X-Linked Myotubular MyopathyPhase 1/2NCT07052929
Study of ASP2957 in Male Participants With X-linked Myotubular Myopathy Who Need Ventilators
A Phase 1/2 study testing ASP2957, Methylprednisolone and Prednisolone in people with X-Linked Myotubular Myopathy, run by Astellas Gene Therapies at 5 sites in 2 countries.
Trial summary
X-linked myotubular myopathy (XLMTM) is a rare and serious condition present at birth where the muscles do not work properly. There are currently no approved therapies for XLMTM. The protein myotubularin is needed for muscle development, movement and breathing. A gene called MTM1 tells the body to make myotubularin. Read more about this study
- Who is it for?
- Ages Up to 36 months, men only
- Conditions the study is for
- X-Linked Myotubular Myopathy
- What is being tested?
- ASP2957, Methylprednisolone and Prednisolone
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 9 participants
- Where
- 5 sitesin 2 countries
- Study dates
- 15 Dec 2025to 31 Oct 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 Up to 36 months
- Men only
- No healthy volunteers
- Child
Who may be able to join
- Participant is projected to be ≤ 36 months of age at dosing.
- Participant has molecular genetic report from a CAP-approved testing facility at screening that confirms a diagnosis of XLMTM and harbors a "pathogenic" or "likely pathogenic" variant in the MTM1 gene as classified using the American College of Medical Genetics (ACMG) standards and guidelines for interpretation of sequence variants. Although samples will be sent to the sponsor central laboratory during screening for exploratory testing, results of this testing are not required for enrollment.
- Participant is ventilator-dependent and meets the following criteria:
- Required respiratory support at birth
- Requires ≥ 20 hours per day of invasive ventilator support (confirmed during screening)
- Has a tracheostomy tube
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- Participant has no evidence of hepatic peliosis, increased echogenicity or any other clinically important abnormal finding on liver ultrasound.
- Participant can receive immunosuppression per protocol.
- Participant's hepatobiliary laboratory measurements must meet the criteria during screening and for the 2-month retrospective assessment of participant's medical history from the time of signing the ICF:
- Participant's hematological laboratory measurements must meet the criteria during screening:
- Participant's parent(s) or legally authorized representative LAR(s) must provide documentation of being current with recommended immunization schedule according to regional guidelines.
- If any immunization has not been administered, the medical reasons must be documented by the investigator along with medical risk associated with ASP2957 and immunosuppression administration. The sponsor will review the risk assessment with the investigator and determine the participant's eligibility for the study.
- Immunizations requiring administration after inclusion in the study must be administered in accordance with regional guidelines for live, live attenuated and inactivated immunization prior to, during and after stopping immunosuppression with methylprednisolone, prednisolone and sirolimus. For an example of guidelines, see Centers for Disease Control and Prevention (CDC) General Best Practices Guidelines for Immunization.
- Immunization of household contacts can be considered based on regional standards of care of individuals receiving immunosuppression regimens.
- Participant and participant's parent(s) or LAR(s) are willing and able to comply with study visits and study procedures.
- Participant's parent(s) or LAR(s) agree that the participant will not participate in another interventional study from the time of signing the Informed Consent Form (ICF) through week 52.
- Participant's parent(s) or LAR(s) is willing to transition the participant to a separate long-term follow-up study after study completion.
Who cannot join
- Participant born < 35 weeks gestation is still not term as per corrected age.
- Participant is nutritionally unstable with weight less than fifth percentile for age or has a vitamin A, E or K deficiency.
- Participant requires supplemental oxygen on a routine or chronic basis.
- Note: The use of supplemental oxygen for acute, self-limited illnesses (for example, during hospitalization for pneumonia) shall not be exclusionary, provided the participant is neither acutely ill nor using supplemental oxygen at the time of screening.
- Participant currently has a clinically important respiratory infection or other clinically important active infection of any kind.
- Participant has an active viral or bacterial infection including, but not limited to, positive testing for the following:
Show all 30Show fewer
- tuberculosis (TB) using the QuantiFERON-TB test
- Active hepatitis A virus (HAV), hepatitis B virus (HBV) or hepatitis C virus (HCV)
- Prior HBV or HCV virus infection due to the risk of reactivation associated with immunosuppression
- human immunodeficiency virus type 1 (HIV-1) and human immunodeficiency virus type 2 (HIV-2)
- coronavirus disease 2019 (COVID-19)
- cytomegalovirus (CMV), viral loads ≥ 500 IU/mL or attributable symptoms or evidence of end-organ disease due to CMV.
