Hematocrit control and thrombotic risk in patients with polycythemia vera treated with ruxolitinib in clinical practice.

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by unregulated red blood cell production resulting in elevated hemoglobin and/or hematocrit levels. Patients often have symptoms such as fatigue, pruritus, and painful splenomegaly, but are also at risk of thrombosis, both venous and arterial. Ruxolitinib, a selective Janus kinase inhibitor, is approved by the US Food and Drug Administration as second-line cytoreductive treatment after intolerance or inadequate response to hydroxyurea. Although ruxolitinib has been widely used in this setting, limited data exist in the literature on ruxolitinib treatment patterns and outcomes among patients with PV in routine clinical practice. We report a retrospective, observational, cohort study of patients treated for PV with ruxolitinib across three US centers (academic and regional practice) from December 2014-December 2019. The study included 69 patients, with a median follow-up duration of 3.7 years (95% CI, 2.9-4.4). Our data demonstrate very high rates of hematocrit control (88% of patients by three months and 89% by six months); few patients required dose adjustments or suspension. No arterial thromboses were observed; however, the follow-up duration does not allow for the generation of meaningful conclusions from this. Three patients had thrombotic events; one was in the setting of a second malignancy, one post-operative, and a third related to prolonged immobility. We also found that 28% of patients initiated ruxolitinib as a result of poorly controlled platelet counts, second only to hydroxyurea intolerance (46%) as a reason to start therapy. In clinical practice, ruxolitinib continues to be effective in controlling hematocrit levels after three and six months of treatment in patients and is associated with low thrombotic risk.

Association between elevated white blood cell counts and thrombotic events in polycythemia vera: analysis from REVEAL.

ABSTRACT: Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by clonal proliferation of hematopoietic progenitor cells and is associated with an increased risk of thrombotic events (TEs). Established risk factors for TEs in patients with PV include advanced age, TE history, and elevated hematocrit. Although an association of TE with elevated white blood cell (WBC) counts has been suggested by retrospective studies, this relationship needs further validation. The prospective observational study of patients with polycythemia vera in US clinical practices (REVEAL) study collected prospective clinical data from 2510 patients with PV with a median follow-up of 44.7 months (range, 2-59 months) from enrollment. Using time-dependent covariate Cox proportional hazards models, blood counts were individually modeled with sex, age, disease duration, TE history at enrollment (baseline covariates), and treatment (time-dependent covariate). Analysis of 2271 participants identified 142 TEs in 106 patients. Significant associations with initial TE occurrence during the study period were observed for hematocrit level >45% (hazard ratio [HR], 1.84; 95% confidence interval [95% CI], 1.234-2.749; P = .0028) and WBCs >11 × 109/L (HR, 2.35; 95% CI, 1.598-3.465; P < .0001). Elevated WBC count was significantly associated with initial TE occurrence in both low-risk and high-risk PV. When hematocrit was controlled at ≤45%, WBC count >12 × 109/L was significantly associated with TE occurrence (HR, 1.95; 95% CI, 1.066-3.554; P = .0300). The results support incorporation of WBC count into PV risk stratification and studies of treatment strategies, and indicate the importance of controlling both hematocrit and WBC count in disease management. This trial was registered at www.clinicaltrials.gov as #NCT02252159.

Pharmacogenetic and clinical predictors of voriconazole concentration in hematopoietic stem cell transplant recipients receiving CYP2C19-guided dosing.

CYP2C19-guided voriconazole dosing reduces pharmacokinetic variability, but many patients remain subtherapeutic. The aim of this study was to evaluate the effect of candidate genes and a novel CYP2C haplotype on voriconazole trough concentrations in patients receiving CYP2C19-guided dosing. This is a retrospective candidate gene study in allogeneic hematopoietic cell transplant (HCT) patients receiving CYP2C19-guided voriconazole dosing. Patients were genotyped for ABCB1, ABCG2, CYP2C9, CYP3A4, CYP3A5, and the CYP2C haplotype. Of 185 patients, 36% were subtherapeutic (of which 79% were normal or intermediate metabolizers). In all patients, CYP2C19 (p < 0.001), age (p = 0.018), and letermovir use (p = 0.001) were associated with voriconazole concentrations. In the subset receiving 200 mg daily (non-RM/UMs), CYP2C19 (p = 0.004) and ABCG2 (p = 0.015) were associated with voriconazole concentrations; CYP2C19 (p = 0.028) and letermovir use (p = 0.001) were associated with subtherapeutic status. CYP2C19 phenotype and letermovir use were significantly associated with subtherapeutic voriconazole concentrations and may be used to improve voriconazole precision dosing, while further research is needed to clarify the role of ABCG2 in voriconazole dosing.

