SINGAPORE - A new oral antiviral drug for treating Covid-19 has been approved for use in Singapore, said the Health Sciences Authority on Thursday (Feb 3).
"This is the first oral tablet approved in Singapore for the treatment of mild to moderate Covid-19 in adult patients who are at high risk of progression to severe disease, to reduce the risk of hospitalisation and death," it added.
Pfizer's drug, Paxlovid, was granted interim authorisation under the HSA's Pandemic Special Access Route (PSAR) on Jan 31.
The authority approved the drug in consultation with its Medicines Advisory Committee.
The drug has to be taken twice daily for five days, and should be given as soon as possible within five days of the onset of Covid-19 symptoms.
HSA said those at higher risk of severe Covid-19 illness will get priority for the drug.
The authority said it has reviewed available clinical data for the drug, and found that it could reduce Covid-19 related hospitalisation or death by 88.9 per cent when given within three days from the onset of symptoms.
The efficacy rate was 87.8 per cent when given within five days of symptoms appearing.
This analysis included patients infected with the Delta variant and lab studies have shown that the drug works against the prevailing variants of concern, including Delta and Omicron variants.
Paxlovid is a combination of two medicines – nirmatrelvir, an antiviral medicine, and ritonavir, which helps keep nirmatrelvir active in the body at higher concentrations for longer to combat the virus.
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Pfizer Singapore on Thursday announced an agreement with Singapore to supply Paxlovid here.
It said in a statement that nirmatrelvir was specifically designed to block the activity of the Sars-CoV-2 3CL enzyme, which the coronavirus needs to replicate.
Pfizer Singapore country manager Erika Pagani said oral treatments help reduce the severity or onset of illness in Covid-19 patients, and could thus be an important tool in addressing the global impact of the pandemic.
HSA noted that there were generally low numbers of cases with side effects in the clinical study.
Common side effects reported were mild to moderate, such as altered sense of taste, diarrhoea, vomiting, hypertension, muscle pain and chills, it added.
The authority said Paxlovid may also interact with various medications such as medicines for irregular heart rate, migraine, and cholesterol, leading to serious side effects.
Some drugs, such as medicines for epileptic seizures, could reduce the level of Paxlovid and lower antiviral efficacy, said HSA, urging doctors prescribing Paxlovid to carefully consider the potential for drug interactions.
Pfizer is required to collect the relevant safety data and monitor the use of its drug as a condition for interim authorisation under PSAR.
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HSA will also requires Pfizer to continue submitting updated data from ongoing clinical studies to ensure the continued safety and efficacy of Paxlovid, such as its efficacy against prevailing variants.
Countries such as South Korea, Britain and Israel have started administering Paxlovid to coronavirus patients from this month.
To ensure poorer countries can use the drug, Pfizer has agreed to allow generic manufacturers to supply versions of Paxlovid to 95 low- and middle-income countries through a licensing agreement with international public health group Medicines Patent Pool.
HSA is currently reviewing molnupiravir, another antiviral pill.
Clinical trials have shown that it can halve the likelihood of dying or being hospitalised, for those at risk of severe illness.
Both Paxlovid and molnupiravir have been approved by the United States’ Food and Drug Administration.
Dr Shawn Vasoo, clinical director of the National Centre for Infectious Diseases, had earlier told The Straits Times that doctors will have to evaluate their patients’ medical history to assess their suitability for Covid-19 treatments.
“Vaccination is still the mainstay for prevention, and the vast majority (who are infected) will do well and not require any specific treatments if they do not have any risk factors for severe disease,” he said.
This article was first published in The Straits Times. Permission required for reproduction.