Reduced-intensity Hematopoietic Cell Transplantation Research Articles

Intensive Reinduction Chemotherapy Followed by Early Allogeneic Hematopoietic Cell Transplantation for Relapsed/Refractory High-Grade Myeloid Neoplasms

Outcomes for adults with relapsed/refractory (R/R) high-grade myeloid neoplasms remain poor, with allogeneic hematopoietic cell transplantation (HCT) the sole therapy likely to result in cure. We conducted the present study to determine the feasibility of early HCT-within 60 days of beginning reinduction chemotherapy-to see whether getting patients to HCT in an expeditious manner would expand the number of patients being offered this curative option. In this proof-of-principle feasibility study, we included adults age 18 to 75 years with R/R myeloid malignancies with ≥10% blood/marrow blasts at diagnosis who were eligible for a reduced-intensity HCT. Subjects received reinduction chemotherapy with cladribine, cytarabine, mitoxantrone, and filgrastim (CLAG-M) and proceeded to HCT with reduced-intensity conditioning (fludarabine/ melphalan). We enrolled 30 subjects, all of whom received CLAG-M reinduction, although only 9 underwent HCT within 60 days (<15, the predetermined threshold for feasibility "success"), with a median time to HCT of 48 days (range, 42 to 60 days). Eleven additional subjects received HCT beyond the target 60 days (off-study), with a median time to transplantation of 83 days (range, 53 to 367 days). Barriers to early HCT included infection, physician preference, lack of an HLA-matched donor, logistical delays, and disease progression, all of which may limit the real-world uptake of such early-to-transplantation protocols.

Patterns of Graft-Versus-Host Disease (GvHD) Prevention and Management in the Eastern Mediterranean (EM) Region: A Worldwide Network for Blood & Marrow Transplantation (WBMT) Survey

Introduction: GvHD is a significant cause of morbidity and mortality in recipients of allogeneic hematopoietic cell transplant (HCT). The prevention, management, and treatment of GvHD vary in different regions worldwide. This WBMT study aims to better understand the current clinical practices of GvHD prevention and management around the globe. This study presents our survey results in the Eastern Mediterranean Region. Methodology: This is a cross-sectional survey-based study involving hematopoietic cell transplant (HCT) centers in the EM region. Participants of the survey were programs' directors or their designees. The survey comprised two parts; the first part aimed to study the practices of GvHD prevention, whereas the second part aimed to study GvHD management and treatment. The survey was distributed and filled out between December 2022 and May 2023. Results: Thirty participants from 28 institutions responded. Participants were from eleven different countries in the EM region. Fourteen participants (50%) filled it for combined pediatrics and adult HCT programs. The remaining participants filled it for programs performing HCT, either only in adult (27%) or pediatrics (23%) patients. The majority of participants indicated that cyclosporine and methotrexate combination is the most used GvHD prophylaxis therapy in both myeloablative and reduced intensity HCT in their centers. Cyclosporine was the predominantly used calcineurin inhibitor (CNI), followed by tacrolimus. All centers using cyclosporine indicated that they monitor its level, with 200-300 mcg/L being the target in 66% of the survey. Cyclosporine was typically given for 2-12 months after HCT, with around 80% of centers stopping it at 3-4 months post-HCT in recipients with malignant indications and around 90% of centers stopping it around 6-12 months post-HCT in recipients with non-malignant indications. When tacrolimus is used, results showed that it is typically used for similar duration to cyclosporine. Twenty-nine participants reported using post-transplant cyclophosphamide (PTCy) in their centers, with seven centers (24%) reporting its use in indications other than haploidentical transplants. Additionally, the results show that PTCy is typically used in combination with other medications, with 53% of participants reporting that it is used along with mycophenolate mofetil and cyclosporine and only one participant reported its use as a single agent. Seven participants (23%) reported that PTCy is typically used in doses less than 50 mg/kg. In patients with established GvHD, steroids were most commonly used alone as a first-line therapy in acute and chronic GvHD. The majority of centers report re-introducing or continuing the immunosuppressive agent used in GvHD prevention, with few centers indicating that they switched to another CNI. 64% and 55% of centers indicated that they have a standard-operating procedure (SOP) for steroid-refractory acute GvHD (aGvHD) and chronic GvHD (cGvHD), respectively. Only two centers reported involving steroid-refractory GvHD patients in clinical trials. Second-line therapy for steroid-refractory aGvHD and cGvHD varies significantly between centers depending on the type of GvHD and organ involved. In steroid-refractory aGvHD, ruxolitinib was the most frequently listed agent to be considered in the second line, regardless of the involved organ. Ruxolitinib was followed by Extracorporeal photopheresis in Skin aGvHD, Budesonide in lower GI tract aGVHD, and Mycophenolate Mofetil in liver aGvHD. In cGvHD, ruxolitinib was also the most frequently listed medication. However, more significant variability between centers was noted in treating organ-specific cGvHD. Conclusion: GvHD prevention and management practices vary between the different EM region centers. Some variations could be related to access to some medications. This might indicate the need for more evidence-based practices in preventing and managing GvHD and possibly adjusting the guidelines according to access and availability of some medications. WBMT is currently working on understanding the global patterns of GvHD practices in other regions and, ultimately, a global comparative study of all data combined.

