WHO adds Pfizer’s 2-drug antiviral Paxlovid to Covid recommendations for high-risk patients

WHO Guideline Development Group recommends oral drug Paxlovid for patients with non-severe Covid-19 who are at high risk of hospitalisation.

Pfizer’s Paxlovid is a combination of two antivirals | Pixabay

New Delhi: The World Health Organization (WHO) has included Pfizer’s Paxlovid, a combination of two antivirals — nirmatrelvir and ritonavir — in its list of recommended drugs for Covid patients at high risk of hospital admission.

The WHO Guideline Development Group has recommended the oral drug for patients with non-severe Covid-19 who are at high risk of hospitalisation. This includes patients who are unvaccinated, older, or immunosuppressed.

In an article published in the BMJ Friday, experts explained that the nirmatrelvir-ritonavir combination represents a “superior choice” for high-risk patients because it may prevent more hospitalisations than the alternatives, has fewer potential harms than the antiviral drug molnupiravir, and is easier to administer compared to intravenous options such as remdesivir and antibody treatments.

However, they add that the drug’s benefits are trivial in patients at a lower risk of severe disease.

The drug has not been recommended for patients with severe or critical Covid-19 owing to the absence of trial data on nirmatrelvir and ritonavir for this focus group.

In December last year, the US Food and Drug Administration (FDA) granted emergency-use authorisation (EUA) for Paxlovid for treatment of mild-to-moderate cases of Covid-19 in patients over 12 years of age and weighing at least 40 kg.

Paxlovid recommendation based on trials

Antiviral drugs nirmatrelvir and ritonavir are known as protease inhibitors. Proteases are enzymes that help break down proteins into smaller functional units in viruses, allowing them to infect a cell.

The WHO’s recommendation for Paxlovid is based on data from two randomised controlled trials involving 3,100 patients. The trials showed that for every 1,000 patients, Paxlovid led to 84 fewer hospital admissions. In addition, the drug posed minimal or no risk of adverse effects that might result in discontinuation of the drug.

However, the drug could not bring about any important improvement in terms of mortality.

The recommendations are part of ‘living guidelines’ developed by the WHO with support from MAGIC Evidence Ecosystem Foundation, to provide guidance on the management of Covid-19 and help doctors make better decisions with their patients.

Living guidelines allow researchers to update previously vetted and peer-reviewed evidence summaries in line with the emergence of new information.

Remdesivir for patients with non-severe Covid

As part of its update to the guidelines, the WHO also made a conditional recommendation, endorsing antiviral drug remdesivir for patients with non-severe Covid-19 who are at high risk of hospitalisation.

This recommendation is based on new data from five randomised controlled trials involving 2,700 patients. It supplants a previous recommendation against the use of remdesivir for treatment of patients with Covid-19, regardless of severity of the disease.

The panel noted that antiviral drugs should be administered as early as possible in the course of the disease.

However, the panel also asserted that there is uncertainty regarding the risk of emergence of drug resistance, which refers to a situation where the virus mutates to become resistant to drugs.

Changes to the guidelines made by the WHO Friday add to previous conditional recommendations for the use of molnupiravir for high-risk patients with non-severe Covid-19 and sotrovimab — a monoclonal antibody treatment — for select patients.

(Edited by Amrtansh Arora)