Treatment of Paget's disease of bone with intravenous 4-amino-1-hydroxybutylidene-1,1-bisphosphonate.

4-amino-1-hydroxybutylidene-1,1-bisphosphonate (AHButBP) was given intravenously (2.5-25 mg/day for 4 days) to 14 patients with Paget's disease of bone, five of whom had been treated with dichloromethylidene bisphosphonate (C12MBP) 32 months earlier. In the nine patients who had not been treated previously with bisphosphonates, the short course of AHButBP induced a suppression of serum alkaline phosphatase and urinary hydroxyproline values down to 30% of initial values. The biochemical suppression of the disease was sustained for 2-18 months and the time to relapse did correlate to the logarithm of the dose (P less than 0.001). In the five patients previously treated for Paget's disease, an apparent resistance to treatment with AHButBP was observed. However, in these patients both serum alkaline phosphatase and urinary hydroxyproline fell to or even below the nadir values which had previously been achieved with C12MBP, irrespective of the degree of relapse. Thus the degree of suppression of Paget's disease of bone, achievable after treatment with bisphosphonates, seems to be constant for each patient, such that normal levels of serum alkaline phosphatase and urinary hydroxyproline cannot usually be attained in patients with extremely active disease.