Tafenoquine Pharmacokinetics Study

This trial aims to understand how genetic differences affect the body's processing of tafenoquine, a drug used to prevent malaria. Researchers are particularly interested in how individuals with varying enzyme activities respond to a single dose. Participants will be grouped based on whether their bodies process the drug normally, slowly, or not at all. Ideal candidates for this trial are healthy individuals weighing between 132 and 250 pounds and not currently taking certain medications, such as metformin. As an Early Phase 1 trial, this research focuses on understanding tafenoquine's effects in people, offering participants the opportunity to contribute to foundational knowledge about the drug.

The trial requires that you do not take over-the-counter antioxidants, vitamin C, or vitamin E starting two weeks before and until seven days after dosing. If you are currently taking metformin, dofeltilide, or other medications with known MATE metabolism, you cannot participate in the trial.

Research shows that tafenoquine, a drug approved by the FDA to prevent malaria, is generally safe and well-understood. Previous studies have found that most people tolerate tafenoquine well, although some may experience side effects like vomiting. Not everyone experiences these side effects, but awareness is important.

Genetics influence how people's bodies handle tafenoquine. Some might experience more side effects, or the drug might not work as effectively for them. Studies have shown that the breakdown of the drug varies among individuals, affecting their response.

Unlike the standard of care for malaria, which often involves drugs like chloroquine or artemisinin-based combination therapies, tafenoquine offers a novel approach by utilizing a single-dose regimen. This treatment is unique because it targets the dormant liver stages of the parasite, potentially preventing relapses with just one dose. Researchers are excited about tafenoquine because it could simplify treatment protocols and improve patient adherence, especially in regions where malaria is endemic. Additionally, understanding the drug's effectiveness across different metabolizer types can lead to more personalized and effective malaria treatments.

Research has shown that tafenoquine effectively prevents malaria. Studies indicate it works 84 to 87% of the time against falciparum malaria and 99.1% against vivax malaria. In individuals with normal levels of the enzyme G6PD, the drug prevented malaria recurrence in 88.6% of cases for at least 90 days. This trial will examine tafenoquine in different metabolizer groups: Normal Metabolizers (NM), Intermediate Metabolizers (IM), and Poor Metabolizers (PM), each receiving a single 450 mg dose. Most people tolerate the drug well, though some may experience mild stomach issues.⁶⁷⁸⁹¹⁰