Pfizer Begins Phase 2/3 Study of COVID-19 Treatment Paxlovid in Children

Pfizer Inc. said it has initiated a phase 2/3 study called EPIC-PEDS to evaluate the efficacy, pharmacokinetics, and safety of nirmatrelvir [PF-07321332] tablets, at the 300 mg dose, and ritonavir tablets, at the 100 mg dose, (Paxlovid) in non-hospitalized, symptomatic pediatric individuals with a confirmed diagnosis of COVID-19, who are at risk of progression to severe disease.

“Since the beginning of the pandemic, more than 11 million children under the age of 18 in the United States alone have tested positive for COVID-19, representing nearly 18% of reported cases and leading to more than 100,000 hospital admissions. 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 hospitalization or death,” Mikael Dolsten, chief scientific officer and president of worldwide research and development and medical at Pfizer, said in a statement.

The phase 2/3 trial is a multi-label, open-label, single-arm study in approximately 140 individuals who are younger than aged 18 years. The enrollment included 2 cohorts: 1 with individuals aged 6 to 17 years weighing at least 88 lbs. and the second with participants aged 6 to 17 years weighing more than 44 lbs. and less than 88 lbs.

In the first cohort, participants received Paxlovid orally twice a day for 5 days, which is the authorized dosing for pediatric individuals aged 12 years and older who weigh at least 88 lbs.

In the second cohort, individuals received the same dosing orally twice a day for 5 days.

Additionally, Pfizer said in the statement that it is working to develop an age-appropriate formulation for 3 additional planned cohorts of individuals younger than aged 6 years- and will enroll the trial to include these younger age groups.

Data from the phase 2/3 study of high-risk, non-hospitalized adults with COVID-19 showed that Paxlovid reduced the risk of death or hospitalization by about 89%, within 3 days of symptom onset compared with the placebo.

Additionally, Paxlovid reduced the risk of death or hospitalization by approximately 88% within 5 days of symptom onset compared with the placebo.

There were no deaths observed in the treatment group.

Treatment-emergent adverse events were comparable in Paxlovid and the placebo and were mainly mild in intensity.

The effectiveness and safety of Paxlovid has not been established in children, though the FDA did authorize Paxlovid for emergency use for individuals aged 12 years or older who weigh at least 88 lbs.

The pharmacokinetic-pharmacodynamic determined that the authorized adult dosing regimen would result in comparable blood concentration levels of Paxlovid in this population and with adults of similar body weight included in the EPIC-HR trial

Data from the EPIC-PEDS study will prove further support for those dose recommendations in this population, as well as potentially expand the indication to individuals who weigh less and are younger, Pfizer said.

Paxlovid is approved or authorized in more than 50 countries.

Reference

Pfizer initiates phase 2/3 study of novel COVID-19 oral treatment in pediatric participants. Pfizer. News release. March 9, 2022. Accessed March 10, 2022. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-initiates-phase-23-study-novel-covid-19-oral