Bejanyan, Nelli

Abstract Background: Acute myeloid leukemia (AML) with TP53 alteration (TP53alt), including deletion (TP53del) detected by cytogenetics (CG) (karyotype, FISH, or genomic microarray) and/or TP53 mutation (TP53mut) identified by next-generation sequencing, is associated with poor prognosis. However, a subset of patients may achieve long-term survival after allogeneic hematopoietic cell transplantation (allo-HCT). Patient-, disease-, and transplant-related variables may inform risk stratification and improve treatment decision-making in this high-risk population. We used the CIBMTR registry to investigate outcomes of patients with TP53alt AML undergoing allo-HCT. Methods: We included adult patients with 2017 ELN adverse-risk AML who underwent first allo-HCT between 2013–2019 and had available CG and molecular data. TP53del was centrally reviewed by expert cytogeneticist. Patients were stratified into three TP53alt groups: Group 1 (TP53mut+/ TP53del+), Group 2 (TP53mut −/ TP53del+), and Group 3 (TP53mut+/ TP53del −). The control group comprised patients with 2017 ELN adverse-risk AML negative for both TP53mut and TP53del. Patients from embargoed centers, lacking consent or comprehensive research data, or missing CG and molecular information were excluded. Results: Of 6,474 patients with adverse-risk AML, 703 patients with TP53alt met inclusion criteria: Group 1 (n=203), Group 2 (n=271), Group 3 (n=229). The control group included 2,763 patients. Median age was 58 years (44% ≥60); 44% were female; 16% had Karnofsky score <90, and 52% had HCT-CI ≥3. Secondary AML was more frequent in TP53alt groups (32%, 27%, 27%) versus control (21%) (p<.01). Complex and monosomal karyotypes were most common in Group 1 (61%), followed by Group 2 (54%), Group 3 (31%), and control (6%), p<.01. More patients in Groups 1 and 2 (28% each) underwent HCT in primary induction failure/relapse (PIF/Rel) versus Group 3 (19%) and control (19%), p<.01. Median time from diagnosis to transplant was 5 months (1-331). Donor type was matched related in 23%, matched or mismatched unrelated in 50%, haploidentical in 18%, and umbilical cord blood in 7%. Conditioning intensity was myeloablative (MA) in 51%; reduced-intensity (RIC) in 36% , and 13% non-MA (NMA). Post-transplant cyclophosphamide (PTCy) was used in 27%; and in vivo T-cell depletion (ATG or alemtuzumab) in 26%. After median follow-up of 66 months (3-130), 5-yr OS was 18% (Group 1), 18% (Group 2), 35% (Group 3) vs 46% in controls (p<0.001). 5-yr LFS was 14%, 15%, and 28%, respectively, vs 38% (p<0.001). 5-yr CIR was 69%, 66%, and 52% vs 43% (p<0.001). Transplant-related mortality (TRM) was similar across groups (1-year: 12–16%). On multivariate analysis, compared with controls, TP53del (with or without TP53mut) was independently associated with higher relapse risk: Group 1 HR 1.97, Group 2 HR 1.91, Group 3 HR 1.45 (all p<0.001). These findings translated into inferior OS (HR 1.94, 1.87, and 1.45, respectively, p<0.001). PIF/Rel and CR2+ were also associated with worse survival (HR 2.58 (p<0.001) and 1.18 (p<0.001, respectively). No significant difference was observed between MA and RIC for relapse, while non-myeloablative regimens (HR 1.65; p<0.001) were associated with higher CIR. In vivo T-cell depletion increased relapse risk (HR 1.22; p=0.004). TRM was not influenced by TP53alt status; it was impacted by age, KPS, time from diagnosis to HCT, and GVHD prophylaxis regiment (non-PTCy). Conclusions: This large, registry-based study with long term median follow-up showed that among patients with adverse-risk AML, TP53alt is a strong independent predictor of poor post-HCT outcomes in AML, particularly when TP53del is present. Patients with TP53del , with or without concurrent TP53mut, experienced the worst outcomes, followed by those with isolated TP53mut. Despite the limitations of registry data including lack of information on timing of TP53mut, variant allele frequency (VAF), number of mutations, or accurate information on measurable residual disease (MRD), these findings reinforce the adverse prognostic impact of TP53alt and support its inclusion in risk stratification frameworks. While some patients with TP53alt —particularly those with isolated mutations—may benefit from allo-HCT, relapse remains the dominant cause of failure. Future studies incorporating TP53 functional status, VAF, clonal architecture, specific CG, MRD, and novel transplant approaches are warranted.

