Healthy VolunteersPhase 1NCT05098041

A Study of Soticlestat and Rifampin in Healthy Adults

A Phase 1 study testing Soticlestat and Rifampin in people with Healthy Volunteers, run by Takeda at 1 site in United Kingdom.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The main aim of this study is to check how rifampin affects the way soticlestat is processed by the body. Participants will be required to stay at the study clinic for 18 consecutive days. On the first full day and 15th day, participants will take a single dose of soticlestat. Read more about this study

Who is it for?: Ages 18 to 55 yearsHealthy volunteers can take part
Conditions the study is for: Healthy Volunteers
What is being tested?: Soticlestat and Rifampin
Type of treatment: Pill or oral medicine
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 15 participants
Where: 1 siteUnited Kingdom
Study dates: 22 Nov 2021to 3 Mar 2022
Phase: Phase 1
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 55 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Healthy, adult, male or female of non-childbearing potential, 18-55 years of age, inclusive, at screening.
Has body mass index (BMI) greater than or equal to (>=) 18.0 and less than or equal to (<=) 32.0 kilogram per square meter (kg/m^2) at screening.
Continuous non-smoker who has not used nicotine-containing products for at least 90 days prior to the first dosing.
Able to swallow multiple tablets/capsules.

Who cannot join

Has history of any illness that, in the opinion of the Investigator or designee, might confound the results of the study or poses an additional risk to the participant by their participation in the study.
Any positive responses on the C-SSRS that in the clinical judgment of the Investigator has a risk of suicide or has made a suicide attempt in the previous 12 months prior to the first dosing.
Unable to refrain from or anticipates the use of:
Any drug, including prescription and non-prescription medications, herbal remedies, or vitamin supplements within 14 days prior to the first dosing. Thyroid hormone replacement medication may be permitted if the participant has been on the same stable dose for the immediate 3 months prior to first dosing.
Any drugs known to be significant inducers of cytochrome (CYP)3A, CYP2C19, UGT1A9 or UGT2B4 enzymes, and/or P-glycoprotein (P-gp), including St. John's Wort, within 28 days prior to the first dosing.
Appropriate sources (example, Flockhart TableTM) will be consulted to confirm lack of pharmacokinetic (PK)/pharmacodynamics interaction with study drug.

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History of alcohol consumption exceeding 2 standard drinks per day on average (1 glass is approximately equivalent to the following: beer 354 milliliter [mL]/12 ounce [oz], wine [118 mL/4 oz], or distilled spirits [29.5 mL/1 oz] per day).
Consumes excessive amounts, defined as greater than 4 servings (1 serving is approximately equivalent to 120 mg of caffeine), of coffee, tea, cola, energy drinks, or other caffeinated beverages per day.
Has been on a diet incompatible with the on-study diet, in the opinion of the Investigator or designee, within the 30 days prior to the first dosing and throughout the study.
Donation of blood or significant blood loss within 56 days prior to the first dosing.
Plasma donation within 7 days prior to the first dosing.
Participation in another clinical study within 30 days or 5 half-lives prior to the first dosing. The 30-days window or 5 half-lives will be derived from the date of the last blood collection or dosing, whichever is later, in the previous study to Day 1 of Period 1 of the current study.

Trial locations and contacts

1 site in 1 country.

United Kingdom1 site

Celerion
Belfast, BT9 6AD

Other trials in United Kingdom

About this study

Official title: A Phase 1 Open-Label Study to Evaluate the Drug-Drug Interaction of Rifampin as a Strong CYP3A Inducer on Soticlestat Pharmacokinetics in Healthy Adult Participants

The main aim of this study is to check how rifampin affects the way soticlestat is processed by the body.

Participants will be required to stay at the study clinic for 18 consecutive days. On the first full day and 15th day, participants will take a single dose of soticlestat. Rifampin will be taken each day starting on the 5th day for 13 consecutive days.

Clinic staff will follow up with each participant about 15 days after the last soticlestat dose to check for any side effects.

