The Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of HMPL-523 in Adult Subjects With Immune Thrombocytopenia (ITP)

Inclusion Criteria: Subjects may be enrolled in this study only if they satisfy all the following criteria: 1. Adult male or female subjects ≥18 years of age 2. Diagnosis of ITP, with a duration of disease of at least 3 months prior to randomization or enrollment 3. Intolerance or insufficient response or recurrence after at least 1 prior ITP treatment (excluding splenectomy) 4. Response (defined as achieved a platelet count ≥50 × 109/L) to at least 1 prior ITP therapy (including splenectomy) 5. Adequate hematologic, hepatic and renal function Exclusion Criteria: Subjects are not eligible for enrollment into this study if any one of the following criteria are met: 1. Evidence of the presence of secondary causes of ITP 2. Clinically serious hemorrhage requiring immediate adjustment of platelets 3. Known history of vital organ transplantation or hematopoietic stem-cell transplantation or chimeric antigen receptor T-cells (CAR-T) therapy 4. Splenectomy within 12 weeks prior to enrollment 5. Presence of active malignancy unless deemed cured by adequate treatment. 6. History of serious cardiovascular disease corrected QT interval (QTcF) ≥450 ms 7. Uncontrolled hypertension 8. Being unsuitable to participate in this study as considered by investigators