Allogeneic stem cell transplantation (alloSCT) exhibits a sustained graft-vs-lymphoma effect in younger patients with peripheral T-cell lymphoma (PTCL), according to a 7-year follow-up of the phase III AATT trial. The study, published in the Journal of Clinical Oncology, compared alloSCT to autologous stem cell transplantation (autoSCT) in patients aged 18-60. While initial analysis showed similar event-free and overall survival outcomes between the two approaches, longer-term data reveal key differences in relapse rates and the efficacy of salvage alloSCT.
The AATT trial randomized 103 patients from France and Germany to either autoSCT (n = 54) or alloSCT (n = 49) as consolidation therapy. The 7-year results indicated event-free survival rates of 38% (95% CI = 25%-52%) in the alloSCT group and 34% (95% CI = 22%-47%) in the autoSCT group. Overall survival rates were 55% (95% CI = 41%-69%) and 61% (95% CI = 47%-74%) for alloSCT and autoSCT, respectively. These differences were not statistically significant.
Outcomes in Transplanted Patients
However, when considering only the patients who actually underwent transplantation (26 in the alloSCT group and 41 in the autoSCT group), notable differences emerged. The 7-year event-free survival rates were 61% for alloSCT and 50% for autoSCT, while overall survival rates were 61% and 72%, respectively; again, these differences were not statistically significant. Critically, the cumulative relapse/disease progression rate was significantly lower in the alloSCT group (8%) compared to the autoSCT group (55%). The nonrelapse mortality rate was 31% in the alloSCT group and 3% in the autoSCT group.
Salvage AlloSCT
Fifteen patients with early disease progression and 11 with disease progression or relapse after autoSCT received salvage alloSCT. The overall survival rate at 7 years after salvage alloSCT was 61%, with a nonrelapse mortality rate of 23%.
Clinical Implications
The study authors, led by Norbert Schmitz, MD, of University Hospital Muenster, Germany, concluded that the long-term follow-up data support the strong graft-vs-lymphoma effect of alloSCT, irrespective of the timing of transplantation. They also noted that survival was poor for patients unable to undergo transplantation. Based on these findings, alloSCT is recommended as the treatment of choice for younger, transplant-eligible patients with relapsed/refractory PTCL, but not as part of first-line consolidation.
