AstraZeneca Says Antibody Combo Can Prevent COVID

— Top-line phase III data finds efficacy of therapy as COVID pre-exposure prophylaxis

MedicalToday
A computer rendering of monoclonal antibodies

A cocktail of long-acting antibodies administered intramuscularly as COVID-19 prevention cut the risk of developing symptomatic disease in a high-risk unvaccinated patient population, on Friday.

In top-line data from a phase III trial, AZD7442 (tixagevimab and cilgavimab) as pre-exposure prophylaxis significantly reduced the risk of developing COVID-19 symptoms by 77% (95% CI 46%-90%) versus placebo, meeting the trial's primary endpoint.

Moreover, AstraZeneca noted there were no cases of severe COVID-19 or COVID-19-related deaths in the intervention group compared to three cases of severe COVID-19 and two deaths in the placebo group.

There were no safety concerns, as the treatment was well-tolerated and adverse events were balanced between groups, the manufacturer said.

Importantly, 75% of the trial population had comorbidities, including being "at risk of an inadequate response to active [immunization]," such as older adults and those with immunosuppressive disease or on immunosuppressive medication.

"With these exciting results, AZD7442 could be an important tool in our arsenal to help people who may need more than a vaccine to return to their normal lives," the trial's principal investigator, Myron Levin, MD, of the University of Colorado School of Medicine, said in a statement.

AZD7442 was derived from the B cells of convalescent patients. PROVENT was a phase III randomized trial conducted at 87 sites in the U.S., U.K., Spain, France, and Belgium. Participants were adults "who would benefit from prevention" with the long-acting antibody, were unvaccinated at the time of enrollment, and were negative for SARS-CoV-2 via serology testing.

Overall, 5,197 were randomized 2:1 to receive a single 300 mg dose of AZD7442 or placebo. AstraZeneca noted that 43% of participants were ages 60 and older. Comorbidities included diabetes, severe obesity or cardiac disease, COPD, chronic kidney disease, and chronic liver disease. About 73% were white.

The company noted that the drug is active in lab studies against emerging strains, including the Delta variant.

Primary efficacy endpoint was the first case of SARS-CoV-2 symptomatic illness confirmed via RT-PCR that occurred post-dose prior to day 183, though subjects are slated to be followed for 15 months, AstraZeneca said.

The manufacturer plans to submit the full results for peer-reviewed publication, while trials of the antibody continue for both treatment and prevention.

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    Molly Walker is deputy managing editor and covers infectious diseases for . She is a 2020 J2 Achievement Award winner for her COVID-19 coverage.