Drug Interaction Study

Study to Evaluate the Exposure of Rifabutin Administered in an Alternate Regimen in Combination With Atazanavir and Ritonavir Healthy Subjects

The purpose of this study is to evaluate the exposure of rifabutin (RIB) when administered with atazanavir and ritonavir (ATV/RTV)

Study Overview

• Status: Completed
• Conditions: Antivirals/HIV
• Intervention / Treatment: Drug: Rifabutin; Drug: Rifabutin + Atazanavir + Ritonavir

• Study Type: Interventional
• Enrollment (Actual): 85
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • New Jersey
    • Hamilton, New Jersey, United States, 08690
      • Bristol-Myers Squibb Clinical Pharmacology Unit

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy male and female subjects between the ages of 18 to 50 years old with a body mass index (BMI) of 18 to 32 kg/m²
• Prior to enrollment, subjects must have physical and laboratory test findings within the normal limits, and women of childbearing potential (WOCBP) must have a negative pregnancy test

Exclusion Criteria:

• Any significant acute or chronic medical illness
• Evidence of organ dysfunction or any clinically significant deviation from normal in physical examination, vital signs, electrocardiogram (ECG) or clinical laboratory determinations
• Use of any prescription drugs or over-the-counter acid controllers within 4 weeks prior to study drug administration
• Use of any other drugs, including over-the-counter medications of herbal preparations within 1 week prior to study drug administration

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: A	Drug: Rifabutin; Capsule, Oral, 150 mg, once daily, 11 Days
Active Comparator: B	Drug: Rifabutin + Atazanavir + Ritonavir; Capsules, Oral, 18 Days Rifabutin (150 mg, 2x/wk) Atazanavir (300 mg, once daily) Ritonavir (100 mg, once daily); Other Names: Reyataz

