Developmental and/or Epileptic EncephalopathiesPhase 1/2NCT03166215
Study of TAK-935 as an Adjunctive Therapy in Participants With Developmental and/or Epileptic Encephalopathies
A Phase 1/2 study testing TAK-935 in people with Developmental and/or Epileptic Encephalopathies, run by Takeda at 11 sites in United States.
Trial summary
The purpose of this study is to characterize the multiple-dose safety and tolerability profile of TAK-935 in adult participants with developmental and/or epileptic encephalopathies. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Developmental and/or Epileptic Encephalopathies
- What is being tested?
- TAK-935
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 18 participants
- Where
- 11 sitesUnited States
- Study dates
- 17 Aug 2017to 19 Sep 2018
- Phase
- Phase 1/2
- 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 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Has a documented clinical diagnosis of developmental and/or epileptic encephalopathies with countable bilateral motor seizures, defined as an average of greater than or equal to (>=) 2 per month during the past 3 months, based on the investigator's assessment, and a monthly average of >=1 per month during the Baseline Period, based on the seizure diary record.
- Has been taking 1 to 4 antiepileptic drug (AEDs) at a stable dose for >=4 weeks before Screening and the participant or participant's legally acceptable representative is willing to keep the regimen(s) stable throughout the study.
- Has an average of >=1 bilateral motor seizure per month during the 4-week Baseline Period (that is., drop seizures, tonic-clonic, tonic, bilateral clonic, atonic, myoclonic-atonic, myoclonic-tonic-clonic, focal seizures with bilateral hyperkinetic motor features).
- Must agree to not post any participant's personal medical data related to the study or information related to the study on any web site or social media site (example, Facebook, Twitter) until the study has been completed.
- For participants with G-tube/PEG tube, G-tubes/PEG tubes should have been placed and been functioning for at least 3 months prior to screening. Naso-gastric tubes are not allowed.
Who cannot join
- Has received TAK-935 in a previous clinical study or as a therapeutic agent.
- Was admitted to a medical facility for treatment of status epilepticus requiring mechanical respiration within 3 months before Screening.
- Had a vagal nerve stimulator implanted within 6 months before Screening and settings have been changed within 1 month of the Screening Visit and/or anticipated to change during the study.
- Is on ketogenic diet that has been started within 6 months of the Screening Visit, has been changed within 1 month of the Screening Visit, or is anticipated to change during the study.
- Has degenerative eye disease.
- Has a history of suicidal behavior or any suicidal ideation of type 4 or 5 on the Columbia-Suicide Severity Rating Scale (C-SSRS) at Screening. If the participant is unable to comply with the C-SSRS due to developmental status, a parent proxy may be used for the completion of the C-SSRS. The Investigator may also use clinical judgment, which must then be documented in the source document.
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- Positive for human immunodeficiency virus, hepatitis B, or hepatitis C infections. (Note that participants who have been vaccinated against hepatitis B [hepatitis B surface antibody (Ab)-positive] who are negative for other markers of prior hepatitis B infection [example, negative for hepatitis B core Ab] are eligible. Also note that participants who are positive for hepatitis C Ab are eligible as long as they have a negative hepatitis C viral load by quantitative polymerase chain reaction [qPCR]).
- Has an abnormal and clinically significant ECG at Screening in the opinion of the investigator, for example, second or third degree heart block or a corrected QT interval (QTc) greater than (>) 450 millisecond (msec). Entry of any participant with an abnormal but not clinically significant ECG must be approved and documented by signature by the principal investigator or appropriately qualified delegate.
- Has abnormal clinical laboratory test results at Screening that suggest a clinically significant underlying disease. If the participant has alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) >2.5*the upper limit of normal (ULN), the Medical Monitor should be consulted.
- Has received any excluded medications, procedures, or treatments during the time periods.
- Has any a history of alcohol, opioid, or other drug use disorder, as per the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, within the previous 2 years before Screening. Medical marijuana use is allowed.
