Clonal hematopoiesis-derived therapy-related myeloid neoplasms after autologous hematopoietic stem cell transplant for lymphoid and non-lymphoid disorders.

Therapy-related myeloid neoplasms (tMN) are complications of cytotoxic therapies. Risk of tMN is high in recipients of autologous hematopoietic stem cell transplantation (aHSCT). Acquisition of genomic mutations represents a key pathogenic driver but the origins, timing and dynamics, particularly in the context of preexisting or emergent clonal hematopoiesis (CH), have not been sufficiently clarified. We studied a cohort of 1507 patients undergoing aHSCT and a cohort of 263 patients who developed tMN without aHSCT to determine clinico-molecular features unique to post-aHSCT tMN. We show that tMN occurs in up to 2.3% of patients at median of 2.6 years post-AHSCT. Age ≥ 60 years, male sex, radiotherapy, high treatment burden ( ≥ 3 lines of chemotherapy), and graft cellularity increased the risk of tMN. Time to evolution and overall survival were shorter in post-aHSCT tMN vs. other tMN, and the earlier group's mutational pattern was enriched in PPM1D and TP53 lesions. Preexisting CH increased the risk of adverse outcomes including post-aHSCT tMN. Particularly, antecedent lesions affecting PPM1D and TP53 predicted tMN evolution post-transplant. Notably, CH-derived tMN had worse outcomes than non CH-derived tMN. As such, screening for CH before aHSCT may inform individual patients' prognostic outcomes and influence their prospective treatment plans. Presented in part as an oral abstract at the 2022 American Society of Hematology Annual Meeting, New Orleans, LA, 2022.

Tacrolimus/methotrexate vs tacrolimus/reduced-dose methotrexate/mycophenolate for graft-versus-host disease prevention.

Tacrolimus (Tac)/methotrexate (MTX) is standard graft-versus-host disease (GVHD) prophylaxis; however, is associated with several toxicities. Tac, reduced-dose MTX (mini-MTX), and mycophenolate mofetil (MMF) have been used but never compared with standard MTX. We performed a randomized trial comparing Tac/MTX (full-MTX) with Tac/mini-MTX/MMF (mini-MTX/MMF) for GVHD prevention after allogeneic hematopoietic cell transplantation (HCT). Patients (pts) receiving first myeloablative HCT using an 8/8 HLA-matched donor were eligible. Primary end points were incidence of acute GVHD (aGVHD), mucositis, and engraftment. Secondary end points included chronic GVHD (cGVHD), organ toxicity, infection, relapse, nonrelapse mortality (NRM), and overall survival (OS). Ninety-six pts were randomly assigned to full-MTX (N = 49) or mini-MTX (N = 47). The majority (86%) used bone marrow grafts. There was no significant difference in grade 2-4 aGVHD (28% mini-MTX/MMF vs 27% full-MTX; P = .41); however higher incidence of grade 3-4 aGVHD (13% vs 4%; P = .07) with mini-MTX/MMF. Pts receiving mini-MTX/MMF had lower grade 3 or 4 mucositis and faster engraftment. There were no differences in moderate-to-severe cGVHD at 1 year or infections. Pts receiving mini-MTX/MMF experienced less nephrotoxicity and respiratory failure. There was no difference in the 1-year relapse (19% vs 21%; P = .89) and OS (72% vs 71%; P = .08), and mini-MTX/MMF was associated with lower but nonsignificant NRM (11% vs 22%; P = .06). Compared with full-MTX, mini-MTX/MMF was associated with no difference in grade 2-4 aGVHD and a more favorable toxicity profile. The higher severe aGVHD warrants further study to optimize this regimen. The trial was registered at www.clinicaltrials.gov as #NCT01951885.

A Pilot Trial of Patient-Reported Outcomes for Acute Graft-Versus-Host-Disease.

