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1520 Allogeneic Hematopoietic Cell Transplantation (allo-HCT) in T-Cell Prolymphocytic Leukemia (T-PLL): An Analysis from the CIBMTR

Program: Oral and Poster Abstracts
Session: 732. Clinical Allogeneic Transplantation: Results: Poster I
Hematology Disease Topics & Pathways:
Diseases, Lymphoid Malignancies
Saturday, December 5, 2020, 7:00 AM-3:30 PM

Hemant S. Murthy, MD1, Kwang Woo Ahn, PhD2,3*, Noel Estrada-Merly, MS4*, Lohith Gowda, MD5, Bhagirathbhai Dholaria, MBBS6, Susan Bal, MD, MBBS7, Hassan B. Alkhateeb, MD8*, Deepa Jagadeesh, MD, MPH9, Betul Oran, MD, MS10, Ryotaro Nakamura, M.D.11, Bart L. Scott, MD12, Craig S. Sauter, MD13, Francine M. Foss, MD14, Mohamed A kharfan-Dabaja, MD, MBA15 and Wael Saber, MD, MS16

1Division of Hematology-Oncology and Blood and Marrow Transplantation Program, Mayo Clinic, Jacksonville, FL
2Division of Biostatistics, Institute for Health and Equity, Medical College of Wisconsin, Milwaukee, WI
3Department of Medicine, CIBMTR (Center for International Blood and Marrow Transplant Research) Medical College of Wisconsin, Milwaukee, WI
4CIBMTR (Center for International Blood and Marrow Transplant Research) Medical College of Wisconsin, Milwaukee, WI
5Hematology, Yale University School of Medicine, New Haven, CT
6Department of Medicine, Division of Hematology and Oncology, Vanderbilt University Medical center, Nashville, TN
7O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL
8Division of Hematology, Mayo Clinic, Rochester, MN
9Taussig Cancer Institute, Department of Hematology and Medical Oncology, Cleveland Clinic, Solon, OH
10Stem Cell Transplantation and Cellular Therapy, The University of Texas, MD Anderson Cancer Center, Houston, TX
11Department of Hematology and Hematopoietic Cell Transplantation, City of Hope, Duarte, CA
12Fred Hutchinson Cancer Center, Seattle, WA
13Memorial Sloan Kettering Cancer Center, New York, NY
14Hematology, Yale Cancer Center, New Haven, CT
15Division of Hematology and Medical Oncology, Mayo Clinic, Jacksonville, FL
16CIBMTR (Center for International Blood and Marrow Transplant Research), Department of Medicine, Medical College of Wisconsin, Milwaukee, WI


T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive malignancy with limited treatment options, frequent relapse, and poor long-term survival. Allogeneic hematopoietic cell transplantation (allo-HCT) is reported to be effective in T-PLL yielding durable remissions and improved survival. Rates of survival and non-relapse mortality vary; data is scant and limited to small retrospective series. Whether regimen intensity – a modifiable factor- is associated with outcomes is unknown. Here, we report an analysis of patients with T-PLL undergoing allo-HCT in 87 centers using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR).


A retrospective multicenter study was conducted utilizing the CIBMTR dataset, which captures all consecutive patients transplanted in participating centers. The study population included patients aged 18 or older with T-PLL who underwent allo-HCT between 2008 and 2018. All donor types, graft sources, and conditioning intensities are summarized (Table 1). Cox regression analysis was used to assess overall mortality, treatment-related mortality (TRM), relapse or progression, disease-free survival (DFS) and acute and chronic graft-versus-host disease (GVHD). Due to the strong correlation between regimen intensity and patients’ age, a combined variable was constructed, and in all models, interactions between age/regimen and significant covariates were examined.


