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A chemist at work at AstraZeneca's headquarters. Image Credit: Reuters

Abu Dhabi: The Department of Health – Abu Dhabi in collaboration with Rafed announced last week the signing of the procurement of AstraZeneca’s AZD7442 into the local market. The new and innovative medication is specifically designed to prevent severe infection and death in non-vaccinated, high-risk COVID-19 patients.

Developed by British-Swedish pharmaceutical firm, AstraZeneca’s AZD7442 medication procurement agreement serves to enhance the UAE arsenal against COVID-19.

The agreement was finalised between AstraZeneca, Abu Dhabi health regulator Department of Health (DoH), and Rafed, the country’s group purchasing organisation for essential medical equipment supplies.

Ahead of its use in the UAE, here is all you need to know about the latest therapy:

What kind of medication is AZD7442 and how does it work?

AZD7442, like some of the medications that have proven to be most effective against COVID-19, is also a monoclonal antibody therapy. These are lab-produced antibody molecules that mimic the action of naturally produced antibodies in the human body.

Antibodies or immunoglobulins are specific protein molecules that are naturally generated by the immune system as a defence mechanism against unfamiliar molecules, called antigens. Molecules from pathogens like bacteria and viruses can act as antigens, prompting the production of antibodies that then bind to antigens. These antibodies tell specialised cells of the immune system to kill the invading pathogen.

Lab-generated monoclonal antibodies are immunoglobulins that work specifically against a particular portion on an antigen called the epitope, thus exerting very targeted actions. For example, the SARS-CoV-2 virus’s spike glycoprotein, which sits on its surface, functions to facilitate the virus’s entry into the body’s cells. So SARS-CoV-2 monoclonal antibodies bind to the spike protein and block the virus from entering the cell and reproducing in it.

AZD7442 is a combination of two long-acting antibodies – tixagevimab (AZD8895) and cilgavimab (AZD1061) – derived from white blood cells donated by convalescent patients after SARS-CoV-2 virus infection. Discovered by Vanderbilt University Medical Centre and licensed to AstraZeneca in June 2020, the antibodies bind to distinct sites on the SARS-CoV-2 spike protein, and were optimised by AstraZeneca with half-life extension and reduced immune cell binding, which minimises the risk of antibody-dependent infection and disease.

The therapy is also called Evusheld.

How successful has AZD7442 proven in treating COVID-19?

AZD7442 is the first long-acting antibody with Phase III trial data to demonstrate benefits in both prophylaxis (prevention) and treatment of COVID-19.

In August 2021, AstraZeneca announced high-level results from its PROVENT pre-exposure prophylaxis trial, which showed AZD7442 reduced the risk of developing symptomatic COVID-19 by 77 per cent compared to placebo. Importantly, the trial population with 5,197 participants, included people with co-morbidities who may be in need of additional protection from SARS-CoV-2 infection. More than 75 per cent of participants in PROVENT presented with co-morbidities that are associated with an increased risk of severe disease or a reduced immune response to vaccination. The trial accrued 25 cases of symptomatic COVID-19 at the primary analysis, but the drug was well-tolerated.

Another trial, TACKLE, has seen 50 per cent reduction in severe COVID-19 or death, compared to placebo, in 903 non-hospitalised patients with mild-to-moderate COVID-19 who had had symptoms for seven days or less. The international trial is still ongoing.

AstraZeneca has said that the drug’s half-life extension more than triples the durability of its action, compared to conventional antibodies, and could afford up to 12 months of protection from COVID-19 following a single administration. Trials have shown, however, that it doesn’t help people exposed to the virus from contracting it.

Who is eligible to receive AZD7442?

The specific eligibility will be announced by UAE health authorities once the drug is approved for use. In its procurement announcement, the DoH said the “treatment is specifically designed to prevent severe infection and death in unvaccinated high-risk patients”.

“When approved, the medication will help immunocompromised patients who could not receive a COVID-19 vaccine due to medical reasons and limited autoimmune disorders,” said Dr Jamal Al Kaabi, DoH undersecretary.

Where else is the therapy approved for use?

As it seeks emergency use authorisation in the UAE, AstraZeneca has already applied to the Food and Drug Administration (FDA) for AZD7442 to be used as a preventative drug in the United States. Meanwhile, the European Medicines Agency has also started a real-time review of the therapy.

What other COVID-19 therapies are available in the UAE?

In June 2021, Abu Dhabi became one of the first cities in the world to procure and administer another monoclonal antibody therapy against COVID-19 – Sotrovimab. Developed by GlaxoSmithKline and Vir Biotechnology, the drug was similarly procured under a collaborative agreement with DoH and Rafed, and has since been provided to more than 23,000 patients in the UAE who are aged at least 12 years.

Based on statistics issued in August by the UAE’s National Crisis, Emergencies and Disasters Management Authority (NCEMA), Sotrovimab has prevented fatal complications in recipients by 97 per cent, and prevented the need for hospitalisation among 99.5 per cent of them, Additionally, the duration of hospital stay was reduced by 20 per cent among those who had to be admitted.

Internationally, two other monoclonal antibodies have proven to be effective against COVID-19: Eli Lilly & Co’s bamlanivimab-etesevimab combination therapy for patients with mild-to-moderate COVID-19, and Regeneron and Roche’s single-dose antibody cocktail Ronapreve (known as REGEN-COV in the United States), a combination of casirivimab and imdevimab antibodies.

How has the UAE secured AZD7442 supply?

The UAE is among one of the first countries to secure the medication. It will be procured by Rafed, stored in its massive cold-storage facility in Abu Dhabi, and distributed to healthcare facilities when approved for use.