IS THERE A ROLE FOR INTERLEUKIN-3 IN DIAMOND-BLACKFAN ANEMIA - RESULTS OF A EUROPEAN MULTICENTER STUDY

Forty patients (nine adults aged 20-54; 31 children aged 1-17) with Di amond-Blackfan anaemia (DBA) were treated with recombinant human inter leukin-3 (IL-3) in a European multicentre compassionate-need study. IL -3 was given as a daily subcutaneous injection at a starting dose of 2 5 mu g/kg, escalating at day 21 to 5 mu g/kg, and then to 10/mu g/kg i f there was no response, for a total duration of 12 weeks. Three child ren achieved a significant response, achieving sustained remissions of f all therapy. At the time of entry, one was steroid-responsive and tr ansfusion-independent, and two were transfusion-dependent. Two adults had a transient reduction in transfusion requirements, but could not t olerate the complete course of therapy. Eosinophilia was common; neutr ophil and platelet counts were unaffected except in three patients in whom previously noted mild thrombocytopenia was transiently exacerbate d. Clinical response to IL-3 did not correlate with in vitro culture r esults. A comparison of individual patient characteristics of our stud y with previously reported series confirms earlier impressions that pa tients who have never achieved significant in vive erythropoiesis in r esponse to steroids or during a spontaneous remission ate highly unlik ely to respond to IL-3. In contrast, there may be a 50% chance of a su stained remission, off steroids, in children who are steroid-dependent and transfusion-independent at the time of IL-3 therapy, suggesting a possible role for a short course of IL-3 earlier in the treatment of children with steroid-responsive DBA.