Phase II study of low-dose interleukin-11 in patients with myelodysplastic syndrome

Severe thrombocytopenia places patients with myelodysplastic syndrome (MDS) at risk of serious hemorrhage. Currently, therapeutic options are limited to platelet transfusions. The only commercially available growth factor that increases platelet counts is interleukin-11 (IL-11). We report the results of a phase II trial to more accurately assess the clinical response and toxicity data for low-dose IL-11 (10 mu g/kg/day) in patients with MDS. In this study, nine of 32 assessable patients (28%) demonstrated increases in their platelet counts after treatment. Of these, five were considered major platelet responses (15%), as defined by World Health Organization criteria. Four patients had minor platelet responses (13%). The median duration of platelet response was 9 months. Low-dose IL-11 was well tolerated, with no observed grade 4 toxicities. Our study provides additional clinical evidence that chronic administration of IL-11, at low doses, can raise platelet counts and reduce platelet transfusion requirements in a subset of patients with MDS.