Trial Outcomes & Findings for Tariquidar-ondansetron Combination in Neuropathic Pain (NCT NCT04603066)
NCT ID: NCT04603066
Last Updated: 2025-08-14
Results Overview
AUCinf for Ondansetron concentration in plasma based on venous blood sampling for plasma concentrations of ondansetron obtained at 0, 15, 30, 60, 90, 120, 180, and 240 minutes from the beginning of ondansetron infusion.
COMPLETED
PHASE1/PHASE2
24 participants
Measurements over 240 minutes, extrapolated to infinity
2025-08-14
Participant Flow
Participant milestones
| Measure |
Ondansetron/Placebo First, Then Ondasetron/Tariquidar
The study group where patients received Ondansetron with Placebo during Visit 1, and after a washout period of 3 weeks Ondansetron with Tariquidar at Visit 2 per the randomization schedule.
Ondansetron 16 mg was administered IV over 60 minutes with placebo (D5W) or with tariquidar (4mg/kg dose in D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
Ondansetron/Tariquidar First, Then Ondansetron/Placebo
The study group where patients received Ondansetron with Tariquidar during Visit 1, and after 3 weeks of washout period Ondansetron with Placebo at Visit 2 per the randomization schedule.
Ondansetron 16 mg was administered IV over 60 minutes with tariquidar (4mg/kg dose in D5W) or with placebo (D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
|---|---|---|
|
Visit 1
STARTED
|
12
|
12
|
|
Visit 1
COMPLETED
|
12
|
12
|
|
Visit 1
NOT COMPLETED
|
0
|
0
|
|
Wash-out (3 Weeks)
STARTED
|
12
|
12
|
|
Wash-out (3 Weeks)
COMPLETED
|
11
|
12
|
|
Wash-out (3 Weeks)
NOT COMPLETED
|
1
|
0
|
|
Visit 2
STARTED
|
11
|
12
|
|
Visit 2
COMPLETED
|
11
|
12
|
|
Visit 2
NOT COMPLETED
|
0
|
0
|
Reasons for withdrawal
| Measure |
Ondansetron/Placebo First, Then Ondasetron/Tariquidar
The study group where patients received Ondansetron with Placebo during Visit 1, and after a washout period of 3 weeks Ondansetron with Tariquidar at Visit 2 per the randomization schedule.
Ondansetron 16 mg was administered IV over 60 minutes with placebo (D5W) or with tariquidar (4mg/kg dose in D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
Ondansetron/Tariquidar First, Then Ondansetron/Placebo
The study group where patients received Ondansetron with Tariquidar during Visit 1, and after 3 weeks of washout period Ondansetron with Placebo at Visit 2 per the randomization schedule.
Ondansetron 16 mg was administered IV over 60 minutes with tariquidar (4mg/kg dose in D5W) or with placebo (D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
|---|---|---|
|
Wash-out (3 Weeks)
Protocol Violation
|
1
|
0
|
Baseline Characteristics
Tariquidar-ondansetron Combination in Neuropathic Pain
Baseline characteristics by cohort
| Measure |
Ondansetron With Tariquidar First, Then Ondansetron With Placebo
n=12 Participants
The study group where patients received Ondansetron with Tariquidar during Visit 1, and Ondansetron with Placebo at Visit 2 per the randomization schedule. The washout period between two visits was 3 weeks.
Ondansetron 16 mg was administered IV over 60 minutes with tariquidar (4mg/kg dose in D5W) or with placebo (D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
Ondansetron With Placebo First, Then Ondansetron With Tariquidar
n=12 Participants
The study group where patients received Ondansetron with Placebo during Visit 1, and Ondansetron with Tariquidar at Visit 2 per the randomization schedule. The washout period between two visits was 3 weeks.
Ondansetron 16 mg was administered IV over 60 minutes with placebo (D5W) or with tariquidar (4mg/kg dose in D5W). Ondansetron was diluted in 100mL 0.9% normal saline, and tariquidar was diluted in 500mL D5W.
|
Total
n=24 Participants
Total of all reporting groups
|
|---|---|---|---|
|
Age, Continuous
|
52.5 years
STANDARD_DEVIATION 12.87 • n=5 Participants
|
49.33 years
STANDARD_DEVIATION 12.16 • n=7 Participants
|
50.92 years
STANDARD_DEVIATION 12.35 • n=5 Participants
|
|
Sex: Female, Male
Female
|
8 Participants
n=5 Participants
|
8 Participants
n=7 Participants
|
16 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
4 Participants
n=5 Participants
|
4 Participants
n=7 Participants
|
8 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Hispanic or Latino
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Not Hispanic or Latino
|
12 Participants
n=5 Participants
|
12 Participants
n=7 Participants
|
24 Participants
n=5 Participants
|
|
Ethnicity (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Asian
|
1 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
1 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
White
|
11 Participants
n=5 Participants
|
12 Participants
n=7 Participants
|
23 Participants
n=5 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
0 Participants
n=5 Participants
|
0 Participants
n=7 Participants
|
0 Participants
n=5 Participants
|
PRIMARY outcome
Timeframe: Measurements over 240 minutes, extrapolated to infinityPopulation: participants who completed both sessions
AUCinf for Ondansetron concentration in plasma based on venous blood sampling for plasma concentrations of ondansetron obtained at 0, 15, 30, 60, 90, 120, 180, and 240 minutes from the beginning of ondansetron infusion.
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=22 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=22 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Concertation-time Profile of Ondansetron in Plasma, Measured by the Area Under the Concentration-time Curve (AUC)
|
0.89 mg*hr/L
Standard Deviation 0.29
|
0.87 mg*hr/L
Standard Deviation 0.45
|
PRIMARY outcome
Timeframe: anytime between 0-240 minutesPopulation: Participant who had both CSF and plasma samples drawn at the same time, at both sessions.
The level of ondansetron in plasma and CSF (cerebrospinal fluid) in samples, taken around the same time, was measured, and the ratio of the two values was calculated. This ratio (partition coefficient, Kp) of ondansetron, compared between the two sessions, with placebo vs tariquidar
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=7 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=7 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Cerebrospinal Fluid to Plasma Concentration Ratio of Ondansetron
|
0.132 ratio
Standard Error 0.017
|
0.112 ratio
Standard Error 0.018
|
SECONDARY outcome
Timeframe: baseline to 90 minutes after ondansetron IV infusionPopulation: All patients who received both treatments, excluding pharmacokinetic outlier (patient N 06)
Change in spontaneous pain intensity (measured on a 0-10 numerical rating scale; 0=no pain, 10=worst imaginable pain) from baseline to 90 minutes after ondansetron IV infusion, compared between two sessions with and without tariquidar. Values are presented as a percentage change from baseline.
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=22 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=22 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
% Change in Pain Intensity
|
37.2 % change from baseline
Standard Deviation 35.1
|
28.8 % change from baseline
Standard Deviation 28.7
|
SECONDARY outcome
Timeframe: Baseline and 90 minutes after the end of ondansetron infusionPopulation: All patients who completed both CPM procedures
Conditioned Pain Modulation (CPM) is a psychophysical test to assess the efficiency of descending pain inhibition. CPM is calculated as difference in heat pain threshold with and without pain conditioning - i.e. immersion of a hand in cold water. Conditioned Pain Modulation (CPM) Negative CPM values represent efficient pain modulation/inhibition. This test was administered at baseline, and again 90-min after the end of ondansetron infusion. CPM values can range from -100 to 100, CPM\<0 (i.e. decreased pain to heat stimulus following conditioning) implies descending pain inhibition. CPM Magnitude (ΔCPM) is the calculated by subtracting the measurement of CPM at baseline \[possible range of CPM scores 0-100\] from the measurement of CPM 90 min after the intervention \[possible range of CPM scores 0-100\]. A larger negative ΔCPM value indicates increased pain modulation efficiency following treatment, and therefore, a desired outcome.
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=20 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=20 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Conditioned Pain Modulation (CPM) Magnitude (ΔCPM)
|
0.1 score on a scale of 0-100
Standard Error 8.2
|
1.8 score on a scale of 0-100
Standard Error 10.4
|
SECONDARY outcome
Timeframe: 0-240 min from infusionPopulation: All patients who completed CPM and reported spontaneous pain intensity at corresponding time points
The association between baseline Conditioned Pain Modulation (CPM) magnitude (ΔCPM) and the % pain reduction from baseline will be determined by bivariate regression.
