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Ataxia-TelangiectasiaPhase 3NCT06673056

A Pivotal Study of N-Acetyl-L-Leucine on Ataxia-Telangiectasia (A-T)

A Phase 3 study testing N-Acetyl-L-Leucine in people with Ataxia-Telangiectasia and Ataxia-Telangiectasia (A-T), run by IntraBio Inc at 11 sites in 6 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

A pivotal, randomized, double-blind, placebo-controlled, multi-center therapeutic study for patients age 4 and older with a confirmed diagnosis of Ataxia-Telangiectasia (A-T). The objective of this study is to evaluate the safety, tolerability and efficacy of N-acetyl-L-leucine (IB1001) compared to standard of care. Read more about this study

Who is it for?
Ages 4 years and older
What is being tested?
N-Acetyl-L-Leucine
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
60 participants
Where
11 sitesin 6 countries
Study dates
18 Mar 2025to 1 Jun 2028
Phase
Phase 3
Are there results?
Not yet: the study is under way

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 4 years and older
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Who may be able to join

  • 1. Written informed consent signed by the patient and/or their legal representative / parent/ impartial witness 2. Male or female aged ≥4 years with a genetically confirmed diagnosis of A-T at the time of signing informed consent.
  • 3. Females of childbearing potential, defined as a premenopausal female capable of becoming pregnant, will be included if they are either sexually inactive (sexually abstinent for 14 days prior to the first dose and confirm to continue through 28 days after the last dose) or using one of the following highly effective contraceptives (i.e. results in <1% failure rate when used consistently and correctly) 14 days prior to the first dose continuing through 28 days after the last dose:
  • intrauterine device (IUD);
  • surgical sterilization of the partner (vasectomy for 6 months minimum);
  • combined (estrogen or progestogen containing) hormonal contraception associated with the inhibition of ovulation (either oral, intravaginal, or transdermal);
  • progestogen only hormonal contraception associated with the inhibition of ovulation (either oral, injectable, or implantable);
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  • intrauterine hormone releasing system (IUS);
  • bilateral tubal occlusion. 4. Females of non-childbearing potential who have undergone one of the following sterilization procedures at least 6 months prior to the first dose:
  • <!-- -->
  • hysteroscopic sterilization;
  • bilateral salpingectomy;
  • hysterectomy;
  • bilateral oophorectomy; OR be postmenopausal with amenorrhea for at least 1 year prior to the first dose and follicle stimulating hormone (FSH) serum levels consistent with postmenopausal status. FSH analysis for postmenopausal women will be done at screening. FSH levels should be in the postmenopausal range as determined by the central laboratory.
  • 5. Non-vasectomized male patient agrees to use a condom with spermicide during the study until 90 days beyond the last dose of study medication and the female partner agrees to comply with inclusion criteria 3 or 4. For a vasectomized male who has had his vasectomy 6 months or more prior to study start, it is required that they use a condom during sexual intercourse. A male who has been vasectomized less than 6 months prior to study start must follow the same restrictions as a non-vasectomized male.
  • 6. If male, patient agrees not to donate sperm from the first dose until 90 days after their last dose.
  • 7. Patients must fall within:
  • <!-- -->
  • A SARA score of 7 ≤ X ≤ 34 points (out of 40) AND
  • Either:
  • Within the 2-7 range (0-8 range) of the Gait subtest of the SARA scale OR ii. Be able to perform the 9-Hole Peg Test with Dominant Hand (9HPT-D) (SCAFI subtest) in 20 ≤ X ≤150 seconds.
  • 8. Weight ≥15 kg at screening. 9. Patients are willing to disclose their existing medications/therapies for (the symptoms) of A-T, including those on the prohibited medication list. Non-prohibited medications/therapies, therapy, and physiotherapy) are permitted provided:
  • The Investigator does not believe the medication/therapy will interfere with the study protocol/results
  • Patients have been on a stable dose/duration and type of therapy for at least 42 days before Visit 1 (Baseline 1)
  • Patients are willing to maintain a stable dose/do not change their therapy throughout the duration of the study.
  • 10. An understanding of the implications of study participation, provided in the written patient information and informed consent by patients or their legal representative/parent, and demonstrates a willingness to comply with instructions and attend required study visits (for children this criterion will also be assessed in parents or appointed guardians).

