Inclusion Criteria:

Inclusion Criteria for the MAD Stage:

- Diagnosis of SSc, as defined by 2013 American College of Rheumatology (ACR)/European
League Against Rheumatism (EULAR) criteria and ≤ 10 years disease duration.

- Participants with diffuse cutaneous systemic sclerosis (dcSSc), ≥ 15 modified Rodnan
Skin Score (mRSS) units or with limited cutaneous systemic sclerosis (lcSSc), ≥ 9 mRSS
units.

- Agreement to remain abstinent or use an effective contraceptive method among males and
females with childbearing potential.

Inclusion Criteria for the OSE Stage:

- No clinically significant change in eligibility status.

- Completion of the MAD and ability to roll over into the OSE within 72 hours.

Exclusion Criteria:

- Active rheumatic autoimmune disease other than SSc requiring treatment with
disease-modifying therapy.

- Pulmonary disease with forced vital capacity (FVC) ≤ 50% of predicted.

- History or clinical manifestations of significant metabolic, hepatic, renal,
pulmonary, cardiovascular, hematologic, gastrointestinal, urologic, neurologic, or
psychiatric disorders.

- History of severe allergic or anaphylactic reactions to human, humanized, or murine
monoclonal antibodies.

- Immunization with a live/attenuated vaccine within 4 weeks prior to initiation of
study drug or planned during study.

- Pregnant or breastfeeding, or intending to become pregnant during the study or within
4 months after the final dose of study drug.

- History of solid organ or stem-cell transplantation.

- Major surgery within 8 weeks prior to screening, or major planned surgery during the
study or within 3 months after the final dose.

- Positive hepatitis C virus (HCV) antibody, hepatitis B surface antigen (HBsAg), or
human immunodeficiency virus (HIV) antibody test at screening.

- Serious infection requiring oral or intravenous (IV) antibiotics within 14 days prior
to initiation of study drug or IV antibiotics within 28 days prior to initiation of
study drug.

- Any serious medical condition or abnormality in clinical laboratory tests.

Eligibility last updated 10/13/22. Questions regarding updates should be directed to the study team contact.