Myeloablative Stem Cell Transplantation Research Articles

Thiotepa/cyclophosphamide (TT/Cy) preparative regimen for patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic stem cell transplantation.

6556 Background: Total body irradiation (TBI)-based preparative regimens have been standard for patients with ALL undergoing allogeneic stem cell transplant (SCT). It is unclear if chemotherapy-only regimens are equally efficacious. Here, we present the largest reported experience with myeloablative TT/Cy in patients with ALL undergoing allogeneic SCT and compare outcomes with TBI-based regimens. Methods: Patients with ALL receiving myeloablative allogeneic SCT at Indiana University from 2007-2020 were included. TT/Cy consisted of TT 15 mg/kg and Cy 120 mg/kg. TBI/Cy consisted of 13.2 Gy in 8 fractions and Cy 3600 mg/m2 or etoposide 60 mg/kg. The primary endpoint was overall survival (OS). Secondary endpoints included relapse-free survival (RFS), engraftment, and toxicities within the first 100 days. Median follow up for surviving patients is 2,532 (range 599-4,762) days. Results: 80 patients with ALL of median age 40 (range 22-59 years) received conditioning with TT/Cy (n=25) versus TBI/Cy or TBI/etoposide (n=55). Baseline characteristics were similar. For patients receiving TT/Cy, the median OS was not reached, and the 4-year OS was 54.5% (95% confidence interval [CI], 34.3-74.7%), compared with a median OS of 1,491 days and a 4-year OS of 50.9% (95% CI, 37.8-64.2%) for those receiving TBI-based conditioning (p=.75). Similarly, for TT/Cy patients, the median RFS was 847 days and 4-year RFS was 43.2% (95% CI, 23.4-63%), not significantly different from median RFS of 1491 days and 4-year RFS 50.2% (95% CI 36.9-63.5; p=.232) for recipients of TBI regimens. On multivariable analysis, only a higher disease risk index was associated with significantly worse OS (p<.001), while conditioning regimen was not predictive of OS. Similarly, there was no significant difference in RFS between TT/Cy and TBI-based regimens on either univariable or multivariable analysis. Secondary endpoints are summarized in the table. As shown, TT/Cy was associated with significantly lower incidence of mucositis, TPN usage, bacterial infection, sinusoidal obstruction syndrome (SOS), and longer length of stay of primary transplant admission. Conclusions: While there was no significant difference in OS or RFS for patients receiving either TT/Cy or TBI-based conditioning, TBI was associated with greater toxicity. Our data suggests that TT/Cy is an acceptable alternative to TBI-based conditioning for ALL patients undergoing myeloablative allogeneic SCT. [Table: see text]

Improved survival for myeloid malignancy patients receiving thiotepa/cyclophosphamide (TT/Cy) versus total body irradiation/cyclophosphamide (TBI/Cy) conditioning and allogeneic stem cell transplantation.

6555 Background: TBI/Cy is a commonly used conditioning regimen prior to allogeneic stem cell transplant (SCT). Chemotherapy only regimens, mostly containing busulfan, have been shown to be effective and less toxic in patients with myeloid malignancies. Here, we present the largest reported experience with a non-busulfan myeloablative chemotherapy regimen of TT/Cy in myeloid malignancy patients undergoing allogeneic SCT and compare outcomes with TBI/Cy. Methods: Patients with myeloid malignancies receiving allogeneic SCT at Indiana University from 2007-2020 were included. TT/Cy consisted of TT 15 mg/kg and Cy 120 mg/kg. TBI/Cy consisted of 13.2 Gy in 8 fractions and Cy 3600 mg/m2. The primary endpoint was overall survival (OS). Secondary endpoints included relapse-free survival (RFS), engraftment, and toxicities within the first 100 days. Median follow up for surviving patients is 2,046 (range 816-5,572) days. Results: 225 patients with AML (n=160), CML (n=45), and MDS (n=30) of median age 44 (range 19-59 years) received conditioning with TT/Cy (n=159) or TBI/Cy (n=66). Baseline characteristics were similar. For TT/Cy patients, the median OS was not reached, and 4-year OS was 57.2% (95% confidence interval [CI], 49.2-65.2%), which was significantly better than with TBI/Cy, with median OS 373 days and 4-year OS 33.9% (95% CI, 22.3-45.5%; p<.001). Similarly, for TT/Cy patients, the median RFS was not reached and 4-year RFS was 59.2% (95% CI, 52-67.2%), significantly better than median RFS of 341 days and 4-year RFS 35.2% (95% CI, 23.7-46.9%; p<.001) for recipients of TBI/Cy. On multivariable analysis adjusting for age, sex, diagnosis, disease risk, comorbidity index (HCI), and degree of stem cell source, TT/Cy had significantly lower risk of death (HR 0.44, 95% CI, 0.30-0.65; p<.001) together with female sex (p=.03) and lower HCI (p=.046). As shown in the Table summarizing secondary endpoints, TBI/Cy was associated with significantly higher rates of mucositis, sinusoidal obstruction syndrome (SOS), TPN usage, multiorgan failure, and length of stay of primary admission. Conclusions: TT/Cy is an efficacious regimen for patients with myeloid malignancies undergoing myeloablative allogeneic SCT with less toxicity and improved RFS and OS compared with TBI/Cy. TT/Cy should be compared to other non-TBI containing busulfan-based regimens. [Table: see text]

Treatment pattern and outcomes of re-induction therapy prior to stem cell transplantation in patients with relapsed/refractory multiple myeloma in Germany

There are limited data guiding choice of re-induction therapies for patients with relapsed/refractory multiple myeloma (RRMM) prior to stem cell transplantation (SCT). We performed a retrospective medical chart review of 171 patients with RRMM in Germany who received re-induction therapy in second line (78%; n = 134) or third line (22%; n = 37) prior to re-SCT. Index therapy was defined as first completed re-induction therapy for planned myeloablative conditioning and SCT in second/third line within the eligibility period (1/2016–12/2019). Most common pre-index first line and maintenance therapy used were bortezomib-based combinations (91%; n = 155/171) and lenalidomide (55%; n = 29/53), respectively. Median duration of index therapy line was 9 months; carfilzomib-based combinations were the most widely used in second/third line re-induction therapy (49%; n = 83/171), followed by daratumumab-based combinations (21%; n = 36/171). Overall response rates in second/third line were 87% after re-induction and 96% after SCT; median time to next treatment line after start of index therapy was 31 months; median progression-free survival (PFS) was 29 months; and median overall survival after index date was not reached. Based on these data, re-induction therapy with salvage SCT appears to be beneficial in selected patients with RRMM in clinical practice in Germany, translating into deep responses, long PFS and prolonged time to next treatment.

