Beneficial effects of aminohexane diphosphonate in patients with Paget's disease of bone resistant to sodium etidronate.

Clinical and biochemical resistance to sodium etidronate therapy is not rare in patients with severe Paget's disease of bone, especially after several courses of treatment. Sixteen patients with Paget's disease of bone and well-documented resistance to sodium etidronate were treated with a new diphosphonate, aminohexane diphosphonate, given orally for three months at a daily dose of 400 mg. These patients comprised a selected population of patients with very active disease, as shown by a mean 20-fold increase of serum alkaline phosphatase levels before aminohexane diphosphonate therapy. Aminohexane diphosphonate induced a striking reduction of serum alkaline phosphatase and urinary hydroxyproline levels sustained for up to 18 months after withdrawal of treatment. Two patients had a relapse 14 to 16 months after treatment, and received a second course of aminohexane diphosphonate with the same efficacy. This was accompanied by marked clinical improvement, a reduction of the radioisotope uptake by pagetic bones, and radiologic healing of osteolytic lesions in some cases. Iliac crest biopsy specimens taken after tetracycline double-labeling showed no impairment of bone mineralization. No clinical or biochemical adverse effects have been observed.