Acute graft-versus-host disease (GVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Acute GVHD is associated with severe physical and psychosocial symptoms. We sought to evaluate the feasibility of capturing patient-reported outcome (PRO) measures in acute GVHD to better measure symptom burden and quality of life (QOL). We conducted a pilot study of adult patients undergoing first allogeneic HCT. Questions from Functional Assessment of Cancer Therapy-Bone Marrow Transplantation (FACT-BMT), Patient-Reported Outcomes Measurement Information System (PROMIS-10), and Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) were selected, and the survey was administered electronically before HCT, at days 14, 50, and 100 after HCT. In addition, patients who developed grade 2-4 acute GVHD received it weekly for 4 weeks and then monthly up to 3 months. From 2018 to 2020, 73 patients were consented, of which 66 went on to undergo HCT and were included in the analysis. Median age at transplantation was 63 years, and 92% were Caucasian. Only 47% of expected surveys were completed (range 0%-67% for each time point). Descriptive exploratory analysis demonstrate an expected trajectory of QOL using the FACT-BMT and PROMIS-10 scores throughout transplantation. Patients who developed acute GVHD (N = 15) generally had lower QOL scores compared to those with no or mild GVHD post-HCT. The PRO-CTCAE captured several physical and mental/emotional symptoms in all patients and those with GVHD. Fatigue (100%), decreased appetite (92%), problem tasting (85%), loose stools (77%), pain (77%), skin itching (77%), and depression (feeling sad) (69%) were the most prevalent symptoms among patients with grade 2-4 acute GVHD. Patients with acute GVHD generally reported worse symptoms than those with no/mild GVHD in frequency, severity, and interference in normal activities. Several challenges were identified including poor access/literacy of electronic surveys, acute illness, and need for extensive research/resource support. We demonstrate the challenges yet potential of using PRO measures in acute GVHD. We demonstrate that the PROMIS-10 and PRO-CTCAE measures are able to capture several symptoms and QOL domains of acute GVHD. Further investigation into making PROs feasible in acute GVHD are needed.

Association between the choice of the conditioning regimen and outcomes of allogeneic hematopoietic cell transplantation for myelofibrosis.

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative treatment for myelofibrosis. However, the optimal conditioning regimen either with reduced-intensity conditioning (RIC) or myeloablative conditioning (MAC) is not well known. Using the Center for International Blood and Marrow Transplant Research database, we identified adults aged ≥18 years with myelofibrosis undergoing allo-HCT between 2008-2019 and analyzed the outcomes separately in the RIC and MAC cohorts based on the conditioning regimens used. Among 872 eligible patients, 493 underwent allo-HCT using RIC (fludarabine/ busulfan n=166, fludarabine/melphalan n=327) and 379 using MAC (fludarabine/busulfan n=247, busulfan/cyclophosphamide n=132). In multivariable analysis with RIC, fludarabine/melphalan was associated with inferior overall survival (hazard ratio [HR]=1.80; 95% confidenec interval [CI]: 1.15-2.81; P=0.009), higher early non-relapse mortality (HR=1.81; 95% CI: 1.12-2.91; P=0.01) and higher acute graft-versus-host disease (GvHD) (grade 2-4 HR=1.45; 95% CI: 1.03-2.03; P=0.03; grade 3-4 HR=2.21; 95%CI: 1.28-3.83; P=0.004) compared to fludarabine/busulfan. In the MAC setting, busulfan/cyclophosphamide was associated with a higher acute GvHD (grade 2-4 HR=2.33; 95% CI: 1.67-3.25; P<0.001; grade 3-4 HR=2.31; 95% CI: 1.52-3.52; P<0.001) and inferior GvHD-free relapse-free survival (GRFS) (HR=1.94; 95% CI: 1.49-2.53; P<0.001) as compared to fludarabine/busulfan. Hence, our study suggests that fludarabine/busulfan is associated with better outcomes in RIC (better overall survival, lower early non-relapse mortality, lower acute GvHD) and MAC (lower acute GvHD and better GRFS) in myelofibrosis.

Toxicity analysis of busulfan pharmacokinetic therapeutic dose monitoring.

