Myotonic Dystrophy 1Phase 1/2ArthemiRNCT06300307
Study of ATX-01 in Participants With DM1
A Phase 1/2 study testing ATX-01 in people with Myotonic Dystrophy 1, run by ARTHEx Biotech S.L. at 12 sites in 7 countries.
Trial summary
The goal of this clinical trial is to test ATX-01 in participants with myotonic dystrophy type 1 (DM1). The main question it aims to answer is if ATX-01 is safe and well tolerated. The trial will compare the safety and tolerability of ATX-01 and a matching placebo. Read more about this study
- Who is it for?
- Ages 18 to 64 years
- Conditions the study is for
- Myotonic Dystrophy 1
- What is being tested?
- ATX-01
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 56 participants
- Where
- 12 sitesin 7 countries
- Study dates
- 15 Oct 2024to Jul 2027
- Phase
- Phase 1/2
- 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 18 to 64 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Participants with a documented clinical diagnosis of DM1 (CTG expansion of >150 repeats in DMPK gene measured in peripheral blood mononuclear cells)
- Ambulatory, defined as able to complete a 10-meter walk/run test at screening without the use of assistive devices such as canes, walkers, or orthoses, except for ankle-foot orthoses
- Presence for >3 seconds of grip myotonia as confirmed by a central reader
Who cannot join
- Participants with congenital DM1
- Medical Research Council Muscle Scale score of less than 4 on ankle dorsiflexion or significant tibialis anterior atrophy that prevents a muscle biopsy
- Use of mexiletine or other agent for myotonia within 21 days or 5 half-lives, whichever is longer, prior to screening
Trial locations and contacts
12 sites in 7 countries. Contact the study team or a site near you to ask about taking part.
12 sites in 7 countries
United States5 sites, 5 recruiting
- Recruiting
University of Kansas Medical Center, Department of Neurology
Fairway, Kansas, 66205
Cassidy Nelson, 913-588-3653, cnelson15@kumc.edu
- Recruiting
University of Florida
Gainesville, Florida, 32610
Brandy Donahue-Quails, Brandy.Donahue-Quails@neurology.ufl.edu
- Recruiting
University of Iowa Health Care - Department of Neurology
Iowa City, Iowa, 52242
Heena Olalde, 319-356-8326, heena-olalde@uiowa.edu
Andrea Swenson
- Recruiting
UCLA
Los Angeles, California, 90095
Michael Yan, 310-825-3264, MYan@mednet.ucla.edu
Perry Shieh, MD, PhD
- Recruiting
Virginia Commonwealth University
Richmond, Virginia, 23298
Jodie Howell, 804-828-6110, jodie.howell@vcuhealth.org
Nicholas Johnson, MD
Italy2 sites, 2 recruiting
- Recruiting
The NeMO Clinical Center in Milan, Neurorehabilitation Unit, University of Milan
Milan, 20162
Clinical Research Co-ordinator, crc_rsu@centrocliniconemo.it
- Recruiting
Fondazione Policlinico A. Gemelli- IRCCS
Rome, 00168
Professor, marika.pane@policlinicogemelli.it
Canada1 site, 1 recruiting
- Recruiting
Centre Intégré Universitaire de Santé et Services Sociaux du Saguenay-Lac-St-Jean
Chicoutimi, Quebec, G7H 5H6
Sabrina Côté, 418-541-1000 ext. 3065, sabrina.cote.inf@ssss.gouv.qc.ca
France1 site, 1 recruiting
- Recruiting
Institute of Myology
Paris, 75651
Study Co-ordinator, essais-adultes@institut-myologie.org
Netherlands1 site, 1 recruiting
- Recruiting
Radboudumc
Nijmegen, 6525
Spierziekten Research Team Radboudumc, spierziektenresearchteam@radboudumc.nl
K Mul
Spain1 site, 1 recruiting
- Recruiting
Hospital Universitario Donostia
Donostia / San Sebastian, 20014
Ioana Croitoru, IOANA.CROITORU@bio-gipuzkoa.eus
Adolfo López de Munain Arregui
United Kingdom1 site, 1 recruiting
- Recruiting
St. George's University Hospital
London, SW17 0RE
Joana Teixeira, Joana.Teixeira@stgeorges.nhs.uk
Emma Matthews
About this study
Official title: A Phase 1/2a Double-Blind, Placebo-controlled, Single- and Multiple Ascending Dose Study to Assess the Safety, Tolerability, PK, PD and Efficacy of IV Administration of ATX-01 In Male and Female Participants Aged 18 to 64 With Classic DM1
The goal of this clinical trial is to test ATX-01 in participants with myotonic dystrophy type 1 (DM1). The main question it aims to answer is if ATX-01 is safe and well tolerated. The trial will compare the safety and tolerability of ATX-01 and a matching placebo.
There will be a single-ascending dose part of the trial and a multiple-ascending dose part. In the single-ascending dose, participants will receive one dose of ATX-01 or placebo. In the multiple-ascending dose part, participants will receive three doses of ATX-01 or placebo.
ATX-01 is a novel anti-miR (synthetic single stranded oligonucleotide) that inhibits a microRNA called miR-23b.
