Pharmacokinetic (PK) Study of Tafenoquine in Healthy Adults

This trial will explore the how different CYP450 2D6 phenotypes metabolize a single 300mg dose of tafenoquine. Pharmacokinetic (PK) blood and urine samples, and research samples will be obtained at specific timepoints during the 2-month study.

Inclusion criteria

• Age 18-65 at the time of consent, weighing between 132 and 250 pounds
• Ability and willingness to sign informed consent
• Available for the study period
• Willing to use contraception for the duration of the study
• Agree not to take over the counter antioxidants, vitamin C or vitamin E, 2 weeks prior to dosing and 7 days post dosing

Exclusion criteria

• Women: positive urine pregnancy test at screening or day of dosing
• Women who are lactating or intend to become pregnant during the study period.
• Acute or chronic clinically significant hematologic, pulmonary, cardiovascular, hepatic, or renal functional abnormality as determined by medical history, physical examination or laboratory screening.
• History of allergic reaction to tafenoquine or primaquine.
• Scheduled receipt of any vaccine 1 week prior to or after 4 weeks tafenoquine dosing. Routine COVID and influenza vaccination will be allowed outside of this timeframe.
• Currently taking metformin, dofeltilide or other medication with known multidrug and toxin extrusion enzyme (MATE) metabolism.
• Known or suspected congenital or acquired immunodeficiency; or receipt of immunomodulation therapy such as anti-cancer chemotherapy or radiation therapy.
• Diagnosis with Bipolar Disorder or Schizophrenia, hospitalization in the past year for a mental health disorder, or any other psychiatric condition, which in the opinion of the investigator prevents the participant from participating in the study.
• Participants with hemoglobin, Creatinine, BUN, and Albumin of grade 2 or greater. Participants with eGFR <90mL/min/1.73m2; ALT >1.5x ULN, or AST >1.5x ULN. Any exclusionary lab abnormality may be repeated once. If a repeat screening blood test is performed, only the result of the second test will be reviewed and used to determine eligibility.
• Positive HIV, hepatitis B surface antigen or hepatitis C.
• G6PD result not normal or < 70% activity
• Significant screening physical examination abnormalities or chronic medical condition that in the opinion of the investigator may impact participant safety, including BMI > 35kg/m2
• Participation (active or follow-up phase) or planned participation in another vaccine, or drug, in the 4 weeks prior to or during the trial
• Beliefs that bar the administration of blood products or transfusions
• Clinician discretion