Allogeneic Hematopoietic Cell Transplantation for Relapsed or Refractory Mantle Cell Lymphoma: Real-World Outcomes,...

Allogeneic hematopoietic cell transplantation (alloHCT) remains a curative option for relapsed or refractory (r/r) mantle cell lymphoma (MCL), although its role has shifted in the era of Bruton tyrosine kinase inhibition (BTKi) and chimeric antigen receptor T-cell (CAR-T) therapy. Real-world evidence on long-term outcomes and salvage strategies after relapse is limited.

We performed a retrospective analysis of 29 patients with r/r MCL who underwent alloHCT between 2001 and 2017 using either higher-intensity or reduced-intensity conditioning. Outcomes assessed included overall survival (OS), progression-free survival (PFS), relapse incidence, and non-relapse mortality (NRM), focusing on relapse timing and management. Conditioning regimens were compared exploratorily.

With a median follow-up of 143 months (95% CI: 104-NR), 3-year OS and PFS were 41% and 34%, respectively. Relapse occurred in 38% of patients, including over one quarter with late (> 12-month), predominantly localized relapse. Salvage radiotherapy, alone or combined with BTKi, achieved durable disease control in about two-thirds of patients. Differences between higher-intensity and reduced-intensity conditioning were observed but remained exploratory and not statistically conclusive.

In this real-world cohort, alloHCT provided sustained disease control for a subset of r/r MCL patients, including late, localized relapse amenable to salvage therapy. As alloHCT is now performed less frequently, such datasets are critical for decision-making in patients after CAR-T ineligibility or failure, especially where CAR-T access is limited. These findings support a continued, selective role for alloHCT in the modern treatment landscape and emphasize the need for real-world evidence to guide patient selection and sequencing in the CAR-T era.

The authors have confirmed clinical trial registration is not needed for this submission.