- Participant has any history of cholestatic liver dysfunction and/or treatment for cholestasis. If the participant is taking prophylactic treatment for cholestasis (e.g., ursodiol, cholestyramine, rifampin or other therapies) which has not been prescribed for cholestatic liver dysfunction, treatment must be discontinued for at least 4 weeks prior to signing the ICF.
- Neonatal hyperbilirubinemia resolving within 4 weeks of birth in a full-term infant is not an exclusion.
- Participant has prior history of abnormal transaminases (alanine aminotransferase (ALT) or aspartate aminotransferase (AST)) and/or abnormal bilirubin metabolism associated with ascites, jaundice (aside from neonatal hyperbilirubinemia) or gastrointestinal bleeding.
- Participant has a significant medical condition or life-threatening disease other than XLMTM that would interfere with adhering to protocol requirements or would increase the risk of immunosuppression and/or recombinant adeno-associated virus (rAAV) administration.
- Participant has musculoskeletal complications such as severe contractures and/or scoliosis that would limit the ability to observe improvements in neuromuscular function.
- In participants with scoliosis, the Cobb angle must be < 40 degrees for study eligibility.
- Other than as required per protocol, participant has received or plans to receive systemic immunomodulating agents within 90 days before day 1 (use of inhaled corticosteroids to manage chronic respiratory conditions is allowed).
- Participant has previously received monoclonal antibodies of any type.
- Exception: Monoclonal antibodies to prevent RSV are permitted, except for during the 4 weeks prior to the initiation of immunosuppression.
- Participant plans to have surgery within 12 weeks prior to day 1 through week 52 that may confound safety and efficacy data interpretation of the study intervention.
- Exception: Standard of care surgical interventions such as gastrostomy, jejunostomy and Nissen fundoplication procedures are allowed.
- Participant received any treatment for cholestasis (e.g., ursodiol, cholestyramine, rifampin or other therapies) prior to signing the ICF.
- Participant is participating in another interventional study or has received an adeno-associated virus (AAV)-based gene therapy.
- Participant tests positive for anti-MyoAAV3.8 TAb, as determined by central laboratory testing.
- Since very young children may have passive antibodies transferred in utero from the mother, participants ≤ 6 months of age who initially test positive for anti-MyoAAV3.8 total antibody (TAb) may be rescreened for study eligibility.
- Participant has a known or suspected contraindication or hypersensitivity to methylprednisolone, prednisolone, sirolimus or any components of the ASP2957 formulation.
- Participant has a contraindication to general anesthesia, magnetic resonance imaging (MRI) or muscle biopsy procedures.
- Any other reason that would render the participant unsuitable for participation in the study, including risk of non-adherence to the study assessments and protocol.
Trial locations and contacts
5 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
5 sites in 2 countries
United States4 sites, 4 recruiting
- Recruiting
Boston Children's Hospital
Boston, Massachusetts, 02115
- Recruiting
Lurie Children's Hospital
Chicago, Illinois, 60611
- Recruiting
The University of Texas Southwestern Medical Center
Dallas, Texas, 75390
- Recruiting
Oregon Health & Science University
Portland, Oregon, 97239
Canada1 site, 1 recruiting
- Recruiting
The Hospital for Sick Children
Toronto, Ontario
About this study
Official title: A Phase 1/2, Multicenter, Open-label, Dose Escalation and Expansion Clinical Study to Evaluate the Safety, Tolerability and Preliminary Efficacy of ASP2957 in Male Participants With Invasive Ventilator-dependent X-linked Myotubular Myopathy
X-linked myotubular myopathy (XLMTM) is a rare and serious condition present at birth where the muscles do not work properly. There are currently no approved therapies for XLMTM.
The protein myotubularin is needed for muscle development, movement and breathing. A gene called MTM1 tells the body to make myotubularin. XLMTM is caused by changes, or mutations, in the MTM1 gene. Changes in the MTM1 gene cause low or no levels of myotubularin to be made, so the muscles do not work properly.
Read more
Gene therapy is a way of getting a healthy copy of a gene into the body. This allows the body's cells to make a normal protein that may reduce disease symptoms. Researchers have developed ASP2957 to get a healthy MTM1 gene into the body. This could help improve muscle development and function in young children with XLMTM.
In this study, ASP2957 will be given to humans for the first time.
ASP2957 has the healthy MTM1 gene inside a type of empty (killed) virus. The virus delivers the healthy MTM1 gene directly into cells in the body. It's possible that some boys may have antibodies to the virus if they have previously been infected with a similar virus. The antibodies could stop ASP2957 from working properly and cause an immune reaction to ASP2957. To prevent this, the boys will also be given medicines to lower the immune system.
The main aims of this study are to check the safety of ASP2957, how well it is tolerated, and to find a suitable dose of ASP2957.
The study was designed in 2 phases. In Phase 1, different small groups of boys will receive lower to higher doses of ASP2957. Each boy will receive a single infusion of ASP2957. Any medical problems will be recorded for each dose. This is done to find a suitable dose of ASP2957 to use in Phase 2.
In Phase 2, another small group of young boys will receive a single infusion of ASP2957. The most suitable dose of ASP2957 worked out from Phase 1 will be used.
The boys will be checked for up to 1 year after their single infusion of ASP2957. After this, there will be the option for the boys to join another study so they will continue to be checked longer term.
- Conditions
- X-Linked Myotubular Myopathy
- Being tested
- ASP2957, Methylprednisolone, Prednisolone, Sirolimus
- Keywords
- XLMTM, Recombinant Adeno-Associated Virus
- Medical subject headings
- Myopathies, Structural, Congenital
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ASP2957Genetic
Also called MyoAAV3.8 engineered capsid - myosin heavy chain kinase 7 - human myotubularin (MyoAAV3.8-MHCK7-hMTM1)
Intravenous infusion
Intravenous infusion
PrednisoloneDrug
Route of administration based on locally sourced product
SirolimusDrug
Route of administration based on locally sourced product
| Study group | Role | What they receive |
|---|---|---|
| Part 1 : ASP2957 Dose Escalation | Experimental | Participants will receive sequential dose levels of a single infusion of ASP2957 and immunosuppression prophylaxis including methylprednisolone, prednisolone and sirolimus. Receives: Genetic: ASP2957; Drug: Methylprednisolone; Drug: Prednisolone; Drug: Sirolimus |
| Part 2: ASP2957 Dose Expansion | Experimental | Participants will receive a single infusion of ASP2957 (dose selected in Part 1) and immunosuppression prophylaxis including methylprednisolone, prednisolone and sirolimus. Receives: Genetic: ASP2957; Drug: Methylprednisolone; Drug: Prednisolone; Drug: Sirolimus |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of participants with treatment emergent adverse events (TEAEs)
An adverse event (AE) is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease (new or exacerbated) temporally associated with the use of study intervention. This includes events related to the comparator, if applicable, and events related to the (study) procedures. A TEAE is defined as an AE observed after administration of ASP2957.
Measured: Up to week 52
Number of participants with adverse events of special interest (AESIs)
AESIs include myocardial-associated events, muscle abnormalities, hepatobiliary disorders, thrombocytopenia, TMA and life-threatening infections.
Measured: Up to week 52
Number of participants with laboratory value abnormalities and/or adverse events (AEs)
Number of participants with potentially clinically significant laboratory values.
Measured: Up to 52 weeks
Number of participants with electrocardiogram (ECG) abnormalities and/or AEs
Number of participants with potentially clinically significant ECGs.
Measured: Up to 52 weeks
Number of participants with echocardiogram (ECHO) abnormalities and/or AEs
Number of participants with potentially clinically significant ECHOs.
Measured: Up to 52 weeks
Number of participants with muscle magnetic resonance imaging (MRI) abnormalities and/or AEs
Number of participants with potentially clinically significant muscle MRIs.
Measured: Up to 52 weeks
Number of participants with histopathology abnormalities and/or AEs from muscle biopsy
Number of participants with potentially clinically significant histopathology from muscle biopsy.
Measured: Up to 52 weeks
Number of participants with physical examinations abnormalities and/or AEs
Number of participants with potentially clinically significant physical examinations.
Measured: Up to 52 weeks
Secondary outcomes (9)
Change from baseline in hours per day of ventilation support at week 52
The hours of ventilation support will be collected.
Measured: Baseline and up to week 52
ASP2957 vector deoxyribonucleic acid (DNA) in serum through week 52
ASP2957 vector DNA will be recorded from serum samples collected.
Measured: Up to week 52
ASP2957 vector DNA in muscle biopsy at week 52
ASP2957 vector DNA will be recorded from muscle biopsy collected.
Measured: Week 52
ASP2957 vector DNA in saliva
ASP2957 vector DNA will be recorded from saliva samples collected.
Measured: Up to week 52
ASP2957 vector DNA in urine
ASP2957 vector DNA will be recorded from urine samples collected.
Measured: Up to week 52
ASP2957 vector DNA in stool
ASP2957 vector DNA will be recorded from stool samples collected.
