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)

NCT ID: NCT05669014

Last Updated: 2025-11-03

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE2

Total Enrollment

12 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-12-04

Study Completion Date

2025-07-02

Brief Summary

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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

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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

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Idiopathic Inflammatory Myositis

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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Daxdilimab

Daxdilimab will be administered by subcutaneous (SC) injection during the 24-week treatment period followed by an 8-week safety follow up.

Prior to amendment 2 participants could enter an open-label extension period from weeks 24-48. For those participants already in the open-label extension, they will stop dosing and enter the safety follow up.

Group Type EXPERIMENTAL

Daxdilimab

Intervention Type DRUG

Participants will be administered daxdilimab by subcutaneous (SC) injection.

Placebo

Matching placebo will be administered by SC injection during the 24-week treatment period followed by an 8-week safety follow up.

Prior to amendment 2 participants could enter an open-label extension period from weeks 24-48 and receive daxdilimab. For those participants already in the open-label extension, they will stop dosing and enter the safety follow up.

Group Type PLACEBO_COMPARATOR

Daxdilimab

Intervention Type DRUG

Participants will be administered daxdilimab by subcutaneous (SC) injection.

Placebo

Intervention Type DRUG

Participants will be administered identically matching placebo by SC injection.

Interventions

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Daxdilimab

Participants will be administered daxdilimab by subcutaneous (SC) injection.

Intervention Type DRUG

Placebo

Participants will be administered identically matching placebo by SC injection.

Intervention Type DRUG

Other Intervention Names

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HZN-7734

Eligibility Criteria

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Inclusion Criteria

1. Adult men or women 18 and ≤ 75 years of age at the time of signing the informed consent (ICF).
2. A diagnosis of definite or probable myositis according to American College of Rheumatology/European League Against Rheumatism 2017 (ACR/EULAR 2017) criteria:

1. Population 1: DM

* Diagnosis of DM with DM rash current or historical, or
2. Population 2: ASIM

* Anti-histidyl tRNA synthetase-(Anti-Jo-1) antibodies must be positive during screening by central laboratory testing, or
* One of following antibodies must be positive by historical testing: directed against anti-alanyl- (anti-PL-12), anti-threonyl-(anti PL-7), anti-asparaginyl-(anti-KS), anti-glycyl-(anti-EJ), anti-isoleucyl-(anti-OJ), anti-phenylalanyl-transfer RNA synthetase-(anti-ZO), anti-tyrosil-YRS(HA).
3. Currently active myositis with all the following (a, b, and c) during screening:

1. Manual Muscle Testing (MMT 8) score \< 142
2. At least 2 other abnormal core set measures (CSM) from the following list:

* Patient global disease activity (PtGDA) ≥ 2 cm in a 10 cm visual analog scale (VAS)
* Physician's Global Disease Activity (PhGDA) ≥ 2 cm in a 10 cm VAS
* Extramuscular activity ≥ 2cm in a 10 cm VAS
* At least one muscle enzyme 1.5 times upper limit of normal (ULN)
* Health assessment questionnaire-disability index (HAQ-DI) ≥ 0.5
3. Global muscle damage score ≤ 5 on a 10 cm VAS on the myositis damage index (MDI).
4. Participants should be on stable standard of care therapy if tolerated; if they are not able to tolerate it or have failed standard of care, medications should have a washed out period.
5. Participants should be willing to taper corticosteroid dose per protocol when stable or improving.

