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1.
Post-Transplantation Cyclophosphamide-Based Graft-versus-Host Disease Prophylaxis
Bolaños-Meade, J., Hamadani, M., Wu, J., Al Malki, M. M., Martens, M. J., Runaas, L., Elmariah, H., Rezvani, A. R., Gooptu, M., Larkin, K. T., et al
The New England journal of medicine. 2023;388(25):2338-2348
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Editor's Choice
Abstract
BACKGROUND In patients undergoing allogeneic hematopoietic stem-cell transplantation (HSCT), a calcineurin inhibitor plus methotrexate has been a standard prophylaxis against graft-versus-host disease (GVHD). A phase 2 study indicated the potential superiority of a post-transplantation regimen of cyclophosphamide, tacrolimus, and mycophenolate mofetil. METHODS In a phase 3 trial, we randomly assigned adults with hematologic cancers in a 1:1 ratio to receive cyclophosphamide-tacrolimus-mycophenolate mofetil (experimental prophylaxis) or tacrolimus-methotrexate (standard prophylaxis). The patients underwent HSCT from an HLA-matched related donor or a matched or 7/8 mismatched (i.e., mismatched at only one of the HLA-A, HLA-B, HLA-C, and HLA-DRB1 loci) unrelated donor, after reduced-intensity conditioning. The primary end point was GVHD-free, relapse-free survival at 1 year, assessed in a time-to-event analysis, with events defined as grade III or IV acute GVHD, chronic GVHD warranting systemic immunosuppression, disease relapse or progression, and death from any cause. RESULTS In a multivariate Cox regression analysis, GVHD-free, relapse-free survival was significantly more common among the 214 patients in the experimental-prophylaxis group than among the 217 patients in the standard-prophylaxis group (hazard ratio for grade III or IV acute GVHD, chronic GVHD, disease relapse or progression, or death, 0.64; 95% confidence interval [CI], 0.49 to 0.83; P = 0.001). At 1 year, the adjusted GVHD-free, relapse-free survival was 52.7% (95% CI, 45.8 to 59.2) with experimental prophylaxis and 34.9% (95% CI, 28.6 to 41.3) with standard prophylaxis. Patients in the experimental-prophylaxis group appeared to have less severe acute or chronic GVHD and a higher incidence of immunosuppression-free survival at 1 year. Overall and disease-free survival, relapse, transplantation-related death, and engraftment did not differ substantially between the groups. CONCLUSIONS Among patients undergoing allogeneic HLA-matched HSCT with reduced-intensity conditioning, GVHD-free, relapse-free survival at 1 year was significantly more common among those who received cyclophosphamide-tacrolimus-mycophenolate mofetil than among those who received tacrolimus-methotrexate. (Funded by the National Heart, Lung, and Blood Institute and others; BMT CTN 1703 ClinicalTrials.gov number, NCT03959241.).
PICO Summary
Population
Adults with hematologic cancers undergoing HLA-matched related donor or a matched or 7/8 mismatched unrelated donor transplant, enrolled in an RCT in multiple centres in USA (n=431)
Intervention
Cyclophosphamide-tacrolimus-mycophenolate mofetil (experimental prophylaxis, n=214)
Comparison
Tacrolimus-methotrexate (standard prophylaxis (standard prophylaxis, n=217)
Outcome
GVHD-free, relapse-free survival was significantly more common among patients in the experimental-prophylaxis group than among the standard-prophylaxis group (hazard ratio for grade III or IV acute GVHD, chronic GVHD, disease relapse or progression, or death, 0.64; 95% confidence interval [CI], 0.49 to 0.83). At 1 year, the adjusted GVHD-free, relapse-free survival was 52.7% (95% CI, 45.8 to 59.2) with experimental prophylaxis and 34.9% (95% CI, 28.6 to 41.3) with standard prophylaxis. Patients in the experimental-prophylaxis group appeared to have less severe acute or chronic GVHD and a higher incidence of immunosuppression-free survival at 1 year. Overall and disease-free survival, relapse, transplantation-related death, and engraftment did not differ substantially between the groups.