Kidney Disease Following Hematopoietic Stem Cell Transplantation.

Hematopoietic stem cell transplantation (SCT) provides a curative option for the treatment of several malignancies. Its growing use is associated with an increased burden of kidney disease. Acute kidney injury is usually seen within the first 100days of transplantation and has an incidence ranging between 12 and 73%, with the highest rate in myeloablative allogeneic SCT. A large subset of patients after SCT develop chronic kidney disease. They can be broadly classified into thrombotic microangiopathy, nephrotic syndrome, and calcineurin toxicity. Dialysis requirement after SCT is associated with mortality exceeding 80%. Given the higher morbidity and mortality related to development kidney disease, nephrologists need to be aware of the various causes and best treatment options.

Infusion of iPSC-Derived CD34 + Hematopoietic Progenitors Following Myeloablative HSC Transplantation and Assessment of Their Immunogenicity in MHC-Defined Nonhuman Primate Model

Bone marrow suppression and associated neutropenia that renders the patient more susceptible to infection is a major complication and limiting factor for current chemotherapy. Strategies aimed at neutrophil reconstitution using transfusions or accelerating neutrophil recovery with G-CSF show a limited effect in reducing the rate of infection. To overcome these limitations, administration of ex vivo expanded somatic hematopoietic progenitors (HPs) has been explored as a way to facilitate a more rapid myeloid recovery and improve overall survival following myeloablation. Recent advances in reprogramming and induced pluripotent stem cell (iPSC) technologies have created alternative platforms for off-the-shelf supply of immunologically compatible HPs, including cellular products derived from MHC homozygous superdonors which can increase the degree of MHC matching and may provide a maximum utility for stem cell banking. In these studies, we developed Mauritian cynomolgus macaque (MCM) model to evaluate the utility and safety of CD34 +CD45 + hematopoietic progenitors derived from iPSCs (iHPs) generated from MHC homozygous animals in the treatment of cytopenia following myeloablative stem cell transplantation. MCM iPSCs were generated from MHC homozygous animals and used to generate iHPs in coculture with OP9. Three groups of MCMs underwent myeloablative total body irradiation (TBI) followed by transplantation of cryopreserved autologous CD34 + HSPCs. Four days after autologous HSPC transplantation, animals received transfusion of 30x10 6/kg cryopreserved iCD34 + cells tagged with eGFP or tdTomato from homozygous MHC-matched iPSCs (group 2) or homozygous MHC mismatched iPSCs (group 3). We have demonstrated that infusion of iHPs is safe and well tolerated. No teratoma or tumor formation was observed in animals one year after infusion of iHPs. Although we detected few iPSC derived hematopoietic cells in the blood within 1-week post-infusion, we did not see any significant differences in blood counts or other peripheral blood parameters between all animal groups. Intriguingly we found footprints of iPSC-derived cells in the colon, lymph node, skin and brain specimens collected 25 days after iHP infusion from one animal. This suggests a possibility of migration and retention within these tissues of iHP and iHP-derived myeloid cells. To assess immunogenicity, MHC homozygous iHPs were infused into immunocompetent MCMs across different MHC barriers. 10x10 6/kg of cryopreserved iCD34+ from homozygous iPSCs were transfused every week for 3 weeks, into animals that were divided into 4 groups namely autologous (group I), MHC matched homozygous (group II), MHC matched heterozygous (group III) and MHC mismatch (group IV). Overall, these studies revealed low immunogenicity of MHC homozygous iHPs in MHC matched homozygous and heterozygous animals, while weak immune response was detected following iHP infusion in some MHC mismatched animals. DisclosuresSlukvin: Cynata Therapeutics: Consultancy, Current equity holder in publicly-traded company.

