Chronic myelogenous leukaemia: haematological remissions with alpha interferon.

Twenty-seven consecutive patients with previously untreated, or minimally treated benign phase Philadelphia-chromosome-positive, chronic myelogenous leukaemia (CML) were treated with partially purified human leucocyte (alpha) interferon; 24 of the 27 patients responded to therapy achieving either haematological remission (20 patients) or partial haematological remission (four patients). In the responding patients the peripheral white blood cells declined from a median of 89.6 X 10 X 10(9)/l to 4.5 X 10 X 10(9)/l. The serum lactate dehydrogenase declined from a mean of 8.36 Katal/l (492 mu/ml) to 2.8 Katal/l (165 mu/ml), and the vitamin B12 levels declined from 1492 pg/ml to 838 pg/ml. Fifteen patients had splenomegaly. The spleen size normalized in four and decreased by a median of 30% in 10 additional patients. The bone marrow cellularity fell from a median of 100% to a median of 62%. In seven of the 24 responding patients, followed for greater than or equal to 6 months, the percentage of Ph1-positive cells in the bone marrow declined to a median of 70% (range 5-75%). Alpha interferon was found to be an effective therapeutic agent for controlling the myeloid proliferation in CML, and in partially restoring the nonclonal haematopoietic cells in some of the patients.