US regulators set to approve oral antiviral against COVID-19
The FDA looks set to authorise Merck’s molnupiravir after its advisory body recommended the antiviral treatment, while Pfizer’s Paxlovid may be next. Oral antiviral treatments that combat the worst effects of COVID-19 are under the regulatory microscope in the US this month.
The group that advises the Food and Drug Administration (FDA) voted to recommend Merck/MSD’s antiviral molnupiravir, which means the treatment could be authorised and made available to patients within weeks.
The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) became the first regulatory agencies to approve the drug in early November 2020. Merck developed molnupiravir with Ridgeback Biotherapeutics.
“With the continued spread of the virus and the emergence of variants, additional treatments for COVID-19 are urgently needed,” said Dr Dean Y Li, president of Merck Research Laboratories. “That is why we are moving with speed and rigor to pursue authorisations and to accelerate broad global access to this investigational medicine.”
The data behind molnupiravir is from the phase 3 MOVe-OUT clinical trial in non-hospitalised adult patients with mild to moderate COVID-19 who were at high risk of severe disease. The drug significantly reduced hospitalisations and death; 14.1% of patients in the placebo group were hospitalised or died compared to 7.3% of those on molnupiravir, resulting in a 50% reduction in the risk of hospitalisation or death.
However, the vote by the FDA’s advisory group was closer than originally thought with 13 votes in favour and ten against, reflecting the modest reduction in the risk of hospitalisation and death.
“The efficacy of this product is not overwhelmingly good,” said Los Angeles infectious disease physician and advistory group member, Dr David Hardy, who nonetheless voted in favour due to the need for an oral treatment.
Concerns around side effects were also voiced by advisory body members. “The risk of widespread effects on potential birth defects, especially delayed effects on the male, has not been adequately studied,” said Dr Sankar Swaminathan, an infectious disease specialist at the University of Utah.
The recommendation to the FDA clears the way for a second oral antiviral, Pfizer’s Paxlovid, which is more effective than Merck’s pill.
In fact, Pfizer halted its phase 2/3 trial for the antiviral last month after an analysis showed that it slashed the risk of hospitalisation or death from COVID-19 by nearly 90%.
Paxlovid is a combination of experimental antiviral PF-07321332 and antiretroviral ritonavir, best known as an HIV treatment, which slows the breakdown of PF-07321332 increasing its duration of action.
In the light of the new variant of concern, Omicron, yet to be detected in the USA, the need for treatments for COVID-19 as well as preventative vaccines is climbing. Oral medications like molnupiravir and Paxlovid are significantly more convenient than the injectable COVID-19 treatments that are currently being used, including Gilead’s Veklury (remdesivir).
1st December 2021
