Dynamic International Prognostic Scoring System (DIPSS) predicts progression to acute myeloid leukemia in primary myelofibrosis

Treosulfan compared to busulfan in allogeneic haematopoietic stem cell transplantation for myelofibrosis: a registry-based study from the Chronic Malignancies Working Party of the EBMT

We aimed to compare outcomes following treosulfan (TREO) or busulfan (BU) conditioning in a large cohort of myelofibrosis (MF) patients from the EBMT registry. A total of 530 patients were included; 73 received TREO and 457 BU (BU ≤ 6.4 mg/kg in 134, considered RIC, BU > 6.4 mg/kg in 323 considered higher dose (HD)). Groups were compared using adjusted Cox models. Cumulative incidences of engraftment and acute GVHD were similar across the 3 groups. The TREO group had significantly better OS than BU-HD (HR:0.61, 95% CI: 0.39-0.93) and a trend towards better OS over BU-RIC (HR: 0.66, 95% CI: 0.41-1.05). Moreover, the TREO cohort had a significantly better Progression-Free-Survival (PFS) than both the BU-HD (HR: 0.57, 95% CI: 0.38-0.84) and BU-RIC (HR: 0.60, 95% CI: 0.39-0.91) cohorts, which had similar PFS estimates. Non-relapse mortality (NRM) was reduced in the TREO and BU-RIC cohorts (HR: 0.44, 95% CI: 0.24-0.80 TREO vs BU-HD; HR: 0.54, 95% CI: 0.28-1.04 TREO vs BU-RIC). Of note, relapse risk did not significantly differ across the three groups. In summary, within the limits of a registry-based study, TREO conditioning may improve PFS in MF HSCT and have lower NRM than BU-HD with a similar relapse risk to BU-RIC. Prospective studies are needed to confirm these findings.

Ruxolitinib Adherence in Myelofibrosis and Polycythemia Vera: the "RAMP" Italian multicenter prospective study

Ruxolitinib is beneficial in patients with myelofibrosis (MF) and polycythemia vera (PV). Information on ruxolitinib adherence is scant. The Ruxolitinib Adherence in Myelofibrosis and Polycythemia Vera (RAMP) prospective multicenter study (NCT06078319) included 189 ruxolitinib-treated patients. Patients completed the Adherence to Refills and Medications Scale (ARMS) and Distress Thermometer and Problem List (DTPL) at the earliest convenience, after registration in the study, and at later timepoints. At week-0, low adherence (ARMS > 14) and high distress (DT ≥ 4) were declared by 49.7% and 40.2% of patients, respectively. The main reason for low adherence was difficult ruxolitinib supply (49%), intentional (4.3%) and unintentional (46.7%) non-take. In multivariable regression analysis, low adherence was associated to male sex (p = 0.001), high distress (p < 0.001), and treatment duration ≥ 1 year (p = 0.03). Over time, rates of low adherence and high distress remained stable, but unintentional non-take decreased from 47.9% to 26.0% at week-48. MF patients with stable high adherence/low distress were more likely to obtain/maintain the spleen response at week-24. Low adherence to ruxolitinib represents an unmet clinical need that require a multifaceted approach, based on reason behind it (patients characteristics and treatment duration). Its recognition may help distinguishing patients who are truly refractory and those in need of therapy optimization.

The molecular landscape of myeloproliferative neoplasms associated with splanchnic vein thrombosis: Current perspective

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) are classically represented by polycythemia vera, essential thrombocythemia, and primary myelofibrosis. BCR::ABL1-negative MPNs are significantly associated with morbidity and mortality related to an increased risk of thrombo-hemorrhagic events. They show a consistent association with splanchnic vein thrombosis (SVT), either represented by the portal, mesenteric or splenic vein thrombosis, or Budd-Chiari Syndrome. SVT is also a frequent presenting manifestation of MPN. MPNs associated with SVT show a predilection for younger women, high association with JAK2V617F mutation, low JAK2V617F variant allele frequency (generally <10 %), and low rates of CALR, MPL, or JAK2 exon 12 mutations. Next-Generation Sequencing techniques have contributed to deepening our knowledge of the molecular landscape of such cases, with potential diagnostic and prognostic implications. In this narrative review, we analyze the current perspective on the molecular background of MPN associated with SVT, pointing as well future directions in this field.

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.

A Prognostic Model to Predict Ruxolitinib Discontinuation and Death in Patients with Myelofibrosis

Most patients with myelofibrosis (MF) discontinue ruxolitinib (JAK1/JAK2 inhibitor) in the first 5 years of therapy due to therapy failure. As the therapeutic possibilities of MF are expanding, it is critical to identify patients predisposed to early ruxolitinib monotherapy failure and worse outcomes. We investigated predictors of early ruxolitinib discontinuation and death on therapy in 889 patients included in the "RUX-MF" retrospective study. Overall, 172 patients were alive on ruxolitinib after ≥5 years (long-term ruxolitinib, LTR), 115 patients were alive but off ruxolitinib after ≥5 yrs (short-term RUX, STR), and 123 patients died while on ruxolitinib after <5 yrs (early death on ruxolitinib, EDR). The cumulative incidence of the blast phase was similar in LTR and STR patients (p = 0.08). Overall survival (OS) was significantly longer in LTR pts (p = 0.002). In multivariate analysis, PLT < 100 × 109/L, Hb < 10 g/dL, primary MF, absence of spleen response at 3 months and ruxolitinib starting dose <10 mg BID were associated with higher probability of STR. Assigning one point to each significant variable, a prognostic model for STR (STR-PM) was built, and three groups were identified: low (score 0-1), intermediate (score 2), and high risk (score ≥ 3). The STR-PM may identify patients at higher risk of failure with ruxolitinib monotherapy who should be considered for alternative frontline strategies.

Incidence of blast phase in myelofibrosis according to anemia severity

Myelofibrosis (MF) is a clonal malignancy frequently characterized by anemia and in 10%-20% of cases it can evolve into blast phase (BP). Anemia in MF is associated with reduced survival and -in primary MF- also with an increased probability of BP. Conventional treatments for anemia have limited effectiveness in MF. Within a dataset of 1752 MF subjects largely unexposed to ruxolitinib (RUX), BP incidence was 2.5% patients per year (p-y). This rate reached respectively 4.3% and 4.5% p-y in case of patients with common terminology criteria for adverse events (CTCAE) grade 3/4 and grade 2 anemia, respectively, that represented together 32% of the cohort. Among 273 MF cases treated with RUX, BP incidence was 2.89% p-y and it reached 4.86% p-y in subjects who started RUX with CTCAE grade 2 anemia (one third of total). Within patients with red blood cell transfusion-dependency at 6 months of RUX (21% of the exposed), BP rate was 4.2% p-y. Our study highlights a relevant incidence of BP in anemic MF patients, with a similar rate whether treated with or without RUX. These findings will help treating physicians to make decisions on the safety profile of innovative anemia treatments.