Thiotepa-Busulfan-Fludarabine in Comparison to Busulfan-Cyclophosphamide As Myeloablative Conditioning Regimen Pre Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia: A Study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Background. Busulfan plus Cyclophosphamide (BuCy) is the traditional myeloablative conditioning (MAC) regimen pre allogeneic stem cell transplantation (SCT) for acute myelogenous leukemia (AML). The Thiotepa, Busulfan, Fludarabine (TBF) protocol was initially developed for cord blood SCT and subsequently employed in haploidentical SCT; however, there is limited data assessing the TBF regimen in SCT from sibling (MSD) and unrelated donor (URD) for AML and no comparison between the two preparative protocols has been performed.Patients and methods. We analyzed transplantation outcomes of 2523 adult patients (pts) with AML in remission (CR1, CR2+) aged 18-50 years that underwent a first SCT from MSD or URD between 2007 and 2015 and reported to the ALWP of the EBMT. One hundred and three patients received TBF and 2370 pts received BuCy. Pts who received oral busulfan, manipulated grafts, or transplant from <=8/10 HLA-matched donor were excluded. All pts received MAC regimen (defined by Busulfan dose>=9.6 mg/kg). As compared to BuCy, the TBF group included significantly older pts, who were transplanted more recently, had longer interval from diagnosis to transplant, and were more likely to have received BM as stem cell source and URD as donor type. In order to minimize the bias due to differences in pts characteristics, a 1:3 pair-matched analysis was performed. One hundred and forty-six pts receiving TBF were compared with 438 pts receiving BuCy; matching factors included age, year of SCT, disease status at SCT, interval from diagnosis to SCT, donor type, CMV serostatus of both the donor and patient, stem cell source, GVHD prophylaxis and use of anti-thymocyte globulin.Results. With a median follow-up of 22 months, incidence of grade II-IV and III-IV aGVHD after TBF vs BuCy was 29% vs 23% (p=0.23) and 15% vs 8% (p=0.04), respectively. The 5-year cumulative incidence of cGVHD and severe cGVHD was 36% vs 43% (p=0.66) and 16% vs 22% (p=0.72) for TBF vs BuCy, respectively. The 1-year and 5-year non-relapse mortality (NRM) rates were 10% and 22% for TBF vs 9% and 13% for BuCy, respectively (p=0.36). The 1-year and 5-year relapse incidence (RI) rates were 17% and 25% for TBF vs 21% and 37% for BuCy, respectively (p=0.32). No significant difference was observed in leukemia-free survival (LFS), being the 1-year and 5-year LFS rates 73% and 53% for TBF vs 70% and 50% for BuCy, respectively (p=0.56). Overall survival (OS) was also similar, being 80% and 54% for TBF vs 79% and 59% for BuCy, respectively (p=0.88). The composite endpoint graft-vs-host disease-free, relapse-free survival (GRFS) at 5 years was 48% for TBF and 40% for BuCy (p=0.48). Notably, when the analysis was restricted to pts in CR1, a significant difference in RI rate was observed (1-year and 5-year RI: 10% and 18% for TBF vs 20% and 38% for BuCy, respectively, p=0.003) leading to a trend for better LFS for TBF as compared to BuCy (1-year and 5-year LFS: 78% and 57% for TBF vs 72% and 50% for BuCy, respectively, p=0.07), with no difference in OS. When examining separately pts receiving SCT from MSD or URD, no significant difference was observed between TBF and BuCy regimens in terms of transplant outcome. In multivariate analysis, TBF was associated with lower RI compared to BuCy (HR 0.6, p=0.02), while no difference was observed in terms of NRM, LFS, OS and GRFS (HR 0.8, p=0.12 for GRFS). TBF was also associated with lower incidence of cGVHD (HR 0.7, p=0.04) and a trend for lower incidence of severe cGVHD (HR 0.6, p=0.1); on the contrary we observed a trend for higher incidence of grade III-IV aGVHD following TBF as compared to BuCy (HR 1.79, p=0.06).Conclusions. These results suggest that TBF is a valid myeloablative conditioning pre MSD or URD SCT for AML pts < 50 years of age and in remission, with similar transplantation outcome as compared to the traditional BuCy preparative regimen. These data may serve as the scientific background for a well designed randomized two arm study comparing TBF to BuCy as MAC pre SCT in AML pts below the age of 50 years in CR. [Display omitted] DisclosuresSavani:Jazz Pharmaceuticals: Speakers Bureau.

Phase II Study of High Dose Cytarabine Followed By Pembrolizumab in Relapsed/Refractory Acute Myeloid Leukemia (AML)

Introduction: Outcomes are dismal for patients (pts) with relapsed/refractory (R/R) AML. Innate and adaptive immune aberrations exist in AML pts leading to immune escape. We have previously shown that there is an increased expression of multiple co-inhibitory molecules including programmed death-1 (PD-1) in the peripheral blood of AML pts at diagnosis, and these levels persist in pts with refractory disease (Knaus H, et al. Blood [Abstract] 2015). We hypothesized that administration of pembrolizumab after high dose cytarabine (HiDAC) salvage chemotherapy would stimulate a T-cell mediated anti-leukemic immune response leading to improved efficacy in R/R AML.Methods: A multicenter phase II study of age-adjusted HiDAC (<60 years: 2 gm/m2 IV Q12hours days 1-5; >=60 years: 1.5 gm/m2 IV Q12hours days 1-5) followed by pembrolizumab 200 mg IV on day 14 is being conducted in R/R AML pts 18-70 years. The primary endpoint of this study is the rate of complete remission (CR)/CR with incomplete recovery (CRi) after HiDAC followed by pembrolizumab. The study design is a Simon's like two-stage design (n=37 pts) with relaxed stopping for futility. Relaxed stopping refers to overall response rate (CR/CRi+partial remission [PR]) when stopping rule for futility is applied in the first stage. The null hypothesis that the CR/CRi rate for HiDAC followed by pembrolizumab is 20% will be tested against a one-sided alternative hypothesis yielding a type 1 error rate = 5% and power = 84% when the CR/CRi rate of HiDAC followed by pembrolizumab = 40%. Continuous monitoring for toxicity will be performed to assess for unacceptable toxicity. Overall responders will receive maintenance phase pembrolizumab 200 mg IV Q3weeks for up to 2 years until relapse/progression. Pts can proceed to allogeneic stem cell transplant (SCT) before or after maintenance phase (SCT must be >=30 days from last dose of pembrolizumab). Correlative studies include serial peripheral blood and bone marrow flow cytometry, mRNA-sequencing, and T cell receptor (TCR) clonality studies to determine predictive biomarkers of response.Results: 13 pts enrolled on this study between August, 2016-July, 2017 (Table 1). There have been 0 unacceptable toxicities to date. Immune-related adverse events have included grade 2 hyperbilirubinemia (n=1), grade 3 hepatic enzymes (n=1), both resolved promptly after systemic corticosteroids, as well as self-resolving grade 3 rash (n=1). Additionally, 1 pt developed grade 3 pulmonary edema without evidence of pneumonitis that resolved spontaneously without steroids. Of the 10 evaluable pts (as of July 1, 2017), overall response rate = 50% (CR/CRi: 4/10= 40%; PR = 1/10=10%), meeting the threshold to proceed to stage 2. Two pts have proceeded to a myeloablative allogeneic SCT in CR (one of whom received 2 cycles of maintenance pembrolizumab) and remain in CR. Post-SCT, both pts developed steroid-responsive acute GVHD of skin, one pt developed a transient increase in hepatic enzymes that was responsive to steroids, and one pt developed moderate chronic GVHD. Four pts have received maintenance pembrolizumab: 2 pts relapsed (median duration of CR = 3.9 months; range: 2-5.7 months), one pt proceeded to SCT after 2 cycles, and one pt initially achieved a PR and remains with stable disease after 11 cycles of maintenance pembrolizumab. No pts have died in remission. 30-day and 60-day mortality = 0% and 10%, respectively. Preliminary findings from the first 6 pts (3 responders vs. 3 non-responders) revealed increased diversity of TCR Vβ repertoire from pre-treatment peripheral blood CD8+ T-cells in responders when compared with non-responders using Shannon entropy analysis (p=0.0058; Figure 1).Conclusions: Early results of a multicenter phase II study demonstrate the feasibility of adding immune checkpoint blockade with pembrolizumab after HiDAC chemotherapy in R/R AML. An overall response rate of 50% is encouraging in a high-risk R/R AML cohort though ongoing findings are imperative to evaluate the efficacy and future role of pembrolizumab in AML. Interestingly, in a small cohort of patients, broadening of the immune repertoire, perhaps by increasing T cell responses beyond endogenous viral responses, was associated with response to PD-1 blockade. Future directions include a comprehensive immune biomarker discovery approach to determine predictors of response to immune checkpoint blockade in AML. [Display omitted] DisclosuresZeidner:Tolero Pharmaceuticals: Honoraria; Agios: Honoraria; Merck: Research Funding; Takeda: Research Funding; Tolero Pharmaceuticals: Research Funding; Celgene: Honoraria. Vincent:Merck: Research Funding; Pharmacyclics: Research Funding; Nanostring: Membership on an entity's Board of Directors or advisory committees. Foster:Shire: Honoraria; Incyte: Honoraria; Macrogenics: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Pfizer: Research Funding; Celator: Research Funding. Coombs:Pharmacyclics: Honoraria; H3 Biomedicine: Honoraria. Gojo:Merck: Research Funding; Amgen: Research Funding; Amgen: Honoraria; Novartis: Research Funding. Serody:Merck: Research Funding.

