Pharmacokinetics
Conditions
Brief summary
Ritonavir is a potent inhibitor of CYP3A4, one of the enzymes responsible for the metabolism of colchicine. This study will evaluate the effect of multiple doses of ritonavir on the pharmacokinetic profile of a single 0.6 mg dose of colchicine. A secondary objective is to evaluate the safety and tolerability of this regimen in healthy volunteers. All study subjects will be monitored for adverse events throughout the study period.
Detailed description
Ritonavir is a potent inhibitor of CYP3A4, one of the enzymes responsible for the metabolism of colchicine. This study will evaluate the effect of multiple doses of ritonavir on the pharmacokinetic profile of a single 0.6 mg dose of colchicine. A secondary objective is to evaluate the safety and tolerability of this regimen in healthy volunteers. All study subjects will be monitored for adverse events throughout the study period. After a fast of at least 10 hours, twenty-four healthy, non-smoking, non-obese, non-pregnant adult volunteers between the ages of 18 and 45 will be given a single oral dose of colchicine (1 x 0.6 mg tablet) on Day 1. Fasting will continue for 4 hours after the dose. Blood samples will be drawn from all participants before dosing and for twenty-four hours post-dose on a confined basis at times sufficient to adequately define the pharmacokinetics of colchicine. Blood sampling will then continue on a non-confined basis on Days 2-5. After a 14 day washout period, on study Days 15-18, subjects will return to the clinic daily for non-confined dosing of ritonavir (1 x 100 mg capsule) every 12 hours. Administered ritonavir doses on these days will not necessarily be in a fasted state. On Day 15, after taking the first dose of ritonavir, subjects will remain in the clinic for observation for 1 hour post-dose administration. On day 19 after a fast of at least 10 hours, a single dose of colchicine (1 x 0.6 mg tablet) and ritonavir (1 x 100 mg capsule) will be co-administered to all study participants. Fasting will continue for 4 hours following the co-administered doses of ritonavir and colchicine. All participants will be confined to the clinic for dosing and 24-hour blood sampling at times sufficient to adequately determine the pharmacokinetics of colchicine. Blood sampling will continue on a non-confined basis on Days 20-23. The final dose of ritonavir (1 x 100 mg capsule) will be administered to subjects the evening of Day 19, in a non-fasting state. A further goal of this study is to evaluate the safety and tolerability of this regimen in healthy volunteers. Subjects will be monitored throughout participation in the study for adverse reactions to the study drug and/or procedures. Vital signs (blood pressure and pulse) will be measured prior to dosing and at 1, 2, and 3 hours following drug administration on Days 1, 15 and 19 to coincide with peak plasma concentrations of both colchicine and ritonavir. All adverse events whether elicited by query, spontaneously reported, or observed by clinic staff will be evaluated by the Investigator and reported in the subject's case report form.
Interventions
DRUGColchicine
A single dose of colchicine 0.6 mg administered alone at 7:00 a.m. on Day 1 after an overnight fast of at least 10 hours.
DRUGRitonavir
One 100 mg ritonavir capsule administered twice daily at 7:00 a.m. and 7:00 p.m. on Days 15 to 18 without regard to meals, then along with colchicine at 7:00 a.m. on Day 19 after an overnight fast of at least 10 hours; final dose of 100 mg ritonavir administered at 7:00 p.m. on Day 19
Sponsors
Mutual Pharmaceutical Company, Inc.
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy adults 18-45 years of age, non-smoking and non-pregnant (post-menopausal, surgically sterile or using effective contraceptive measures) with a body mass index (BMI) greater than or equal to 18 and less than or equal to 32, inclusive.
Exclusion criteria
* Recent participation (within 28 days) in other research studies * Recent significant blood donation or plasma donation * Pregnant or lactating * Test positive at screening for human immunodeficiency virus (HIV), hepatitis B surface antigen (HbsAg), or hepatitis C virus (HCV) * Recent (2-year) history or evidence of alcoholism or drug abuse * History or presence of significant cardiovascular, hyperlipidemia, pulmonary, hepatic, gallbladder or biliary tract, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic, neurological, or psychiatric disease * Subjects who have used any drugs or substances known to inhibit or induce cytochrome (CYP) P450 enzymes and/or P-glycoprotein (P-gp) within 28 days prior to the first dose and throughout the study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Maximum Plasma Concentration (Cmax) | serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration | The maximum or peak concentration that colchicine reaches in the plasma. |
| Area Under the Concentration Versus Time Curve From Time 0 to Time t [AUC(0-t)] | serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration | The area under the plasma concentration versus time curve, from time 0 to the time of the last measurable colchicine concentration (t), as calculated by the linear trapezoidal rule. |
| Area Under the Concentration Versus Time Curve From Time 0 Extrapolated to Infinity [AUC(0-∞)] | serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration | The area under the plasma concentration versus time curve from time 0 to infinity. AUC(0-∞) was calculated as the sum of AUC(0-t) plus the ratio of the last measurable colchicine plasma concentration to the elimination rate constant. |
Countries
United States
Participant flow
Recruitment details
Twenty-four (24) healthy, non-smoking, male and female volunteers, consisting of members from the community at large, were enrolled in the study.
