Radical cure instrumental in beating malaria

Research findings by Charles Darwin University PhD graduate Dr Robert Commons has the potential to deliver health benefits to millions of malaria sufferers around the globe.

Dr Commons’ research was undertaken in conjunction with the malaria team at Menzies School of Health Research and the global Worldwide Antimalarial Resistance Network.

In 2018, the World Health Organisation estimated there were 228 million cases of malaria worldwide, with 7.5 million of these caused by the malaria species Plasmodium vivax.

Dr Commons’ thesis comprised two systematic reviews and three individual patient-data pooled meta-analyses aimed at optimising current antimalarial drugs for vivax malaria.

It assessed the effect of the drug primaquine co-administration on risk of recurrence and quantified its haematological risks and benefits.

“Effective treatment, known as radical cure, requires a combination of drugs to treat both the blood stage and relapsing liver stage of malaria,” Dr Commons said.

“Some types of malaria can hide in the liver. When someone becomes unwell and is treated for their malaria symptoms, the malaria in the liver might not be killed, which means that it can then emerge from the liver and cause a relapse after a few weeks or months.

“Primaquine is currently the only treatment widely available for the liver stage, however, it can cause the breakdown of red blood cells in vulnerable individuals.”

The thesis highlighted the high risk of recurrence after treatment without primaquine. When administered to patients with normal glucose-6-phosphate dehydrogenase status, primaquine radical cure was safe, effective and reduced anaemia.

It also suggested that in locations where Plasmodium falciparum and Plasmodium vivax strains of malaria co-exist, consideration should be given to extend the use of primaquine to patients presenting with P. falciparum malaria.

“During our research we found that slightly increasing the dose of chloroquine in children could potentially improve initial cure of malaria in 40% more children with vivax malaria. We also found that widespread use of primaquine would prevent up to 90% of the malaria relapses that occur after vivax malaria,” Dr Commons said.

“Interestingly, the COVID-19 pandemic has thrust the spotlight on chloroquine, a drug which has been and is used extensively for malaria; particularly vivax malaria. Much of the safety and dosing data that investigators are using currently to design studies on the use of chloroquine for COVID-19 are based on data from malaria studies.”

Dr Commons, who is an infectious diseases physician based in Ballarat, Victoria, continues to work with the malaria team at Darwin’s Menzies School of Health Research as a senior research officer. He was recently awarded a $566,164 National Health and Medical Research Council Emerging Leader Investigator Grant to continue his research into malaria through Menzies.