A prognostic model to predict survival after 6 months of ruxolitinib in patients with myelofibrosis

What are the therapeutic options for previously treated myelofibrosis?

INTRODUCTION

The disruption of the JAK/STAT signaling pathway is a defining feature of myelofibrosis (MF). The introduction of JAK inhibitors (JAKi) has transformed the therapeutic approach to MF, becoming essential to treatment and reshaping the management landscape. While JAKi are now the preferred first-line treatment for most patients, various management options are available for those who do not respond to initial therapy.

AREAS COVERED

This review focuses on management options for patients with MF, with particular emphasis on therapeutic strategies following the failure of first-line JAKi. It provides a comprehensive overview of the current treatment landscape, including alternative JAKi and other approaches. The review is based on an extensive literature search using available databases (PubMed, Cochrane …) and relevant web resources (clinicaltrials.gov).

EXPERT OPINION

Ruxolitinib benefits in MF often diminish after 3-4 years, with complications like thrombocytopenia and anemia. Three newer JAKi offer alternatives with similar efficacy and varied side effects. Stem cell transplantation is a curative option for a minority, ideally timed at peak response to JAKi. Research aims to enhance first-line treatments and restore responses in resistant patients. Future therapies may include novel combinations or immunotherapies targeting specific mutations, requiring collaboration between patient, clinical, and pharmaceutical communities.

The Gordian knot: ruxolitinib or transplants for high-risk myelofibrosis

Not available.

Identifying disease-modifying potential in myelofibrosis clinical trials

ABSTRACT

The ultimate goal of bringing most new drugs to the clinic in hematologic malignancy is to improve overall survival. However, the use of surrogate end points for overall survival is increasingly considered standard practice, because a well validated surrogate end point can accelerate the outcome assessment and facilitate better clinical trial design. Established examples include monitoring minimal residual disease in chronic myeloid leukemia and acute leukemia, and metabolic response assessment in lymphoma. However, what happens when a clinical trial end point that is not a good surrogate for disease-modifying potential becomes ingrained as an expected outcome, and new agents are expected or required to meet this end point to demonstrate "efficacy"? Janus kinase (JAK) inhibitors for myelofibrosis (MF) have a specific impact on reducing symptom burden and splenomegaly but limited impact on the natural history of the disease. Since the introduction of ruxolitinib more than a decade ago there has been modest incremental success in clinical trials for MF but no major leap forward to alter the natural history of the disease. We argue that the clinical development of novel agents for MF will be accelerated by moving away from using end points that are specifically tailored to measure the beneficial effects of JAK inhibitors. We propose that specific measures of relevant disease burden, such as reduction in mutation burden as determined by molecular end points, should replace established end points. Careful reanalysis of existing data and trials in progress is needed to identify the most useful surrogate end points for future MF trials and better serve patient interest.

JAK Inhibitors for Myelofibrosis: Strengths and Limitations

PURPOSE OF REVIEW

The landscape of myelofibrosis (MF) has changed since the discovery of the JAK2 V617F mutation and subsequent development of JAK inhibitors (JAKis). However, treatment with JAKis remain a challenge. In this review we critically analyze the strengths and limitations of currently available JAK inhibitors.

RECENT FINDINGS

In MF patients, JAK inhibitors have been associated with reduced symptom burden and spleen size, as well as improved survival. However, durability of response and development of treatment resistance remain an issue. Recently, there has been increased efforts to optimize treatment with the development of highly selective JAK inhibitors, as well as use of combination agents to counter disease resistance through targeting aberrant signaling pathways. Treatment of MF patients with JAKi therapy can be challenging but the development of more potent and selective JAK inhibitors, as well as combination therapies, represent exciting treatment advances in this field.

Pacritinib Response Is Associated With Overall Survival in Myelofibrosis: PERSIST-2 Landmark Analysis of Survival

