Long-term outcome after allogeneic hematopoietic cell transplantation for myelofibrosis

Anti-T-lymphocyte globulin improves GvHD-free and relapse-free survival in myelofibrosis after matched related or unrelated donor transplantation

Acute and chronic graft-versus-host disease (GvHD) are major complications of allogeneic hematopoietic cell transplantation (alloHCT). In vivo T-cell depletion with anti-T-lymphocyte globulin (ATLG) as part of the conditioning regimen prior to alloHCT is frequently used as GvHD prophylaxis, but data on its role in myelofibrosis is scarce. We took advantage of an international collaborative network to investigate the impact of ATLG in myelofibrosis undergoing first alloHCT. We included 707 patients (n = 469 ATLG and n = 238 non-ATLG prophylaxis). The cumulative incidence of acute GvHD grade II-IV was 30% for the ATLG group vs. 56% for the non-ATLG group (P < 0.001). Acute GvHD grade III-IV occurred in 20% vs. 25%, respectively (P = 0.01). Incidence of mild-to-severe chronic GvHD was 49% vs. 50% (P = 0.52), while ATLG showed significantly lower rates of severe chronic GvHD (7% vs. 18%; P = 0.04). GvHD-free and relapse-free survival (GRFS) at 6 years was 45% for the ATLG group vs. 37% for the non-ATLG group (P = 0.02), driven by significantly improved GRFS of ATLG in matched related and matched unrelated donors. No significant differences in risk for relapse, non-relapse mortality, and overall survival were observed. Multivariable modeling for GRFS showed a 48% reduced risk of GvHD, relapse, or death when using ATLG.

Graft-versus-host disease and impact on relapse in myelofibrosis undergoing hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (alloHSCT) remains the only curative treatment for myelofibrosis (MF). Relapse occurs in 10-30% and remains a major factor for dismal outcomes. Previous work suggested that graft-versus-host disease (GVHD) might be associated with risk of relapse. This study included 341 patients undergoing their first (n = 308) or second (n = 33) alloHSCT. Anti-T-lymphocyte or antithymocyte globulin was used for GVHD prophylaxis in almost all patients. Median time to neutrophile and platelet engraftment was 13 days and 19 days, respectively. The cumulative incidence of acute GVHD grade II-IV was 41% (median, 31 days; range, 7-112). Grade III-IV acute GVHD was observed in 22%. The cumulative incidence of chronic GVHD was 61%. Liver was affected in 23% of acute GVHD cases and 46% of chronic GVHD cases. Severe acute GVHD was associated with high non-relapse mortality. The development of acute GVHD grade II and moderate GVHD was an independent factor for reduced risk for relapse after transplantation without increased risk for non-relapse mortality, while especially acute GVHD grade IV was associated with high non-relapse mortality. Last, we identified that ongoing response to ruxolitinib, accelerated-phase MF at time of transplantation and splenectomy prior to transplantation were independent predictors for relapse.

Allogeneic hematopoietic stem cell transplantation in patients aged 60-79 years in Germany (1998-2018): a registry study

Incidences of diseases treated with transplantation frequently peak at higher age. The contribution of age to total risk of transplantation has not been estimated amidst an aging society. We compare outcomes of 1,547 patients aged 70-79 years and 9,422 patients aged 60-69 years transplanted 1998-2018 for myeloid, lymphoid and further neoplasia in Germany. To quantify the contribution of population mortality to survival, we derive excess mortality based on a sex-, year- and agematched German population in a multistate model that incorporates relapse and graft-versus-host-disease (GvHD). Overall survival, relapse-free survival (RFS) and GvHD-free-relapse-free survival (GRFS) is inferior in patients aged 70-79 years, compared to patients aged 60-69 years, with 36% (95% Confidence Interval [CI]: 34-39%) versus 43% (41-44%), 32% (30- 35%) versus 36% (35-37%) and 23% (21-26%) versus 27% (26-28%) three years post-transplant (P<0.001). Cumulative incidences of relapse at three years are 27% (25-30%) for patients aged 70-79 versus 29% (29-30%) (60-69 years) (P=0.71), yet the difference in non-relapse mortality (NRM) (40% [38-43%] vs. 35% [34-36%] in patients aged 70-79 vs. 60-69 years) (P<0.001) translates into survival differences. Median OS of patients surviving >1 year relapse-free is 6.7 (median, 95% CI: 4.5-9.4, 70-79 years) versus 9 (8.4-10.1, 60-69 years) years since landmark. Three years after RFS of one year, excess NRM is 14% (95% CI: 12-18%) in patients aged 70-79 versus 12% [11-13%] in patients aged 60-69, while population NRM is 7% (6-7%) versus 3% (3-3%). Mortality for reasons other than relapse, GvHD, or age is as high as 27% (24-29%) and 22% (22-23%) four years after transplantation. In conclusion, survival amongst older patients is adequate after allogeneic stem cell transplantation.

Are transplant indications changing for myelofibrosis?

Myelofibrosis is a devastating myeloid malignancy characterized by dysregulation of the JAK-STAT pathway, resulting in splenomegaly, constitutional symptoms, anemia, thrombocytopenia, leukocytosis, and an increased likelihood of progression to acute leukemia. The only curative option is allogeneic stem cell transplantation. The numbers of transplants have been increasing every year, and although there have been improvements in survival, there remain many unanswered questions. In this review, we will evaluate patient selection and appropriate timing for transplantation. We will cover the current prognostic scoring systems, which can aid in the decision of when to move forward with transplant. We will also review the different donor options, as well as the conditioning regimens. The peritransplant management of splenomegaly will be reviewed. We will discuss management of posttransplant complications such as loss of donor chimerism or disease relapse. Finally, we will review what is known about the outlook of patients who have undergone allogeneic stem cell transplant with regards to quality of life and long-term survival.