Myelofibrosis

The clinical phenotype of primary and post-polycythemia vera and postessential thrombocythemia myelofibrosis (MF) is dominated by splenomegaly, symptomatology, a variety of blood cell alterations, and a tendency to develop vascular complications and blast phase. Diagnosis requires assessing complete cell blood counts, bone marrow morphology, deep genetic evaluations, and disease history. Driver molecular events consist of JAK2V617F, CALR, and MPL mutations, whereas about 8% to 10% of MF are "triple-negative." Additional myeloid-gene variants are described in roughly 80% of patients. Currently available clinical-based and integrated clinical/molecular-based scoring systems predict the survival of patients with MF and are applied for conventional treatment decision-making, indication to stem cell transplant (SCT) and allocation in clinical trials. Standard treatment consists of anemia-oriented therapies, hydroxyurea, and JAK inhibitors such as ruxolitinib, fedratinib, and pacritinib. Overall, spleen volume reduction of 35% or greater at week 24 can be achieved by 42% of ruxolitinib-, 47% of fedratinib-, 19% of pacritinib-, and 27% of momelotinib-treated patients. Now, it is time to move towards new paradigms for evaluating efficacy like disease modification, that we intend as a robust and unequivocal effect on disease biology and/or on patient survival. The growing number of clinical trials potentially pave the way for new strategies in patients with MF. Translational studies of some molecules showed an early effect on bone marrow fibrosis and on variant allele frequencies of myeloid genes. SCT is still the only curative option, however, it is associated with relevant challenges. This review focuses on the diagnosis, prognostication, and treatment of MF.

Hitting the brakes on accelerated and blast-phase myeloproliferative neoplasms: current and emerging concepts

The BCR-ABL-negative myeloproliferative neoplasms (MPNs) have a variable risk of progressing to accelerated- or blast-phase MPN (MPN-AP/MPN-BP), defined by the presence of 10% to 19% and more than or equal to 20% myeloid blasts in the peripheral blood or bone marrow, respectively. The molecular processes underlying the progression to MPN-AP/MPN-BP are becoming increasingly understood with the acquisition of additional mutations in epigenetic modifiers (eg, ASXL1, EZH2, TET2), TP53, the Ras pathway, or splicing factors (eg, SRSF2, U2AF1), having been described as important steps in this evolutionary process. At least partially driven by the enrichment of these high-risk molecular features, the prognosis of patients with MPN-BP remains inferior to other patients with acute myeloid leukemia, with a median overall survival of 3 to 6 months. Allogeneic hematopoietic cell transplantation remains the only potentially curative therapeutic modality, but only a minority of patients are eligible. In the absence of curative intent, therapeutic strategies or palliative treatment with hypomethylating agents as monotherapy or in combination with ruxolitinib or venetoclax can be considered. Several novel agents are in various stages of clinical development but are not available for routine use at this point, highlighting the need for ongoing research and the prioritization of clinical trial enrollment when feasible.

Germline-somatic JAK2 interactions are associated with clonal expansion in myelofibrosis

Myelofibrosis is a rare myeloproliferative neoplasm (MPN) with high risk for progression to acute myeloid leukemia. Our integrated genomic analysis of up to 933 myelofibrosis cases identifies 6 germline susceptibility loci, 4 of which overlap with previously identified MPN loci. Virtual karyotyping identifies high frequencies of mosaic chromosomal alterations (mCAs), with enrichment at myelofibrosis GWAS susceptibility loci and recurrently somatically mutated MPN genes (e.g., JAK2). We replicate prior MPN associations showing germline variation at the 9p24.1 risk haplotype confers elevated risk of acquiring JAK2^V617F mutations, demonstrating with long-read sequencing that this relationship occurs in cis. We also describe recurrent 9p24.1 large mCAs that selectively retained JAK2^V617F mutations. Germline variation associated with longer telomeres is associated with increased myelofibrosis risk. Myelofibrosis cases with high-frequency JAK2 mCAs have marked reductions in measured telomere length – suggesting a relationship between telomere biology and myelofibrosis clonal expansion. Our results advance understanding of the germline-somatic interaction at JAK2 and implicate mCAs involving JAK2 as strong promoters of clonal expansion of those mutated clones.

Myelofibrosis is a risk factor for the development of Acute Myeloid Leukaemia. Here, the authors carry out an integrated genomic investigation of 933 myelofibrosis patients, and identified interactions between germline and somatic variation in patients who required haematopoietic cell transplantation.

Towards a Personalized Definition of Prognosis in Philadelphia-Negative Myeloproliferative Neoplasms

Purpose of Review

Philadelphia-negative myeloproliferative neoplasms (MPNs) include polycythemia vera (PV), essential thrombocythemia (ET), prefibrotic (pre-), and overt-primary myelofibrosis (primary MF, PMF). PV and ET could evolve into secondary MF (SMF), whose early diagnosis relies on monitoring signs of possible progression. All MPNs have a risk of blast phase (BP), that is associated with a very dismal outcome. Overall survival (OS) is different among MPNs, and disease-specific prognostic scores should be applied for a correct clinical management. In this review, an overview of current prognostic scores in MPNs will be provided.

Recent Findings

The biological complexity of MPNs and its role on the trajectory of disease outcome have led to the design of integrated prognostic models that are nowadays of common use in PMF patients. As for PV and ET, splicing gene mutations could have a detrimental role, but with the limit of the not routinary recommended application of extensive molecular analysis in these diseases. SMF is recognized as a distinct entity compared to PMF, and OS estimates should be calculated by the MYSEC-PM (Myelofibrosis SECondary-prognostic model). Both in PMF and SMF, decisions as selection of patients potentially candidates to allogenic stem cell transplant or that could benefit from an early shift from standard treatment are based not only on conventional prognostic scores, but also on multivariable algorithms.

Summary

The expanding landscape of risk prediction for OS, evolution to BP, and SMF progression from PV/ET informs personalized approach to the management of patients affected by MPNs.

Peripheral blasts are associated with responses to ruxolitinib and outcomes in patients with chronic-phase myelofibrosis

Background

The presence of peripheral blasts (PB) is a negative prognostic factor in patients with primary and secondary myelofibrosis (MF) and PB ≥4% was associated with a particularly unfavorable prognosis. Ruxolitinib (RUX) is the JAK1/2 inhibitor most used for treatment of MF‐related splenomegaly and symptoms. Its role has not been assessed in correlation with PB.

Methods

In 794 chronic‐phase MF patients treated with RUX, we evaluated the impact of baseline percentage of PB on response (spleen and symptoms responses) and outcome (RUX discontinuation‐free, leukemia‐free, and overall survival). Three subgroups were compared: PB‐0 (no PB, 61.3%), PB‐4 (PB 1%‐4%, 33.5%), and PB‐9 (PB 5%‐9%, 5.2%).

Results

At 3 and 6 months, spleen responses were less frequently achieved by PB‐4 (P = .001) and PB‐9 (P = .004) compared to PB‐0 patients. RUX discontinuation‐free, leukemia‐free, and overall survival were also worse for PB‐4 and PB‐9 patients (P = .001, P = .002, and P < .001, respectively).

Conclusions

Personalized approaches beyond RUX monotherapy may be useful in PB‐4 and particularly in PB‐9 patients.

