Efficacy and safety of sipavibart for prevention of COVID-19 in individuals who are immunocompromised (SUPERNOVA): a randomised, controlled, double-blind, phase 3 trial.

Background: Sipavibart is an anti-spike monoclonal antibody that neutralises SARS-CoV-2 with exceptions, including Phe456Leu-containing variants (eg, KP.2* and KP.3*). This trial assessed sipavibart efficacy and safety for prevention of symptomatic COVID-19 in participants who are immunocompromised.

Methods: In this ongoing, double-blind, international, phase 3 trial, we enrolled participants who were immunocompromised and aged 12 years or older at 197 hospitals, university health centres, and clinical trial units in 18 countries. Participants were randomly allocated 1:1 to a sipavibart group (intramuscular sipavibart 300 mg on days 1 and 181) or a comparator group (tixagevimab 300 mg-cilgavimab 300 mg on day 1 and placebo on day 181 or placebo on days 1 and 181), stratified by previous COVID-19 vaccination and infection status and use of tixagevimab-cilgavimab. The primary efficacy outcomes were symptomatic COVID-19 caused by any variant or symptomatic COVID-19 caused by non-Phe456Leu-containing variants within 181 days of dosing, assessed in the SARS-CoV-2-negative set, comprising all participants without a positive RT-PCR test for SARS-CoV-2 at baseline and who received at least one trial intervention dose. Safety outcomes for adverse events were assessed 90 days following the first dose and for serious adverse events throughout the study in the safety analysis set (ie, all participants who received at least one injection of sipavibart or comparator). This study is registered with ClinicalTrials.gov, NCT05648110.