Busulfan-based conditioning regimens are associated with serious toxicities and literature reports increased risk of toxicities when daily area under the curve concentrations exceed 6000 µM-minute. We implemented real time pharmacokinetic-guided therapeutic drug monitoring of busulfan for myeloablative conditioning regimens. The objective was to compare toxicity of intravenous busulfan before and after therapeutic drug monitoring implementation. The primary endpoint was incidence of hepatotoxicity. Medical records were retrospectively reviewed with weight-based dose Busulfan/Cyclophosphamide (BuCy) conditioning from August 2017 through March 2018 (N = 14) and therapeutic drug monitoring from April 2018 through December 2018 (N = 22). Recipients of busulfan therapeutic drug monitoring were younger than those receiving weight-based dose (median: 45 vs. 58 years, p = 0.008). No other baseline differences were observed. There was no difference in hepatotoxicity between therapeutic drug monitoring and weight-based dose (median 1 vs. 0 days, p = 0.40). In the therapeutic drug monitoring group, 45% of patients had increases and 41% had decreases in busulfan dose after Bu1. Repeat pharmacokinetic after Bu2 were required in 32% of patients. A pharmacokinetic dose monitoring program for myeloablative conditioning intravenous busulfan regimens may be considered a safe practice in stem cell transplant recipients. The majority of patients receiving pharmacokinetic-guided therapeutic drug monitoring required dose changes and therapeutic drug monitoring patients had no significant difference in toxicity compared to those receiving weight-based dose.

Relapse and Disease-Free Survival in Patients With Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation Using Older Matched Sibling Donors vs Younger Matched Unrelated Donors.

IMPORTANCE: Matched sibling donors (MSDs) are preferred for allogeneic hematopoietic cell transplantation (allo-HCT) in myelodysplastic syndrome even if they are older. However, whether older MSDs or younger human leukocyte antigen-matched unrelated donors (MUDs) are associated with better outcomes remains unclear. OBJECTIVE: To investigate whether allo-HCT for myelodysplastic syndrome using younger MUDs would be associated with improved disease-free survival and less relapse compared with older MSDs. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study assessed data reported to the Center for International Blood and Marrow Transplant Research database from 1761 adults 50 years or older with myelodysplastic syndrome who underwent allo-HCT using an older MSD or younger MUD between January 1, 2011, and December 31, 2017, with a median follow-up of 48 months. Data analysis was performed from January 8, 2019, to December 30, 2020. INTERVENTIONS/EXPOSURES: Allo-HCT from an older MSD (donor age ≥50 years) or a younger MUD (donor age ≤35 years). MAIN OUTCOMES AND MEASURES: The primary outcome was disease-free survival. Secondary outcomes were overall survival, relapse, nonrelapse mortality, acute graft-vs-host disease (GVHD), chronic GVHD, and GVHD-free relapse-free survival. RESULTS: Of 1761 patients (1162 [66%] male; median [range] age, 64.9 [50.2-77.6] years in the MSD cohort and 66.5 [50.4-80.9] years in MUD cohort), 646 underwent allo-HCT with an older MSD and 1115 with a younger MUD. In multivariable analysis, the rate of disease-free survival was significantly lower in allo-HCTs with older MSDs compared with younger MUDs (hazard ratio [HR], 1.17; 95% CI, 1.02-1.34; P = .02), whereas the difference in overall survival rate of allo-HCT with younger MUDs vs older MSDs was not statistically significant (HR, 1.13; 95% CI, 0.98-1.29; P = .07). Allo-HCT with older MSDs was associated with significantly higher relapse (HR, 1.62; 95% CI, 1.32-1.97; P < .001), lower nonrelapse mortality (HR, 0.76; 95% CI, 0.59-0.96; P = .02), lower acute GVHD (HR, 0.52; 95% CI, 0.42-0.65; P < .001), chronic GVHD (HR, 0.77; 95% CI, 0.64-0.92; P = .005), and a lower rate of GVHD-free relapse-free survival beyond 12 months after allo-HCT (HR, 1.42; 95% CI, 1.02-1.98; P = .04). CONCLUSIONS AND RELEVANCE: This cohort study found higher disease-free survival and lower relapse for allo-HCT in myelodysplastic syndrome using younger MUDs compared with older MSDs. The risk of nonrelapse mortality and GVHD was lower with older MSDs. These results suggest that the use of younger MUDs should be considered in the donor selection algorithm for myelodysplastic syndrome, in which it is pivotal to minimize relapse given limited treatment options for managing relapsed disease.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in T Cell Prolymphocytic Leukemia: A Contemporary Analysis from the Center for International Blood and Marrow Transplant Research.

