A chemotherapy-free treatment for newly diagnosed mantle cell lymphoma has moved closer to potential FDA approval after a Phase 3 trial demonstrated a 43% reduction in the risk of disease progression or death compared with standard chemoimmunotherapy.
On November 4, 2026, BeOne Medicines announced that the U.S. Food and Drug Administration (FDA) had accepted and granted Priority Review to its supplemental New Drug Application (sNDA) for zanubrutinib (BRUKINSA) in combination with rituximab for adults with previously untreated mantle cell lymphoma (MCL).
The regulatory decision follows positive results from the Phase 3 MANGROVE trial, which demonstrated a significant improvement in progression-free survival (PFS) with zanubrutinib plus rituximab compared with bendamustine plus rituximab, a widely used first-line chemoimmunotherapy regimen.
If approved, the combination would become the first FDA-approved chemotherapy-free, BTK inhibitor-based regimen specifically indicated for adults with previously untreated MCL.
The development represents an important step in the ongoing shift toward targeted, chemotherapy-sparing treatment strategies for patients with hematologic malignancies.
MANGROVE Trial: Zanubrutinib Reduces Progression Risk by 43%
The FDA submission is supported by results from MANGROVE (BGB-3111-306; NCT04002297), a global, randomized, open-label Phase 3 trial comparing zanubrutinib plus rituximab with bendamustine plus rituximab in patients with previously untreated MCL.
The study enrolled 510 patients across 157 clinical sites worldwide, focusing on a population generally unsuitable for intensive transplant-based treatment.
MANGROVE met its primary endpoint of PFS, as assessed by an independent review committee.
The key findings included:
- 43% reduction in the relative risk of disease progression or death with zanubrutinib plus rituximab.
- Hazard ratio: 0.57 (95% CI, 0.43–0.76).
- Statistical significance: p<0.0001.
- Safety findings consistent with the established profiles of both treatments, with no new safety signals identified.
These findings provide randomized Phase 3 evidence that a chemotherapy-free approach can achieve superior disease control compared with an established chemoimmunotherapy regimen in this setting.
However, the 43% reduction refers specifically to the relative risk of progression or death and should not be interpreted as a 43% reduction in overall mortality.
Overall survival data were immature at the initial analysis, although the company reported a favorable trend with the zanubrutinib combination.
Why a Chemotherapy-Free Approach Matters in Mantle Cell Lymphoma
Mantle cell lymphoma is a relatively rare but frequently aggressive form of B-cell non-Hodgkin lymphoma, accounting for approximately 5–7% of non-Hodgkin lymphoma cases in Western populations.
The disease primarily affects older adults and is characterized by considerable biological heterogeneity. Although some patients experience relatively indolent disease, others develop rapidly progressive lymphoma requiring intensive treatment.
Despite advances in targeted therapies, MCL remains challenging to manage because many patients eventually experience relapse. For older patients and those unable to undergo autologous stem cell transplantation, bendamustine plus rituximab has long been an established first-line treatment option.
However, chemotherapy-based regimens can cause significant treatment-related toxicity, including myelosuppression, infections, immune suppression, and impaired quality of life. As a result, researchers have increasingly investigated whether targeted agents can achieve comparable or superior disease control while reducing exposure to cytotoxic chemotherapy.
Zanubrutinib is a next-generation Bruton tyrosine kinase (BTK) inhibitor designed to block signaling pathways that support malignant B-cell proliferation and survival.
Rituximab is a monoclonal antibody targeting CD20, a protein expressed on the surface of B cells.
By combining these two agents, investigators aim to suppress lymphoma growth through complementary mechanisms without conventional chemotherapy.
How Was Zanubrutinib Combined With Rituximab?
In the MANGROVE trial, patients were randomized to receive either a zanubrutinib-based treatment strategy or standard chemoimmunotherapy.
Patients in the experimental group received zanubrutinib 160 mg orally twice daily, combined with rituximab during the initial treatment period.
Following completion of the rituximab-containing phase, patients continued zanubrutinib monotherapy until disease progression or unacceptable toxicity.
Patients in the control group received six cycles of bendamustine plus rituximab.
An important distinction is that the experimental regimen avoids conventional cytotoxic chemotherapy and prolonged rituximab maintenance. This approach may reduce chemotherapy-associated toxicity and the burden of repeated infusion visits, although patients receiving zanubrutinib would require ongoing oral treatment and monitoring.
