- Stable myositis disease activity will be defined by physician global and patient/parent global VAS that are <4 cm, as well as creatine kinase (CK), lactate dehydrogenase (LDH), aldolase, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) that are less than or equal to 2X upper limit of normal (ULN).