Health-Related Quality of Life in a Biologic Assignment Trial of Reduced Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients Aged 50-75 with Advanced Myelodysplastic Syndrome

Health-Related Quality of Life in a Biologic Assignment Trial of Reduced Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients Aged 50-75 with Advanced Myelodysplastic Syndrome

Reduced Intensity Hematopoietic Cell Transplantation Improves Cerebral Hemodynamics in Children with Sickle Cell Disease

IntroductionAllogeneic hematopoietic cell transplantation (HCT) is increasingly being utilized in patients with sickle cell disease (SCD) to prevent progressive organ dysfunction, including for primary or secondary stroke prevention. However, outcomes after HCT have mostly been evaluated using broad measures such as overall survival and event free survival with limited direct physiologic evidence of improved cerebral hemodynamics. Cerebral blood flow (CBF; mL blood/100 g tissue/min) is increased in SCD to compensate for chronic anemia, reduced oxygen carrying capacity and to maintain adequate oxygen delivery to the brain tissue. In SCD patients, CBF is inversely associated with intelligence quotient (Strouse JJ, et al. Blood. 2006;108(1):379-381.) and working memory (Prussien KV, et al. Stroke. 2021;52(5):1830-1834.) and has been shown to improve with blood transfusions (Guilliams KP, et al. Blood. 2018;131(9):1012-1021.). Assessment of CBF may help predict long-term neurocognitive outcomes in patients with SCD and assess therapeutic responses to therapies. Additionally, the high metabolic demand of the brain potentially makes assessment of CBF a sensitive predictor of future multiorgan damage in patients with SCD and hence may be useful to help determine eligibility of patients for curative therapies.MethodsWe performed anatomical and hemodynamic magnetic resonance imaging (MRI) of the brain prior to, and at 6 months after HCT in children with SCD undergoing a reduced intensity conditioning based HCT on a clinical study (NCT04362293). All patients received pretransplant conditioning with hydroxyurea, azathioprine, alemtuzumab, thiotepa and low dose total body irradiation (200-400 cGy). All patients received an unmanipulated mobilized peripheral blood derived hematopoietic stem and progenitor cell graft. One patient who received the graft from a haploidentical (HAPLO) donor also received post-transplant cyclophosphamide. Graft versus host disease prophylaxis comprised of sirolimus. A 3-dimensional (3D) T1 sequence was used for gray/white matter segmentation. 3D-pulsed arterial spin labeling (ASL) perfusion imaging (3 mm isotropic) was acquired to measure resting CBF. Mean CBF values were calculated from gray matter. Mean ± standard deviation and median values for various variables are presented.ResultsFour consecutive patients had 2 serial MRIs performed (one before HCT and another 6 months after HCT). Median age at HCT was 14.5 years. Indications for HCT, donor type and whether patients were receiving chronic transfusion therapy (CTT) prior to HCT are indicated in the Table. No patient had prior evidence of overt stroke. All patients engrafted and had >99% donor myeloid chimerism at the time of the post-HCT imaging. Mean pre-HCT hemoglobin was 8.7 ± 0.8 g/dL (median 8.6 g/dL) and it increased to 12.5 ± 2.1 g/dL (median 12.4 g/dL) at 6 months after HCT. All patients exhibited elevated resting CBF values prior to HCT (123.8 ± 32.2 mL blood/100 g tissue/min, median 112.8 mL blood/100 g tissue/min), that decreased following HCT (71.1 ± 32.1 mL blood/100 g tissue/min, median 72.8 mL blood/100 g tissue/min) (Table and Figure). None of the patients had any clinical neurological complications or imaging evidence of new infarcts or anatomical abnormalities in the follow up period.ConclusionOur preliminary results indicate that it is feasible to quantify CBF in patients with SCD before and after HCT using MRI. We demonstrate that cerebral hemodynamics improve after HCT in children with SCD, indicated by a decrease in CBF to near normal values (normal CBF ~80 mL blood/100 g tissue/min). The more substantial changes (-50% and -78%) are seen in children who were not receiving CTT, suggesting that CTT might partially mitigate CBF elevation prior to HCT. Nevertheless, 2 patients receiving CTT prior to HCT also had a further modest decrease in CBF after HCT (-5% and -18%). We plan to follow these changes at serial time points annually after HCT and correlate them with changes in neurocognitive functioning and other functional MRI measures. Improved CBF is expected to reduce stroke risk and may also preserve or improve neurocognitive functioning, and prospective monitoring of these outcomes are underway.Data on all the study participants who have undergone an HCT and had 2 serial MRIs performed by the ASH annual meeting will be presented. [Display omitted] DisclosuresSharma: Vertex Pharmaceuticals/CRISPR Therapeutics: Other: Salary support paid to institution; Medexus Inc: Consultancy; CRISPR Therapeutics: Other, Research Funding; Novartis: Other: Salary support paid to institution; Spotlight Therapeutics: Consultancy; Vindico Medical Education: Honoraria. Triplett: Miltenyi: Other: Travel, meeting registration. Hankins: Vindico Medical Education: Consultancy; UpToDate: Consultancy; Global Blood Therapeutics: Consultancy; Bluebird Bio: Consultancy.

Myeloablative Hematopoietic Cell Transplantation (HCT) for Low and Intermediate Disease Risk Index Myeloid Malignancies Results in Better Outcomes Compared to Reduced Intensity HCT