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Haploidentical donor hematopoietic cell transplantation for myelodysplastic/myeloproliferative overlap neoplasms: results from a North American collaboration
Jain, T., Tsai, H. L., Elmariah, H., Vachhani, P., Karantanos, T., Wall, S. A., Gondek, L. P., Bashey, A., Keyzner, A., Tamari, R., et al
Haematologica. 2023
Abstract
Haploidentical donors offer a potentially readily available donor, especially for non-White patients, for hematopoietic cell transplantation (HCT). In this North American collaboration, we retrospectively analyzed outcomes of first HCT using haploidentical donor and posttransplantation cyclophosphamide (PTCy) in MDS/MPN-overlap neoplasms (MDS/MPN). We included 120 consecutive patients who underwent HCT using a haploidentical donor for MDS/MPN across 15 centers. Median age was 62.5 years and 38% were of non-White/Caucasian ethnicity. The median follow-up was 2.4 years. Graft failure was reported in 7/120 (6%) of patients. At 3 years, nonrelapse mortality (NRM) was 25% (95%CI 17-34%), relapse 27% (95%CI 18-36%), grade 3-4 acute graft versus host disease (GVHD) 12% (95%CI 6-18%), chronic GVHD requiring systemic immunosuppression 14% (95%CI 7-20%), progression-free survival (PFS) 48% (95%CI 39-59%), and overall survival (OS) 56% (95%CI 47-67%). On multivariable analysis, NRM was statistically significantly associated with advancing age at HCT (per decade increment, sdHR 3.28, 95%CI 1.30-8.25); relapse with the presence of mutation in EZH2/RUNX1/SETBP1 (sdHR 2.61, 95%CI 1.06-6.44); PFS with advancing age at HCT (per decade increment, HR 1.98, 95% 1.13-3.45); and OS with advancing age at HCT (per decade increment, HR 2.01, 95% CI 1.11-3.63) and splenomegaly at HCT/prior splenectomy (HR 2.20, 95%CI 1.04-4.65). Haploidentical donors are a viable option for HCT in MDS/MPN, especially for those disproportionately represented in the unrelated donor registry. Hence, donor mismatch should not preclude HCT for patients with MDS/MPN, an otherwise incurable malignancy. In addition to patient age, disease-related factors including splenomegaly and high-risk mutations dominate outcomes following HCT.
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Donor cell-derived genetic abnormalities after sex mismatched allogeneic cell transplantation: a unique challenge of donor cell leukemia
Klausner, M., Phan, B., Morsberger, L., Parish, R., Shane, A., Park, R., Gocke, C. D., Xian, R. R., Jones, R. J., Bolaños-Meade, J., et al
Blood cancer journal. 2023;13(1):163
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Cell-free DNA measurable residual disease as a predictor of postallogeneic hematopoietic cell transplant outcomes
Pasca, S., Guo, M. Z., Wang, S., Stokvis, K., Shedeck, A., Pallavajjala, A., Shams, C., Pallavajjala, R., DeZern, A., Varadhan, R., et al
Blood advances. 2023
Abstract
The measurable residual disease (MRD) assessment provides an attractive predictor of alloHCT outcomes. Cell-free DNA (cfDNA) has been applied to diagnosis, early detection, and disease burden monitoring in various tumors but its utility as an MRD test in myeloid malignancies has not been systematically evaluated. We sought to determine the differential sensitivity between bone marrow (BM) and cfDNA MRD and to assess the effect of cfDNA MRD on alloHCT outcomes. The technical and clinical validation cohort including 82 patients participating in clinical trials (BMT CTN-0201 and 0402) were utilized. Ultra-deep error-corrected targeted sequencing was performed on plasma and bone marrow-derived DNA. We demonstrated that 94.6% (range 93.9-95.3%) of cfDNA was derived from hematopoietic tissue. The mutant allele fraction was congruent between BM and cfDNA (rho = 0.8, p<0.0001), however, cfDNA appeared to be more sensitive in detecting clones with variant allele frequency (VAF) <0.26%. CfDNA-MRD clearance by day 90 post-alloHCT (D90) was associated with improved relapse-free survival (RFS, median survival not reached vs 5.5 months, p <0.0001) and overall survival (OS, median survival not reached vs 7.3 months, p < 0.0001) when compared to patients with persistent MRD. Irrespective of pre-alloHCT MRD, D90 cfDNA MRD was associated with inferior 2-year OS (16.7% vs. 84.8%, p <0.0001) and RFS (16.7% vs. 80.7%, p <0.0001). CfDNA appears to be an accurate, minimally invasive alternative to BM aspirates in MRD assessment and confers important prognostic implications in patients with myeloid malignancies undergoing alloHCT.
