GSK’s new malaria drug, Tafenoquine, continues to dominate the malaria word. With international press covering the FDA’s approval of the drug, interest in malaria has increased by 45%.
Tafenoquine is a preventative treatment for relapsing P. vivax malaria, a common strand of the disease. When an individual has relapsing malaria, the malaria parasites remain dormant in their liver, waiting to relapse. GSK’s Tafenoquine, sold under the brand name Krintafel®, aims to remove these parasites from the liver, flushing the body of malaria.
It replaces the current drug, Primaquine, over concerns that it’s recommended ‘one dose every day for fourteen days’ is difficult for patients to comply with, resulting in them not being cured. Tafenoquine, it’s hoped, will offer a single-dose cure for the liver-stage of P. vivax infections, something that the Gates Foundation says is ‘great news’.
Adverse Side Effects
Many have been quick to criticize the FDA’s endorsement of the drug. Tafenoquine is a member of the Quinoline drug family and shares part of its chemical structure with another anti-malaria drug, Mefloquine. Mefloquine is renowned for its neuropsychiatric side effects, resulting in depression, anxiety, nightmares and suicidal ideation. Some of these side effects have been reported to occur after taking Tafenoquine, during clinical trials in the army.
To highlight the adversity of Tafenoquine’s side effects, we’ve been sharing a series of podcast interviews with doctors, professors and veterans to ignite the conversation around the drug’s side effects. These interviews are available by following the link: fightmalaria.uk/Tafenoquine2018
Tafenoquine is developed by GSK and Medicines for Malaria Venture (MMV). According to MMV’s drug profile, the main challenge for Tafenoquine is its required quantitative testing. Before an individual is allowed to take Tafenoquine, they must pass a test which looks for a deficiency in G6PD (Glucose 6-Phosphate Dehydrogenase). The aptly named ‘G6PD test’ evaluates whether an individual may have red blood cells more vulnerable to breaking apart.
When the body cannot replace the destroyed red blood cells, Hemolytic Anemia can develop. This is when a population of red blood cells are removed from the body before their natural lifespan is over. This can result in fatigue, shortness of breath, and potential heart failure. Treatments are available, including blood transfusion and steroid therapy.
Due to the requirement of a G6PD test before Tafenoquine can be administered, some have begun to question how accessible Tafenoquine will be.
According to Professor Jane Quinn, an Australian quinoline researcher, ‘the pre-screening requirements for Tafenoquine can only be done in first world countries’.
This contradicts the rationale for the development of such drugs. With the current test requirements in place, Tafenoquine will be unusable in third world countries, where the burden of P. vivax malaria remains significant. Therefore it’s likely that the drug, in its current form, will be the preserve of military use, administered to soldiers travelling to malaria-endemic regions.