Effect of romiplostim on median platelet counts on day 1 of each treatment cycle (left panel) and on median platelet counts at nadir during each treatment cycle (right panel). P values in a nonparametric test comparing median platelet counts between the romiplostim 500-μg and placebo groups were 0.4233, 0.8389, 0.8389, and 0.8137 on day 1 of cycles 1, 2, 3, and 4, respectively, and 0.4986, 0.2905, 0.2905, and 0.5093 at the nadir of cycles 1, 2, 3, and 4, respectively. P values comparing median platelet counts between the romiplostim 750-μg and placebo groups were 0.8445, 0.2289, 0.0373, and 0.1198 on day 1 of cycles 1, 2, 3, and 4, respectively, and 0.3408, 0.2289, 0.0035, and 0.3833 at the nadir of cycles 1, 2, 3, and 4, respectively.