Evaluation of pentamidine tolerability and efficacy between CYP2C19 phenotypes.

Intravenous pentamidine is used for prophylaxis against Pneumocystis jirovecii pneumonia, an infection seen in hematopoietic stem cell transplant recipients. Pentamidine is partially metabolized by CYP2C19, which is vulnerable to pharmacogenetic variation. This retrospective study evaluated allogeneic hematopoietic stem cell transplant patients who received intravenous pentamidine as P. jirovecii pneumonia prophylaxis. The primary objective was the association between CYP2C19 phenotype and discontinuation of pentamidine due to drug-related side effects based on univariate logistic regression (N = 81). Ten patients (12.3%) discontinued pentamidine because of side effects. There was no difference in discontinuation between phenotype groups (p = 0.18) or discontinuation due to side effects (p = 0.76). Overall, no association was seen between phenotypes and pentamidine-related side effects (p = 0.475). Drug discontinuation rates and P. jirovecii pneumonia infection rates were low.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis.

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

Top advances of the year: Myeloproliferative neoplasms.

The rapid pace of drug development in hematology has led to multiple approvals for myelofibrosis (MF) and polycythemia vera (PV) in recent years. Moreover, there are many innovative agents and combinations being explored for myeloproliferative neoplasms (MPNs). In the past year, there have been several advances in MF, PV, and essential thrombocythemia. In MF, investigational approaches are focusing on strategies to optimize inhibition of signal transduction (including JAK inhibition), modify epigenetics, enhance apoptosis, target DNA replication, transform host immunity, and/or alter the tumor microenvironment. In PV, ropeginterferon alfa-2b has been introduced to the market in the United States, and data continue to accumulate to support the safety and efficacy of this treatment. Hepcidin mimesis is also emerging as a novel way to treat erythrocytosis. In essential thrombocythemia, ropeginterferon alfa-2b is being evaluated, as are therapies to modify epigenetics and inhibit CALR. The enhanced focus on MPNs brings hope that our field can improve morbidity and mortality in this group of diseases.

Standardising acute myeloid leukaemia classification systems: a perspective from a panel of international experts.

The existence of two acute myeloid leukaemia classification systems-one put forth by WHO and one by the International Consensus Classification in 2022-is concerning. Although both systems appropriately move towards genomic disease definitions and reduced emphasis on blast enumeration, there are consequential disagreements between the two systems on what constitutes a diagnosis of acute myeloid leukaemia. This fundamental problem threatens the ability of heath-care providers to diagnose acute myeloid leukaemia, communicate with patients and other health-care providers, and deliver appropriate and consistent management strategies for patients with the condition. Clinical trial eligibility, standardised response assessments, and eventual drug development and regulatory pathways might also be negatively affected by the discrepancies. In this Viewpoint, we review the merits and limitations of both classification systems and illustrate how the coexistence, as well as application of both systems is an undue challenge to patients, clinicians, hematopathologists, sponsors of research, and regulators. Lastly, we emphasise the urgency and propose a roadmap, by which the two divergent classification systems can be harmonised.

Haploidentical donor hematopoietic cell transplantation for myelodysplastic/myeloproliferative overlap neoplasms: results from a North American collaboration.

