Rituximab for Treatment of Systemic Sclerosis-Associated Pulmonary Arterial Hypertension (SSc-PAH)

"Participants receive rituximab intravenous (IV) infusions, 1000 mg each, 14 days apart (Day 0 and Week 2).~Rituximab is supplied as a sterile, clear, colorless, preservative-free liquid concentrate for intravenous (IV) administration in either 100 mg (10 mL) or 500 mg (50 mL) single-use vials, which must be diluted before administration~Standard rituximab pre-medications will be provided in preparation for the rituximab infusions."

"Participants receive placebo intravenous (IV) infusions 14 days apart (Day 0 and Week 2).~Standard pre-medications will be provided in preparation for the infusions."

Up to 20 participants from each treatment arm will be assessed by CMRI at Baseline and at Week 24.

Prednisone dose of 40 mg (or equivalent) by mouth administered the night before and the morning of each study drug infusion.

Methylprednisolone (or equivalent corticosteroid) administered intravenously 30 minutes prior to each study drug infusion.

"Diphenhydramine 50 mg (or equivalent) administered by mouth approximately thirty to sixty minutes prior to each study drug infusion.~Dose may be repeated every four hours, as needed."

"Acetaminophen 650 mg (or equivalent) administered by mouth approximately thirty to sixty minutes prior to each study drug infusion.~Dose may be repeated every four hours, as needed."