AstraZeneca’s Evusheld reduces the risk of symptomatic COVID-19 by up to 83%
AstraZeneca’s Evusheld reduces the risk of symptomatic COVID-19 by up to 83%

AstraZeneca’s Evusheld reduces the risk of symptomatic COVID-19 by up to 83%

AstraZeneca monoclonal antibody combination tixagevimab-cilgavimab (Evusheld) reduced the risk of symptomatic COVID-19 infection by 83% compared to placebo at a median follow-up of 6 months, a phase 3 randomized clinical trial attempt published yesterday in New England Journal of Medicine.

As part of an ongoing trial, members of the US and European PROVENT study team, which included AstraZeneca representatives, enrolled 5,197 COVID-naïve adults at increased risk of insufficient immune response to COVID-19 vaccination and / or exposure to SARS-CoV 2 at 87 years. sites from November 21, 2020 to March 22, 2021, before the Delta and Omicron variants emerged.

The researchers randomly assigned participants in the 2: 1 ratio to receive an intramuscular 300 milligram dose of either Evusheld (3,460) or a placebo with saline (1,737) and contacted them weekly about any COVID-19 symptoms for up to 183 days.

Infection in 0.2% with Evusheld vs. 1.0% with placebo

Over 73% of participants had an increased risk of infection due to age over 60, obesity, impaired immunity or high risk of vaccine-related side effects, and 77.5% had congestive heart failure, chronic obstructive pulmonary disease or chronic kidney or liver disease.

Among Evusheld recipients, 1,161 (34%) were vaccinated against COVID-19, as were 853 (49%) in the placebo group. The mean age was 53.5 years, 43.4% were 60 years or older, 46.1% were women, 14.5% were Hispanic, 17.3% were black, and 73.0% were white.

Of all participants, 52.5% were considered to be at increased risk for SARS-CoV-2 exposure, including healthcare professionals, meatpackers, military personnel, dormitory students and others living close together in Belgium, France, Spain , The United Kingdom and the United States.

Symptomatic COVID-19 infection occurred in 0.2% of 3,460 Evusheld recipients compared to 1.0% of 1,731 placebo recipients (relative risk reduction, 76.7%; 95% confidence interval [CI]46.0% to 90.0%). After a median of 6 months, the relative risk reduction was 82.8% (95% CI, 65.8% to 91.4%).

“This increase in the efficacy estimate since the time of the primary analysis was driven by a higher percentage of events in the placebo group (1.2%, in 12 out of 960 participants) than in AZD7442 [Evusheld] group (0.1%, in 3 out of 2,003 participants) over 3 to 6 months compared to 0 to 3 months, “the researchers wrote.

Among participants at increased risk of COVID-19 infection or exposure, relative risk reductions (80.7% and 82.6%, respectively) were comparable to those in the overall population in the primary efficacy analysis (76.7%). The time to symptom onset was longer with Evusheld than placebo (hazard ratio, 0.17; 95% CI, 0.08 to 0.33). Serum concentrations of Evusheld remained high for 6 months after receipt.

Five participants, all in the placebo group, developed severe or critical COVID-19, and two died of COVID-19. Six Evusheld recipients (0.2%) and no placebo recipients visited an emergency room with symptoms consistent with COVID-19; three of them were later tested positive for COVID-19, but none were admitted to the hospital.

Low, similar frequencies of adverse events

Among the 3,460 Evusheld recipients, 35.3% reported at least one adverse reaction, most mild or moderate, compared with 34.2% of 1,736 placebo recipients. The most common adverse reaction was injection site reaction, which occurred in 2.4% of the Evusheld group and 2.1% of placebo recipients.

Viral genotypic data for 7 out of 11 symptomatic Evusheld recipients and 13 out of 31 symptomatic placebo recipients showed that 1 in the Evusheld group was infected with the Beta variant and 5 each in the placebo group had an Alpha subvariant or Delta infection .

The study authors noted that an earlier phase 1 attempt of Evusheld compared to serum from COVID-19 survivors, Evusheld recipients had higher SARS-CoV-2 neutralizing antibody levels, which remained three times as high after 9 months. These results were published in January.

“The data reported here support the use of AZD7442 as an immunoprophylaxis to prevent COVID-19,” they wrote, adding that Evusheld has the advantage over other monoclonal antibodies because it provides relatively long-term protection against infection, is given intramuscularly rather than intravenously and is administered only once as two shots instead of every month.

Clinical and pharmacokinetic evaluations of Evusheld in this trial are expected to continue for at least one year, the researchers said.

In December 2021, US Food and Drug Administration (FDA) authorized Evusheld for the prevention of COVID-19 in persons with moderate to severe immunity and those for whom vaccination is not recommended. February 24, FDA recommended increase the dose to 600 mg due to the emergence of the Omicron BA.1 subvariant.

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