Early Use of Realgar-Indigo Naturalis Formula (RIF) Combined With All-trans Retinoic Acid (ATRA) for Treating Acute Promyelocytic Leukemia (APL).

Study Title: Multicenter, Randomized Controlled Clinical Study on Early Application of Realgar-Indigo Naturalis Formula (RIF) for Treatment of Acute Promyelocytic Leukemia (APL) Sponsor: Xi'an Jiaotong University First Affiliated Hospital Principal Investigator: Wang Huaiyu Study Description: This multicenter, randomized controlled trial evaluates whether early induction treatment with oral Realgar-Indigo Naturalis Formula (RIF) combined with all-trans retinoic acid (ATRA) reduces early death rates in patients with acute promyelocytic leukemia (APL). APL is a subtype of acute myeloid leukemia characterized by a high risk of early death, largely due to coagulopathy and bleeding events, especially in high-risk patients with elevated white blood cell counts. Traditional treatment with ATRA and arsenic trioxide (ATO) has improved outcomes but early mortality remains a major challenge. RIF, an oral arsenic compound Chinese patent medicine, has demonstrated efficacy comparable to ATO with advantages in safety and oral administration convenience. Previous smaller studies suggested RIF may accelerate recovery of coagulation parameters and reduce early death. Patients clinically suspected of APL will be randomized into two groups: Experimental group: oral ATRA + RIF before molecular diagnosis confirmation Control group: oral ATRA only before confirmation After molecular or genetic diagnosis confirmation: Experimental group receives 1 week of ATRA + RIF induction (days 0-7), then switches to 3 weeks ATRA + ATO (days 8-28) Control group receives 4 weeks ATRA + ATO (days 0-28) Both groups then receive identical consolidation therapy with ATRA + ATO for 6 cycles (2 weeks treatment + 2 weeks off per cycle) following molecular complete remission. Primary Objective: To evaluate whether early induction with ATRA + RIF reduces early death rate (within 30 days of diagnosis) in APL patients. Secondary Objectives: To explore if early ATRA + RIF (prior to molecular confirmation) is non-inferior to ATRA alone in reducing coagulopathy and early death in suspected APL patients. Secondary endpoints include 2-year event-free survival (EFS) and overall survival (OS). Study Design: Type: Multicenter, randomized, open-label controlled clinical trial Population: Adults aged 18-80 years with newly diagnosed acute myeloid leukemia highly suspected as APL Randomization: Central randomization assigns participants to experimental (ATRA + RIF) or control (ATRA only) groups Blinding: Open-label (no blinding) Inclusion Criteria: Age 18-80 Newly diagnosed AML with strong clinical suspicion of APL based on bone marrow morphology and immunophenotyping Exclusion Criteria: Negative for PML-RARα fusion by cytogenetics or RT-PCR Severe organ dysfunction not related to APL (renal, hepatic, cardiac) QTc \>480 ms before treatment Other malignancies Pregnant or breastfeeding women Treatment Regimen: Induction: Experimental group receives oral ATRA 25 mg/m²/day + RIF 60 mg/kg/day for 7 days, then ATRA + intravenous ATO 0.15 mg/kg/day for 3 weeks; Control group receives ATRA + ATO for 4 weeks. Consolidation:During the consolidation phase, intermediate- and low-risk patients receive either intravenous ATO or oral RIF, while high-risk patients receive intravenous ATO together with intravenous mannitol infusion. Routine lumbar puncture and intrathecal chemotherapy are not performed. Supportive care includes hydroxyurea and venetoclax for elevated WBC, transfusions for coagulopathy, and dexamethasone for differentiation syndrome. Endpoints: Primary endpoint: Early death rate (death within 30 days of diagnosis) Secondary endpoints: 2-year event-free survival (EFS), 2-year overall survival (OS) Sample Size: Approximately 224 patients (112 per group), calculated to detect a reduction in early death rate from 12% (historical) to 3% (experimental), with 80% power and 5% significance level. Statistical Analysis: Descriptive statistics for baseline characteristics and adverse events Kaplan-Meier survival analysis for EFS and OS Significance threshold p \< 0.05 Safety Monitoring: Daily blood count and coagulation tests during induction Monitoring and management of adverse events including severe coagulation disorders, differentiation syndrome, arsenic toxicity, infection, and bone marrow suppression Adverse events graded with CTCAE criteria and reported accordingly Data Handling: Electronic data capture system compliant with ICH-GCP and CDISC standards Confidential storage at Xi'an Jiaotong University First Affiliated Hospital Data anonymized for reporting Ethics: Conducted in accordance with the Declaration of Helsinki and Chinese clinical research regulations Protocol approved by local ethics committee Written informed consent required before study enrollment Study Timeline: Planned start: June 2025 Planned completion: June 2028