The UK-based multinational pharmaceutical company AstraZeneca’s late-stage trial failed to provide evidence that its COVID-19 antibody therapy protected people who had contact with an infected person from the disease, creating a small setback in its efforts to find alternatives to vaccines.
The study examined whether the therapy, a cocktail of two types of antibodies, could prevent adults who had been exposed to the virus in the past eight days from developing COVID-19 symptoms.
The treatment has been undergoing phase 3 or final clinical trials to assess its safety and efficacy. AstraZeneca said that 1,121 unvaccinated adults had been exposed to an infected person as part of the trial.
The therapy, AZD7442, was 33 percent effective in lowering the risk of people developing symptoms compared with a placebo, but that result was not statistically significant which means it might have been due to chance and not the therapy.
The vast majority, though not all, were free of the virus at the start of the trial. Results for a subset of participants who were not infected, to begin with, were more encouraging but the primary analysis rested on results from all participants.
“While this trial did not meet the primary endpoint against symptomatic illness, we are encouraged by the protection seen in the PCR negative participants following treatment with AZD7442,” AstraZeneca’s Executive Vice-President Mene Pangalos said in a statement.
AstraZeneca is still continuing trials to assess whether the drug can prevent COVID-19 or treat more severe symptoms. The company is banking on further studies to revive the product’s fortunes. Five more trials are ongoing, testing the antibody cocktail as treatment or in prevention.
The next one will likely be from a larger trial testing the product in people with a weakened immune system due to cancer or an organ transplant, who may not benefit from a vaccine.
AZD7442 belongs to a class of drugs called monoclonal antibodies which mimic natural antibodies produced by the body to fight off infections. Similar therapies developed by rivals Regeneron and Eli Lilly have been approved by US regulators for treating un-hospitalized COVID patients.
European regulators have also authorized Regeneron’s therapy and are reviewing those developed by partners GlaxoSmithKline and Vir Biotechnology as well as by Lilly and Celltrion. Regeneron is also seeking US authorization for its therapy as a preventative treatment.
However, AstraZeneca’s result is a small blow for the drug industry as it tries to find more targeted alternatives to COVID-19 vaccines, particularly for people who may not be able to get inoculated or those who may have an inadequate response to vaccination.