T cell prolymphocytic leukemia (T-PLL) is a rare, aggressive malignancy with limited treatment options and poor long-term survival. Previous studies of allogeneic hematopoietic cell transplantation (alloHCT) for T-PLL are limited by small numbers, and descriptions of patient and transplantation characteristics and outcomes after alloHCT are sparse. In this study, we evaluated outcomes of alloHCT in patients with T-PLL and attempted to identify predictors of post-transplantation relapse and survival. We conducted an analysis of data using the Center for International Blood and Marrow Transplant Research database on 266 patients with T-PLL who underwent alloHCT between 2008 and 2018. The 4-year rates of overall survival (OS), disease-free survival (DFS), relapse, and treatment-related mortality (TRM) were 30.0% (95% confidence interval [CI], 23.8% to 36.5%), 25.7% (95% CI, 20% to 32%), 41.9% (95% CI, 35.5% to 48.4%), and 32.4% (95% CI, 26.4% to 38.6%), respectively. In multivariable analyses, 3 variables were associated with inferior OS: receipt of a myeloablative conditioning (MAC) regimen (hazard ratio [HR], 2.18; P < .0001), age >60 years (HR, 1.61; P = .0053), and suboptimal performance status, defined by Karnofsky Performance Status (KPS) <90 (HR, 1.53; P = .0073). Receipt of an MAC regimen also was associated with increased TRM (HR, 3.31; P < .0001), an elevated cumulative incidence of grade II-IV acute graft-versus-host disease (HR, 2.94; P = .0011), and inferior DFS (HR, 1.86; P = .0004). Conditioning intensity was not associated with relapse; however, stable disease/progression was correlated with increased risk of relapse (HR, 2.13; P = .0072). Both in vivo T cell depletion (TCD) as part of conditioning and KPS <90 were associated with worse TRM and inferior DFS. Receipt of total body irradiation had no significant effect on OS, DFS, or TRM. Our data show that reduced-intensity conditioning without in vivo TCD (ie, without antithymocyte globulin or alemtuzumab) before alloHCT was associated with long-term DFS in patients with T-PLL who were age ≤60 years or who had a KPS >90 or chemosensitive disease.

Comparison of Quality of Life and Outcomes between Haploidentical and Matched Related/Unrelated Donor Allogeneic Hematopoietic Cell Transplantation.

Haploidentical (haplo) donor grafts are a well-established alternative donor source for allogeneic hematopoietic cell transplantation (HCT); however, data comparing health-realted quality of life (HRQOL) measures between haplo-HCT and HCT using other donor sources are lacking. We hypothesized that post-transplantation HRQOL might not differ between haplo-HCT and HCT with other graft sources. We conducted a single-institution retrospective analysis comparing HRQOL of haplo-HCT with matched-related donor (MRD) HCT and matched unrelated donor (MUD) HCT for hematologic diseases. We included 90 haplo, 102 MRD, and 229 MUD adult first allogeneic HCTs performed between May 2014 and December 2019. HRQOL for haplo-HCT, MRD-HCT, and MUD-HCT were compared separately for myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC). HRQOL was assessed using the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) scale pretransplantation and at days +100 and +180 post-transplantation. MAC haplo-HCT showed no difference in all domains of HRQOL and other transplantation outcomes, including overall survival, compared with MAC MRD/MUD-HCT, except for a higher incidence of non-cytomegalovirus infections (P = .003). RIC haplo-HCT was associated with significantly better emotional well-being (P = .008) and functional well-being (P = .011) compared with MUD-HCT. RIC haplo-HCT was associated with higher rates of non-cytomegalovirus infections (P < .001) and relapse mortality (P = .044) but a lower rate of nonrelapse mortality (P = .008) compared with RIC MUD-HCT. Haplo-HCT had comparable total HRQOL scores and overall survival to MRD/MUD-HCT in both the MAC and RIC cohorts. Interrogation of HRQOL among disease-specific groups may further elucidate the existence of any additional benefits with these different transplantation modalities.

