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Focal SeizurePhase 2/3POWER1NCT06999902

Double-blind, Randomized Trial of PRAX-628 in Adults With Focal Seizures to Evaluate Efficacy and Safety (POWER1)

A Phase 2/3 study testing 20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeks in people with Focal Seizure, run by Praxis Precision Medicines at 69 sites in 7 countries.

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

A Double-Blind, Randomized, Multicenter, Trial Evaluating the Efficacy and Safety of PRAX-628 in Adults With Focal Seizures (POWER1) Read more about this study

Who is it for?
Ages 18 to 75 years
Conditions the study is for
Focal Seizure
What is being tested?
20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeks
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
255 participants
Where
69 sitesin 7 countries
Study dates
11 Dec 2024to 14 May 2026
Phase
Phase 2/3
Are there results?
None posted in the registry

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 75 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • A diagnosis of focal onset epilepsy according to the International League Against Epilepsy (ILAE) Classification of Epilepsy.
  • Past evidence by computed tomography (CT) or magnetic resonance imaging (MRI) that has ruled out a progressive cause of epilepsy in the judgement of the investigator and/or in consultation with the medical monitor.

Who cannot join

  • Subject has had any of the of the following within the 12-month period preceding trial entry: History of pseudo or psychogenic seizures, cluster seizures where the individual seizures cannot be counted, an episode of convulsive status epilepticus requiring hospitalization and intubation, or subject only has focal seizures with awareness that do not have motor activity.
  • Planned epilepsy surgery during the course of the clinical trial.
  • History of neurosurgery for seizures <1 year prior to enrollment, or radiosurgery <2 years prior to enrollment or vagus nerve stimulation (VNS) implantation.
  • History of schizophrenia, obsessive-compulsive disorder, or other serious mental health disorders.
  • History of malignancy, myeloproliferative or lymphoproliferative disorders within the past 5 years are excluded.
  • History of cardiac disease(s)/cardiac conduction disorders/or cardiac structural abnormality(ies).
Show all 9Show fewer
  • Has a positive test result or a known history of a positive test result for human immunodeficiency virus (HIV), hepatitis B surface antigen (HBsAg), or anti-hepatitis C virus (HCV) antibody at Screening.
  • Is pregnant or is breastfeeding at the time of Screening or has a positive serum pregnancy test at Screening or is planning to become pregnant during the clinical trial or within 14 days of the last study drug dose.
  • Has received any other experimental or investigational drug, device or other therapy within 30 days or 5 half-lives (whichever is longer) prior to Screening, or any prior use of gene therapy.

Trial locations and contacts

69 sites in 7 countries.

