The goal of this clinical trial is to learn if the drug Maraviroc works to treat refractory idiopathic inflammatory myopathy (myositis) in patients who have not responded well to traditional therapies. It will also learn about how the drug affects muscle inflammation and function. The main questions it aims to answer are: Does Maraviroc reduce inflammation in the muscles? Does Maraviroc improve patients' muscle function and overall clinical symptoms? This is an open-label study, meaning researchers will give Maraviroc to all participants (there is no placebo) to see if the drug works to treat refractory myositis. Participants will: Take a 300mg Maraviroc tablet every day for 12 weeks. Undergo exams and tests with their doctors to check their muscle function, symptom improvement, and specific health markers (like enzyme levels).

Objective:

This is an open-label clinical trial using Maraviroc for the treatment of refractory idiopathic inflammatory myopathy (myositis).

The hypothesis to be tested:

Findings from our pilot study demonstrate that Maraviroc has an anti-inflammatory effect in both dystrophic and aging muscle. We thus hypothesize that Maraviroc can be used for treating patients with refractory myositis by repressing the inflammation in muscles.

Design and subjects:

10 patients with refractory myositis who do not respond well to traditional therapy will be recruited for the clinical trial. The patients will receive Maraviroc tablets 300mg daily for 12 weeks of treatment, and their myositis-related manifestations will be examined to evaluate the treatment effect.

Main outcome measures:

The primary outcome for the trial will be the IMACS definition of minimal clinical improvement (DOI). IMACS defined the 2016 ACR/EULAR criteria for clinical response based on 6 core set measurements (CSMs), including physician global activity, patient global activity, MMT-8, health assessment questionnaire, enzymes, and extramuscular activity score. The total improvement score is the sum of all 6 improvement scores of each core set measure.

Expected results:

The Maraviroc treatment is expected to reduce inflammation in muscles and improve muscle function in patients.

Inclusion Criteria:

1. ≥18 to <80 years of age
2. Myositis disease onset >18 years
3. Fulfillment of 2017 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) IIM classification criteria
4. Active myositis defined as Manual Muscle Testing 8 (MMT8) score <142 with at least two other abnormal International Myositis Assessment & Clinical Studies Group (IMACS) core set measures (Visual Analogue Scale (VAS) of patient global activity ≥2 cm, physician's global disease activity ≥2 cm, at least one muscle enzyme >1.5 times upper limit of normal, Health ssessment Questionnaire(HAQ) ≥0.25), despite 2 additional immunosuppressive treatments on top of glucocorticoids.

Exclusion Criteria:

1. Pregnancy or lactation,
2. Malignancy
3. Functional class 4
4. Contraindication to Maraviroc.

all IPD that underlie results in a publication