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Allogeneic Blood or Marrow Transplantation with Post-transplantation Cyclophosphamide for Peripheral T-cell Lymphoma: The Importance of Graft Source
Sterling, C. H., Hughes, M. S., Tsai, H. L., Yarkony, K., Fuchs, E. J., Swinnen, L. J., Paul, S., Bolaños-Meade, J., Luznik, L., Imus, P. H., et al
Transplantation and cellular therapy. 2022
Abstract
BACKGROUND The use of post-transplantation cyclophosphamide (PTCy) for graft-versus host-disease (GVHD) prophylaxis has revolutionized allogeneic blood or marrow transplantation (alloBMT), but there is limited published experience in peripheral T-cell lymphoma (PTCL). OBJECTIVES We sought to assess outcomes in patients with PTCL who underwent alloBMT with PTCy. STUDY DESIGN We reviewed the charts of all adult patients aged 18 years or older who underwent alloBMT with non-myeloablative conditioning and PTCy-based GVHD prophylaxis at the Sidney Kimmel Comprehensive Cancer Center between January 2004 and December 2020. RESULTS Sixty-five patients were identified. The median age was 59 years (range, 24-75 years). Lymphoma histology included PTCL-not otherwise specified (n=24), ALK-negative anaplastic large cell lymphoma (n=14), angioimmunoblastic T-cell lymphoma (n=7), enteropathy-associated T-cell lymphoma (n=6), hepatosplenic T-cell lymphoma (n=4), and other (n=10). Eleven patients were in first complete remission (CR1, 17%). The remaining patients were in first partial remission (PR1) or underwent salvage therapy to at least PR prior to transplant. Forty-eight patients received an alloBMT from a haploidentical related donor (74%), 10 from a fully matched donor (15%), and 7 from a mismatched unrelated donor (mMUD, 11%). All patients received fludarabine, cyclophosphamide, and total body irradiation (TBI). The graft source was bone marrow (BM) in 46 patients (71%) and peripheral blood (PB) in 19 patients (29%); all patients in the BM cohort received 200 cGy TBI, and most in the PB cohort (15/19) received 400 cGy TBI. GVHD prophylaxis was PTCy, mycophenolate mofetil, and a calcineurin inhibitor or sirolimus. With a median follow up of 2.8 years (range, 290 days-14.2 years), the 2-year PFS for the entire cohort was 49% (95% confidence interval [CI] 38-64%), and the 2-year OS was 55% (95% CI 44-69%). Outcomes were significantly improved in those receiving PB compared to BM, including 2-year PFS of 79% (95% CI 63-100%) vs. 39% (95% CI 27-56%), 2-year OS of 84% (95% CI 69-100%) vs. 46% (95% CI 33-63%), and 1-year cumulative incidence of (CuI) relapse of 5% (95% CI 0-16%) vs. 33% (95% CI 19-46%), with no difference in GVHD or non-relapse mortality (NRM). CONCLUSIONS AlloBMT with PTCy is safe and well-tolerated in patients with PTCL. Our data suggest increasing TBI dose to 400 cGy and using PB allografts may offer improved disease control and better survival outcomes, though additional studies are needed to confirm these findings.
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Posttransplantation Cyclophosphamide-based Graft versus Host Disease Prophylaxis with Non-myeloablative Conditioning for Blood or Marrow Transplantation for Myelofibrosis
Jain, T., Tsai, H. L., DeZern, A. E., Gondek, L. P., Elmariah, H., Bolaños-Meade, J., Luznik, L., Fuchs, E., Ambinder, R., Gladstone, D. E., et al
Transplantation and cellular therapy. 2022
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Editor's Choice
Abstract
We describe outcomes with posttransplantation cyclophosphamide and non-myeloablative conditioning based allogeneic blood or marrow transplantation for myelofibrosis using matched or mismatched, family or unrelated donors. The conditioning regimen consisted of fludarabine, cyclophosphamide and total body irradiation. Forty-two patients, with a median age of 63 years, were included, of whom 19% had intermediate-1, 60% had intermediate-2, and 21% had high-risk DIPSS-plus disease, and 60% had atleast one high-risk somatic mutation. Over 90% patients engrafted neutrophils at a median of 19.5 days and 7% had graft failure. At 1 and 3-years, respectively, the overall survival was 65% and 60%, relapse-free survival was 65% and 31%, relapse was 5% and 40%, and non-relapse mortality was 30% and 30%. Acute graft versus host disease grade 3-4 was noted in 17% at 1 year and chronic graft versus host disease requiring systemic therapy in 12% patients. Spleen size ≥ 17 cm or prior splenectomy was associated with inferior relapse-free survival (HR 3.50, 95% CI 1.18-10.37, P=0.02) and higher relapse rate (SDHR not calculable, P=0.01). Age > 60 years (SDHR 0.26, 95% CI: 0.08-0.80, P=0.02) and peripheral blood graft (SDHR 0.34, 95% CI 0.11-0.99, P=0.05) was associated with lower risk of relapse. In our limited sample, the presence of a high-risk mutation was not statistically significantly associated with an inferior outcome although ASXL1 was suggestive of inferior survival (SDHR 2.36. 95% CI 0.85-6.6, P=0.09). Overall, this approach shows comparable outcomes as previously reported and underscores the importance of spleen size in evaluation of transplant candidates.