69 sites in 7 countries

United States31 sites

  • Praxis Research Site

    Amherst, New York, 14226

  • Praxis Research Site

    Bethesda, Maryland, 20817

  • Praxis Research Site

    Boston, Massachusetts, 02131

  • Praxis Research Site

    Canton, Ohio, 44718

  • Praxis Research Site

    Charlotte, North Carolina, 28211

  • Praxis Research Site

    Chesterfield, Missouri, 63005

  • Praxis Research Site

    Chicago, Illinois, 60640

  • Praxis Research Site

    Dallas, Texas, 75206

  • Praxis Research Site

    DeLand, Florida, 32720

  • Praxis Research Site

    El Paso, Texas, 79912

  • Praxis Research Site

    Frisco, Texas, 75034

  • Praxis Research Site

    Hackensack, New Jersey, 07601

  • Praxis Research Site

    Lafayette, Louisiana, 70508

  • Praxis Research Site

    Loma Linda, California, 92345

  • Praxis Research Site

    Memphis, Tennessee, 38104

  • Praxis Research Site

    Miami, Florida, 33133

  • Praxis Research Site

    Miami Lakes, Florida, 33016

  • Praxis Research Site

    Middletown, New York, 10940

  • Praxis Research Site

    Naples, Florida, 34116

  • Praxis Research Site

    New York, New York, 10016

  • Praxis Research Site

    Oklahoma City, Oklahoma, 73112

  • Praxis Research Site

    Orlando, Florida, 32825

  • Praxis Research Site

    Ozark, Missouri, 65721

  • Praxis Research Site

    Philadelphia, Pennsylvania, 19107

  • Praxis Research Site

    Phoenix, Arizona, 85032

  • Praxis Research Site

    Plymouth, Michigan, 48170

  • Praxis Research Site

    Round Rock, Texas, 78681

  • Praxis Research Site

    Seabrook, Texas, 77586

  • Praxis Research Site

    Sioux Falls, South Dakota, 57105

  • Praxis Research Site

    Virginia Beach, Virginia, 23456

  • Praxis Research Site

    Waxahachie, Texas, 75165

Other trials in United States

Spain11 sites

  • Praxis Research Site

    Barcelona, 08003

  • Praxis Research Site

    Barcelona, 08035

  • Praxis Research Site

    Barcelona, 08041

  • Praxis Research Site

    Granda, 18012

  • Praxis Research Site

    Madrid, 28006

  • Praxis Research Site

    Madrid, 28010

  • Praxis Research Site

    Madrid, 28040

  • Praxis Research Site

    Málaga, 29010

  • Praxis Research Site

    Terrassa, 08222

  • Praxis Research Site

    Valencia, 46026

  • Praxis Research Site

    Valladolid, Valladolid

Other trials in Spain

Brazil10 sites

  • Praxis Research Site

    Belo Horizonte, Minas Gerais

  • Praxis Research Site

    Botucatu, São Paulo

  • Praxis Research Site

    Campinas, São Paulo

  • Praxis Research Site

    Campo Comprido, Curitiba PR

  • Praxis Research Site

    Porto Alegre, Rio Grande do Sul

  • Praxis Research Site

    Recife, Pernambuco

  • Praxis Research Site

    Ribeirão Preto, São Paulo

  • Praxis Research Site

    Rio de Janeiro, Rio de Janeiro

  • Praxis Research Site

    São José do Rio Preto, São Paulo

  • Praxis Research Site

    São Paulo, São Paulo

Other trials in Brazil

Italy10 sites

  • Praxis Research Site

    Bologna

  • Praxis Research Site

    Lecco

  • Praxis Research Site

    Milan

  • Praxis Research Site

    Monserrato

  • Praxis Research Site

    Naples

  • Praxis Research Site

    Pavia

  • Praxis Research Site

    Pisa

  • Praxis Research Site

    Ponderano

  • Praxis Research Site

    Pozzilli

  • Praxis Research Site

    Roma

Other trials in Italy

Poland4 sites

  • Praxis Research Site

    Bydgoszcz

  • Praxis Research Site

    Katowice

  • Praxis Research Site

    Lublin

  • Praxis Research Site

    Warsaw

Other trials in Poland

Canada2 sites

  • Praxis Research Site

    Surrey, British Columbia

  • Praxis Research Site

    Toronto, Ontario

Other trials in Canada

Mexico1 site

  • Praxis Research Site

    San Lucas Tepetlacalco

Other trials in Mexico

About this study

Official title: A Double-Blind, Randomized, Multicenter, Trial Evaluating the Efficacy and Safety of PRAX-628 in Adults With Focal Seizures (POWER1)

A Double-Blind, Randomized, Multicenter, Trial Evaluating the Efficacy and Safety of PRAX-628 in Adults With Focal Seizures (POWER1)

Read the detailed description

PRAX-628-321 (POWER1) is a double-blind, randomized, multicenter, trial to evaluate the efficacy and safety of PRAX-628 in adults who can attest to concurrently taking at least 1, but no more than 3 acceptable anti-seizure medications.

