A Phase 1 interventional study of Radiprodil and Carbamazepine in Healthy Adult Participants, sponsored by GRIN Therapeutics, Inc.. Active, not recruiting at 1 site in United States. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-21.
Sponsored by GRIN Therapeutics, Inc. · Phase 1, Interventional, and Basic science
This is a Phase 1, open-label, 2-part study in healthy adult participants to evaluate the pharmacokinetics and safety of radiprodil when coadministered with either the CYP3A4 inducer carbamazepine or the CYP3A4 inhibitor itraconazole. Up to 36 participants will be enrolled, with approximately 18 participants in Part A and 18 participants in Part B.
Part A will evaluate the effect of carbamazepine on the plasma pharmacokinetic profile of radiprodil. Participants will receive a single 30 mg oral dose of radiprodil under fed conditions, followed by multiple oral doses of carbamazepine, and then coadministration of radiprodil 30 mg with carbamazepine 300 mg.
Part B will evaluate the effect of itraconazole on the plasma pharmacokinetic profile of radiprodil. Participants will receive a single 15 mg oral dose of radiprodil under fed conditions, followed by multiple oral doses of itraconazole, and then coadministration of radiprodil 15 mg with itraconazole 200 mg.
GRIN Therapeutics, Inc. is the lead sponsor of 7 studies on the registry; 2 are open to participants now.
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Participants will receive a single oral dose of radiprodil 30 mg under fed conditions on Day 1. Carbamazepine will then be administered orally twice daily with food at escalating doses: 100 mg BID on Days 4 to 5, 200 mg BID on Days 6 to 7, and 300 mg BID on Days 8 to 15. On Day 16, radiprodil 30 mg will be coadministered with carbamazepine 300 mg under fed conditions. Carbamazepine 300 mg BID will continue on Days 17 to 18. Participants will be discharged on Day 21 and attend a follow-up visit 30 days ± 2 days after the last carbamazepine dose.
Drug: Radiprodil · Drug: Carbamazepine
Participants will receive a single oral dose of radiprodil 15 mg under fed conditions on Day 1. Itraconazole 200 mg once daily will be administered orally with food on Days 4 to 8. On Day 9, radiprodil 15 mg will be coadministered with itraconazole 200 mg under fed conditions. Itraconazole 200 mg once daily will continue on Days 10 to 11. Participants will be discharged on Day 12 and attend a follow-up visit 30 days ± 2 days after the last itraconazole dose.
Drug: Radiprodil · Drug: Itraconazole (200 mg)
Radiprodil administered orally as a single dose of 30 mg in Part A or 15 mg in Part B under fed conditions.
Also known as: RGH-896, Radiprodil oral suspension
Carbamazepine administered orally twice daily at doses of 100 mg, 200 mg, and 300 mg in Part A to evaluate the effect of CYP3A4 induction on the pharmacokinetics of radiprodil.
Itraconazole administered orally at 200 mg once daily in Part B to evaluate the effect of CYP3A4 inhibition on the pharmacokinetics of radiprodil.
AUClast of Radiprodil - Part A
Area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast) of radiprodil following administration of radiprodil alone on Day 1 and with carbamazepine on Day 16. The effect of carbamazepine will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part A: Day 1 through Day 19
AUCinf of Radiprodil - Part A
Area under the plasma concentration-time curve from time zero extrapolated to infinity (AUCinf) of radiprodil following administration of radiprodil alone on Day 1 and with carbamazepine on Day 16. The effect of carbamazepine will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part A: Day 1 through Day 19
Cmax of Radiprodil - Part A
Maximum observed plasma concentration (Cmax) of radiprodil following administration of radiprodil alone on Day 1 and with carbamazepine on Day 16. The effect of carbamazepine will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part A: Day 1 through Day 19
AUClast of Radiprodil - Part B
Area under the plasma concentration-time curve from time zero to the last quantifiable concentration (AUClast) of radiprodil following administration of radiprodil alone on Day 1 and with itraconazole on Day 9. The effect of itraconazole will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part B: Day 1 through Day 12
AUCinf of Radiprodil - Part B
Area under the plasma concentration-time curve from time zero extrapolated to infinity (AUCinf) of radiprodil following administration of radiprodil alone on Day 1 and with itraconazole on Day 9. The effect of itraconazole will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part B: Day 1 through Day 12
Cmax of Radiprodil - Part B
Maximum observed plasma concentration (Cmax) of radiprodil following administration of radiprodil alone on Day 1 and with itraconazole on Day 9. The effect of itraconazole will be assessed using the geometric mean ratio and 90% confidence interval.
Time frame: Part B: Day 1 through Day 12
AUClast of Carbamazepine - Part A
Area under the plasma concentration-time curve from time zero to the last quantifiable concentration of carbamazepine following administration alone and in combination with radiprodil.
Time frame: Part A: Day 16 (up to 12 hours post-dose)
AUCtau of Carbamazepine - Part A
Area under the plasma concentration-time curve over the 12-hour dosing interval (AUCtau) of carbamazepine following coadministration with radiprodil.
Time frame: Part A: Day 16 (up to 12 hours post-dose)
Cmax of Carbamazepine - Part A
Maximum observed plasma concentration (Cmax) of carbamazepine following coadministration with radiprodil.
Time frame: Part A: Day 16 (up to 12 hours post-dose)
Tmax of Carbamazepine - Part A
Time to reach maximum observed plasma concentration of carbamazepine following administration alone and in combination with radiprodil.
Time frame: Part A: Day 16 (up to 12 hours post-dose)
AUClast of Itraconazole - Part B
Area under the plasma concentration-time curve from time zero to the last quantifiable concentration of itraconazole following administration alone and in combination with radiprodil.
