The efficacy of PN-101 in subjects with polymyositis or dermatomyositis will be evaluated at Week 12 using IMACS-TIS in comparison with the placebo control group. The safety and efficacy will be evaluated following administration of PN-101 to subjects with polymyositis or dermatomyositis, in comparison with the placebo group
Adult aged 19 years or more
Clinical profile: Slowly progressing clinical profile with symmetrical and apparent muscular weakness confirmed at the proximal muscle (in case of dermatomyositis, clinical findings related with characteristic skin symptoms*)
Gottron's papules or sign, erythema purpura, poikiloderma, calcinosis cutis, etc.
Serum test: Serum creatine kinase (CK) elevated (CK ≥ 1.3 × upper limit of normal (ULN)) or serum myositis-specific antibodies (MSA) positive
A subject with clear muscular damage, with the VAS-based myositis damage index (MDI) of ≥ 5 at screening
A subject with the following medical history or surgical history
A surgical operation history within 12 weeks of screening
Malignant tumor within 5 years of screening (excluding a subject who passed 3 years or more from complete recovery of cervical cancer or skin squamous cell carcinoma)