AstraZeneca Highlights Improved COVID-19 Antibody Protection in Immunocompromised

AstraZeneca announced on Thursday that its long-acting antibody, sipavibart, significantly lowered the incidence of symptomatic COVID-19 in a Phase III trial. This trial, known as SUPERNOVA, targeted immunocompromised individuals, who represent nearly a quarter of the cases with severe outcomes. In the trial, sipavibart was compared against a placebo and AstraZeneca’s older antibody cocktail, Evusheld (tixagevimab/cilgavimab).

The promising results position AstraZeneca to compete with Invivyd’s Pemgarda (pemivibart), which recently received emergency-use authorization in the United States for pre-exposure COVID-19 prophylaxis in immunocompromised patients. According to Iskra Reic, Executive Vice President of Vaccines and Immune Therapies at AstraZeneca, immunocompromised patients often have few or no options for COVID-19 protection, even when fully vaccinated. Reic emphasized that sipavibart has the potential to safeguard this vulnerable group.

In the SUPERNOVA trial, 3335 participants aged 12 and older, who were at risk of not responding adequately to vaccination and at high risk for severe COVID-19, were randomized to receive either a single 300mg intramuscular dose of sipavibart or a comparator (placebo or Evusheld). The trial's top-line results indicated that sipavibart achieved its dual primary endpoints: it reduced the risk of symptomatic COVID-19 from any SARS-CoV-2 variant and also lowered the risk of infections from variants that do not carry the F456L mutation, compared to the comparator. AstraZeneca highlighted that sipavibart provided consistent protection across different SARS-CoV-2 variants throughout the study.

Regarding safety, sipavibart was well tolerated, with a similar adverse-event profile to that of the placebo and Evusheld groups. Detailed results are expected to be presented at an upcoming medical conference.

AstraZeneca’s earlier antibody, Evusheld, lost its emergency-use authorization in the U.S. for pre-exposure prophylaxis early last year due to its inability to neutralize circulating SARS-CoV-2 variants in laboratory settings. With the new positive findings from the SUPERNOVA trial, AstraZeneca plans to engage with regulators to discuss the approval pathway for sipavibart, aiming to reestablish its foothold in the COVID-19 prophylactics market.