Background
Phase 3, open-label, randomized controlled trial (SEQUOIA; BGB-3111-304). N=590 treatment-naive CLL/SLL patients. Cohort A (N=479, non-del17p): zanubrutinib vs bendamustine-rituximab (BR), randomized 1:1. Cohort B (N=111, del17p): single-arm zanubrutinib. Zanubrutinib is a next-generation, highly selective covalent BTK inhibitor with sustained full-cycle BTK occupancy. Patients ≥18 years, any CIRS score, symptomatic CLL requiring treatment.
Interventions and follow up
Arm A: Zanubrutinib 160 mg PO twice daily continuously until progression or unacceptable toxicity
Arm B: Bendamustine 90 mg/m² IV days 1–2 + rituximab 375 mg/m² day 1 cycle 1 then 500 mg/m² day 1 cycles 2–6; 6 cycles q28d (BR)
Primary endpoint: Progression-free survival (PFS) by independent review committee (Cohort A)
Median follow-up: 26.2 months (primary); 61.2 months (5-year JCO 2024 update)
Arm B: Bendamustine 90 mg/m² IV days 1–2 + rituximab 375 mg/m² day 1 cycle 1 then 500 mg/m² day 1 cycles 2–6; 6 cycles q28d (BR)
Primary endpoint: Progression-free survival (PFS) by independent review committee (Cohort A)
Median follow-up: 26.2 months (primary); 61.2 months (5-year JCO 2024 update)
Results
mPFS (primary): Not reached vs 33.7 months, HR 0.42 (95% CI 0.28–0.63), P<.0001
5-yr update (JCO 2024): mPFS NR vs 44.1 months, HR 0.29 (95% CI 0.21–0.40)
ORR: 94.6% vs 85.3%
CR: 4.6% vs 6.3% (CR rates low at primary due to short follow-up)
60-mo OS: 85.8% vs 85.0% — no significant difference
5-yr update (JCO 2024): mPFS NR vs 44.1 months, HR 0.29 (95% CI 0.21–0.40)
ORR: 94.6% vs 85.3%
CR: 4.6% vs 6.3% (CR rates low at primary due to short follow-up)
60-mo OS: 85.8% vs 85.0% — no significant difference
Adverse events
Cardiovascular: Atrial fibrillation any grade 5.2% (zanubrutinib) vs 2.9% (BR) at primary, 7.1% at 5 years; hypertension grade ≥3 3.3% vs 0.8%; major hemorrhage 2.1% vs 0.8%; no ventricular arrhythmias reported
Hematologic: Grade ≥3 neutropenia 29.4% vs 39.3%
Infections: Grade ≥3 infections 16.2% vs 12.6%
Discontinuation due to AEs: 21% (zanubrutinib) vs 14% (BR) at 5 years
Hematologic: Grade ≥3 neutropenia 29.4% vs 39.3%
Infections: Grade ≥3 infections 16.2% vs 12.6%
Discontinuation due to AEs: 21% (zanubrutinib) vs 14% (BR) at 5 years
Conclusions
Zanubrutinib demonstrated significantly superior PFS over BR in treatment-naive CLL, with a 5-year PFS HR of 0.29 and sustained benefit. The low AFib rate (7.1% at 5 years) reinforces zanubrutinib's improved cardiac safety profile relative to ibrutinib. No OS benefit over BR was observed.
Key Limitations
BR is an infrequently used comparator where FCR (or VenObi) is preferred for fit patients; comparison with ibrutinib (ALPINE) is more clinically relevant for BTKi selection. No OS benefit despite a pronounced PFS advantage, reflecting effective salvage at progression. Long-term continuous BTKi therapy accumulates toxicity and AFib rates rise over time, whereas fixed-duration venetoclax-based regimens permit treatment cessation. Del(17p) Cohort B is non-randomized, limiting interpretation.
Clinical Context
SEQUOIA supported FDA approval of zanubrutinib for treatment-naive CLL (January 2023) and EMA approval. Together with ALPINE (zanubrutinib vs ibrutinib R/R) and SEQUOIA Arm B (del17p), zanubrutinib is a preferred BTKi for CLL across settings, favored over ibrutinib at most centers due to improved cardiac safety. CLL17 subsequently demonstrated fixed-duration VenO and VenI non-inferior to continuous ibrutinib, providing a treatment-cessation alternative. ESMO-MCBS: not assigned.