Dataset from A Randomized, Double-Blind, Placebo-Controlled, Phase II Multicenter Trial of a Monoclonal Antibody to CD20 (Rituximab) for the Treatment of Systemic Sclerosis-Associated Pulmonary Arterial Hypertension (SSc-PAH)

Systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) is a serious,
life-threatening manifestation of systemic sclerosis (SSc), an autoimmune disease of the
connective tissue characterized by scarring (fibrosis) and atrophy of the skin, joints and
tendons, skeletal muscles, and internal organs, and immunological disturbances. One-year
survival for patients with SSc-PAH ranges from 50-81%. There is currently no cure for SSc-PAH
and treatment is limited to vasodilator therapy used in all forms of PAH. In recent studies,
immunotherapy was shown to be effective in treating SSc-interstitial lung disease, another
serious, life-threatening manifestation of SSc. In addition, there are compelling
pre-clinical data and anecdotal clinical reports that suggest modulation of the immune system
may be an effective strategy for treating SSc-PAH. To test this approach, this trial will
determine if rituximab, an immunotherapy, has a marked beneficial effect on clinical disease
progression, with minimal toxicity, in patients with SSc-PAH when compared to placebo.