- Has unstable, clinically significant neurologic (other than the disease being studied), psychiatric, cardiovascular, pulmonary, hepatic, renal, metabolic, gastrointestinal, urologic, immunologic, hematopoietic, or endocrine disease or other abnormality, which may impact the ability of the participant to participate or potentially confound the study results.
Trial locations and contacts
11 sites in 1 country.
11 sites in 1 country
United States11 sites
Center for Integrative Rare Disease Research
Atlanta, Georgia, 30318
Mid-Atlantic Epilepsy and Sleep Center
Bethesda, Maryland, 20817
Medical University of South Carolina
Charleston, South Carolina, 29425
University of Virginia Health Sciences Center
Charlottesville, Virginia, 22903
Northeast Regional Epilepsy Group
Hackensack, New Jersey, 07601
Bluegrass Epilepsy Research
Lexington, Kentucky, 40504
Thomas Jefferson University
Philadelphia, Pennsylvania, 19107
Xenoscience
Phoenix, Arizona, 85004
Medsol Clinical Research Center
Port Charlotte, Florida, 33952
The Comprehensive Epilepsy Care Center for Children and Adults
St Louis, Missouri, 63131
University of South Florida
Tampa, Florida, 33606
About this study
Official title: A Phase 1b/2a Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group, Dose-Escalation Study With an Open-Label Part to Examine the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of TAK-935 as an Adjunctive Therapy in Subjects With Developmental and/or Epileptic Encephalopathies
The purpose of this study is to characterize the multiple-dose safety and tolerability profile of TAK-935 in adult participants with developmental and/or epileptic encephalopathies.
Read the detailed description
The drug being tested in this study is called TAK-935. TAK-935 is being tested to treat people who have developmental and/or epileptic encephalopathies. This study will look at safety, tolerability and pharmacokinetics of people who take TAK-935. Study drug will be administered in a double-blind manner in Part 1 and in an open-label manner in Part 2.
The study will enroll approximately 20 participants. Participants will be randomly assigned (by chance, like flipping a coin) to one of the two treatment groups in Part 1-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need):
- TAK-935
- Placebo (dummy inactive pill) - this is a tablet that looks like the study drug but has no active ingredient
Participants will receive placebo or 100 milligram (mg) TAK-935 tablets, orally or through stable G-tube/PEG tube, BID, in Part 1 (Day 1) and dose will be increased to 200 mg (Day 11) BID and to 300 mg (Day 21) BID in dose titration period. All participants who complete the Double-Blind Treatment Period in Part 1 will have the option to continue directly into the Open-Label Treatment Period in Part 2 where they will receive TAK-935 as two 100 mg tablets (total dose is 200 mg TAK-935) orally or through G-tube/PEG tube, BID and dose will be increased to three 100 mg tablets (total dose is 300 mg TAK-935), orally, BID (Day 41). This dose level will be maintained until the final visit (Day 85) for the dose de-escalation phase.
This multi-center trial will be conducted in North America. The overall time to participate in this study is 121 days excluding screening period of 30-41 days. Participants will make multiple visits to the clinic, and a follow-up phone call will be conducted on Day 91 and at the end of the 30-day follow-up period (Day 121), participants will return to the clinic for a follow-up assessment.
- Being tested
- TAK-935, Placebo
- Keywords
- Drug therapy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
TAK-935Drug
TAK-935 tablets.
