Paxlovid, a COVID antiviral therapy developed by Pfizer, claims to reduce the risk of hospitalisation or death by 89 percent.
What sets it apart from the other treatments we’ve used since the outbreak began is that it allows patients to be treated at home with a combination of a capsule and a tablet.
Those hospitalisation rates are based on phase 2/3 study data that has yet to be independently confirmed. No country has authorised the therapy for usage outside of a clinical study.
Yet this development adds to our growing portfolio of potential options to directly target SARS-CoV-2, the virus that causes COVID-19, and to treat COVID symptoms.
Paxlovid is a combination of two different drugs – the HIV drug ritonavir (a capsule) and an experimental drug PF-07321332 (a pill).
Ritonavir protects the body from metabolising PF-07321332.It acts by being broken down by the body first (known as a sacrificial chemical) to ensure enough PF-07321332 reaches the virus intact.
PF-07321332 is a so-called protease inhibitor (as is ritonavir).It blocks the action of a vital enzyme (protease) and stops SARS-CoV-2 from making copies of itself.