Post-exposure prophylaxis with SA58 (anti-SARS-COV-2 monoclonal antibody) nasal spray for the prevention of symptomatic COVID-19 in healthy adult workers: a randomized, single-blind, placebo-controlled clinical study*

ABSTRACT

Monoclonal antibodies (mAbs) and the post-exposure prophylaxis (PEP) with mAbs represent a very important public health strategy against coronavirus disease 2019 (COVID-19). This study has assessed a new Anti-SARS-COV-2 mAb (SA58) Nasal Spray for PEP against COVID-19 in healthy 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 the study period. A total of 1222 participants were randomized and dosed (SA58, n = 901; placebo, n = 321). Median of follow-up was 2.25 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. 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 reverse transcriptase polymerase chain reaction (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 and all were the Omicron variant BF.7. In conclusion, SA58 Nasal Spray showed favourable efficacy and safety in preventing symptomatic COVID-19 or SARS-CoV-2 infection in adults who had exposure to SARS-CoV-2 within 72 h.

KEYWORDS:

• Monoclonal antibodies
• Post-exposure prophylaxis
• SARS-CoV-2
• COVID-19
• Clinical trial
• China

Acknowledgements

We wish to thank all the participants who took part and contributed specimens in our study. RS, GZ, XM, WY, and RJ designed the trial and study protocol. RS and GZ contributed to the literature search. XX, XL, ZZ, and YC verified the data. JY and XM wrote the first draft manuscript. RS, GZ, XM, XX, YC, WY, and RJ contributed to the data interpretation and revision of the manuscript. XC, ZZ, and RJ contributed to data analysis. MX monitored the trial. XM, XC, JL, and ZZ were responsible for the site work including the recruitment, follow-up, and data collection, and XL was the site coordinator. XC and ZZ were responsible for the laboratory analysis. All the authors had full access to all the data in the study and had final responsibility for the decision to submit for publication.

Disclosure statement

XX and YC are the inventors of the provisional patent applications for the anti-SARS-CoV-2 monoclonal antibody (SA58). XX and YC are founders of Singlomics Biopharmaceuticals. SA58 have been transferred to Sinovac Biotech for clinical development. GZ, JY, XM, and WY are employees of Sinovac Biotech. JL and XL are employees of Sinovac Life Sciences. All other authors declare no competing interests.

Data sharing

De-identified individual participant-level data will be available upon written request to the corresponding author following publication.