Haploidentical donors offer a potentially readily available donor, especially for non-White patients, for hematopoietic cell transplantation (HCT). In this North American collaboration, we retrospectively analyzed outcomes of first HCT using haploidentical donor and post-transplantation cyclophosphamide (PTCy) in myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) overlap neoplasms (MDS/MPN). We included 120 consecutive patients who underwent HCT using a haploidentical donor for MDS/MPN across 15 centers. Median age was 62.5 years and 38% were of non-White/Caucasian ethnicity. The median follow-up was 2.4 years. Graft failure was reported in seven of 120 (6%) patients. At 3 years, nonrelapse mortality (NRM) was 25% (95% confidence interval [CI]: 17-34), relapse 27% (95% CI: 18-36), grade 3-4 acute graftversus- host disease 12% (95% CI: 6-18), chronic graft-versus-host disease requiring systemic immunosuppression 14% (95% CI: 7-20), progression-free survival (PFS) 48% (95% CI: 39-59), and overall survival (OS) 56% (95% CI: 47-67). On multivariable analysis, NRM was statistically significantly associated with advancing age at HCT (per decade increment, subdistribution hazard ratio [sdHR] =3.28; 95% CI: 1.30-8.25); relapse with the presence of mutation in EZH2/RUNX1/SETBP1 (sdHR=2.61; 95% CI: 1.06-6.44); PFS with advancing age at HCT (per decade increment, HR=1.98, 95% CI: 1.13-3.45); and OS with advancing age at HCT (per decade increment, HR=2.01; 95% CI: 1.11-3.63) and splenomegaly at HCT/prior splenectomy (HR=2.20; 95% CI: 1.04-4.65). Haploidentical donors are a viable option for HCT in MDS/MPN, especially for those disproportionately represented in the unrelated donor registry. Hence, donor mismatch should not preclude HCT for patients with MDS/MPN, an otherwise incurable malignancy. In addition to patient age, disease-related factors including splenomegaly and high-risk mutations dominate outcomes following HCT.

Temperature-Responsive Nanoporous Membranes from Self-Assembly of Poly(N-isopropylacrylamide) Hairy Nanoparticles.

Nanoporous membranes play a critical role in numerous separations on laboratory and industrial scales, ranging from water treatment to biotechnology. However, few strategies exist that allow for the preparation of mechanically robust nanoporous membranes whose separation properties can be easily tuned. Here, we introduce a new family of tunable nanoporous membranes based on nanoparticles decorated with temperature-responsive polymer brushes. We prepared mechanically robust membranes from hairy nanoparticles (HNPs) carrying PNIPAM polymer brushes. We assembled the HNPs into thin films through pressure-driven deposition of nanoparticle suspensions and measured the permeability and filtration cutoff of these membranes at different temperatures. The membrane pore diameter at room temperature varied between 10 and 30 nm depending on the polymer length. The water permeability of these membranes could be controlled by temperature, with the effective pore diameter increasing by a factor of 3-6 (up to 100 nm) when the temperature was increased to 60 °C. The size selectivity of these membranes in the filtration of nanoparticles could also be attenuated by temperature. Molecular dynamics computer simulations of a coarse-grained HNP model show that temperature-sensitive pores sizes are consistent with our experimental results and reveal the polymer configurations responsible for the observed filtration membrane permeability. We expect that these membranes will be useful for separations and in the preparation of responsive microfluidic devices.

A simple prognostic system in patients with myelofibrosis undergoing allogeneic stem cell transplantation: a CIBMTR/EBMT analysis.

To develop a prognostic model for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) for myelofibrosis (MF), we examined the data of 623 patients undergoing allo-HCT between 2000 and 2016 in the United States (the Center for International Blood and Marrow Transplant Research [CIBMTR] cohort). A Cox multivariable model was used to identify factors prognostic of mortality. A weighted score using these factors was assigned to patients who received transplantation in Europe (the European Bone Marrow Transplant [EBMT] cohort; n = 623). Patient age >50 years (hazard ratio [HR], 1.39; 95% confidence interval [CI], 0.98-1.96), and HLA-matched unrelated donor (HR, 1.29; 95% CI, 0.98-1.7) were associated with an increased hazard of death and were assigned 1 point. Hemoglobin levels <100 g/L at time of transplantation (HR, 1.63; 95% CI, 1.2-2.19) and a mismatched unrelated donor (HR, 1.78; 95% CI, 1.25-2.52) were assigned 2 points. The 3-year overall survival (OS) in patients with a low (1-2 points), intermediate (3-4 points), and high score (5 points) were 69% (95% CI, 61-76), 51% (95% CI, 46-56.4), and 34% (95% CI, 21-49), respectively (P < .001). Increasing score was predictive of increased transplant-related mortality (TRM; P = .0017) but not of relapse (P = .12). The derived score was predictive of OS (P < .001) and TRM (P = .002) but not of relapse (P = .17) in the EBMT cohort as well. The proposed system was prognostic of survival in 2 large cohorts, CIBMTR and EBMT, and can easily be applied by clinicians consulting patients with MF about the transplantation outcomes.

