Phenotyping of High Dose Rifampicin (PHENORIF)

The Effect of High Dose Rifampicin on the Activity of Cytochrome P450 Enzymes and P-glycoprotein in Patients With Pulmonary Tuberculosis: a Cocktail Phenotyping Study

Higher doses of rifampicin as a means of more efficient use of this pivotal TB drug has shown promising results and might become standard in future. This means that higher doses of rifampicin will be co-administered with many other drugs taken by TB patients, including anti-retroviral, anti-diabetic, cardiovascular and other drugs. Therefore, in this study the aim is to quantitatively assess the drug interaction potential of high dose rifampicin (~40 mg/kg daily dose, the currently available maximum tolerated dose) with respect to five major human drug-metabolizing CYP enzymes and P-gp in comparison to the conventional dose of 10 mg/kg daily in pulmonary TB patients. A phenotyping approach with single administration of several selective substrates for multiple enzymes will be used, in order to prevent multiple drug-drug interaction studies.

Study Overview

• Status: Completed
• Conditions: Tuberculosis
• Intervention / Treatment: Combination product: phenotyping cocktail; Drug: rifampicin

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 1

Contacts and Locations

Study Locations

• South Africa
  • Cape Town, South Africa
    • TASK
  • Cape Town, South Africa
    • UCT Lung institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 63 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• The participant is able and willing to provide written, informed consent prior to all trial-related procedures.
• The participant is aged between 18 and 65 years, inclusive.
• The participant is a diagnosed pulmonary TB patient.
• The participant is currently being treated with a daily dose of 10 mg/kg rifampicin, i.e. 450 mg daily for patients with a body weight below 55 kg and 600 mg daily for participants with a body weight above 55 kg. This is in correspondence with the local South African TB treatment programme. Furthermore, the participant has to be in the continuation phase of the treatment regimen (i.e. month 3 to 6), has demonstrated reasonable treatment compliance (≥80% of doses) and tolerates treatment well.
• The participant has a body weight (in light clothing and with no shoes) between 40 and 85 kg, inclusive.
• The participant is and stays non-pregnant (based on a negative serum pregnancy test,) and non-lactating (female participants of childbearing potential only).

Exclusion Criteria:

• The patient is in poor general condition where any change in treatment cannot be accepted per discretion of the Investigator.
• The participant has active Hepatitis B.
• The participant has active Hepatitis C.
• The participant is receiving antiretroviral therapy (ART).
• There is evidence showing the participant has clinically significant metabolic, gastrointestinal, or other abnormalities than could possibly alter the PK of rifampicin and/or the probe drugs.
• The participant has a history of or current clinically relevant cardiovascular disorder such as:
• heart failure, atrioventricular (AV) block, arrhythmia, tachyarrhythmia or status after myocardial infarction.
• family history of sudden death of unknown or cardiac-related cause, or of prolonged QTc interval.
• The participant has clinically relevant abnormalities in the ECG such as atrioventricular (AV) block, prolongation of the QRS complex over 100 milliseconds, or of a QTc interval over 450 milliseconds on the screening ECG.
• The participant has abnormal alanine aminotransferase (ALT) and/or aspartate transferase (AST) levels > 3 times the upper limit of the laboratory reference range at screening.
• The participant has a known or suspected, current drug or amphetamine abuse, that is, in the opinion of the Investigator, sufficient to compromise the safety or cooperation of the patient.
• The participant used any drugs or substances known to be strong inhibitors or inducers of cytochrome P450 enzymes and/or P-glycoprotein (P-gp) within 2 weeks prior to day 1 (i.e. 1 month before administration of the phenotyping probes on day 15) of the study (including carbamazepine, barbiturates, St. John's Wort, clarithromycin, itraconazole, fluconazole, quinidine, ketoconazole, erythromycin). Exceptions may be made for participants who have received 3 days or less of one of these drugs or substances, if there has been a wash-out period equivalent to at least 5 half-lives of that drug or substance before day 1 of the study.
• The participant uses any of the phenotyping probe drugs (i.e. midazolam, caffeine, dextromethorphan, tolbutamide, omeprazole and digoxin) as part of standard medical treatment.
• The participant has as history of allergy to any of the phenotyping probe drugs (i.e. midazolam, caffeine, dextromethorphan, tolbutamide, omeprazole and digoxin).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Rifampicin standard dose; rifampicin standard dose + phenotyping cocktail	Combination product: phenotyping cocktail; A single dose of a cocktail of phenotyping probe drugs (caffeine, tolbutamide, omeprazole, dextromethorphan, midazolam and digoxin) will be administered together with standard dose rifampicin and 40 mg/kg rifampicin, respectively. Blood samples will be taken to assess phenotyping metrics of the cocktail agents and rifampicin pharmacokinetic parameters. The effect of high and standard dose rifampicin on the phenotyping metrics of the cocktail agents will be compared by using the bioequivalence approach; Other Names: midazolam; caffeine; omeprazole; digoxin; tolbutamide; dextromethorphan; Drug: rifampicin; A single dose of a cocktail of phenotyping probe drugs (caffeine, tolbutamide, omeprazole, dextromethorphan, midazolam and digoxin) will be administered together with standard dose rifampicin and 40 mg/kg rifampicin, respectively. Blood samples will be taken to assess phenotyping metrics of the cocktail agents and rifampicin pharmacokinetic parameters. The effect of high and standard dose rifampicin on the phenotyping metrics of the cocktail agents will be compared by using the bioequivalence approach
Experimental: Rifampicin high dose; rifampicin high dose + phenotyping cocktail	Combination product: phenotyping cocktail; A single dose of a cocktail of phenotyping probe drugs (caffeine, tolbutamide, omeprazole, dextromethorphan, midazolam and digoxin) will be administered together with standard dose rifampicin and 40 mg/kg rifampicin, respectively. Blood samples will be taken to assess phenotyping metrics of the cocktail agents and rifampicin pharmacokinetic parameters. The effect of high and standard dose rifampicin on the phenotyping metrics of the cocktail agents will be compared by using the bioequivalence approach; Other Names: midazolam; caffeine; omeprazole; digoxin; tolbutamide; dextromethorphan; Drug: rifampicin; A single dose of a cocktail of phenotyping probe drugs (caffeine, tolbutamide, omeprazole, dextromethorphan, midazolam and digoxin) will be administered together with standard dose rifampicin and 40 mg/kg rifampicin, respectively. Blood samples will be taken to assess phenotyping metrics of the cocktail agents and rifampicin pharmacokinetic parameters. The effect of high and standard dose rifampicin on the phenotyping metrics of the cocktail agents will be compared by using the bioequivalence approach

