AstraZeneca, the British-Swedish pharmaceutical company, had been conducting a trial to assess whether a therapy using a cocktail of two types of antibodies could prevent people –who had been exposed to the coronavirus in the past eight days.– from developing COVID-19. However, it reported on Tuesday that a late-stage trial failed to provide evidence that the therapy could protect people who had come into contact into a COVID-19 infected person.
The therapy, called AZD7442 showed to be 33% effective in reducing the risk of developing COVID-19 symptoms in those exposed as compared to a placebo. The result provided no statistical significance.
The phase III trial conducted by AstraZeneca comprised 1,121 participants from the UK and USA. The majority of the participants were not infected at the beginning of the trial. While a small subset of participants showed encouraging results, the overall efficacy, based on results from all the participants, were not so.
In a statement, Mene Pangalos, Executive Vice President of AstraZeneca, said: “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.”
Nevertheless, the company is planning on further studies to better develop the therapy. There are five more trials that are reportedly ongoing where the antibody cocktail is tested as treatment or prevention. The therapy is also being tried in people with weak immune system due to cancer or an organ transplant. These patients may not benefit from a vaccine and the antibody therapy, if found positive in a large trial, can be an alternative.
AZD7442 uses monoclonal antibodies – artificially produced antibodies in a lab and tailored in a fashion that they become highly effective against the disease these antibodies are prepared for. Antibodies are protein molecules that the defence mechanism (immune system) of our body produces to fight infection.
There are other Monoclonal antibody treatments that have been granted to treat patients with COVID-19. The US regulators have approved such monoclonal antibodies developed by other pharma companies. The monoclonal antibodies developed by Regeneron, Eli Lilly, GlaxoSmithKline(GSK) partnered with Vir have already been approved by US regulators as treatment for those COVID-19 patients who were not hospitalised.
European regulators also have recommended a few antibody therapies. Antibody therapies produced by GSK, Celltrion, Eli Lilly and Regeneron are recommended by European regulators for use in early-stage COVID19 patients who are at a risk of developing a severe condition of the disease.
Monoclonal cocktail therapy has recently got emergency use authorisation in India too. Casirivimab and Imdevimab are the monoclonal antibodies that have been approved by Indian regulator central drugs standard control organisation (CDSCO). The antibody combo has seen a steep price – 59,750 rupees per dose.
The AstraZeneca trial results are not yet published in a peer-reviewed journal. However, the company said that the results will be soon submitted to a journal for peer review.