To evaluate the safety and tolerability of escalating, single subcutaneous doses of MEDI7734 in adult subjects with type I interferon-mediated autoimmune diseases.

MEDI7734 is a human monoclonal antibody that binds to and causes temporary depletion of plasmacytoid dendritic cells (pDCs), a type of white blood cell. The objectives of this study are to evaluate the safety, drug levels, and pDC levels in subjects who are given a single injection of MEDI7734 or a placebo.

The study will be conducted in subjects with at least one of the five following autoimmune diseases: dermatomyositis, polymyositis, Sjogren's syndrome, systemic lupus erythematosus, or systemic sclerosis.

After a screening period, subjects will be randomized in a 3:1 ratio to receive a single dose of MEDI7734 or matching placebo, administered as a subcutaneous (under the skin) injection. After that, subjects will be evaluated periodically at the study site over at least the next 85 days.

Study acquired from Horizon in 2024. Originally Viela Bio was the sponsor.

Key Inclusion Criteria:

1. Age 18-65 years old
2. Diagnoses of dematomyositis, polymyositis, Sjogren's syndrome, systemic lupus erythematosus and/or systemic sclerosis based on standard criteria.
3. Weight 40-120kg
4. Stable disease such that in the opinion of the investigator it is unlikely that a change in subject's therapeutic regimen would be required during the subsequent 3 months.

Key Exclusion Criteria:

1. History of a hypersensitivity reaction or anaphylaxis to a previous mAb or human immunoglobulin therapy.
2. Chronic hepatitis B, chronic hepatitis C, or HIV infection.
3. History of latent or active tuberculosis (TB), or a positive QuantiFERON®-TB Gold test at screening.
4. Herpes zoster infection within 3 months before randomization
5. Any of the following medications within 6 months of Day 1: cyclophosphamide, leflunomide > 20 mg/day, abatacept.
6. Receipt of a mAb within 5 published half-lives prior to Day 1.
7. Receipt of rituximab or an experimental B-cell depleting mAb within 6 months of Day 1.
8. Receipt of rituximab or an experimental B-cell depleting mAb without return of CD19 or CD20 count to above the lower limit of normal.
9. Receipt of alemtuzumab, bone marrow transplantation, stem cell transplantation, total lymphoid irradiation, or T-cell vaccination therapy -

AstraZeneca's policy is to share data with researchers if the request is in scope of our policy. Additional information can be found on astrazenecaclinicaltrials.com.