Evusheld is a combination of two long-acting antibodies (tixagevimab and cilgavimab). It’s a drug designed to protect clinically vulnerable people against COVID-19 in cases where vaccines don’t work. A good example is people who have been on the chemotherapy drug Rituximab, which causes much worse COVID-19 outcomes and also reduces vaccine efficacy. Another example is people with primary or secondary immunodeficiency. Evusheld is given prophylactically (that is: in advance) to stop people in this situation developing severe COVID-19 in the first place.
As of 2023, the efficacy of Evusheld against circulating variants has been questioned. On the one hand, in vitro results (in experiments/lab conditions) show reduced neutralisation. On the other hand, real-world studies continue to show protection.
The second version of Evusheld (Sipavibart) is currently being assessed for use by the MHRA with a view to approval for use autumn 2024/early 2025. The reason for a second version of Evusheld is to adapt it so that it is resistant to the latest variants of COVID-19, in a similar way that the vaccinations are adapted to ensure protection from the latest variants on a regular basis.
Pemgarda is also a spike protein-directed attachment inhibitor authorised for emergency use in the US only at the moment for the pre-exposure prophylaxis of COVID-19.