Transplantation Outcomes of Myelofibrosis with Busulfan and Fludarabine Myeloablative Conditioning

Outcomes of myelofibrosis (MF) with allogeneic stem cell transplantation (allo-SCT) have improved over the past decade, related in part to advances in supportive treatments and conditioning regimens. Several factors are known to predict transplantation outcomes. However, most studies lack homogeneity in conditioning regimens used, limiting their ability to assess prognostic factors on transplantation outcomes. We aimed to identify the risk factors that predict transplantation outcomes in patients with MF who underwent matched or mismatched allo-SCT using a uniform myeloablative conditioning regimen consisting of busulfan and fludarabine with tacrolimus and methotrexate-based graft-versus-host disease prophylaxis. This single-center study included patients with MF who underwent allo-SCT with a matched unrelated donor (MUD), matched related donor (MRD), or mismatched unrelated donor (MMUD) and received busulfan and fludarabine conditioning with methotrexate/tacrolimus-based GVHD prophylaxis. Sixty-five patients with MF met the study criteria and were included in our analysis. At a median follow-up of 35.6 months, the 3-year cumulative incidence of relapse (CIR), nonrelapse mortality (NRM), and overall survival (OS) for all study patients were 27%, 20%, and 65%, respectively. In a multivariable analysis for CIR, prior use of JAK inhibitors was significantly associated with a decreased risk of relapse (hazard ratio [HR], .33; 95% confidence interval [CI], .11 to .99; P = .048). For NRM, Hematopoietic Cell Transplantation Comorbidity Index (≥3 versus <3; HR, 10.09; 95% CI, 2.09 to 48.76; P = .004) and donor type (MUD versus MRD: HR, 5.38; 95% CI, 1.14 to 25.30; P = .033; MMUD versus MRD: HR, 10.73; 95% CI, 1.05 to 109.4; P = .045) were associated with an increased risk of mortality. Likewise for OS, HCT-CI (≥3 versus <3; HR, 3.31; 95% CI, 1.22 to 8.99; P = .019) and donor type (MMUD versus MRD: HR, 5.20; 95% CI, 1.35 to 19.98; P = .016) were significantly associated with inferior survival. Longer time from diagnosis to allo-SCT seemed to confer worse survival, but the difference did not reach statistical significance (>12 months versus ≤12 months: NRM: HR, 7.20; 95% CI, .96 to 53.94; P = .055; OS: HR, 2.60; 95% CI, .95 to 7.14; P = .06). In a homogenous cohort of MF patients uniformly treated with busulfan/fludarabine myeloablative conditioning and methotrexate-based GVHD prophylaxis, we show that donor choice and HCT-CI are the 2 strongest predictors for improved survival after allo-SCT.

How I treat transplant-eligible patients with myelofibrosis

Despite the approval of Janus kinase inhibitors and novel agents for patients with myelofibrosis (MF), disease-modifying responses remain limited, and hematopoietic stem cell transplantation (HSCT) remains the only potentially curative treatment option. The number of HSCTs for MF continues to increase worldwide, but its inherent therapy-related morbidity and mortality limit its use for many patients. Furthermore, patients with MF often present at an older age, with cytopenia, splenomegaly, and severe bone marrow fibrosis, posing challenges in managing them throughout the HSCT procedure. Although implementation of molecular analyses enabled improved understanding of disease mechanisms and subsequently sparked development of novel drugs with promising activity, prospective trials in the HSCT setting are often lacking, making an evidence-based decision process particularly difficult. To illustrate how we approach patients with MF with respect to HSCT, we present 3 different clinical scenarios to capture relevant aspects that influence our decision making regarding indication for, or against, HSCT. We describe how we perform HSCT according to different risk categories and, furthermore, discuss our up-to-date approach to reduce transplant-related complications. Last, we show how to harness graft-versus-MF effects, particularly in the posttransplant period to achieve the best possible outcomes for patients.

Application of Fourier Transform InfraRed spectroscopy of machine learning with Support Vector Machine and principal components analysis to detect biochemical changes in dried serum of patients with primary myelofibrosis

Primary myelofibrosis (PM) is a myeloproliferative neoplasm characterized by stem cell-derived clonal neoplasms. Several factors are involved in diagnosing PM, including physical examination, peripheral blood findings, bone marrow morphology, cytogenetics, and molecular markers. Commonly gene mutations are used. Also, these gene mutations exist in other diseases, such as polycythemia vera and essential thrombocythemia. Hence, understanding the molecular mechanism and finding disease-related biomarker characteristics only for PM is crucial for the treatment and survival rate. For this purpose, blood samples of PM (n = 85) vs. healthy controls (n = 45) were collected for biochemical analysis, and, for the first time, Fourier Transform InfraRed (FTIR) spectroscopy measurement of dried PM and healthy patients' blood serum was analyzed. A Support Vector Machine (SVM) model with optimized hyperparameters was constructed using the grid search (GS) method. Then, the FTIR spectra of the biomolecular components of blood serum from PM patients were compared to those from healthy individuals using Principal Components Analysis (PCA). Also, an analysis of the rate of change of FTIR spectra absorption was studied. The results showed that PM patients have higher amounts of phospholipids and proteins and a lower amount of H-O=H vibrations which was visible. The PCA results indicated that it is possible to differentiate between dried blood serum samples collected from PM patients and healthy individuals. The Grid Search Support Vector Machine (GS-SVM) model showed that the prediction accuracy ranged from 0.923 to 1.00 depending on the FTIR range analyzed. Furthermore, it was shown that the ratio between α-helix and β-sheet structures in proteins is 1.5 times higher in PM than in control people. The vibrations associated with the CO bond and the amide III region of proteins showed the highest probability value, indicating that these spectral features were significantly altered in PM patients compared to healthy ones' spectra. The results indicate that the FTIR spectroscope may be used as a technique helpful in PM diagnostics. The study also presents preliminary results from the first prospective clinical validation study.

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.

What is relative survival and what is its role in haematology?