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average Area Under the Plasma Concentration-time Curve for 24 Hours (AUC24avg) for Rifabutin (RIB)	AUC24avg is AUC(0-24 hour) following dosing on Day 10 for RIB 150mg once daily (QD); AUC24avg is the area under the plasma concentration-time curve in 1 dosing interval (AUC[TAU]) divided by the number of days over the sampling duration for ATV/RTV 300/100 mg QD+RIB 150 mg twice weekly, i.e. AUC(TAU)/7.	Pre-dose (0 hours [h]) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Maximum Plasma Concentration (Cmax) of RIB	Cmax was derived from plasma concentration versus time for RIB and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Minimum Plasma Concentration (Cmin) of RIB	Cmin was derived from plasma concentration versus time for RIB.	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
AUC24avg for 25-O-Desacetyl-RIB	AUC24avg is AUC(0-24 hour) following dosing on Day 10 for RIB 150 mg QD; AUC24avg is the area under the plasma concentration-time curve in 1 dosing interval (AUC[TAU]) divided by the number of days over the sampling duration for ATV/RTV 300/100 mg QD+RIB 150 mg twice weekly, i.e. AUC(TAU)/7	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Cmax of 25-O-Desacetylrifabutin (25-O-Desacetyl-RIB)	Cmax was derived from the plasma concentration versus time for 25-O-Desacetyl-RIB (a metabolite of RIB) and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Cmin of 25-O-Desacetyl-RIB	Cmin was derived from plasma concentration versus time for 25-O-Desacetyl-RIB.	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Total Area Under the Plasma Concentration-time Curve (AUCtot)	AUCtot represents the total free RIB plus 25-O-Desacetyl-RIB output. It is calculated as: AUCtot (micromolar[µM]*h) = AUC24avg(RIB)(ng*h/mL)/847.016 (g/mole) + AUC24avg(25-O-Desacetyl-RIB)(ng*h/mL)/804.979(g/mole). The 300 mg RIB arm represents an extrapolation from the 150 mg RIB group.	Pre-dose (0h) on Days 6, 8, 10, and 11, and post-dose (1h,2h,3h,4h,6h,8h,12h) on Day 10 for RIB 150 mg QD; and pre-dose (0h) on Days 4, 8,11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cmax of ATV	Cmax was derived from the plasma concentration versus time for ATV and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Cmin of ATV	Cmin was derived from the plasma concentration versus time for ATV.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
AUC(TAU) for ATV	AUC(TAU) was derived from the plasma concentration versus time for ATV, and was calculated by linear and log-linear trapezoidal summations using a mixed log-linear algorithm.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Time to Reach Maximum Observed Plasma Concentration (Tmax) of ATV	Tmax was derived from the plasma concentration versus time for ATV and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Terminal Elimination Half-life (T-half) of ATV	T-half was obtained directly from the concentration-time data. T-half following doses administered for treatment ATV/RTV 300/100 mg QD+RIB 150 mg twice weekly.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Cmax of RTV	Cmax was derived from the plasma concentration versus time for RTV and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Cmin of RTV	Cmin was derived from the plasma concentration versus time for RTV.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
AUC(TAU) for RTV	AUC(TAU) was derived from the plasma concentration versus time for RTV, and was calculated by linear and log-linear trapezoidal summations using a mixed log-linear algorithm.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Tmax of RTV	Tmax was derived from the plasma concentration versus time for RTV and was recorded directly from experimental observations for each treatment period.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
T-half of RTV	T-half was obtained directly from the concentration-time data.	Pre-dose (0h) on Days 4, 8, 11 to 18 and post-dose (1h,2h,3h,4h,6h,8h,12h) on Days 11 and 15 for ATV/RTV + RIB.
Number of Participants Who Died, Experienced Other Serious Adverse Events (SAEs), Experienced Adverse Events (AEs) and Experienced Events Leading to Discontinuation.	AEs were defined as new, untoward medical occurrences/worsening of pre-existing medical condition, whether drug-related or not. SAEs were defined as any AE that: resulted in death; was life threatening; resulted in a persistent or significant disability/incapacity; resulted in/prolonged an existing in-patient hospitalization; was a congenital anomaly/birth defect; was a cancer; or was an overdose. Discontinuation from the study was due either to an AE or was conducted at the investigator's discretion.	From Day 1 to 30 days after the last dose of study drug.
Number of Participants With Marked Abnormalities (MAs) in Hematology: Hemoglobin, Hematocrit, Platelet Count and Leukocytes	MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Hemoglobin/hematocrit: <0.85 x pre-treatment (pre-Rx) value. Platelet count: <0.85 x lower limit of normal (LLN) (or, if pre-Rx value <LLN, then <0.85 x pre-Rx value) or >1.5 x upper limit of normal (ULN). Leukocytes: <0.9 x LLN or >1.2 x ULN (or, if pre-Rx value <LLN, then <0.85 x pre-Rx or >ULN. If pre-Rx value >ULN, then >1.15 x pre-Rx or <LLN).	Pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14, 20 and 26 for RIB 150 mg QD; and pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14 and 18 for ATV/RTV 300/100 mg QD + RIB 150 mg twice weekly.
Number of Participants With MAs in Hematology: Neutrophils + Bands (Absolute), Lymphocytes (Absolute), Monocytes (Absolute), Basophils (Absolute) and Eosinophils (Absolute)	MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following hematology MA definitions specify the criteria for the data presented. Neutrophils+bands (absolute): <=1.50 x 10^3 cells/microliter (uL). Lymphocytes (absolute): <0.75 x 10^3 cells/uL or >7.50 x 10^3 cells/uL. Monocytes (absolute): >2.00 x 10^3 cells/uL. Basophils (absolute): >0.40 x 10^3 cells/uL. Eosinophils (absolute): >0.75 x 10^3 cells/uL.	Pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14, 20 and 26 for RIB 150 mg QD; and pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14 and 18 for ATV/RTV 300/100 mg QD + RIB 150 mg twice weekly.
Number of Participants With MAs in Serum Chemistry: Alkaline Phosphatase (ALP),Aspartate Aminotransferase (AST),Alanine Aminotransferase (ALT),Bilirubin (Total),Bilirubin (Direct),Blood Urea Nitrogen (BUN),Creatinine,Sodium (Serum),Potassium (Serum)	MAs=laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria. ALP, AST, ALT:>1.25xULN (if pre-Rx >ULN, then >1.25xpre-Rx). Bilirubin (total), bilirubin (direct), BUN:>1.1xULN (if pre-Rx >ULN, then >1.25xpre-Rx). Creatinine:>1.33xpre-Rx. Sodium (serum):<0.95xLLN or >1.05xULN (if pre-Rx <LLN, then <0.95xpre-Rx or >ULN. If pre-Rx >ULN, then >1.05xpre-Rx or <LLN). Potassium (serum):<0.9xLLN or >1.1xULN (if pre-Rx <LLN, then <0.9xpre-Rx or >ULN. If pre-Rx >ULN, then >1.1xpre-Rx or <LLN).	Pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14, 20 and 26 for RIB 150 mg QD; and pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14 and 18 for ATV/RTV 300/100 mg QD + RIB 150 mg twice weekly.
Number of Participants With MAs in Serum Chemistry: Chloride (Serum), Calcium (Total), Protein (Total), Bicarbonate, Phosphorous (Inorganic)	MAs=laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria. Chloride (serum), calcium (total), protein (total):<0.9xLLN or >1.1xULN (if pre-Rx <LLN, then <0.9xpre-Rx or >ULN. If pre-Rx >ULN, then >1.1xpre-Rx or <LLN). Bicarbonate:<0.8xLLN or >1.2xULN (if pre-Rx value <LLN, then <0.8xpre-Rx value or >ULN. If pre-Rx >ULN, then >1.2xpre-Rx value or <ULN). Phosphorous (inorganic):<0.85xLLN or >1.25xULN (if pre-Rx <ULN, then <0.85xpre-Rx or <ULN. If pre-Rx >ULN, then >1.25x re-Rx or <LLN).	Pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14, 20 and 26 for RIB 150 mg QD; and pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14 and 18 for ATV/RTV 300/100 mg QD + RIB 150 mg twice weekly.
Number of Participants With MAs in Serum Chemistry: Glucose (Fasting Serum), Albumin, Creatine Kinase, Uric Acid, Lactate Dehydrogenase (LDH)	MAs=laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following serum chemistry MA definitions specify MA criteria. Glucose (fasting serum): <0.8 x LLN or >1.5 ULN (if pre-Rx <LLN, then <0.8 x pre-Rx or >ULN. If pre-Rx >ULN, then >2.0 x pre-Rx or <LLN. Albumin: <0.9 x LLN (if pre-Rx <LLN, then <0.9 x pre-Rx). Creatine kinase: >1.5 x ULN (if pre-Rx >ULN, then >1.5 x pre-Rx). Uric acid: >1.2 x ULN (if pre-Rx >ULN, then >1.25 x pre-Rx). LDH: >1.25 x ULN (if pre-Rx >ULN, then >1.5 x pre-Rx).	Pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14, 20 and 26 for RIB 150 mg QD; and pre-dose on Day -1 and post-dose on Days 3, 7, 11, 14 and 18 for ATV/RTV 300/100 mg QD + RIB 150 mg twice weekly.
Number of Participants With MAs in Urinalysis	MAs are laboratory measurements marked as abnormal, per pre-defined study criteria, at any study time point. The following definitions specify the criteria for MAs. Protein, glucose and blood: >=2+ (or, if pre-treatment value >=1+, then >= 2 x pre-treatment value).	Pre-dose on Day -1, Day 7 and discharge.
Number of Participants With Identified Electrocardiogram (ECG) Abnormalities	ECG abnormalities were defined as findings that are clinically meaningful as judged by the investigator. A 12-lead ECG was recorded at least 5 minutes after the participant had been lying down and all ECG recordings were evaluated by the investigator. Abnormalities, if present at any study time point, were listed.	Pre-dose on Day -1 and study discharge.
Number of Participants With Clinically Significant Vital Signs or Physical Examination Findings	Vital signs assessments and physical examination were conducted throughout the study. Vital signs assessments included body temperature, respiratory rate, blood pressure (systolic and diastolic), and heart rate. Physical examination included a neurological examination (if ocular signs or symptoms occurred, a reflex to slit lamp exam was performed by an ophthalmologist). The investigator used his/her clinical judgment to decide whether or not abnormalities in vital signs or physical examination were clinically meaningful.	Vital signs:screening, prior to dosing on Day 1, Day 7, study discharge. Physical examination:screening, Day -1, Day 7, study discharge

