THE FOOD and Drug Administration in the Philippines has given Emergency Use Authorization (EUA) to Pfizer’s novel COVID-19 oral treatment called Paxlovid. It is the first oral treatment of its kind; it includes nirmatrelvir, a 3CL (or main) protease inhibitor that was specifically designed to combat SARS-CoV-2.
Data demonstrated an 89% and 88% reduction in risk of COVID-19-related hospitalization or death from any cause in adults treated with Paxlovid within three and five days of symptom onset, respectively, compared to placebo.
“This milestone in the Philippines is an important moment in our continued fight against COVID-19, paving the way for use of Paxlovid as we address the threat of a new variant of concern, Omicron. We are honored to have been working with the FDA Philippines and want to commend them for their fast-track assessment of Paxlovid to grant the Emergency Use Authorization,” said Edilberto Reyes, Pfizer Philippines Interim Country Manager.
Positive results
FDA Philippines based its decision on positive results from the Phase 2/3 EPIC-HR (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients) interim analysis, which enrolled non-hospitalized adults with confirmed COVID-19 who were at increased risk of progressing to severe illness.
The data showed that Paxlovid reduced the risk of hospitalization or death by 89% (within three days of symptom onset) and 88% (within five days of symptom onset) compared to placebo, with no deaths observed in the treatment group. Treatment-emergent adverse events were comparable between Paxlovid (23%) and placebo (24%), most of which were mild in intensity.
Treatment-emergent adverse events were comparable between Paxlovid (23%) and placebo (24%), most of which were mild in intensity. These data were recently published in the New England Journal of Medicine. Additional Phase 2/3 clinical trials are ongoing in adults at standard risk (i.e., low risk of hospitalization or death) of progressing to severe illness, and in those who have been exposed to the virus through household contacts.
About Paxlovid
About Nirmatrelvir 150 mg / Ritonavir 100 mg (Paxlovid) Film-Coated Tablets, Paxlovid is a SARS-CoV-2 main protease (Mpro) inhibitor (also known as SARS-CoV2 3CL protease inhibitor) therapy. It was developed to be administered orally so that it can be prescribed at the first sign of infection or, pending clinical success of the rest of the EPIC development program and subject to regulatory authorization, at first awareness of an exposure – potentially helping patients avoid severe illness (which can lead to hospitalization and death) or avoid disease development following contact with a household member who contracts COVID-19.
Nirmatrelvir [PF-07321332], which originated in Pfizer laboratories, is designed to block the activity of the Mpro, an enzyme that the coronavirus needs to replicate. Co-administration with a low dose of ritonavir helps slow the metabolism, or breakdown, of nirmatrelvir for it to remain active in the body for longer periods at higher concentrations to help combat the virus.
Nirmatrelvir is designed to inhibit viral replication at a stage known as proteolysis, which occurs before viral RNA replication.
Current variants of concern can be resistant to treatments that work by binding to the spike protein found on the surface of the SARS-CoV-2 virus. Paxlovid, however, works intracellularly by binding to the highly conserved Mpro of the SARS-CoV-2 virus to inhibit viral replication. Nirmatrelvir has shown consistently in vitro antiviral activity against earlier and current variants of concern (i.e., Alpha, Beta, Delta, Gamma, Lambda, Mu, and Omicron).
Paxlovid is authorized to be administered at a dose of 300 mg (two 150 mg tablets) of nirmatrelvir with one 100 mg tablet of ritonavir, given twice daily for five days. One carton contains five blister packs of Paxlovid, as co-packaged nirmatrelvir tablets with ritonavir tablets, providing all required doses for a full five-day treatment course.
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Cheryl M. Luis is the wife of George N. True II. Like her husband, she advocates health and lifestyle writing and vows to continue “Health Frontiers” as her husband’s legacy./PN