Beyond the primary PFS endpoint, MANGROVE evaluates overall survival, overall response rate, duration of response, investigator-assessed PFS, patient-reported outcomes, and safety.
What Does FDA Priority Review Mean for Zanubrutinib?
The FDA’s Priority Review designation is reserved for applications that, if approved, could offer meaningful improvements in the treatment, prevention, or diagnosis of serious conditions. Under this pathway, the FDA generally aims to complete its review within six months, compared with approximately ten months under standard review.
However, Priority Review does not guarantee regulatory approval, and the designation does not lower the scientific standards required to establish safety and efficacy.
BeOne Medicines has also submitted an application for zanubrutinib in MCL to the European Medicines Agency (EMA), while the corresponding application has been accepted for review by China’s National Medical Products Administration (NMPA).
Zanubrutinib is already approved in the United States for several B-cell malignancies, including relapsed or refractory MCL, chronic lymphocytic leukemia/small lymphocytic lymphoma, Waldenström’s macroglobulinemia, and certain relapsed or refractory indolent lymphomas.
The latest application seeks to extend its role into the first-line treatment setting for MCL.
Could Zanubrutinib Change the First-Line Treatment Landscape?
The use of BTK inhibitors in newly diagnosed MCL has already begun to transform treatment strategies.
In January 2025, the FDA approved acalabrutinib in combination with bendamustine and rituximab for adults with previously untreated MCL who were ineligible for autologous hematopoietic stem cell transplantation.
That decision was based on the Phase 3 ECHO trial, which demonstrated improved progression-free survival when a BTK inhibitor was added to standard chemoimmunotherapy.
MANGROVE addresses a different clinical question.
Rather than adding targeted therapy to chemotherapy, can chemotherapy be removed altogether while maintaining or improving treatment efficacy?
The trial’s positive results suggest that this strategy may be feasible for selected patients with previously untreated MCL.
However, the MANGROVE and ECHO trials evaluated different treatment approaches and patient populations, making direct comparisons of their efficacy results inappropriate.
Important unanswered questions include whether the PFS benefit translates into longer overall survival, the long-term tolerability of continuous BTK inhibition, and whether patients with high-risk disease features, such as TP53 alterations or blastoid morphology, derive comparable benefits.
Safety and Long-Term Outcomes Remain Important Questions
According to BeOne Medicines, the safety profile of zanubrutinib plus rituximab was consistent with the established safety profiles of the individual medicines, and no new safety signals were identified.
Nevertheless, zanubrutinib carries clinically important risks, including hemorrhage, infections, cytopenias, cardiac arrhythmias, second primary malignancies, and hepatotoxicity.
Because patients may remain on zanubrutinib for extended periods, longer follow-up will be essential to evaluate treatment-related adverse events, discontinuation rates, and quality-of-life outcomes.
Overall survival is another critical endpoint.
In its June 2026 announcement, BeOne Medicines reported that overall survival data were not yet mature, although a favorable trend was observed in the experimental arm.
Formal overall survival testing is planned as part of the final analysis.
Full MANGROVE Results to Be Presented at ASH 2026
The next major milestone for the zanubrutinib combination will be the presentation of the full Phase 3 MANGROVE results at the 68th American Society of Hematology (ASH) Annual Meeting on December 13, 2026.
The findings are scheduled for presentation during the meeting’s Plenary Scientific Session.The presentation is expected to provide additional details on efficacy and safety, helping clinicians better understand the magnitude and durability of the treatment benefit.
These data will be particularly important for evaluating the role of zanubrutinib in the evolving first-line MCL treatment landscape.
For patients who are older, have significant comorbidities, or are unable to tolerate intensive treatment, the possibility of achieving improved disease control without conventional chemotherapy represents an important therapeutic development.
The FDA’s Priority Review marks a significant regulatory milestone for zanubrutinib and reinforces growing interest in chemotherapy-free treatment strategies for mantle cell lymphoma.
If approved, zanubrutinib plus rituximab could expand first-line treatment options and offer an alternative to conventional chemoimmunotherapy.
The central question now is whether the promising progression-free survival benefit observed in MANGROVE will translate into durable clinical outcomes, acceptable long-term safety, and meaningful improvements in patients’ lives.