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=20 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=20 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Correlation Between CPM Magnitude (ΔCPM) and Change in Pain Intensity
|
0.02 r2
|
0.01 r2
|
SECONDARY outcome
Timeframe: baseline to 70 min after infusionChanges in the Neuropathic Pain Symptom Inventory (NPSI) total score will be compared between treatment sessions. NPSI is a questionnaire used to assess and quantify neuropathic pain by asking patients to rate the severity of different pain sensations on a scale of 0 to 10, with 0 being no pain and 10 being the worst pain imaginable. The version administered in the study consists of seven questions, each rated on a scale from 0 to 10, with the total score being the sum of all ratings. The possible range of the NPSI score of the version administered in the study is 70, and, since we measure the difference in scores, the changes in the NPSI score of the version administered in the study is -70 to 70. Higher NPSI scores indicate more severe neuropathic pain symptoms. Since the analysis is conducted on changes in NPSI scores from baseline, a more negative value corresponds to a greater reduction in neuropathic pain symptoms following treatment.
Outcome measures
| Measure |
Ondansetron + Tariquidar
n=22 Participants
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=22 Participants
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Change in Neuropathic Pain Symptom Inventory (NPSI) Score
|
-8.6 units on a scale
Standard Error 7.0
|
-13.2 units on a scale
Standard Error 7.1
|
Adverse Events
Ondansetron + Tariquidar
Ondansetron + Placebo
Serious adverse events
Adverse event data not reported
Other adverse events
| Measure |
Ondansetron + Tariquidar
n=23 participants at risk
Ondansetron 16 mg with Tariquidar: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
Ondansetron + Placebo
n=24 participants at risk
Ondansetron 16 mg with Placebo: In randomized order, each participant will receive two IV infusions of ondansetron, 3 weeks apart; one with placebo (D5W), and one with tariquidar (4mg/kg dose in D5W) administered IV over 60 minutes. Ondansetron will be diluted in 100mL 0.9% normal saline, and tariquidar will be diluted in 500mL D5W.
|
|---|---|---|
|
Nervous system disorders
Headache
|
30.4%
7/23 • Number of events 7 • 6 weeks
|
29.2%
7/24 • Number of events 7 • 6 weeks
|
|
Gastrointestinal disorders
Metallic Taste
|
34.8%
8/23 • Number of events 8 • 6 weeks
|
8.3%
2/24 • Number of events 2 • 6 weeks
|
|
Gastrointestinal disorders
Constipation
|
4.3%
1/23 • Number of events 1 • 6 weeks
|
8.3%
2/24 • Number of events 2 • 6 weeks
|
|
Nervous system disorders
Drowsiness
|
30.4%
7/23 • Number of events 7 • 6 weeks
|
8.3%
2/24 • Number of events 2 • 6 weeks
|
|
Nervous system disorders
Nausea
|
13.0%
3/23 • Number of events 3 • 6 weeks
|
20.8%
5/24 • Number of events 5 • 6 weeks
|
|
Gastrointestinal disorders
Dry Mouth
|
0.00%
0/23 • 6 weeks
|
8.3%
2/24 • Number of events 2 • 6 weeks
|
|
Nervous system disorders
Paraesthesia
|
8.7%
2/23 • Number of events 2 • 6 weeks
|
8.3%
2/24 • Number of events 2 • 6 weeks
|
|
Nervous system disorders
Dizziness
|
8.7%
2/23 • Number of events 2 • 6 weeks
|
4.2%
1/24 • Number of events 1 • 6 weeks
|
|
Nervous system disorders
Syncope
|
13.0%
3/23 • Number of events 3 • 6 weeks
|
0.00%
0/24 • 6 weeks
|
|
Skin and subcutaneous tissue disorders
Infusion site bruising
|
34.8%
8/23 • Number of events 8 • 6 weeks
|
0.00%
0/24 • 6 weeks
|
Additional Information
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place