Abstract We evaluate the impact of donor types on outcomes of hematopoietic cell transplantation (HCT) in myelofibrosis, using the Center for International Blood and Marrow Transplant Research registry data for HCTs done between 2013 and 2019. In all 1597 patients, the use of haploidentical donors increased from 3% in 2013 to 19% in 2019. In study-eligible 1032 patients who received peripheral blood grafts for chronic-phase myelofibrosis, 38% of recipients of haploidentical HCT were non-White/Caucasian. Matched sibling donor (MSD)–HCTs were associated with superior overall survival (OS) in the first 3 months (haploidentical hazard ratio [HR], 5.80 [95% confidence interval (CI), 2.52-13.35]; matched unrelated (MUD) HR, 4.50 [95% CI, 2.24-9.03]; mismatched unrelated HR, 5.13 [95% CI, 1.44-18.31]; P < .001). This difference in OS aligns with lower graft failure with MSD (haploidentical HR, 6.11 [95% CI, 2.98-12.54]; matched unrelated HR, 2.33 [95% CI, 1.20-4.51]; mismatched unrelated HR, 1.82 [95% CI, 0.58-5.72]). There was no significant difference in OS among haploidentical, MUD, and mismatched unrelated donor HCTs in the first 3 months. Donor type was not associated with differences in OS beyond 3 months after HCT, relapse, disease-free survival, or OS among patients who underwent HCT within 24 months of diagnosis. Patients who experienced graft failure had more advanced disease and commonly used nonmyeloablative conditioning. Although MSD-HCTs were superior, there is no significant difference in HCT outcomes from haploidentical and MUDs. These results establish haploidentical HCT with posttransplantation cyclophosphamide as a viable option in myelofibrosis, especially for ethnic minorities underrepresented in the donor registries.

Abstract Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

Abstract Standard initial therapy of chronic graft vs. host disease (cGVHD) with glucocorticoids results in suboptimal response. Safety and feasibility of therapy with ofatumumab (1000 mg IV on days 0 and 14) and prednisone (1 mg/kg/day) was previously established in our phase I trial (n = 12). We now report the mature results of the phase II expansion of the trial (n = 38). The overall NIH severity of cGVHD was moderate (63%) or severe (37%) with 74% of all patients affected by the overlap subtype of cGVHD and 82% by prior acute cGVHD. The observed 6 month clinician-reported and 2014 NIH-defined overall response rates (ORR = complete + partial response [CR/PR]) of 62.5% (1-sided lower 90% confidence interval=51.5%) were not superior to pre-specified historic benchmark of 60%. Post-hoc comparison of 6 month NIH response suggested benefit compared to more contemporaneous NIH-based benchmark of 48.6% with frontline sirolimus/prednisone (CTN 0801 trial). Baseline cGVHD features (organ involvement, severity, initial immune suppression agents) were not significantly associated with 6-month ORR. The median time to initiation of second-line therapy was 5.4 months (range 0.9-15.1 months). Failure-free survival (FFS) was 64.2% (95% CI 46.5-77.4%) at 6 months and 53.1% (95% CI 35.8-67.7%) at 12 months, whereas FFS with CR/PR at 12 months of 33.5% exceeded a benchmark of 15% in post-hoc analysis, and was associated with greater success in steroid discontinuation by 24 months (odds ratio 8 (95% CI 1.21-52.7). This single-arm phase II trial demonstrated acceptable safety and potential efficacy of the upfront use of ofatumumab in combination with prednisone in cGVHD. This trial was registered at www.clinicaltrials.gov as #NCT01680965.