PICO Summary
Population
Patients with high-risk Dynamic International Prognostic Scoring System (DIPSS)-plus myelofibrosis (n=42)
Intervention
Matched or mismatched allogeneic transplantation with non-myeloablative conditioning, and post-transplant cyclophosphamide
Comparison
None
Outcome
Over 90% patients engrafted neutrophils at a median of 19.5 days and 7% had graft failure. At 1 and 3-years, respectively, the overall survival was 65% and 60%, relapse-free survival was 65% and 31%, relapse was 5% and 40%, and non-relapse mortality was 30% and 30%. Acute graft versus host disease grade 3-4 was noted in 17% at 1 year and chronic graft versus host disease requiring systemic therapy in 12% patients. Spleen size ≥ 17 cm or prior splenectomy was associated with inferior relapse-free survival (HR 3.50, 95% CI 1.18-10.37) and higher relapse rate (SDHR not calculable). Age > 60 years (SDHR 0.26, 95% CI: 0.08-0.80) and peripheral blood graft (SDHR 0.34, 95% CI 0.11-0.99) was associated with lower risk of relapse. In our limited sample, the presence of a high-risk mutation was not statistically significantly associated with an inferior outcome although ASXL1 was suggestive of inferior survival (SDHR 2.36. 95% CI 0.85-6.6).
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Allogeneic blood or marrow transplantation with haploidentical donor and post-transplantation cyclophosphamide in patients with myelofibrosis: a multicenter study
Kunte, S., Rybicki, L., Viswabandya, A., Tamari, R., Bashey, A., Keyzner, A., Iqbal, M., Grunwald, M. R., Dholaria, B., Elmariah, H., et al
Leukemia. 2022;36(3):856-864
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Abstract
We report the results from a multicenter retrospective study of 69 adult patients who underwent haploidentical blood or marrow transplantation (haplo-BMT) with post-transplantation cyclophosphamide (PTCy) for chronic phase myelofibrosis. The median age at BMT was 63 years (range, 41-74). Conditioning regimens were reduced intensity in 54% and nonmyeloablative in 39%. Peripheral blood grafts were used in 86%. The median follow-up was 23.1 months (range, 1.6-75.7). At 3 years, the overall survival, relapse-free survival (RFS), and graft-versus-host-disease (GVHD)-free-RFS were 72% (95% CI 59-81), 44% (95% CI 29-59), and 30% (95% CI 17-43). Cumulative incidences of non-relapse mortality and relapse were 23% (95% CI 14-34) and 31% (95% CI 17-47) at 3 years. Spleen size ≥22 cm or prior splenectomy (HR 6.37, 95% CI 2.02-20.1, P = 0.002), and bone marrow grafts (HR 4.92, 95% CI 1.68-14.4, P = 0.004) were associated with increased incidence of relapse. Cumulative incidence of acute GVHD grade 3-4 was 10% at 3 months and extensive chronic GVHD was 8%. Neutrophil engraftment was reported in 94% patients, at a median of 20 days (range, 14-70). In conclusion, haplo-BMT with PTCy is feasible in patients with myelofibrosis. Splenomegaly ≥22 cm and bone marrow grafts were associated with a higher incidence of relapse in this study.
Clinical Commentary
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NIHMS1867052
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What are the implications for practice and for future work?