The impact of socioeconomic disparities on the use of upfront autologous stem cell transplantation for mantle cell lymphoma.

Using the National Cancer Database, we identified 10,290 patients with newly diagnosed mantle cell lymphoma (MCL) treated with chemotherapy with or without upfront autologous stem cell transplantation (ASCT). Only 17% of patients underwent ASCT. Patients who underwent ASCT were younger and more likely to have lower comorbidity scores, private insurance, higher income and education, and treatment received at an academic facility. On multivariable analysis, age, comorbidity index, insurance type, the transition of care, facility type, distance to facility, and diagnosis year were predictive for ASCT use. ASCT use was associated with improved 5-year overall survival in younger (82% vs. 64%, p < .001) and older (70% vs. 40%, p < .001) patients, which was retained in the matched propensity score and 12-month analyses. Female gender, the diagnosis year ≥2009, private insurance, higher income, and education were associated with superior survival, whereas Black race and higher comorbidities predicted inferior survival.

Influence of Killer Immunoglobulin-Like Receptors and Somatic Mutations on Transplant Outcomes in Acute Myeloid Leukemia.

Natural killer (NK) cells are regulated by killer immunoglobulin-like receptor (KIR) interactions with human leukocyte antigen class I ligands. Various models of NK cell alloreactivity have been associated with outcomes after allogeneic hematopoietic cell transplant (alloHCT), but results have varied widely. We hypothesized that somatic mutations in acute myeloid leukemia (AML) in the context of KIR profiles may further refine their association with transplant outcomes. In this single-center, retrospective, observational study, 81 AML patients who underwent matched-related donor alloHCT were included. Post-HCT outcomes were assessed based on mutational status and KIR profiles with the Kaplan-Meier method and log-rank test. On multivariable analysis those with any somatic mutations and C1/C2 heterozygosity had less acute graft-versus-host disease (GvHD) (hazard ratio [HR], 0.32; 95% confidence interval [CI], 0.14-0.75; P = .009), more relapse (HR, 3.02; 95% CI, 1.30-7.01; P = .010), inferior relapse-free survival (RFS; HR, 2.22; 95% CI, 1.17-4.20; P = .014), and overall survival (OS; HR, 2.21; 95% CI, 1.17-4.20; P = .015), whereas those with a missing KIR ligand had superior RFS (HR, 0.53; 95% CI, 0.30-0.94; P = .031). The presence of a somatic mutation and donor haplotype A was also associated with less acute GvHD (HR, 0.38; 95% CI, 0.16-0.92; P = .032), more relapse (HR, 2.72; 95% CI, 1.13-6.52; P = .025), inferior RFS (HR, 2.11; 95% CI, 1.07-4.14; P = .030), and OS (HR, 2.20; 95% CI, 1.11-4.38; P = .024). Enhanced NK cell alloreactivity from more KIR activating signals (donor B haplotype) and fewer inhibitory signals (recipient missing KIR ligand or C1 or C2 homozygosity) may help mitigate the adverse prognosis associated with some AML somatic mutations. These results may have implications for improving patient risk stratification prior to transplant and optimizing donor selection.

Fludarabine and Melphalan Compared with Reduced Doses of Busulfan and Fludarabine Improve Transplantation Outcomes in Older Patients with Myelodysplastic Syndromes.