Long--Term Free Survival of Two Class III β-Thalassemic Patients after Non-Myeloablative Stem Cell Transplantation

At present, hematopoietic stem cell transplantation is the only curative treatment for β thalassemia patients. Conventional myeloablative stem cell transplantation is associated with significant morbidity and mortality, and non-myeloablative stem cell transplantation is associated with high graft failure rate. Some modification in this treatment approach can result in successful transplantation in thalassemia patients. Two successful Fludarabine-based non-myeloablative stem cell transplantation in two Class III β thalassemia patients are reported here. The first patient was a 14-year old girl that developed rapid engraftment and full chimerism after rapid tapering of cyclosporine as graft-versus-host disease (GVHD) prophylaxis drug according to our protocol. Another patient was a 24-year old female patient that developed cyclosporine toxicity, and early tapering of cyclosporine helped for rapid engraftment and successful transplantation. After these two successful experiments in non-myeloablative peripheral blood stem cell transplantation for our class III β thalassemia patients, we concluded that Fludarabine-based non-myeloablative stem cell transplantation with adequate number of stem cells at the time of transplantation and rapid tapering of GVHD prophylaxis drugs after transplantation can potentially help for rapid engraftment and successful stem cell transplantation in high risk β-thalassemia patients.

Mapping the Road of Gvhd and GVT: A Longitudinal Study of Immune-Transcriptome Signatures As Novel Approach to Solve Post-Allogeneic Hematopoietic Cell Transplantation Dilemmas

Introduction Allogeneic Hematopoietic Cell Transplantation (allo HCT) is currently the only curative therapy for high-risk hematologic malignancies due to the immune response of the donor cells against the malignant cells (graft versus tumor effect; GVT), but with the cost of Graft Versus Host Disease (GVHD). Despite extensive research, very few predictors of GVHD and GVT have been identified to date. Additionally, clinical GVHD diagnosis can be challenging due to chemotherapy-related or infection-related organ toxicity manifestations, which further complicate prediction and treatment stratification algorithms. In order to study the mechanisms of GVHD and GVT and to identify potential GVHD markers we apply a novel approach, called Transcriptome Fingerprint Assay (TFA), relying on high frequency sampling and blood transcript profiling. The TFA is a multiplex microfluidics q-PCR based assay linked with a computational model for modular functional transcriptome analyses, uniquely tailored to answer complex questions on immune perturbations through frequent profiling of gene expression signatures from &lt; 1 ml of blood (Chaussabel and Baldwin. Nat Rev Immunol 2014, Speake et al. Clin Exp Immunol 2017). This approach has been successfully applied to stratify patients' prognosis in autoimmune and infectious diseases (Banchereau R et al. Cell 2016, Dunning et al. Nat Immunol 2018). In our study we use the TFA to capture longitudinal immune signatures as dynamic "snapshots" of the patient's immune system after HCT. Hypotheses Fluctuations over-time in gene expression of allo HCT patients' immune system reflect the pathologic/disease control programs (GVHD/GVT) and may be used to identify diagnostic and predictive biomarkers. GVHD/GVT control immune programs depend on the "inner" interface between the donor immune-system and the recipient, and are influenced by external variables, as infections or drugs. These variables can affect the immune system-related gene expression and can be measured. Objectives To systematically measure gene expression signatures in immune perturbations post-allo HCT, in order to: Identify GVHD-related immune signatures consistent with clinical diagnosis of GVHD.Predict and stratify therapy-resistant GVHD and severe chronic GVHD, according to immune signatures.Identify links (causative and consequential) between GVHD, GVT, relapse, and other post-transplant immune perturbations (e.g. infections). Methods Enroll 250 allo HCT patients to populate a "GVHD cohort" and a "non-GVHD cohort" of 50 patients each, and 50 donors (healthy controls cohort) . Patients donate micro-quantities of blood (50 to 600 microliters), weekly until day 100 post-transplant and every 2 weeks thereafter until 2 years after transplant. Detailed clinical, laboratory and therapy annotations are captured during the follow-up. Gene expression of 264 immune-related genes for each sample are measured through Fluidigm BioMark high throughput qPCR system, and normalized to the geometric mean Ct of 8 housekeeping genes. Data interpretation is performed through TFA modular analyses and correlated with the clinical annotations. Results Results of three series of patients' samples are shown to exemplify the potential of TFA as a method to study the mechanisms of GVHD and GVT. All three patients underwent myeloablative peripheral blood stem cell transplant from an HLA identical sibling donor. Two patients developed steroid responsive-acute GVHD (patient #1: GVHD stage I was diagnosed on day 38 post HCT, patient #4: GVHD stage III was diagnosed on day 21 post HCT). One patient (Patient #6) did not develop clinical GVHD, but routine skin biopsy on day 80 revealed apoptotic cells consistent with subclinical skin GVHD. Principal Component Analysis (PCA) of the three patients' series is shown in Figure 1, the dynamic transcriptomes according to TFA modules of patients #1 and #6 are shown in Figure 2, and representative TFA modular fingerprints are shown in Figure 3. Conclusion We anticipate that using the TFA approach will help to fill knowledge gaps instrumental to solve clinical dilemmas related to allo HCT complications, and to improve the clinical outcomes of allo HCT patients. Disclosures No relevant conflicts of interest to declare.