COVID-19 vaccine uptake trends in SARS-CoV-2 previously infected cancer patients.

Purpose: Cancer patients are at high risk of developing severe illness from SARS-CoV-2 infection, but risk is lowered with receipt of COVID-19 vaccine. COVID-19 vaccination uptake among previously infected cancer patients may be influenced by an assumption of natural immunity, predicted weak immune response, or concerns about vaccine safety. The objective of this study was to evaluate COVID-19 vaccine uptake trends in cancer patients previously infected with SARS-CoV-2. Materials and Methods: Medical records of 579 sequential cancer patients undergoing active treatment at Levine Cancer Institute who tested positive for COVID-19 between January 2020 and January 2021 were evaluated. Patients who died prior to vaccine eligibility were excluded from the analysis. Demographic, clinical, and COVID-19 related characteristics were analyzed to identify prognostic factors for COVID-19 vaccine uptake as this information could be important for health policy design for future pandemics. Results: Eighty-one patients died prior to the availability of COVID-19 vaccines. The acceptance rate of COVID-19 vaccination among 498 previously infected cancer patients was 54.6%. Of the patients with known vaccination dates, 76.8% received their first vaccine by April 17th, 2021. As of November 30, 2021, 23.7.% of eligible patients were boosted. In univariate models, older age, female sex, higher income, solid tumor cancer type, and hormone therapy were significantly associated with higher vaccine uptake, while Hispanic/Latino ethnicity was significantly associated with lower vaccine uptake. In a multivariable model, age (OR 1.18, 95% CI 1.10-1.28; p < 0.001), female sex (OR 1.80, 95% CI 1.22-2.66; p = 0.003), and higher income (OR 1.11, 95% CI 1.01-1.22; p = 0.032), were predictive of COVID-19 vaccine uptake. Conclusions: Overall, vaccine uptake was low among our cohort of previously infected cancer patients. Older age, female sex, and higher income were the only variables associated with COVID-19 vaccine uptake within this vulnerable patient population.

Haploidentical Donor Blood or Marrow Transplantation for Myelodysplastic/Myeloproliferative Overlap Neoplasms: Results from a North American Collaboration.

Haploidentical donors offer a potentially readily available donor, especially for non-White patients, for blood or marrow transplantation (BMT). In this collaboration across North America, we retrospectively analyzed outcomes of first BMT using haploidentical donor and posttransplantation cyclophosphamide (PTCy) in MDS/MPN-overlap neoplasms (MDS/MPN), an otherwise incurable hematological neoplasm. We included 120 patients, 38% of non-White/Caucasian ethnicity, across 15 centers with median age at BMT 62.5 years. The median follow-up is 2.4 years. Graft failure was reported in 6% patients. At 3-years, nonrelapse mortality (NRM) was 25%, relapse 27%, grade 3-4 acute graft versus host disease (GVHD) 12%, chronic GVHD requiring systemic immunosuppression 14%, progression-free survival (PFS) 48% and overall survival (OS) 56%. On multivariable analysis, statistically significant associations included older age at BMT (per decade increment) with NRM (sdHR 3.28, 95%CI 1.30-8.25), PFS (HR 1.98, 95% 1.13-3.45) and OS (HR 2.01, 95% CI 1.11-3.63), presence of mutation in EZH2/RUNX1/SETBP1 with relapse (sdHR 2.61, 95%CI 1.06-6.44), and splenomegaly at BMT/prior splenectomy with OS (HR 2.20, 95%CI 1.04-4.65). Haploidentical donors are a viable option for BMT in MDS/MPN, especially for those disproportionately represented in the unrelated donor registry. Disease-related factors including splenomegaly and high-risk mutations dominate outcomes following BMT.

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

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

Remembering the Work of Phillip L. Geissler: A Coda to His Scientific Trajectory.

Phillip L. Geissler made important contributions to the statistical mechanics of biological polymers, heterogeneous materials, and chemical dynamics in aqueous environments. He devised analytical and computational methods that revealed the underlying organization of complex systems at the frontiers of biology, chemistry, and materials science. In this retrospective we celebrate his work at these frontiers.

