Pfizer seeks FDA EUA for oral antiviral pill to treat Covid-19

Pfizer has sought Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) for its experimental oral antiviral pill, Paxlovid (PF-07321332; ritonavir), to treat individuals with mild-to-moderate Covid-19.

Paxlovid is intended for Covid-19 patients who are at higher risk of hospitalisation or mortality.

PF-07321332 can potentially hinder the SARS-CoV-2-3CL protease activity, which is an enzyme needed for viral replication.

Pfizer noted that PF-07321332 is administered along with a low dose of ritonavir to decelerate the metabolism or breakdown of the drug.

This allows it to be active in the body for an extended duration at greater concentrations to fight the virus.

The latest EUA submission is based on positive interim analysis data from the Phase II/III EPIC-HR clinical trial.

The trial enrolled adult Covid-19 patients aged 18 years and above who were not hospitalised but at the greater disease progression risk.

Findings showed that Paxlovid showed an 89% decline in Covid-19-associated hospitalisation or mortality risk from any cause versus placebo within three days of symptom development.

No cases of death were reported in the Paxlovid arm with comparable results observed within five days of symptom development.

Furthermore, mild treatment-emergent adverse events were reported in the trial, which were similar between the Paxlovid and placebo arms.

On obtaining favourable efficacy data, the independent Data Monitoring Committee of the trial had recommended stopping subject enrolment.

In October, the company initiated a rolling submission of non-clinical data to the US FDA for the drug while submissions are underway in various nations including in the UK, New Zealand, South Korea and Australia.

Pfizer chairman and CEO Albert Bourla said: “The overwhelming efficacy achieved in our recent clinical study of Paxlovid and its potential to help save lives and keep people out of the hospital if authorised, underscores the critical role that oral antiviral therapies could play in the battle against Covid-19.

“We are moving as quickly as possible in our effort to get this potential treatment into the hands of patients and we look forward to working with the US FDA on its review of our application, along with other regulatory agencies around the world.”

In a separate development, Pfizer has entered a voluntary licensing agreement with the United Nations (UN)-backed public health organisation Medicines Patent Pool (MPP) for Paxlovid.

The deal will aid MPP to enable further manufacturing and supply of the oral antiviral on obtaining authorisation or approval by proving sub-licenses to eligible generic drug manufacturers.