The optimal regimen intensity before allogeneic hematopoietic cell transplantation (HCT) remains an unsettled question. The recent Blood and Marrow Transplant Clinical Trial Network BMTCTN 0901 randomized phase III study showed that Myeloablative conditioning (MA) results in better relapse-free survival and a trend towards better overall survival compared to reduced intensity conditioning (RIC). The findings of BMTCTN 0901 though contradicts several prior studies addressing the same question, was limited by the fact that most patients in the RIC received fludarabine/low dose Busulfan and the study was not designed to assess the effect of intensity on patients with different disease risk index (DRI) groups. Acute myeloid leukemia and myelodysplastic syndrome patients with low/intermediate DRI tend to respond well to chemotherapy and can potentially be cured with chemotherapy regimens alone. On the other hand, high and very high risk DRI myeloid malignancies have a high relapse rate and very low rates of success with chemotherapy only approach. We hypothesize that conditioning intensity benefit is limited to patients with low/intermediate risk DRI and no such benefit is seen in the high/very high risk DRI myeloid malignancy patients. To answer this question, we retrospectively analyzed AML/MDS HCT recipients with low/intermediate DRI to assess the impact of conditioning intensity on overall survival (OS), disease free survival (DFS), relapse, and non-relapse mortality (NRM). Survival was calculated using the Kaplan-Meier estimator. Univariate analysis with Gray test and log-rank test will be used for cumulative incidence and survival respectively. Cox regression models were built to study the effect of conditioning intensity adjusted for other significant factors on OS, NRM, DFS, relapse and graft-versus-host disease (GVHD). Conditioning intensity was retained in the cox models and other variables were selected to be included if the P-value was less than 0.05.A total of 232 consecutive allogeneic HCT recipients with low/intermediate DRI myeloid malignancy (AML 170, MDS 60) were included in the analysis with a median follow up of 37 months. Median age was 55 years (18, 75) and 83% were of white race. Patient and transplant related characteristics were as follows: 42% RIC, 11% Myeloablative high dose TBI, 47% non-TBI Myeloablative conditioning; 21% bone marrow graft; 31% matched related donor transplant MRDT, 47% matched unrelated donor transplant MUDT, 22% haploidentical donor HIDT; 49% had hematopoietic cell transplant comorbidity index HCT-CI ≥3 ; donor/recipient female to male 21%; and donor/recipient CMV +/+ 42%, -/- 19%, other 39%. Both MA and RIC groups had similar patient, disease and transplant related characteristics except for a higher percentage of MA recipients received methotrexate as part of their GVHD prophylaxis compared to RIC (78% vs 55%, p<0.001). Recipients of Myeloablative conditioning had better overall survival estimate (3-year 69% vs 57%, p=0.001), DFS (3-year 65% vs 51%, p=0.003) and lower relapse cumulative incidence (3-year 17% vs 32%, p=0.01) but similar NRM (3-year 19% vs 17%, p=0.04) to RIC recipients (figure 1). There was no difference in the cumulative incidence of grade 2-4 acute and moderate-severe GVHD between Myeloablative and RIC groups. Multivariate analysis revealed MA conditioning to be associated with better DFS (HR 0.58, 95% CI 0.39-0.88, p=0.01), lower relapse (HR 0.56, 95% CI 0.32-0.97, p=0.038) and similar NRM (HR1.11, 95% CI 0.54-2.26, p=0.781) compared to RIC. When same analysis was performed for high/very high DRI myeloid malignancy patients (N=247), conditioning intensity had no effect on OS, DFS, Relapse and NRM (P value>0.10 for all).Myeloablative conditioning results in better overall survival and disease control when compared to RIC among AML/MDS patients with low/intermediate DRI risk group. This benefit is not shown among high/very high DRI risk patients. [Display omitted] DisclosuresSolh:Celgene: Speakers Bureau; ADC Therapeutics: Research Funding; Amgen: Speakers Bureau.

Transfusion burden following reduced intensity allogeneic hematopoietic cell transplantation: Impact of donor type.

Transfusions are essential for allogeneic hematopoietic cell transplant (HCT), yet they are influenced by graft, donor, and other factors. We analyzed transfusions in 165 adult reduced intensity HCTs (2016-2019): HLA matched sibling donor (MSD) (n=59), matched URD (n=25), UCB (n=33), and haploidentical (haplo, n=48) detailing the cumulative incidence of platelet and RBC transfusion independence, total transfusions (day-10 to day+100) plus transfusion densities (per week) over 110 days. Platelet recovery to 20× 109 /L by 6months occurred in 39/48 (81.25%) haplo recipients (median 33 [range, 0-139]) days vs. 58/59 (98.3%) MSD (median 10 [0-37]), 21/25 (84%) matched URD (median 20 [0-153]), and 29/33 (87.87%) UCB (median 48 [29-166]) days, p< .01. Regression analysis demonstrated a lower likelihood of prompt platelet recovery in matched URD, UCB, or haplo HCTs vs. MSD. Recovery to platelet independence was quickest in MSD (median 8 days [range 0-94]), vs. URD (median 16 days [0-99]), UCB (median 57 [0-94]), or haplo (median 45 [12-97]) days, p< .01. Platelet needs were unaffected by age, conditioning, or acute GVHD. RBC transfusion independence was achieved in 78% of MSD, 64% URD, and 82% UCB, though less frequent (58%) and slowest in haplo recipients, p< .01. All haplo and UCB recipients required platelet transfusions vs. only 51% of MSD and 76% of URD. RBC needs were highest in UCB and haplo HCTs. The transplant donor influences the transfusion burden with greater platelet and RBC needs in haplo and UCB HCT which directly contributes to increased cost of care.

Hematopoietic cell transplantation and cellular therapy survey of the EBMT: monitoring of activities and trends over 30 years

Numbers of Hematopoietic cell transplantation (HCT) in Europe and collaborating countries continues to rise with 48,512 HCT in 43,581 patients, comprising of 19,798 (41%) allogeneic and 28,714 (59%) autologous, reported by 700 centers in 51 countries during 2019. Main indications were myeloid malignancies 10,764 (25%), lymphoid malignancies 27,895 (64%), and nonmalignant disorders 3173 (7%). A marked growth in CAR-T cellular therapies from 151 in 2017 to 1134 patients in 2019 is observed. This year’s analyses focus on changes over 30 years. Since the first survey in 1990 where 143 centers reported 4234 HCT, the number has increased to 700 centers and 48,512 HCT. Transplants were reported in 20 countries in 1990, and 51, 30 years later. More than 800,000 HCT in 715,000 patients were reported overall. Next to the massive expansion of HCT technology, most notable developments include the success of unrelated donor and haploidentical HCT, an increase followed by decrease in the number of cord blood transplants, use of reduced intensity HCT in older patients, and the phenomenal rise in cellular therapy. This annual report of the European Society for Blood and Marrow Transplantation (EBMT) reflects current activity and highlights important trends vital for health care planning.

