7009 Background: Thrombocytopenia is common in patients (pts) with MDS, and treatment options are currently limited to platelet (plt) transfusions. Romiplostim is an Fc-peptide fusion protein (peptibody) that stimulates plt production by the same mechanism as thrombopoietin.
METHODS
This was a phase II, multicenter, single arm, open-label study. Eligibility criteria included IPSS low or intermediate-1 risk MDS and a mean baseline plt count ≤50x109/L. Safety and efficacy of romiplostim were evaluated in pts receiving 750μg romiplostim according to one of 3 schedules: weekly or biweekly subcutaneous injections (QWSC or Q2WSC), or biweekly intravenous injections (Q2WIV). Plt responses were measured per IWG 2006 criteria.
RESULTS
Of the 28 pts enrolled, 17 (61%) completed the study; 22 (79%) were male and the mean (±SD) baseline plt count was 29 (±10) x 109/L. The mean age was 71 years and 19 pts (68%) had received plt transfusions in the past year. Mean duration of exposure to romiplostim was 12 (±8) weeks. The most common adverse events (AEs) were fatigue and headache (both 18%). Five pts experienced serious AEs, and there were 2 cases of disease progression to AML: one pt in the QWSC cohort who received romiplostim for 4 weeks and one in the Q2WSC cohort who received romiplostim for 20 weeks. For pts who completed 8 weeks treatment, 15/23 (65%) achieved a plt response, defined by IWG 2006 criteria, and 14/23 (61%) did not require a plt transfusion during this period. The small number of pts limited the ability to compare administration schedules; minor differences were observed in plt responses and plt transfusions, and the incidence of AEs appeared similar among cohorts.
CONCLUSIONS
IV and SC romiplostim appeared well-tolerated and effective in raising plt counts and avoiding plt transfusions in low and intermediate-1 risk MDS pts. The dose recommendation for future studies is 750μg, given QW or Q2W SC. [Table: see text] [Table: see text].