Read the detailed description

The drug being tested in this study is called soticlestat (TAK-935). The study will evaluate the safety and tolerability of soticlestat when co-administered with rifampin in healthy participants.

The study will enroll 14 participants. The participants will be assigned to treatment group to receive following therapies:

Soticlestat 300 milligram (mg) + Rifampin 600 mg

The study will have two periods: Period 1 and Period 2. In Period 1, participants will receive soticlestat in fasted condition while in Period 2 participants will receive soticlestat along with rifampin. The data will be collected and stored in electronic case report form (eCRF).

This single-center trial will be conducted in the United Kingdom. The overall study duration of the study will be approximately 58 days including 28 days screening and follow up duration. There will be a follow up contact required for all participants approximately 15 days after the last dose of soticlestat.

Conditions: Healthy Volunteers
Being tested: Soticlestat, Rifampin
Keywords: Drug therapy

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

SoticlestatDrug
Also called TAK-935
Soticlestat tablets.
RifampinDrug
Rifampin capsules.

Study groups in NCT05098041
Study group	Role	What they receive
Soticlestat 300 mg + Rifampin 600 mg	Experimental	Soticlestat 3100 mg tablets, orally, administered once on Day 1 in fasted state in Period 1, followed by a washout period of 4 days, further followed by Rifampin 600 mg, administered as 2300mg capsules, orally, once daily for 13 consecutive days, from Day 1 to Day 13 in fasted state in Period 2. Soticlestat 3100 mg tablets, will be administered orally along with rifampin 600 mg (2300mg) capsules, orally in the morning of Day 11 in Period 2. Receives: Drug: Soticlestat; Drug: Rifampin

What is being measured

The primary outcome is the main question the study is designed to answer.

Cmax: Maximum Observed Plasma Concentration for Soticlestat When Administered Alone and With Rifampin
Measured: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
AUC∞: Area Under the Plasma Concentration-time Curve From Time 0 to Infinity for Soticlestat When Administered Alone and With Rifampin
Measured: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
AUClast: Area Under the Plasma Concentration-time Curve From Time 0 to the Time of the Last Quantifiable Concentration for Soticlestat When Administered Alone and With Rifampin
Measured: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
Tmax: Time to Reach the Maximum Plasma Concentration (Cmax) for Soticlestat When Administered Alone and With Rifampin
Measured: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2

Secondary outcomes (1)

Number of Participants Reported One or More Treatment-Emergent Adverse Events (TEAEs)
Measured: From Day 1 of Period 1 up to 15 days after the last dose of Soticlestat in Period 2 (up to Day 31)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

22 Nov 20213 Mar 2022

First posted28 Oct 2021
Study start22 Nov 2021
Primary completion16 Feb 2022
Study completion3 Mar 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Healthy VolunteersStudies of the same condition, open and under way.
More trials run by TakedaThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 1
Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Sequential
Masking: None (open label)
Enrolment: 15 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05098041
Sponsor's protocol ID: TAK-935-1009
Status last verified: Aug 2026
First submitted: 20 Oct 2021
Last updated: 10 Sep 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

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Study at a glance

From the registry record, last updated by the sponsor on 10 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase 1 Open-Label Study to Evaluate the Drug-Drug Interaction of Rifampin as a Strong CYP3A Inducer on Soticlestat Pharmacokinetics in Healthy Adult Participants
ClinicalTrials.gov ID: NCT05098041
Acronym / sponsor ID: TAK-935-1009
Conditions: Healthy Volunteers
Keywords: Drug therapy
Phase: Phase 1
Study type: Interventional
Recruitment status: Completed
Enrolment: 15 participants (actual)
Lead sponsor: TakedaIndustry (pharma, biotech, devices)
Study start: 22 Nov 2021 (actual)
Primary completion: 16 Feb 2022 (actual)
Study completion: 3 Mar 2022 (actual)
First posted: 28 Oct 2021 (actual)
Results: Posted 22 Nov 2023

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The main aim of this study is to check how rifampin affects the way soticlestat is processed by the body.