PlaceboDrug
TAK-935 placebo-matching tablets.
| Study group | Role | What they receive |
|---|---|---|
| Part 1: Placebo | Placebo comparator | TAK-935 matching-placebo tablets, orally or through gastrostomy tube (G-tube)/ percutaneous endoscopic gastrostomy (PEG) tube, twice daily (BID) from Days 1 to 30 in dose titration period. Receives: Drug: TAK-935 |
| Part 1: TAK-935 | Experimental | TAK-935 100 mg, tablet, orally or through G-tube/PEG tube, BID from Days 1 to 10 followed by TAK-935 100 mg tablets x2, orally or through G-tube/PEG tube, BID from Days 11 to 20 followed by TAK-935 100 mg tablets x3, orally or through G-tube/PEG tube, BID from Days 21 to 30 in dose titration period. The dose of TAK-935 was escalated or de-escalated during Part 1 as per investigator's discretion. Receives: Drug: Placebo |
| Part 2: TAK-935 | Experimental | TAK-935 100 mg tablets x2, orally or through G-tube/PEG tube, BID from Days 31 to 40 followed by TAK-935 100 mg tablets x1, x2 or x3, orally or through G-tube/PEG tube, BID from Days 31 to Day 85 as per investigator's discretion in the maintenance period. At the end of Part 2, the dose of TAK-935 was de-escalated until discontinuation. Receives: Drug: TAK-935 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Participants With at Least One Treatment-Emergent Adverse Event (TEAE), as Reported by the Participants or Participant's Caregivers or Observed by the Investigator, After TAK-935 Treatment
An Adverse Event (AE) is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (eg, a clinically significant abnormal laboratory finding), symptom, or disease temporally associated with the use of a drug, whether or not it is considered related to the drug. A treatment-emergent adverse event (TEAE) is defined as an adverse event with an onset that occurs after receiving study drug
Measured: From first dose up to 30 days post last dose (approximately up to 120 days)
Secondary outcomes (10)
Drug Clearance (CL) and Intercompartmental Clearance (Q) for TAK-935 Calculated Using the Observed Value of the Last Quantifiable Concentration
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Apparent Volume of Distribution (Vz/F) of Central Compartment (Vc) and Peripheral Compartment (Vp) for TAK-935 Calculated Using the Observed Value of the Last Quantifiable Concentration
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Absorption Rate Constant (Ka) for TAK-935
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Cmax,ss: Maximum Observed Plasma Concentration for TAK-935 at Steady State
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
AUC0-tau,ss: Area Under the Plasma Concentration-time Curve Over the Dosing Interval for TAK-935 at Steady State
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Cav,ss: Average Plasma Concentration During a Dosing Interval at Steady State for TAK-935
Measured: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Ctrough,ss: Plasma Concentration Immediately Prior to Dosing for TAK-935 at Steady State
Measured: Days 1, 11, 21; Days 31, 41 and 85 pre-dose
Percentage of Participants With at Least 1 Markedly Abnormal Value for Clinical Laboratory Evaluations After TAK-935
Clinical Laboratory parameters: hematology, serum chemistry and urinalysis. Participants with at least 1 markedly abnormal values during treatment period were reported: Erythrocytes: <0.8xLLN->1.5xULN, Hematocrit: <0.8x LLN >1.2xULN,Hemoglobin: <0.8xLLN->1.2xULN Leukocytes: <0.5xLLN, Platelets (10^9/L): <75x10^9/L->600x10^9/L, Prothrombin Ratio: >1.5xULN, Alanine Aminotransferase: >3xULN, Albumin:<25 g/L, Alkaline Phosphatase: >3xULN,Alpha-1 Acid Glycoprotein: <47 mg/DL->125 mg/DL, Aspartate Aminotransferase:>3xULN, Bicarbonate:<8.0 mmol/L, Calcium:<1.75 mmol/L->2.88 mmol/L, Chloride:<75 mmol/L->126 mmol/L, Cholesterol: >7.72,Creatine Kinase:>5xULN, Creatinine:>177 umol/L, Gamma Glutamyl Transferase: >3xULN, Glucose:<2.8 mmol/L- >19.4 mmol/L,HDL Cholesterol: <1.04 mmol/L->1.55 mmol/L, LDL Cholesterol: <1.30 mmol/L->4.14 mmol/L, Potassium:<3.0 mmol/L->6.0 mEq/L, Protein:<0.8xLLN->1.2 x ULN, Sodium: <130 mmol/L->150 mmol/L, Triglycerides: >2.5xULN, Urea Nitrogen: >10.7 mmol/L.
