Bioavailability of Stiripentol After Single Oral Dose of Capsule vs Suspension in Healthy Subjects (STILIQ)

NCT07176832 | Completed Phase 1

• 2 other identifiers: STILIQ - STP 2182024-520103-38-00
• Study Type: interventional
• Target: 24
• Locations: 1 country
• Sites: 2

Brief Summary

This is a Phase I, open-label, randomized, single-center, two-way cross-over study evaluating the relative bioavailability, pharmacokinetics, safety, and palatability of two formulations of stiripentol (Diacomit®), indicated in Dravet syndrome. The investigational products are 500 mg capsules (reference) and a 50 mg/mL oral suspension (test). The primary objective is to compare the relative bioavailability of the two formulations after a single 1,000 mg oral dose under fed conditions, based on Cmax, AUC0-t, and AUC0-∞. Secondary objectives include other PK parameters (tmax, tlag, ke, t1/2) and characterization of metabolites MIa and MIb. Palatability of the suspension will be assessed by questionnaire. Safety evaluation will include adverse events, laboratory tests, ECGs, urinalysis, drug and alcohol screening, serology, and vital signs. Twenty-four healthy volunteers (18-50 years) will be enrolled. Eligibility: BMI 18-30 kg/m², weight ≥50 kg, normal ECG and labs, and informed consent. Women of childbearing potential must use effective contraception and test negative for pregnancy. Exclusions: significant disease, recent surgery or blood donation, hypersensitivity, difficulty swallowing, use of CYP modulators (e.g., carbamazepine, grapefruit, herbal products), drug or alcohol abuse, smoking \>5 cigarettes/day, or inability to follow dietary restrictions. Subjects testing positive for HIV, HBV, HCV, or drugs of abuse will also be excluded. Each participant will attend a screening visit within 28 days before dosing, then two 3-day hospitalizations separated by a 7-15-day washout. On Day 1 of each period, they will receive either two capsules (1,000 mg) or 20 mL suspension (1,000 mg). Blood will be collected at 36 timepoints (≈180 mL total) for PK assessment. The total study duration per subject is about seven weeks, including screening, hospitalization, dosing, washout, and follow-up. Treatment consists of one dosing day per period. Sample size was based on prior data: 21 pairs provide 80% power for bioequivalence within 0.80-1.25 bounds; 24 subjects will be recruited to account for dropouts. Analyses will include the Safety Set, PK Concentrations Set, and PK Analysis Set. This trial aims to establish whether the oral suspension provides a PK profile comparable to capsules, while generating safety, tolerability, and palatability data to support a more convenient formulation for Dravet syndrome patients.

Conditions

Dravet Syndrome; Epilepsy; Childhood; Epileptic Encephalopathy; Pediatric Epilepsy

Keywords

Stiripentol; Diacomit; Oral Suspension; Bioavailability; Pharmacokinetics; Antiepileptic Drug; Crossover Study; Healthy Volunteers; Pediatric Epilepsy; Dravet Syndrome Treatment

Outcome Measures

Primary Outcomes (1)

• Relative bioavailability of stiripentol oral suspension (50 mg/mL) vs capsule (500 mg) after a single 1,000 mg oral dose with food, assessed by PK parameters Cmax, AUC0-t, and AUC0-∞ using plasma LC-MS.

  The relative bioavailability of stiripentol oral suspension (50 mg/mL) versus capsule (500 mg) after a single 1,000 mg oral dose under fed conditions. It will be assessed by calculating geometric mean ratios with 90% confidence intervals for the main pharmacokinetic parameters: maximum observed plasma concentration (Cmax), area under the concentration-time curve from time zero to the last measurable concentration (AUC0-t), and area under the concentration-time curve extrapolated to infinity (AUC0-∞). Plasma concentrations of stiripentol will be measured using validated liquid chromatography-mass spectrometry (LC-MS) methods to ensure accuracy and reliability of the pharmacokinetic evaluation.

  Up to 36 hours post-dose (per period)

Secondary Outcomes (12)

• Other PK parameters of stiripentol

  Up to 36 hours post-dose (per period).

• Safety and tolerability of stiripentol

  From dosing to end of study (~7 weeks per participant).

• Palatability of stiripentol oral suspension

  20 minutes after administration of the oral suspension

• Other PK parameters of stiripentol

  Up to 36 hours post-dose (per period)

• Other PK parameters of stiripentol

  Up to 36 hours post-dose (per period)

Study Arms (2)

Sequence A : Stiripentol Capsule then Oral Suspension

EXPERIMENTAL

Subjects randomized to Sequence A will receive a single oral dose of 1,000 mg stiripentol (2 × 500 mg capsules, Diacomit®) at the end of breakfast under fed conditions in Period 1, followed by a single oral dose of 1,000 mg stiripentol (20 mL oral suspension, 50 mg/mL, Diacomit®) in Period 2 after a 7-15 day

Drug: Stiripentol capsule (Diacomit®); Drug: Stiripentol oral suspension (Diacomit®)

Sequence B : Stiripentol Oral Suspension then Capsule

EXPERIMENTAL

Subjects randomized to Sequence B will receive a single oral dose of 1,000 mg stiripentol (20 mL oral suspension, 50 mg/mL, Diacomit®) at the end of breakfast under fed conditions in Period 1, followed by a single oral dose of 1,000 mg stiripentol (2 × 500 mg capsules, Diacomit®) in Period 2 after a 7-15 day washout.

