Oral drug for COVID-19 treatment significantly reduced hospitalization and death: Study
USA: A new oral drug candidate for COVID-19 treatment, Paxlovid, was shown to significantly reduce hospitalization and death in adult patients, according to Pfizer, and will be submitted for an emergency use authorization in the US. Pfizer has announced the results of clinical trials of its new oral antiviral treatment against COVID-19.
According to results released by the pharmaceutical company Pfizer on November 5, 2021, the new drug candidate, Paxlovid, proved to be effective against the SARS-CoV-2 virus, which causes COVID-19.
The study, published in the journal Science, found that Paxlovid (PF-07321332; ritonavir) reduced the risk of hospitalization or death by 89% compared to placebo in non-hospitalized high-risk adults with COVID-19. In the overall study population through Day 28, no deaths were reported in patients who received Paxlovid as compared to 10 deaths in patients who received placebo.
The Phase 2/3 EPIC-HR study began enrollment in July 2021. The Phase 2/3 EPIC-SR (Evaluation of Protease Inhibition for COVID-19 in Standard-Risk Patients) and EPIC-PEP (Evaluation of Protease Inhibition for COVID-19 in Post-Exposure Prophylaxis) studies, which began in August and September 2021 respectively, were not included in this interim analysis and are ongoing.
The primary analysis of the interim data set evaluated data from 1219 adults who were enrolled by September 29, 2021. At the time of the decision to stop recruiting patients, enrollment was at 70% of the 3,000 planned patients from clinical trial sites across North and South America, Europe, Africa, and Asia, with 45% of patients located in the United States. Enrolled individuals had a laboratory-confirmed diagnosis of SARS-CoV-2 infection within a five-day period with mild to moderate symptoms and were required to have at least one characteristic or underlying medical condition associated with an increased risk of developing severe illness from COVID-19. Each patient was randomized (1:1) to receive PAXLOVID™ or placebo orally every 12 hours for five days.
The scheduled interim analysis showed the following findings:
- There was a 89% reduction in risk of COVID-19-related hospitalization or death from any cause compared to placebo in patients treated within three days of symptom onset (primary endpoint); 0.8% of patients who received Paxlovid were hospitalized through Day 28 following randomization (3/389 hospitalized with no deaths), compared to 7.0% of patients who received placebo and were hospitalized or died (27/385 hospitalized with 7 subsequent deaths). The statistical significance of these results was high.
- Similar reductions in COVID-19-related hospitalization or death were observed in patients treated within five days of symptom onset; 1.0% of patients who received Paxlovid, were hospitalized through Day 28 following randomization (6/607 hospitalized, with no deaths), compared to 6.7% of patients who received a placebo (41/612 hospitalized with 10 subsequent deaths), with high statistical significance.
- In the overall study population through Day 28, no deaths were reported in patients who received Paxlovid, as compared to 10 (1.6%) deaths in patients who received placebo.
If approved or authorized, Paxlovid, which originated in Pfizer's laboratories, would be the first oral antiviral of its kind, a specifically designed SARS-CoV-2-3CL protease inhibitor. Upon successful completion of the remainder of the EPIC clinical development program and subject to approval or authorization, it could be prescribed more broadly as an at-home treatment to help reduce illness severity, hospitalizations, and deaths, as well as reduce the probability of infection following exposure, among adults. It has demonstrated potent antiviral in vitro activity against circulating variants of concern, as well as other known coronaviruses, suggesting its potential as a therapeutic for multiple types of coronavirus infections.
"All of us at Pfizer are incredibly proud of our scientists, who designed and developed this molecule, working with the utmost urgency to help lessen the impact of this devastating disease on patients and their communities," Mikael Dolsten, MD, PhD., Chief Scientific Officer and President, Worldwide Research, Development and Medical of Pfizer said in a press release. "We're thankful to all of the patients, investigators, and sites around the world who participated in this clinical trial, all with the common goal of bringing forth a breakthrough oral therapy to help combat COVID-19."
The study titled, "An oral SARS-CoV-2 Mpro inhibitor clinical candidate for the treatment of COVID-19," is published in the journal Science.