In many haematological diseases, the survival probability is the key outcome. However, when the population of patients is rather old and the follow-up long, a significant proportion of deaths cannot be attributed to the studied disease. This lessens the importance of common survival analysis measures like overall survival and shows the need for other outcome measures requiring more complex methodology. When disease-specific information is of interest but the cause of death is not available in the data, relative survival methodology becomes crucial. The idea of relative survival is to merge the observed data set with the mortality data in the general population and thus allow for an indirect estimation of the burden of the disease. In this work, an overview of different measures that can be of interest in the field of haematology is given. We introduce the crude mortality that reports the probability of dying due to the disease of interest; the net survival that focuses on excess hazard alone and presents the key measure in comparing the disease burden of patients from populations with different general population mortality; and the relative survival ratio which gives a simple comparison of the patients' and the general population survival. We explain the properties of each measure, and some brief notes are given on estimation. Furthermore, we describe how association with covariates can be studied. All the methods and their estimators are illustrated on a sub-cohort of older patients who received a first allogeneic hematopoietic stem cell transplantation for myelodysplastic syndromes or secondary acute myeloid leukemia, to show how different methods can provide different insights into the data.

Impact of Chronic Graft-Versus-Host Disease (GVHD) on Patients' Employment, Income, and Informal Caregiver Burden: Findings From the Living With Chronic GVHD Patient Survey

BACKGROUND

Development of chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT) results in impaired physical function and quality of life. However, limited data exist regarding the employment and financial impact on patients and caregivers.

OBJECTIVE

The objective of this study was to describe the impact of chronic GVHD on patient employment, disability leave, income, reliance on caregivers, and effects on caregiver employment.

STUDY DESIGN

The Living With Chronic GVHD Patient Survey was a cross-sectional online survey administered from May to August 2020 in the United States to adult HSCT survivors diagnosed with chronic GVHD within the past 5 years. Data on respondent demographics and disease characteristics and the effects of chronic GVHD on employment, income, and need for caregiver assistance were collected. Respondents were also asked to report on the impact of their chronic GVHD on their caregivers' employment. All data were summarized using descriptive statistics; no formal statistical comparisons were conducted.

RESULTS

A total of 165 respondents completed the survey (median age, 57.0 years; 63.6% women; 83.0% White); respondents had been experiencing chronic GVHD for a median (range) of 4.5 (0.1-36.7) years, with a median (range of 0.5 (0-3.6) years from most recent transplant to chronic GVHD diagnosis. Among those employed full- or part-time at the time of their most recent transplant (n=80), 61.3% reported taking disability leave, 58.8% worked reduced hours, 27.5% took a less demanding job, and 33.8% left a job because of chronic GVHD. Additionally, 71.3% believed they had lost income due to chronic GVHD. Among all respondents, 72.1% reported receiving regular caregiver assistance. Respondents commonly reported employment changes among unpaid caregivers (34.5% reduced their working hours; 16.6% terminated a job).

CONCLUSIONS

HSCT survivors who develop chronic GVHD are vulnerable to employment changes and financial hardship. This analysis highlights the need for effective therapies and improved symptom management to reduce the multifaceted burden of chronic GVHD on patients and their caregivers and ultimately improve long-term HSCT outcomes.

Essential Thrombocythemia and Post-Essential Thrombocythemia Myelofibrosis: Updates on Diagnosis, Clinical Aspects, and Management

Although several decades have passed since the description of myeloproliferative neoplasms (MPN), many aspects of their pathophysiology have not been elucidated. In this review, we discuss the mutational landscape of patients with essential thrombocythemia (ET), prognostic scores and salient pathology, and clinical points. We discuss also the diagnostic challenges of differentiating ET from prefibrotic MF. We then focus on post-essential thrombocythemia myelofibrosis (post-ET MF), a rare subset of MPN that is usually studied in conjunction with post-polycythemia vera MF. The transition of ET to post-ET MF is not well studied on a molecular level, and we present available data. Patients with secondary MF could benefit from allogenic hematopoietic stem cell transplantation, and we present available data focusing on post-ET MF.

Improved donor chimerism in relapse myelofibrosis post allogenic stem cell transplant with azacitidine and oral decitabine-First case report

To date, allogenic stem cell transplant (ASCT) remains the only potential curative option for patients with primary myelofibrosis (PMF). However, relapse rates and associated mortality remain a concern. A second ASCT may not be feasible due to advancing age, declined functional status, donor unavailability, toxicities associated with a second ASCT. Herein, we report the first case of utilizing initially azacitidine and subsequently oral decitabine + cedazuridine (decitabine), in the context of relapsed PMF post-ASCT. Utilizing both hypomethylating agents provided disease control and improved donor/myeloid lineage chimerism levels, and the patient also remained transfusion independent, with preserved functional status and quality of life.

Innovative strategies to improve hematopoietic stem cell transplant outcomes in myelofibrosis

Myelofibrosis (MF) is a clonal myeloproliferative neoplasm characterized by inflammation, marrow fibrosis, and an inherent risk of blastic transformation. Hematopoietic allogeneic stem cell transplant is the only potentially curative therapy for this disease, however, survival gains observed for other transplant indications over the past two decades have not been realized for MF. The role of transplantation may also evolve with the use of novel targeted agents. The chronic inflammatory state associated with MF necessitates pretransplantation assessment of end-organ function. Applying the transplant methodology employed for other myeloid disorders to patients with MF fails to acknowledge differences in the underlying disease pathophysiology. Limited understanding of the causes of poor transplant outcomes in this cohort has prevented refinement of transplant eligibility criteria in MF. There is increasing evidence of heterogeneity in molecular disease grade, beyond the clinical manifestations which have traditionally guided transplant timing. Exploring the physiological consequences of disease chronicity unique to MF, acknowledging the heterogeneity in disease grade, and using advanced prognostic models, molecular diagnostics and other organ function diagnostic tools, we present an innovative review of strategies with the potential to improve transplant outcomes in this disease. Larger, prospective studies which consider the impact of molecular-based disease grade are needed for MF transplantation.

