Pfizer has commenced a Phase II/III clinical trial of its oral therapy Paxlovid (nirmatrelvir [PF-07321332] tablets and ritonavir tablets) for the treatment of paediatric subjects with a confirmed Covid-19 diagnosis.

The EPIC-PEDS trial will enrol nearly 140 non-hospitalised, symptomatic paediatric participants under 18 years old to evaluate Paxlovid, a main protease inhibitor of the SARS-CoV-2 virus.

The multi-center, open-label, single-arm study will assess the therapy’s safety, efficacy and pharmacokinetics in subjects who are at risk for severe disease progression.

Pfizer Worldwide Research, Development and Medical president and chief scientific officer Mikael Dolsten said: “There is a significant unmet need for outpatient treatments that can be taken by children and adolescents to help prevent progression to severe illness, including hospitalisation or death.

“Paxlovid is already authorised or approved in many countries around the world, with more than 1.5 million treatment courses delivered thus far and 30 million expected by July to help combat this devastating disease.”

Cohort 1 of the study will have subjects aged between six and 17 years weighing at least 40kg. They will be given nirmatrelvir/ritonavir 300mg/100mg of the oral therapy two times per day for five days.

In the second cohort, the trial will enrol participants of the same age group but weighing more than 20kg. For five days, they will receive Paxlovid (nirmatrelvir/ritonavir 150mg/100mg) orally two times a day.

Additionally, Pfizer plans to develop an age-appropriate formulation for another three planned cohorts of younger than six years old.

Once data from the first and second cohorts and the new formulation become available, the company will enrol the trial, which will include these age groups.

Safety data of each cohort subjects will be reviewed by an independent Data Monitoring Committee.

In November last year, a Phase II/III clinical trial demonstrated that Paxlovid substantially reduced Covid-19-associated mortality and hospitalisation.