Conditioning regimen intensity and low-dose azacitidine maintenance after allogeneic hematopoietic cell transplantation for acute myeloid leukemia

Azacitidine (AZA) maintenance following allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) may reduce relapse risk and improve survival. Given logistic and toxicity-related challenges, identifying subgroups appropriate for this approach is an unmet need. Using data from two centers, we retrospectively compared event-free survival (EFS) and overall survival (OS) of AML and MDS patients who received AZA maintenance (n = 59) with historic controls (n = 90). Controls were selected according to the following criteria: no death, relapse, or Grade III–IV acute GVHD for 100 days after transplant. In multivariable analysis, AZA maintenance yielded significantly improved EFS (p = 0.019) and OS (p = 0.011). Outcomes differed according to regimen intensity. For reduced-intensity transplant, EFS (p = 0.004) and OS (p = 0.004) were significantly improved and equivalent to myeloablative transplant. A significant benefit following myeloablative transplant was not observed. Within the limitation of its retrospective nature, this study suggests that AZA maintenance improves outcomes following reduced-intensity HCT, comparable to myeloablative HCT.

Myeloablative versus Reduced-Intensity Hematopoietic Cell Transplantation in Myelodysplastic Syndromes: Systematic Review and Meta-analysis.

In a systematic review and meta-analysis, we compared allogeneic transplant outcomes after myeloablative conditioning (MAC) versus reduced-intensity conditioning (RIC) in patients with myelodysplastic syndromes. Only 2 published randomized clinical trials were found, with a pooled sample size of 183 (RIC, 92; MAC, 91). Both studies suggested an overall survival advantage after RIC, with a pooled hazard ratio (HR) of .67 (95% confidence interval [CI], .41 to 1.09) for RIC versus MAC. Relapse results were also concordant, with a pooled HR of 1.55 (95% CI, .74 to 3.25) for RIC versus MAC. Neither result was statistically significant. Comparisons for other outcomes were unremarkable. In conclusion, the evidence for the optimal conditioning intensity in myelodysplastic syndromes is weak. Post-transplant maintenance strategies and incorporation of genomic information into decision-making may improve post-transplant outcomes.

Yttrium-90-labeled anti-CD45 antibody followed by a reduced-intensity hematopoietic cell transplantation for patients with relapsed/refractory leukemia or myelodysplasia.

Outcomes of patients with persistent high-risk leukemia or myelodysplasia prior to allogeneic hematopoietic cell transplantation are dismal. We therefore conducted a phase I trial evaluating the use of CD45-targeted radiotherapy preceding hematopoietic cell transplantation with the goal of improving outcomes for this high-risk scenario. Fifteen patients, median age 62 (range 37-76) years, were treated: ten with advanced acute myeloid leukemia, five with high-risk myelodysplastic syndrome. All patients had evidence of disease prior to treatment including nine with marrow blast counts ranging from 7-84% and six with minimal residual disease. Patients received escalating doses of yttrium-90-labeled anti-CD45 antibody followed by fludarabine and 2 Gy total body irradiation prior to human leukocyte antigen-matched, related or unrelated hematopoietic cell transplantation. Although a maximum dose of 30 Gy was delivered to the liver, no dose-limiting toxicity was observed. Therefore, the maximum-tolerated dose could not be estimated. Treatment led to complete remission in 13 patients (87%). All patients engrafted by day 28. Six patients relapsed, median of 59 (range 6-351) days, after transplantation. The 1-year estimate of relapse was 41%. Eight patients (53%) are surviving with median follow up of 1.8 (range 0.9-5.9) years. Estimated overall survival at one and two years was 66% and 46%, respectively, with progression-free survival estimated to be 46% at each time point. In conclusion, the combination of 90Y-DOTA-BC8 with an allogeneic hematopoietic cell transplantation regimen was feasible and tolerable. This approach appears promising in this high-risk leukemia/myelodysplasia patient population with active disease. (Trial registered at clinicaltrials.gov identifier: NCT01300572.)

It's Not All in the Conditioning or the Perils of Early Trial Cessation

It's Not All in the Conditioning or the Perils of Early Trial Cessation

Effect of donor type in patients with AML or MDS undergoing reduced intensity hematopoietic cell transplant.

7059Background: Haploidentical (haplo) hematopoietic cell transplants (HCT) are a promising option for patients. Overall survival (OS) is comparable in patients receiving haplo vs matched unrelated...

Cognitive Functioning After Hematopoietic Cell Transplantation for Hematologic Malignancy: Results From a Prospective Longitudinal Study.

