GPs could soon have an antiviral pill to treat COVID-19

The results of US-based clinical trials could herald the arrival of more accessible treatments for COVID-19.
 
The US-based pharmaceutical company Merck – known domestically as MSD Australia – released results last Friday which indicate molnupiravir, an oral antiviral drug, significantly reduces the risk of severe illness.
 
An interim analysis of a phase 3 trial, carried out on patients with at least one underlying risk factor for poor outcomes from the disease, suggests the drug reduced the chances of hospitalisation by around 50%.
 
The company reports that 28 patients out of 385 (7.3%) needed hospital treatment by day 29 after diagnosis, compared to 14.1% of those treated with a placebo. There were also no deaths reported in patients who received molnupiravir, while eight died in the placebo group.
 
Peter White, a professor of microbiology at UNSW, told newsGP the results are very encouraging.
 
‘It’s very exciting, I have been waiting for this since day one,’ he said. ‘This is excellent news.
 
‘Vaccines are the best – prevention is always better than cure – but the other weapon we have got are antivirals.
 
‘What they will do is cut the symptoms down. It won’t cure them immediately but it will reduce the severity of the illness.’
 
Professor White also said that while the treatment has lagged behind the development of vaccines, the evolution of antiviral drugs has still happened swiftly.
 
‘Vaccines are easier to make than antivirals,’ he said. ‘If we look at Hepatitis C, it took about 10 years to really get good antivirals.

‘This is quick – we’re only a couple of years into the pandemic and we’ve already got one.’
 
The molnupiravir treatment is being developed with a Miami-based biotech company Ridgeback Biotherapeutics and is designed to inhibit the virus from multiplying by introducing errors into its genetic code.
 
All of the patients in the clinical trial were confirmed cases of COVID-19 with symptoms beginning within five days of the study’s randomisation.  
 
A spokesperson for the company said the treatment reduced risks ‘across all key subgroups’ and that the drug’s efficacy was unaffected by underlying risk factors.
 
The announcement last week also said the treatment demonstrated ‘consistent efficacy’ against different variants of the virus, including Gamma, Delta and Mu.
 
Professor White said the drug is likely to be among several oral antiviral treatments for COVID-19 that will become available.
 
‘This is going to be the first of a number of drugs that will target the actual viral enzyme,’ he said.
 
‘I would expect in another couple of years, there will be maybe 20 of these drugs and they will make a difference.’
 
If approved for use in Australia, Professor White said it is ‘absolutely’ possible that GPs will be able to prescribe drugs such as molnupiravir as part of treatment for patients with COVID-19.
 
He also said antivirals could be used as a prophylactic if there is an outbreak on a cruise ship, for example.
 
Merck plans to apply to the US Food and Drug Administration (FDA) for emergency use authorisation for molnupiravir ‘as soon as possible’ as a result of the clinical trials. It has also signalled its intent to make applications to other regulatory bodies around the world, including in Australia.
 
In August, the Therapeutic Goods Administration (TGA) gave the green light for MSD Australia to apply for provisional registration for the treatment.
 
An MSD Australia spokesperson told newsGP the company has had ‘productive discussions’ with the Federal Government about molnupiravir and that it is ‘committed to making this treatment option available should it be registered by the TGA’.
 
Other clinical trials of antiviral pills designed to treat COVID-19, developed by Pfizer along with a number of other pharmaceutical companies, are also taking place.
 
Two antiviral treatments have already been approved for use in Australia, although no oral treatment is among them so far.
 
The TGA approved remdesivir for use last year. The use of sotrovimab, a novel monoclonal antibody treatment, was approved by the TGA in August. Both are administered intravenously.
 
Studies suggest sotrovimab reduces the risk of hospitalisation or death by 79% in adults more likely to develop severe COVID-19. These include those over 55 years old with at least one comorbidity such as diabetes, obesity, chronic kidney disease, heart failure, lung disease or moderate to severe asthma.
 
But while studies suggest greater overall efficacy from the intravenous sotrovimab treatment, there are concerns over its accessibility, particularly in more remote areas.
 
On Monday, the Government announced it had increased an initial order of sotrovimab for the National Medical Stockpile from 7700 doses to more than 31,000, with the arrival of additional stocks due over the next few months.

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antiviral treatments COVID-19 Merck molnupiravir Pfizer