Passive vaccination? AstraZeneca spotlights six-month protection with Covid-19 antibody among vulnerable group
New follow-up data suggest that AstraZeneca’s long-acting antibody can protect high-risk populations from contracting Covid-19 for as long as six months, beefing up the case for it as a form of “passive immunization” or “passive vaccination.”
At a six-month cutoff for the Phase III PROVENT trial, investigators tracked an 83% reduction in risk of symptomatic Covid-19 after one dose of the antibody among 4,991 volunteers. The company did not spell out case counts on either arm, noting only that there were no severe disease or Covid-related deaths in the AZD7442 arm and two additional cases of severe Covid-19 in the placebo arm (for a total of five severe cases and two related deaths).
Coming almost two months after the initial readout, the update was released alongside a new analysis of the TACKLE trial, which tested AZD7442 as a treatment and showed that, when given within three days of symptom onset, it can cut the risk of severe disease or death by 88% — a significant leap from the previously reported 50% number when treatment was given within seven days.
Together, AstraZeneca said, they paint a fuller picture of AZD7442, which it had first licensed from Vanderbilt, as an important addition to the arsenal.
“AZD7442 is the only long-acting antibody with Phase III data to demonstrate benefit in both pre-exposure prophylaxis and treatment of COVID-19 with one dose,” said Mene Pangalos, EVP of biopharma R&D in a statement.
In a recent interview with Endpoints News, Pangalos emphasized how the drug’s long-acting property sets it apart from other antibodies. Eli Lilly, Regeneron and Vir/GlaxoSmithKline have all nabbed emergency use authorizations for their therapies, with an uptick in use amid new surges due to the Delta variant and breakthrough cases.
“Others are talking about prophylaxis, but they’re talking about monthly administration,” he said. “We’re talking about, potentially, at a maximum twice a year, I’m hoping it’ll be once a year. And so almost in a way be, you know, passive immunization or passive vaccination.”
The FDA is currently reviewing an EUA filing in the prophylactic setting.
It’s especially relevant when you consider that PROVENT sought to enroll participants who are immunocompromised — people with multiple sclerosis, say, or cancer. These people, estimated to make up about 2 to 3% of the population, are thought to be less protected by vaccination.
“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,” said Hugh Montgomery, principal investigator and professor of intensive care medicine at University College London.
On the treatment side, TACKLE similarly targeted patients at high risk of progression to severe Covid-19 for enrollment — with 90% of participants in that category. Again, there was no breakdown on the number of cases in each group.
The new, exploratory analysis suggested that when given sooner after symptom onset, a single dose of AZD7442 could better prevent those severe outcomes much better than placebo among non-hospitalized patients. “You could treat with an oral antiviral, that’s great,” Pangalos said. “Now, you could treat with an antibody, or you could treat with ours down the road as well, and you won’t just be treated for the two weeks that you’ve got the symptoms. You’ll be treated the next 12 months in terms of prevention.”
In a Q&A call this morning, CEO Pascal Soriot confirmed that plans for a pediatric trial are underway. And in terms of pricing, what that will look like hasn’t been determined yet — EVP Iskra Reic only said they are pursuing a “commercial pricing strategy.”
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