Standard chemotherapy followed by allogeneic or autologous transplantation: The role of allogeneic transplantation in the AATT study.
Authors: Schmitz Norbert , Altmann Bettina , Friedrichs Birte , Bouabdallah Krimo , Cartron Guillaume , Nickelsen Maike , Wulf Gerald , Leclerc Mathieu , Vilatte Alban , Turlure Pascal , Houot Roch , De Leval Laurence , Gaulard Philippe , Ott German , Damaj Gandhi Laurent , Reimer Peter , Lenz Georg , Trumper Lorenz H. , Ziepert Marita , Tournilhac Olivier ,   for the French (LYSA and SFGM-TC) and German Lymphoma Alliance (GLA)
Published: June 2022

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Background: Prognosis of relapsed and refractory T-cell lymphoma patients (pts) is devastating. Early results of the AATT study (Autologous or Allogeneic Transplantation in T-cell lymphoma, Schmitz et al. ASCO 2019; NCT00984412) showed that standard chemotherapy followed by allogeneic transplantation (alloSCT) compared to autoSCT did not improve outcome of poor-risk patients. We wanted to investigate the long-term clinical course of AATT patients (pts) focusing on pts receiving alloSCT off study. Methods: AATT was a randomized trial comparing alloSCT with autoSCT in younger pts (18-60 yrs) with newly diagnosed PTCL who achieved stable disease or better after 4 courses of CHOEP and 1 course of DHAP. Pts were to receive BEAM/autoSCT or myeloablative conditioning/alloSCT from matched related or unrelated donors for consolidation. Local investigators gave updated detailed reports on all further therapy until last follow up or death in order to report long-term EFS and OS focusing on patients receiving alloSCT off study and after failing autoSCT. Results: 103 pts (median age 50 years) randomized to autoSCT (n = 54) or alloSCT (n = 49) formed the full analysis set (FAS), 67 pts (65%) actually received autoSCT (n = 41) or alloSCT (n = 26) (per protocol set, PPS). Median observation time for EFS (OS) was 80 (84) months in the FAS and PPS population. At 7 years EFS and OS were 36% [95%CI: 27% - 46%] and 58% [48-68] for all 103 pts; EFS and OS for patients randomized to autoSCT vs. alloSCT were 34% [22-47] vs. 38% [25-52] and 61% [47-74] vs. 55% [41-69]. For patients actually transplanted 7-year-EFS and -OS were 50% [34-66] vs. 61% [42-80] and 72% [58-86] vs. 61% [42-80]. None of these survival rates differed significantly. TRM was 0/41 (0%) after autoSCT and 8/26 (31%) after alloSCT. Relapse rates were 15/36 (42%) vs. 1/21 (5%) for patients auto- or allografted. Overall, 26/ 50 pts received alloSCT off study because of early relapse/ progression before transplantation or after failing autoSCT. 7-year-OS for these pts is 62% (43-80). Ten of 15 pts relapsing after autoSCT received alloSCT as next therapy. Eight of these pts remain alive 39 – 94 mos after transplantation 5-year-OS of 24 pts who did not receive alloSCT was 17% (2-32). Conclusions: Seven-year OS-rates for the FAS- and the PPS cohort are remarkably high (58% and 68%) reflecting the high rate of long-term survivors after alloSCT also in pts with early relapse and after autoSCT. Pts not undergoing alloSCT had a dismal outcome. For T-cell lymphoma pts with early progression/ relapse after first-line therapy or failing autoSCT alloSCT offers cure in a significant portion of pts and should therefore be the preferred option for all transplant-eligible pts. Clinical trial information: NCT00984412.