FILE PHOTO. Pfizer shows the making of its experimental Covid-19 antiviral pills, Paxlovid. © AFP / Pfizer
Pfizerís Paxlovid tablets against Covid have been given emergency use authorization by the US Food and Drug Administration (FDA). The first pill treatment of this kind, it can be prescribed to high-risk patients aged 12 and older.
"Todayís authorization introduces the first treatment for [Covid]-19 that is in the form of a pill that is taken orally - a major step forward in the fight against this global pandemic," said Dr. Patrizia Cavazzoni, director of the FDAís Center for Drug Evaluation and Research.
The combination of nirmatrelvir and ritonavir packaged for oral use will be available to treat mild-to-moderate Covid-19 in people who test positive and are at "high risk for progression to severe" disease, including hospitalization or death, the FDA said on Wednesday.
The drug is available by prescription only, and should be taken as soon as possible after diagnosis, and within five days of the onset of symptoms. It is not authorized for pre-exposure or post-exposure prevention, however, nor is it considered a substitute for vaccination.
According to the agency, the treatment is meant to last no longer than five days and consists of three pills: two tablets of nirmatrelvir and one of ritonavir taken twice daily. Nirmatrelvir is intended to stop the virus from replicating, and ritonavir slows the first drugís breakdown to enable it to last longer.
While there are "no adequate, approved, and available alternatives" to Paxlovid, the FDA does warn that there are possible side effects. In addition to a risk of "impaired sense of taste, diarrhea, high blood pressure, and muscle aches," there is potential for "significant" drug interactions with certain HIV medications. Paxlovid is also not recommended for people with liver and kidney impairments, as ritonavir may cause liver damage. The FDA has published a full list of potential drug interactions in a guide for healthcare providers.
The approval is based on a double-blind clinical trial of patients who had not been vaccinated or previously contracted Covid-19. According to the study, Paxlovid reduced Covid-related hospitalization or death by 88% compared to the placebo.
The White House has already announced it has purchased 10 million doses of the Paxlovid treatment, as well as three million doses of Merckís Lagrevio, a molnupiravir-based pill, which is also expected to get the green light from the FDA this week.