In 794 chronic‐phase myelofibrosis patients treated with ruxolitinib, the impact of the baseline percentage of peripheral blasts (PB) on response and outcome was evaluated. Three subgroups were compared: PB‐0 (no PB, 61.3%), PB‐4 (PB 1%‐4%, 33.5%), and PB‐9 (PB 5%‐9%, 5.2%). At 3 and 6 months, spleen responses were less frequently achieved by PB‐4 (P = .001) and PB‐9 (P = .004) compared to PB‐0 patients; ruxolitinib discontinuation‐free, leukemia‐free, and overall survival were also worse for PB‐4 and PB‐9 patients (P = .001, P = .002, and P < .001, respectively).

Reduced intensity hematopoietic stem cell transplantation for myelofibrosis in accelerated-phase

Results of this first report in accelerated-phase myelofibrosis may encourage clinicians to refer these patients for curative treatment.

Accelerated-phase myelofibrosis without prior cytoreduction showed excellent 5-year survival (65%) but higher relapse vs chronic phase.

Accelerated-phase myelofibrosis, currently defined by circulating blasts 10% to 19%, usually confers very high risk for progression and poor outcome. The outcome of hematopoietic stem cell transplantation for accelerated-phase myelofibrosis has not been evaluated yet. We analyzed the outcome of 349 clinically and genetically annotated patients with primary or secondary myelofibrosis undergoing reduced intensity transplantation, of whom 35 had accelerated-phase myelofibrosis. In comparison with chronic-phase (<10% blasts) myelofibrosis, median leukocyte counts were higher, more patients had constitutional symptoms, and RAS mutations were detected more frequently in the accelerated-phase group. After a median follow-up of 5.9 years, estimated 5-year overall survival was 65% (95% confidence interval [CI], 49% to 81%) vs 64% (95% CI, 59% to 69%) for the chronic-phase group (P = .91), and median overall survival was not reached. In terms of relapse-free survival, estimated 5-year outcome for the accelerated-phase group was 49% (95% CI, 32% to 67%) vs 55% (95% CI, 50% to 61%) for the chronic-phase group (P = .65). Estimated 5-year nonrelapse mortality was 20% (95% CI, 8% to 33%) for the accelerated-phase group vs 30% (95% CI, 24% to 35%; P = .25) for the chronic-phase group. In terms of relapse, 5-year incidence was 30% (95% CI, 14% to 46%) for the accelerated-phase group vs 15% (95% CI, 11% to 19%) for the chronic-phase group (P = .02). Results were confirmed in multivariable analysis and propensity score matching. In conclusion, reduced intensity transplantation showed excellent survival but higher relapse for accelerated-phase myelofibrosis.

Progression of Myeloproliferative Neoplasms (MPN): Diagnostic and Therapeutic Perspectives

Classical BCR-ABL-negative myeloproliferative neoplasms (MPN) are a heterogeneous group of hematologic malignancies, including essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF), as well as post-PV-MF and post-ET-MF. Progression to more symptomatic disease, such as overt MF or acute leukemia, represents one of the major causes of morbidity and mortality. There are clinically evident but also subclinical types of MPN progression. Clinically evident progression includes evolution from ET to PV, ET to post-ET-MF, PV to post-PV-MF, or pre-PMF to overt PMF, and transformation of any of these subtypes to myelodysplastic neoplasms or acute leukemia. Thrombosis, major hemorrhage, severe infections, or increasing symptom burden (e.g., pruritus, night sweats) may herald progression. Subclinical types of progression may include increases in the extent of bone marrow fibrosis, increases of driver gene mutational allele burden, and clonal evolution. The underlying causes of MPN progression are diverse and can be attributed to genetic alterations and chronic inflammation. Particularly, bystander mutations in genes encoding epigenetic regulators or splicing factors were associated with progression. Finally, comorbidities such as systemic inflammation, cardiovascular diseases, and organ fibrosis may augment the risk of progression. The aim of this review was to discuss types and mechanisms of MPN progression and how their knowledge might improve risk stratification and therapeutic intervention. In view of these aspects, we discuss the potential benefits of early diagnosis using molecular and functional imaging and exploitable therapeutic strategies that may prevent progression, but also highlight current challenges and methodological pitfalls.

Effect of pre-transplant JAK1/2 inhibitors and CD34 dose on transplant outcomes in myelofibrosis

Allogeneic hematopoeitic cell transplantation (allo-HCT) is the only curative treatment for myelofibrosis (MF). We evaluate the impact of various factors on survival outcomes post-transplant in MF. Data of 89 consecutive MF patients (primary 47%) who underwent allo-HCT between 2005 and 2018 was evaluated. Fifty-four percent patients had received JAK1/2 inhibitors (JAKi) pre-HCT. The median CD34 count was 7.1x10⁶ cells/kg. Graft failure was seen in 10% of the patients. Grade 3-4 acute GVHD (aGVHD) and moderate/severe chronic graft versus host disease (cGVHD) occurred in 24% and 40% patients, respectively. Two-year overall survival (OS) and relapse free survival (RFS) were 51% and 43%, respectively. Cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) at 2 years were 11% and 46%, respectively. Higher CD34 cell dose (≤5 × 10⁶ cells/kg vs 5-9 or ≥9 × 10⁶  cells/kg) and lower pre-HCT ferritin (</=1000 ng/ml) were associated with better OS, RFS and lower NRM. Grade 3-4 aGVHD was associated with higher NRM. Use of pre-transplant JAKi was associated with lower incidence of grade 3-4 aGVHD. In summary, higher CD34 cell dose is associated with better allo-HCT outcomes in MF and pre-HCT JAKi use is associated with reduced risk of severe aGVHD. These two modifiable parameters should be considered during allo-HCT for MF.

Thiotepa-busulfan-fludarabine (TBF) conditioning regimen in patients undergoing allogeneic hematopoietic cell transplantation for myelofibrosis: an outcome analysis from the Chronic Malignancies Working Party of the EBMT

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only curative option in MF. There is no consensus on the optimal conditioning regimen. We report outcomes of 187 patients with MF transplanted between 2010 and 2017 conditioned with TBF. Median age was 58 years. Median interval from diagnosis to allo-HCT was 44 months. Donors were haploidentical (41%), unrelated (36%) or HLA-identical siblings (23%). Stem cell source was PB in 60%. Conditioning was myeloablative in 48% of cases. Antithymocyte globulin (ATG) was used in 41% of patients. At 100 days, neutrophil and platelet engraftment were 91% and 63% after a median of 21 and 34 days, respectively. Grade II-IV and III-IV acute GVHD occurred in 24% and 12%, while at 3 years, all grade chronic GVHD and chronic extensive GVHD had been diagnosed in 38% and 11%. At 3 years, OS, RFS and GRFS were 55%, 49% and 43%, respectively. RI and NRM were 17% and 33%. On multivariate analysis, poor KPS and the use of unrelated donors were associated with worse GRFS and a higher grade II-IV acute GVHD, respectively. Neither donor type nor intensity of the conditioning regimen influenced survival outcomes. TBF is a feasible conditioning regimen in allo-HCT for MF in all donor settings although longer term outcomes are required.

Accelerated Phase of Myeloproliferative Neoplasms

BACKGROUND

Myeloproliferative neoplasms (MPNs) can transform into blast phase MPN (leukemic transformation; MPN-BP), typically via accelerated phase MPN (MPN-AP), in ∼20-25% of the cases. MPN-AP and MPN-BP are characterized by 10-19% and ≥20% blasts, respectively. MPN-AP/BP portend a dismal prognosis with no established conventional treatment. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the sole modality associated with long-term survival.

SUMMARY

MPN-AP/BP has a markedly different mutational profile from de novo acute myeloid leukemia (AML). In MPN-AP/BP, TP53 and IDH1/2 are more frequent, whereas FLT3 and DNMT3A are rare. Higher incidence of leukemic transformation has been associated with the most aggressive MPN subtype, myelofibrosis (MF); other risk factors for leukemic transformation include rising blast counts above 3-5%, advanced age, severe anemia, thrombocytopenia, leukocytosis, increasing bone marrow fibrosis, type 1 CALR-unmutated status, lack of driver mutations (negative for JAK2, CALR, or MPL genes), adverse cytogenetics, and acquisition of ≥2 high-molecular risk mutations (ASXL1, EZH2, IDH1/2, SRSF2, and U2AF1Q157). The aforementioned factors have been incorporated in several novel prognostic scoring systems for MF. Currently, elderly/unfit patients with MPN-AP/BP are treated with hypomethylating agents with/without ruxolitinib; these regimens appear to confer comparable benefit to intensive chemotherapy but with lower toxicity. Retrospective studies in patients who acquired actionable mutations during MPN-AP/BP showed positive outcomes with targeted AML treatments, such as IDH1/2 inhibitors, and require further evaluation in clinical trials. Key Messages: Therapy for MPN-AP patients represents an unmet medical need. MF patients, in particular, should be appropriately stratified regarding their prognosis and the risk for transformation. Higher-risk patients should be monitored regularly and treated prior to progression to MPN-BP. MPN-AP patients may be treated with hypomethylating agents alone or in combination with ruxolitinib; also, patients can be provided with the option to enroll in rationally designed clinical trials exploring combination regimens, including novel targeted drugs, with an ultimate goal to transition to transplant.

Ruxolitinib rechallenge in resistant or intolerant patients with myelofibrosis: Frequency, therapeutic effects, and impact on outcome

BACKGROUND

After ruxolitinib discontinuation, the outcome of patients with myelofibrosis (MF) is poor with scarce therapeutic possibilities.

METHODS

The authors performed a subanalysis of an observational, retrospective study (RUX-MF) that included 703 MF patients treated with ruxolitinib to investigate 1) the frequency and reasons for ruxolitinib rechallenge, 2) its therapeutic effects, and 3) its impact on overall survival.

RESULTS

A total of 219 patients (31.2%) discontinued ruxolitinib for ≥14 days and survived for ≥30 days. In 60 patients (27.4%), ruxolitinib was rechallenged for ≥14 days (RUX-again patients), whereas 159 patients (72.6%) discontinued it permanently (RUX-stop patients). The baseline characteristics of the 2 cohorts were comparable, but discontinuation due to a lack/loss of spleen response was lower in RUX-again patients (P = .004). In comparison with the disease status at the first ruxolitinib stop, at its restart, there was a significant increase in patients with large splenomegaly (P < .001) and a high Total Symptom Score (TSS; P < .001). During the rechallenge, 44.6% and 48.3% of the patients had spleen and symptom improvements, respectively, with a significant increase in the number of patients with a TSS reduction (P = .01). Although the use of a ruxolitinib dose > 10 mg twice daily predicted better spleen (P = .05) and symptom improvements (P = .02), the reasons for/duration of ruxolitinib discontinuation and the use of other therapies before rechallenge were not associated with rechallenge efficacy. At 1 and 2 years, 33.3% and 48.3% of RUX-again patients, respectively, had permanently discontinued ruxolitinib. The median overall survival was 27.9 months, and it was significantly longer for RUX-again patients (P = .004).

CONCLUSIONS

Ruxolitinib rechallenge was mainly used in intolerant patients; there were clinical improvements and a possible survival advantage in many cases, but there was a substantial rate of permanent discontinuation. Ruxolitinib rechallenge should be balanced against newer therapeutic possibilities.

Ruxolitinib before allogeneic hematopoietic transplantation in patients with myelofibrosis on behalf SFGM-TC and FIM groups

This multicenter prospective phase 2 trial analyzed disease-free survival (DFS) in myelofibrosis patients receiving ruxolitinib for 6 months before transplantation. Seventy-six patients were recruited. Age-adjusted dynamic international prognostic scoring system was intermediate-1, intermediate-2, and high in 27 (36%), 31 (41%), and 18 (24%) patients. All patients received ruxolitinib from inclusion to conditioning regimen (fludarabine-melphalan) or to progression. A donor was found in 64 patients: 18 HLA-matched sibling donor (MSD), 32 HLA-matched unrelated (UD10/10), and 14 HLA mismatched unrelated donor (UD9/10. Among 64 patients with a donor, 20 (31%) achieved a partial response before transplantation and 59 (92%) could be transplanted after ruxolitinib therapy (18/18 MSD, 30/21 UD10/10, 11/34 UD9/10), of whom 19 (32%) were splenectomized. Overall survival from inclusion was 68% at 12 months. One-year DFS after transplantation was 55%: 83%, 40%, and 34% after MSD, UD10/10 or UD9/10, respectively. Cumulative incidence of grade 2–4 acute graft-versus-host disease (GVHD) was 66% and non-relapse-mortality was 42% at 12 months. Short course of ruxolitinib before transplantation is followed by a high rate of transplantation. With the platform used in this protocol, outcome was much better in patients transplanted with HLA-matched sibling donor as compared to unrelated donor.

Application of Stem Cell Therapy in Myelofibrosis

Myelofibrosis (MF) belongs to a group of clonal stem cell disorders known as the BCR-ABL-negative myeloproliferative neoplasms. Allogeneic hematopoietic stem cell transplantation (HCT) is currently the only curative treatment option for MF. Because HCT can be associated with significant morbidity and mortality, patients need to be carefully selected based on disease-risk, fitness, and transplant factors. Furthermore, in the era of JAK inhibitors, the timing of transplantation has become a challenging question. Here the authors review recent developments in HCT for MF, focusing on risk stratification and optimal timing.

Diagnosis and prognosis are supported by integrated assessment of next-generation sequencing in chronic myeloid malignancies. A real-life study

Next-generation sequencing (NGS) is used to investigate the presence of somatic mutations. The utility of incorporating routine sequencing to guide diagnosis and therapeutic decisions remains unclear. We report the findings of an observational, multicenter study that aimed to assess the impact of somatic mutation testing by NGS in a reallife setting of chronic myeloid malignancies. A total of 177 patients were enrolled, partitioned into two overlapping groups. In group A (n=94), the indication was to search for clonal hematopoiesis, in a context of suspected myelodysplastic syndrome or myeloproliferative neoplasia. In group B (n=95), the theranostic impact of somatic mutations was studied. A panel of 34 genes was used on DNA extracted from blood or bone marrow samples. Within group A, the detection of clonal hematopoiesis supported the diagnosis of chronic myeloid malignancies for 31 patients while the absence of clonal hematopoiesis ruled out the suspected diagnosis in 47 patients. Within group B, NGS identified prognostically relevant somatic mutations in 32 patients, which had a therapeutic impact in 18 cases. By determining the presence or absence of somatic mutations, the application of NGS in daily practice was found to be useful for an integrated final diagnosis in 83% of the patients. Moreover, the search for somatic mutations had a prognostic impact that led to treatment modification in 19% of the cases. This study outlines the fact that adequate implementation of new investigations may have a significant positive medico-economic impact by enabling appropriate management of patients.

