Pfizer releases additional data on new drug to treat COVID symptoms
Pfizer Inc. shared data from the Phase 2/3 EPIC-SR (Evaluation of Protease Inhibition for COVID-19 in Standard-Risk Patients) study evaluating the use of PAXLOVID (nirmatrelvir [PF-07321332] tablets and ritonavir tablets) in patients who are at standard risk for developing severe COVID-19.
In previously reported interim analyses, the company disclosed that the novel primary endpoint of self-reported, sustained alleviation of all symptoms for four consecutive days was not met, and a non-significant 70% relative risk reduction was observed in the key secondary endpoint of hospitalization or death. An updated analysis from 1,153 patients enrolled through December 2021 showed a non-significant 51% relative risk reduction. A sub-group analysis of 721 vaccinated adults with at least one risk factor for progression to severe COVID-19 showed a non-significant 57% relative risk reduction in hospitalization or death.
Additional analyses of secondary endpoint data showed that treatment with PAXLOVID resulted in a nominally significant 62% decrease in COVID-19-related medical visits per day across all patients, relative to placebo Types of medical visits included trips to the emergency room, urgent care, hospital admissions, and telehealth calls, among others. This observation is consistent with data from a secondary endpoint of the EPIC-HR1 study, which showed a 67% reduction in medical visits per day versus placebo. An additional pre-specified descriptive analysis showed a 72% reduction in the average number of days in hospital among PAXLOVID-treated patients versus placebo in EPIC-SR. Other not statistically significant findings included no PAXLOVID-treated patients admitted to the intensive care unit, compared to three in the placebo group, and no deaths in patients who received PAXLOVID with one death in the placebo group.
“Results from our Phase 2/3 EPIC-HR and EPIC-SR studies, as well as post-authorization experience, support the efficacy and safety profile for PAXLOVID in the treatment of mild-to-moderate COVID-19 patients with at least one risk factor for progressing to severe COVID-19, regardless of vaccination status,” said Albert Bourla, Chairman and Chief Executive Officer, Pfizer. “With up to 40-50% of people around the world estimated to be high risk, we believe there remains a significant unmet need for treatment options to help combat this disease, and we will continue to prioritize efforts to advance the development of PAXLOVID.”
Treatment-emergent adverse events were comparable between PAXLOVID (23.1%) and placebo (23.4%), most of which were mild in intensity. Rates of serious adverse events (1.4% vs. 1.9%) and discontinuation of study drug due to adverse events (1.7% vs. 1%) were also comparable between PAXLOVID and placebo.
Due to a very low rate of hospitalization or death observed in the standard-risk patient population, Pfizer has decided to cease enrollment into EPIC-SR and include available data in this month’s planned New Drug Application (NDA) submission to the U.S. Food and Drug Administration (FDA) to support the use of PAXLOVID in appropriate individuals at high risk of progression to severe illness.2 The company will focus efforts on generating further data on PAXLOVID in vulnerable populations, including longer treatment durations in immunocompromised individuals, as well as exploring other clinical development opportunities, such as its potential use in hospitalized patients with severe disease.
The results from these additional analyses are not expected to impact Pfizer’s full-year 2022 revenue guidance. Analyses of the data are ongoing, and final results will be made available via publication or presentation.
PAXLOVID is currently approved or authorized for conditional or emergency use in more than 65 countries across the globe to treat high-risk COVID-19 patients. Available safety data for PAXLOVID have been generally consistent in more than 3,500 PAXLOVID-treated participants across the EPIC-HR, EPIC-SR and EPIC-PEP3 studies, as well as in reported post-authorization safety experience.
