AstraZeneca has reported positive data from the Phase III PROVENT clinical trial of its antibody combination, AZD7442, for the prevention of Covid-19.
High-level results showed that AZD7442 led to a statistically significant decrease in the occurrence of symptomatic illness.
AZD7442 consists of two long-acting antibodies (LAABs), tixagevimab (AZD8895) and cilgavimab (AZD1061), obtained from B-cells given by convalescent Covid-19 patients.
The randomised, double-blind, placebo-controlled, multi-centre PROVENT trial aims to assess pre-exposure prophylaxis and has enrolled a total of 5,197 subjects at 87 centres in the US, UK, Spain, France and Belgium.
The trial is evaluating the safety and efficacy of a single 300mg dose of AZD7442 compared with saline placebo, given intramuscularly in two distinct sequential injections, to prevent Covid-19.
The first case of symptomatic Covid-19, found positive with any SARS-CoV-2 RT-PCR, after dosing and before day 183 is the trial’s primary efficacy goal.
Participants will be followed up for 15 months.
AZD7442 reduced the risk of symptomatic illness development by 77% versus placebo.
At the trial’s primary analysis of 5,172 subjects who had no Covid-19 at baseline, 25 symptomatic cases were noted.
Among participants on AZD7442, no severe Covid-19 cases or related deaths were reported. Meanwhile, three severe Covid-19 cases, including two deaths, were seen in the placebo group.
The drug was well tolerated, with preliminary analyses demonstrating balanced adverse events between the treatment and placebo arms.
AZD7442 is the first antibody combination and non-vaccine product altered for potentially long-lasting protection that has shown Covid-19 prevention in a clinical trial, AstraZeneca noted.
AstraZeneca BioPharmaceuticals R&D executive vice-president Mene Pangalos said: “We are very encouraged by these efficacy and safety data in high-risk people, showing our long-acting antibody combination has the potential to protect from symptomatic and severe disease, alongside vaccines.
“We look forward to sharing further data from the AZD7442 Phase III clinical trial programme later this year.”
The LAABs that comprise AZD7442 were discovered by Vanderbilt University Medical Center and licensed to AstraZeneca in June 2020.
AstraZeneca optimised the antibodies using its YTE half-life extension technology, which could enable up to 12 months of protection against Covid-19.
In vitro studies at the University of Oxford and Columbia University found that AZD7442 neutralises recent emergent variants of SARS-CoV-2, including Delta.
The company plans to submit prophylaxis results from PROVENT and STORM CHASER trials to regulatory authorities for emergency use authorisation or conditional approval of AZD7442.