Spleen volume reduction (SVR) is a key endpoint in inhibitors of Janus kinase (JAK) inhibitor studies. Retrospective analyses have demonstrated an association between SVR and improved overall survival (OS) among patients treated with ruxolitinib with a platelet count > 100 × 109/L. Whether this association occurs in patients with thrombocytopenia is unclear. Pacritinib, a JAK2/IRAK1/ACVR1 inhibitor, demonstrated improved SVR versus best available therapy (BAT [best available therapy]; including ruxolitinib) in patients with myelofibrosis and platelet counts ≤ 100 × 109/L in the PERSIST-2 study. Patients on study at the start of the 12-week SVR window on pacritinib 200 mg twice daily or BAT were included. OS was evaluated among SVR responders versus non-responders using different SVR thresholds (≥ 35%, ≥ 20%, ≥ 10%, and > 0%). Among patients on pacritinib (n = 89), SVR ≥ 10% demonstrated the greatest separation in OS curves between responders and non-responders (HR, 0.00; 95% CI, 0.00-0.14; p < 0.01), though SVR ≥ 0% and SVR ≥ 20% were also associated with improved OS. No SVR threshold conferred OS benefit on BAT (n = 84), including ruxolitinib (n = 39). In patients with myelofibrosis and platelets ≤ 100 × 109/L, achieving SVR on pacritinib, but not BAT (including ruxolitinib), was associated with significant OS benefit, suggesting that pacritinib may offer a unique survival advantage in patients with myelofibrosis and thrombocytopenia who achieve any SVR. Trial Registration: ClinicalTrials.gov number: NCT02055781.

Ruxolitinib for myelofibrosis: The earlier, the better?

There is mounting evidence to support the use of ruxolitinib earlier in the disease course of myelofibrosis. Use in intermediate‐1 risk myelofibrosis is generally associated with higher efficacy and lower toxicity.

Janus kinase inhibitor monotherapy and combination therapies for myelofibrosis: what's the current standard of care?

INTRODUCTION

JAK inhibitors (JAKi) have changed the treatment paradigm of myelofibrosis (MF). Currently, 4 JAKis are approved in the US as monotherapy (mono) to treat patients with MF. JAKis are also being studied in combination (combo) with novel agents. Herein, we review some of the key studies that evaluated JAKi as mono and combo in MF.

AREAS COVERED

We performed a Pubmed search for 'JAK inhibitors' and 'myelofibrosis' from 1/2010 to 12/2023. For mono, we included only the unique phase II/III studies of the approved JAKi. Selective studies that evaluated JAKi in combo with the novel agents were also included.

EXPERT OPINION

JAKis aim to provide clinical benefit to patients via spleen size reduction and MPN symptom improvement. In order to potentially increase clinical benefit for patients with MF, several novel agents are being partnered with ruxolitinib (RUX) with the ongoing hypothesis to augment greater measures of MF disease modification. The novel agents are either 'added-on' to RUX or as a combo in JAKi naïve patients. Also, the mutant-targeting era of therapies is now beginning with novel CALR-mutated, novel JAK2 V617F mutation-specific and type II JAK2i in the initial stages of drug development, representing a new approach to treatment.

The impact of starting dose on overall survival in myelofibrosis patients treated with ruxolitinib: A prospective real-world study on AIFA monitoring registries

Ruxolitinib is a JAK1/JAK2 inhibitor approved for the treatment of myelofibrosis (MF)-related splenomegaly or symptoms. The recommended starting dose depends on platelet count, regardless of haemoglobin level at baseline. In the recent years, an overall survival (OS) advantage was reported in patients treated with ruxolitinib compared with best available therapy. We analysed a large Italian cohort of 3494 patients identified by Agenzia Italiana del Farmaco (AIFA) monitoring registries. Of them, 2337 (66.9%) started at reduced dose: these patients were older (median age 70 vs. 67), with increased incidence of large splenomegaly (longitudinal diameter 20 vs. 19.1 cm, median volume 1064 cm3 vs. 1016 cm3), with higher IPSS risk (30.9% vs. 26.1%), and worse ECOG score (more than 1 in 14.3% vs. 9.8%). After balancing for baseline characteristics, Kaplan-Meier analysis showed a median OS of 78.2 months (95% CI 65.9-89) for patients who started at full dose and 52.6 (95% CI 49-56.6) months for patients who started with reduced dose (p < 0.001). Group analysis also showed a substantial difference in patients with intermediate-2 and high IPSS risk. The majority of MF patients in real-world analysis started with a reduced dose of ruxolitinib, which is associated with less favourable outcomes.

Evaluating estimated health care resource utilization and costs in patients with myelofibrosis based on transfusion status and anemia severity: A retrospective analysis of the Medicare Fee-For-Service claims data

BACKGROUND

Myelofibrosis (MF) is a rare but aggressive myeloproliferative neoplasm that commonly affects older patients, with a mean age of onset of older than 60 years. At least a third of patients with primary MF are anemic at diagnosis, and nearly all patients become anemic over time; approximately half require red blood cell transfusions within a year of diagnosis. Anemia and transfusion dependence are leading negative prognostic factors for overall survival and are associated with diminished quality of life and increased health care-related economic burden in patients with MF.

