Background: Recombinant interleukin (IL)-11 is a thrombopoietic growth factor. The purpose of this study was to assess the toxicity, safety and efficacy of low-dose recombinant IL-11 in patients with bone marrow failure (BMF).
Patients and methods: Patients with BMF due to myelodysplastic syndromes (MDS), graft failure, chemotherapy or aplastic anemia (AA) were treated. Patients were required to have a platelet count of <20 x 10(9)/l, or a platelet count of <50 x 10(9)/l with an absolute neutrophil count <1 x 10(9)/l, or a hemoglobin value <10 g/dl. Treatment consisted of daily IL-11 at a dose of 10 mug/kg subcutaneously followed by a 2-week rest period. Two induction courses were given. Responders could receive maintenance therapy.
Results: Thirty-three patients (MDS, n=14; AA, n=16; prolonged thrombocytopenia following stem cell transplantation or chemotherapy, n=3) were evaluable. Their median age was 58 years (range 5-85). Three patients (9%) had poor risk cytogenetics. Nine patients (27%) responded to IL-11 (six MDS, three AA). Of these, three patients treated with IL-11 alone (n=1) or IL-11 together with other growth factors (n=2) showed multilineage recovery. The median time to response was 0.9 months (range 0.3-11). Factors associated with higher response rates in univariate analysis were age >50 years (P=0.008), diagnosis of MDS versus AA (P=0.025) and creatinine level >1 mg/dl (P=0.0004). The median response duration was 3 months (range 1.4-34.5+). Amongst responders, the median increment in platelet count was 111 x 10(9)/l (range 43-165). The most common side-effects were grade 1-2 lower extremity edema, conjunctival injections and fatigue. Grade 3 toxicities included arrhythmia (n=1) and transient ischemic attack (n=1). Ten patients (30%) had no side-effects.
Conclusions: Low-dose IL-11 has activity in patients with BMF and is generally well tolerated.