Abstract Little is known about whether risk classification at diagnosis predicts post-hematopoietic cell transplantation (HCT) outcomes in patients with acute myeloid leukemia (AML). We evaluated 8709 patients with AML from the CIBMTR database, and after selection and manual curation of the cytogenetics data, 3779 patients in first complete remission were included in the final analysis: 2384 with intermediate-risk, 969 with adverse-risk, and 426 with KMT2A-rearranged disease. An adjusted multivariable analysis detected an increased risk of relapse for patients with KMT2A-rearranged or adverse-risk AML as compared to those with intermediate-risk disease (hazards ratio [HR], 1.27; P = .01; HR, 1.71; P < .001, respectively). Leukemia-free survival was similar for patients with KMT2A rearrangement or adverse risk (HR, 1.26; P = .002, and HR, 1.47; P < .001), as was overall survival (HR, 1.32; P < .001, and HR, 1.45; P < .001). No differences in outcome were detected when patients were stratified by KMT2A fusion partner. This study is the largest conducted to date on post-HCT outcomes in AML, with manually curated cytogenetics used for risk stratification. Our work demonstrates that risk classification at diagnosis remains predictive of post-HCT outcomes in AML. It also highlights the critical need to develop novel treatment strategies for patients with KMT2A-rearranged and adverse-risk disease.

SummaryReduced‐intensity conditioning (RIC) allogeneic haematopoietic cell transplantation (allo‐HCT) is a curative option for select relapsed/refractory Hodgkin lymphoma (HL) patients; however, there are sparse data to support superiority of any particular conditioning regimen. We analyzed 492 adult patients undergoing human leucocyte antigen (HLA)‐matched sibling or unrelated donor allo‐HCT for HL between 2008 and 2016, utilizing RIC with either fludarabine/busulfan (Flu/Bu), fludarabine/melphalan (Flu/Mel140) or fludarabine/cyclophosphamide (Flu/Cy). Multivariable regression analysis was performed using a significance level of <0·01. There were no significant differences between regimens in risk for non‐relapse mortality (NRM) (P = 0·54), relapse/progression (P = 0·02) or progression‐free survival (PFS) (P = 0·14). Flu/Cy conditioning was associated with decreased risk of mortality in the first 11 months after allo‐HCT (HR = 0·28; 95% CI = 0·10–0·73; P = 0·009), but beyond 11 months post allo‐HCT it was associated with a significantly higher risk of mortality, (HR = 2·46; 95% CI = 0·1.32–4·61; P = 0·005). Four‐year adjusted overall survival (OS) was similar across regimens at 62% for Flu/Bu, 59% for Flu/Mel140 and 55% for Flu/Cy (P = 0·64), respectively. These data confirm the choice of RIC for allo‐HCT in HL does not influence risk of relapse, NRM or PFS. Although no OS benefit was seen between Flu/Bu and Flu/Mel 140; Flu/Cy was associated with a significantly higher risk of mortality beyond 11 months from allo‐HCT (possibly due to late NRM events).

Background Although rituximab‐based high‐dose therapy is frequently used in diffuse large B cell lymphoma (DLBCL) patients undergoing autologous hematopoietic cell transplantation (auto‐HCT), data supporting the benefits are not available. Herein, we report the impact of rituximab‐based conditioning on auto‐HCT outcomes in patients who have DLBCL. Methods Using the Center for International Blood and Marrow Transplant Research (CIBMTR) registry, 862 adult DLBCL patients undergoing auto‐HCT between 2003 and 2017 using BEAM (BCNU, etoposide, cytarabine, melphalan) conditioning regimen were included. All patients received frontline rituximab‐containing chemoimmunotherapy and had chemosensitive disease pre‐HCT. Early chemoimmunotherapy failure was defined as not achieving complete remission (CR) after frontline chemoimmunotherapy or relapse within 1 year of initial diagnosis. The primary outcome was overall survival (OS). Results The study cohort was divided into 2 groups: BEAM (n = 667) and R‐BEAM (n = 195). On multivariate analysis, no significant difference was seen in OS ( P = .83) or progression‐free survival (PFS) ( P = .61) across the 2 cohorts. No significant association between the use of rituximab and risk of relapse ( P = .15) or nonrelapse mortality ( P = .12) was observed. Variables independently associated with lower OS included older age at auto‐HCT ( P < .001), absence of CR at auto‐HCT ( P < .001) and early chemoimmunotherapy failure ( P < .001). Older age ( P < .0002) and non‐CR pre‐HCT ( P < .0001) were also associated with inferior PFS. There was no significant difference in early infectious complications between the 2 cohorts. Conclusion In this large registry analysis of DLBCL patients undergoing auto‐HCT, the addition of rituximab to the BEAM conditioning regimen had no impact on transplantation outcomes. Older age, absence of CR pre auto‐HCT, and early chemoimmunotherapy failure were associated with inferior survival.