Post-transplant cyclophosphamide in matched and haploidentical transplant recipients receiving myeloablative timed sequential busulfan conditioning regimen: Results of a phase II study.

7007 Background: Myeloablative stem cell transplants have a lower rate of relapse than reduced intensity regimens. Timed sequential busulfan (TSB) with fludarabine (Flu) is a promising myeloablative regimen for patients undergoing matched sibling (MSD) or unrelated (MUD) donor transplantation (HCT) with low non-relapse mortality (NRM) (Popat et al Lancet Haematology 2018), but was not tested in haploidentical (haplo). Also, whether this approach can be used with post-transplant cyclophosphamide (PTCy) in MSD, MUD and haplo HCT is unknown. To address these issues, we conducted a prospective phase II study. Methods: Patients with hematological malignancies with MSD, MUD or haplo donor were eligible. They received fixed doses of Busulfan(BU) 80mg/m2 either on day -13 and -12 (n=45) or on -20 and -13 (n=10). Then, Flu 40mg/m2 was given on day -6 to -2 followed by Bu dosed to achieve target area under the curve (AUC) of 20,000 umol/min for the whole course based on pharmacokinetic studies. Thiotepa 5mg/kg was given on day -7 to haplo group. GVHD prophylaxis was PTCy 50mg/kg on day 3 and 4 and tacrolimus. Haplo and later MUD recipients also received mycophenolate mofetil. Results: 55 patients with a median age of 47 (15-65) years were enrolled. 30 patients had AML or MDS, 9 CML or MPD, 5 lymphoma, 5 myeloma and 6 ALL. About half had haplo 26 (47%); others had MUD 18 (33%) or MSD 11(20%). Disease risk index was high in 18 (32%), intermediate in 32 (58%), and low in 5 (9%) patients. Comorbidity score was ≥3 in 22 (40%) patients. With a median follow up of 17 months (5-28), 1-year OS, PFS, NRM and relapse rates were 71% (60-84%), 63% (51-77%), 20% (9-31%), and 17% (7-27%), respectively [Table]. There were no graft failures. Day 100 grade II-IV and III-IV acute GVHD rates were 38% (25-51%) and 9% (95% CI 1-17%), respectively; 1-year chronic GVHD and extensive chronic GVHD rates were 10% (2-28%) and 8% (0-15%), respectively. 1-year OS in MSD, MUD and haplo groups were 91% (75-100%), 72% (54-96%), and 62% (45-83%) respectively (P=0.11). Conclusions: Myeloablative TSB with PTCy is feasible in MSD, MUD and haplo HCT. It lowers the incidence of severe acute and chronic GVHD without apparent increase in relapse. Clinical trial information: NCT02861417. [Table: see text]

Host skin T cells survive stem cell transplant conditioning and are functional during acute GVHD

Abstract Graft-versus-host-disease (GVHD) is a major cause of morbidity and mortality in stem cell transplantation (SCT). Acute GVHD is thought to be mediated by donor T cells that target and destroy host tissues. Studies into the host immune system are limited, as it is assumed that host T cells in peripheral tissues such as skin are depleted by conditioning regimens in parallel to T cells in lymphoid organs and blood. However, it is recently appreciated that a high number of memory T cells reside long-term within the organs most affected by GVHD. We investigated whether host skin T cells survive SCT conditioning and are present during acute GVHD. To do so, excess skin biopsy tissue was obtained from patients with acute skin GVHD who had undergone myeloablative or non-myeloablative conditioning and allogeneic SCT with sex-mismatched donor cells. Tissue was stained for T cell markers via immunofluorescence concurrently with in situ hybridization for the X and Y chromosomes. All seventeen patients studied demonstrated persistence of host T cells in skin, often in equal or greater numbers than donor T cells. Host skin T cells survived regardless of myeloablative or non-myeloablative conditioning, of patient age, and of day post-SCT (samples ranged from 12–213 days post-SCT). Comparatively, blood T cell chimerism was 100% donor in nearly all samples, indicating diverging effects of conditioning on T cell compartments. Skin host T cells demonstrated pro-inflammatory cytokine production. These results provide a novel avenue of research into GVHD pathobiology and suggest that alternative conditioning regimens should be employed if host skin T cells are to be targeted.