Exclusion Criteria

1. Any condition that, in the opinion of the investigator or sponsor, would interfere with the evaluation of investigational product (IP) or interpretation of participant safety or study results.
2. Weight \> 160 kg (352 pounds) at screening.
3. Breastfeeding or pregnant women or women who intend to become pregnant anytime from signing the ICF through 6 months after receiving the last dose of IP.
4. History of clinically meaningful cardiac disease including unstable angina, myocardial infarction, congestive heart failure within 6 months prior to randomization; arrhythmia requiring active therapy, except for clinically insignificant extra systoles, or minor conduction abnormalities; or presence of clinically meaningful abnormality on electrocardiogram (ECG) if, in the opinion of the Investigator, it would increase the risk of study participation.
5. History of cancer within the past 5 years except cutaneous basal cell or squamous cell carcinoma treated with curative therapy.
6. Any underlying condition that in the opinion of the Investigator significantly predisposes the participant to infection (eg. hepatitis C).
7. Known history of a primary immunodeficiency or an underlying condition, such as known human immunodeficiency virus (HIV) infection, or a positive result for HIV infection per central laboratory.
8. All participants will undergo testing for hepatitis B virus serology as defined in the protocol.
9. Active tuberculosis (TB), or a positive interferon gamma (IFN-γ) release assay (IGRA) test at screening, unless documented history of appropriate treatment for active or latent TB according to local guidelines.
10. Any severe herpes virus family infection (including Epstein-Barr virus, cytomegalovirus \[CMV\]) at any time prior to randomization.
11. Opportunistic infection requiring hospitalization or parenteral antimicrobial treatment within 2 years prior to randomization.
12. Significant organ system involvement or myositis damage (global muscle damage score \> 5 on a 10 cm VAS scale on the MDI) that poses risks in the study or impedes assessments.
13. Diagnosis of immune-mediated necrotizing myopathy (IMNM) \[(positive 3-hydroxy-3-methylglutaryl-coenzyme A reductase (anti-HMGR), anti-signal recognition particle (anti- SRP), or antibody negative)\], inclusion body myositis (IBM) (including positive anti-cytosolic 5'-nucleotidase 1A (anti cN1A), or drug-induced myositis.
14. Current musculoskeletal, joint, or inflammatory disease, including significant joint contractures or calcinosis that in the opinion of the investigator, could interfere with the muscle strength assessments and confound the disease activity assessments.
15. Wheelchair bound participants.
16. Current inflammatory skin disease other than DM or ASIM that, in the opinion of the investigator, could interfere with the inflammatory skin assessments or confound the disease activity assessments.
17. Severe interstitial lung disease where respiratory symptoms limit participant function or progressive pulmonary fibrosis.
18. Myositis in overlap with another connective tissue disease that precludes the accurate assessment of a treatment response (for example, difficulty in assessing muscle strength in a scleroderma patient with associated myositis).
Minimum Eligible Age

18 Years

Maximum Eligible Age

75 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Amgen

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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MD

Role: STUDY_DIRECTOR

Amgen

Locations

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Advanced Research Center, Inc.

Anaheim, California, United States

Site Status

Centro Mineiro de Pesquisa - CMiP

Juiz de Fora, Minas Gerais, Brazil

Site Status

LMK Servicos Medicos SS

Porto Alegre, Rio Grande do Sul, Brazil

Site Status

Revmatologicky ustav

Prague, Praha, Hlavní Mesto, Czechia

Site Status

Unidad de Investigacion de las Enfermedades Reumaticas S.A. De C.V.

Mexico City, , Mexico

Site Status

Accelerium, S. de R.L. de C.V. - PPDS

Monterrey, , Mexico

Site Status

Hospital Quironsalud Infanta Luisa

Seville, , Spain

Site Status

Aintree University Hospital - NWCRN - PPDS

Liverpool, Merseyside, United Kingdom

Site Status

Western General Hospital Edinburgh - PPDS

Edinburgh, Midlothian, United Kingdom

Site Status

Countries

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United States Brazil Czechia Mexico Spain United Kingdom

Related Links

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http://www.amgentrials.com

AmgenTrials clinical trials website

Other Identifiers

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2022-502810-10-00

Identifier Type: OTHER

Identifier Source: secondary_id

HZNP-DAX-205

Identifier Type: -

Identifier Source: org_study_id

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