Measured: From first dose up to last dose (up to Day 85)
Percentage of Participants With at Least 1 Markedly Abnormal Value for Vital Signs After TAK-935
Vital signs included heart rate, blood pressure and body temperature. markedly abnormal values during treatment period were categorized as: heart rate 1,3 and 5 min standing (beats/min) <50->120, systolic blood pressure 1,3 and 5 min standing (mmHg) <85->180, diastolic blood pressure 1,3 and 5 min standing (mmHg) <50->110 and body temperature (degree centigrade) <35.6- >37.7. Only categories with values have been reported.
Measured: From first dose up to 30 days post last dose (approximately up 120 days)
Percentage of Participants With at Least 1 Markedly Abnormal Value for Electrocardiogram (ECG) Parameters After TAK-935
A 12-lead ECG was performed. Markedly abnormal values during treatment period were categorized as: ECG ventricular rate <50->120, PR Interval, (msec) <=80->=200, QRS Duration, (msec) <=80->=180, QT Interval, (msec) <=50->=460, QTcF Interval, (msec) <=50->=500 OR >=30 change from baseline and >=450 milliseconds, RR interval <600->=1440.
Measured: From first dose up to last dose (up to Day 85)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 May 2017
- Study start17 Aug 2017
- Primary completion19 Sep 2018
- Study completion19 Sep 2018
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.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Developmental and/or Epileptic EncephalopathiesStudies 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 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- Takeda
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Healx AI
- Responsible party
- Sponsor
- Investigators
- Medical Monitor Clinical Science, Study director, Takeda (Note: This product was divested to Mistrau Bio, Inc. in 2026)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03166215
- Sponsor's protocol ID
- TAK-935-2001
- Other IDs
- U1111-1192-7890
- Status last verified
- Aug 2026
- First submitted
- 23 May 2017
- Last updated
- 14 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.
Publications
Halford JJ, Sperling MR, Arkilo D, Asgharnejad M, Zinger C, Xu R, During M, French JA. A phase 1b/2a study of soticlestat as adjunctive therapy in participants with developmental and/or epileptic encephalopathies. Epilepsy Res. 2021 Aug;174:106646. doi: 10.1016/j.eplepsyres.2021.106646. Epub 2021 Apr 22.
PubMed 33940389
Study at a glance
From the registry record, last updated by the sponsor on 14 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1b/2a Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group, Dose-Escalation Study With an Open-Label Part to Examine the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of TAK-935 as an Adjunctive Therapy in Subjects With Developmental and/or Epileptic Encephalopathies
- ClinicalTrials.gov ID
- NCT03166215
- Acronym / sponsor ID
- TAK-935-2001
- Keywords
- Drug therapy
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- TakedaIndustry (pharma, biotech, devices)
- Collaborators
- Healx AI
- Study start
- 17 Aug 2017 (actual)
- Primary completion
- 19 Sep 2018 (actual)
- Study completion
- 19 Sep 2018 (actual)
- First posted
- 25 May 2017 (actual)
- Results
- Posted 10 Jan 2020
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to characterize the multiple-dose safety and tolerability profile of TAK-935 in adult participants with developmental and/or epileptic encephalopathies.
Detailed description
The drug being tested in this study is called TAK-935. TAK-935 is being tested to treat people who have developmental and/or epileptic encephalopathies. This study will look at safety, tolerability and pharmacokinetics of people who take TAK-935. Study drug will be administered in a double-blind manner in Part 1 and in an open-label manner in Part 2.