Association of Pre-Allogeneic Hematopoietic Stem Cell Transplant 25-Hydroxy-Vitamin D Level and Development of Acute Skin Graft-Versus-Host-Disease: A Retrospective Analysis of 154 Patients

IntroductionAcute graft versus host disease (aGVHD) is a leading cause of morbidity and mortality in patients who undergo allogeneic hematopoietic stem cell transplant (SCT). aGVHD is thought to be initiated when donor T cells encounter recipient antigen presenting cells (APC) such as dendritic cells (DC) and become activated. Preclinical studies have shown that vitamin D (VD) inhibits DC maturation biasing T cell proliferation towards tolerating rather than alloreactive T cell populations [Rosenblatt et al. BMT 2010]. A study of 53 patients who underwent myeloablative (ABL) SCT showed pre-SCT VD <25 ng/mL was associated with increased cumulative incidence (CI) of chronic GVHD but not for aGVHD [Glotzbecke et al. BMT.2013]. Another study evaluating day-30 VD levels post-SCT in 54 patients showed that VD < 20 ng/mL was associated with increased risk of acute skin GVHD, but only in patients who underwent reduced intensity conditioning (RIC) [Ganetsky et al. Abstract # 416. BBMT. 2014]. Given the conflicting data of the effect of VD on the incidence of aGVHD, and small sample size of prior studies, we performed a retrospective analysis to evaluate whether pre-HSCT serum vitamin D levels were associated with acute skin GVHD in patients undergoing both ABL and RIC SCT.MethodsOne hundred fifty-four patients at the University of Texas Southwestern (UTSW) Medical Center who had serum samples banked prior to RIC or ABL conditioning and then underwent matched related (MRD) or unrelated (MUD) SCT from December 2007 to December 2014, were included in the analysis. CI of acute skin GVHD grade II-IV (asGVHD) was assessed within 100 days post-SCT. VD cutoff of 25 ng/mL was chosen based on receiver operating curve (ROC) analysis from a prior study [Glotzbecke et al. BMT.2013].The shape and distribution of continuous variables was examined. Mean and standard deviations were calculated for continuous variables and percent’s calculated for categorical data. The χ2-test and Fisher’s exact test were used to compare categorical variables and Student’s t-test was used to compare parametric data and calculate p values. Stratified analysis was performed to evaluate for presence of interaction between dichotomous VD variable and other covariates. Statistically significant interaction was found between VD levels and ABL vs. RIC regimens. We therefore stratified analysis of our primary endpoint, CI of grade II-IV asGVDH, into RIC and ABL groups. Kaplan-Meir (KM) curves for CI of asGVHD were constructed with death and relapse and competing factors. Difference between CI curves was tested using the Gray method.ResultsOut of 154 patients, 93 (60.3%) were male, mean age was 51 (range 20-72) and mean VD was 22.6 (range 7.6-63.6). Overall CI of asGVHD was 24%. Most patients (112, 72.7%) had with VD <25 ng/mL (VD<25). On bivariate analysis, conditioning regimen (ABL vs RIC), donor type (MRD vs MUD), cell source (peripheral blood vs bone marrow), age at SCT, and ABO compatibility were similar among those with VD levels <25 and ≥25. CI of asGVHD was 22.0% and 25.0% in VD≥25 and VD<25 groups, respectively (p=0.696).Patients were then analyzed separately with respect to type of conditioning regimen they received (ABL and RIC). The ABL group had 79 patients with CI of asGVHD of 29.1% versus 18.6% in the 75 patients of the RIC group (p=0.12). In the ABL group, CI of asGVHD with VD≥25 was 40% versus 27.1% in VD<25 (p=0.4). In RIC group, CI of asGVHD with VD≥25 was 4.8% versus 24.1% with VD <25 (p=0.095).Figure 1A shows that in the ABL group the CI of asGVHD appears increased in patient with VitD≥25 (40% vs 27.1%, p=0.27). In contrast, Figure 1B shows that in the RIC group, the CI of asGVHD is higher for those with VD<25 (4.8% vs 24.1%, p=0.05).ConclusionPre-SCT VD level was not associated with asGVHD, however there was a trend toward significance in patients who underwent RIC with a VD<25mg/mL. After accounting for competing factors, KM analysis showed that in patients who undergo RIC, VD level < 25 ng/mL is associated with a statistically significant increased risk of developing asGVHD. Interestingly, VD > 25 may be associated with increased risk of asGVHD in patients who underdo ALB conditioning, although these results were not statistically significant. This is the largest study analyzing the association of peri-SCT VD levels and GVHD to date. Further studies to clarify the interaction between VD status, conditioning regimen and development of asGVHD are warranted. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Research progress of reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation in treatment of myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation(allo-HSCT) is likely to be the optimum method to cure international prognostic scoring system (IPSS) intermediate and high-risk patients with myelodysplastic syndrome(MDS). However, patients suffered with MDS are usually too old to undergo myeloablative conditioning allogeneic stem cell transplantation(MAC-HSCT). On account of its advantages of higher efficiency and lower toxicity, reduced intensity conditioning allogeneic stem cell transplantation(RIC-HSCT) is widely applied in the treatment of MDS patients. Currently, fludarabine plus alkylating regimens are widely applied, but the clinical outcomes are different from each regimen. Although RIC-HSCT has unique advantages in treating intermediate and high-risk elder MDS compared with MAC-HSCT and non-HSCT therapy, whether the outcome is influenced by factors such as tumor burden, recipient age, IPSS risk stratification, type of allo-HSCT, and comorbidity before transplantation is still unclear. In this article, we review literatures on RIC-HSCT in treatment of MDS. Key words: Myelodysplastic syndrome; Transplantation conditioning; Hematopoietic stem cell transplantation

Evaluation of the Pharmacokinetics and Efficacy of a Busulfan Test Dose in Adult Patients Undergoing Myeloablative Stem Cell Transplant

Evaluation of the Pharmacokinetics and Efficacy of a Busulfan Test Dose in Adult Patients Undergoing Myeloablative Stem Cell Transplant

Host Foxp3+CD4+ Regulatory T Cells Act as a Negative Regulator of Dendritic Cells in the Peritransplantation Period.

