A Study of Imvotamab in Active, Refractory Idiopathic Inflammatory Myopathies

Key Inclusion Criteria:

• Age ≥ 18 years at the time of signing ICF

• Diagnosis of probable or definite IIM according to the 2017 European League AgainstRheumatism (EULAR)/American College of Rheumatology (ACR) classification criteriafor IIM with subgroup classification of either DM, polymyositis (PM),anti-synthetase syndrome, or immune-mediated necrotizing myositis (IMNM).

• Active IIM despite treatment with corticosteroids and at least 1 immunosuppressiveor immunomodulatory standard-of-care agent determined at the discretion of theinvestigator after at least 3 months of treatment.

• If using oral corticosteroids (OCS), must be on a stable dose equivalent to ≤ 30mg/day of prednisone for at least 4 weeks prior to first study treatment

Key Exclusion Criteria:

• Pregnant or breastfeeding or intending to become pregnant during the study or within 3 months after the final dose of imvotamab.

• Receipt of an investigational therapy less than 12 weeks or 5 drug-eliminationhalf-lives (whichever is longer) prior to first administration of study treatmentand during the study.

• Has inclusion body myositis or myositis-associated with other connective tissuedisease.