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
area under the curve	area under the curve of probe drugs	24 hours

Collaborators and Investigators

• Sponsor: Radboud University Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): January 7, 2021
• Primary Completion (Actual): August 12, 2021
• Study Completion (Actual): August 12, 2021

Study Registration Dates

• First Submitted: August 20, 2020
• First Submitted That Met QC Criteria: August 20, 2020
• First Posted (Actual): August 25, 2020

Study Record Updates

• Last Update Posted (Actual): August 17, 2021
• Last Update Submitted That Met QC Criteria: August 16, 2021
• Last Verified: August 1, 2021

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Infections; Bacterial Infections; Bacterial Infections and Mycoses; Gram-Positive Bacterial Infections; Actinomycetales Infections; Mycobacterium Infections; Tuberculosis; Hypoglycemic Agents; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Anti-Arrhythmia Agents; Anti-Infective Agents; Central Nervous System Depressants; Nucleic Acid Synthesis Inhibitors; Enzyme Inhibitors; Anesthetics, Intravenous; Anesthetics, General; Anesthetics; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Purinergic Antagonists; Purinergic Agents; Gastrointestinal Agents; Protective Agents; Cardiotonic Agents; Anti-Bacterial Agents; Tranquilizing Agents; Psychotropic Drugs; Hypnotics and Sedatives; Adjuvants, Anesthesia; Anti-Anxiety Agents; GABA Modulators; GABA Agents; Leprostatic Agents; Respiratory System Agents; Cytochrome P-450 Enzyme Inducers; Anti-Ulcer Agents; Proton Pump Inhibitors; Cytochrome P-450 CYP3A Inducers; Antitubercular Agents; Phosphodiesterase Inhibitors; Purinergic P1 Receptor Antagonists; Central Nervous System Stimulants; Antitussive Agents; Antibiotics, Antitubercular; Cytochrome P-450 CYP2B6 Inducers; Cytochrome P-450 CYP2C8 Inducers; Cytochrome P-450 CYP2C19 Inducers; Cytochrome P-450 CYP2C9 Inducers; Digoxin; Midazolam; Dextromethorphan; Rifampin; Caffeine; Omeprazole; Tolbutamide
• Other Study ID Numbers: PHENORIF

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No