OBJECTIVE

To describe baseline characteristics, health care resource utilization (HCRU), and costs as a function of transfusion status and anemia severity in patients diagnosed with MF among the US Medicare Fee-For-Service (FFS) population.

METHODS

This retrospective cohort study included patients diagnosed with MF appearing in the 100% Medicare FFS database enrolled between January 1, 2012, and December 31, 2020. Patients were segmented into hemoglobin level cohorts (no, mild, moderate, and severe anemia) and transfusion status cohorts (transfusion independent [TI], transfusion requiring [TR], or transfusion dependent [TD]). Across cohorts, demographics and disease characteristics were assessed at baseline; per patient per month all-cause HCRU and medical and pharmacy costs were reported during follow-up. All results were summarized descriptively.

RESULTS

The transfusion status cohort (N = 1,749) included TI (n = 980), TR (n = 559), and TD (n = 210) patients; the anemia severity cohort (N = 365) included patients with no (n = 100), mild (n = 128), moderate (n = 99), and severe (n = 38) anemia. On average, TR and TD patients or those with moderate or severe anemia had numerically higher Deyo-Charlson Comorbidity Index scores than those who were TI or had mild or no anemia. TR and TD cohorts reported numerically greater all-cause outpatient, inpatient, and emergency department utilization vs the TI cohort. All-cause costs were numerically higher in the TD and TR cohorts vs the TI cohort ($14,655 and $14,249 vs $8,191). Incremental increases in HCRU and costs were also observed with increasing anemia severity. All-cause medical and pharmacy costs for no, mild, moderate, and severe anemia cohorts were $4,689, $7,268, $10,439, and $13,590, respectively.

CONCLUSIONS

This retrospective analysis of the US Medicare FFS database descriptively evaluated patients by transfusion status and anemia severity and showed that costs and HCRU were numerically lower for patients with transfusion independence compared with those with transfusion dependence. Similar trends were seen when comparing patients based on anemia status, with numerically lower HCRU and cost observed with decreasing anemia severity.

Prognostic and Predictive Models in Myelofibrosis

PURPOSE OF REVIEW

Myelofibrosis (MF) includes prefibrotic primary MF (pre-PMF), overt-PMF and secondary MF (SMF). Median overall survival (OS) of pre-PMF, overt-PMF and SMF patients is around 14 years, seven and nine years, respectively. Main causes of mortality are non-clonal progression and transformation into blast phase.

RECENT FINDINGS

Discoveries on the impact of the biological architecture on OS have led to the design of integrated scores to predict survival in PMF. For SMF, OS estimates should be calculated by the specific MYSEC-PM (MYelofibrosis SECondary-prognostic model). Information on the prognostic role of the molecular landscape in SMF is accumulating. Crucial treatment decisions for MF patients could be now supported by multivariable predictive algorithms. OS should become a relevant endpoint of clinical trials. Prognostic models guide prediction of OS and treatment planning in MF, therefore, their timely application is critical in the personalized approach of MF patients.

SOHO State of the Art Updates and Next Questions | Choosing and Properly Using a JAK Inhibitor in Myelofibrosis

Myelofibrosis (MF) is a chronic myeloid neoplasm characterized by myeloproliferation, bone marrow fibrosis, splenomegaly, and constitutional symptoms related to pro-inflammatory cytokine signaling. Biologically, MF is characterized by constitutive activation of JAK-STAT signaling; accordingly, JAK inhibitors have been rationally developed to treat MF. Following the initial approval of ruxolitinib in 2011, three additional agents have been approved: fedratinib, pacritinib, and momelotinib. As these therapies are noncurative, allogeneic stem cell transplantation remains a key treatment modality and patients with MF who are deemed candidates should be referred to a transplant center. This potentially curative but toxic approach is typically reserved for patients with higher-risk disease, and JAK inhibitors are recommended in the pretransplant setting. JAK inhibitors have proven effective at managing splenomegaly and constitutional symptoms and should be started early in the disease course in patients presenting with these clinical manifestations; asymptomatic patients may initially be followed with close surveillance. Drug-related myelosuppression has been a challenge with initial JAK inhibitors, particularly in patients presenting with a cytopenic phenotype. However, newer agents, namely pacritinib and momelotinib, have proven more effective in this setting and are approved for patients with significant thrombocytopenia and anemia, respectively. Resistance or disease progression is clinically challenging and may be defined by several possible events, such as increasing splenomegaly or progression to accelerated or blast phase disease. However, with multiple JAK inhibitors now approved, sequencing of these agents appears poised to improve outcomes. Additionally, novel JAK inhibitors and JAK inhibitor-based combinations are in clinical development.

