An Open-Label Extension Study to Evaluate the Long-term Safety and Efficacy of BMN 351 in Participants with Duchenne Muscular Dystrophy

Status Authorised, recruitment pending · 3 EU/EEA countries · 4 sites · Protocol 351-202

Overview

Sponsor-declared trial summary

Phase Therapeutic exploratory (Phase II)

Status Authorised, recruitment pending

Participants planned 13

Countries 3

Sites 4

Duchenne Muscular Dystrophy

To assess the long-term safety and tolerability of BMN 351 in participants with DMD

Key facts

Sponsor: Biomarin Pharmaceutical Inc.
Participant type: Pediatric, Patients
Age range: 0-17 years, 18-64 years
Gender: Male
Therapeutic area: Diseases [C] - Musculoskeletal Diseases [C05]
Decision date (initial): 2026-03-16
Transition trial: No
Low-intervention: No
Rare-disease indication: Yes
Vulnerable population: Yes
Funding sources: BioMarin Pharmaceutical Inc.

External identifiers

EU CT number: 2024-511656-41-00
WHO UTN: U1111-1303-9845

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Others, Pharmacokinetic, Pharmacodynamic, Safety, Efficacy

To assess the long-term safety and tolerability of BMN 351 in participants with DMD

Secondary objectives 1

To evaluate the effect of BMN 351 on physical function

Conditions and MedDRA coding

Duchenne Muscular Dystrophy

Version	Level	Code	Term	System organ class
20.0	PT	10013801	Duchenne muscular dystrophy	100000004850

Regulatory references

Scientific advice from competent authorities: Medicines Evaluation Board, Federal Institute For Drugs And Medical Devices
Plan to share IPD: No

EU CT number	Title	Sponsor
2023-506737-30-00	A Phase 1/2, Open-Label, Dose Escalation Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Multiple Intravenous Doses of BMN 351 in Participants with Duchenne Muscular Dystrophy	Biomarin Pharmaceutical Inc.

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

Participants must have completed 351-201 or 351-203 studies without permanent discontinuation of the investigational medicinal product (IMP) or withdrawal from the study
Currently receiving treatment with oral corticosteroids, 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 contraception (sexually mature males) throughout the study and for 90 days after the final dose, if sexually active

Exclusion criteria 1

Have known coagulation disorder

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

Incidence of adverse events/SAEs/AESI, physical examination, safety laboratory test parameters, ECG parameters, echocardiogram

Secondary endpoints 4

NSAA (total score and selected individual components, i.e., timed 10MWRT and TTR) at baseline and subsequent Q24W visits
Timed 4SC at baseline and subsequent Q24W visits
SV95C (4-week monitoring periods preceding baseline and subsequent Q24W visits)
PUL 2.0 at baseline and subsequent Q24W visits

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Exon 51 specific phosphorothioate oligonucleotide

PRD10564554 · Product

Active substance: BMN 351
Pharmaceutical form: CONCENTRATE FOR SOLUTION FOR INFUSION
Route of administration: INTRAVENOUS INFUSION
Max daily dose: 12 mg/kg milligram(s)/kilogram
Max total dose: 3564 mg/Kg milligram(s)/kilogram
Max treatment duration: 297 Week(s)
Authorisation status: Not Authorised
ATC code: NOTASSIGN — -
MA holder: BIOMARIN PHARMACEUTICAL INC.
Paediatric formulation: No
Orphan designation: No

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Biomarin Pharmaceutical Inc.

Sponsor organisation: Biomarin Pharmaceutical Inc.
Address: 105 Digital Drive
City: Novato
Postcode: 94949-8703
Country: United States

Scientific contact point

Organisation: Biomarin Pharmaceutical Inc.
Contact name: Clinical Trial Information Desk

Public contact point

Organisation: Biomarin Pharmaceutical Inc.
Contact name: Clinical Trial Information Desk

Third parties 15

Organisation	City, country	Duties
Transperfect Translations International Inc. ORG-100043494	New York, United States	Other
Medidata Solutions Inc. ORG-100016256	New York, United States	E-data capture
Evidera Limited ORG-100028239	London, United Kingdom	Other
Clario Medical Imaging Inc. ORG-100052770	Seattle, United States	Other
Suvoda LLC ORG-100043523	Conshohocken, United States	Interactive response technologies (IRT)
ATOM International Limited ORG-100042393	Gateshead, United Kingdom	Other
Sysnav ORG-100026890	Vernon, France	Other
Agada Biosciences Inc. ORG-100051126	Halifax, Canada	Laboratory analysis
Azenta US Inc. ORG-100012907	Plainfield, United States	Other
Medpace Finland Oy ORG-100009147	Helsinki, Finland	On site monitoring, Code 2, Data management
Mde Healthcare Services Limited ORG-100052452	Bracknell, United Kingdom	Other
Emvenio Clinical Research LLC ORG-100044408	Denver, United States	Other
Labcorp Central Laboratory Services SARL ORG-100011524	Meyrin, Switzerland	Laboratory analysis
Bioagilytix Labs LLC ORG-100013030	Durham, United States	Laboratory analysis
Ardena Bioanalysis B.V. ORG-100036987	Assen, Netherlands	Laboratory analysis

Locations

3 EU/EEA countries · 4 investigational sites

By country

Country	MS status	Planned subjects	Sites
Italy	Authorised, recruitment pending	2	2
Netherlands	Authorised, recruitment pending	1	1
Spain	Authorised, recruitment pending	2	1
Rest of world United Kingdom, Turkey	—	8	—

Investigational sites

Italy

2 sites · Authorised, recruitment pending

Centro Clinico Nemo

Centro Clinico NeMo, Piazza Dell'ospedale Maggiore 3, 20162, Milan

Fondazione Policlinico Universitario Agostino Gemelli IRCCS

UOSD Centro Clinico Nemo Pediatrico, Largo Francesco Vito 1, 00168, Rome

Netherlands

1 site · Authorised, recruitment pending

Leids Universitair Medisch Centrum (LUMC)

Neurology, Albinusdreef 2, 2333 ZA, Leiden

Spain