Host Foxp3+CD4+ regulatory T cells (Tregs) have been shown to suppress graft-versus-host disease (GVHD) in experimental bone marrow transplantation (BMT) models; however, the detailed mechanism is unknown. To address this issue, we established a murine MHC-haploidentical BMT model (BDF1 (H-2b/d) → B6C3F1 (H-2b/k)), in which transplantation following conditioning with high-dose (13 Gy) or low-dose (5 Gy) total body irradiation corresponds to myeloablative stem cell transplantation (MAST) or reduced-intensity stem cell transplantation (RIST) BMT. All MAST recipients died of GVHD within 70 d, whereas RIST recipients developed almost no GVHD and survived for at least 3 mo. In this BMT model, we investigated the kinetics of immune cells in the mesenteric lymph nodes because GVHD was most prominent in the intestines. Host Tregs that survived after total body irradiation could proliferate transiently by day 4. Comparing the kinetics of immune cells among MAST, RIST, and anti-CD25 mAb-treated RIST, we found that the transiently surviving host Tregs were fully functional, closely contacted with host dendritic cells (DCs), and significantly restrained the maturation (CD80 and CD86 expression) of DCs in a dose-dependent manner. There was a positive correlation between the ratio of DCs to host Tregs and the extent of maturation of DCs. Host Tregs suppressed alloresponse mainly by contact inhibition. Host Tregs are already active in lymph nodes before transplantation and restrain the maturation of host DCs, thereby dampening the ability of DCs to activate allogeneic donor T cells and consequently reducing the magnitude of graft-versus-host reaction. Thus, host Tregs are negative regulators of host DCs that act in the peritransplantation period.

Abstract IA13: Engineered T cells for cancer therapy

Abstract Patients with multiply relapsed or refractory chronic lymphocytic leukemia (CLL) have a limited survival. Chimeric antigen receptor (CAR)-modified T cells targeting CD19 may overcome the limitation of low complete response rates with conventional therapies with the potential to induce sustained remissions in patients with refractory B-cell malignancies. We previously reported preliminary results on three patients with refractory CLL. Here we report the mature results from our initial trial using CAR modified T cells to treat 14 patients with relapsed and refractory CLL (1). Autologous T cells transduced with a CD19-directed CAR (CTL019) lentiviral vector were infused into patients with relapsed/refractory CLL at doses of 0.14–11 ×108 CTL019 cells (median 1.6 x 108 cells). Patients were monitored for toxicity, response, expansion and persistence of circulating CTL019 T cells. The overall response rate in these heavily pretreated CLL patients was 8/14 (57%), with 4 complete remissions (CR), and 4 partial remissions (PR). The in vivo expansion of the CAR T cells correlated with clinical responses, and CAR T cells have persisted and remain functional beyond 4 years in the first two patients achieving CR; no patient in CR has relapsed. All responding patients have developed B cell aplasia and experienced cytokine release syndrome, coincident with T cell proliferation. Minimal residual disease is not detectable in patients who achieved CR, suggesting that disease eradication may be possible in some patients with advanced CLL. In separate studies we have asked whether the same CD19 CAR may have activity in tumors that do not express CD19. A patient with refractory multiple myeloma was treated with CTL019 cells, a cellular therapy consisting of autologous T cells transduced with an anti-CD19 chimeric antigen receptor, following myeloablative chemotherapy (melphalan 140 mg/m2) and autologous stem cell transplantation (2). Four years earlier, autologous transplantation with a higher melphalan dose (200 mg/m2) had induced only a partial, transient response. Autologous transplantation followed by CTL019 cells led to a complete response with no evidence of progression and no measurable serum or urine monoclonal protein at last evaluation, 12 months after treatment. This response was achieved despite absence of CD19 expression in 99.95% of this patient's neoplastic plasma cells.

Lymphocyte Recovery Kinetics in Patients Undergoing Myeloablative Conditioning and Allogeneic Stem Cell Transplantation

Immune reconstitution following stem cell transplantation (SCT) may be considered as a dynamical system in which future events are predicated on all the preceding past events. In turn, lymphoid reconstitution over time will determine the clinical trajectory an individual patient might take. Lymphoid recovery following myeloablative stem cell transplantation (SCT) displays a logistic (sigmoidal) pattern of exponential growth followed by a plateau. This study aims to understand whether logistic modeling of lymphocyte recovery following SCT can be used to predict outcomes and thus guide therapies to minimize the competing pathologies of graft vs. host disease (GVHD) and relapse. A retrospective analysis of allogeneic SCT performed from 2008 to 2011 was undertaken to compare lymphoid recovery and clinical outcomes in 82 patients with acute myelogenous leukemia, acute lymphocytic leukemia and myelodysplastic syndromes. Using Prism software, a logistic curve was successfully fitted to the absolute lymphocyte count recovery in all patients. Patients were classified according to the magnitude and rate of lymphoid recovery; Type A achieved an absolute lymphocyte count (ALC) of > 1000/mcrL by day 45; Type B an ALC 500 <x < 1000 /mcrL and Type C, an ALC <500/mcrL. There was a significant difference in overall survival (Kaplan-Meier p=0.002) and one-year survival whereby 32/45 (71%) of Type A, 15/26 (58%) of Type B and 2/11 (18%) of Type C remained alive (p=.006). There was no difference in cGVHD (p=0.22) or relapse (p=0.52) incidence between patients with patterns A and B; all patients with pattern C experienced death, relapse or cGVHD within one year. Acute Lymphoblastic Leukemia as initial diagnosis (p=0.04), unrelated donor (p=0.007), mycophenolate mofetil GVHD prophylaxis (p=0.04) predicted type C pattern. Within this logistic framework, cellular recovery is characterized by the parameters R (slope of ascent), a (time of maximal ascent) and K ( plateau), the 'steady state' lymphocyte count. Mean K was significantly different between pattern type whereby pattern A had mean ALC of 1760 /mcrL, pattern B an ALC of 868 and pattern C, an ALC of 262 (p=0.0029) respectively. Neither parameters, a nor R were significantly different between pattern types. CMV, acute GVHD and relapse all were associated with deviation from logistic behavior. Weaning of tacrolimus post-transplant was associated with a second, separate phase of logistic expansion of ALC in some patients. Low K or steady state lymphocyte count is a risk factor for relapse and early death. Pattern B have no increased risk of GVHD compared to Pattern A. Assesing lymphoid reconstitution as a logistic function of time allows dynamic association of donor immune recovery with clinical outcomes and may allow for preemptive adjustments in immune suppresssion or use donor lymphocyte infusions to optimize clinical outcomes. [Display omitted] [Display omitted] DisclosuresNeale:CHRB: Research Funding.