The study will enroll approximately 20 participants. Participants will be randomly assigned (by chance, like flipping a coin) to one of the two treatment groups in Part 1-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need):
- TAK-935
- Placebo (dummy inactive pill) - this is a tablet that looks like the study drug but has no active ingredient
Participants will receive placebo or 100 milligram (mg) TAK-935 tablets, orally or through stable G-tube/PEG tube, BID, in Part 1 (Day 1) and dose will be increased to 200 mg (Day 11) BID and to 300 mg (Day 21) BID in dose titration period. All participants who complete the Double-Blind Treatment Period in Part 1 will have the option to continue directly into the Open-Label Treatment Period in Part 2 where they will receive TAK-935 as two 100 mg tablets (total dose is 200 mg TAK-935) orally or through G-tube/PEG tube, BID and dose will be increased to three 100 mg tablets (total dose is 300 mg TAK-935), orally, BID (Day 41). This dose level will be maintained until the final visit (Day 85) for the dose de-escalation phase.
This multi-center trial will be conducted in North America. The overall time to participate in this study is 121 days excluding screening period of 30-41 days. Participants will make multiple visits to the clinic, and a follow-up phone call will be conducted on Day 91 and at the end of the 30-day follow-up period (Day 121), participants will return to the clinic for a follow-up assessment.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Part 1: Placebo | Placebo comparator | Drug: TAK-935TAK-935 matching-placebo tablets, orally or through gastrostomy tube (G-tube)/ percutaneous endoscopic gastrostomy (PEG) tube, twice daily (BID) from Days 1 to 30 in dose titration period. |
| Part 1: TAK-935 | Experimental | Drug: PlaceboTAK-935 100 mg, tablet, orally or through G-tube/PEG tube, BID from Days 1 to 10 followed by TAK-935 100 mg tablets x2, orally or through G-tube/PEG tube, BID from Days 11 to 20 followed by TAK-935 100 mg tablets x3, orally or through G-tube/PEG tube, BID from Days 21 to 30 in dose titration period. The dose of TAK-935 was escalated or de-escalated during Part 1 as per investigator's discretion. |
| Part 2: TAK-935 | Experimental | Drug: TAK-935TAK-935 100 mg tablets x2, orally or through G-tube/PEG tube, BID from Days 31 to 40 followed by TAK-935 100 mg tablets x1, x2 or x3, orally or through G-tube/PEG tube, BID from Days 31 to Day 85 as per investigator's discretion in the maintenance period. At the end of Part 2, the dose of TAK-935 was de-escalated until discontinuation. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Has a documented clinical diagnosis of developmental and/or epileptic encephalopathies with countable bilateral motor seizures, defined as an average of greater than or equal to (>=) 2 per month during the past 3 months, based on the investigator's assessment, and a monthly average of >=1 per month during the Baseline Period, based on the seizure diary record.
- Has been taking 1 to 4 antiepileptic drug (AEDs) at a stable dose for >=4 weeks before Screening and the participant or participant's legally acceptable representative is willing to keep the regimen(s) stable throughout the study.
- Has an average of >=1 bilateral motor seizure per month during the 4-week Baseline Period (that is., drop seizures, tonic-clonic, tonic, bilateral clonic, atonic, myoclonic-atonic, myoclonic-tonic-clonic, focal seizures with bilateral hyperkinetic motor features).
- Must agree to not post any participant's personal medical data related to the study or information related to the study on any web site or social media site (example, Facebook, Twitter) until the study has been completed.
- For participants with G-tube/PEG tube, G-tubes/PEG tubes should have been placed and been functioning for at least 3 months prior to screening. Naso-gastric tubes are not allowed.
Key exclusion criteria (12 listed)
- Has received TAK-935 in a previous clinical study or as a therapeutic agent.
- Was admitted to a medical facility for treatment of status epilepticus requiring mechanical respiration within 3 months before Screening.
- Had a vagal nerve stimulator implanted within 6 months before Screening and settings have been changed within 1 month of the Screening Visit and/or anticipated to change during the study.