Who cannot join

  • 1. Patients who have any known hypersensitivity or history of hypersensitivity to:
  • Acetyl-Leucine (DL-, L-, D-) or derivatives.
  • Excipients the IB1001 sachet (namely isomalt, hypromellose, and strawberry flavor).
  • Excipients the placebo sachet (namely isomalt, hypromellose, strawberry flavor, citric acid, microcrystalline cellulose, lactose, denatonium benzoate).
  • 2. Simultaneous participation in another clinical study or participation in any clinical study involving administration of an investigational medicinal product (IMP; 'study drug') for at least 42 days prior to Visit 1. At the discretion of the investigator, Medical Monitor, and Sponsor, the washout period for specific IMPs may be longer based on the pharmacological activity and pharmacokinetics of the drug.
  • 3. Patients with a physical or psychiatric condition which, at the investigator's discretion and in consultation with the Medical Monitor and Sponsor (as applicable), may put the patient at risk, may confound the study results, or may interfere with the patient's participation in the clinical study, i.e. reliably perform study assessments.
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  • 4. Known or persistent use, misuse, or dependency of medication, drugs, or alcohol.
  • 5. Current or planned pregnancy or women who are breastfeeding. 6. Patients with severe vision or hearing impairment (that is not corrected by glasses or hearing aids) that, at the investigator's discretion, interferes with their ability to perform study assessments.
  • 7. Patients who have been diagnosed with arthritis or other musculoskeletal disorders affecting joints, muscles, ligaments, and/or nerves that by themselves affects patient's mobility and, at the investigator's discretion, interferes with their ability to perform study assessments.
  • 8. Patients unwilling and/or not able to undergo a 42-day washout period from any of the following prohibited medication prior to Visit 1 (Baseline 1) and remain without prohibited medication through Visit 6.
  • <!-- -->
  • N-Acetyl-DL-Leucine (e.g. Tanganil®);
  • N-Acetyl-L-Leucine (prohibited if not provided as IMP in the IB1001-303 trial);
  • Sulfasalazine;
  • Rosuvastatin.

Trial locations and contacts

11 sites in 6 countries.

11 sites in 6 countries

United States3 sites

  • Massachusetts General Hospital

    Boston, Massachusetts, 02114

  • The University of Texas Health (UT Health)

    Houston, Texas, 77030

  • University of California Los Angeles

    Los Angeles, California, 90095

Other trials in United States

Germany2 sites

  • University of Cologne

    Cologne, 50937

  • University of Giessen

    Giessen, 35392

Other trials in Germany

Slovakia2 sites

  • Comenius University Bratislava

    Bratislava, 814 99

  • University Hospital L. Pasteur

    Košice, 040 11

Other trials in Slovakia

United Kingdom2 sites

  • Royal Papworth Hospital

    Cambridge

  • University of Nottingham

    Nottingham

Other trials in United Kingdom

Spain1 site

  • Hospital Universitario La Paz

    Madrid, 28046

Other trials in Spain

Switzerland1 site

  • University of Bern

    Bern, 3012

Other trials in Switzerland

About this study

Official title: Effects of N-Acetyl-L-Leucine on Ataxia-Telangiectasia (A-T: A Phase III, Randomized, Placebo-controlled, Double-blind, Crossover Study

A pivotal, randomized, double-blind, placebo-controlled, multi-center therapeutic study for patients age 4 and older with a confirmed diagnosis of Ataxia-Telangiectasia (A-T). The objective of this study is to evaluate the safety, tolerability and efficacy of N-acetyl-L-leucine (IB1001) compared to standard of care.

Read the detailed description

This is a multinational, randomized, placebo-controlled, double-blinded, cross-over Phase III study that will assess the safety and efficacy of N-Acetyl-L-Leucine (IB1001) versus Placebo for the treatment of Ataxia-Telangiectasia (A-T).

Patients will be assessed during three study periods: a baseline period (approximately 2-weeks), after which they will be randomized (1:1) to receive treatment with IB1001 or Placebo for approximately 12-weeks during the first intervention period ("Period I"). Following Period I, patients will crossover to receive the opposite treatment (IB1001 or Placebo) for approximately 12-weeks during a second intervention period ("Period II).

Patients will be assessed twice during each study period. Patients who have participated in the study may be offered the opportunity to roll over into an Extension Phase, which is planned to allow patients to have further access to IB1001.

Being tested
N-Acetyl-L-Leucine, Placebo
Keywords
Ataxia-Telangiectasia, Louis Bar Syndrome
Medical subject headings
Ataxia Telangiectasia

What participants receive

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

  • N-Acetyl-L-LeucineDrug

    Also called IB1001, levacetylleucine

    N-Acetyl-L-Leucine is a modified amino-acid ester that is orally administered (granules for suspension in a sachet)

  • PlaceboOther

    Matching Placebo Sachet

Study groups in NCT06673056
Study groupRoleWhat they receive
N-acetyl-L-leucine (IB1001)ExperimentalOral administration (granule in a sachet for suspension in water, orange juice, or almond milk). Patients will receive a total daily dose of 2-4 g/day based on weight-tiered doses.
Receives: Drug: N-Acetyl-L-Leucine
Placebo comparatorPlacebo comparatorOral administration (granule in a sachet for suspension in water, orange juice, or almond milk). Patients will receive a total daily dose of 2-4 g/day based on weight-tiered doses.
Receives: Other: Placebo

What is being measured

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

  1. Scale for the Assessment and Rating of Ataxia

    The Scale for Assessment and Rating of Ataxia has 8 items that are related to gait, stance, sitting, speech, finger-chase test, nose-finger test, fast alternating movements, and heel-shin test. The range is 0-40 points, with a lower score representing neurological improvement and a higher score representing neurological worsening.

