Subject Disposition The median follow-up time for patients in the Core study and Extension phase is 10.4 months (range: 0.8-25.6 months; ongoing). To date, 97% of patients who have completed the Core study have continued into the Extension phase. During the Core study, 32 patients (19%) have discontinued the study, five for possibly or probably related adverse events, for a current overall retention rate of 81%. The retention rate during the Extension phase is currently 79%.
Anemia Response Of the 68 patients who were transfusion dependent at baseline, to date 54% have become transfusion independent for a minimum of 12 weeks. The median duration of the transfusion-free period has not yet been reached (range: 82-506 days, ongoing). More than 25% of subjects who were not receiving transfusions while on study experienced at least a 1 g/dL increase in hemoglobin lasting for more than eight weeks.
Of the 26 patients who were dosed at 300mg QD and were transfusion dependent at baseline, to date 65% have become transfusion independent for a minimum of 12 weeks.
Spleen Response Of the 142 patients evaluable for spleen response, 31% achieved a response per IWG-MRT*. The median duration of spleen response has not yet been reached (range: 55 - 574 days, ongoing). The median time to spleen response was 15 days (range: 6 - 260 days, ongoing). To date, 49% of patients achieved more than a 50% maximal decrease in spleen size from baseline, with 87% achieving more than a 25% maximal decrease.Of the 51 patients who were dosed at 300mg QD and were evaluable for spleen response, 33% achieved a response per IWG-MRT. Eleven patients were evaluable for spleen response both by MRI and by palpation. The response rate was 64% by MRI (defined as a 35% decrease in spleen volume) and 45% by palpation (defined as a 50% decrease in spleen length). The median splenic decrease from baseline at three months was -41% by volume measured by MRI and -45% by length measured by palpation.