Mantle Cell Lymphoma in 2026: Auto-Transplant's Role Is fading, BTKi Combinations Are Frontline, and Brexu-cel Has Five-Year Data in RR-MCL

Mantle Cell Lymphoma in 2026: Auto-Transplant's Role Is fading, BTKi Combinations Are Frontline, and Brexu-cel Has Five-Year Data in RR-MCL

Mantle cell lymphoma treatment is being fundamentally reimagined. Autologous stem cell transplant is no longer the universal standard in the frontline setting, chemo-free BTK inhibitor combinations are producing deep remissions across risk groups, and brexucabtagene autoleucel now has five-year data showing a functional cure fraction. Dr. Preetesh Jain reviews the evidence and the MRD-guided strategies defining the next chapter in MCL management.

Introduction: A Disease Being Reimagined

Mantle cell lymphoma is biologically diverse, clinically unpredictable, and historically difficult to treat with sustained efficacy. The standard approach for decades (intensive chemoimmunotherapy followed by autologous stem cell transplant) produced meaningful remissions but not cures for most patients, and the toxicity burden of that approach was substantial.

In 2026, the field is in a period of transformation. Autologous transplant is no longer required for most patients in the first line, and can be potentially replaced by chemo-free BTK inhibitor combinations that match or exceed chemotherapy outcomes with far less toxicity. CAR-T cell therapy has five-year data showing approximately thirty percent of patients alive in ongoing remission. Bispecific antibodies (e.g. Glofitamab) are showing activity even after failure of anti-CD19-CAR-T (Tecartus). And the development of new BCL2 inhibitors, sonrotoclax, BTK degraders, and MRD-guided de-escalation strategies are reshaping how we think about long-term disease management for MCL patients.

Understanding the Disease: Heterogeneity That Matters

Mantle cell lymphoma encompasses a spectrum from an uncommon indolent smoldering disease (which may not need treatment for years) to highly aggressive blastoid or transformed variants that require urgent intervention. Key prognostic factors in current practice include:

• Histopathology (classic vs blastoid vs pleomorphic)
• TP53 and high risk somatic mutation status
• Ki-67 proliferation index (≥50% associated with markedly worse outcomes)
• IGHV mutation status

Genomic complexity, including chromothripsis, a form of massive chromosomal rearrangement now recognized as a major pathogenic mechanism driving genetic instability and resistance

The concept of "triple-resistant mantle cell lymphoma," disease that has progressed through all covalent BTK inhibitors, BCL2 inhibitors, and CAR-T, is emerging as a clinical challenge, and understanding which patients are at highest risk for this trajectory is critical for planning treatment sequences.

A practical risk stratification framework distinguishes:

• Smoldering MCL (observation appropriate)
• Low/intermediate risk, ≤65 years vs >65 years and high risk variants
• TP53-mutated MCL variants (requires distinct treatment consideration)
• Post-covalent BTK, post-venetoclax, and triple-resistant disease

Frontline Treatment: The End of Transplant as a Universal Standard

Evidence That Changed Practice

Three bodies of evidence have largely retired autologous transplant as a universal standard in MCL for newly diagnosed patients:

The TRIANGLE trial (five-year follow-up): A German randomized phase 3 study compared three arms: standard chemotherapy-ASCT (arm A), chemotherapy-ASCT plus ibrutinib (arm A+I), and chemotherapy plus ibrutinib without ASCT (arm I). The five-year follow-up showed a significant overall survival benefit for ibrutinib-containing arms (A+I and I) versus standard chemotherapy-ASCT, confirming that the addition of ibrutinib to frontline chemoimmunotherapy improves outcomes. Importantly, the arms with and without ASCT (A+I vs I) had comparable outcomes in the overall population, though a hypothesis-generating subgroup analysis suggested high-risk patients might still benefit from ASCT. This was the first demonstration that ibrutinib with chemoimmunotherapy improves OS in a large randomized clinical trial in the frontline MCL setting.

EA4181 trial: Combined acalabrutinib with various induction regimens found MRD negativity itself to be a strong predictor of outcomes, with MRD-negative patients not deriving meaningful additional benefit from proceeding to ASCT.

Real-world data from Dr. Martin's group: Confirmed that ASCT does not improve outcomes in MCL patients in the modern era (likely due to the availability of BTK inhibitors).

The practical implication: transplant is no longer routinely indicated for almost all the newly diagnosed MCL patients. High-risk features (TP53 mutation, blastoid histology, high Ki-67, complex genetics) may still warrant ASCT consideration in selected fit patients, but this should be individualized rather than reflexive.

Chemo-Free BTK-Based Approaches: The New Frontline Paradigm

Ibrutinib Plus Rituximab (Jain P et al JCO 2022 at MD Anderson)

The foundational study establishing chemo-free BTK-based therapy in MCL enrolled patients aged ≥65 without blastoid histology or TP53 mutation (low-risk). Ibrutinib plus rituximab induction and IR maintenance then only single agent ibrutinib until progression: ninety-six percent overall response rate and seventy-one percent complete response rate at median forty-two months follow-up. Most patients discontinued ibrutinib due to toxicity during the original study period, though cardiac screening and monitoring have improved substantially since.

