A Randomized, Double-Blind, Placebo-Controlled Phase 2 Clinical Study to Evaluate the Safety and Efficacy of SG301 SC Injection in Patients With Primary Immune Thrombocytopenia
This is a multicenter, randomized, double-blind, placebo-controlled Phase II clinical study. The primary objective is to evaluate the safety and efficacy of SG301 SC Injection in participants with ITP, while the secondary objectives are to assess the pharmacokinetic, pharmacodynamic and immunogenicity profiles of SG301 SC Injection in ITP participants. A total of 60 ITP participants are planned to be enrolled in this study and randomly assigned at a 1:1:1 ratio to the low dose group, high dose group and placebo group, with approximately 20 participants per group. All participants enrolled in this study may receive concomitant background therapies at stable doses for at least 4 weeks prior to the first study drug administration, and is expected to be maintained throughout the study period.
• Aged 18-75 years, any gender.
• Voluntarily signed informed consent and able to comply with study procedures.
• Clinically diagnosed with primary immune thrombocytopenia (ITP) per 2019 ASH Guidelines, international consensus statements, or 2025 Chinese Guidelines for Adult ITP Diagnosis and Treatment; disease duration ≥ 3 months.
• Experienced treatment failure or relapse after prior first-line therapy (glucocorticoids and/or IVIG).
• ≥2 platelet assessments ≥3 days apart before first dosing: mean platelet count \<30×10⁹/L, no single value \>35×10⁹/L.
• ECOG performance status 0-2.
• On stable-dose maintenance therapy for ≥4 weeks pre-first dose, with stability expected throughout the trial.
• Screening lab parameters meeting criteria below:
‣ Liver function: AST and ALT ≤3×ULN; total bilirubin ≤1.5×ULN.
⁃ Renal function: eGFR ≥30 mL/min (CKD-EPI equation).
⁃ CBC (no RBC transfusions, IL-11, EPO or colony-stimulating factors within 2 weeks before testing): hemoglobin ≥90 g/L, absolute neutrophil count ≥1.5×10⁹/L.
• Participants or partners with childbearing potential must use effective contraception during the study and for 6 months after last study drug administration.