Successful treatment of diamond‐blackfan anemia with interleukin 3

This report describes the response of 18 Diamond‐Blackfan anemia (DBA) patients to recombinant human interleukin 3 (rhIL‐3). rhIL‐3 was administered s.c. once daily on an escalating dose schedule (0.5–10 m̈g/kg/day). The rhIL‐3 dose was escalated every 21 days until erythroid response was attained, grade III or IV nonhematologic toxicity was observed, or the maximal rhIL‐3 dose was reached. Four patients experienced clinically significant erythroid responses. Two of the responders were steroid‐dependent and transfusion‐independent, while two were steroid‐independent and transfusion‐dependent. Baseline clinical or laboratory parameters, in particular in vitro bone marrow erythroid progenitor assays, were not useful in predicting rhIL‐3 response. Two of the responding patients remain on maintenance rhIL‐3 without diminution of effect at 490 and 855+ days. rhIL‐3 was discontinued in the other two responders because of the development of deep venous thrombi.