Red cell distribution width and prognosis in myelofibrosis patients treated with ruxolitinib

We evaluated RDW in a single-center series of 61 consecutive patients with primary and secondary MF at diagnosis and during treatment with ruxolitinib (RUX) and examined any possible prognostic impact. Elevated RDW values were present in all but 4 patients at diagnosis with a median RDW of 18.9%. RDW was higher in subjects with palpable splenomegaly (p = 0.02), higher ferritin, as well as among those cases who did not receive any cytoreduction before RUX (p = 0.04). Interestingly, higher RDW at diagnosis also correlated with a shorter time from MF diagnosis to RUX start (-4.1 months per one RDW unit; p = 0.03). We observed a modest increase (< 1%) in RDW during the first 6 months of RUX treatment. In a multivariable random-intercept model that considered all time points and contained the covariates time and RUX dose, we also observed a clear decrease in RDW with increasing hemoglobin (Hb) during RUX (slope: -0.4% per g/dL of Hb; p < 0.001). The median RDW at diagnosis of 18.9% was used as a cut-off to identify two subgroups of patients [Group 1: RDW 19.0-25.7%; Group 2: RDW 13.1-18.7%], showing a difference in mortality [Group 1 vs. 2: crude HR 2.88; p = 0.01]. Using continuous RDW at diagnosis, the crude HR was 1.21 per RDW unit (p = 0.002). In a Cox model adjusted for gender, age and Hb at diagnosis, the HR was 1.13 per RDW unit (p = 0.07). RDW may have prognostic significance at MF diagnosis and during RUX, helping in the rapid detection of patients with poor prognosis.

Transfusion-related cost offsets and time burden in patients with myelofibrosis on momelotinib vs. danazol from MOMENTUM

Aim: To estimate projected US-based cost and time burden for patients with myelofibrosis and anemia treated with momelotinib compared with danazol.Methods: Cost and time burden were calculated based on the transfusion status of patients in the MOMENTUM trial and estimates extracted from previous studies.Results: Reductions in transfusion associated with momelotinib are projected to result in cost and time savings compared with danazol in transfusion-dependent and transfusion-independent/requiring patients with myelofibrosis, respectively: annual medical costs ($53,143 and $46,455 per person), outpatient transfusion costs ($42,021 and $8,370 per person) and annual time savings (173 and 35 h per person).Conclusion: Fewer transfusions with momelotinib are projected to result in cost and time savings in patients with myelofibrosis and anemia compared with danazol.

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.

Advances with janus kinase inhibitors for the treatment of myeloproliferative neoplasms: an update of the literature

INTRODUCTION

The hallmark discovery of hyperactivation of the janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway was a sentinel moment in the history of myeloproliferative neoplasms (MPNs). This finding paved the way for the development of JAK inhibitors, which now represent the foundation of myelofibrosis therapy. With four JAK inhibitors now approved for myelofibrosis, awareness of their clinical efficacy and safety data and recognition of their unique pharmacologic attributes are of critical importance. Additionally, ruxolitinib represents an integral part of the therapeutic arsenal for polycythemia vera.

AREAS COVERED

This review provides a broad overview of the published literature supporting JAK inhibitor therapy for MPNs. Primarily focusing on myelofibrosis, each of the four available JAK inhibitors is reviewed in detail, including pharmacology, efficacy, and safety data. Failure of JAK inhibitors and future directions in JAK inhibitor therapy are also discussed.

EXPERT OPINION

JAK inhibitors revolutionized the treatment of MPNs and have dramatically improved patient outcomes. However, data informing selection between currently available JAK inhibitors is limited. These agents are not curative and eventually fail most patients with myelofibrosis. Combining JAK inhibitors with novel targeted agents appears to be the most promising path to further improve outcomes.

