HSA grants interim authorisation for oral Covid-19 drug molnupiravir

SINGAPORE — The Health Sciences Authority (HSA) on Tuesday (April 19) granted interim authorisation for the use of molnupiravir as an oral treatment for mild to moderate Covid-19.

This decision was made in consultation with HSA's Medicines Advisory Committee, it said in a news release.

Molnupiravir, manufactured by pharmaceutical company MSD, is the second oral antiviral medicine authorised under Singapore’s Pandemic Special Access Route, which paves the way for early access to critical new vaccines, medicines and medical devices during a pandemic.

This means that MSD will be required to submit updated data from ongoing clinical studies, which HSA will actively review.

HSA may also terminate the authorisation at any time, for example, if new data suggests that the benefits no longer outweigh the risks of treatment, it said.

Molnupiravir should be administered within five days of symptom onset for a duration of five days.

It may be used by individuals aged 18 years and above, who are at risk of progressing to severe Covid-19 or hospitalisation, and for people in whom alternative Covid-19 treatment options are not clinically appropriate, the authority said.

However, it will be prescribed to and prioritised for those at higher risk of severe Covid-19 illness after being infected by the Sars-CoV-2 coronavirus, as directed by the Ministry of Health (MOH).

HSA's review of the medicine was based on the clinical data from a combined second- and third-phase study of 1,400 participants between the ages of 18 and 90 who had one or more risk factors for their Covid-19 to become severe.

The study showed an efficacy of 30 per cent relative risk reduction.

Of those who took molnupiravir, 6.8 per had progressed to hospitalisation or death, compared to 9.7 per cent of participants who did not.

However, in a sub-group analysis of participants who had the Sars-CoV-2 antibody at baseline, 3.7 per cent of those who took molnupiravir had progressed to hospitalisation or death, compared to 1.4 per cent who took the placebo. 

"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," HSA said.

"While the 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, and in whom current available treatment options are clinically inappropriate," it added.

"Clinicians must carefully assess that the potential benefits outweigh the risks in the patient before initiating Lagevrio treatment."

Molnupiravir is marketed as Lagevrio.

Dr Aileen Dualan, Asia-Pacific head of medical affairs from MSD, said in a press release by the pharmaceutical company: "Molnupiravir has shown to be effective against a range of variants, and... as an important treatment option for those who are at high risk for progression to severe disease.”

Molnupiravir is not recommended for use in pregnant women, lactating mothers and those below 18 years old.

HSA also said that 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 of molnupiravir, while men with partners of childbearing potential should use reliable contraceptive methods during treatment and for at least three months after the last dose of the drug.

These recommendations are based on findings from animal studies which showed that the drug may affect foetal growth, bone and cartilage development, and DNA.

Side-effects of molnupiravir found in clinical studies include diarrhoea, nausea and dizziness, which were generally mild in intensity, HSA said.

"HSA will actively review post-authorisation safety monitoring data and the data submitted by MSD to ensure that the benefits of molnupiravir continue to outweigh the known risks."

The authority earlier approved Paxlovid on Jan 31 — the first oral antiviral medicine for the treatment of mild to moderate Covid-19 in adult patients with high risk of the coronavirus becoming severe, to reduce the risk of hospitalisation and death.

Separately, MOH announced on April 19 that it will be expanding a pilot programme to prescribe Paxlovid to Covid-19 patients in 16 more Public Health Preparedness Clinics (PHPCs).

The drug is now offered at all polyclinics and 20 PHPCs to Covid-19 patients who are at risk of developing severe disease — such as those with active cancer, serious heart conditions or are on ongoing immunosuppressive condition or treatment — and are assessed by their doctor to be eligible for Paxlovid.