EBMT Registry: HCT Outcomes Improved in Hodgkin Lymphoma

Key Takeaways

• In adults with relapsed or refractory classical Hodgkin lymphoma in the EBMT registry, post-transplant outcomes improved over later calendar eras after both auto-HCT and allo-HCT.
• Auto-HCT was associated with higher 2-year PFS and OS in 2019-22 than in 2010-14.
• Allo-HCT also showed better 2-year PFS and OS in later study years.
• Remission status at transplantation remained associated with PFS, with worse outcomes outside complete remission in both transplant settings.

Relapsed or refractory classical Hodgkin lymphoma still brings clinicians back to transplant timing and expected benefit, particularly as newer therapies may have shifted what outcomes look like after haematopoietic cell transplantation (HCT). Autologous HCT (auto-HCT) remains the standard transplant setting for chemosensitive relapse, while allogeneic HCT (allo-HCT) remains part of the pathway after unsuccessful auto-HCT. Investigators examined how post-transplant outcomes changed over recent calendar eras and whether disease status at transplantation continued to shape prognosis.

In a retrospective, registry-based cohort study from the European Society for Blood and Marrow Transplantation (EBMT), investigators included adults aged 18 years or older with relapsed or refractory classical Hodgkin lymphoma who underwent first auto-HCT or first allo-HCT between Jan 1, 2010, and Dec 31, 2022, according to the EBMT registry cohort study in The Lancet Haematology. Of 22,047 first transplants identified, 1,324 were excluded for missing follow-up and 1,225 for nodular lymphocyte predominant Hodgkin lymphoma, leaving 19,498 patients for analysis, including 15,648 auto-HCT recipients and 3,850 allo-HCT recipients. The registry included more than 600 transplantation centres across 53 countries, underscoring that these were international rather than U.S.-specific data; median follow-up was 2.4 years for auto-HCT and 3.9 years for allo-HCT, and primary endpoints were progression-free survival (PFS) and overall survival (OS) at 2 and 5 years after HCT.

Across calendar eras, 2-year outcomes improved in both transplant settings. After auto-HCT, PFS rose from 63% to 73% and OS from 85% to 93% between 2010-14 and 2019-22. After allo-HCT, PFS rose from 44% to 62% and OS from 66% to 72% over the same interval.

Disease status at transplantation remained a consistent prognostic marker in the remission-status associations with progression-free survival after HCT. Compared with complete remission at transplantation, partial response and stable or progressive disease were associated with worse PFS after auto-HCT, with hazard ratios of 1.92 and 2.45, respectively; the same pattern appeared after allo-HCT, with hazard ratios of 1.58 and 2.28.

Because this was a retrospective registry cohort, the survival gains seen across calendar eras cannot be attributed to any single treatment or supportive-care change; in the study report, improvements were described as being driven mainly by reduced relapse incidence, with non-relapse mortality changing little overall, and outcomes were also associated with factors such as age, performance status, and, in allo-HCT, conditioning intensity, donor type, checkpoint inhibitor exposure, and post-transplant cyclophosphamide. Even so, the international EBMT experience offers contemporary benchmark data for post-transplant outcomes in relapsed or refractory classical Hodgkin lymphoma. The authors concluded that improving outcomes after both auto-HCT and allo-HCT could help inform prospective trials or additional studies, while remission status at transplantation remained an important prognostic factor.

Clinician Questions

Which patients were included in the EBMT transplant cohort for relapsed or refractory classical Hodgkin lymphoma?

The cohort included adults aged 18 years or older with relapsed or refractory classical Hodgkin lymphoma who underwent first auto-HCT or first allo-HCT between 2010 and 2022 in the EBMT registry. Investigators identified 22,047 first transplants and retained 19,498 after excluding patients with missing follow-up and those with nodular lymphocyte predominant Hodgkin lymphoma.

How did the EBMT analysis define the transplant settings being compared?

The study analyzed first autologous and first allogeneic HCT separately. Patients receiving allo-HCT for relapse after auto-HCT were eligible, tandem transplantations were excluded, and allogeneic grafts could come from matched related, mismatched related, or unrelated donors.

What do these findings support, and what do they not establish?

The registry data support contemporary benchmarking of 2-year PFS and OS after auto-HCT and allo-HCT and show that remission status at transplantation remained associated with PFS. The findings describe time trends and prognostic associations rather than proving which treatment-era changes caused them.