A total of 266 pts were identified and included in this analysis (Table 1). Median follow up of survivors was 49 months (range 3-117); the completeness of survival data out to four years was 95%. In univariate analysis, the 4-year overall survival (OS) rate was 30% (95% confidence interval [CI]: 23.8-36.5%). The 4-year DFS, relapse, TRM rates were 25.72% (95%CI: 20-32%), 41.9% (95%CI: 35.5–48.4%), and 32.4% (95%CI: 26.4-38.6%), respectively. Cumulative incidences of grade 2-4 acute GVHD at day +180 and chronic GVHD at 1-year were 22.5%% (95%CI: 16.8- 28.9%) and 38.3% (95%CI: 32.9–44.9%), respectively.

Multivariate analyses was performed using age (Age >60 vs Age ≤60) and conditioning intensity (myeloablative [MAC] vs. reduced intensity/non-myeloablative [RIC/NMA]) as main effect (Table 2). Poor performance status was associated with inferior TRM, DFS and OS. Compared to MAC/Age ≤ 60, RIC/NMA/Age≤ 60 correlated significantly with less TRM (hazard ratio [HR] 0.28, 95% CI 0.14–0.55, p= 0.0022, superior DFS [HR 0.53, 95% CI 0.35–0.81, p= 0.0029; (Figure 3) and OS HR 0.49, 95% CI 0.32–0.75, p= 0.0009; (Figure 2). Similar trend was observed for RIC/NMA/ Age> 60 for all 3 outcomes but did not reach statistical significance.

Remission status at time of allo-HCT (stable disease or progression vs. complete remission) correlated with relapse (hazard ratio [HR] of relapse=2.13, 95%CI 1.23-3.71, p=0.0072), however degree of response (partial response vs. complete remission did not significantly correlate with relapse (HR of relapse=1.41, 95%CI 0.91-2.17, p=0.1257). In vivo T cell depletion with ATG (N=47) or alemtuzumab (N=2) was associated with worse TRM [HR 1.82, 95% CI 1.08–3.08, p= 0.0255] and inferior DFS [HR of death or progression=HR 1.50, 95% CI 1.05–2.15, p= 0.0276]. The most common cause of death was disease relapse (52%) followed by infection (15%) and GVHD (13%).


This CIBMTR study, with the largest cohort of allo-HCT in T-PLL to date, demonstrates allo-HCT is effective in providing durable remissions. MAC and poor performance status were predictive of inferior TRM and OS. Disease relapse was most common cause of death, and pre-allo-HCT remission inversely correlated with relapse rate. The data suggest that reduced intensity conditioning and avoidance of post-transplant ATG/alemtuzumab may be beneficial. Novel strategies are needed both pre and post-allo-HCT to further improve outcomes.

Disclosures: Dholaria: J&J: Research Funding; bms: Research Funding; Takeda: Research Funding; Poseida: Research Funding; Angiocrine: Research Funding. Jagadeesh: Verastem: Membership on an entity's Board of Directors or advisory committees; Debiopharm Group: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; MEI Pharma: Research Funding; Regeneron: Research Funding. Oran: Celgene: Consultancy; ASTEX: Research Funding; Arog Pharmaceuticals: Research Funding. Nakamura: Viracor: Consultancy; Celgene: Other: Support on seminar; Magenta Therapeutics: Other: Advisory board meeting; NapaJen Pharma: Consultancy; Alexion: Other: Support on a meeting presentation; Merck: Other: advisory board meeting; Kadmon Corporation: Other: Advisory board meeting; Kyowa-Kirin: Other: Support on a meeting presentation. Sauter: Spectrum Pharamaceuticals: Consultancy; Sanofi-Genzyme: Consultancy, Research Funding; Gamida Cell: Consultancy; Novartis: Consultancy; Genmab: Consultancy; Precision Biosciences: Consultancy, Research Funding; Kite - a Gilead Company: Consultancy; Celgene: Consultancy, Research Funding; GSK: Consultancy; Bristol-Myers Squibb: Research Funding; Juno Therapeutics: Consultancy, Research Funding. kharfan-Dabaja: Daiichi Sankyo: Consultancy; Pharmacyclics: Consultancy.

*signifies non-member of ASH