NCT05669014

A Phase 2 Proof of Concept Study to Evaluate the Efficacy and Safety of Daxdilimab in Participants With Dermatomyositis (DM) or Anti-synthetase Inflammatory Myositis (ASIM)

A Phase 2, Randomized, Double-blind, Placebo-controlled, Efficacy and Safety Study of Daxdilimab Subcutaneous Injection in Adult Participants With Inadequately Controlled Dermatomyositis or Anti-synthetase Inflammatory Myositis.

• Status: Completed
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 12 (actual)
• Sponsor: Amgen · Industry
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

The primary efficacy objective: To evaluate the effect of daxdilimab compared with placebo in reducing disease activity at Week 24. The secondary efficacy objectives include: 1. To evaluate the effect of daxdilimab compared with placebo in reducing disease activity at Week 24. 2. To evaluate the effect of daxdilimab compared with placebo on skin symptoms at Week 24. 3. To evaluate the effect of daxdilimab on decreasing the use of corticosteroid at Week 24. Other secondary objectives include: 1. To characterize the pharmacokinetics (PK) and immunogenicity of daxdilimab in participants. 2. To evaluate the safety and tolerability of daxdilimab in participants.

Detailed description

The study will enroll participants with 2 idiopathic inflammatory myositis populations: * Population 1 or dermatomyositis (DM): participants with DM with definite or probable myositis according to the American College of Rheumatology/European League Against Rheumatism 2017 (ACR/EULAR 2017) criteria and a DM rash. * Population 2 or anti-synthetase inflammatory myositis (ASIM): participants with ASIM with definite or probable myositis according to ACR/EULAR 2017 criteria and a positive ASIM associated antibody. Participants will be randomized by population in a 1:1 ratio and receive investigational product (IP) daxdilimab or placebo by subcutaneous injection. The estimated total study duration will be up to 36 weeks (up to 60 weeks for those participants who entered the open-label extension prior to amendment 2.) Acquired from Horizon in 2024.

Conditions

• Idiopathic Inflammatory Myositis

Interventions

Type	Name	Description
DRUG	Daxdilimab	Participants will be administered daxdilimab by subcutaneous (SC) injection.
DRUG	Placebo	Participants will be administered identically matching placebo by SC injection.

Timeline

• Start date: 2023-12-04
• Primary completion: 2025-07-02
• Completion: 2025-07-02
• First posted: 2022-12-30
• Last updated: 2025-11-03

Locations

9 sites across 6 countries: United States, Brazil, Czechia, Mexico, Spain, United Kingdom

Regulatory

• FDA-regulated drug study