Measured: Up to week 52
Anti-MyoAAV3.8 total antibody (TAb)
Anti-MyoAAV3.8 TAb will be recorded from serum samples collected
Measured: Up to week 52
Anti-MyoAAV3.8 neutralizing antibody (NAb)
Anti-MyoAAV3.8 NAb will be recorded from serum samples collected.
Measured: Up to week 52
Anti-myotubularin TAb
Anti-myotubularin TAb will be recorded from serum samples collected.
Measured: Up to week 52
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jul 2025
- Study start15 Dec 2025
- Primary completion31 Oct 2027 (estimated)
- Study completion31 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for X-Linked Myotubular MyopathyStudies 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
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 9 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Astellas Gene Therapies
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Astellas Gene Therapies
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07052929
- Sponsor's protocol ID
- 2957-CL-0101
- Other IDs
- 2025-523213-29, 2025
- Status last verified
- Sep 2026
- First submitted
- 30 Jun 2025
- Last updated
- 3 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: Access to anonymized individual participant level data will not be provided for this trial. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.
Study at a glance
From the registry record, last updated by the sponsor on 3 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 1/2, Multicenter, Open-label, Dose Escalation and Expansion Clinical Study to Evaluate the Safety, Tolerability and Preliminary Efficacy of ASP2957 in Male Participants With Invasive Ventilator-dependent X-linked Myotubular Myopathy
- ClinicalTrials.gov ID
- NCT07052929
- Acronym / sponsor ID
- 2957-CL-0101
- Conditions
- X-Linked Myotubular Myopathy
- Keywords
- XLMTM, Recombinant Adeno-Associated Virus
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 9 participants (estimated)
- Lead sponsor
- Astellas Gene TherapiesIndustry (pharma, biotech, devices)
- Study start
- 15 Dec 2025 (actual)
- Primary completion
- 31 Oct 2027 (estimated)
- Study completion
- 31 Oct 2027 (estimated)
- First posted
- 8 Jul 2025 (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.
X-linked myotubular myopathy (XLMTM) is a rare and serious condition present at birth where the muscles do not work properly. There are currently no approved therapies for XLMTM.
The protein myotubularin is needed for muscle development, movement and breathing. A gene called MTM1 tells the body to make myotubularin. XLMTM is caused by changes, or mutations, in the MTM1 gene. Changes in the MTM1 gene cause low or no levels of myotubularin to be made, so the muscles do not work properly.
Gene therapy is a way of getting a healthy copy of a gene into the body. This allows the body's cells to make a normal protein that may reduce disease symptoms. Researchers have developed ASP2957 to get a healthy MTM1 gene into the body. This could help improve muscle development and function in young children with XLMTM.
In this study, ASP2957 will be given to humans for the first time.
ASP2957 has the healthy MTM1 gene inside a type of empty (killed) virus. The virus delivers the healthy MTM1 gene directly into cells in the body. It's possible that some boys may have antibodies to the virus if they have previously been infected with a similar virus. The antibodies could stop ASP2957 from working properly and cause an immune reaction to ASP2957. To prevent this, the boys will also be given medicines to lower the immune system.
The main aims of this study are to check the safety of ASP2957, how well it is tolerated, and to find a suitable dose of ASP2957.
The study was designed in 2 phases. In Phase 1, different small groups of boys will receive lower to higher doses of ASP2957. Each boy will receive a single infusion of ASP2957. Any medical problems will be recorded for each dose. This is done to find a suitable dose of ASP2957 to use in Phase 2.
In Phase 2, another small group of young boys will receive a single infusion of ASP2957. The most suitable dose of ASP2957 worked out from Phase 1 will be used.
The boys will be checked for up to 1 year after their single infusion of ASP2957. After this, there will be the option for the boys to join another study so they will continue to be checked longer term.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Part 1 : ASP2957 Dose Escalation | Experimental | Genetic: ASP2957, Drug: Methylprednisolone, Drug: Prednisolone, Drug: SirolimusParticipants will receive sequential dose levels of a single infusion of ASP2957 and immunosuppression prophylaxis including methylprednisolone, prednisolone and sirolimus. |
| Part 2: ASP2957 Dose Expansion | Experimental | Genetic: ASP2957, Drug: Methylprednisolone, Drug: Prednisolone, Drug: SirolimusParticipants will receive a single infusion of ASP2957 (dose selected in Part 1) and immunosuppression prophylaxis including methylprednisolone, prednisolone and sirolimus. |
Who may qualify
- Ages
- Up to 36 months
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (17 listed)
- Participant is projected to be ≤ 36 months of age at dosing.
