AstraZeneca has recently announced that data from the AZD7442 COVID-19 PROVENT and TACKLE outpatient treatment phase III trials both showed robust efficacy from a one-time intramuscular dose of the long-acting antibody combination.

In an analysis of the ongoing PROVENT trial evaluating a median six months of participant follow-up, one 300mg IM dose of AZD7442, which is a combination of two LAABs (tixagevimab (AZD8895) and cilgavimab (AZD1061) derived from B-cells donated by convalescent patients after SARS-CoV-2 virus, reduced the risk of developing symptomatic COVID-19 compared to placebo by 83 per cent, the company said.

About 2 per cent of the global population is considered at increased risk of an inadequate response to a COVID-19 vaccine. This includes people with blood cancers or other cancers being treated with chemotherapy, patients on dialysis, those taking medications after an organ transplant or those who are taking immunosuppressive drugs for conditions including multiple sclerosis and rheumatoid arthritis.

The AZD7442 PROVENT trial is the first phase III trial prospectively designed to evaluate a monoclonal antibody for pre-exposure prophylaxis of symptomatic COVID-19, with targeted inclusion of high-risk and immunocompromised participants. More than 75 per cent of PROVENT participants at baseline had co-morbidities that put them at high risk for severe COVID-19 if they were to become infected, including people who are immunocompromised and may have a reduced immune response to vaccination.

There were no cases of severe COVID-19 or COVID-19-related deaths in those treated with AZD7442 at either the primary or six-month analyses. In the placebo arm, there were two additional cases of severe COVID-19 at the six-month assessment, for a total of five cases of severe COVID-19 and two COVID-related deaths.

An exploratory analysis of the TACKLE outpatient treatment trial, in patients with mild-to-moderate COVID-19, showed that one 600mg IM dose of AZD7442 reduced the risk of developing severe COVID-19 or death (from any cause) by 88 per cent compared to placebo in patients who had been symptomatic for three days or less at the time of treatment.

A total of 90 per cent of participants enrolled in TACKLE were from populations at high risk of progression to severe COVID-19 if they became infected, including those with co-morbidities.

Hugh Montgomery, Professor of Intensive Care Medicine at University College London, UK and AZD7442 principal investigator, said: “These compelling results give me confidence that this long-acting antibody combination can provide my vulnerable patients with the long-lasting protection they urgently need to finally return to their everyday lives. Importantly, six months of protection was maintained despite the surge of the Delta variant among these high-risk participants who may not respond adequately to vaccination.”

Full results from PROVENT and TACKLE will be submitted for publication in a peer-reviewed medical journal and presented at a forthcoming medical meeting. VNS