Coronavirus: What is Merck's molnupiravir pill, how does it work and when will New Zealand get it?

The Opposition is pushing the Government to put in orders for a new pill that's shown early promise at fighting COVID-19. 

National fears New Zealand will end up being behind the rest of the world getting access to molnupiravir, potentially the first oral antiviral medication against the disease that actually works. 

 "That's what other countries we compare ourselves with are doing," Simon Bridges told The AM Show on Friday, referring to molnupiravir and other developing treatments. "They've got those forward orders, some of them have started dishing them out. We should be doing that as well… where's the detailed plan on these sorts of things?" 

The Government says it has been in talks with manufacturer Merck since well before the recent trial results, which suggested it could reduce the chance of hospitalisation in COVID-19 patients by half. 

Here's everything you need to know about molnupiravir.

What is it? 

An antiviral drug originally developed to fight against a pathogen that infects horses, donkeys and zebras, that with some tweaking showed efficacy against various coronaviruses as well as influenza and Ebola.

Named after Thor's hammer Mjölnir, molnupiravir comes in 200mg capsules. Patients take four in the morning and another four in the evening for five days. 

Who makes it? 

Merck - the same company which makes ivermectin, an anti-parasitic which has falsely been touted as a cure for COVID-19 (not by Merck, which has said there is "no scientific basis" for the claims, which have spread through social media amongst anti-vaccination groups). 

It was developed at Emory University in the state of Georgia, using US taxpayer funding, and licenced to Ridgeback Biotherapeutics, which teamed up with pharma giant Merck to develop it. 

The US Government in June said it would buy more than US$1 billion worth of molnupiravir should it work and get approval for use. 

How does it work? 

Molnupiravir works by messing with the virus' ability to replicate itself. It basically tricks the SARS-CoV-2 virus - which causes COVID-19 - into replacing its own cytidine and uridine compounds with those from molnupiravir when it replicates.

"We introduce random mutations into the viral genome, and that is very quickly catastrophic for the virus," said Richard Plemper, antiviral researcher at Georgia State University.

"The result is the accumulation of mutations in the virus RNA which then prevent it from causing illness," said Nial Wheate, associate professor of pharmacology at the University of Sydney. 

In a way, it does what some anti-vaccination activists have falsely claimed of the Pfizer and Moderna vaccines - it messes with genetic code, but only that of the virus, not human cells. 

Being a pill taken orally, molnupiravir has clear advantages over other experimental treatments National has been pushing for - such as ronapreve and sotrovimab, which require infusions or injections. This is not only more expensive, requiring specialist medical equipment and staff, it also risks exposing more people to the virus - whilst molnupiravir can be taken at home, in isolation. 

How did the trial go?

Very well. So well, in fact, the phase III trial was stopped early - the effect was so clear experts determined it would might have been unethical to continue giving half the participants placebos. 

Those who got the pill were 50 percent less likely to end up in hospital than those receiving a placebo. Of the 385 people who got molnupiravir, not a single one died - but eight of the 377 who got placebos lost their lives.

No serious side effects were reported, just a few people reporting mild headaches and diarrhea. 

What concerns have been raised?

Firstly, it has to be taken early. If the disease has already progressed to the point a person needs to be hospitalised, molnupiravir appears to have little effect, an earlier study found.

The phase III trial only involved unvaccinated people - it's not known if it will be as effective at treating breakthrough infections in the vaccinated.

The trial was very short, and so couldn't measure long-term effects - a major concern of those opposed to the COVID-19 vaccines have cited the lack of long-term studies into their effects, so might not be convinced to take molnupiravir either. 

Molnupiravir. Photo credit: Reuters

Because molnupiravir works by introducing mutations, it has the potential to be mutagenic if it gets into the wrong cells, possibly leading to cancer or birth defects. The phase III trial specifically excluded pregnant and breastfeeding women, and all participants were required to either abstain or use highly-effective contraception for the duration of the trial.

A Merck virologist said they've found "no evidence of the potential for mutagenicity" of molnupiravir yet. The company said earlier the drug was "not capable of inducing genetic changes in human cells", Reuters reported. 

When can we expect to see it rolled out? 

Another reason Merck ended the trial early was so it could kickstart the approval process. The European Medicines Agency said earlier this week it’s considering whether to start a "rolling review", essentially reviewing data as it comes in rather than waiting for wider trials to be completed.  

Australia and Singapore aren't waiting, already putting in orders for hundreds of thousands of doses. Other countries including us, the UK and South Korea are in talks with Merck, which is currently seeking emergency authorisation from US authorities. 

"They are going to try to work with alacrity on this," Dean Li, Merck head of research, told Reuters

New Zealand started its vaccine rollout later than many comparable countries, the Government saying this gave us the advantage of seeing whether it was truly as safe and effective as the trials had suggested. Since then we've risen up the world rankings, currently at 35th for first doses and 65th for second, according to the New York Times

Prime Minister Jacinda Ardern earlier this week wouldn't go into detail about where the negotiations with Merck were at "for commercial reasons". No application has been filed with Medsafe yet. 

Merck said it could produce around 10 million courses of molnupiravir by the end of the year. It plans to charge the US government $712 for a course, but hopes to licence the drug to generic manufacturers in India for supply to low- and middle-income countries. 

Should I still get vaccinated? 

Yes. With just two jabs, provided completely free, vaccines significantly reduce the risk of getting infected with negligible chances of any side effects. By getting vaccinated, you also protect others who can't be - such as children. 

"Let's be clear - we should all vaccinate," said Bridges. "We shouldn't be using these other drugs as an excuse not to vaccinate."