Treatment of advanced myelodysplastic syndromes with recombinant interferon-alpha 2b.

We examined the efficacy and toxicity of recombinant interferon-alpha 2b (rIFN-alpha 2b) in 10 previously untreated patients with advanced myelodysplastic syndromes. Morphological subtypes were refractory anaemia with excess of blasts (RAEB) in 4, RAEB in transformation (RAEB/T) in 3 and chronic myelomonocytic leukaemia (CMML) in 3 cases. IFN was administered subcutaneously at increasing doses of 1 to 3 x 10(6) IU per day. The median duration of therapy was 6 months (range, 3 to 14). 2 patients, both with a diagnosis of CMML, achieved a complete and partial remission, respectively. In the complete responder, remission could be maintained for 9.5 months by daily administration of 1 x 10(6) IU IFN. The other patients were classified as failures, although in 4 cases a decrease of bone marrow blasts was noted and none of the patients progressed to overt leukaemia while being treated with IFN. During the study, all patients with RAEB and RAEB/T showed a moderate to severe reduction in peripheral leukocyte and platelet counts, requiring premature termination of IFN therapy in 5 cases. Despite adequate supportive measures, 2 patients died of pneumococcal pneumonia and gastrointestinal bleeding, respectively. In 1 patient, IFN therapy had to be stopped because of neurologic toxicity (polyneuropathy). From these data we conclude that rIFN-alpha 2b at the doses and schedule tried is not a useful treatment for advanced myelodysplastic syndromes. Patients with CMML, however, may be an exception and should further be considered as candidates for therapeutic trials with rIFN-alpha 2b.