Phase 1/2 and extension trials. Mean percentage change of key clinical parameters. The mean percentage change in hemoglobin concentration, platelet counts, liver volume, and spleen volume is plotted across time and demarcated for both the phase 1/2 and extension studies. A statistically significant change from baseline is observed from baseline to 9 months (P < .003) and baseline to 48 months (P < .004) for each parameter. The most marked changes were observed for platelet count and spleen volume. Hemoglobin values normalized for all patients by 24 months. Liver volumes approached normal.