Purpose Cognitive impairment is well-recognized after myeloablative allogeneic hematopoietic cell transplantation (HCT). However, cognitive functioning after reduced-intensity allogeneic or autologous HCT remains unclear. Methods A total of 477 HCT recipients (236 autologous, 128 reduced-intensity allogeneic, 113 myeloablative allogeneic) underwent standardized neuropsychologic testing before HCT and at 6 months and 1, 2, and 3 years after HCT. Ninety-nine frequency-matched healthy controls underwent testing at commensurate time points. Primary outcomes of the study were practice effect-adjusted domain-specific T scores and global deficit scores. Piecewise generalized estimating equation models were used to compare groups and to identify associated variables and post-HCT trends of cognitive impairment. Results Median age was 52 years (range, 18 to 74 years) for HCT recipients and 55 years (range, 19 to 73 years) for controls. Post-HCT scores were comparable between controls and autologous and reduced-intensity HCT recipients. Myeloablative HCT recipients had significantly lower ( P < .001) post-HCT scores than controls for executive function, verbal speed, processing speed, auditory memory, and fine motor dexterity. Pre-HCT to 6 months post-HCT scores did not change after reduced-intensity HCT but declined significantly for fine motor dexterity ( P < .001) after myeloablative HCT. However, pre-HCT to 3 years post-HCT scores declined significantly ( P < .003) in reduced-intensity HCT recipients for executive function, verbal fluency, and working memory. Older age, male sex, and lower education, income, and cognitive reserve were associated with post-HCT cognitive impairment. At 3 years post-HCT, global cognitive impairment was present in 18.7% of autologous and 35.7% of allogeneic HCT recipients. Conclusion Myeloablative allogeneic HCT recipients showed significant cognitive decline compared with healthy controls. Reduced-intensity allogeneic HCT recipients showed evidence of delayed decline. Cognitive functioning in autologous HCT recipients generally was spared. The study identified vulnerable subpopulations that could benefit from targeted interventions.

Development and Scale-up of a Novel GMP Method for Enrichment and Expansion of Terminally Differentiated Adaptive Natural Killer Cells (FATE-NK100) with Enhanced Anti-Tumor Function

Natural killer (NK) cells are innate lymphoid cells that mediate immune responses against pathogens and cancer. Human NK cells are distinguished by the surface phenotype CD3-CD56+ and differential expression of the CD56 surface antigen defines subsets. CD56bright NK cells are presumed to be precursors of CD56dim NK cells, and terminal maturation of CD56dim NK cells is associated with acquisition of CD57. Rather than being an immunosenescence marker CD57 acquisition represents a shift toward greater effector function, including increased CD16 signaling (Fc receptor responsible for triggering antibody-dependent cellular cytotoxicity), enhanced cytotoxicity and decreased responsiveness to interleukin (IL)-12 and IL-18 stimulation. Cytomegalovirus (CMV) infection is uniquely associated with expansion of CD57+ NK cells expressing the activating receptor NKG2C.We have reported that in vivo expanded of CD57+NKG2C+ NK cells (referred to as adaptive NK cells) persist for over one year and are directly associated with reduced leukemia relapse after reduced intensity hematopoietic cell transplantation. Ex vivo expansion to enrich the subset of cells with the adaptive NK cell phenotype represents a new strategy to obtain high numbers of NK cells with enhanced effector function for use in adoptive transfer to treat cancer patients. The main challenge in enriching for CD57+ NK cells using current ex vivo expansion protocols is that IL-15, the cytokine that drives NK cell proliferation and is critical for NK cell survival preferentially expands less mature NK subsets that fail to terminally differentiate in culture. Our group has developed a novel NK cell expansion method that overcomes this barrier. Peripheral blood mononuclear cells from CMV seropositive donors are depleted of CD3+ T cells and CD19+ B cells and cultured for 7-9 days with IL-15 and a small molecule inhibitor of glycogen synthase kinase 3-beta (GSK3β), a multifunctional kinase downstream of the PI(3)K pathway. Compared to vehicle control, addition of the GSK3β inhibitor led to a substantial increase (2.2-fold ± 0.19, n=23, p<0.0001) in the CD57+ NK cell population. NK cells were highly enriched (90.9% ± 2.2) relative to the pre-cultured population post CD3/CD19 depletion (23.3% ± 2.5) (p<0.0001) Sorting experiments where purified NK cell subsets were cultured with monocytes obtained from the same donor and either vehicle or GSK3β inhibitor clearly demonstrated that the GSK3β inhibitor enhanced NK cell maturation. Importantly, NK cells expanded in the presence of the GSK3β inhibitor exhibited enhanced interferon (IFN)-γ production relative to the vehicle control in response to leukemia cells in vitro (2.15-fold ± 0.60, n=7, p=0.0002)and were superior in their ability to control tumor growth out to at least one month in a xenogeneic adoptive transfer model. To determine whether inhibition of GSK3β acted directly or indirectly on NK cells to drive terminal differentiation, purified CD56+ NK cells were cultured with or without monocytes in the presence or absence of the GSK3β inhibitor.The presence of differentiated monocytes was required for effective terminal NK cell differentiation, suggesting a monocyte-dependent, indirect effect of GSK3β (Figure 1A). Monocytes cultured with the GSK3β inhibitor exhibited markedly higher surface expression of an array of markers associated with monocyte maturation including HLA-DR, IL-15Rα, CD80, CD83 and CCR7 (Figure 1B). Thus, our data demonstrate that efficient NK cell differentiation is dependent upon the maturation state of the co-cultured monocytes.We have scaled our process to manufacture a GMP product (referred to as FATE-NK100) for clinical use. Using a representative apheresis product from a CMV seropositive donor containing 19.8 x 108 CD57+ NK cells and 1.7 x 108 CD57+NKG2C+ adaptive NK cells, we achieved 6.4-fold NK cell expansion resulting in a final GMP-grade product containing 142.2 x 108 CD57+ NK cells and 15.8 x 108 CD57+NKG2C+ adaptive NK cells.The cytotoxicity of activity of these ex vivo expanded adaptive NK cells in response to tumor targets is superior that of CD3/CD19-depleted haploidentical NK cells activated overnight with either IL-2 or IL-15 in the NK products in current clinical trials.These data have been presented to the FDA in preparation for a clinical trial of FATE-NK100 in lymphodepleted patients with advanced AML anticipated for Q1 2017. [Display omitted] DisclosuresCichocki:Fate Therapeutics, Inc: Research Funding. Valamehr:Fate Therapeutics, Inc: Employment. Cooley:Fate Therapeutics: Research Funding. Bjordahl:Fate Therapeutics, Inc: Employment. Rezner:Fate Therapeutics, Inc: Employment, Equity Ownership. Rogers:Fate Therapeutics, Inc: Employment. Green:Fate Therapeutics, Inc: Employment. McKenna:Fate Therapeutics, Inc: Research Funding. Shoemaker:Fate Therapeutics: Employment, Equity Ownership. Wolchko:Fate Therapeutics: Employment. Miller:Fate Therapeutics: Consultancy, Research Funding; Oxis Biotech: Consultancy, Other: SAB.

