodies”, “SARS-CoV-2”, “COVID-19”, “prophylaxis”, and “prevention”. Three published trials were identified. The first study reported the efficacy of AZD7442 (tixagevimab/cilgavimab) PEP against symptomatic COVID-19 in adults aged ≥18 years over a 183-day follow-up period. The primary efficacy end point of post-exposure prevention of symptomatic COVID-19 was not met, though AZD7442 showed promising results in participants who were SARS-CoV-2 RT-PCR negative at baseline. The second study reported the efficacy and safety of bamlanivimab for COVID-19 prevention in household contacts of individuals with a SARS-CoV-2..