Table 3.

Efficacy trials of antiplatelet therapies in SCD.

Study Design	Study Population	Intervention	Primary Outcome Measure and Result
Phase IIb Multicenter, double-blind, double-dummy, randomized, placebo-controlled, parallel-group [213]	● Have SCD [homozygous sickle cell (HbSS) or sickle beta-zero thalassemia (HbSβ0)] ● Ages 18–30 years (mean 22.2 years old) ● Have ≥4 days of pain during the 4-week single-blind placebo baseline period prior to randomization ● If on hydroxycarbamide, a stable dose for 3 months prior to enrollment required ● If on erythropoietin, drug must have been prescribed 6 months before and at a stable dose for ≥3 months prior to randomization (n = 194)	● Ticagrelor 10 mg plus matching placebo for ticagrelor 45 mg ● Ticagrelor 45 mg plus matching placebo for ticagrelor 10 mg ● Matching placebo for ticagrelor 10 and 45 mg Duration: 12 weeks	Proportions of days with diary-reported SCD pain No significant difference between placebo and ticagrelor treatment groups
Phase III Multinational, double-blind, randomized, placebo-controlled, parallel-group [212]	● Have SCD [homozygous sickle cell (HbSS) or sickle beta-zero thalassemia (HbSβ0)] ● Are participants with SCD who have had ≥2 episodes of vaso-occlusive crisis (VOC) in the past year ● Have a body weight ≥ 19 kilogram (kg) and are ≥ 2 and <18 years of age, inclusive at the time of screening ● If participants are ≥2 and ≤16 years of age, they must have had a transcranial Doppler within the last year (n = 341)	● Prasugrel 0.08–0.12 mg/kg po once daily ● Placebo Duration: 9–24 months	Number of Vaso-Occlusive Crisis (VOC) Events Per Participant Per Year (Rate of VOC) Terminated due to lack of efficacy
Phase III Double-blind crossover study [211]	● Have sickle hemoglobinopathy observed regularly ● Ages 2–17 years old (mean 7.7 years old) ● The hematologic diagnosis was confirmed by cellulose acetate electrophoresis at pH 8.6 and citrate agar electrophoresis at pH 6.4 ● At least 50% compliant (n = 49)	● Low dose aspirin ● Placebo	Frequency and severity of VOC No significant difference between placebo and aspirin treatment groups