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Evaluating Anifrolumab for Treating Polymyositis and Dermatomyositis

A Multicenter, Parallel-group, Double-blind, 2-Arm, Phase III Study to Investigate the Efficacy and Safety of Anifrolumab Administered as Subcutaneous Injection and Added to Standard of Care Compared With Placebo Added to Standard of Care in Adult Participants With Idiopathic Inflammatory Myopathies (Polymyositis and Dermatomyositis)

Phase 3 Interventional AstraZeneca · NCT06455449

This study is testing if a new drug called anifrolumab can help adults with polymyositis and dermatomyositis feel better compared to a placebo while they continue their usual treatments.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment240 (estimated)
Ages18 Years to 75 Years
SexAll
SponsorAstraZeneca Industry-sponsored
Drugs / interventionsprednisone, anifrolumab
Locations234 sites (Phoenix, Arizona and 233 other locations)
Trial IDNCT06455449 on ClinicalTrials.gov

What this trial studies

This multicenter, randomized, placebo-controlled, double-blind study aims to assess the efficacy and safety of subcutaneous anifrolumab in adults with moderate to severe idiopathic inflammatory myopathies, specifically polymyositis and dermatomyositis. Participants will receive either anifrolumab or a placebo alongside standard of care treatments. The study will measure overall disease activity using established core set measurements to determine the impact of anifrolumab compared to placebo.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 to 75 with a confirmed diagnosis of polymyositis or dermatomyositis and moderate to severe disease activity.

Not a fit: Patients with other forms of myositis or those at high risk of malignancy may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve disease management for patients with polymyositis and dermatomyositis.

How similar studies have performed: Previous studies have shown promise with similar biologic treatments in inflammatory myopathies, suggesting potential for success with this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Capable of giving informed consent.

Inclusion Criteria:

1. 18 - 75 years old
2. Body weight ≥40 kg
3. Must have "probable" or "definite" diagnosis of PM or DM according to the 2017 ACR/EULAR classification criteria for adult myositis.
4. Moderate or severe disease activity per core set measurements.
5. Currently receiving oral prednisone or other polymyositis or dermatomyositis treatments at a stable dose.
6. No history of active tuberculosis or severe COVID-19.
7. Male and female participants must follow contraception guidelines.

Exclusion Criteria:

1. Participants with documented inclusion body myositis (IBM), immune mediation necrotizing myositis (IMNM), juvenile myositis (if diagnosed within 10 years prior to signing the ICF), drug-induced myositis, cancer associated myositis, amyopathic DM, and non inflammatory myopathies (eg, muscular dystrophies).
2. PM and DM patients at a high risk of malignancy.
3. Participants with rapidly progressive interstitial lung disease.
4. Participants with severe muscle damage or permanent weakness due to non-PM or non-DM conditions (i.e. stroke) as per the investigator's opinion.
5. Any history of severe case of herpes zoster infection
6. History of cancer (except adequately treated basal cell carcinoma or cervical cancer in-situ), immunodeficiency, HIV, HBV, active HCV .
7. Any clinical cytomegalovirus or Epstein-Barr virus infection that has not completely resolved within 12 weeks prior to signing the ICF.
8. Opportunistic infection requiring hospitalization or IV antimicrobial treatment within 3 years prior to randomization.
9. Recent non-opportunistic infection requiring hospitalization or anti-infective treatment.
10. Recent or concurrent enrollment in another clinical study with an investigational product.
11. Lactating, breastfeeding, or pregnant females or females who intend to become pregnant or begin breastfeeding

Where this trial is running

Phoenix, Arizona and 233 other locations

+184 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Polymyositis, DermatomyositisPolymyositisDermatomyositisanifrolumab
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.