Clinical Significance of Bone Marrow Blast Percentage in Patients With Myelofibrosis and the Effect of Ruxolitinib Therapy

BACKGROUND

The effect of bone marrow (BM) blasts on the outcome of patients with myelofibrosis (MF) is poorly understood, unless they are ≥ 10% and represent a more aggressive accelerated phase. Similarly, the role of the JAK inhibitor, ruxolitinib (RUX), has not been assessed in correlation with BM blasts.

PATIENTS AND METHODS

Herein, we present clinical characteristics and outcomes of 1412 patients with MF stratified by BM blasts and therapy.

RESULTS

Seven percent and 4% of patients had 5% to 9% and ≥ 10% BM blasts, respectively. Forty-four percent of patients were treated with RUX throughout their disease course. Overall survival (OS) differed among patients with 0% to 1%, 2% to 4%, and 5% to 9% BM blasts, with median OS of 64, 48, and 22 months, respectively (P < .001). Patients with 5% to 9% BM blasts had similar OS as patients with ≥ 10% BM blasts (22 vs. 14 months; P = .73). All patients with < 10% blasts who were treated with RUX showed superior OS to patients who did not receive RUX.

CONCLUSIONS

Our results indicate that patients with MF with ≥ 5% BM blasts represent a high-risk group with adverse clinical characteristics and inferior outcome. However, they still appear to derive substantial survival benefit from therapy with RUX.

The 2020 revision of the guidelines for the management of myeloproliferative neoplasms

In 2016, the World Health Organization revised the diagnostic criteria for myeloproliferative neoplasms (MPNs) based on the discovery of disease-driving genetic aberrations and extensive analysis of the clinical characteristics of patients with MPNs. Recent studies have suggested that additional somatic mutations have a clinical impact on the prognosis of patients harboring these genetic abnormalities. Treatment strategies have also advanced with the introduction of JAK inhibitors, one of which has been approved for the treatment of patients with myelofibrosis and those with hydroxyurea-resistant or intolerant polycythemia vera. Recently developed drugs aim to elicit hematologic responses, as well as symptomatic and molecular responses, and the response criteria were refined accordingly. Based on these changes, we have revised the guidelines and present the diagnosis, treatment, and risk stratification of MPNs encountered in Korea.

The Genetic Basis of Primary Myelofibrosis and Its Clinical Relevance

Among classical BCR-ABL-negative myeloproliferative neoplasms (MPN), primary myelofibrosis (PMF) is the most aggressive subtype from a clinical standpoint, posing a great challenge to clinicians. Whilst the biological consequences of the three MPN driver gene mutations (JAK2, CALR, and MPL) have been well described, recent data has shed light on the complex and dynamic structure of PMF, that involves competing disease subclones, sequentially acquired genomic events, mostly in genes that are recurrently mutated in several myeloid neoplasms and in clonal hematopoiesis, and biological interactions between clonal hematopoietic stem cells and abnormal bone marrow niches. These observations may contribute to explain the wide heterogeneity in patients' clinical presentation and prognosis, and support the recent effort to include molecular information in prognostic scoring systems used for therapeutic decision-making, leading to promising clinical translation. In this review, we aim to address the topic of PMF molecular genetics, focusing on four questions: (1) what is the role of mutations on disease pathogenesis? (2) what is their impact on patients' clinical phenotype? (3) how do we integrate gene mutations in the risk stratification process? (4) how do we take advantage of molecular genetics when it comes to treatment decisions?

Second primary malignancy in myelofibrosis patients treated with ruxolitinib

Ruxolitinib (RUX), the first JAK1/JAK2 inhibitor approved for myelofibrosis (MF) therapy, has recently been associated with the occurrence of second primary malignancies (SPMs), mainly lymphomas and non-melanoma skin cancers (NMSCs). We analyzed the incidence, risk factors and outcome of SPMs in 700 MF patients treated with RUX in a real-world context. Median follow-up from starting RUX was 2·9 years. Overall, 80 (11·4%) patients developed 87 SPMs after RUX start. NMSCs were the most common SPMs (50·6% of the cases). Multivariate analysis demonstrated that male sex [hazard ratio (HR): 2·37, 95% confidence interval (95%CI): 1·22-4·60, P = 0·01] and thrombocytosis> 400 × 10⁹ /l at RUX start (HR:1·98, 95%CI: 1·10-4·60, P = 0·02) were associated with increased risk for SPMs. Risk factors for NMSC alone were male sex (HR: 3·14, 95%CI: 1·24-7·92, P = 0·02) and duration of hydroxycarbamide and RUX therapy > 5 years (HR: 3·20, 95%CI: 1·17-8·75, P = 0·02 and HR: 2·93, 95%CI: 1·39-6·17, P = 0·005 respectively). In SPMs excluding NMSCs, male sex (HR: 2·41, 95%CI: 1·11-5·25, P = 0·03), platelet > 400 × 10⁹ /l (HR: 3·30, 95%CI: 1·67-6·50, P = 0·001) and previous arterial thromboses (HR: 3·47, 95%CI: 1·48-8·14, P = 0·004) were shown to be associated with higher risk of SPMs. While it is reassuring that no aggressive lymphoma was documented, active skin surveillance is recommended in all patients and particularly after prolonged hydroxycaramide therapy; oncological screening should be triggered by thrombocytosis and arterial thrombosis, particularly in males.

Interferon Therapy in Myelofibrosis: Systematic Review and Meta-analysis

BACKGROUND

Myelofibrosis (MF) is a Philadelphia chromosome-negative myeloproliferative neoplasm characterized by progressive bone marrow failure, increased risk of progression to acute myeloid leukemia, and constitutional symptoms. For over 3 decades, various formulations of interferon (IFN) have been used for the treatment of MF, with variable results, and the role of IFN in the treatment of MF is evolving.

PATIENTS AND METHODS

For this systematic review and meta-analysis, Medline and Embase via Ovid, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science were searched from inception through March 2019 for studies of pegylated IFN (peg-IFN) and non-peg-IFN in MF patients. The primary outcome of overall response rate was defined as a composite of complete response, partial response, complete hematologic response, and partial hematologic response. Random-effects models were used to pool overall response rate, and metaregression analyses were performed to compare peg-IFN and non--peg-IFN formulations.

RESULTS

Among the 10 studies with 141 MF patients included, the overall response rate was 49.9% (95% confidence interval [CI], 30.4-69.3), and there was no statistically significant difference (P = .99) between peg-IFN (50.0%; 95% CI, 26.2-73.9; I2 = 76.9%) and non-peg-IFN (49.6%; 95% CI, 20.5-79.0; I2 = 56.7%). Treatment discontinuation resulting from adverse events was common with non-peg-IFN at 35.8% (95% CI, 3.5-68.1) per year, and less in the one study on peg-IFN (0.5% per year).

CONCLUSION

IFN can lead to hematologic improvements in a subset of MF patients, but study quality is limited and heterogenous. Biomarkers predicting response to IFN and formulations with improved tolerability are needed.

