A Phase 2 interventional study of BMN 351 in Duchenne Muscular Dystrophy (DMD), sponsored by BioMarin Pharmaceutical. Enrolling by invitation at 6 sites in 5 countries. Open to male participants aged 4 Years and older. Per ClinicalTrials.gov, last updated 2026-07-24.
Sponsored by BioMarin Pharmaceutical · Phase 2, Interventional, and Treatment
This open-label extension study aims to evaluate the long-term safety and tolerability of weekly BMN 351 infusions, as well as to assess the effect of BMN 351 on physical function, in participants with DMD who participated in the 351-201 study.
This Phase 2, multi-center, open-label extension study is designed to assess the long-term safety, tolerability, and functional efficacy of weekly intravenous doses of BMN 351 administered to participants with Duchenne muscular dystrophy (DMD) amenable to exon 51 skipping in the Phase 1/2 study, 351-201. Up to 18 participants ages 4 through 23 at baseline will enroll in the trial after completing 351-201.
The first visit for this study is the same as the final visit of 351-201. To be eligible for this study, potential participants must satisfy the eligibility criteria described in the protocol.
481 studies on the registry are indexed under Muscular Dystrophy, Duchenne; 108 are open to participants now.
This study's planned enrollment of 18 is below the median of 26 across 332 interventional studies indexed under Muscular Dystrophy, Duchenne.
Browse Muscular Dystrophy, Duchenne studies →BioMarin Pharmaceutical is the lead sponsor of 112 studies on the registry; 13 are open to participants now.
Of its 17 completed or terminated interventional studies of FDA-regulated products, 12 (71%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Currently receiving treatment with oral , on a stable dose regimen during 351-201, and must remain on a consistent dose regimen throughout 351-202 or 351-203 except for modifications to accommodate changes in weight
Willing to use (sexually mature males) throughout the study and for 90 days after the final dose, if sexually active
Exclusion Criteria:
Are taking any prohibited medications
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants from 351-201 enrolling in 351-202 will initially receive BMN 351 at the dose level at which they completed 351-201. Once all 351-201 participants have completed their Week 25 visit in 351-202, available safety and PD data will be analyzed and a single optimal dose level will be selected for 351-202. All participants from 351-201 will transition to that dose level at their next applicable visit.
Drug: BMN 351
Anti-sense Oligonucleotide BMN 351 will be administered intravenously
To assess the long-term safety and tolerability of BMN 351 in participants with DMD
The safety and tolerability of BMN 351 will be assessed based on the incidence of adverse and serious adverse events.
Time frame: Through study completion, at least 1 year
To evaluate the effect of BMN 351 on physical function
North Star Ambulatory Assessment (NSAA) will be assessed at the specific visits and compared to individual baseline and external controls
Time frame: Change from baseline and subsequent 24-week incremental visits
To evaluate the effect of BMN 351 on physical function
Timed 4 stair climb (4SC) will be assessed at the specified visits and compared to individual baseline and external controls
Time frame: Change from baseline and subsequent 24-week incremental visits
To evaluate the effect of BMN 351 on physical function
SV95C will be assessed at the specified visits and compared to individual baseline and external controls
Time frame: Change from baseline and subsequent 24-week incremental visits
To evaluate the effect of BMN 351 on physical function
PUL 2.0 will be assessed at the specified visits and compared to individual baseline and external controls
Time frame: Change from baseline and subsequent 24-week incremental visits
Started Apr 2026 (actual). Primary completion is estimated for Dec 2031, 68 months after the start.
Of 40 industry-sponsored phase 2 interventional studies under Muscular Dystrophy, Duchenne, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 20 and three quarters within 42. This study's planned 68 months is above that.
Counting every sponsor, half of 47 studies reached it within 31 months; a quarter within 20 and three quarters within 42.
How these figures are worked out, and which studies are left out of them.
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Muscular Dystrophy, Duchenne →