Background
Phase II, single-arm, multicenter study. 68 patients with R/R MZL (all subtypes: nodal, extranodal MALT, splenic) after ≥1 prior anti-CD20-containing therapy. Zanubrutinib is a highly selective covalent BTK inhibitor with >97% BTK occupancy and fewer off-target kinase effects than ibrutinib. MAGNOLIA established zanubrutinib's activity in R/R MZL.
Interventions and follow up
Regimen: Zanubrutinib 160 mg PO twice daily continuously, in R/R marginal zone lymphoma after ≥1 anti-CD20–based therapy
Primary endpoint: Overall response rate (independent review committee)
mFollow up: ~35.1 months (final analysis)
Primary endpoint: Overall response rate (independent review committee)
mFollow up: ~35.1 months (final analysis)
Results
ORR (primary): 68.2% (95% CI 55.6–79.1%)
CR rate: 25.8%
24-month PFS: 70.9%
mDOR: 55.5 months
mPFS: Not reached
CR rate: 25.8%
24-month PFS: 70.9%
mDOR: 55.5 months
mPFS: Not reached
Adverse events
Overall/hematologic: Grade ≥3 AEs 48.5%; grade ≥3 neutropenia 11.8%; treatment discontinuation due to AEs 5.9%
Cardiovascular/bleeding: Atrial fibrillation any grade 2.9% (lower than ibrutinib ~10–16%); major bleeding 0%; hypertension grade ≥3 0% (vs ~7% with ibrutinib)
Cardiovascular/bleeding: Atrial fibrillation any grade 2.9% (lower than ibrutinib ~10–16%); major bleeding 0%; hypertension grade ≥3 0% (vs ~7% with ibrutinib)
Conclusions
Zanubrutinib achieved a 68.2% ORR with durable responses (mDOR 55.5 months) in R/R MZL with markedly fewer cardiovascular toxicities (atrial fibrillation 2.9%, no major bleeding) compared to ibrutinib, supporting its preferred status over ibrutinib in MZL.
Key Limitations
Single-arm Phase II with no randomized comparator and a small sample (n=68), limiting subgroup interpretation across MZL subtypes. Cross-trial comparisons of cardiovascular toxicity with ibrutinib are not head-to-head and may be confounded. As a continuous oral therapy, zanubrutinib requires indefinite treatment with attendant cumulative cost and adherence considerations. mPFS not reached limits long-term durability estimates.
Clinical Context
MAGNOLIA supported FDA accelerated approval of zanubrutinib for R/R MZL after ≥1 anti-CD20-based therapy (September 2021). Its favorable cardiovascular and bleeding profile relative to ibrutinib (which received an earlier MZL approval) makes zanubrutinib a preferred BTK inhibitor in MZL. ESMO recognizes BTK inhibitors as an option in R/R MZL. Choice in R/R MZL also includes rituximab-based chemoimmunotherapy and lenalidomide-rituximab.