High Molecular and Cytogenetic Risk in Myelofibrosis Does Not Benefit From Higher Intensity Conditioning Before Hematopoietic Cell Transplantation: An International Collaborative Analysis

There is no direct evidence to recommend specific conditioning intensities in myelofibrosis undergoing allogeneic hematopoietic cell transplantation, especially in the molecular era. We aimed to compare outcomes of reduced intensity (RIC) or myeloablative conditioning (MAC) transplantation in myelofibrosis with molecular information. The study included 645 genetically annotated patients (with at least driver mutation status available), of whom 414 received RIC and 231 patients received MAC. The median follow-up time from transplantation was 6.0 years for RIC and 9.4 years for MAC. The 6-year overall survival rates for RIC and MAC were 63% (95% confidence interval [CI], 58%-68%) and 59% (95% CI, 52%-66%; P = 0.34) and progression-free survival was 52% (95% CI, 47%-57%) and 52% (95% CI, 45%-59%; P = 0.64). The 2-year cumulative incidence of nonrelapse mortality was 26% (95% CI, 21%-31%) for RIC and 29% (95% CI, 23%-34%) for MAC (P = 0.51). In terms of progression/relapse, the 2-year cumulative incidence was 10% (95% CI, 5%-19%) for RIC and 9% (95% CI, 4%-14%) for MAC (P = 0.46). Higher intensity conditioning did not seem to improve outcomes for higher-risk disease, according to mutational, cytogenetic, and clinical profile. In contrast, patients with reduced performance status, matched unrelated donors, and ASXL1 mutations appeared to benefit from RIC in terms of overall survival.

Myeloproliferative Neoplasms, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology

The classic Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) consist of myelofibrosis, polycythemia vera, and essential thrombocythemia and are a heterogeneous group of clonal blood disorders characterized by an overproduction of blood cells. The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for MPN were developed as a result of meetings convened by a multidisciplinary panel with expertise in MPN, with the goal of providing recommendations for the management of MPN in adults. The Guidelines include recommendations for the diagnostic workup, risk stratification, treatment, and supportive care strategies for the management of myelofibrosis, polycythemia vera, and essential thrombocythemia. Assessment of symptoms at baseline and monitoring of symptom status during the course of treatment is recommended for all patients. This article focuses on the recommendations as outlined in the NCCN Guidelines for the diagnosis of MPN and the risk stratification, management, and supportive care relevant to MF.

Overall survival in the SIMPLIFY-1 and SIMPLIFY-2 phase 3 trials of momelotinib in patients with myelofibrosis

Janus kinase inhibitors (JAKi) approved for myelofibrosis provide spleen and symptom improvements but do not address anemia, a negative prognostic factor. Momelotinib, an inhibitor of ACVR1/ALK2, JAK1 and JAK2, demonstrated activity against anemia, symptoms, and splenomegaly in the phase 3 SIMPLIFY trials. Here, we report mature overall survival (OS) and leukemia-free survival (LFS) from both studies, and retrospective analyses of baseline characteristics and efficacy endpoints for OS associations. Survival distributions were similar between JAKi-naïve patients randomized to momelotinib, or ruxolitinib then momelotinib, in SIMPLIFY-1 (OS HR = 1.02 [0.73, 1.43]; LFS HR = 1.08 [0.78, 1.50]). Two-year OS and LFS were 81.6% and 80.7% with momelotinib and 80.6% and 79.3% with ruxolitinib then momelotinib. In ruxolitinib-exposed patients in SIMPLIFY-2, two-year OS and LFS were 65.8% and 64.2% with momelotinib and 61.2% and 59.7% with best available therapy then momelotinib (OS HR = 0.98 [0.59, 1.62]; LFS HR = 0.97 [0.59, 1.60]). Baseline transfusion independence (TI) was associated with improved survival in both studies (SIMPLIFY-1 HR = 0.474, p = 0.0001; SIMPLIFY-2 HR = 0.226, p = 0.0005). Week 24 TI response in JAKi-naïve, momelotinib-randomized patients was associated with improved OS in univariate (HR = 0.323; p < 0.0001) and multivariate (HR = 0.311; p < 0.0001) analyses. These findings underscore the importance of achieving or maintaining TI in myelofibrosis, supporting the clinical relevance of momelotinib’s pro-erythropoietic mechanism of action, and potentially informing treatment decision-making.

Posttransplantation Cyclophosphamide-based Graft versus Host Disease Prophylaxis with Non-myeloablative Conditioning for Blood or Marrow Transplantation for Myelofibrosis

We describe outcomes with posttransplantation cyclophosphamide and non-myeloablative conditioning based allogeneic blood or marrow transplantation for myelofibrosis using matched or mismatched, family or unrelated donors. The conditioning regimen consisted of fludarabine, cyclophosphamide and total body irradiation. Forty-two patients, with a median age of 63 years, were included, of whom 19% had intermediate-1, 60% had intermediate-2, and 21% had high-risk DIPSS-plus disease, and 60% had atleast one high-risk somatic mutation. Over 90% patients engrafted neutrophils at a median of 19.5 days and 7% had graft failure. At 1 and 3-years, respectively, the overall survival was 65% and 60%, relapse-free survival was 65% and 31%, relapse was 5% and 40%, and non-relapse mortality was 30% and 30%. Acute graft versus host disease grade 3-4 was noted in 17% at 1 year and chronic graft versus host disease requiring systemic therapy in 12% patients. Spleen size ≥ 17 cm or prior splenectomy was associated with inferior relapse-free survival (HR 3.50, 95% CI 1.18-10.37, P=0.02) and higher relapse rate (SDHR not calculable, P=0.01). Age > 60 years (SDHR 0.26, 95% CI: 0.08-0.80, P=0.02) and peripheral blood graft (SDHR 0.34, 95% CI 0.11-0.99, P=0.05) was associated with lower risk of relapse. In our limited sample, the presence of a high-risk mutation was not statistically significantly associated with an inferior outcome although ASXL1 was suggestive of inferior survival (SDHR 2.36. 95% CI 0.85-6.6, P=0.09). Overall, this approach shows comparable outcomes as previously reported and underscores the importance of spleen size in evaluation of transplant candidates.

