Pilot Study of Imatinib Mesylate to Treat Nephrogenic Systemic Fibrosis

Nephrogenic systemic fibrosis (NSF) is a recently described, extremely debilitating and painful condition that affects individuals with renal failure. Recent reports suggest an association between gadolinium exposure during magnetic resonance (MR) studies and the subsequent development of NSF in patients with chronic renal failure. NSF is characterized by rapidly progressive skin hardening, tethering and hyperpigmentation, predominantly on the extremities. Visceral involvement is rare. Skin biopsies of early NSF lesions demonstrate thickened collagen bundles, mucin deposition, angiogenesis and numerous dermal spindle cells that stain with antibodies to cluster of differentiation 34 (CD34) and procollagen. Cutaneous changes of NSF are present in up to 13% of individuals receiving hemodialysis. Among those patients with clinical evidence of NSF, the principle investigator of this protocol has recently reported that NSF is associated with increased early mortality at 24-months. There is no proven therapy for this devastating disorder. Anecdotal reports have shown modest improvement in joint mobility and decreased skin thickening with extracorporeal photopheresis and pentoxyphylline. Increased transforming growth factor (TGF)-beta1 messenger ribonucleic acid (mRNA) on immunostaining has been observed in skin, fascia and striated muscle. Imatinib mesylate, a tyrosine kinase inhibitor, prevents TGF-beta-induced stimulation of collagen and extracellular matrix protein synthesis as well as mRNA expression by normal fibroblasts. This observation led the principal investigator to evaluate imatinib mesylate 400 milligrams (mg) orally (p.o.) daily for 1 year in two participants with NSF. The result was significant softening of previously hardened skin with increased mobility of skin that previously had been tethered to the underlying fascia. After one month of imatinib mesylate, one of the two participants had a 20 degree reduction of his knee flexion contractures.