Evusheld, how it works and when the new drug that prevents Covid arrives

The EMA had started its so-called continuous review already in mid-October. But it has not yet provided an opinion or conditional marketing authorization. The countries, however, can proceed independently and in fact on 20 January the decree of the Ministry of Health was published in the Official Gazette with which Evusheld, we are talking about, is authorized for use in prophylaxis. The pharmaceutical company is AstraZeneca.

The decree stated that the Technical Scientific Advisory Commission (CTS) of Aifa, obviously after having analyzed all the available documentation, had resolved that, “in consideration of the at least partial maintenance of the efficacy of Evusheld against the Omicron variant, as well as its long duration of action (at least six months), it may be useful to have this option in the current pandemic phase for pre-exposure prophylaxis “. The provision entrusted the distribution to the extraordinary Commissioner and to AIFA itself the definition of terms and conditions of use.

Now there we are and apparently Italy would have required an initial quantity of the double monoclonal antibody from 20 thousand doses. The first should be within this month delivered to the regions, as Liguria has confirmed for example. It is in fact the first preventive drug especially intended for people who they cannot be vaccinated or in which the vaccine could fail to generate an adequate immune response. From patients undergoing chemotherapy to those who have to take anti-rejection drugs after an organ transplant to the immunosuppressed. The same for which, according to Ema, the fourth dose (or second booster) is already recommended.

How Evusheld works

The medicine consists of two monoclonal antibodies, tixagevimab And cilgavimabdeveloped al Vanderbilt University Medical Center of Nashville, Tennessee. A monoclonal antibody, it must be remembered, is a type of protein designed to recognize and bind to a specific structure (called an antigen). Tixagevimab and cilgavimab were designed to bind to the SARS-CoV-2 spike protein at two different sites. By binding to the spike protein, wrote Aifa, «it is expected that prevent the virus from entering the body’s cells and cause infection. Since the antibodies bind to different parts of the protein, their use in combination may be more effective than their use alone ».

In the United States, the drug is authorized in emergency for people over 12 years old and weighing at least 40 kilograms. Not enough: individuals who can receive this treatment must have moderately or severely compromised immune systems due to a medical condition or as mentioned by taking immunosuppressive medicines or for other treatments that may prevent an adequate response to vaccines. Or they have to be people who they cannot be vaccinatedfor example for previous adverse reactions to a Covid-19 vaccine and / or components of such vaccines.

One dose of Evusheld, given through two separate consecutive intramuscular injections (a monoclonal antibody injection, given in immediate succession), may be effective for prevention before exposure for six months. Warning: the drug, in the United States as well as in Italy, is not authorized for people for the treatment of Covid-19 or for post-exposure prevention like other monoclonals. But, in both cases, only for prophylaxis in the subjects indicated above.

According to AstraZeneca Evusheld reduces the risk of developing symptomatic disease by 83% for at least six months after a single dose. The numbers come from the Phase 3 study of approximately 5,300 individuals. As for the tightness of the protection, however, further follow-up studies are needed. Other independent investigations have also confirmed the ability of the two antibodies that make up the cocktail to neutralize not only the previous variants but also Omicron.

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