Clinical trial 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)
Official title: 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.
Study type: INTERVENTIONAL
Overall status: ACTIVE_NOT_RECRUITING
Phase: PHASE2
Conditions: Idiopathic Inflammatory Myositis
Keywords: Anti-synthetase syndrome
Myositis
Polymyositis
Lead sponsor: Amgen
Sponsor class: INDUSTRY
First posted: 2022-12-30
Enrollment: 12
Sex: ALL
Minimum age (years): 18
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief 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.

Eligibility criteria: Key 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).

Primary outcomes:
measure: Efficacy of daxdilimab compared to placebo as measured by Total Improvement Score (TIS)
timeFrame: At Week 24
Secondary outcomes:
measure: Proportion of participants with improvement of TIS ≥ 40 and without deterioration at 2 consecutive visits at 24 weeks
timeFrame: At 24 Weeks
measure: Proportion of participants with improvement of TIS ≥ 20 and without deterioration at 2 consecutive visits at 24 weeks
timeFrame: At 24 Weeks
measure: Change in the cutaneous dermatomyositis disease area and severity index (CDASI) activity score from Baseline (Day 1) to Week 24
timeFrame: Baseline (Day1) to Week 24
measure: Proportion of participants on an oral corticosteroid (OCS) dose ≥ 10 mg of prednisone or equivalent at baseline who achieve a clinically meaningful reduction in the OCS dose at Week 24
timeFrame: Baseline to Week 24
measure: Serum concentration of daxdilimab over time
timeFrame: Baseline to Week 56
measure: Proportion of the participants with anti-drug antibodies (ADA) positive post-baseline only or boosted their pre-existing ADA during the study period.
timeFrame: Baseline to Week 56
measure: Incidence of ADA directed against daxdilimab over time
timeFrame: Baseline to Week 56
measure: Titer of ADA to daxdilimab over time
timeFrame: Baseline to Week 56
measure: Incidence of treatment emergent adverse events (TEAEs)
timeFrame: Baseline to Week 56
measure: Incidence of treatment emergent serious adverse events (TESAEs)
timeFrame: Baseline to Week 56
measure: Incidence of treatment emergent adverse events of special interest (TEAESIs)
timeFrame: Baseline to Week 56
Other outcomes:
Locations:
city: Anaheim
country: United States
facility: Advanced Research Center, Inc.
state: California
city: Juiz De Fora
country: Brazil
facility: Centro Mineiro de Pesquisa - CMiP
state: Minas Gerais
city: Porto Alegre
country: Brazil
facility: LMK Servicos Medicos SS
state: Rio Grande Do Sul
city: Prague
country: Czechia
facility: Revmatologicky ustav
state: Praha, Hlavní Mesto
city: Mexico city
country: Mexico
facility: Unidad de Investigacion de las Enfermedades Reumaticas S.A. De C.V.
city: Monterrey
country: Mexico
facility: Accelerium, S. de R.L. de C.V. - PPDS
city: Sevilla
country: Spain
facility: Hospital Quironsalud Infanta Luisa
city: Liverpool
country: United Kingdom
facility: Aintree University Hospital - NWCRN - PPDS
state: Merseyside
city: Edinburgh
country: United Kingdom
facility: Western General Hospital Edinburgh - PPDS
state: Midlothian
Study officials:
affiliation: Amgen
name: MD
role: STUDY_DIRECTOR
References: