A Study to Understand How Nerandomilast Works in People With Active Idiopathic Inflammatory Myopathies

This study is open to adults aged 18 and older who have a condition known as activeidiopathic inflammatory myopathy (IIM) or myositis. People can participate if they have aspecific type of myositis. The purpose of this study is to find out whether a medicinecalled nerandomilast improves IIM symptoms.Participants are put into 2 groups randomly, which means by chance. One group takesnerandomilast tablets and the other group takes placebo tablets. Placebo tablets looklike nerandomilast tablets but do not contain any medicine. Participants takenerandomilast or placebo twice a day for 1 year.Participants are in the study for about 1 year and 2 months. During this time, they visitthe study site at least 16 times. During this time, doctors regularly check theparticipant's health, IIM symptoms, and take note of any unwanted effects. Participantsfill in questionnaires about their IIM symptoms and how IIM impacts their quality oflife. The results are compared between the 2 groups to see whether the treatment works.