Allogeneic Stem Cell Transplantation for Mantle Cell Lymphoma Can Achieve Durable Remission and Myeloablative Conditioning Is Associated with Inferior Survival: An Australasian Bone Marrow Transplant Recipient Registry Study

• Published in: Blood 2020-11, Vol.136 (Supplement 1), p.7-8
• Main Authors: Di Ciaccio, Pietro R, Ritchie, David, Kennedy, Glen A, Milliken, Sam, Purtill, Duncan, Gottlieb, David, Perera, Travis, Yeung, David T, Larsen, Stephen R, Doocey, Richard, Greenwood, Matthew, Durrant, Simon, Watson, Anne-Marie, Butler, Andrew, Khot, Amit, Curley, Cameron, Hamad, Nada
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2020-139057

Introduction Mantle cell lymphoma (MCL) is a mature B lymphoproliferative disorder with a frequently aggressive clinical course. Although the response rates in patients eligible for conventional chemoimmunotherapy are high, relapses are virtually inevitable, with a median overall survival (OS) of three to five years. For some patients allogeneic stem haematopoietic cell transplantation (alloHCT) is a potential therapeutic option. AlloHCT for MCL has been associated with long term overall survival (OS) of around 40%, with high rates of non-relapse mortality (NRM) of 20-40% and relapse rates of 20-30% (Urbano-Ispizua et al., Biol Blood Marrow Transplant 2015;21:1746, Robinson et al., Leukemia 2015;29:464). Whilst there is evidence of a graft-versus-lymphoma effect in MCL, it has not been shown to translate into improved OS. We performed a retrospective national registry study to examine alloHCT practice and outcomes for MCL in Australia and New Zealand in the modern era. Methods Data was collected through the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) for patients receiving an alloHCT for MCL between January 2009 and December 2019. This time range was chosen to capture the era of widespread rituximab use. Survival, relapse and toxicities of alloHCT were investigated, as well as transplant trends over time. Survival was analysed using the Kaplan-Meier method, with comparisons between the transplant periods 2009-2014 and 2015-2019 performed using the log-rank test. Cox proportional hazards regression was performed to determine significant risk factors for transplant outcome. The following risk factors were analysed for impact on outcomes: age, transplant before 2015, previous autologous HCT (autoHCT), remission status at transplant, use of myeloablative conditioning (MAC), haploidentical donor and use of T cell depletion (TCD). Results A total of 86 patients were included in the analysis. The median age was 56 (range 39-71). There was a male predominance with only 12% female patients. At the time of transplant, 51% were in complete remission, 26% had a partial response and 20% had stable or progressive disease (data missing in 3%). Sixty-seven percent had undergone previous autoHCT. The majority of donors were HLA-matched siblings (51%), followed by HLA-matched-unrelated (42%) and haploidentical (7%). Myeloablative conditioning was utilised in 14%, and T-cell depletion (TCD) in 24%. The median times to neutrophil engraftment (>0.5x109/L) a