SHINE: Ibrutinib Plus Bend-R

SHINE compared ibrutinib plus bendamustine-rituximab versus BR alone in older patients. There was a significant PFS benefit with ibrutinib, but an increased risk of death in the ibrutinib arm, one of the factors that contributed to ibrutinib's withdrawal from the MCL market and raised concerns about ibrutinib-chemotherapy combinations in older patients.

Multiple triplet combinations, including acalabrutinib-venetoclax-rituximab (AVR), zanubrutinib-venetoclax-obinutuzumab (ZVO), and others, are now demonstrating very high MRD negativity rates and excellent two-year PFS and OS outcomes, even in high-risk subsets:

ZVO (zanubrutinib-venetoclax-obinutuzumab): In a TP53-mutated cohort of twenty-five newly diagnosed patients (historically a population with poor outcomes), the best overall response rate was ninety-six percent, two-year PFS seventy-two percent, two-year OS seventy-six percent. For a population where the German multicenter data showed poor outcomes with chemotherapy, this represents meaningful progress.

MAVO study (acalabrutinib-venetoclax-obinutuzumab): High response rates and MRD negativity across risk groups at two years.

Acalabrutinib-rituximab (AR) followed by brexu-cel (anti-CD19 CART) in newly diagnosed high risk MCL patients (Jain P et al ASH 2025): A frontline study using acalabrutinib-rituximab induction followed by brexucabtagene autoleucel (brexu-cel) consolidation in newly diagnosed high-risk MCL, serial MRD and ctDNA assessment. This study is based on the principle that achieving the deepest possible MRD negativity early, in patients at highest relapse risk, may prevent the clonal evolution that drives triple-resistant disease.

Relapsed and Refractory MCL: BTK Resistance and Beyond

Non-Covalent BTK Inhibitors

Pirtobrutinib, the non-covalent BTK inhibitor approved for CLL, is also approved in MCL, including in patients who have failed covalent BTK inhibitors, and is being studied more broadly in frontline combination settings.

Sonrotoclax: A New BCL2/BCL-xL Inhibitor

The most recent approval in MCL is sonrotoclax, a novel BCL2 antagonist with BCL-xL selectivity that distinguishes it from venetoclax. Its BCL-xL selectivity may address venetoclax-resistance mechanisms, and it is also active against the G101V BCL2 mutation (although this is less common in MCL than in CLL). Favorable toxicity profile versus venetoclax, including less neutropenia. Now FDA-approved for MCL.

CAR-T: Five-Year Data and What They Mean

Brexucabtagene autoleucel (brexu-cel, KTE-X19) was the first anti-CD19-CAR-T approved for MCL based on ZUMA-2. Five-year follow-up of cohort one shows approximately thirty percent of patients still alive in ongoing remission, a potential functional cure fraction in a population with historically dismal outcomes. In the high-risk BTKi naïve relapsed MCL cohort (cohort three), results were similarly highly promising with brexu-cel.

Lisocabtagene maraleucel (liso-cel) has shown a much favorable toxicity profile in relapsed MCL cohort with good responses. This anti-CD19-CART is also FDA approved. Retrospective data from the SCHOLAR study showed brexu-cel superior to standard salvage regimens in relapsed MCL.

Zemtocel, a newer CAR-T with improved safety profile and better expansion characteristics, showed promising results in a small cohort including some MCL patients. The ATL-01 cohort of freshly memory-enriched CAR-T showed very deep MRD negativity with short end-to-end manufacturing time.

Post-CAR-T options: Mosunetuzumab plus polatuzumab was studied in forty-two patients with relapsed MCL including approximately thirty percent with prior CAR-T; approximately thirty percent response rate persisting post-CAR-T, suggesting bi-specifics may retain activity after CART therapy failure.

Where the Field Is Going: MRD Eradication as the Target

The unifying theme in frontline MCL development is MRD-guided de-escalation: achieve the deepest possible and sustained MRD negativity with the least toxic frontline regimen, then use serial MRD measurements to determine which group of patients we can de-escalate therapy versus those who needs escalation or consolidation.

The WINDOW-4 study: BTKi-rituximab induction with serial MRD-guided decision-making, followed by glofitamab consolidation in newly diagnosed high-risk MCL patients: a completely chemotherapy-free precision-guided approach for newly diagnosed high-risk MCL. NCT07257055.

MRD-based de-escalation trials: Multiple studies are now using sustained MRD negativity as the criterion for therapy discontinuation, and MRD positivity as the criterion for continuation or intensification. This approach has not yet reached standard practice, but the trials are enrolling and the data will arrive in the next several years.

For Patients

If you have been diagnosed with mantle cell lymphoma: this is a disease where treatment decisions are highly individualized based on your age, your other health conditions, and specific features of the lymphoma itself, particularly whether it has certain high-risk genetic changes.

