Long-term benefit from prednisone therapy in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a genetic disorder in which the inherited absence of a muscle protein results in the progressive deterioration of muscle strength and eventual death. Research studies have suggested that the downward course of the illness may be slowed significantly by treatment with steroid drugs. In a previous study, it was not only demonstrated that prednisone was superior to placebo in maintaining muscle strength, but also that a daily dose of prednisone was superior to treatment every other day. When these findings became conclusive, 92 boys participating in the study were all placed on daily prednisone therapy. The results from two years of treatment (three, if counting the previous experimental period) now indicate that the steroid therapy has significantly slowed the progression of DMD. Data at the end of three years may indicate that improvement was related to several factors. The boys experienced an increase in muscle strength when they began prednisone treatment; it is possible that this temporary increase gave them an advantage, and that the rate of decline after the first six months has been about the same. Regular measurements of muscle strength and performance indicate that this is not the case. The boys experienced an increase in muscle strength which peaked by six months. However, the decline in muscle strength thereafter occurred at a slower rate than is generally observed among patients with DMD. Indeed, the expected annual decline in muscle performance scores is almost five times greater than the decline that has been observed among the prednisone-treated patients. These results confirm that prednisone slows the progression of DMD for at least three years. The benefits of prednisone must be weighed against the side effects of steroid treatment, which include weight gain and the typical puffiness of the skin. (Consumer Summary produced by Reliance Medical Information, Inc.)