Study finds missed opportunities with COVID antivirals on Australian Pharmaceutical Benefits Scheme

A new study has revealed significant discrepancies in the prescription of COVID-19 antivirals, indicating that many patients may not have received the most effective treatment available.

The retrospective observational study, by researchers from The University of Western Australia and Notre Dame University, analyzed Australian Pharmaceutical Benefits Scheme (PBS) data, and highlighted the need for improved prescription practices to ensure optimal patient outcomes.

The research, published in the journal Infectious Diseases Now, compared the supply of two antiviral treatments, molnupiravir and nirmatrelvir/ritonavir, over the first eight months following their listing on the PBS.

Lead author Dr. Derrick Lopez, Research Fellow at UWA’s School of Population and Global Health, said despite nirmatrelvir/ritonavir being more effective in reducing the risk of severe outcomes from COVID-19, the team found that molnupiravir was prescribed to 73% of patients, while only 27% received nirmatrelvir/ritonavir.

“We found that age was a factor, with older patients less likely to receive nirmatrelvir/ritonavir, with a risk ratio (RR) of 0.50 for those aged 85 plus compared to those under 65,” Dr. Lopez said.

“In all, between 28% and 45% of patients aged 65 and over who received molnupiravir could have been prescribed nirmatrelvir/ritonavir without contraindications, which are circumstances or conditions where the drug shouldn’t have been used.”

Dr. Lopez said while molnupiravir was a crucial early treatment, the findings suggested that many patients might have benefited more from nirmatrelvir/ritonavir and called for investment in quality improvement systems to enhance the efficacy and safety of COVID-19 treatments.

“Ensuring that the most effective drugs are prescribed when there are no contraindications could significantly improve patient outcomes and reduce hospitalizations and deaths,” he said.