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Haploidentical bone marrow transplantation in patients with relapsed or refractory severe aplastic anaemia in the USA (BMT CTN 1502): a multicentre, single-arm, phase 2 trial
DeZern, A. E., Eapen, M., Wu, J., Talano, J. A., Solh, M., Dávila Saldaña, B. J., Karanes, C., Horwitz, M. E., Mallhi, K., Arai, S., et al
The Lancet. Haematology. 2022
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Editor's Choice
Abstract
BACKGROUND Relapsed severe aplastic anaemia is a marrow failure disorder with high morbidity and mortality. It is often treated with bone marrow transplantation at relapse post-immunosuppressive therapy, but under-represented minorities often cannot find a suitably matched donor. This study aimed to understand the 1-year overall survival in patients with relapsed or refractory severe aplastic anaemia after haploidentical bone marrow transplantation. METHODS We report the outcomes of BMT CTN 1502, a single-arm, phase 2 clinical trial done at academic bone marrow transplantation centres in the USA. Included patients were children and adults (75 years or younger) with severe aplastic anaemia that was refractory (fulfilment of severe aplastic anaemia disease criteria at least 3 months after initial immunosuppressive therapy) or relapsed (initial improvement of cytopenias after first-line immunosuppressive therapy but then a later return to fulfilment of severe aplastic anaemia disease criteria), adequate performance status (Eastern Cooperative Oncology Group score 0 or 1, Karnofsky or Lansky score ≥60%), and the presence of an eligible related haploidentical donor. The regimen used reduced-intensity conditioning (rabbit anti-thymocyte globulin 4·5 mg/kg in total, cyclophosphamide 14·5 mg/kg daily for 2 days, fludarabine 30 mg/kg daily for 5 days, total body irradiation 200 cGy in a single fraction), related HLA-haploidentical donors, and post-transplantation cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis. Additionally, for GVHD prophylaxis, mycophenolate mofetil was given orally at a dose of 15 mg/kg three times a day up to 1 g three times a day (maximum dose 3000 mg per day) from day 5 to day 35, and tacrolimus was given orally or intravenously from day 5 to day 180 as per institutional standards to maintain a serum concentration of 10-15 ng/mL. The primary endpoint was overall survival 1 year after bone marrow transplantation. All patients treated per protocol were analysed. This study is complete and is registered with ClinicalTrials.gov, NCT02918292. FINDINGS Between May 1, 2017, and Aug 30, 2020, 32 patients with relapsed or refractory severe aplastic anaemia were enrolled from 14 centres, and 31 underwent bone marrow transplantation. The median age was 24·9 years (IQR 10·4-51·3), and median follow-up was 24·3 months (IQR 12·1-29·2). Of the 31 patients who received a transplant, 19 (61%) were male and 12 (39%) female. 13 (42%) patients were site-reported as non-White, and 19 (61%) were from under-represented racial and ethnic groups; there were four (13%) patients who were Asian, seven (23%) Black, one (3%) Hawaiian/Pacific Islander, and one (3%) more than one race, with seven (23%) patients reporting Hispanic ethnicity. 24 (77%) of 31 patients were alive with engraftment at 1 year, and one (3%) patient alive with autologous recovery. The 1-year overall survival was 81% (95% CI 62-91). The most common grade 3-5 adverse events (seen in seven or more patients) included seven (23%) patients with abnormal liver tests, 15 (48%) patients with cardiovascular changes (including sinus tachycardia, heart failure, pericarditis), ten (32%) patients with gastrointestinal issues, seven (23%) patients with nutritional disorders, and eight (26%) patients with respiratory disorders. Six (19%) deaths, due to disease and unsuccessful bone marrow transplantation, were reported after transplantation. INTERPRETATION Haploidentical bone marrow transplantation using this approach results in excellent overall survival with minimal GVHD in patients who have not responded to immunosuppressive therapy, and can expand access to bone marrow transplantation across all populations. In clinical practice, this could now be considered a standard approach for salvage treatment of severe aplastic anaemia. Attention to obtaining high cell doses (>2·5 × 10(8) nucleated marrow cells per kg of recipient ideal bodyweight) from bone marrow harvests is crucial to the success of this approach. FUNDING US National Heart, Lung, and Blood Institute and US National Cancer Institute.
PICO Summary
Population
Children and adults up to 75 years with severe refractory aplastic anaemia, from transplant centres in USA (n=32)
Intervention
Haploidentical transplantation with reduced intensity conditioning
Comparison
None
Outcome
31 received transplant. 24 (77%) of 31 patients were alive with engraftment at 1 year, and one (3%) patient alive with autologous recovery. The 1-year overall survival was 81% (95% CI 62-91). The most common grade 3-5 adverse events (seen in seven or more patients) included seven (23%) patients with abnormal liver tests, 15 (48%) patients with cardiovascular changes (including sinus tachycardia, heart failure, pericarditis), ten (32%) patients with gastrointestinal issues, seven (23%) patients with nutritional disorders, and eight (26%) patients with respiratory disorders. Six (19%) deaths, due to disease and unsuccessful bone marrow transplantation, were reported after transplantation.