Time frame: Part B: Day 9 through Day 10 (up to 24 hours post-dose)
AUCtau of Itraconazole - Part B
Area under the plasma concentration-time curve over the dosing interval of itraconazole following administration alone and in combination with radiprodil.
Time frame: Part B: Day 9 through Day 10 (up to 24 hours post-dose)
Cmax of Itraconazole - Part B
Maximum observed plasma concentration of itraconazole following administration alone and in combination with radiprodil.
Time frame: Part B: Day 9 through Day 10 (up to 24 hours post-dose)
Tmax of Itraconazole - Part B
Time to reach maximum observed plasma concentration of itraconazole following administration alone and in combination with radiprodil.
Time frame: Part B: Day 9 through Day 10 (up to 24 hours post-dose)
Tmax of Radiprodil - Part A
Time to reach maximum observed plasma concentration of radiprodil. Assessed following administration of radiprodil alone and in combination with carbamazepine.
Time frame: Part A: Day 1 through Day 19
Terminal Elimination Half-Life (t½) of Radiprodil - Part A
Terminal elimination half-life of radiprodil, defined as the time required for plasma concentration to decrease by half during the terminal elimination phase. Assessed following administration of radiprodil alone and in combination with carbamazepine.
Time frame: Part A: Day 1 through Day 19
Apparent Total Body Clearance (CL/F) of Radiprodil - Part A
Apparent total body clearance of radiprodil following oral administration. Assessed following administration of radiprodil alone and in combination with carbamazepine.
Time frame: Part A: Day 1 through Day 19
Apparent Volume of Distribution (Vz/F) of Radiprodil - Part A
Apparent volume of distribution of radiprodil during the terminal elimination phase following oral administration. Assessed following administration of radiprodil alone and in combination with carbamazepine.
Time frame: Part A: Day 1 through Day 19
Tmax of Radiprodil - Part B
Time to reach maximum observed plasma concentration of radiprodil. Assessed following administration of radiprodil alone and in combination with itraconazole.
Time frame: Part B: Day 1 through Day 12
Terminal Elimination Half-Life (t½) of Radiprodil - Part B
Terminal elimination half-life of radiprodil, defined as the time required for plasma concentration to decrease by half during the terminal elimination phase. Assessed following administration of radiprodil alone and in combination with itraconazole.
Time frame: Part B: Day 1 through Day 12
Apparent Total Body Clearance (CL/F) of Radiprodil - Part B
Apparent total body clearance of radiprodil following oral administration. Assessed following administration of radiprodil alone and in combination with itraconazole.
Time frame: Part B: Day 1 through Day 12
Apparent Volume of Distribution (Vz/F) of Radiprodil - Part B
Apparent volume of distribution of radiprodil during the terminal elimination phase following oral administration. Assessed following administration of radiprodil alone and in combination with itraconazole.
Time frame: Part B: Day 1 through Day 12
Number of Participants With Treatment-Emergent Adverse Events (TEAEs)
Number and percentage of participants with at least one treatment-emergent adverse event (TEAE), summarised by treatment period and overall for each study part. TEAEs are adverse events occurring or worsening after the first dose of study drug.
Time frame: From first dose of study drug through follow-up (up to approximately 90 days in Part A and 69 days in Part B)
Number of Participants With Serious Adverse Events (SAEs)
Number of participants experiencing at least one serious adverse event, summarised separately for each study part.
Time frame: From signing of informed consent through follow-up (up to approximately 90 days in Part A and 69 days in Part B)
Change From Baseline in Systolic Blood Pressure
Change from baseline in systolic blood pressure, measured in mmHg, summarised by scheduled assessment time point and treatment period within each study part.
Time frame: From baseline through follow-up
Change From Baseline in Diastolic Blood Pressure
Change from baseline in diastolic blood pressure, measured in mmHg, summarised by scheduled assessment time point and treatment period within each study part.
Time frame: From baseline through follow-up
Change From Baseline in Pulse Rate
Change from baseline in pulse rate, measured in beats per minute, summarised by scheduled assessment time point and treatment period within each study part.
Time frame: From baseline through follow-up
Change From Baseline in Body Temperature
Change from baseline in body temperature, measured in degrees Celsius, summarised by scheduled assessment time point and treatment period within each study part.
Time frame: From baseline through follow-up
Change From Baseline in Respiratory Rate
Change from baseline in respiratory rate, measured in breaths per minute, summarised by scheduled assessment time point and treatment period within each study part.
Time frame: From baseline through follow-up
Number of Participants With QTcF Interval Above 450 Milliseconds
Number of participants with a QT interval corrected using Fridericia's formula (QTcF) greater than 450 milliseconds during the study.
Time frame: From baseline through follow-up
Number of Participants With QTcF Interval Above 480 Milliseconds
Number of participants with a QTcF interval greater than 480 milliseconds during the study.
Time frame: From baseline through follow-up
Number of Participants With QTcF Interval Above 500 Milliseconds
Number of participants with a QTcF interval greater than 500 milliseconds during the study.
Time frame: From baseline through follow-up
Number of Participants With QTcF Increase From Baseline of at Least 30 Milliseconds
Number of participants with an increase in QTcF from baseline of at least 30 milliseconds during the study.
Time frame: From baseline through follow-up
Number of Participants With QTcF Increase From Baseline of at Least 60 Milliseconds
Number of participants with an increase in QTcF from baseline of at least 60 milliseconds during the study.
Time frame: From baseline through follow-up
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Studies of the drugs tested here: Carbamazepine · Itraconazole
GRIN Therapeutics, Inc.