For many patients who need treatment, the current approach no longer necessarily includes intensive chemotherapy followed by stem cell transplant. Newer regimens combining oral pills such as targeted agents BTK inhibitors combined with other agents can produce high response rates with much lower toxicity, and many patients can achieve deep remissions that may allow therapy to be stopped or de-escalated over time. If you have relapsed after prior treatment, including BTK inhibitors or venetoclax, ask your oncologist about newer options including clinical trials, non-covalent BTK inhibitors, a newer BCL2 inhibitor called sonrotoclax, and discuss CAR-T cell therapy. If you are newly diagnosed, ask specifically whether a clinical trial of a chemotherapy-free or MRD-guided approach is available.

Key Takeaways

• TRIANGLE (five-year follow-up): ibrutinib-containing frontline regimens improved OS vs standard chemoimmunotherapy-ASCT; the ibrutinib arm without ASCT was comparable to the ASCT arm; transplant is no longer universally required.
• Chemo-free BTK combinations (ibrutinib-R, ZVO, MAVO, acalabrutinib-venetoclax-R): high MRD negativity rates and good two-year outcomes across risk groups; TP53-mutated patients achieving 96% ORR, 72% two-year PFS with ZPO.
• Sonrotoclax: new BCL2/BCL-xL inhibitor FDA-approved in MCL; BCL-xL selectivity and activity against G101V BCL2 mutation distinguish it from venetoclax.
• Brexu-cel five-year follow-up (ZUMA-2 cohort 1): approximately thirty percent in ongoing remission; functional cure in a subset of multiply relapsed MCL patients.
• Post-CAR-T relapses-bispecifics (mosunetuzumab-pola): approximately thirty percent response rate, including patients with prior CAR-T; bi-specifics retain activity after CART therapy failure.
• MRD-guided de-escalation and frontline glofitamab consolidation (Window-4) represent the next generation of precision-driven MCL management.
• Triple-resistant MCL (failed all BTK classes, venetoclax, CAR-T) is an emerging challenge; next-generation cellular therapies and BTK degraders are the current focus.

About the Author

Preetesh Jain, MD, DM, PhD is a hematology-oncology clinical investigator and recently joined as an Associate Professor in the Department of Hematology Oncology at Mays Cancer Center, UT Health San Antonio. His research focuses on chemotherapy-sparing targeted and MRD-guided treatment strategies for mantle cell lymphoma, with plans to develop an active program in investigating next generation clinical trials and cellular therapies for MCL patients.

References

1. Dreyling M, Doorduijn J, Giné E, et al. Addition of autologous stem-cell transplantation to an ibrutinib-containing first-line treatment in patients aged 18-65 years with mantle cell lymphoma (TRIANGLE): 4·5-year follow-up of a three-arm, randomised, open-label, phase 3 superiority trial of the European MCL Network. Lancet. 2026;407(10542):1953-1967. doi:10.1016/S0140-6736(26)00362-4.
2. Jain P, Zhao S, Lee HJ, et al. Ibrutinib With Rituximab in First-Line Treatment of Older Patients With Mantle Cell Lymphoma. J Clin Oncol. 2022;40(2):202-212. doi:10.1200/JCO.21.01797
3. Wang ML, Jurczak W, Jerkeman M, et al. Ibrutinib plus Bendamustine and Rituximab in Untreated Mantle-Cell Lymphoma. N Engl J Med. 2022;386(26):2482-2494. doi:10.1056/NEJMoa2201817.
4. Kumar A, Soumerai J, Abramson JS, et al. Zanubrutinib, obinutuzumab, and venetoclax for first-line treatment of mantle cell lymphoma with a TP53 mutation. Blood. 2025;145(5):497-507. doi:10.1182/blood.2024025563.
5. Kim A, et al. Phase I/II study of acalabrutinib, venetoclax, and obinutuzumab in patients with relapsed/refractory and previously untreated Mantle Cell Lymphoma (MAVO). Abstract presented at: 67th American Society of Hematology Annual Meeting and Exposition; December 6-9, 2025; Orlando, FL.
6. Muñoz J, Locke FL, Reagan PM, et al. Five-year follow-up of patients with relapsed/refractory mantle cell lymphoma treated with anti-CD19 CAR T-cell therapy in ZUMA-2, Cohorts 1 and 2. J Hematol Oncol. Published online April 27, 2026. doi:10.1186/s13045-026-01797-4.
7. van Meerten T, Kersten MJ, Iacoboni G, et al. Brexucabtagene autoleucel for BTKi-naive relapsed/refractory mantle cell lymphoma: primary analysis of ZUMA-2 cohort 3. Blood. 2026;147(12):1302-1314. doi:10.1182/blood.2025029734.
8. Budde LE, Zhang H, Kim WS, et al. Mosunetuzumab plus polatuzumab vedotin in transplant-ineligible refractory/relapsed large B-cell lymphoma: primary results of the phase III SUNMO trial. J Clin Oncol. 2025;43(36):3799-3811.
9. Jain P. "Updates in Mantle Cell Lymphoma." Presented at the 2026 Best of Hematology, Austin, TX, May 2026.