Drug: Stiripentol capsule (Diacomit®); Drug: Stiripentol oral suspension (Diacomit®)

Interventions

Stiripentol capsule (Diacomit®) DRUG

Single oral administration of 1,000 mg stiripentol (2 × 500 mg capsules) at the end of breakfast.

Also known as: Stiripentol 500 mg capsule, Diacomit® capsule

Sequence A : Stiripentol Capsule then Oral Suspension; Sequence B : Stiripentol Oral Suspension then Capsule

Stiripentol oral suspension (Diacomit®) DRUG

Single oral administration of 1,000 mg stiripentol (20 mL oral suspension, 50 mg/mL) at the end of breakfast.

Also known as: Stiripentol 50 mg/mL suspension, Diacomit® oral suspension

Sequence A : Stiripentol Capsule then Oral Suspension; Sequence B : Stiripentol Oral Suspension then Capsule

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Aged between 18 and 50 years (inclusive).
• Considered healthy after a comprehensive clinical assessment (medical history + complete physical exam).
• Body Mass Index (BMI) between 18 and 30 kg/m² (inclusive) and body weight ≥ 50 kg at screening.
• Normal blood pressure (BP) and heart rate (HR) after 10 minutes supine at screening : Systolic BP: 90-145 mmHg, Diastolic BP: 45-90 mmHg, HR: 40-90 bpm, Or values outside these ranges but judged not clinically significant (NCS) by the Investigator.
• Normal ECG at screening (10-min resting 12-lead ECG): PR interval: 110-210 ms, QRS interval : \< 120 ms, QTcF interval: ≤ 450 ms, No evidence of sinus node dysfunction, Or values outside these ranges but judged NCS by the Investigator.
• Laboratory parameters within normal ranges (hematology, biochemistry, urinalysis); slight deviations allowed if not clinically relevant per Investigator.
• Women of non-childbearing potential, or women of childbearing potential using at least one acceptable contraceptive method throughout the study and 1 month after last treatment.
• Female subjects of childbearing potential: negative pregnancy test (serum or urine) at screening and Day 0.
• Covered by Health Insurance System and/or compliant with National Law requirements for biomedical research.
• Able and willing to comply with study requirements.
• Written informed consent obtained.

You may not qualify if:

• Unsuitable veins for repeated venipuncture.
• Relevant history/presence of cardiovascular, pulmonary, gastrointestinal, hepatic, renal, metabolic, hematological, neurological, psychiatric, systemic, or infectious disease.
• Evidence of any clinically significant acute or chronic disease.
• History of suicidal ideation or suicide attempt.
• Surgery (including clinical trial procedures) within 2 months before dosing.
• Blood donation within 2 months before dosing.
• History/presence of drug hypersensitivity, asthma, or allergy.
• Known hypersensitivity to study materials or related compounds.
• Inability/difficulty swallowing capsules.
• No possibility of emergency contact.
• Any drug intake (except paracetamol) within 4 weeks prior to dosing or \< 5 half-lives (whichever longer). Prohibited: carbamazepine, phenytoin, phenobarbital, CYP enzyme modulators.
• Use of herbal products affecting CYP enzymes within 2 weeks or \< 5 half-lives before dosing.
• Special diets (vegetarian, vegan, gluten-free).
• Vigorous exercise from 4 days before dosing until post-study assessments.
• Pregnant or breastfeeding women.

Sponsors & Collaborators

• Biocodex: lead

Study Sites (2)

3 Chemin d'Armancourt

Compiègne, 60200, France

Location

EUROFINS OPTIMED, 1 rue des Essarts

Gières, 38610, France

Location

MeSH Terms

Conditions

Epilepsies, Myoclonic; Epilepsy

Interventions

stiripentol; Suspensions

Condition Hierarchy (Ancestors)

Epilepsy, Generalized; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Epileptic Syndromes

Intervention Hierarchy (Ancestors)

Colloids; Complex Mixtures; Dosage Forms; Pharmaceutical Preparations

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: A single center, two-way, 2 periods, open-label, cross-over, and randomized study

Study Record Dates

• First Submitted: August 29, 2025
• First Posted: September 16, 2025
• Study Start: June 1, 2025
• Primary Completion: August 27, 2025
• Study Completion: August 27, 2025
• Last Updated: September 16, 2025

Record last verified: 2025-09

Locations

FR (2)