Safety and Efficacy of KER-065 in Participants With Duchenne Muscular Dystrophy

A Multicenter, Phase 2, Open-Label Study Evaluating the Safety and Efficacy of KER-065 in Participants With Duchenne Muscular Dystrophy

The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy of KER-065 administered to adult and pediatric ambulatory and nonambulatory male participants with Duchenne Muscular Dystrophy (DMD) on stable background therapy.

Study Overview

• Status: Not yet recruiting
• Conditions: Duchenne Muscular Dystrophy
• Intervention / Treatment: Drug: KER-065

Detailed Description

This is a Phase 2, multicenter, open-label study of KER-065.

The study will consist of 3 periods:

• Screening Period (up to 6 weeks)
• Treatment Period (96 weeks)
• Safety Follow-up Period (4 weeks)

Participants will be enrolled in parallel into 1 of 3 treatment cohorts:

• Cohort A1 (Late Ambulatory)
• Cohort A2 (Late Ambulatory)
• Cohort N1 (Nonambulatory)

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Gina Weaver; Phone Number: 267.799.3345; Email: gweaver@kerostx.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

• Diagnosis of DMD, defined as the presence of phenotypic features at screening consistent with DMD AND documented mutation in the dystrophin gene consistent with the diagnosis of DMD using a clinically validated genetic test.
• Receiving a stable regimen of systemic CS (including, but not limited to, prednisone, prednisolone, deflazacort, or vamorolone) for at least 90 days before screening.
• Body weight of ≥ 25.0 kg.

Ambulatory Participants Only (Cohort A1 and A2):

• Ambulatory, defined as able to walk independently without assistive devices.
• Able to TTR in < 10 seconds.
• Has a NSAA score ≥ 15 points.
• Cohort 2 only: Documentation of a stable dose of an approved exon-skipping therapy.

Nonambulatory Participants Only (Cohort N1):

• Nonambulatory, characterized as being unable to ambulate for a minimum of 3 months before first dose with onset of nonambulatory status AND a NSAA walk score of 0 and inability to perform the 10MWR.
• PUL v2.0 entry item score of 3 to 5, inclusive.

Key Exclusion Criteria:

• Clinical symptoms or signs of cardiomyopathy or heart failure.
• Exposure to any approved or investigational dystrophin restoration gene therapy product.
• Exposure to any approved or investigational dystrophin restoration product other than gene therapy (Except for exon-skipping therapy for Cohort A2).
• Exposure to any approved or investigational histone deacetylase inhibitor, antimyostatin therapy, therapy targeting transforming growth factor-beta ligands, or cell-based therapy.
• Use of any other pharmacological treatment, except for CS
• Treatment with immunosuppressant therapy (other than CS)
• History of fracture of the upper limb

Nonambulatory Participants Only (Cohort N1):

• Elbow-flexion contractures > 30° in both upper extremities.
• Forced vital capacity (FVC) of < 50% or requirement for daytime or nocturnal ventilation, except for nocturnal non-invasive ventilation AND inability to perform consistent FVC measurements within ± 15% during paired testing.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort A1 (Late Ambulatory); Participants will receive stable corticosteroid (CS) along with KER-065.	Drug: KER-065; KER-065 will be administered subcutaneously (SC)
Experimental: Cohort A2 (Late Ambulatory); Participants will receive stable CS, exon skipper along with KER-065.	Drug: KER-065; KER-065 will be administered subcutaneously (SC)
Experimental: Cohort N1 (Nonambulatory); Participants will receive stable CS along with KER-065.	Drug: KER-065; KER-065 will be administered subcutaneously (SC)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with treatment-emergent adverse events (TEAEs and serious adverse events (SAEs)	To evaluate the safety and tolerability of KER-065 in ambulatory and nonambulatory participants with DMD	Up to approximately 3 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
KER-065 serum concentration by visit, as appropriate	To assess the pharmacokinetics (PK) of KER-065 in ambulatory and nonambulatory participants with DMD	Up to Week 100
Number and proportion of participants with treatment-emergent ADA (antidrug antibody) by visit	To assess the immunogenicity of KER-065 in ambulatory and nonambulatory participants with DMD	Up to Week 100
Change from baseline by visit in bone mineral density (BMD), fat mass, and lean body mass, as measured by dual- energy X-ray absorptiometry (DXA)	To assess the effect of KER-065 on body composition in ambulatory and nonambulatory participants with DMD	Up to Week 96
Change from baseline by visit in muscle volume and intramuscular fat by skeletal muscle MRI	To assess the effect of KER-065 on skeletal muscle in ambulatory and nonambulatory participants with DMD	Up to Week 96
Ambulatory: Change from baseline by visit in North Star Ambulatory Assessment (NSAA) total score	To assess the effect of KER-065 on motor function in ambulatory participants with DMD	Up to Week 96
Ambulatory: Change from baseline by visit in 4-stair climb (4SC)	To assess the effect of KER-065 on motor function in ambulatory participants with DMD	Up to Week 96
Ambulatory: Change from baseline by visit in 10-meter walk/run (10MWR) test	To assess the effect of KER-065 on motor function in ambulatory participants with DMD	Up to Week 96
Ambulatory: Change from baseline by visit in TTR (time to rise)	To assess the effect of KER-065 on motor function in ambulatory participants with DMD	Up to Week 96
Nonambulatory: Change from baseline by visit in PUL (Performance of Upper Limb) v2.0 score	To assess the effect of KER-065 on motor function in nonambulatory participants with DMD	Up to Week 96

Collaborators and Investigators

• Sponsor: Keros Therapeutics, Inc.

Study record dates

Study Major Dates

• Study Start (Estimated): September 14, 2026
• Primary Completion (Estimated): July 17, 2029
• Study Completion (Estimated): August 14, 2029

Study Registration Dates

• First Submitted: July 9, 2026
• First Submitted That Met QC Criteria: July 9, 2026
• First Posted (Actual): July 15, 2026

Study Record Updates

• Last Update Posted (Actual): July 15, 2026
• Last Update Submitted That Met QC Criteria: July 9, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Pharmacokinetics; Pharmacodynamics; Recombinant fusion protein; Muscle-wasting disease; Ambulatory function
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Neuromuscular Diseases; Genetic Diseases, Inborn; Genetic Diseases, X-Linked; Muscular Disorders, Atrophic; Muscular Dystrophies; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Muscular Dystrophy, Duchenne
• Other Study ID Numbers: KER-065-B201

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes