Duchenne muscular dystrophy (DMD) is a rare disease that affects about 1 in 3500 to 1 in 6000 boys. Patients suffer from progressive muscle wasting, respiratory and cardiac impairments and premature death. Currently, only symptomatic treatment with glucocorticoids is available; these have limited efficacy but many adverse effects.
Tamoxifen (TAM) is a selective estrogen receptor modulator and has been used for more than 35 years to treat estrogen receptor positive breast cancer. In adults it is usually given at a dose of 20mg per day. There is abundant safety information on the use of TAM in adults and adolescents but less on pre-pubertal children.