Autologous (auto) Versus Allogeneic (allo) Hematopoietic Cell Transplantation (HCT) for T-NHL: A CIBMTR Analysis

T-cell lymphomas (T-NHL) are aggressive, heterogeneous malignancies, marked by chemoresistance with fewer than one-third of patients achieving disease control with non-transplant therapies. There are no large comparative studies of autoHCT and alloHCT in T-NHL. We analyzed post-transplant outcomes of 241 recipients (≤ 60 yrs) of autoHCT (n=115) and alloHCT (n=126, 76 matched siblings) for T-NHL between 1996–2006 reported to the CIBMTR. Median age was 43 yrs for autoHCT and 38 yrs for alloHCT. In the alloHCT cohort: 59% received myeloablative conditioning, 60% had matched sibling donors. Histology was heterogeneous (Table 1).

Median time to transplant after diagnosis was similar in both groups (10m vs. 11m). AutoHCT, compared to alloHCT, was used more in ALCL (53% vs. 40%, p=0.04) and in those with less advanced and more sensitive disease: first complete remission (CR1) (35% vs. 14%, p=0.001), chemosensitive disease (86% vs. 60%, p<0.0001), and ≤ 2 lines prior therapy (65% vs. 44%, p<0.001). Median follow-up was 71m for autoHCT and 49m for alloHCT. Treatment related mortality (TRM) at 100 days in the autoHCT and alloHCT cohorts was 2% and 17%, respectively. For those beyond CR1, overall survival (OS) at 1 yr was 62% vs. 52% and at 3-yrs 53% vs. 41% for the autoHCT and alloHCT cohorts, respectively (Table 2). Relapsing T-NHL was the cause of death in 73% of autoHCT and 44% of alloHCT pts.

In multivariate analysis, alloHCT and more pretransplant chemotherapy regimens were associated with a higher risk of TRM. Relapse risk was higher with chemotherapy resistant disease and those not in CR. PFS and OS were similar after autoHCT or alloHCT with a greater number of prior chemotherapy regimens and chemotherapy resistance impacting survival outcomes adversely. Among 101 peripheral T cell lymphoma (PTCL) pts, the risk of relapse was significantly lower with alloHCT (RR 0.5, 95% CI 0.26–0.97) but countered by increased TRM for alloHCT (RR 3.03, 95% CI 1.02 –8.96). PFS and OS after autoHCT or alloHCT for PTCL were similar and adversely affected by pretransplant chemotherapy resistance. Among alloHCT recipients, there were no differences in outcomes based on donor source, conditioning regimen type or intensity.

In summary, pts undergoing autoHCT for T cell NHL appear to be selected for less advanced disease and greater chemosensitivity, making direct outcome comparisons with alloHCT difficult. AlloHCT is an effective strategy for high risk patients, albeit with significant TRM. Higher numbers of chemotherapy regimens prior to transplant adversely impacted both TRM and survival, suggesting that HCT should be considered earlier in the disease course.

No relevant conflicts of interest to declare.