Reduced-intensity conditioning (RIC) regimens developed to extend the use of allogeneic hematopoietic stem cell transplantation (HSCT) to older patients have resulted in encouraging outcomes. We aimed to compare the 2 most commonly used RIC regimens, i.v. fludarabine with busulfan (FluBu) and fludarabine with melphalan (FluMel), in patients with myelodysplastic syndrome (MDS). Through the Center for International Blood and Marrow Transplant Research (CIBMTR), we identified 1045 MDS patients age ≥60 years who underwent first HSCT with a matched related or matched (8/8) unrelated donor using an RIC regimen. The CIBMTR's definition of RIC was used: a regimen that incorporated an i.v. busulfan total dose ≤7.2 mg/kg or a low-dose melphalan total dose ≤150 mg/m2. The 2 groups, recipients of FluBu (n = 697) and recipients of FluMel (n = 448), were comparable in terms of disease- and transplantation-related characteristics except for the more frequent use of antithymocyte globulin or alemtuzumab in the FluBu group (39% versus 31%). The median age was 67 years in both groups. FluMel was associated with a reduced relapse incidence (RI) compared with FluBu, with a 1-year adjusted incidence of 26% versus 44% (P ≤ .0001). Transplantation-related mortality (TRM) was higher in the FluMel group (26% versus 16%; P ≤ .0001). Because the magnitude of improvement with FluMel in RI was greater than the improvement in TRM with FluBu, disease-free survival (DFS) was better at 1 year and beyond with FluMel compared with FluBu (48% versus 40% at 1 year [P = .02] and 35% versus 27% at 3 years [P = .01]). Overall survival was comparable in the 2 groups at 1 year (63% versus 61%; P = .4) but was significantly improved with FluMel compared with FluBu at 3 years (46% versus 39%; P = .03). Our results suggest that FluMel is associated with superior DFS compared with FluBu owing to reduced RI in older patients with MDS patients. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

A Phase II Trial of Imatinib Mesylate as Maintenance Therapy for Patients With Newly Diagnosed C-kit-positive Acute Myeloid Leukemia.

INTRODUCTION: Adults with acute myeloid leukemia (AML) have a high rate of remission; however, more than 50% relapse. C-kit is expressed in approximately 60% of patients with de novo AML and represents a potential therapeutic target. MATERIALS AND METHODS: Patients with newly diagnosed AML received 12 months of imatinib mesylate as maintenance therapy after the completion of post-remission therapy. The primary objective was to determine whether this approach improved progression-free survival (defined as no relapse and no death) compared with historical controls. RESULTS: The median progression-free survival of patients < 60 years of age was 52.1 months (historical control, 13 months) and for patients ≥ 60 years of age was 10.7 months (historical control, 8 months). The median level of AF1q expression was high (9.59), and 84% of patients had moderate or high levels of drug-resistance factors. CONCLUSIONS: Imatinib maintenance therapy may improve the outcome of newly diagnosed patients with AML who are < 60 years of age.

DNA methylation inhibition in myeloma: Experience from a phase 1b study of low-dose continuous azacitidine in combination with lenalidomide and low-dose dexamethasone in relapsed or refractory multiple myeloma.