Impact of prior JAK-inhibitor therapy with ruxolitinib on outcome after allogeneic hematopoietic stem cell transplantation for myelofibrosis: a study of the CMWP of EBMT

JAK1/2 inhibitor ruxolitinib (RUX) is approved in patients with myelofibrosis but the impact of pretreatment with RUX on outcome after allogeneic hematopoietic stem cell transplantation (HSCT) remains to be determined. We evaluated the impact of RUX on outcome in 551 myelofibrosis patients who received HSCT without (n = 274) or with (n = 277) RUX pretreatment. The overall leukocyte engraftment on day 45 was 92% and significantly higher in RUX responsive patients than those who had no or lost response to RUX (94% vs. 85%, p = 0.05). The 1-year non-relapse mortality was 22% without significant difference between the arms. In a multivariate analysis (MVA) RUX pretreated patients with ongoing spleen response at transplant had a significantly lower risk of relapse (8.1% vs. 19.1%; p = 0.04)] and better 2-year event-free survival (68.9% vs. 53.7%; p = 0.02) in comparison to patients without RUX pretreatment. For overall survival the only significant factors were age > 58 years (p = 0.03) and HLA mismatch donor (p = 0.001). RUX prior to HSCT did not negatively impact outcome after transplantation and patients with ongoing spleen response at time of transplantation had best outcome.

Value and pitfalls of assessing bone marrow morphologic findings to predict response in patients with myelofibrosis who undergo hematopoietic stem cell transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative option for patients with myelofibrosis (MF). Bone marrow (BM) morphologic evaluation of myelofibrosis following allo-HSCT is known to be challenging in this context because resolution of morphologic changes is a gradual process.

PATIENTS AND METHODS

We compared BM samples of patients with myelofibrosis who underwent first allo-HSCT and achieved molecular remission by day 100 with BM samples of patients who continued to have persistent molecular evidence of disease following allo-HSCT.

RESULTS

The study group included 29 patients: 17 primary MF, 7 post-polycythemia vera (PV) MF, and 5 post-essential thrombocythemia (ET) MF. In this cohort there were 18 JAK2 p.V617F, 8 CALR; 1 MPL, and 2 patients had concurrent JAK2 p.V617F and MPL mutations. The control group included 5 patients with primary MF, one with post-PV MF, one with post-ET MF (5 JAK2 p.V617F; 2 CALR). Following allo-HSCT, both groups showed reduction in BM cellularity and number of megakaryocytes. The study cohort also less commonly had dense megakaryocyte clusters and endosteal located megakaryocytes and showed less fibrosis. There was no statistical difference in BM cellularity, presence of erythroid islands, degree of osteosclerosis, or megakaryocyte number, size, nuclear lobation, presence of clusters or intrasinusoidal location.

CONCLUSIONS

Following allo-HSCT at 100 days, morphologic evaluation of BM in patients with MF cannot reliably predict persistence versus clearance of molecular evidence of MF. Disappearance of BM MF, dense megakaryocyte clusters, and endosteal localization of megakaryocytes are suggestive of disease response.

Allogeneic blood or marrow transplantation with haploidentical donor and post-transplantation cyclophosphamide in patients with myelofibrosis: a multicenter study

We report the results from a multicenter retrospective study of 69 adult patients who underwent haploidentical blood or marrow transplantation (haplo-BMT) with post-transplantation cyclophosphamide (PTCy) for chronic phase myelofibrosis. The median age at BMT was 63 years (range, 41-74). Conditioning regimens were reduced intensity in 54% and nonmyeloablative in 39%. Peripheral blood grafts were used in 86%. The median follow-up was 23.1 months (range, 1.6-75.7). At 3 years, the overall survival, relapse-free survival (RFS), and graft-versus-host-disease (GVHD)-free-RFS were 72% (95% CI 59-81), 44% (95% CI 29-59), and 30% (95% CI 17-43). Cumulative incidences of non-relapse mortality and relapse were 23% (95% CI 14-34) and 31% (95% CI 17-47) at 3 years. Spleen size ≥22 cm or prior splenectomy (HR 6.37, 95% CI 2.02-20.1, P = 0.002), and bone marrow grafts (HR 4.92, 95% CI 1.68-14.4, P = 0.004) were associated with increased incidence of relapse. Cumulative incidence of acute GVHD grade 3-4 was 10% at 3 months and extensive chronic GVHD was 8%. Neutrophil engraftment was reported in 94% patients, at a median of 20 days (range, 14-70). In conclusion, haplo-BMT with PTCy is feasible in patients with myelofibrosis. Splenomegaly ≥22 cm and bone marrow grafts were associated with a higher incidence of relapse in this study.

McLornan D, Yakoub‐Agha I. Allogeneic hematopoietic cell transplantation in older myelofibrosis patients: A study of the chronic malignancies working party of EBMT and the Spanish Myelofibrosis Registry

Allogeneic hematopoietic cell transplantation (allo-HCT) is increasingly used in older myelofibrosis (MF) patients, but its risk/benefit ratio compared to non-transplant approaches has not been evaluated in this population. We analyzed the outcomes of allo-HCT in 556 MF patients aged ≥65 years from the EBMT registry, and determined the excess mortality over the matched general population of MF patients ≥65 years managed with allo-HCT (n = 556) or conventional drug treatment (n = 176). The non-transplant cohort included patients with intermediate-2 or high risk DIPSS from the Spanish Myelofibrosis Registry. After a median follow-up of 3.4 years, the estimated 5-year survival rate, non-relapse mortality (NRM), and relapse incidence after transplantation was 40%, 37%, and 25%, respectively. Busulfan-based conditioning was associated with decreased mortality (HR: 0.7, 95% CI: 0.5-0.9) whereas the recipient CMV+/donor CMV- combination (HR: 1.7, 95% CI: 1.2-2.4) and the JAK2 mutated genotype (HR: 1.9, 95% CI: 1.1-3.5) predicted higher mortality. Busulfan-based conditioning correlated with improved survival due to less NRM, despite its higher relapse rate when compared with melphalan-based regimens. Excess mortality was higher in transplanted patients than in the non-HCT cohort in the first year of follow-up (ratio: 1.93, 95% CI: 1.13-2.80), whereas the opposite occurred between the fourth and eighth follow-up years (ratio: 0.31, 95% CI: 0.18-0.53). Comparing the excess mortality of the two treatments, male patients seemed to benefit more than females from allo-HCT, mainly due to their worse prognosis with non-transplant approaches. These findings could potentially enhance counseling and treatment decision-making in elderly transplant-eligible MF patients.

