PLC’s coronavirus antibody treatment failed in late-stage clinical trials to achieve its primary goal of preventing symptomatic Covid-19 in people recently exposed to the virus, the latest disappointment in a broader search for reliable post-infection therapies.
A single dose of the AZD7442 long-acting antibody treatment wasn’t statistically more effective than a placebo in preventing symptomatic Covid-19 in the trial of 1,121 people in the U.K. and U.S., AstraZeneca said Tuesday. The antibody treatment is separate from AstraZeneca’s widely used Covid-19 vaccine developed in partnership with the University of Oxford.
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The trial failure is a major setback for hopes by AstraZeneca and the U.S. of using the drug to treat individuals infected with Covid-19. The drugmaker had received support from the U.S. government potentially exceeding $700 million to develop the treatment and, if successful, to supply hundreds of thousands of doses.
But the results did show potential promise in helping reduce the chances of illness from potential infection in the first place. In a parallel analysis of the same AZD7442 phase-three trial data, the antibody combination showed to be 73% effective in reducing the risk of symptomatic Covid-19 in people who tested negative for evidence of the virus at the time they were dosed with the drug. Though the primary goal was preventing symptomatic Covid-19 after confirmed exposure with an infected person, the company said the treatment could find use in people who aren’t well protected by the range of Covid-19 vaccines, or who are unable or unwilling to take a vaccine.
However, the increasingly broad availability and efficacy of vaccines—with more under development—along with the expected high cost of antibody treatments are likely to limit the demand for vaccine alternatives as a preventive tool.
AstraZeneca said it is continuing to study potential uses for AZD7442 in preventing symptomatic Covid-19. The drug was well-tolerated, with adverse events comparable in the treatment and placebo groups. Of the 1,121 trial participants—all 18 or older and unvaccinated—two-thirds received AZD7442. Of those, 23 developed symptomatic Covid-19, compared with 17 cases in the smaller placebo group. The results failed to show statistically significant efficacy of preventing symptomatic Covid-19 after confirmed exposure, AstraZeneca said.
The success of Covid-19 vaccines, invented and tested at unusually fast speed, has outpaced the development of effective treatments for people after infection, with mixed results from experimental drugs in recent clinical trials.
Combinations of antiviral treatments such as remdesivir, anti-inflammatories and other drugs have been used to target the immune system to reduce severe symptoms and prevent hospitalizations and death.
Some of the drug cocktails have been shown to be effective in reducing viral levels and preventing severe symptoms, but sometimes without clarity about how useful the drug combinations are in younger and lower-risk individuals who are more likely to recover on their own.
AstraZeneca received extensive funding pledges potentially exceeding $700 million from the U.S. government to develop, test and potentially supply up to 700,000 doses of AZD7442 this year. The so-called monoclonal antibodies used were developed by Vanderbilt University Medical Center and licensed to AstraZeneca in June 2020. Monoclonal antibody drugs are designed to mimic the body’s natural antibodies produced by the immune system to fight the coronavirus.
The summarized results were released Tuesday in a company statement. AstraZeneca said it is in discussions with U.S. officials about next steps, and that it intends to publish a fuller version of the results in a peer-reviewed journal. In total, trials of AZD7442 for prevention and treatment of Covid-19 involve more than 9,000 people globally.
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