Clinic staff will follow up with each participant about 15 days after the last soticlestat dose to check for any side effects.

Detailed description

The drug being tested in this study is called soticlestat (TAK-935). The study will evaluate the safety and tolerability of soticlestat when co-administered with rifampin in healthy participants.

The study will enroll 14 participants. The participants will be assigned to treatment group to receive following therapies:

Soticlestat 300 milligram (mg) + Rifampin 600 mg

Study design

Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Sequential
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
Soticlestat 300 mg + Rifampin 600 mg	Experimental	Drug: Soticlestat, Drug: RifampinSoticlestat 3100 mg tablets, orally, administered once on Day 1 in fasted state in Period 1, followed by a washout period of 4 days, further followed by Rifampin 600 mg, administered as 2300mg capsules, orally, once daily for 13 consecutive days, from Day 1 to Day 13 in fasted state in Period 2. Soticlestat 3100 mg tablets, will be administered orally along with rifampin 600 mg (2300mg) capsules, orally in the morning of Day 11 in Period 2.

Who may qualify

Ages: 18 to 55 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (4 listed)

Healthy, adult, male or female of non-childbearing potential, 18-55 years of age, inclusive, at screening.
Has body mass index (BMI) greater than or equal to (>=) 18.0 and less than or equal to (<=) 32.0 kilogram per square meter (kg/m^2) at screening.
Continuous non-smoker who has not used nicotine-containing products for at least 90 days prior to the first dosing.
Able to swallow multiple tablets/capsules.

Key exclusion criteria (12 listed)

Has history of any illness that, in the opinion of the Investigator or designee, might confound the results of the study or poses an additional risk to the participant by their participation in the study.
Any positive responses on the C-SSRS that in the clinical judgment of the Investigator has a risk of suicide or has made a suicide attempt in the previous 12 months prior to the first dosing.
Unable to refrain from or anticipates the use of:
Appropriate sources (example, Flockhart TableTM) will be consulted to confirm lack of pharmacokinetic (PK)/pharmacodynamics interaction with study drug.
History of alcohol consumption exceeding 2 standard drinks per day on average (1 glass is approximately equivalent to the following: beer 354 milliliter [mL]/12 ounce [oz], wine [118 mL/4 oz], or distilled spirits [29.5 mL/1 oz] per day).

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
SoticlestatAlso: TAK-935Soticlestat tablets.	Drug	Soticlestat 300 mg + Rifampin 600 mg
RifampinRifampin capsules.	Drug	Soticlestat 300 mg + Rifampin 600 mg

Primary outcome

Cmax: Maximum Observed Plasma Concentration for Soticlestat When Administered Alone and With Rifampin
Time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
AUC∞: Area Under the Plasma Concentration-time Curve From Time 0 to Infinity for Soticlestat When Administered Alone and With Rifampin
Time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
AUClast: Area Under the Plasma Concentration-time Curve From Time 0 to the Time of the Last Quantifiable Concentration for Soticlestat When Administered Alone and With Rifampin
Time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2
Tmax: Time to Reach the Maximum Plasma Concentration (Cmax) for Soticlestat When Administered Alone and With Rifampin
Time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2

1 secondary outcome

Number of Participants Reported One or More Treatment-Emergent Adverse Events (TEAEs)
Time frame: From Day 1 of Period 1 up to 15 days after the last dose of Soticlestat in Period 2 (up to Day 31)

Results and safety

Results posted to the registry on 22 Nov 2023, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
All Participants: Soticlestat 300 mg + Rifampin 600 mg + Soticlestat 300 mg	15	14

Primary outcome: Cmax: Maximum Observed Plasma Concentration for Soticlestat When Administered Alone and With Rifampin

Time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2. Geometric mean (Geometric Coefficient of Variation). Unit: nanogram per milliliter (ng/mL)

