Cyclosporin A in the treatment of refractory adult polymyositis/dermatomyositis: Population based experience in 6 patients and literature review

Objective. To evaluate the efficacy and toxicity of cyclosporin A (CSA) in the treatment of refractory adult polymyositis/dermatomyositis (PM/DM). Methods. The province-wide British Columbia database fur CSA use for person s with rheumatic dis eases at Mary Pack Arthritis Centre was reviewed to id entify all patients with PM/DM for the period January 1991 through June 199 8. Also, a Medline search of English language literature was conducted for this topic From 1976 until January 1999, using the terms dermatomyositis, p olymyositis, inflammatory myopathy, and cyclosporin A, and the reference li sts of all papers were screened to include articles not identified by the M edline search. Results. In British Columbia, 172 CSA users of whom 6 had PM/DM were identi fied (4 PM, 2 DM). Previous therapy included high dose prednisone (N = 6), methotrexate (N = 4), azathioprine (N = 4). intravenous immunoglobulin (N = 3), and cyclophosphamide (N = 3). The mean CSA dose was 3.5 mg/kg/day. All patients improved. Creatinine kinase (CK) levels declined 52% from baselin e. All 6 patients continued CSA a median of 6 months: (range 3-44 mo) after initiation of therapy. Toxicity included an increase in serum creatinine > 30% of baseline in 3 patients and hypertension in one patient. The literat ure review identified an additional 59 cases. Forty-eight (81%) had a reduc tion in CK levels and improved clinically, 9/59 (15%) developed nephrotoxic ity, 5/59 (8%) hypertension responsive to dose reduction, and 9/59 (15%) ha d hypertrichosis, gingival hyperplasia. or tremor Conclusion. Our population based experience with 6 patients and the 59 publ ished cases suggests CSA is an effective therapy for resistant PM/DM, and t oxicity is possibly more than expected in other rheumatic diseases.