Survival following allogeneic transplant in patients with myelofibrosis

Allogeneic hematopoietic cell transplantation (HCT) is the only curative therapy for myelofibrosis (MF). In this large multicenter retrospective study, overall survival (OS) in MF patients treated with allogeneic HCT (551 patients) and without HCT (non-HCT) (1377 patients) was analyzed with Cox proportional hazards model. Survival analysis stratified by the Dynamic International Prognostic Scoring System (DIPSS) revealed that the first year of treatment arm assignment, due to upfront risk of transplant-related mortality (TRM), HCT was associated with inferior OS compared with non-HCT (non-HCT vs HCT: DIPSS intermediate 1 [Int-1]: hazard ratio [HR] = 0.26, P < .0001; DIPSS-Int-2 and higher: HR, 0.39, P < .0001). Similarly, in the DIPSS low-risk MF group, due to upfront TRM risk, OS was superior with non-HCT therapies compared with HCT in the first-year post treatment arm assignment (HR, 0.16, P = .006). However, after 1 year, OS was not significantly different (HR, 1.38, P = .451). Beyond 1 year of treatment arm assignment, an OS advantage with HCT therapy in Int-1 and higher DIPSS score patients was observed (non-HCT vs HCT: DIPSS-Int-1: HR, 2.64, P < .0001; DIPSS-Int-2 and higher: HR, 2.55, P < .0001). In conclusion, long-term OS advantage with HCT was observed for patients with Int-1 or higher risk MF, but at the cost of early TRM. The magnitude of OS benefit with HCT increased as DIPSS risk score increased and became apparent with longer follow-up.

Allogeneic Hemopoietic Stem Cell Transplantation for Myelofibrosis: 2021

The aim of this review is to update the current status of allogeneic hemopoietic stem cell transplants (HSCT) for patients with myelofibrosis (MF). We have first summarized the issue of an indication for allogeneic HSCT, discussing several prognostic scoring systems, developed to predict the outcome of MF, and therefore to identify patients who will benefit of an allogeneic HSCT. Patients with low risk MF are usually not selected for a transplant, whereas patients with intermediate or high risk MF are eligible. A separate issue, is how to predict the outcome of HSCT: we will outline a clinical molecular myelofibrosis transplant scoring system (MTSS), which predicts overall survival, ranging from 90% for low risk patients, to 20% for very high risk patients. We will also discuss transfusion burden and spleen size, as predictors of transplant outcome. The choice of a transplant platform including the conditioning regimen, the stem cell source and GvHD prophylaxis, are crucial for a successful program in MF, and will be outlined. Complications such as poor graft function, graft failure, GvHD and relapse of the disease, will also be reviewed. Finally we discuss monitoring the disease after HSCT with donor chimerism, driver mutations and hematologic data. We have made an effort to make this review as comprehensive and up to date as possible, and we hope it will provide some useful data for the clinicians.

Association of Factors Influencing Selection of Upfront Hematopoietic Cell Transplantation versus Nontransplantation Therapies in Myelofibrosis

Despite the curative potential of allogeneic hematopoietic cell transplantation (HCT) for myelofibrosis (MF), a significant number of patients with MF do not undergo HCT. Factors influencing treatment preferences in these patients have not been well studied. This study was conducted to identify patient-, disease-, and donor-related factors influencing the decision regarding HCT in patients with MF. A secondary objective was to compare survival between patients who elected upfront HCT and those who opted for nontransplantation therapy. We conducted a retrospective chart review amongst patients meeting criteria for transplant indication, evaluating clinical characteristics, treatment preferences, and outcomes. Of the 183 study eligible patients age <70 years, 129 (70%) developed an HCT indication. Age >60 years was significantly associated with higher rates of HLA-typing refusal (13 of 72 versus 1 of 44; P = .02). Caucasian ethnicity was significantly associated with an increased rate of identifying well-matched donors compared with non-Caucasian ethnicity (75% versus 48%; P = .02). Of the 69 patients with well-matched donors, 34 (49%) preferred to not pursue upfront HCT despite an indication for transplantation. Patient preference for nontransplantation therapies was the most common reason for declining HCT. We did not find any difference in survival between patients pursuing upfront HCT and those opting for nontransplantation therapies, although more patients in the HCT arm were in remission at the last follow-up. Patients of Caucasian ethnicity were significantly more likely than non-Caucasian patients to identify a well-matched donor. Despite availability of a well-matched donor, a significant proportion of MF patients with an indication for transplantation do not pursue HCT. Patient age, donor type, and patient preference play major roles in the selection of upfront HCT. Although a survival difference was not observed between upfront HCT versus non-transplant therapy, more patients in the HCT arm were in remission at the last follow-up.

Illuminating novel biological aspects and potential new therapeutic approaches for chronic myeloproliferative malignancies

This review reflects the presentations and discussion at the 14th post-American Society of Hematology (ASH) International Workshop on Chronic Myeloproliferative Malignancies, which took place on the December 10 and 11, 2019, immediately after the 61st ASH Annual Meeting in Orlando, Florida. Rather than present a resume of the proceedings, we address some of the topical translational science research and clinically relevant topics in detail. We consider how recent studies using single-cell genomics and other molecular methods reveal novel aspects of hematopoiesis which in turn raise the possibility of new therapeutic approaches for patients with myeloproliferative neoplasms (MPNs). We discuss how alternative therapies could benefit patients with chronic myeloid leukemia who develop BCR-ABL1 mutant subclones following ABL1-tyrosine kinase inhibitor therapy. In MPNs, we focus on efforts beyond JAK-STAT and the merits of integrating activin receptor ligand traps, interferon-α, and allografting in the current treatment algorithm for patients with myelofibrosis.