The DNA methyltransferase inhibitor azacytidine (aza) may reactivate pathways associated with plasma cell differentiation, cell cycle control, apoptosis, and immune recognition and thereby restore sensitivity to lenalidomide (len) and dexamethasone (dex) in relapsed and/or refractory multiple myeloma (RRMM). We aimed to develop an aza regimen that reaches epigenetically active levels 8 times in 28 days with less bone marrow toxicity than the myeloid malignancy standard of 7 consecutive doses to enable safe combination with len. Aza was escalated from 30 mg/m2 once a week up to a predefined maximum of 50 mg/m2 twice a week in combination with GFR-adjusted len (≥ 60 mL/min: 25 mg, 3059 mL/min: 10 mg) day 1 to 21 every 28 days and dex 40 mg once a week followed by a limited expansion study to a total N of 23 at the highest tolerated dose. Fifty-one patients (pts) with RRMM were screened, 42 were treated and 41 were evaluable for response based on at least 1 response assessment or progression after treatment start. The median number of prior lines of therapy was 5 (1-11) and 81% (34) were refractory to len and/or pomalidomide (pom). Two DLTs occurred in different cohorts, 1 neutropenic fever in 1/6 pts on the aza 40 mg/m2 twice a week GFR ≥ 60 mL/min cohort and 1 GGT elevation in 1/6 pts on the aza 50 mg/m2 GFR 30-59 mL/min cohort. An MTD was not reached and aza 50 mg/m2 SC twice a week was chosen for the expansion study. At least possibly related Grade 3/4 AEs occurred in 28 pts (67%) with the following in > 1 pt: neutropenia (N = 16, 38%), anemia (N = 6, 14%), lymphopenia (N = 5, 12%), thrombocytopenia (N = 4, 10%), leukopenia (N = 4, 10%), febrile neutropenia (N = 4, 10%), fatigue (N = 3, 7%), fever (N = 2, 5%), and infection (N = 2, 5%). At a median follow up time for alive pts of 60.2 months (range: 36.1-82.5 months), the overall response rate (≥ partial response) and clinical benefit response rate (≥ minor response) was 22 and 32%, respectively, with 4 very good partial responses (10%), 5 partial responses (12%), and 4 minor responses (10%). The median PFS was 3.1 months (95% confidence interval [CI]: 2.1-5.1 months), median TTP 2.7 months (95% CI: 2.1-7.5 months), and median OS 18.6 months (95% CI: 12.9-33.0 months). Achieving at least minor response and reaching TTP > 6 months was associated with approximately 35% lower median plasma levels of the enzyme that inactivates aza, plasma cytidine deaminase (CDA, P< .0001). Two of the len refractory pts achieved longer disease control than with any prior regimen and 1 responded immediately after progression on len, bortezomib, and prednisone. Analyses of the methylation state of over 480,000 CpG sites in purified myeloma cells at screening were possible in 11 pts and on day 28 in 8 of them. As in other studies, the majority of differentially methylated CpGs compared to normal plasma cells were hypomethylated in myeloma. Treatment decreased the number of CpGs that were differentially methylated in normal plasma cells by > 0.5% in 6 and by > 5% in 3 of the 8 pts, most pronounced in 2 pts with clinically convincing aza contribution who achieved a reduction in overall differentially methylated CpGs by 23 and 68%, respectively, associated with increased expression of immunoglobulin genes. The study demonstrated tolerability of twice a week SC aza at 50 mg/m2 with len and dex in RRMM and suggested aza may help overcome the len/pom refractory state, possibly by activating differentiation pathways. Relatively low response rates and association of clinical benefit with low plasma levels of the aza inactivating enzyme CDA suggest the aza regimen will need to be optimized further and pt selection may be required to maximize benefit.

Survival following relapse after allogeneic hematopoietic cell transplantation for acute leukemia and myelodysplastic syndromes in the contemporary era.

OBJECTIVE/BACKGROUND: Relapse is the most common cause of treatment failure after allogeneic hematopoietic cell transplantation (alloHCT). No standard of care exists, and a wide range of treatments are used for post-alloHCT relapse. In the recent era, several novel therapies including targeted agents are available for acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS). METHODS: We reviewed outcomes after alloHCT relapse, with or without use of these newer agents for ALL, AML, and MDS. In total, 115 adults with relapsed or refractory ALL (n = 17), AML (n = 67), and MDS (n = 31) at median 5 (range, 1-64) months after their first alloHCT in 2010-2018 were included. RESULTS: Median follow-up was 19 (range, 6-80) months after relapse from alloHCT. Targeted agents were given to 29 (25%) patients. In multivariable analysis, use of targeted agent at any time point after relapse was not associated with survival. Matched unrelated (vs. matched sibling; hazard ratio [HR] 1.70; p = .027) or haploidentical donor grafts (vs. matched sibling; HR 2.69; p = .003), presence of grade II-IV acute graft-versus-host disease before relapse (HR 2.46; p < .001), and less than 12 months from HCT to relapse (<6 vs. > 12 months; HR 6.34; p < .001; 6-12 vs. > 12 months; HR 3.16; p = .005) were adverse prognostic factors for post-relapse survival. CONCLUSION: Outcomes after alloHCT relapse remain poor regardless of the novel agent use. Innovative treatment strategies are needed to improve outcomes after relapse post-alloHCT.