Prognostic value of blasts in peripheral blood in myelofibrosis in the ruxolitinib era

BACKGROUND

Circulating blasts (peripheral blood [PB] blasts) ≥1% have long been considered an unfavorable feature for patients with primary myelofibrosis. Whether further quantification of PB blasts and their correlation with bone marrow (BM) blasts have incremental value with regard to patient prognostication is unclear. Similarly, the role of the JAK1/JAK2 inhibitor ruxolitinib (RUX) is not well defined in patients who have increased blasts.

METHODS

The authors retrospectively studied 1316 patients with myelofibrosis who presented at their institution between 1984 and 2018 and had available PB and BM blasts.

RESULTS

The PB blast percentage influenced overall survival (OS) only among patients who had BM blasts <5%, with a median OS of 64 months for patients with 0% PB blasts, 48 months for those with 1% to 3% PB blasts, and 22 months for those with 4% PB blasts (P < .01). Patients who had 4% PB blasts and 5% to 9% BM/PB blasts had clinical features similar to those of patients who had 10% to 19% blasts. Although the OS of the former patients was longer than in patients who had 10% to 19% blasts, it was not statistically different (median OS: 22, 26, and 13 months, respectively; P > .05). Forty-four percent of patients received RUX throughout their disease course. All patients who had <10% blasts (PB or BM) and received treatment with RUX had superior OS compared with those who did not receive RUX within the same group. PB blasts ≥4% and BM blasts ≥5% were significant for predicting inferior survival in multivariate analysis.

CONCLUSIONS

The current results provide comprehensive insight into the role of peripheral blasts in patients with myelofibrosis and indicates that patients who have PB blasts ≥4% have an unfavorable prognosis. RUX provides a survival benefit to patients who have PB blasts <10%.

Organ Stiffness in the Work-Up of Myelofibrosis and Philadelphia-Negative Chronic Myeloproliferative Neoplasms

To define the role of spleen stiffness (SS) and liver stiffness (LS) in myelofibrosis and other Philadelphia (Ph)-negative myeloproliferative neoplasms (MPNs), we studied, by ultrasonography (US) and elastography (ES), 70 consecutive patients with myelofibrosis (MF) (no.43), essential thrombocythemia (ET) (no.10), and polycythemia vera (PV) (no.17). Overall, the median SS was not different between patients with MF and PV (p = 0.9); however, both MF and PV groups had significantly higher SS than the ET group (p = 0.011 and p = 0.035, respectively) and healthy controls (p < 0.0001 and p = 0.002, respectively). In patients with MF, SS values above 40 kPa were significantly associated with worse progression-free survival (PFS) (p = 0.012; HR = 3.2). SS also correlated with the extension of bone marrow fibrosis (BMF) (p < 0.0001). SS was higher in advanced fibrotic stages MF-2, MF-3 (W.H.O. criteria) than in pre-fibrotic/early fibrotic stages (MF-0, MF-1) (p < 0.0001) and PFS was significantly different in the two cohorts, with values of 63% and 85%, respectively (p = 0.038; HR = 2.61). LS significantly differed between the patient cohort with MF and healthy controls (p = 0.001), but not between the patient cohorts with ET and PV and healthy controls (p = 0.999 and p = 0.101, respectively). We can conclude that organ stiffness adds valuable information to the clinical work-up of MPNs and could be employed to define patients at a higher risk of progression.

JAK2, CALR, and MPL Mutations in Egyptian Patients With Classic Philadelphia-negative Myeloproliferative Neoplasms

BACKGROUND

Genetic mutations have been proven to be one of the major criteria in the diagnosis and distinction of different myeloproliferative neoplasm (MPN) subtypes. Therefore, the aim of this study was to determine the molecular profile of Egyptian patients with MPN subtypes and correlate with clinicopathological status.

METHODS

A series of 200 patients with MPNs (92 polycythemia vera, 68 essential thrombocythemia, and 40 primary myelofibrosis) were included in this study. DNA from each sample was amplified using polymerase chain reaction to detect Janus kinase 2 (JAK2), calreticulin (CALR), and myeloproliferative leukemia virus oncogene (MPL) mutations. Sanger sequencing was used to determine the mutation types.

RESULTS

Of the 200 samples, 44% had JAK2V617F and 10% were carrying CALR mutation with type 2 being the most frequent type in this study (55%). No MPL or JAK2 exon 12 mutations were detected. All clinical and hematological data had no differences with other populations except that our CALR-positive patients showed a decrease in the platelet count compared with JAK2V617F-positive patients.

CONCLUSION

Our study on Egyptian patients shows a specific molecular profile of JAK2 mutation, and CALR mutation type 2 was higher than type 1.

Healthcare resource utilization in myeloproliferative neoplasms: a population-based study from Ontario, Canada

Health resource utilization (HRU) and associated factors of high cost are not well understood in myeloproliferative neoplasms (MPNs). In this population-based, retrospective matched-cohort study, we used administrative health databases of Ontario, Canada to measure treatment costs and HRU for patients with MPN from 2004 to 2016 and compared them to matched controls. In 7130 patients with MPN [essential thrombocythemia (ET) = 3481; polycythemia vera (PV) = 2618; myelofibrosis (MF) = 1031], the mean annualized treatment costs were $16,646 for ET (controls, $7070); $16,360 for PV (controls, $7293); and $25,863 for MF (controls, $7386). Out of the total costs, the largest expenditure was on acute hospital care (ET: 57%, PV: 57%, MF: 66%). Older age (≥65), male gender, patients not seen by a specialist, and greater comorbidity burden were independent predictors of higher costs (p < 0.05). In addition, history of venous thrombosis in patients with ET and PV was associated with significantly higher treatment costs (p < 0.05).

Risk factors for progression to blast phase and outcome in 589 patients with myelofibrosis treated with ruxolitinib: Real-world data

The impact of ruxolitinib therapy on evolution to blast phase (BP) in patients with myelofibrosis (MF) is still uncertain. In 589 MF patients treated with ruxolitinib, we investigated incidence and risk factors for BP and we described outcome according to disease characteristics and treatment strategy. After a median follow-up from ruxolitinib start of 3 years (range 0.1-7.6), 65 (11%) patients transformed to BP during (93.8%) or after treatment. BP incidence rate was 3.7 per 100 patient-years, comparably in primary and secondary MF (PMF/SMF) but significantly lower in intermediate-1 risk patients (2.3 vs 5.6 per 100 patient-years in intermediate-2/high-risk patients, P < .001). In PMF and SMF cohorts, previous interferon therapy seemed to correlate with a lower probability of BP (HR 0.13, P = .001 and HR 0.22, P = .02, respectively). In SMF, also platelet count <150 × 10⁹ /l (HR 2.4, P = .03) and peripheral blasts ≥3% (HR 3.3, P = .004) were significantly associated with higher risk of BP. High-risk category according to dynamic International Prognostic Score System (DIPSS) and myelofibrosis secondary to PV and ET Collaboration Prognostic Model (MYSEC-PM predicted BP in patients with PMF and SMF, respectively. Median survival after BP was 0.2 (95% CI: 0.1-0.3) years. Therapy for BP included hypomethylating agents (12.3%), induction chemotherapy (9.2%), allogeneic transplant (6.2%) or supportive care (72.3%). Patients treated with supportive therapy had a median survival of 6 weeks, while 73% of the few transplanted patients were alive at a median follow-up of 2 years. Progression to BP occurs in a significant fraction of ruxolitinib-treated patients and is associated with DIPSS and MYSEC-PM risk in PMF and SMF, respectively.

