Pharmacokinetic (PK) Study of Tafenoquine in Healthy Adults

State University of New York - Upstate Medical University

Status and phase: Begins enrollment this month; Early Phase 1

Conditions: Pharmacokinetic in Normal Population

Treatments: Drug: Tafenoquine Oral Tablet

Study type: Interventional

Funder types: Other

Identifiers

NCT07373743

PR241374 (Other Grant/Funding Number)

2026-01-UMU

Details and patient eligibility

About

The goal of this clinical trial is to learn how people's different genetic makeups affects how their bodies convert the FDA approved drug ARAKODA (tafenoquine) to its active form. Tafenoquine is a drug that is taken to prevent malaria for people traveling to areas where there is malaria. This trial will be in healthy participants age 18-65.

Full description

This trial will explore the how different CYP450 2D6 phenotypes metabolize a single 450mg dose of tafenoquine. Pharmacokinetic (PK) blood and urine samples, and research samples will be obtained at specific timepoints during the 2-month study.

Enrollment: 20 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

1. Age 18-65 at the time of consent, weighing between 132 and 250 pounds
2. Ability and willingness to sign informed consent
3. Available for the study period
4. Willing to use contraception for the duration of the study
5. 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

1. Women: positive urine pregnancy test at screening or day of dosing
2. Women who are lactating or intend to become pregnant during the study period.
3. Acute or chronic clinically significant hematologic, pulmonary, cardiovascular, hepatic, or renal functional abnormality as determined by medical history, physical examination or laboratory screening.
4. History of allergic reaction to tafenoquine or primaquine.
5. 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.
6. Currently taking metformin, dofeltilide or other medication with known multidrug and toxin extrusion enzyme (MATE) metabolism.
7. Known or suspected congenital or acquired immunodeficiency; or receipt of immunomodulation therapy such as anti-cancer chemotherapy or radiation therapy.
8. 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.
9. Participants with hemoglobin, Creatinine, BUN, Albumin, eGFR; ALT, and AST of grade 2 or greater. 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.
10. G6PD result not normal or < 70% activity
11. Significant screening physical examination abnormalities or chronic medical condition that in the opinion of the investigator may impact participant safety, including BMI > 35kg/m2
12. Participation (active or follow-up phase) or planned participation in another vaccine, or drug, in the 4 weeks prior to or during the trial
13. Beliefs that bar the administration of blood products or transfusions
14. Clinician discretion

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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20 participants in 3 patient groups

Normal Metabolizers (NM)

Experimental group

Description:

Participants with normal CYP2D6 enzyme activity receiving a single 450 milligram (mg) dose of tafenoquine.

Treatment:

Drug: Tafenoquine Oral Tablet

Intermediate Metabolizers (IM)

Experimental group

Description:

Participants with decreased activity of the enzyme leading to variable effects i.e., either no effect, increased adverse effects from TQ or reduced efficacy of the drug in endemic areas due to inadequate metabolism receiving a single 450mg dose of tafenoquine.

Treatment:

Drug: Tafenoquine Oral Tablet

Poor Metabolizers (PM)

Experimental group

Description:

Participants with no enzyme activity at all, leading to a null phenotype and no drug metabolism receiving a single 450mg dose of tafenoquine.

Treatment:

Drug: Tafenoquine Oral Tablet