A Phase 3 interventional study of PF-06823859 and Placebo in Myositis, sponsored by Pfizer. Recruiting at 138 sites in 20 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by Pfizer · Phase 3, Interventional, and Treatment
The purpose of the study is to understand how the study medicine PF-06823859 (dazukibart) works in people with idiopathic inflammatory myopathies (DM and PM). These disorders cause inflammation that weakens the muscles that are important for movement and may also cause skin rash in people with DM.
This study is seeking participants who:
Are receiving a stable dose of 1 corticosteroid taken by mouth and/or 1 traditional immunosuppressant.
Dermatomyositis (DM) is a rare disease that causes muscle inflammation that results in muscle weakness and low muscle stamina. Patients with DM have a characteristic skin rash. Polymyositis (PM) is a rare disease that involves mainly muscle inflammation resulting in muscle weakness, that can sometimes be painful. Patients with DM and PM may have trouble going up the steps, walking or getting to a standing position.
Some of the participants will receive the study medicine (dazukibart) and some will receive placebo (which is similar to study medicine but contains no medicine in it).
The study medicine or placebo will be given as an intravenous (IV) infusion (directly into the veins), which takes about 1 hour; every 4 weeks from Day 1 to Week 48 of the study. Both dazukibart and placebo and will be given at the study site.
The study will compare the experiences of people receiving study medication to those of the people who do not. This will help to see if dazukibart is safe and effective.
Participants will take part in this study for about 13 months. During this time, participants will have 15 study visits. These visits will be performed at the study site.
184 studies on the registry are indexed under Dermatomyositis; 63 are open to participants now.
This study's planned enrollment of 318 is above the median of 35 across 130 interventional studies indexed under Dermatomyositis.
Browse Dermatomyositis studies →Pfizer is the lead sponsor of 3,334 studies on the registry; 149 are open to participants now.
Of its 601 completed or terminated interventional studies of FDA-regulated products, 391 (65%) have results posted.
Compared within Dermatomyositis, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Myositis. The counts are of registry records indexed under each term, refreshed daily. How we classify →
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Active dermatomyositis (DM) or polymyositis (PM) with age of onset
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive placebo via intravenous infusion every 4 weeks.
Drug: Placebo
Participants will receive PF-06823859 via intravenous infusion every 4 weeks.
Drug: PF-06823859
anti-interferon beta therapy
Placebo for PF-06823859
Moderate change in Total Improvement Score (TIS)
Total Improvement Score 0 to 100 with higher scores indicating a better outcome.
Time frame: 24 weeks outside of the United States (US) and 52 weeks in the US
Change from baseline in Manual Muscle Testing - 8 designated muscles (MMT-8)
Manual Muscle Testing (8 designated muscles) 0 to 150 with higher scores indicating a better outcome
Time frame: 24 weeks outside of the US and 52 weeks in the US
Change from baseline in Cutaneous Dermatomyositis Disease Area and Severity Index Activity Score (CDASI-A) in participants with dermatomyositis (DM)
Cutaneous Dermatomyositis Disease Area and Severity Index Activity Score 0 to 100 with higher scores indicating a worse outcome. Only participants with baseline CDASI-A score ≥14 will be assessed.
Time frame: Week 24 outside the US
Change from baseline in Investigator Global Assessment severity scale (IGA) in participants with dermatomyositis
Investigator Global Assessment severity scale 0 to 4 with higher scores indicating a worse outcome. Only participants with baseline IGA ≥2 will be assessed
Time frame: 24 and 52 weeks in the US only
Corticosteroid (CS) dose assessment
Normalized Area Under the Curve (AUC) of corticosteroid dose
Time frame: 52 weeks
Moderate change in Total Improvement Score
Total Improvement Score 0 to 100 with higher scores indicating a better outcome.
Time frame: 24 weeks in the US and 52 weeks outside of the US
Change from baseline in Patient-Reported Outcomes Measurement Information System - Physical Function (PROMIS-PF)
Patient-Reported Outcomes Measurement Information System - Physical Function 0 to 100 with higher scores indicating a better outcome
Time frame: 24 weeks outside of the US and 52 weeks in the US
Change from baseline in 5-D Itch Scale Score
5-D Pruritis Scale 5 to 25 with higher scores indicating a worse outcome. Only participants with baseline CDASI-A score ≥14 will be assessed.
Time frame: 24 weeks outside of the US and 52 weeks in the US
Change from baseline in Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F)
Functional Assessment of Chronic Illness Therapy - Fatigue 0 to 52 with higher scores indicating a better outcome
Time frame: 24 weeks outside of the US and 52 weeks in the US
Response in corticosteroid tapering
At least 50% reduction from baseline or reduction in corticosteroid (CS) dose to \<7.5 mg/day at Week 52 for participants with baseline CS dose ≥10 mg/day.
Time frame: 52 weeks US only
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Showing the first 100 of 138 sites across 20 countries. Choose a country and city above to see the rest.
Plan to share: Yes — Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
Data sharing details ↗ · www.pfizer.com
Started May 2023 (actual). Primary completion is estimated for Jul 2030, 86 months after the start.
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Studies of the drug tested here: Dazukibart