Treatment of inclusion body myositis with cyclosporin-A or tacrolimus: successful long-term management in patients with earlier active disease and concomitant autoimmune features.

OBJECTIVE

Sporadic inclusion body myositis (s-IBM) is a chronic, progressive, inflammatory myopathy of unknown aetiology, generally resistant to immunosuppressive therapy. Given that lymphocyte infiltrates in s-IBM muscle tissue are CD8+ T cells, targeting these cells may represent a valid approach.

PATIENTS AND METHODS

Three patients with biopsy-proven s-IBM, high creatine kinase levels at diagnosis, two of whom with associated immune disorders, were treated with either cyclosporin-A (CyA) or tacrolimus, in combination with high doses of corticosteroids (CS), followed by rapid CS tapering. Clinical assessment and laboratory evaluation were performed every three months for the first year and then every six months for the second year.

RESULTS

Based on muscle strength assessment and muscle enzyme serum levels, a major clinical response was observed at month +3 in two out of the three patients. A complete clinical response and major clinical response were obtained at month +6, in two and one patient, respectively. Normalization of serum muscle enzymes was observed in all. Steroids could be tapered to very low doses in all patients and were suspended early in one. Laboratory, but not clinical relapse occurred in one patient and was controlled by increasing the CyA dose. Treatment was well tolerated, with no serious adverse events occurring. All three patients are maintaining immunosuppressive therapy.

CONCLUSION

Calcineurin inhibitors may represent a useful option for the long-term management of s-IBM, possibly in a subset characterized by a short duration with high disease activity or associated autoimmune manifestations.