Salvage Therapy Using Azacitidine for Relapsed Primary Myelofibrosis after Cord Blood Transplantation

We present the case of a 53-year-old woman with prefibrotic stage primary myelofibrosis (PMF) who underwent cord blood transplantation. Nine years after transplantation, she relapsed, which was confirmed by a bone marrow examination. We decided to treat her using azacitidine. After three courses of azacitidine, a partial cytogenetic response was confirmed. Azacitidine maintenance therapy successfully maintained a low level of recipient-origin peripheral blood cells with a stable hematological condition. Azacitidine may therefore be a promising therapeutic option for PMF patients who relapse after allogeneic stem cell transplantation.

Treosulfan-Based Conditioning Regimen for Second Allograft in Patients with Myelofibrosis

Simple Summary

Currently, the only curative therapy in myelofibrosis is allogeneic hematopoietic stem cell transplantation. Donor lymphocyte infusion and second stem cell transplantation are the two main treatment options for myelofibrosis patients who relapse after the first transplantation. The optimal conditioning regimen for the second transplantation in myelofibrosis patients is not well defined. Our study aimed to address this question and showed that treosulfan-based conditioning for second allograft in relapsed myelofibrosis patients resulted in longtime freedom from disease in about 50% of the patients. This data supports the second allogeneic hematopoietic stem cell transplantation with a less toxic treosulfan-based conditioning regimen that is effective in relapsed, donor lymphocyte infusion resistant myelofibrosis patients with long term low transplant-related mortality and relapse rates.

Abstract

Relapse after allogeneic hematopoietic stem cell transplantation (AHSCT) in myelofibrosis (MF) patients remains as a significant issue despite advances in transplantation procedures and significant prolongation in survival. Second AHSCT is a potential treatment option but associated with high treatment-related mortality and novel less toxic conditioning regimens are needed. In 33 MF patients with relapse after AHSCT and failure to donor lymphocyte infusion (DLI) we investigated treosulfan (36–42 g/m²) in combination with fludarabine and anti-thymocyte globulin (ATG) as conditioning regimen for a second AHSCT with matched related (n = 2), unrelated (n = 23), or mismatched unrelated (n = 8) donors. All patients achieved leukocyte engraftment after a median of 11 days, and 56 ± 13% experienced acute GVHD grade II–IV at day 100. The therapy-related mortality at day 100 and at 3 years was 16% and 31%, respectively. The cumulative incidence of relapse at 5 years was 16%, resulting in a 5-year disease-free and overall survival of 45% and 47%, respectively. Treosulfan-based conditioning for second allograft in relapsed MF patients resulted in about 50% of the patients in long-term freedom from disease.

Incidence and Outcome of Late Relapse after Allogeneic Stem Cell Transplantation for Myelofibrosis

In this cross-sectional study, we retrospectively evaluated the files of 227 patients with myelofibrosis who underwent transplantation between 1994 and 2015 for relapse later than 5 years after allogeneic stem cell transplantation (SCT). A total of 94 patients who were alive and in remission at 5 years were identified with follow-up of at least 5 years (median, 9.15 years) after SCT. Thirteen patients (14%) experienced late molecular (n = 6) or hematologic (n = 7) relapse at a median of 7.1 years while 81 patients did not experience relapse. Relapse patients received either donor lymphocyte infusion (DLI) (n = 7) and/or second transplantation (n = 4). Of those, 72.7% achieved again full donor cell chimerism and molecular remission, and after a median follow-up of 45 months, the 3-year overall survival rates for patients with or without relapse were 90.9% (95% confidence interval [CI], 77% to 100%) and 98.8% (95% CI, 96% to 100%), respectively (P = .13). We conclude that late relapse occurs in about 14% of the patients and the majority can be successfully salvaged with DLI and/or second allograft. All patients with molecular relapse are alive and support the long-time molecular monitoring in myelofibrosis patients after allogeneic SCT.

MPN: The Molecular Drivers of Disease Initiation, Progression and Transformation and their Effect on Treatment

Myeloproliferative neoplasms (MPNs) constitute a group of disorders identified by an overproduction of cells derived from myeloid lineage. The majority of MPNs have an identifiable driver mutation responsible for cytokine-independent proliferative signalling. The acquisition of coexisting mutations in chromatin modifiers, spliceosome complex components, DNA methylation modifiers, tumour suppressors and transcriptional regulators have been identified as major pathways for disease progression and leukemic transformation. They also confer different sensitivities to therapeutic options. This review will explore the molecular basis of MPN pathogenesis and specifically examine the impact of coexisting mutations on disease biology and therapeutic options.

Determinants of survival in myelofibrosis patients undergoing allogeneic hematopoietic cell transplantation

We aimed to evaluate the determinants of survival in myelofibrosis patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) and to describe factors predicting the main post-HCT complications. This retrospective study by the European Society for Blood and Marrow Transplantation included 2916 myelofibrosis patients who underwent first allo-HCT from an HLA-identical sibling or unrelated donor between 2000 and 2016. After a median follow-up of 4.7 years from transplant, projected median survival of the series was 5.3 years. Factors independently associated with increased mortality were age ≥ 60 years and Karnofsky Performance Status <90% at transplant, and occurrence of graft failure, grades III-IV acute graft-vs.-host disease (aGVHD), and disease progression/relapse during follow-up. The opposing effects of chronic graft-vs.-host disease (GVHD) on non-relapse mortality and relapse incidence resulted in a neutral influence on survival. Graft failure increased in unrelated donor recipients and decreased with myeloablative conditioning (MAC) and negative donor/recipient cytomegalovirus serostatus. Risk of grades III-IV aGVHD was higher with unrelated donors and decreased with MAC. Relapse incidence tended to be higher in patients with intermediate-2/high-risk DIPSS categories and to decrease in CALR-mutated patients. Acute and chronic GVHD reduced the subsequent risk of relapse. This information has potential implications for patient counseling and clinical decision-making.