First-in-human study of JNJ-63709178, a CD123/CD3 targeting antibody, in relapsed/refractory acute myeloid leukemia.

This study aimed to identify a recommended phase II dose and evaluate the safety, tolerability, pharmacokinetics/pharmacodynamics, and preliminary clinical activity of JNJ-63709178, a CD123/CD3 dual-targeting antibody, in patients with relapsed or refractory acute myeloid leukemia. Intravenous (i.v.) and subcutaneous (s.c.) administration of JNJ-63709178 were evaluated. The i.v. infusions were administered once every 2 weeks (cohorts 1-5 [n = 17]) or twice weekly (cohorts 6-11 [n = 36]). A twice-weekly s.c. dosing regimen with step-up dosing was also studied (s.c. cohorts 1-2 [n = 9]). Treatment-emergent adverse events (TEAEs) greater than or equal to grade 3 were observed in 11 (65%) patients in cohorts 1-5 and 33 (92%) patients in cohorts 6-11. At the highest i.v. dose (4.8 µg/kg), 5 (71%) patients discontinued treatment due to TEAEs. For s.c. administration (n = 9), eight (89%) patients experienced TEAEs greater than or equal to grade 3 and injection site reactions (≤ grade 3) emerged in all patients. At 4.8 µg/kg (i.v. and s.c.), the mean maximum serum concentrations were 30.3 and 3.59 ng/ml, respectively. Increases in multiple cytokines were observed following i.v. and s.c. administrations, and step-up dosing strategies did not mitigate cytokine production or improve the safety profile and led to limited duration of treatment. Minimal clinical activity was observed across all cohorts. The i.v. and s.c. dosing of JNJ-63709178 was associated with suboptimal drug exposure, unfavorable safety profiles, limited clinical activity, and inability to identify a recommended phase II dose.

Impact of pre-transplant induction and consolidation cycles on AML allogeneic transplant outcomes: a CIBMTR analysis in 3113 AML patients.

We investigated the impact of the number of induction/consolidation cycles on outcomes of 3113 adult AML patients who received allogeneic hematopoietic cell transplantation (allo-HCT) between 2008 and 2019. Patients received allo-HCT using myeloablative (MAC) or reduced-intensity (RIC) conditioning in first complete remission (CR) or with primary induction failure (PIF). Patients who received MAC allo-HCT in CR after 1 induction cycle had 1.3-fold better overall survival (OS) than 2 cycles to CR and 1.47-fold better than ≥3 cycles. OS after CR in 2 or ≥3 cycles was similar. Relapse risk was 1.65-fold greater in patients receiving ≥3 cycles to achieve CR. After RIC allo-HCT, the number of induction cycles to CR did not affect OS. Compared to CR in 1 cycle, relapse risk was 1.24-1.41-fold greater in patients receiving 2 or ≥3 cycles. For patients receiving only 1 cycle to CR, consolidation therapy prior to MAC allo-HCT was associated with improved OS vs. no consolidation therapy. Detectable MRD at the time of MAC allo-HCT did not impact outcomes while detectable MRD preceding RIC allo-HCT was associated with an increased risk of relapse. For allo-HCT in PIF, OS was significantly worse than allo-HCT in CR after 1-3 cycles.

A Phase I Trial of SYK Inhibition with Fostamatinib in the Prevention and Treatment of Chronic Graft-Versus-Host Disease.