Conditions
Focal Seizure
Being tested
20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeks, Placebo
Keywords
Focal Seizure
Medical subject headings
Seizures

What participants receive

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

  • 20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeksDrug

    Once daily oral

  • PlaceboDrug

    Once daily oral

Study groups in NCT06999902
Study groupRoleWhat they receive
Randomized, Double-Blind 20mg/day for 6 weeks then 30mg/day for remaining 6 weeks PRAX-628ExperimentalParticipants who meet all eligibility criteria will be randomized at Visit 1 (Day 1) to receive 20 mg of PRAX-628 for 6 weeks followed by 30 mg PRAX 628 for the remaining 6 weeks.
Receives: Drug: 20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeks
Randomized, Double-Blind PlaceboExperimentalParticipants who meet all eligibility criteria will be randomized at Visit 1 (Day 1) to receive a matching placebo throughout the 12-week Treatment Period
Receives: Drug: Placebo

What is being measured

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

  1. To evaluate the efficacy of PRAX-628 compared to placebo on focal seizure frequency in adults currently taking 1 to 3 ASMs

    Median percent change in monthly (28 days) focal seizure frequency from the Screening/Observation Period to the Treatment Period for PRAX-628 compared to placebo.

    Measured: 12 weeks

Secondary outcomes (11)

  1. To evaluate the efficacy of PRAX 628 compared to placebo on focal seizure frequency in adults currently taking 1 to 3 ASMs

    Proportion of participants experiencing a ≥50% reduction in monthly (28 days) focal seizure frequency from the Screening/Observation Period to the Treatment Period (Responder Rate) for PRAX 628 compared to placebo.

    Measured: 12 weeks

  2. To assess trends over time in efficacy of PRAX 628 on focal seizure frequency

    Percent change in monthly focal seizure frequency from the Screening/Observation Period to the Treatment Period for PRAX-628 compared with placebo.

    Measured: 12 weeks

  3. To evaluate the efficacy of PRAX 628 compared to placebo on focal seizure frequency in adults currently taking 1 to 3 ASMs

    Number of days post-randomization to reach the same number of monthly focal seizures as the Screening/Observation Period through the end of the Treatment Period

    Proportion of participants experiencing seizure freedom, 100% reduction in monthly (28 days) focal seizure frequency from the Screening/Observation Period to the Treatment Period for PRAX-628 compared with placebo

    Impact of PRAX-628 compared to placebo on PGI-S and CGI-S

    Measured: 12 weeks

  4. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Incidence and severity of TEAEs, including discontinuation of study drug due to TEAEs

    Measured: 12 weeks

  5. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Change in tympanic temperature in Celsius

    Measured: 12 weeks

  6. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Change in heart rate in beats per minute

    Measured: 12 weeks

  7. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Change in blood pressure in mm/Hg

    Measured: 12 weeks

  8. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Change in respiratory rate in breaths per minute

    Measured: 12 weeks

  9. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    The principal investigator (PI) or sub investigator will review the laboratory report and document this review. Any clinically significant adverse changes occurring during the clinical trial will be documented as adverse events.

    Measured: 12 weeks

  10. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Incidence of clinically significant ECG abnormalities

    Measured: 12 weeks

  11. To assess the safety and tolerability of PRAX-628 in adults with focal seizures

    Changes in suicidality, as assessed by C-SSRS

    Measured: 12 weeks

Timeline

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

  1. First posted31 May 2025
  2. Study start11 Dec 2024
  3. Primary completion14 May 2026
  4. Study completion14 May 2026

Resources

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 2/3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
255 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06999902
Sponsor's protocol ID
PRAX-628-321
Acronym
POWER1
Status last verified
Aug 2026
First submitted
14 Mar 2025
Last updated
10 Aug 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing 20mg/day PRAX-628 for 6 weeks then 30mg/day PRAX-628 for remaining 6 weeks in people with Focal Seizure, run by Praxis Precision Medicines at 69 sites in 7 countries.

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 2 inclusion and 9 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 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 69 sites in United States, Spain, Brazil, Italy, Poland and 2 more countries. 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 combined phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

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

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

To evaluate the efficacy of PRAX-628 compared to placebo on focal seizure frequency in adults currently taking 1 to 3 ASMs (time frame: 12 weeks). 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 NCT06999902.

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 Aug 2026.

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