Clonal Evolution after Allogeneic Hematopoietic Stem Cell Transplantation: The Case of Myelofibrosis

The significance of clonal evolution in myelofibrosis (MF) relapse remains poorly understood. Here we performed panel sequencing in paired samples of 30 patients with MF who relapsed after undergoing allogeneic hematopoietic stem cell transplantation (alloSCT). We identified a median of 2 mutations (range, 0 to 12) in a median of 2 genes (range, 0 to 8) before allo-SCT, along with a median of 2 mutations (range, 0 to 12) in 2 genes (range, 0 to 6) at relapse. Additional whole-genome sequencing (n = 6) did not elucidate additional molecular changes. Taken together, our data provide further evidence, here on MF, that clonal evolution after alloSCT is limited and that instead, alloSCT selects specific (sub)clones.

Thrombocytopenia in patients with myelofibrosis: management options in the era of JAK inhibitor therapy

Myelofibrosis (MF), either appearing de novo (primary MF, PMF) or after a previous diagnosis of essential thrombocythemia or of polycythemia vera, is a progressive disease burdened by symptomatic splenomegaly, debilitating systemic symptoms, ineffective hematopoiesis, and overall reduced survival. Patients often present worsening cytopenias, including thrombocytopenia, secondary to progression of the disease as well as to cytoreductive treatment. Patients with MF and thrombocytopenia have few therapeutic options and there is limited information regarding the management of disease in these settings. This article reviews current evidence for the management of patients with MF and thrombocytopenia, in the era of JAK inhibitors.

Clinico-biological characteristics of patients with myelofibrosis: an analysis of 1,000 cases from the Spanish Registry of Myelofibrosis

BACKGROUND AND OBJECTIVE MYELOFIBROSIS: is an infrequent chronic myeloproliferative neoplasm. We aimed to describe the clinico-biological characteristics, treatment, and evolutive course of myelofibrosis patients in Spain.

MATERIAL AND METHODS

A total of 1,000 patients from the Spanish Registry of Myelofibrosis diagnosed with primary (n=641) or secondary (n=359) myelofibrosis were analysed.

RESULTS

Median age was 68 years. The frequency of constitutional symptoms, moderate to severe anaemia (Hb<10g/dL), and symptomatic splenomegaly was 35%, 36%, and 17%, respectively. The rate of thrombosis and haemorrhage was 1.96 and 1.6 events per 100 patient-years, respectively. The cumulative incidence of leukaemia at 10 years was 15%. The most frequent therapies for the anaemia were the erythropoiesis stimulating agents and danazol. From 2010, a progressive increase in the use of ruxolitinib was noticed. A total of 7.5% of patients were transplanted. During the observation period, 42% of patients died mainly due to the clinical deterioration caused by myelofibrosis or leukaemic transformation. The median survival of the series was 5.7 years. Four different risk categories were identified by the IPSS: median survival was not reached in the low risk group and was 8.8 years, 5.3 years, and 2.8 years in the intermediate-1, intermediate-2, and high-risk groups, respectively.

CONCLUSIONS

Myelofibrosis is a disabling condition mainly affecting elderly people. Its treatment is mostly driven by symptom control. Despite its clinical heterogeneity, several prognostic models are useful to select candidates for transplantation.

Targeted molecular characterization shows differences between primary and secondary myelofibrosis

INTRODUCTION

In BCR-ABL1-negative myeloproliferative neoplasms, myelofibrosis (MF) is either primary (PMF) or secondary (SMF) to polycythemia vera or essential thrombocythemia. MF is characterized by an increased risk of transformation to acute myeloid leukemia (AML) and a shortened life expectancy.

METHODS

Because natural histories of PMF and SMF are different, we studied by targeted next generation sequencing the differences in the molecular landscape of 86 PMF and 59 SMF and compared their prognosis impact.

RESULTS

PMF had more ASXL1 (47.7%) and SRSF2 (14%) gene mutations than SMF (respectively 27.1% and 3.4%, P = .04). Poorer survival was associated with RNA splicing mutations (especially SRSF2) and TP53 in PMF (P = .0003), and with ASXL1 and TP53 mutations in SMF (P < .0001). These mutations of poor prognosis were associated with biological features of scoring systems (DIPSS and MYSEC-PM score). Mutations in TP53/SRSF2 in PMF or TP53/ASXL1 in SMF were more frequent as the risk of these scores increased. This allowed for a better stratification of MF patients, especially within the DIPSS intermediate-1 risk group (DIPSS) or the MYSEC-PM high risk group. AML transformation occurred faster in SMF than in PMF and patients who transformed to AML were more SRSF2-mutated and less CALR-mutated at MF sampling.

CONCLUSIONS

PMF and SMF have different but not specific molecular profiles and different prognosis depending on the molecular profile. This may be due to differences in disease history. Combining mutations and existing scores should improve prognosis assessment.

Life after ruxolitinib: Reasons for discontinuation, impact of disease phase, and outcomes in 218 patients with myelofibrosis

BACKGROUND

After discontinuing ruxolitinib, the outcome of patients with myelofibrosis reportedly has been poor. The authors investigated whether disease characteristics before the receipt of ruxolitinib may predict drug discontinuation in patients with myelofibrosis and whether reasons for drug discontinuation, disease phase at discontinuation, and salvage therapies may influence the outcome.

METHODS

A centralized electronic clinical database was created in 20 European hematology centers, including clinical and laboratory data for 524 patients who received ruxolitinib for myelofibrosis.

RESULTS

At 3 years, 40.8% of patients had stopped ruxolitinib. Baseline predictors of drug discontinuation were: intermediate-2-risk/high-risk category (Dynamic International Prognostic Score System), a platelet count <100 ×10⁹ per liter, transfusion dependency, and unfavorable karyotype. At last contact, 268 patients (51.1%) had discontinued therapy, and the median drug exposure was 17.5 months. Fifty patients (18.7%) died while taking ruxolitinib. The reasons for discontinuation in the remaining 218 patients were the lack (22.9%) or loss (11.9%) of a spleen response, ruxolitinib-related adverse events (27.5%), progression to blast phase (23.4%), ruxolitinib-unrelated adverse events (9.2%), and allogeneic transplantation during response (5.1%). The median survival after ruxolitinib was 13.2 months and was significantly better in the 167 patients who discontinued ruxolitinib in chronic phase (27.5 vs 3.9 months for those who discontinued in blast phase; P < .001). No survival differences were observed among patients who discontinued ruxolitinib in chronic phase because of lack of response, loss of response, or ruxolitinib-related adverse events. The use of investigational agents and/or ruxolitinib rechallenge were associated with improved outcome.

CONCLUSIONS

The survival of patients with myelofibrosis after discontinuation of ruxolitinib is poor, particularly for those who discontinue in blast phase. Salvage therapies can improve outcome, emphasizing the need for novel therapies.