- Conditions
- Myotonic Dystrophy 1
- Being tested
- ATX-01, Placebo
- Medical subject headings
- Myotonic Dystrophy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ATX-01Drug
Solution for infusion
PlaceboDrug
Solution for infusion
| Study group | Role | What they receive |
|---|---|---|
| ATX-01 | Experimental | ATX-01 is a formulation of the anti-microRNA 23b (anti-miR-23b), known as X82108, a novel type of antisense oligonucleotide Receives: Drug: ATX-01 |
| Placebo | Placebo comparator | Placebo to ATX-01 Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of adverse events
To evaluate the safety and tolerability of ATX-01 in adult participants with DM1
Measured: Up to 120 days
Secondary outcomes (6)
Incidence of clinically significant changes in laboratory assessments, electrocardiograms (ECGs), vital signs, suicidal ideation and behavior
To further evaluate the safety and tolerability of ATX-01 in adult participants with DM1
Measured: Up to 120 days
Maximum observed plasma concentration (Cmax) of ATX-01
Measured: Up to 48 hours post-dose
Area under the plasma concentration-time curve (AUC) of ATX-01
Measured: Up to 48 hours post-dose
Video hand opening time
To evaluate the efficacy of ATX-01 on myotonia in participants with DM1
Measured: Change from baseline up to 120 days
Change from baseline in ankle dorsiflexion strength by quantitative myometry
To evaluate the effects of ATX-01 in participants with DM1 on ankle dorsiflexion strength
Measured: Change from baseline up to 120 days
Change from baseline in Impact on Activities of Daily Living questionnaire item scores
The Impact on Activities of Daily Living questionnaire is a 7-item patient-reported outcome designed to evaluate the impact of ATX-01 on activities of daily living in participants with DM1.
Measured: Change from baseline up to 120 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Mar 2024
- Study start15 Oct 2024
- Primary completionJul 2027 (estimated)
- Study completionJul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Myotonic Dystrophy 1Studies of the same condition, open and under way.
- 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
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 56 participants (estimated)
Sponsor and investigators
- Lead sponsor
- ARTHEx Biotech S.L.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06300307
- Sponsor's protocol ID
- CT-ATX-01-DM1-1.1
- Acronym
- ArthemiR
- Status last verified
- Feb 2026
- First submitted
- 26 Feb 2024
- Last updated
- 10 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 10 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1/2a Double-Blind, Placebo-controlled, Single- and Multiple Ascending Dose Study to Assess the Safety, Tolerability, PK, PD and Efficacy of IV Administration of ATX-01 In Male and Female Participants Aged 18 to 64 With Classic DM1
- ClinicalTrials.gov ID
- NCT06300307
- Acronym / sponsor ID
- ArthemiR / CT-ATX-01-DM1-1.1
- Conditions
- Myotonic Dystrophy 1
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 56 participants (estimated)
- Lead sponsor
- ARTHEx Biotech S.L.Industry (pharma, biotech, devices)
- Study start
- 15 Oct 2024 (actual)
- Primary completion
- Jul 2027 (estimated)
- Study completion
- Jul 2027 (estimated)
- First posted
- 8 Mar 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to test ATX-01 in participants with myotonic dystrophy type 1 (DM1). The main question it aims to answer is if ATX-01 is safe and well tolerated. The trial will compare the safety and tolerability of ATX-01 and a matching placebo.
There will be a single-ascending dose part of the trial and a multiple-ascending dose part. In the single-ascending dose, participants will receive one dose of ATX-01 or placebo. In the multiple-ascending dose part, participants will receive three doses of ATX-01 or placebo.
ATX-01 is a novel anti-miR (synthetic single stranded oligonucleotide) that inhibits a microRNA called miR-23b.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| ATX-01 | Experimental | Drug: ATX-01ATX-01 is a formulation of the anti-microRNA 23b (anti-miR-23b), known as X82108, a novel type of antisense oligonucleotide |
| Placebo | Placebo comparator | Drug: PlaceboPlacebo to ATX-01 |
Who may qualify
- Ages
- 18 to 64 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Participants with a documented clinical diagnosis of DM1 (CTG expansion of >150 repeats in DMPK gene measured in peripheral blood mononuclear cells)
- Ambulatory, defined as able to complete a 10-meter walk/run test at screening without the use of assistive devices such as canes, walkers, or orthoses, except for ankle-foot orthoses
- Presence for >3 seconds of grip myotonia as confirmed by a central reader
Key exclusion criteria (3 listed)
- Participants with congenital DM1
- Medical Research Council Muscle Scale score of less than 4 on ankle dorsiflexion or significant tibialis anterior atrophy that prevents a muscle biopsy
- Use of mexiletine or other agent for myotonia within 21 days or 5 half-lives, whichever is longer, prior to screening
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 |
|---|---|---|
| ATX-01Solution for infusion | Drug | ATX-01 |
| PlaceboSolution for infusion | Drug | Placebo |
Primary outcome
Incidence of adverse events
Time frame: Up to 120 days
To evaluate the safety and tolerability of ATX-01 in adult participants with DM1
6 secondary outcomes
Incidence of clinically significant changes in laboratory assessments, electrocardiograms (ECGs), vital signs, suicidal ideation and behavior
Time frame: Up to 120 days
Maximum observed plasma concentration (Cmax) of ATX-01
Time frame: Up to 48 hours post-dose
Area under the plasma concentration-time curve (AUC) of ATX-01
Time frame: Up to 48 hours post-dose
Video hand opening time
Time frame: Change from baseline up to 120 days
Change from baseline in ankle dorsiflexion strength by quantitative myometry
Time frame: Change from baseline up to 120 days
Change from baseline in Impact on Activities of Daily Living questionnaire item scores
Time frame: Change from baseline up to 120 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Feb 2026.
- Individual participant dataSharing planned: Undecided
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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.
12 sites in 7 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing ATX-01 in people with Myotonic Dystrophy 1, run by ARTHEx Biotech S.L. at 12 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 3 inclusion and 3 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: looking for participants now, as of the sponsor's last update on 10 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 12 sites in United States, Italy, Canada, France, Netherlands 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. 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?
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?
Contact Project Manager (+34676229821, clinical@arthexbiotech.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of adverse events (time frame: Up to 120 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 Feb 2026.