Histiocytosis X: clinical trial of chlorambucil: a report from Childrens Cancer Study Group

A prospective study for histiocytosis X was designed to determine whether "good risk" patients, ie, those without evidence of dysfunction of liver, lung, or hemopoietic system, would respond to single agent therapy; in this case chlorambucil (CMB) used in a dose of 5 mgm/m2/day. If there was no response after an adequate trial period, treatment was initiated with four drugs using a combination of prednisone, vinblastine, cyclophosphamide and methotrexate. There were 26 evaluable patients, 57% of whom were less than two years of age at onset of therapy. There were three complete and four partial responses to CMB for a response rate of 26.9%. Sixteen patients received an adequate trial of four-drug therapy with three complete and two partial responses for a response rate of 33%. These responses were inferior to those previously reported for either single agents or combined therapy in histiocytosis X.