- Participant has molecular genetic report from a CAP-approved testing facility at screening that confirms a diagnosis of XLMTM and harbors a "pathogenic" or "likely pathogenic" variant in the MTM1 gene as classified using the American College of Medical Genetics (ACMG) standards and guidelines for interpretation of sequence variants. Although samples will be sent to the sponsor central laboratory during screening for exploratory testing, results of this testing are not required for enrollment.
- Participant is ventilator-dependent and meets the following criteria:
- Participant has no evidence of hepatic peliosis, increased echogenicity or any other clinically important abnormal finding on liver ultrasound.
- Participant can receive immunosuppression per protocol.
Key exclusion criteria (30 listed)
- Participant born < 35 weeks gestation is still not term as per corrected age.
- Participant is nutritionally unstable with weight less than fifth percentile for age or has a vitamin A, E or K deficiency.
- Participant requires supplemental oxygen on a routine or chronic basis.
- Participant currently has a clinically important respiratory infection or other clinically important active infection of any kind.
- Participant has an active viral or bacterial infection including, but not limited to, positive testing for the following:
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 |
|---|---|---|
| ASP2957Also: MyoAAV3.8 engineered capsid - myosin heavy chain kinase 7 - human myotubularin (MyoAAV3.8-MHCK7-hMTM1)Intravenous infusion | Genetic | Part 1 : ASP2957 Dose Escalation, Part 2: ASP2957 Dose Expansion |
| MethylprednisoloneIntravenous infusion | Drug | Part 1 : ASP2957 Dose Escalation, Part 2: ASP2957 Dose Expansion |
| PrednisoloneRoute of administration based on locally sourced product | Drug | Part 1 : ASP2957 Dose Escalation, Part 2: ASP2957 Dose Expansion |
| SirolimusRoute of administration based on locally sourced product | Drug | Part 1 : ASP2957 Dose Escalation, Part 2: ASP2957 Dose Expansion |
Primary outcome
Number of participants with treatment emergent adverse events (TEAEs)
Time frame: Up to week 52
An adverse event (AE) is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease (new or exacerbated) temporally associated with the use of study intervention. This includes events related to the comparator, if applicable, and events related to the (study) procedures. A TEAE is defined as an AE observed after administration of ASP2957.
Number of participants with adverse events of special interest (AESIs)
Time frame: Up to week 52
AESIs include myocardial-associated events, muscle abnormalities, hepatobiliary disorders, thrombocytopenia, TMA and life-threatening infections.
Number of participants with laboratory value abnormalities and/or adverse events (AEs)
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant laboratory values.
Number of participants with electrocardiogram (ECG) abnormalities and/or AEs
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant ECGs.
Number of participants with echocardiogram (ECHO) abnormalities and/or AEs
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant ECHOs.
Number of participants with muscle magnetic resonance imaging (MRI) abnormalities and/or AEs
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant muscle MRIs.
Number of participants with histopathology abnormalities and/or AEs from muscle biopsy
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant histopathology from muscle biopsy.
Number of participants with physical examinations abnormalities and/or AEs
Time frame: Up to 52 weeks
Number of participants with potentially clinically significant physical examinations.
9 secondary outcomes
Change from baseline in hours per day of ventilation support at week 52
Time frame: Baseline and up to week 52
ASP2957 vector deoxyribonucleic acid (DNA) in serum through week 52
Time frame: Up to week 52
ASP2957 vector DNA in muscle biopsy at week 52
Time frame: Week 52
ASP2957 vector DNA in saliva
Time frame: Up to week 52
ASP2957 vector DNA in urine
Time frame: Up to week 52
ASP2957 vector DNA in stool
Time frame: Up to week 52
Anti-MyoAAV3.8 total antibody (TAb)
Time frame: Up to week 52
Anti-MyoAAV3.8 neutralizing antibody (NAb)
Time frame: Up to week 52
Anti-myotubularin TAb
Time frame: Up to week 52
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 3 Sep 2026.
- Individual participant dataSharing planned: No. Access to anonymized individual participant level data will not be provided for this trial. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.
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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.
Medical Director study director
Astellas Gene Therapies
5 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing ASP2957, Methylprednisolone and Prednisolone in people with X-Linked Myotubular Myopathy, run by Astellas Gene Therapies at 5 sites in 2 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 17 inclusion and 30 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 3 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 5 sites in United States, Canada. 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 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 Astellas Gene Therapies (800-888-7704, Astellas.registration@astellas.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants with treatment emergent adverse events (TEAEs) (time frame: Up to week 52). The study lists 8 primary outcomes in all. 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 3 Sep 2026.