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

Secondary outcomes (5)

  1. Spinocerebellar Ataxia Functional Index (SCAFI)

    Spinocerebellar Ataxia Functional Index (SCAFI) is composed of 8 Meter Walk Test, 9-Hole Peg Test of Dominant and Non-Dominant Hand (9HPT-D/9HPT-ND) (the 3 tests are timed assessments; each is done twice and values are averaged; the 8MWT and 9HPT-D and 9HPT-ND values are converted from times to rates, and the results expressed as a composite Z-score of each test relative to baseline) and the PATA rate (counted number how often a patient can repeat the syllables "PATA" within 10 seconds), a measure of speech performance. The scores of these 3 were transformed to Z-scores (=individual's average of both trials to perform the respective task - mean of study population at baseline) / SD of study population at baseline). A Z-score of 0 equates to the population mean at baseline. For all 3, higher Z-scores (above mean) mean better performance. The SCAFI total score was calculated as the arithmetic mean of the non-missing Z-scores for the 3. A higher total score means better performance.

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

  2. Physician's / Caregiver's / Patient's Clinical Global Impressions (CGI)

    The Clinical Global Impression of Improvement assessed by the investigator/caregiver/patient is evaluated on a 7 point Likert scale ranging from 1='very much improved' to 7='very much worse'

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

  3. EuroQuol- 5 Dimension (EQ-5D) Quality of Life Scale

    For posting, health-related quality of life based on the EQ-5D visual analogue scale (VAS) was presented as a secondary endpoint.

    EQ-5D VAS is a 0-100 scale where patients are asked to indicate their overall health, with a score of 0 indicating worst health and a score of 100 indicating best health.

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

  4. International Cooperate Ataxia Rating Scale (ICARS)

    The International Cooperate Ataxia Rating Scale (ICARS) was developed to quantify the level of impairment as a result of ataxia as related to hereditary ataxias. Disorders rated as subscales within the ICARS are: Postural and gait disturbances, Limb Ataxia, Dysarthria, and Oculomotor disorders

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

  5. Neuro Quality of Life - Upper Extremity Function (NeuroQOL-UEF)

    The Neurology Quality of Life (NeuroQOL) Upper Extremity Function (UEF) scale is a self-report of health-related quality of life that measures the patient's ability to carry out various activities involving digital, manual, and reach-related functions, ranging from fine motor to self-care (activities of daily living)

    Measured: End of Period I (week 12) vs. End of Period 2 (week 24)

Timeline

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

  1. First posted4 Nov 2024
  2. Study start18 Mar 2025
  3. Primary completion31 Dec 2027 (estimated)
  4. Study completion1 Jun 2028 (estimated)

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 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Crossover
Model description
Randomized, placebo-controlled, double-blind, crossover, multi-center, study with 1:1 randomization of IB1001 plus SOC for 12-weeks versus placebo plus SOC for 12-weeks, followed by open-label extension study.
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
60 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06673056
Sponsor's protocol ID
IB1001-303
Status last verified
Nov 2026
First submitted
31 Oct 2024
Last updated
4 Nov 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: The results of the study will be published within a reasonable timeframe of completion. Pseudonymised individual patient data may be available in these findings.

Publications

  • Martakis K, Bremova-Ertl T, Bolton C, Foltan T, Del Mar Garcia Romero M, Gautschi M, Han V, Hahn A, Kolnikova M, Panagioti O, Perlman S, Prasad M, Schmahmann J, Skorvanek M, Thakur N, Thiel M, Hoche F. Safety and efficacy of levacetylleucine in ataxia-telangiectasia: a phase 3, randomised, double-blind, placebo-controlled crossover trial. Lancet Neurol. 2026 Jul;25(7):633-644. doi: 10.1016/S1474-4422(26)00158-4.

    PubMed 42309084

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing N-Acetyl-L-Leucine in people with Ataxia-Telangiectasia and Ataxia-Telangiectasia (A-T), run by IntraBio Inc at 11 sites in 6 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 25 inclusion and 15 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: under way, not looking for participants, as of the sponsor's last update on 4 Nov 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, Germany, Slovakia, United Kingdom, Spain and 1 more country. 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 phase mean?

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?

This study is still under way. Results are not available in the source record yet.

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?

Scale for the Assessment and Rating of Ataxia (time frame: End of Period I (week 12) vs. End of Period 2 (week 24)). 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 NCT06673056, 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 4 Nov 2026.

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