Reduced Intensity Hematopoietic Cell Transplantation in Active Disease AML Is Associated with Leukemia Free Survival and Relapse Comparable to Myeloablative Conditioning

Introduction: Up to 40% of new acute myeloid leukemia (AML) patients fail to achieve complete remission (CR), and a significant number of patients achieving remission eventually relapse. Allogeneic hematopoietic cell transplantation (allo-HCT) remains the best curative option for these patients with a long-term leukemia free survival (LFS) of around 20-30% with the use of intensive myeloablative condition (MAC) transplants. Active disease AML patients otherwise deemed unfit for MAC regimens have limited treatment options. Although reduced intensity condition (RIC) has broadened transplant eligibility in the elderly AML patients particularly in CR, there is a paucity of data on the use RIC allo-HCT in AML patients with active disease. To answer this question, we retrospectively analyzed data from active disease AML patients who underwent RIC allo-HCT and compared their outcomes with contemporaneous patients who underwent MAC allo-HCT at our institution.Patients and methods: Our cohort included all patients with active disease AML (primary induction failure, relapsed refractory or cytogenetic persistence) at the time of transplantation, who underwent allo-HCT at Washington University Medical Center in St. Louis between January 2006 and June 2015. Patients were classified according to the intensity of conditioning regimens: MAC versus RIC. The primary study endpoints were leukemia free survival (LFS) and overall survival (OS). LFS was defined as the time from the achievement of CR after allo-HCT to the time of relapse, death in remission, or last follow-up. OS was defined as the time from transplantation to the time of death from any cause or last follow-up. The between-group differences in LFS and OS were described using Kaplan-Meier (KM) survival curves and compared by log-rank test. Univariate Cox regression analysis for LFS was performed. All analyses were two-sided, and significance was set at a p-value of 0.05, using SAS 9.4 (SAS Institutes, Cary, NC).Results: 138 patients were included. 30 patients (21.7%) underwent RIC allo-HCT and 108 (78.3%) underwent MAC allo-HCT. Their baseline characteristics are listed in Table 1. 21 patients (72.4%) in RIC and 77 (81.9%) in MAC achieved CR on day-28 bone marrow biopsy. Notably, there were 16 patients (1 RIC and 15 MAC) who died prematurely without post-transplant evaluation; subsequently they were excluded from LFS, relapse and NRM calculations. There was no difference in the LFS in these two groups; 1-year and 3-year LFS were 40.6% (95% CI 23-70) and 33.1% (95% CI 17-66) in the RIC patients while 40.7% (95% CI 31-54) and 33.2% (95% CI 23-47) in the MAC patients, respectively (p=0.99) (Figure 1A). Similarly the CI of relapse at 1 year and 3 year was not different in the two groups; 45.8% (95% CI 30-71) and 50.5% (95% CI 33-76) in RIC group vs. 51.9% (95% CI 43-63) and 56.8% (95% CI 48-67) in MAC group, respectively (p=0.61) (Figure 1B).The CI of NRM at 1-year and 3-year was 28.1% (95% CI 16-50) and 32.6% (95% CI 19-56) in RIC group compared to 17.9% (95% CI 11-28) and 21.0% (95% CI 14-31) in the MAC group (p = 0.21). However, OS in both groups remained poor with 1-year and 3-year OS of 25.1% (95% CI 14-44) and 13.2% (95% CI 6-31) in RIC vs. 35.5% (95% CI 28-46) and 22.0% (95% CI 15-32) in MAC, respectively (p = 0.21). On univariate analysis for LFS and relapse, only cGvHD was associated with higher LFS (p<0.01, HR 0.27, 95% HR 0.13-0.52) and lower relapse risk (p= 0.01, HR 0.37, 95% HR 0.15-0.89) in these patients. On multivariate analysis for LFS, only cGvHD was statistically significant (p<0.01, HR 0.32, 95% HR 0.18-0.56). On the other hand, intermediate cytogenetic risk (p=0.01, HR 1.59, 95% HR 1.08-2.34) and cGvHD (p<0.01, HR 0.12, 95% HR 0.05-0.27) were significant for OS.Conclusion: The use of RIC allo-HCT in active disease AML is associated with LFS and relapse comparable to MAC allo-HCT. However, high relapse rates and NRM, in both groups translated into poor long term OS. Careful selection of patients and early utilization of transplant without subjecting these patients to multiple salvage regimens might help lower NRM rates in future studies. Notably, our study might open a window for future prospective studies aimed at finding improved ways to harness the graft versus leukemia (GvL) effect associated with RIC transplantation in patients who are otherwise not able to tolerate more toxic intensive conditioning regimens. [Display omitted] [Display omitted] [Display omitted] DisclosuresDiPersio:Incyte Corporation: Research Funding. Vij:Karyopharm: Honoraria; Janssen: Honoraria; Bristol-Myers Squibb: Honoraria; Novartis: Honoraria; Amgen: Honoraria, Research Funding; Celgene: Consultancy; Takeda: Honoraria, Research Funding.