Measure	Soticlestat 300 mg Alone n = 15	Soticlestat 300 mg + Rifampin 600 mg n = 14
Value	1364 (63.6)	176.8 (99.6)

Soticlestat 300 mg Alone vs Soticlestat 300 mg + Rifampin 600 mg: Geometric Mean Ratio (%): 13.15 (90% CI 9.73 to 17.79)

Population analysed: The pharmacokinetic (PK) set included participants who complied sufficiently with the protocol and display an evaluable PK profile (example, exposure to treatment, availability of measurements and absence of major protocol violations).

Primary outcome: AUC∞: Area Under the Plasma Concentration-time Curve From Time 0 to Infinity for Soticlestat When Administered Alone and With Rifampin

Measure	Soticlestat 300 mg Alone n = 13	Soticlestat 300 mg + Rifampin 600 mg n = 11
Value	1448 (47.0)	226.2 (94.0)

Soticlestat 300 mg Alone vs Soticlestat 300 mg + Rifampin 600 mg: Geometric Mean Ratio (%): 16.42 (90% CI 12.53 to 21.50)

Population analysed: The PK set included participants who complied sufficiently with the protocol and display an evaluable PK profile (example, exposure to treatment, availability of measurements and absence of major protocol violations). Here, "overall number of participants analyzed" signified those who were evaluable for this outcome measure.

Primary outcome: AUClast: Area Under the Plasma Concentration-time Curve From Time 0 to the Time of the Last Quantifiable Concentration for Soticlestat When Administered Alone and With Rifampin

Measure	Soticlestat 300 mg Alone n = 15	Soticlestat 300 mg + Rifampin 600 mg n = 14
Value	1290 (52.9)	190.6 (88.2)

Soticlestat 300 mg Alone vs Soticlestat 300 mg + Rifampin 600 mg: Geometric Mean Ratio (%): 14.92 (90% CI 11.94 to 18.64)

Primary outcome: Tmax: Time to Reach the Maximum Plasma Concentration (Cmax) for Soticlestat When Administered Alone and With Rifampin

Measure	Soticlestat 300 mg Alone n = 15	Soticlestat 300 mg + Rifampin 600 mg n = 14
Value	0.504 (0.24 to 0.76)	0.499 (0.27 to 0.75)

Soticlestat 300 mg Alone vs Soticlestat 300 mg + Rifampin 600 mg: Median Difference (Final Values): -0.117 (90% CI -0.202 to 0.000), p =0.07910, Wilcoxon Signed-Rank Test

1 secondary outcome is reported in the full results.

Adverse events

Time frame: TEAEs were adverse events (AE) that started from Day 1 of Period 1 up to 15 days after the last dose of Soticlestat in Period 2 (up to Day 31). Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Soticlestat 300 mg Alone	0 of 15 (0%)	2 of 15 (13.3%)	0 of 15
Rifampin 600 mg Alone	0 of 14 (0%)	1 of 14 (7.1%)	0 of 14
Soticlestat 300 mg + Rifampin 600 mg	0 of 14 (0%)	2 of 14 (14.3%)	0 of 14

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 10 Sep 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
To obtain more information on the study, click here/on this linkLink provided by the sponsor.
Individual participant dataSharing planned: Yes. Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Study Director study director

Takeda (Note: This product was divested to Mistrau Bio, Inc. in 2026)

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing Soticlestat and Rifampin in people with Healthy Volunteers, run by Takeda at 1 site in United Kingdom.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 12 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 10 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 22 Nov 2023). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Cmax: Maximum Observed Plasma Concentration for Soticlestat When Administered Alone and With Rifampin (time frame: Soticlestat Alone: Day 1 pre-dose and at multiple timepoints (up to 96 hours) post-dose in Period 1; Soticlestat with Rifampin: Day 11 pre-dose and at multiple time points (up to 72 hours) post-dose in Period 2). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05098041.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Sep 2026.