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Outcome of donor-derived TAA T cell therapy in patients with high-risk or relapsed acute leukemia post allogeneic BMT
Kinoshita, H., Cooke, K. R., Grant, M., Stanojevic, M., Cruz, C. R. Y., Keller, M. D., Fortiz, M. F., Hoq, F., Lang, H., Barrett, A. J., et al
Blood advances. 2022
Abstract
Patients with hematologic malignancies relapsing after allogeneic blood or marrow transplantation (BMT) have limited response to conventional salvage therapies with an expected 1-year overall survival (OS) of <20%. We evaluated the safety and clinical outcomes following administration of a novel T-cell therapeutic targeting three tumor associated antigens (TAA-T) in patients with acute leukemia who relapsed or were at high-risk of relapse after allogeneic BMT. Lymphocytes obtained from the BMT donor were manufactured to target TAAs; WT1, PRAME and survivin, which are over-expressed and immunogenic in most hematologic malignancies. Patients received TAA-T infusions at doses of 0.5-4x107/m2. Twenty-three BMT recipients with relapsed/refractory (n=11) and/or high-risk (n=12) acute myeloid leukemia (n=20) and acute lymphoblastic leukemia (n=3) were infused post-transplant. No patient developed cytokine-release syndrome or neurotoxicity, and only one patient developed grade III GVHD. Of the patients who relapsed post-BMT and received bridging therapy, the majority (n=9/11) achieved complete hematologic remission before receiving TAA-T. Relapsed patients exhibited a 1-year OS of 36% and 1-year leukemia-free survival of 27.3% post-TAA-T. The poorest prognosis patients (relapsed <6 months after transplant) exhibited a 1-year OS of 42.8% post-relapse (n=7). Median survival was not reached for high-risk patients who received pre-emptive TAA-T post-transplant (n=12). Although as a Phase-I study concomitant anti-leukemic therapy was allowed, TAA-T were safe and well-tolerated and sustained remissions in high-risk and relapsed patients were observed. Moreover, adoptively transferred TAA-T detected by T-cell receptor V-beta (TCRVb) sequencing persisted up to at least 1 year post-infusion. (ClinicalTrials.gov numbers, NCT002203902).
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10.
Allogeneic Blood or Marrow Transplantation with High-Dose Post-transplantation Cyclophosphamide for Acute Lymphoblastic Leukemia in Patients Aged ≥55
Webster, J. A., Reed, M., Tsai, H. L., Ambinder, A., Jain, T., Dezern, A. E., Levis, M. J., Showel, M. M., Prince, G. T., Hourigan, C. S., et al
Transplantation and cellular therapy. 2022
Abstract
BACKGROUND Patients ≥55 years-old with acute lymphoblastic leukemia (ALL) fare poorly with conventional chemotherapy with 5-year overall survival of ∼20%. Tyrosine kinase inhibitors and novel B-cell targeted therapies improve outcomes, but rates of relapse and death in remission remain high. Allogeneic blood or marrow transplantation (AlloBMT) provides an alternative consolidation strategy, and post-transplantation cyclophosphamide (PTCy) facilitates HLA-mismatched transplants with low rates of non-relapse mortality (NRM) and graft-versus-host disease (GVHD). METHODS The transplant database at Johns Hopkins was queried for patients ≥ 55 years old who received alloBMT for ALL using PTCy. FINDINGS The database included 77 such patients. Most received reduced-intensity conditioning (RIC) (88.3%), were in first remission (CR1) (85.7%), and had B-lineage disease (90.9%). For the entire cohort, 5-year relapse-free survival (RFS) and overall survival (OS) were 46% (95% CI 34-57) and 49% (95% CI 37-60). Grade 3-4 acute GVHD occurred in only 3% of patients and chronic GVHD in 13%. In multivariable analysis, myeloablative conditioning led to worse RFS (HR 4.65, p=0.001); while transplant in CR1 (HR 0.30, p=0.004), and transplant for Ph+ ALL vs. T ALL (HR 0.29, p=0.03) improved RFS. Of the 54 patients who received RIC alloBMT in CR1 for B ALL, 5-year RFS and OS were 62% (95% CI 47-74) and 65% (95% CI 51-77), respectively, with a 5-year relapse incidence of 16% (95% CI 7-27) and NRM of 24% (95% CI 13-36). INTERPRETATION RIC AlloBMT with PTCy in CR1 represents a promising consolidation strategy for B ALL patients ≥ 55 years old. FUNDING NIH grants P01 CA225618 and P30 CA06973.