Influence of Fludarabine Pharmacokinetics on Outcome of Allogeneic Stem Cell Transplantation with Fludarabine-Busulfan Conditioning

Introduction Precise targeting of Busulfan dose has resulted in improved transplant outcomes following myeloablative conditioning with Fludarabine plus Busulfan (Flu-Bu). However, the impact of Fludarabine pharmacokinetics on outcomes in allogeneic stem cell transplantation (SCT) following myeloablative conditioning remains undefined.Methods A retrospective single-centre analysis was performed to evaluate the clinical outcomes of 88 patients who received Flu-Bu based conditioning. Patients received Flu (50mg/m2 days-6 to -2), Bu (3.2mg/kg days-5 to -2), and Total Body Irradiation (400 cGy in two doses on day-1). Busulfan dosing was adjusted to achieve a total exposure of 3750 μmol·min/L. Levels of the Fludarabine metabolite 9βD-arabinofuranosyl-2-fluoroadenosine were determined by high performance liquid chromatography-tandem mass spectrometry. Fludarabine exposure, expressed as Fludarabine area under the concentration-time curve (AUC), was calculated on patient blood samples collected on day-5.Results Median age of the 88 patients was 49 (range 18-65) years, and median creatinine clearance was 120.5mL/min (range 48-305mL/min). The most common transplanted hematologic malignancies included AML (31%), ALL (20%), and MDS (10%). 32 (36%) received their transplants from HLA-compatible siblings, and 56 (64%) from unrelated donors. Median plasma AUC was 9.038μg·h/mL (range 2.429 - 66.655μg·h/mL). When comparing patients with lower Flu exposure <9.000μg·h/mL versus those with higher Flu exposure >9.000μg·h/mL, there was no significant difference in grade II-IV acute Graft versus Host Disease (aGvHD; 25% versus 32%, p=0.27) or grade III-IV aGvHD (11% versus 14%, p=0.52). Furthermore, there was no difference in average days to engraftment (13.8 versus 13.9, 95% CI 13.01 - 14.72, p=0.77), or average number of infections in 1-year post transplant (2.3 versus 2.5, 95% CI 1.68 - 3.30, p=0.68). Transplant related mortality (TRM) at 100 days was not improved (7.0% versus 11.4%, p= 0.52) with AUC <9.000μg·h/mL. Progression free survival at 3 years with lower Flu exposure <9.000μg·h/mL was 68% (95%CI 53 - 79) compared to higher Flu exposure >9.000μg·h/mL at 59% (95% CI 45-73, p=0.70). Finally, there was no difference in overall survival (OS) at 12 months (Figure 1.0) in patients with an AUC <9.000μg·h/mL (73%, 95% CI 57-83) versus those with AUC >9.000μg·h/mL (73%, 95% CI 55-83, p-value 0.99).Conclusion In the setting of normal renal function, we have demonstrated that Fludarabine pharmacokinetics does not effect clinical outcomes in myeloablative allogeneic SCT. These data support no role for therapeutic dose monitoring and dose adjustment with Fludarabine in myeloablative conditioning regiments. [Display omitted] DisclosuresOff Label Use: Fludarabine in the use of myeloablative conditioning for allogeneic stem cell transplantation..

Guidelines for the diagnosis and management of adult aplastic anaemia.

Sally B. Killick (Writing Group Chair), Nick Bown, Jamie Cavenagh, Inderjeet Dokal, Theodora Foukaneli, Peter Hillmen, Robin Ireland, Austin Kulasekararaj, Ghulam Mufti, John A Snowden, Sujith Samarasinghe, Anna Wood (BCSH Task Force Member), Judith C.W. Marsh on behalf of the British Society for Standards in Haematology. The Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Bournemouth, Northern Genetics Service, Newcastle upon Tyne, St Bartholomew’s Hospital, Barts Health NHS Trust, London, Barts and The London School of Medicine and Dentistry, Queen Mary University of London and Barts Health NHS Trust, London, Addenbrooks Hospital, University of Cambridge, Cambridge, Leeds Teaching Hospitals, Leeds, Kings College Hospital NHS Foundation Trust, London, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield Great Ormond Street Hospital for Children NHS Foundation Trust, London, West Hertfordshire NHS Trust, Watford.

移植後シクロホスファミドを用いたHLA半合致移植の現状と課題

Recent studies demonstrated that donor engraftment was achieved without severe graft-versus-host disease (GVHD) after posttransplant cyclophosphamide (PTCy) based human leukocyte antigen (HLA) -haploidentical bone marrow transplantation (PTCy-haploBMT). It has been suggested that PTCy selectively deplete proliferating alloreactive T cells, while preserving regulatory T cells. Although GVHD and non-relaplse mortality appears to be low, relapse remains a major problem after PTCy-haploBMT. Recently, PTCy is increasingly used in the setting of peripheral blood stem cell transplantation or myeloablative stem cell transplantation in order to reduce rejection and disease relapse. Furthermore, this strategy can be applied to patients with nonmalignant disorders. This strategy also represents a promising platform to establish calcineurin-inhibitor free GVHD prophylaxis in HLA-identical stem cell transplantation.