Chronic myelogenous leukemia: recent developments in prognostic evaluation and chemotherapy. The German CML Study...

Recent developments in CML research are illustrated by the results of one large randomized multicenter study carried out by the German CML Study Group. From July 1983 to January 1991, a total of 703 CML patients were recruited; 624 patients were randomized to compare hydroxyurea and interferon alpha (IFN) with busulfan. The median survival of Ph+ patients by now is 3.95 years, that of Ph- patients 1.1 years. Some difference in survival is recognizable between the treatment arms, but this is not yet significant. Fewer adverse effects are being observed in the hydroxyurea group. Ph-negative patients tend to have lower white blood cell and platelet counts. Patients (164) were randomized to receive IFN. In 50 patients (30%) IFN had to be terminated because of adverse effects, therapy resistance, or other reasons. Reduction of the Ph-chromosome was observed in 20% of evaluable patients. In 3 patients complete cytogenetic remissions were observed. Clinically relevant neutralizing antibodies were detected in 9 cases. Prospectively evaluated age, organomegaly related symptoms, Karnofsky index, extramedullary manifestations, erythroblasts, and percent of circulating blasts proved to be of prognostic significance. A prognostic score (score 1) was determined and compared to Sokal's score. It is expected that the study results will allow statements as to the advantages or disadvantages of the use of busulfan, hydroxyurea and IFN in the treatment of CML as well as to the reliability of prognostic markers.