Despite the exciting advancement of novel therapies, chronic graft-versus-host disease (cGVHD) remains the most common cause of non-relapse mortality after allogeneic hematopoietic stem cell transplantation (HCT). Frontline treatment of cGVHD involves systemic steroids, which are associated with significant morbidities. We previously found that inhibition of spleen tyrosine kinase (SYK) with fostamatinib preferentially eradicated aberrantly activated B cells in both ex vivo studies of cGVHD patient B cells, as well as in vivo mouse studies. These and other preclinical studies implicated hyper-reactive B-cell receptor signaling and increased SYK expression in the pathogenesis of cGVHD and compelled this first in-human allogeneic HCT clinical trial. We investigated the safety and efficacy of the oral SYK inhibitor, fostamatinib, for both the prevention and treatment of cGVHD. The primary objective was to evaluate the safety of fostamatinib and determine its maximum tolerated dose in the post-HCT setting. Secondary objectives included assessing the efficacy of fostamatinib in preventing and treating cGVHD, as well as examining alterations in B-cell compartments with treatment. This was a single-institution phase I clinical trial that evaluated the use of fostamatinib in allogeneic HCT patients before the development of cGVHD or at the time of steroid-refractory cGVHD (SR-cGVHD). Patients received fostamatinib at one of three dose levels using a continual reassessment algorithm to determine the maximum tolerated dose. Multiparameter flow cytometry was used to evaluate changes in B cell subpopulations over the first year of treatment with fostamatinib. Nineteen patients were enrolled in this phase I trial, with 5 in the prophylaxis arm and 14 in the therapeutic arm. One patient (5%) required discontinuation of therapy for a dose-limiting toxicity. At a median follow-up of over 3 years, no patients had cancer relapse while on fostamatinib treatment, and recurrent malignancy was observed in 1 patient 2 years after the end of therapy. In the prophylaxis arm, 1 of 5 patients (20%) developed cGVHD while on fostamatinib. In the therapeutic arm, the overall response rate was 77%, with a complete response rate of 31%. The median duration of response was 19.3 months and the 12-month failure-free survival was 69% (95% confidence interval, 48-100). Patients were able to reduce their steroid dose by a median of 80%, with 73% remaining on a lower dose at 1 year compared to baseline. There was an early reduction in the proportion of IgD-CD38hi plasmablast-like cells with fostamatinib treatment, particularly in those SR-cGVHD patients who had an eventual response. B-cell reconstitution was not significantly impacted by fostamatinib therapy after allogeneic HCT. Fostamatinib featured a favorable safety profile in the post-HCT setting. Our data suggests an early efficacy signal that was associated with effects on expected cell targets in both the prophylaxis and treatment of cGVHD, providing rationale for a phase II investigation.

The mutational landscape in chronic myelomonocytic leukemia and its impact on allogeneic hematopoietic cell transplantation outcomes: a Center for Blood and Marrow Transplantation Research (CIBMTR) analysis.

Somatic mutations are recognized as an important prognostic factor in chronic myelomonocytic leukemia (CMML). However, limited data are available regarding their impact on outcomes after allogeneic hematopoietic cell transplantation (HCT). In this registry analysis conducted in collaboration with the Center for International Blood and Marrow Transplantation Registry database/sample repository, we identified 313 adult patients with CMML (median age: 64 years, range, 28- 77) who underwent allogeneic HCT during 2001-2017 and had an available biospecimen in the form of a peripheral blood sample obtained prior to the start of conditioning. In multivariate analysis, a CMML-specific prognostic scoring system (CPSS) score of intermediate-2 (HR=1.46, P=0.049) or high (HR=3.22, P=0.0004) correlated significantly with overall survival. When the molecularly informed CPSS-Mol prognostic model was applied, a high CPSS-Mol score (HR=2 P=0.0079) correlated significantly with overall survival. The most common somatic mutations were in ASXL1 (62%), TET2 (35%), KRAS/NRAS (33% combined), and SRSF2 (31%). DNMT3A and TP53 mutations were associated with decreased overall survival (HR=1.70 [95% CI: 1.11-2.60], P=0.0147 and HR=2.72 [95% CI: 1.37-5.39], P=0.0042, respectively) while DNMT3A, JAK2, and TP53 mutations were associated with decreased disease-free survival (HR=1.66 [95% CI: 1.11-2.49], P=0.0138, HR=1.79 [95% CI: 1.06-3.03], P=0.0293, and HR=2.94 [95% CI: 1.50-5.79], P=0.0018, respectively). The only mutation associated with increased relapse was TP53 (HR=2.94, P=0.0201). Nonetheless, the impact of TP53 mutations specifically should be interpreted cautiously given their rarity in CMML. We calculated the goodness of fit measured by Harrell's C-index for both the CPSS and CPSS-Mol, which were very similar. In summary, via registry data we have determined the mutational landscape in patients with CMML who underwent allogeneic HCT, and demonstrated an association between CPSS-Mol and transplant outcomes although without major improvement in the risk prediction beyond that provided by the CPSS.