Although some data (Scott, JCO 2017) suggest that myeloablative conditioning (MAC) is preferred for allogeneic hematopoietic cell transplantation (HCT) in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), these data were not informed by analysis of disease specific risk factors. We analyzed AML and MDS HCT outcomes stratified by the disease risk index (DRI) in order to identify the preferred transplant conditioning intensity (reduced-intensity conditioning [RIC] vs. MAC). In this large CIBMTR registry study we identified 4387 adult patients (age 40-65 years) who received HCT for AML (68%) or MDS (32%) between 2009 and 2015. DRI was stratified as low/ intermediate risk (1539 MAC and 999 RIC) and high/ very high risk (1121 MAC and 728 RIC). Examining the low/ intermediate risk DRI cohort (Table), RIC was associated with lower risk of TRM (HR=0.74, 95% CI 0.62-0.88; p<0.001) but significantly higher risk of relapse (HR=1.54, 95% CI 1.35-1.76; p<0.001). As a result, RFS in this cohort was significantly worse with RIC (HR=1.19, 95% CI 1.07-1.33; p=0.001). In the high/ very high risk DRI cohort, RIC resulted in similar TRM (HR=0.83, 95% CI 0.68-1.00; p=0.051) but again significantly higher risk of relapse (HR=1.23, 95% CI 1.08-1.41; p=0.002). RFS in high/ very high risk DRI cohort was similar between RIC and MAC. Adjusted outcome curves for the 3 endpoints are shown in the Figure. In this large study of HCT for AML or MDS stratified by DRI, RIC was independent predictor of lower TRM, but significantly higher risk of relapse. The MAC was an independent predictor of lower relapse in both low/ intermediate and high/very high DRI groups. However, MAC only resulted in RFS benefit in the low/ intermediate group where the magnitude of impact on relapse was not offset by the higher TRM. In adults with AML or MDS aged 40-65 years, these data support MAC as the preferred conditioning intensity for low/ intermediate risk DRI, whereas MAC does not provide significant benefit in those with high/ very high risk DRI. Safer, yet still potent MAC regimens could benefit this higher risk group. Disclosures Bejanyan: Kiadis Pharma: Other: advisory board. Brunstein:Gamida: Research Funding; Astex: Research Funding; Magenta: Research Funding. Kebriaei:Amgen: Research Funding; Jazz: Consultancy; Pfizer: Honoraria; Kite: Honoraria; Pfizer: Honoraria; Kite: Honoraria. Weisdorf:Fate Therapeutics: Consultancy; Pharmacyclics: Consultancy; Incyte: Research Funding.