Exploring the Potential of JAK1/2 Inhibitor Ruxolitinib with Reduced Intensity Hematopoietic Cell Transplantation (HCT) for Myelofibrosis: Stage I Results of a Prospective Trial Conducted through the Myeloproliferative Disorders - Research Consortium (MPD-RC)

We conducted a two-stage Simon phase II, multi-center study in two groups: related and unrelated donor transplants. Based on the results of a previously conducted prospective study (MPD-RC 101, Rondelli et al, Blood, 2014) demonstrating relatively poor outcome in the unrelated donor arm due to high non-relapse mortality and graft failure (GF), we sought to improve this noted disparate outcome. The hypothesis driving this trial was that pre-transplant JAK1/2 inhibition would result in an increase in performance status, reduction in splenomegaly and inflammatory cytokine expression leading to improved HCT outcome. In the unrelated arm in the first 11 patients, the trial was to be terminated if 6 or more failures (GF or death due to any cause by 100 days post-transplant) were observed. In the related arm in the first 11 patients, the trial was to be terminated if 3 or more failures were observed.Key eligibility criteria included diagnosis of primary MF or post-PV MF or post-ET MF, age 18-70 years, and DIPSS int-2/high risk disease or int-1 risk disease with at least one additional risk factor. Patients could have received up to 6 months of ruxolitinib prior to enrollment provided that there was no evidence of loss of response to ruxolitinib during this period.Ruxolitinib was given for 56 days followed by a 4-day taper ending day -6. The conditioning regimen utilized was IV fludarabine 40 mg/m2 IV and IV busulfan 2.0 mg/KBW IV once daily for 4 days from days -5 to -2. GVHD prophylaxis consisted of cyclosporine or tacrolimus and methotrexate. Patients undergoing unrelated donor HCT also received low dose thymoglobulin (0.5 mg/KBW on day -3/2.0 mg/KBW on day -2 & day -1).The study has enrolled 21 patients (related, 7; unrelated, 14) with a median age of 59 years (range 39-70). 17 (81%) patients had palpable splenomegaly with median spleen size of 11 cm, and 16 patients had int-2/high risk disease. Of the 21 patients, 19 patients received transplantation (related 5/7 [71%], unrelated 14/14 [100%] underwent transplant). Two patients in the related arm did not proceed with transplantation as one progressed to acute myeloid leukemia (baseline blast count 14%) and another experienced sudden death of unknown cause the day after starting ruxolitinib. In addition, there was one GF in the related arm. Due to these 3 failures in the related arm, further enrollment was stopped in this arm per protocol criteria. In the unrelated arm, there were 4 failures (Table 1), and the study met the protocol criteria for further enrollment.Mean percent reduction from baseline to day -9 in palpable spleen length below the left costal margin was 30% (p=0.04) in 12 patients with palpable spleen. 5/12 (42%) had any reduction, and 4/12 (33%) had ≥50% reduction. From baseline to best score on day -9 or day -5, 11/19 (58%) patients with data had any improvement in MPN-SAF Total Symptom Score, and 7/19 (37%) had ≥50% reduction.Of the 19 patients undergoing transplant, ruxolitinib was tapered off successfully in all patients with no significant withdrawal syndrome or delay in transplant noted. In the pre-transplant phase, most common Grade 3 or higher toxicity considered to be related to ruxolitinib was anemia (6/21, 29%), and one patient had legionella pneumonia deemed not related to ruxolitinib. Median time to neutrophil recovery (> 0.5 x 109/L) and platelet recovery (>20 x 109/L) was 19 and 19.5 days. By day 100, 7/19 (37%) experienced Grade 2-4 acute GVHD (G2 in 5, G3 in 2). In the first 30 days post HCT, most common Grade 3 or higher toxicity was febrile neutropenia seen in 5/19 (26%) patients.In all 21 patients from time of registration with median follow-up of 5.8 months, 6-mo overall survival was 75% (95% CI 44-90%). For the 19 transplant recipients, 6-mo OS was 83% (95% CI 55-94%) from date of transplant.Conclusions: Stage 1 trial results highlight important observations. First, ruxolitinib may not be suitable for all myelofibrosis patients pre-transplant, eg, alternative approaches might be more appropriate in the context of accelerating disease. Second, we demonstrated a safe approach for tapering ruxolitinib prior to transplant which allowed patients to commence conditioning with reduced spleen size and symptoms. Third, pre-transplant ruxolitinib does not appear to have any adverse impact on early post-HCT outcomes following unrelated donor transplant, although Stage 2 enrollment will be required to better assess the potential benefits of this approach. [Display omitted] DisclosuresGupta:Novartis: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Research Funding. Yacoub:Incyte: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Speakers Bureau; Alexion: Honoraria. Mesa:Promedior: Research Funding; Celgene: Research Funding; CTI: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy. Mead:Novartis: Honoraria, Research Funding, Speakers Bureau. Mascarenhas:Novartis: Other: DSMB , Research Funding; Roche: Research Funding; Promedior: Research Funding; Janssen: Research Funding; CTI Biopharma: Research Funding; Incyte: Other: Clinical Trial Steereing Committee, Research Funding.

Role of reduced-intensity conditioning allogeneic hematopoietic cell transplantation in older patients with de novo acute myeloid leukemia.