Assessment of Quality of Life following Allogeneic Stem Cell Transplant for Myelofibrosis

Patient-reported outcomes (PROs) for patients with myelofibrosis (MF) have been well characterized, but little is known about quality of life (QoL) following allogeneic stem cell transplantation (allo-SCT). Medical data and PRO measures were collected before transplant and at day 30, day 100, and 1 year after allo-SCT. PRO measures include Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF), Brief Fatigue Inventory, Global Assessment of Change, and Functional Assessment of Cancer Therapy-Bone Marrow Transplant. Forty-four patients who had baseline QoL and at least 1 post-transplant assessment were included. The median age of the patients was 62.5 years (range, 35 to 74 years). At baseline, the mean MPN Total Symptom Score was 28.0, and at day 30, day 100, and 1 year, it was 25.4, 32.3, and 24.3, respectively. However, in myeloproliferative neoplasm-specific symptoms, such as itching, night sweats, bone pain, and fever, a statistically significant improvement was observed for at least 1 time point following transplant. At day 30, 10 (26.3%) patients reported a little/moderately/very much better overall QoL since their transplant, and 26 (68.45%) had a little/moderately/very much worse QoL. At day 100, 10 (30.3%) reported better QoL and 19 (57.6%) reported worsening since transplant. By 1 year, 16 (61.5%) reported feeling better. Our study shows that there is very little change in symptom burden at 1 year following transplant in general, but MF-specific symptoms showed improvement. By 1 year, 61% felt that their QoL was better than it was before transplant.

Myeloproliferative Neoplasms: A Primer for Radiologists

The myeloproliferative neoplasms (MPNs) are a heterogeneous group of diseases including polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Knowledge of the radiological and clinical features of MPNs and their associated complications is critical for interpreting radiologists. The purpose of this article is to provide a primer to radiologists summarizing the modern understanding of MPNs from an imaging-based perspective, including common disease-related findings and complications related to hematopoietic cell transplant.

Clinical considerations for the use of FLT3 inhibitors in acute myeloid leukemia

Internal tandem duplications and tyrosine kinase mutations in the fms-like tyrosine kinase 3 (FLT3) receptor can occur in acute myeloid leukemia (AML) and portend a poor prognosis. Midostaurin, a multikinase inhibitor that targets FLT3, demonstrated a survival benefit in FLT3-mutated AML in combination with front-line chemotherapy. Despite this advancement, the use of FLT3 inhibitors in clinical practice is complicated by significant drug-drug interactions and uncertainty about optimal timing, duration, and sequencing of therapy. As monotherapy, the utility of FLT3 inhibitors was initially limited by incomplete and transient clinical responses and the development of acquired resistance. This led to the development of more potent and selective FLT3 inhibitors designed to overcome common resistance mechanisms. One of these second generation FLT3 inhibitors, gilteritinib, is now FDA-approved for the treatment of relapsed or refractory AML. Now that multiple FLT3 inhibitors are commercially available, it is important to further delineate the role of these agents in the AML population. This review aims to provide a comprehensive overview of the role of FLT3 inhibitors in AML and apply the current literature to clinical practice.

Impact of 2016 WHO diagnosis of early and overt primary myelofibrosis on presentation and outcome of 232 patients treated with ruxolitinib

The 2016 WHO criteria identified early primary myelofibrosis (PMF) as an individual entity with milder clinical features and better outcome compared with overt PMF. Here, we compared early and overt PMF patients treated with ruxolitinib in terms of baseline clinical/laboratory characteristics, response, and toxicity to treatment. We observed that early-PMF patients achieve better and more stable spleen and symptoms responses, with significantly lower rates of hematological toxicities. No differences in overall and leukemia-free survival were detected between the two cohorts. The application of 2016 WHO criteria is crucial to identify those PMF patients who deserve a stricter monitoring during treatment.

Reduced intensity allogeneic stem cell transplantation for younger patients with myelofibrosis

Allogeneic stem cell transplantation (alloSCT) is a curative procedure for myelofibrosis. Elderly people are mainly affected, limiting the feasibility of myeloablative regimens. The introduction of reduced-intensity conditioning (RIC) made alloSCT feasible for older patients. Nevertheless, the incidence of myelofibrosis is not negligible in young patients, who are theoretically able to tolerate high-intensity therapy. Very few data are available about the efficacy of RIC-alloSCT in younger myelofibrosis patients. This study included 56 transplanted patients aged <55 years. Only 30% had a human leucocyte antigen (HLA)-matched sibling donor, the others were transplanted from a fully-matched (36%) or partially-matched (34%) unrelated donor. All transplants were conditioned according the European Society for Blood and Marrow Transplantation protocol: busulfan-fludarabine + anti-thymocyte globulin, followed by ciclosporin and mycophenolate. One patient experienced primary graft failure. Incidence of graft-versus-host disease grade II-IV was 44% (grade III/IV 23%). One-year non-relapse mortality was 7% and the 5-year cumulative incidence of relapse was 19%. After a median follow-up of 8·6 years, the estimated 5-year progression-free survival and overall survival (OS) was 68% and 82%, respectively. Patients with fully-matched donor had a 5-year OS of 92%, in contrast to 68% for those with a mismatched donor (P = 0·03). The most important outcome-determining factor is donor HLA-matching. In conclusion, RIC-alloSCT ensures optimal engraftment and low relapse rate in younger myelofibrosis patients, enabling the possibility of cure in this group.

The germline JAK2 GGCC (46/1) haplotype and survival among 414 molecularly-annotated patients with primary myelofibrosis

JAK2 mutations in myeloproliferative neoplasms (MPNs) are associated with the germline GGCC (46/1) haplotype. In 2010, we reported an association between shortened survival in primary myelofibrosis (PMF) and nullizygosity for the JAK2 46/1 haplotype. In the current study, we have increased the number of informative cases from 130 to 414 (median age 63 years; 63% males), in order to revisit with the phenotypic and prognostic relevance of the JAK2 46/1 haplotype in PMF. JAK2 46/1 haplotype was documented in 69% of the study patients, including 25% in homozygous and 44% in heterozygous state. Driver mutation frequency in patients homozygous/heterozygous/nullizygous for the 46/1 haplotype was 78%/60%/56% JAK2, 10%/20%/18% type 1-like CALR, 3%/2%/5% type 2-like CALR, 4%/8%/7% MPL, and 6%/10%/14% triple-negative (P = .02). In univariate analysis, nullizygosity for the JAK2 46/1 haplotype was associated with inferior overall survival (HR 1.5, 95% CI 1.1-1.9), most pronounced in JAK2 (P <.001), as opposed to CALR/MPL mutated (P = .48) or triple-negative cases (P = .27). Multivariable analysis that included karyotype, driver mutational status and high-molecular risk mutations confirmed the independent prognostic contribution of nullizygosity for the 46/1 haplotype (P = .02; HR 1.4, 95% CI 1.1-1.8). Nullizygosity for 46/1 also remained significant in the context of the genetically-inspired GIPSS risk model (P = .04), but not in the context of the integrated genetics-clinical MIPSS70+ version 2.0 model (P = .4). Leukemia-free survival was not affected by the 46/1 haplotype (P = .6). The current study confirms the association of nullizygosity for the JAK2 GGCC (46/1) haplotype with inferior survival in JAK2-mutated PMF.