Singapore approves 2nd oral drug, molnupiravir, for COVID-19 treatment

·Editorial Team
·4 min read
Molnupiravir, or Lagevrio, has been granted interim authorisation under the pandemic special access route. (Merck & Co via Reuters file photo)
Molnupiravir, or Lagevrio, has been granted interim authorisation under the pandemic special access route. (Merck & Co via Reuters file photo)

SINGAPORE — A second oral antiviral drug has been authorised for the treatment of mild to moderate COVID-19 in those aged 18 years and above in Singapore, the Health Sciences Authority (HSA) announced on Tuesday (19 April).

Molnupiravir, or Lagevrio, has been granted interim authorisation under the pandemic special access route, said the HSA in a statement, in consultation with its medicines advisory committee.

The medicine can be used for those who are at risk of progressing to severe COVID-19 or hospitalisation, or both, and whom alternative treatment options are not clinically appropriate, it added.

It should be administered within five days of the onset of symptoms, for a duration of five days. It will be prescribed and prioritised to those at higher risk of severe COVID illness, as directed by the Ministry of Health (MOH).

The common adverse events of molnupiravir reported in the clinical studies include diarrhoea, nausea and dizziness which were generally mild, HSA said.

However, it added that molnupiravir is not recommended for use in pregnant women, lactating mothers, and those below 18 years old.

Women of childbearing potential should use a reliable method of contraception for the duration of treatment and for four days after the last dose of molnupiravir. Men with partners of childbearing potential should use reliable contraceptive methods during treatment and for at least three months after the last dose.

"These recommendations are based on findings from animal studies which showed that (molnupiravir) may affect foetal growth, bone and cartilage development, and DNA," said HSA.

How effective is molnupiravir?

Molnupiravir was co-developed by pharmaceutical firm Merck in the United States and Canada – also known as Merck Sharp & Dohme (MSD) elsewhere in the world – and Ridgeback Biotherapeutics in Miami.

HSA said its review was based on the clinical data from a phase II/III study investigating the use of molnupiravir in reducing the risk of hospitalisation or deaths in patients with mild-to-moderate COVID-19.

The randomised, placebo-controlled study recruited about 1,400 participants aged 18 to 90 who had one or more risk factors for progression to severe COVID-19.

The results showed an efficacy of 30 per cent relative risk reduction with molnupiravir compared to a placebo, the HSA said. Among those who took molnupiravir, 6.8 per cent were eventually hospitalised or died, compared with 9.7 per cent of those who had a placebo.

As of the latest data, there were 48 hospitalisations with two subsequent deaths among those who took molnupiravi and 68 hospitalisations with 12 subsequent deaths in the placebo group, said HSA.

However, in a subgroup of participants who had Sars-CoV-2 antibodies at baseline, a higher proportion of subjects in the molnupiravir group – 3.7 per cent – progressed to hospitalisation or death compared to those in the placebo group –1.4 per cent.

"This is a clinically relevant consideration in Singapore given that most of our population has been fully vaccinated and most would have SARS-CoV-2 antibodies," said HSA.

The authority added that while study results indicated that molnupiravir has lower efficacy compared to other authorised COVID-19 treatments, it may have a place in therapy for patients who are at risk of progressing to severe COVID-19 as well as for whom current available treatment options are clinically inappropriate.

Clinicians must carefully assess that the potential benefits outweigh the risks in the patient before initiating molnupiravir treatment, the HSA said.

MSD is required to submit updated data from ongoing clinical studies to ensure the continued safety and efficacy of molnupiravir for HSA’s continual benefit‐risk assessment, it added.

Second drug after Pfizer's

The first oral antiviral drug granted interim authorisation under the pandemic special access route by HSA was Pfizer's Paxlovid on 3 February.

The drug can be used 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.

On Tuesday, the MOH in a separate statement announced that 16 more Public Health Preparedness Clinics (PHPCs) will be progressively coming on board a pilot programme to prescribe Paxlovid for eligible patients.

This will be in addition to all polyclinics and the 20 PHPCs that are currently participating in the pilot programme.

MOH said it will fully cover the drug cost of Paxlovid use in primary care settings for now, regardless of the patient’s vaccination status, as it can reduce the likelihood of high-risk patients developing severe COVID-19 and requiring hospital admission.

The charging policy for Paxlovid will be reviewed in due course, it added.

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