Collaborators and Investigators

• Sponsor: Bristol-Myers Squibb

Publications and helpful links

General Publications

• Zhang J, Zhu L, Stonier M, Coumbis J, Xu X, Wu Y, Arikan D, Farajallah A, Bertz R. Determination of rifabutin dosing regimen when administered in combination with ritonavir-boosted atazanavir. J Antimicrob Chemother. 2011 Sep;66(9):2075-82. doi: 10.1093/jac/dkr266. Epub 2011 Jun 28.

Study record dates

Study Major Dates

• Study Start: April 1, 2008
• Primary Completion (Actual): August 1, 2008
• Study Completion (Actual): August 1, 2008

Study Registration Dates

• First Submitted: March 26, 2008
• First Submitted That Met QC Criteria: March 26, 2008
• First Posted (Estimate): March 31, 2008

Study Record Updates

• Last Update Posted (Estimate): January 31, 2013
• Last Update Submitted That Met QC Criteria: January 23, 2013
• Last Verified: January 1, 2013

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Molecular Mechanisms of Pharmacological Action; Anti-Infective Agents; Antiviral Agents; Enzyme Inhibitors; Anti-HIV Agents; Anti-Retroviral Agents; Protease Inhibitors; Anti-Bacterial Agents; Cytochrome P-450 CYP3A Inhibitors; Cytochrome P-450 Enzyme Inhibitors; HIV Protease Inhibitors; Viral Protease Inhibitors; Antitubercular Agents; Antibiotics, Antitubercular; Ritonavir; Rifabutin; Atazanavir Sulfate
• Other Study ID Numbers: AI424-360