A provider's guide to primary myelofibrosis: pathophysiology, diagnosis, and management

Although understanding of the pathogenesis and molecular biology of primary myelofibrosis continues to improve, treatment options are limited, and several biological features remain unexplained. With an appropriate clinical history, exam, laboratory evaluation, and bone marrow biopsy, the diagnosis can often be established. Recent studies have better characterized prognostic factors and driver mutations in myelofibrosis, facilitated by use of next-generation sequencing. These advances have facilitated development of a management strategy that is based on both risk factors and clinical phenotype. For low-risk patients, treatment will depend on symptom severity. For patients with higher-risk disease, several treatments are available including JAK inhibitors, allogeneic hematopoietic stem cell transplant, and clinical trials using novel molecularly targeted therapies and rational drug combinations. In this review, we outline what is known about the disease pathogenesis, discuss an approach to reaching the diagnosis, review the prognosis of myelofibrosis, and detail current therapeutic strategies.

Early post-transplantation factors predict survival outcomes in patients undergoing allogeneic hematopoietic cell transplantation for myelofibrosis

Factors predicting allogeneic hematopoietic cell transplantation (HCT) outcomes in myelofibrosis in the early post-HCT period have not been defined thus far. We attempt to study such factors that can help identify patients at a higher risk of relapse or death. This retrospective study included 79 patients who underwent first HCT for myelofibrosis at three centers between 2005 and 2016. Univariate analysis showed that red blood cell (RBC) transfusion dependence (HR 9.02, 95% CI 4.0–20.35), platelet transfusion dependence (HR 8.17, 95%CI 3.83–17.37), 100% donor chimerism in CD33 + cells (HR 0.21, 95%CI 0.07–0.62), unfavorable molecular status (HR 4.41, 95%CI 1.87–10.39), normal spleen size (HR 0.42, 95%CI 0.19–0.94), grade ≥ 2 bone marrow fibrosis (vs. grade ≤ 1; HR 2.7, 95%CI 1.1–6.93) and poor graft function (HR 2.6, 95%CI 1.22–5.53) at day +100 were statistically significantly associated with relapse-free survival (RFS). RBC transfusion dependence and unfavorable molecular status were also statistically significant in the multivariate analysis. Patients in whom both of these factors were present had a significantly worse RFS when compared to those with one or none. While limited by a small sample size, we demonstrate the significance of transfusion dependence and molecular status at day +100 in predicting outcomes.

Allogeneic hematopoietic stem-cell transplantation for myelofibrosis

Myelofibrosis is one of the Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms with heterogeneous clinical course. Though many treatment options, including Janus kinase (JAK) inhibitors, have provided clinical benefits and improved survival, allogeneic hematopoietic stem-cell transplantation (AHSCT) remains the only potentially curative therapy. Considering the significant transplant-related morbidity and mortality, it is crucial to decide who to proceed to AHSCT, and when. In this review, we discuss recent updates in patient selection, prior splenectomy, conditioning regimen, donor type, molecular mutation, and other factors affecting AHSCT outcomes. Relapse is a major cause of treatment failure; we also describe recent data on minimal residual disease monitoring and management of relapse. In addition, emerging studies have reported pretransplant therapy with ruxolitinib for myelofibrosis showing favorable results, and further research is needed to explore its use in the post-transplant setting.

Allogeneic Hematopoietic Stem Cell Transplantation for Post-essential Thrombocythemia and Post-polycythemia Vera Myelofibrosis

Objective Little information is available about the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) for patients with secondary myelofibrosis from essential thrombocythemia (ET) and polycythemia vera (PV). A nationwide retrospective study of the outcome of HSCT for post-ET and post-PV myelofibrosis was conducted in Japan. Patients and Methods Clinical data for patients with post-ET (n=29) and post-PV (n=9) myelofibrosis who had received first allogeneic HSCT were extracted from the Transplant Registry Unified Management Program, which is a registry of the outcomes of HSCT in Japan. Results Five patients died without neutrophil recovery within 60 days after transplantation. The incidence of neutrophil recovery was significantly lower in umbilical cord blood (UCB) transplantation than in related donor transplantation (40% vs. 92%, p=0.010). The 1-year non-relapse mortality for post-ET and post-PV myelofibrosis was 35% and 27%, respectively (p=0.972). No patient or transplantation characteristics were associated with non-relapse mortality. The 4-year overall survival for post-ET and post-PV myelofibrosis was 46% and 65%, respectively (p=0.362). A univariate analysis identified UCB transplantation (vs. related donor, p=0.017) and ≥10 times red blood cell transfusions before transplantation (vs. <10 times, p=0.037) as predictive of a lower overall survival. Conclusion Allogeneic HSCT provides a long-term survival for at least some patients with post-ET and post-PV myelofibrosis. Further studies with more patients are required to determine the best alternative donor.

The role of allogeneic stem-cell transplant in myelofibrosis in the era of JAK inhibitors: a case-based review

Allogeneic hematopoietic stem-cell transplantation (HSCT) is, at present, the only potentially curative therapy for myelofibrosis (MF). Despite many improvements, outcomes of HSCT are still burdened by substantial morbidity and high transplant-related mortality. Allogeneic transplant is generally considered in intermediate-2 and high-risk patients aged <70 years, but the optimal selection of patients and timing of the procedure remains under debate, as does as the role of JAK inhibitors in candidates for HSCT. Starting from a real-life clinical case scenario, herein we examine some of the crucial issues of HSCT for MF in light of recent refinements on MF risk stratification, data on the use of ruxolitinib before and after transplant and findings on the impact of different conditioning regimens and donor selection.