Imatinib in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs and widespread vasculopathy. Patients with SSc are classified according to the extent of cutaneous sclerosis: patients with limited SSc have skin thickening of the face, neck, and distal extremities, while those with diffuse SSc have involvement of the trunk, abdomen, and proximal extremities as well. The disease course varies depending on the subtype of SSc. However, common features that result in significant morbidity and mortality, in addition to cutaneous fibrosis, include Raynaud's phenomenon and digital ulcerations, interstitial lung disease (ILD), and pulmonary arterial hypertension (PAH). Current therapeutic options for patients with SSc and these clinical manifestations have shown limited efficacy. Imatinib antagonizes specific tyrosine kinases that mediate fibrotic pathways involved in the pathogenesis of SSc, including c-Abl, a downstream mediator of transforming growth factor (TGF)-beta, and platelet derived growth factor (PDGF) receptors. The efficacy of imatinib has also been reported in the treatment of patients with refractory idiopathic PAH through its effects on vascular remodeling. Based on the mechanism of action and preliminary patient data, we hypothesize that imatinib may be effective in the treatment of the fibrotic and vasculopathic features of patients with SSc. This is an open label pilot study to evaluate the safety and efficacy of imatinib in patients with progressive SSc refractory to other treatment(s). Validated measures of skin thickness and disease activity will be determined over 6-months of therapy and compared with baseline measures.