Platelet count over time in patients with positive binding or neutralizing transient vs persistent anti-romiplostim antibodies (A, C) or anti-TPO antibodies (B,D). The platelet count was evaluated for patients with positive transient or persistent anti-romiplostim or anti-TPO antibodies at week 1, a week before and a week after an antibody-positive result, and at the end of treatment. *Transient: negative result at the patient’s last time point tested. ^†Persistent: positive result at the patient’s last time point tested.