Pre-assignment details
48 subjects were screened, 11 were screen failures, 7 had schedule conflicts, 6 were not needed
Participants by arm
| Arm | Count |
|---|---|
| Colchicine Alone / With Ritonavir (at Steady-state) \[All subjects received each of the study treatments.\] On Day 1, each subject received one colchicine 0.6 mg tablet at 7:00 a.m. after an overnight fast of at least 10 hours, followed by a washout period of 14 days. On Days 15 to 18, each subject received one 100 mg ritonavir capsule twice daily at 7:00 a.m. and 7:00 p.m. without regards to meals. Then, on Day 19, each subject received both one 0.6 mg colchicine tablet and one 100 mg ritonavir capsule at 7:00 a.m. after an overnight fast. A final dose of ritonavir was administered at 7:00 p.m. that evening. | 24 |
| Total | 24 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Colchicine With Ritonavir | Lost to Follow-up | 1 |
| Ritonavir Alone | liver panel out of range | 6 |
Baseline characteristics
| Characteristic | Colchicine Alone / With Ritonavir (at Steady-state) |
|---|---|
| Age, Categorical <=18 years | 5 Participants |
| Age, Categorical >=65 years | 0 Participants |
| Age, Categorical Between 18 and 65 years | 19 Participants |
| Age Continuous | 23.0 years STANDARD_DEVIATION 4.7 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 24 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 22 Participants |
| Region of Enrollment United States | 24 participants |
| Sex: Female, Male Female | 10 Participants |
| Sex: Female, Male Male | 14 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — |
| other Total, other adverse events | 3 / — | 2 / — | 4 / — |
| serious Total, serious adverse events | 0 / 24 | 0 / 18 | 0 / 18 |
Outcome results
Primary
Area Under the Concentration Versus Time Curve From Time 0 Extrapolated to Infinity [AUC(0-∞)]
The area under the plasma concentration versus time curve from time 0 to infinity. AUC(0-∞) was calculated as the sum of AUC(0-t) plus the ratio of the last measurable colchicine plasma concentration to the elimination rate constant.
Time frame: serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Colchicine Alone | Area Under the Concentration Versus Time Curve From Time 0 Extrapolated to Infinity [AUC(0-∞)] | 10,410.73 pg-hr/mL |
| Colchicine With Ritonavir (at Steady-state) | Area Under the Concentration Versus Time Curve From Time 0 Extrapolated to Infinity [AUC(0-∞)] | 35,276.22 pg-hr/mL |
Primary
Area Under the Concentration Versus Time Curve From Time 0 to Time t [AUC(0-t)]
The area under the plasma concentration versus time curve, from time 0 to the time of the last measurable colchicine concentration (t), as calculated by the linear trapezoidal rule.
Time frame: serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Colchicine Alone | Area Under the Concentration Versus Time Curve From Time 0 to Time t [AUC(0-t)] | 8,412.04 pg-hr/mL |
| Colchicine With Ritonavir (at Steady-state) | Area Under the Concentration Versus Time Curve From Time 0 to Time t [AUC(0-t)] | 29,048.45 pg-hr/mL |
Primary
Maximum Plasma Concentration (Cmax)
The maximum or peak concentration that colchicine reaches in the plasma.
Time frame: serial pharmacokinetic blood samples drawn within 1 hour prior to colchicine dosing (0 hour) on Days 1 and 19, and then 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 12, 24, 36, 48, 72, and 96 hours after colchicine dose administration
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Colchicine Alone | Maximum Plasma Concentration (Cmax) | 1,869.50 pg/mL | Standard Deviation 526.94 |
| Colchicine With Ritonavir (at Steady-state) | Maximum Plasma Concentration (Cmax) | 4,993.06 pg/mL | — |