Reduced-intensity conditioning (RIC) regimens extend the therapeutic use of allogeneic hematopoietic cell transplantation (HCT) to older patients. The survival trend in 2325 patients aged >50years presenting with de novo acute myeloid leukemia (AML) who underwent first reduced-intensity HCT (RIC-HCT) was assessed by retrospectively analyzing outcomes between 2000 and 2013. The annual number of RIC-HCTs in Japan was higher in the 2008-2013 period (n = 205/year [1229/6years]) than in the 2000-2007 period (n = 137/year [1096/8years]). Overall and disease-free survival were higher in the 2008-2013 period (P < 0.001) because of the improvement in transplant-related mortality (TRM). Survival regarding RIC-HCT for AML has improved over time, with an increased number of RIC-HCTs in patients with a Karnofsky performance status (KPS) ≥80. However, TRM remains high and the relapse rate has not improved over time. Multivariate analyses showed that a KPS ≥80 and complete remission at HCT were associated with less TRM and relapse, and better survival regardless of age ≥65years. Accurate timing and prospective identification of patients at risk of TRM may aid the development of risk-adapted strategies for RIC-HCT in AML patients regardless of age.

Minor Antigen Vaccine-Sensitized DLI: In Vitro Responses Do Not Predict In Vivo Effects.

BackgroundWe reported on a pilot study of minor histocompatibility antigen vaccination using constructs expressing male-specific gene disparities of selected mouse CDNA on Y and sex determining region Y in the canine model. We performed reduced-intensity hematopoietic cell transplantation with female donors and male recipients, producing stable mixed donor-recipient hematopoietic chimeras. We then performed a vaccine series in three female transplant donors followed by donor lymphocyte infusion (DLI) into their respective mixed chimeras. One mixed chimera experienced a significant shift in the percentage of donor chimerism, but no response occurred in the other 2 recipients. We then hypothesized that inadequate donor sensitization was responsible for these results.MethodsTo test this hypothesis, we added 4 monthly booster vaccinations to 2 of the original hematopoietic cell transplantation donors, including the donor that drove the partial response, followed by a second DLI.ResultsStrong T cell responses were shown by ELISpot and confirmed by intracellular cytokine staining in both donors. A second DLI resulted in a further increase in donor chimerism in the same mixed chimera that experienced the previous increase, but no change in donor chimerism was again seen in the other recipient. Evaluation of RNA expression of the target antigens demonstrated that conversion occurred in the recipient that expressed both selected mouse CDNA on Y and sex determining region Y.ConclusionsT cell responses against Y chromosome-encoded disparities were not necessarily sufficient to drive in vivo female antimale responses. Other factors including the presence of specific haplotypes or the heterogeneous expression of the target antigen may affect T cell responses against minor histocompatibility antigens. These results warrant future vaccine studies in a larger transplant cohort using epigenetic modulation of the recipient to promote target gene expression.

Evaluation of allogeneic transplantation in first or later minimal residual disease – negative remission following adult-inspired therapy for acute lymphoblastic leukemia

Comparisons without hematopoietic cell transplantation (HCT) to myeloablative (MAC) or reduced-intensity HCT (RIC) for adults with acute lymphoblastic leukemia (ALL) in first minimal-residual-disease negative remission (MRDNeg CR1) are limited. Further, the importance of MRDNeg following salvage therapy (MRDNeg CR2+) is unknown. We evaluated 89 patients in MRDNeg CR1 after adult-inspired treatment: 33 received MAC (12 Philadelphia chromosome [Ph]+), 17 received RIC (13 Ph+), and 39 Deferred HCT (3 Ph+). Three-year overall survival (OS) estimates for MAC, RIC, and Deferred HCT were 71%, 69%, and 68%, while 3-year event-free survival (EFS) estimates were 65%, 54%, and 28%, respectively. Further, HCT in MRDNeg CR1 performed similarly to MRDNeg CR2+: 3-year OS estimates were 70% and 69%, and 3-year EFS estimates were 62% and 62%, respectively. In conclusion, adults with ALL in MRDNeg CR1 following adult-inspired therapy had similar OS with or without HCT, and HCT in MRDNeg CR2 + can yield long-term survival.

Prognostic factors to predict outcome of reduced intensity allogeneic haematopoietic cell transplantation for chronic lymphocytic leukemia.

Despite advances in immunochemotherapy CLL remains an incurable disease.. Allogeneic haematopoietic cell transplantation (HCT) has proven curative potential with ability to overcome adverse prognostic factors, however due to its toxicity it is generally perceived as the last option. We performed retrospective study to explore the outcomes and possible determinants of survival in the unselected consecutive cohort of 68 CLL patients (median age 59 years) receiving reduced intensity HCT as a part of salvage therapy in 2 Czech centers. The median interval from diagnosis to HCT was 69 months with median 3 of prior regimens, all patients were refractory to purine analogues. 49% of patients were transplanted with advanced (i.e. refractory or progressive disease or CR/PR>3), 38% had high risk cytogenetics. With median follow-up of 35 months the 3-year Kaplan-Meier survival probability for OS and PFS were 39% and 26%, respectively. Altogether 18 patients (26%) have relapsed or progressed. During the follow-up 41 patients died, 32 (78%) of transplant related factors (NRM), the others of relapse or disease progression.Univariate analysis failed to identify any clinical and pre- or post-transplant variables having clear prognostic significance for OS or PFS. The marginal OS advantage favoring HCT performed recently was detected (3-year OS: 31% for HCT until 2006 and 47% thereafter, p=0.0923). In multivariable hazards model only the female donors were associated with shorter OS (HR 2.278, p=0.016) whereas transplanted T-cell> 2.75x108/kg predicted inferior PFS(HR 1.957, p=0.035). No prognostic impact of donor type, age of donor and recipient, HLA mismatch, disease status pre-HCT, number of previous therapy lines, interval from dg. to HCT and number of transplanted hematopoietic cells was found. Our findings support the conclusion that alloHCT is able to overcome well known negative cytogenetic prognostic factors and that preferring male to female donors could be beneficial.