Safety and Efficacy of ULSC on Disease Severity and Steroid Tapering in Participants With Dermatomyositis/ Polymyositis (DM/PM), Also Known as Idiopathic Inflammatory Myopathy (IIM)

Exclusion Criteria

• •7. Adequate pulmonary function, defined as saturated oxygen (SpO2 ≥ 94%) on room air.
• •8. Left ventricular ejection fraction (LVEF) ≥ 30% as assessed by echocardiogram (ECHO) or multigated acquisition (MUGA) scan performed within 8 weeks prior to Screening.
• •9. Participants must have the ability to comply with the requirements of the study.
• •10. All participants of reproductive age/capacity will be required to use adequate contraception, defined as at least one form of a highly effective contraceptive (i.e., condoms, hormonal birth control, IUD), with any partners during the study period and for at least three months beyond the study period, for safety.
• •11. Participant will have the ability to understand and provide written informed consent.
• •The presence of any of the following criteria excludes a participant from study enrollment:
• •1. A diagnosis of inclusion body myositis, juvenile DM or PM, myositis in the context of significant autoimmune rheumatologic disease.
• •2. Diagnosis of IIM as part of an overlap syndrome (except overlap with Sjogren's syndrome).
• •3. Initiation of Rituxan (rituximab) treatment within 12 weeks of randomization. If participant is already on Rituxan, they must remain on a stable dose throughout the trial.
• •4. Use of other biologic or investigational drug within 6 half-lives for the agent.
• •5. Diagnosis of myositis-associated interstitial lung disease or cardiac involvement sufficient to limit participation in the trial in the discretion of the PI.
• •6. End-stage IIM with irreversible muscle involvement seen on biopsy.
• •7. Patients with predominant muscle atrophy secondary to uncontrolled or chronic DM or PM, based on clinical, biochemical, and/or radiologic assessment, despite previous optimized treatment.
• •8. Non-immune myopathies.
• •9. Cancer associated with myositis.
• •10. Hypersensitivity to study product components including history of hypersensitivity to dimethyl sulfoxide (DMSO).
• •11. Pregnant or lactating participants.
• •12. Concomitant severe cardiac, pulmonary disease, active infection, or other conditions that preclude assessment of safety and efficacy of the study product.
• •13. Anticipated need for surgery during the trial period.
• •14. A history of prevalent noncompliance with medical therapy.
• •15. Recipient of an organ transplant.
• •16. Neutropenia \[absolute neutrophil count \<1,800/mm\^3 (or \<1,000/mm\^3 in African-American participants)\].
• •17. Severe impairment in renal function (estimated glomerular filtration rate \<30 ml/kg\*min).
• •18. Recent or planned use of vaccination with live attenuated viruses.
• •19. Active cancer or prior diagnosis of cancer within the past 2 years, except non-melanoma skin cancer and carcinoma in situ of cervix Potential participants diagnosed with IIM \<3 years before screening will have mandatory evaluation for cancer.
• •20. Participants with current or prior hepatitis B infection that could be at risk for reactivation. \[For eligibility, screening test results must be HBsAg (DNA) negative and anti-HBc (core antibody total) negative).\]
• •21. Participant with HIV or active Hepatitis C. \[For eligibility, the following screening tests must have negative or non-reactive results: HIV ELISA, HCV Ab with reflex for HCV RNA (PCR); if HCV Ab test is positive, exclude if HCV RNA (PCR) is positive.\]
• •22. Condition that would impair an assessment of muscle strength, including neurological disorders such as Parkinson's disease or severe musculoskeletal condition.
• •23. Any other condition that, in the judgment of the Investigator or Sponsor, would be a contraindication to enrollment, study product administration, or follow-up.