Molnupiravir ‘effective Covid antiviral’: acting CMO Michael Kidd

Michael Kidd has contradicted the nation’s top advisers on Covid-19 treatments on the efficacy of Australia’s most widely prescribed antiviral medication.

Covid-19 antiviral drug Molnupiravir

Acting chief medical officer Michael Kidd has contradicted the nation’s top advisers on Covid-19 treatments on the efficacy of Australia’s most widely prescribed antiviral medication, molnupiravir, insisting it is highly effective for older Australians.

The National Clinical Evidence Taskforce on Friday issued new guidance on molnupiravir having determined, based on a large UK clinical trial, that there was “high certainty evidence that molnupiravir does not have an impact on the combined endpoint of hospitalisation and/or mortality in multiply-vaccinated adults with mild Covid-19 and one or more risk factors for disease progression”.

The Taskforce made a conditional recommendation that clinicians “should not routinely use molnupiravir for the treatment of Covid-19”. Paxlovid has been repeatedly shown to have a much higher efficacy than molnupiravir, but it is unsuitable for many patients because of the way it interacts with a host of other drugs.

The Taskforce is made up of 35-member organisations including all of Australia’s top medical colleges and undertakes rigorous evidence surveillance and evaluation.

Professor Kidd issued a statement following the new guidance insisting molnupiravir, which is sold as Lagevrio, together with Paxlovid had been a “gamechanger” in the treatment of Covid-19.

“Australia’s real-world experience is that the two Covid-19 oral antiviral treatments approved for local use are both highly effective at protecting older Australians – a key at-risk population group – from hospitalisation and death,” he said in the statement.

“The real-world findings are based on an analysis of Victorian data involving more than 27,000 people aged 70 years and over. This analysis found that the use of Covid-19 oral antivirals led to clear reductions in the risks of hospitalisation and death, compared to instances where treatments were not used. Given people aged 70 and over are eligible for the treatments in every state and territory, the conclusions are applicable nationwide.”

The Victorian research has not been published nor peer reviewed.

The reason Dr Kidd gave for discounting the UK PANORAMIC trial findings relied upon by the Taskforce were that the 26,000 participants in that study were generally younger than those eligible for treatments in Australia and many had no risk factors that would make them more likely to become seriously unwell.

“A large proportion of the people enrolled in the UK study would not be eligible for the treatments in Australia and these research findings cannot be directly applied to most people receiving treatments in Australia,” Dr Kidd said.

“Australia’s Pharmaceutical Benefits Advisory Committee (PBAC) recently noted that in two-thirds of the instances in which molnupiravir had been used through its listing on the Pharmaceutical Benefits Scheme, patients were aged 70 years or over. In the PANORAMIC study, only 6 per cent of participants were aged 75 years or older.

“PBAC also noted patients at highest risk of progression to severe disease in the UK were not the target population for enrolment in the PANORAMIC trial. In Australia, these are the people who have specifically been made eligible for these treatments.

“It further noted the Victorian data, combined with the results of observational studies in Israel and Hong Kong, demonstrated a benefit of molnupiravir over no treatment in patients at high risk of progression to severe disease.

“PBAC concluded that while nirmatrelvir and ritonavir may be preferred for many patients at high risk of becoming severely unwell, in many common clinical circumstances, this treatment is contraindicated or unsuitable for use, especially in people with some underlying conditions, such as severe kidney or liver disease. It also has a number of drug interactions with commonly used medicines.

In such circumstances, molnupiravir remains a suitable option.”

Dr Kidd urged older Australians diagnosed with Covid to continue to discuss antiviral treatments including molnupiravir with urgency with their doctors.