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expert reaction to press release from AstraZeneca announcing that the AZD7442 PROVENT Phase III prophylaxis trial met primary endpoint in preventing COVID-19

The press release suggests that AZD7442, a combination of two long-acting antibodies, reduced the risk of developing symptomatic COVID-19 by 77% compared to placebo.


Prof Penny Ward, Independent Pharmaceutical Physician, Visiting Professor in Pharmaceutical Medicine at Kings College, London, said:

“This is good news. This antibody combination treatment can be given via an intramuscular (IM) injection which makes it simpler to use in a community setting, as opposed to Ronapreve which is given via intravenous (IV) infusion. In addition it appears to be very long lasting with a single administration potentially offering protection for up to 12 months. This could be very important as an option for patients at high risk from COVID infection who have responded poorly to vaccination or who must take immune-suppressing treatment for other disease (cancer, post-transplant, autoimmune disease etc). Indeed it could potentially be game changing for these individuals, who are currently being advised to continue to shield despite being fully vaccinated.

“The data from both the pre-exposure PROVENT and the post-exposure STORM-CHASER studies are consistent with the mechanism of action of this product. What the storm-chaser trial tells us is that IM injection does not provide an immediate level of antibody sufficient to cut off viral replication and prevent disease among individuals exposed to the virus who are already infected. It was effective among individuals who were PCR negative at the time of treatment, becoming more so 7 days post injection. Two aspects of the trial design might have affected outcomes: firstly treatment could be given up to 8 days after exposure to a known case of COVID which is a long time in terms of infection risk, and in addition, plasma concentrations of the antibody after IM injection will take a while to reach peak. It would be interesting to see if earlier administration using an IV infusion would be more successful than IM injection in this setting. PROVENT demonstrates that passive immunisation works to prevent illness during a community outbreak. These were individuals who were going about their day to day business and not necessarily in close contact with a case, which very significantly increases the risk of becoming infected. This data suggests that the concentrations delivered are good enough in most instances except in the very specific example of direct contact with a known case, when higher concentrations or more immediate exposure are clearly required to prevent infection and illness in the face to prolonged close exposure to a person coughing out the virus.

“These results differ from the other antibody combination post exposure prevention trials in that the IM injection was not as effective in preventing illness for the reasons discussed above. However the prolonged MoA and IM administration are very attractive nonetheless as it offers an additional method to help individuals who may not have responded as well to vaccination to return to more normal life.

“Despite the success of vaccination some individuals do not respond as well and remain at higher risk of disease, hospitalisation and death. Prophylaxis with passive antibody therapy can help these folks further and reduce morbidity and mortality in this important population subset. They can be used to protect people while they undergo cancer treatment for example.

“We have yet to see the results of the COVID patient treatment studies using this antibody combination and data using the combination as an IV infusion. That information would help us to understand relative potency of this vs other antibody cocktails which are coming along the research pathway. In addition, while the data in the press release are encouraging, we need full publication of both studies to be able to understand the merits of this product and how to use it most effectively in practice.”



Declared interests

Dr Penny Ward: “No COIs. I am semi-retired, but I am owner/Director of PWG Consulting (Biopharma) Ltd a consulting firm advising companies on drug and device development. Between December 2016 and July 2019 I served as Chief Medical Officer of Virion Biotherapeutics Ltd, a company developing antiviral treatments for respiratory viral diseases. Previous employee of Roche, makers of tocilizumab (anti IL6 antibody) and CMO of Novimmune, makers of empalumab (anti IFN gamma antibody). These are my personal views and do not reflect those of either institution.”

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