NCT07169565

Ibrutinib Followed by BR (Bendamustine and Rituximab) as a Time-Limited Therapy for Waldenström Macroglobulinemia

Phase I Clinical Study of Ibrutinib Followed by BR (Bendamustine and Rituximab) as a Time-Limited Therapy for Waldenström Macroglobulinemia

• Status: Not Yet Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 21 (estimated)
• Sponsor: Institute of Hematology & Blood Diseases Hospital, China · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

This is a two-part, non-randomized, open-label Phase I clinical study. The research consists of: 1. A 3+3 dose-escalation phase to determine the Maximum Tolerated Dose (MTD) and Recommended Phase II Dose (RP2D) of the I+BR regimen in Waldenström Macroglobulinemia (WM) patients; 2. A dose-expansion phase to evaluate the safety, tolerability, and efficacy of the time-limited regimen at the MTD/RP2D. Key Study Design Details: Pre-enrollment \& Eligibility: * Patients undergo efficacy and tolerability assessment before enrollment. * Eligible patients receive I+BR therapy. Treatment Regimen: * Bendamustine: Tested at three dose levels (70 mg/m², 60 mg/m², and 50 mg/m²) based on prior IBR data in B-cell lymphomas. A 3+3 dose de-escalation design is employed. * Fixed Doses: * Ibrutinib: 420 mg/day * Rituximab: 375 mg/m² Part I (3+3 Dose Escalation): * Start with 3 patients receiving bendamustine 70 mg/m². * After 1 treatment cycle: * Assess Dose-Limiting Toxicity (DLT) (DLT criteria defined separately). * Patients without DLT proceed to 2 additional cycles of IBR. * After 3 total cycles: * Efficacy assessment is performed. * Patients achieving minimal response (MR) or better (i.e., MR, PR, VGPR, CR) receive 1 cycle of BR, then cease treatment and enter follow-up. * Patients failing to achieve ≥MR are withdrawn. * Primary Objective: Evaluate safety and identify MTD. Part II (Dose Expansion): * Enroll 15 additional patients at MTD/RP2D. * Objectives: * Further assess safety and efficacy; * Monitor IgM rebound within 2 months after completing therapy (3 cycles I+BR → 1 cycle BR); * Explore correlations between biomarkers and clinical outcomes. Terminology Notes: * I+BR: Ibrutinib + Bendamustine/Rituximab * DLT: Dose-Limiting Toxicity * MTD: Maximum Tolerated Dose * RP2D: Recommended Phase II Dose * Efficacy thresholds: MR (Minimal Response), PR (Partial Response), VGPR (Very Good Partial Response), CR (Complete Response) * Time-limited therapy: Fixed-duration treatment designed to avoid indefinite dosing.

Conditions

• Waldenström Macroglobulinemia (WM)

Interventions

Type	Name	Description
DRUG	Ibrutinib	Oral Bruton's tyrosine kinase (BTK) inhibitor administered at a fixed dose of 420 mg once daily. Capsules must be swallowed whole with water; do not open, break, or chew. If a dose is missed by ≤6 hours, take immediately; if \>6 hours, skip the dose and resume normal schedule the next day. Avoid grapefruit and Seville oranges (moderate CYP3A inhibitors). Treatment duration: 3 cycles (28 days/cycle) or until disease progression/unacceptable toxicity. Dose reduction is mandated for specific toxicities: 420 mg → 280 mg → 140 mg → discontinuation (per protocol-specified criteria). Use with caution in hepatic impairment (Child-Pugh A: reduce to 80 mg/day; Child-Pugh B/C: contraindicated).
DRUG	Bendamustine	Intravenous alkylating agent dosed via a 3+3 dose de-escalation design (70 mg/m² → 60 mg/m² → 50 mg/m²). Infused over 60-120 minutes on Days 1-2 of each 28-day cycle for 3 cycles. Starting dose: 70 mg/m² (Dose Level 1); dose reduction triggered by Dose-Limiting Toxicity (DLT) events per protocol. In the dose-expansion phase, all subjects receive the MTD/RP2D established in Part 1. Concomitant live vaccines are prohibited. Dose delays (≤4 weeks) and reductions are required for Grade ≥3 hematologic/non-hematologic toxicities.
DRUG	Rituximab	Intravenous anti-CD20 monoclonal antibody administered at a fixed dose of 375 mg/m² on Day 0 of each 28-day cycle for 3 cycles. Initial infusion starts at 50 mg/hour; if tolerated, increase by 50 mg/hour every 30 minutes (maximum: 400 mg/hour). Subsequent infusions start at 100 mg/hour with the same escalation. Premedication with acetaminophen and an antihistamine is required prior to each infusion. Permanently discontinue for Grade 4 infusion-related reactions or severe/life-threatening toxicity.

Timeline

• Start date: 2025-09-01
• Primary completion: 2028-09-01
• Completion: 2028-09-01
• First posted: 2025-09-11
• Last updated: 2025-09-11