Abstract Total body irradiation (TBI)-based conditioning regimens are considered the standard of care for patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic cell transplantation (HCT). However, due to concerns regarding acute and long-term toxicities, non-TBI regimens, commonly including busulfan (BU), have been increasingly explored. We performed a retrospective cohort analysis with the hypothesis that there would be equivalence of these two myeloablative approaches by reviewing outcomes for adult patients (pts), aged 18-60 years, undergoing a first, well-matched sibling, related or unrelated donor HCT in CR1 or CR2 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 2005-2014. Eight hundred nineteen pts received TBI (63% 9-12 Gy, 37% ≥13 Gy) combined with etoposide (25%) or cyclophosphamide (Cy) (75%) and 299 pts received intravenous BU combined with a second alkylator Cy (15%) or melphalan (Mel) (13%), or a nucleoside analogue fludarabine (Flu) (41%) or clofarabine (Clo)(30%). The majority of the BU-based pts were treated at the Moffitt or MD Anderson Cancer Center. The BU-based regimens were grouped together for analyses since no significant differences in basic outcomes among the different chemotherapy-only regimens were noted. Patients in the BU-containing group were older but had better performance status, took longer to achieve CR1 and longer to receive HCT; more received peripheral blood than marrow grafts, peri-HCT ATG, pre- and post HCT tyrosine kinase inhibitors ( TKI), and were treated more recently than pts in the TBI-based group (Table 1). With median follow-up of 3.6 years for the BU-based group and 5.3 years for the TBI-based group, adjusted 3 year outcomes showed treatment-related mortality (TRM) BU 19% vs. TBI 25% (p=.04); relapse BU 37% vs. TBI 28% (p=.007); disease-free survival (DFS) Bu 45% vs. TBI 48% (p=.35); and overall survival (OS) BU 57% vs. TBI 53% (p=.35) (Figures A-B). Patients in the BU group had significantly more grade II-IV acute GVHD (47% vs. 40%, p=.025), but marginally less chronic GVHD (49% vs. 55% at 3 years, p=.073). In multivariate analysis, the BU group had a significantly higher rate of acute GVHD after day 50 (RR 1.75, 95% CI 1.19-2.58, p=.004), but marginally less chronic GVHD (RR 0.83, 95% CI 0.68-1.01 p=.059) and higher risk of relapse (RR 1.46, 95% CI 1.15-1.85 p=.002) compared with TBI-based regimens. Despite the observed higher risks of acute GVHD and relapse, BU-based conditioning led to similar TRM, OS, and DFS following HCT for ALL. Table 1 Table 1. Figure Figure. Disclosures Ciurea: Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership. Seftel:Otsuka: Research Funding. Pulsipher:Medac: Other: Housing support for conference; Chimerix: Consultancy; Jazz Pharmaceutical: Consultancy; Novartis: Consultancy, Other: Study Steering Committee. Champlin:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

Abstract HLA-haploidentical hematopoietic cell transplantation (Haplo-HCT) using posttransplantation cyclophosphamide (PT-Cy) has improved donor availability. However, a matched sibling donor (MSD) is still considered the optimal donor. Using the Center for International Blood and Marrow Transplant Research database, we compared outcomes after Haplo-HCT vs MSD in patients with acute myeloid leukemia (AML) in first complete remission (CR1). Data from 1205 adult CR1 AML patients (2008-2015) were analyzed. A total of 336 patients underwent PT-Cy–based Haplo-HCT and 869 underwent MSD using calcineurin inhibitor–based graft-versus-host disease (GVHD) prophylaxis. The Haplo-HCT group included more reduced-intensity conditioning (65% vs 30%) and bone marrow grafts (62% vs 7%), consistent with current practice. In multivariable analysis, Haplo-HCT and MSD groups were not different with regard to overall survival (P = .15), leukemia-free survival (P = .50), nonrelapse mortality (P = .16), relapse (P = .90), or grade II-IV acute GVHD (P = .98). However, the Haplo-HCT group had a significantly lower rate of chronic GVHD (hazard ratio, 0.38; 95% confidence interval, 0.30-0.48; P &lt; .001). Results of subgroup analyses by conditioning intensity and graft source suggested that the reduced incidence of chronic GVHD in Haplo-HCT is not limited to a specific graft source or conditioning intensity. Center effect and minimal residual disease–donor type interaction were not predictors of outcome. Our results indicate a lower rate of chronic GVHD after PT-Cy–based Haplo-HCT vs MSD using calcineurin inhibitor–based GVHD prophylaxis, but similar other outcomes, in patients with AML in CR1. Haplo-HCT is a viable alternative to MSD in these patients.