- Is on ketogenic diet that has been started within 6 months of the Screening Visit, has been changed within 1 month of the Screening Visit, or is anticipated to change during the study.
- Has degenerative eye disease.
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 |
|---|---|---|
| TAK-935TAK-935 tablets. | Drug | Part 1: Placebo, Part 2: TAK-935 |
| PlaceboTAK-935 placebo-matching tablets. | Drug | Part 1: TAK-935 |
Primary outcome
Percentage of Participants With at Least One Treatment-Emergent Adverse Event (TEAE), as Reported by the Participants or Participant's Caregivers or Observed by the Investigator, After TAK-935 Treatment
Time frame: From first dose up to 30 days post last dose (approximately up to 120 days)
An Adverse Event (AE) is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (eg, a clinically significant abnormal laboratory finding), symptom, or disease temporally associated with the use of a drug, whether or not it is considered related to the drug. A treatment-emergent adverse event (TEAE) is defined as an adverse event with an onset that occurs after receiving study drug
10 secondary outcomes
Drug Clearance (CL) and Intercompartmental Clearance (Q) for TAK-935 Calculated Using the Observed Value of the Last Quantifiable Concentration
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Apparent Volume of Distribution (Vz/F) of Central Compartment (Vc) and Peripheral Compartment (Vp) for TAK-935 Calculated Using the Observed Value of the Last Quantifiable Concentration
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Absorption Rate Constant (Ka) for TAK-935
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Cmax,ss: Maximum Observed Plasma Concentration for TAK-935 at Steady State
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
AUC0-tau,ss: Area Under the Plasma Concentration-time Curve Over the Dosing Interval for TAK-935 at Steady State
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Cav,ss: Average Plasma Concentration During a Dosing Interval at Steady State for TAK-935
Time frame: Day 1 pre-dose and at multiple timepoints (up to 5 hours) post-dose; Days 11 and 21 pre-dose and 1-hour post-dose; Days 31, 41, and 85 pre-dose
Ctrough,ss: Plasma Concentration Immediately Prior to Dosing for TAK-935 at Steady State
Time frame: Days 1, 11, 21; Days 31, 41 and 85 pre-dose
Percentage of Participants With at Least 1 Markedly Abnormal Value for Clinical Laboratory Evaluations After TAK-935
Time frame: From first dose up to last dose (up to Day 85)
Percentage of Participants With at Least 1 Markedly Abnormal Value for Vital Signs After TAK-935
Time frame: From first dose up to 30 days post last dose (approximately up 120 days)
Percentage of Participants With at Least 1 Markedly Abnormal Value for Electrocardiogram (ECG) Parameters After TAK-935
Time frame: From first dose up to last dose (up to Day 85)
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Sep 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 33940389Halford JJ, Sperling MR, Arkilo D, Asgharnejad M, Zinger C, Xu R, During M, French JA. A phase 1b/2a study of soticlestat as adjunctive therapy in participants with developmental and/or epileptic encephalopathies. Epilepsy Res. 2021 Aug;174:106646. doi: 10.1016/j.eplepsyres.2021.106646. Epub 2021 Apr 22.
- 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.
Medical Monitor Clinical Science study director
Takeda (Note: This product was divested to Mistrau Bio, Inc. in 2026)
11 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing TAK-935 in people with Developmental and/or Epileptic Encephalopathies, run by Takeda at 11 sites in United States.
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 5 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 14 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 11 sites in United States. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined 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.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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 10 Jan 2020). 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?
Percentage of Participants With at Least One Treatment-Emergent Adverse Event (TEAE), as Reported by the Participants or Participant's Caregivers or Observed by the Investigator, After TAK-935 Treatment (time frame: From first dose up to 30 days post last dose (approximately up to 120 days)). 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 NCT03166215, which also lists 1 linked publication.
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 14 Sep 2026.