Myelofibrosis and allogeneic transplantation: critical points and challenges

New available drugs allow better control of systemic symptoms associated with myelofibrosis (MF) and splenomegaly but they do not modify the natural history of progressive and poor prognosis disease. Thus, hematopoietic stem cell transplantation (HSCT) is still considered the only available curative treatment for patients with MF. Despite the increasing number of procedures worldwide in recent years, HSCT for MF patients remains challenging. An increasingly complex network of the patient, disease, and transplant-related factors should be considered to understand the need for and the benefits of the procedure. Unfortunately, prospective trials are often lacking in this setting, making an evidence-based decision process particularly arduous. In the present review, we will analyze the main controversial points of allogeneic transplantation in MF, that is, the development of more sophisticated models for the identification of eligible patients; the need for tools offering a more precise definition of expected outcomes combining comorbidity assessment and factors related to the procedure; the decision-making process about the best transplantation time; the evaluation of the most appropriate platform for curative treatment; the impact of splenomegaly; and splenectomy on outcomes.

Management of Patients with Early Myelofibrosis: A Discussion of Best Practices

PURPOSE OF REVIEW

Summarize best practices for management of patients with early myelofibrosis (MF).

RECENT FINDINGS

Myelofibrosis is a progressive myeloproliferative neoplasm (MPN) that generally produces burdensome symptoms and ultimately leads to worse overall survival than that observed in healthy controls or patients with other MPNs. Several Janus kinase inhibitors and various interferon formulations are now available for treatment of MF, with ruxolitinib notable for extending overall survival in addition to improving MF signs and symptoms. The chronic nature of the disease can lead some patients to avoid immediate treatment in favor of a watch-and-wait approach. This review summarizes the patient management approach taken in my practice, providing guidance and a discussion of best practices with an emphasis on the importance and clinical benefits of active treatment in early MF. In particular, a case is made to consider treatment with ruxolitinib for patients with intermediate-1 risk disease and to minimize delay between diagnosis and treatment initiation for patients with intermediate or high-risk disease.

2024 update on allogeneic hematopoietic stem cell transplant for myelofibrosis: A review of current data and applications on risk stratification and management

BACKGROUND

Allogeneic hemopoietic stem cell transplantation (HSCT) currently remains the only curative treatment for patients with myelofibrosis (MF). Transplant related mortality (TRM) and relapse, remain two significant complications which need to be addressed.

AIMS

The aim of this manuscript is to review current available reports on changes which have recently occurred, to improve the outcome of MF patients undergoing an allogeneic HSCT.

METHODS

Published papers were used to analyze different aspects of allogeneic HSCT.

RESULTS

Changes and updates are provided on selection of patients, prognostic systems, managing splenomegaly, conditioning regimens, predicting transplant outcome, stem cell sources, stem cell donors, graft versus host disease (GvHD) prophylaxis, patients with blast phase, hematopoietic reconstitution, disease markers, donor chimerism, and treatment of relapse.

CONCLUSIONS

The review outlines new transplant platforms which are now available for patients with myelofibrosis, together with persisting problems, among which, older age combined with marrow fibrosis and an inflammatory disease. Relapse also requires aggressive monitoring of drivers mutations, and early cellular therapy.

Splenic irradiation for myelofibrosis prior to hematopoietic cell transplantation: A global collaborative analysis

Splenomegaly is the clinical hallmark of myelofibrosis. Splenomegaly at the time of allogeneic hematopoietic cell transplantation (HCT) is associated with graft failure and poor graft function. Strategies to reduce spleen size before HCT especially after failure to Janus kinase (JAK) inhibition represent unmet clinical needs in the field. Here, we leveraged a global collaboration to investigate the safety and efficacy of splenic irradiation as part of the HCT platform for patients with myelofibrosis. We included 59 patients, receiving irradiation within a median of 2 weeks (range, 0.9-12 weeks) before HCT. Overall, the median spleen size prior to irradiation was 23 cm (range, 14-35). Splenic irradiation resulted in a significant and rapid spleen size reduction in 97% of patients (57/59), with a median decrease of 5.0 cm (95% confidence interval, 4.1-6.3 cm). The most frequent adverse event was thrombocytopenia, with no correlation between irradiation dose and hematological toxicities. The 3-year overall survival was 62% (95% CI, 48%-76%) and 1-year non-relapse mortality was 26% (95% CI, 14%-38%). Independent predictors for survival were severe thrombocytopenia and anemia before irradiation, transplant-specific risk score, higher-intensity conditioning, and present portal vein thrombosis. When using a propensity score matching adjusted for common confounders, splenic irradiation was associated with significantly reduced relapse (p = .01), showing a 3-year incidence of 12% for splenic irradiation versus 29% for patients with immediate HCT and 38% for patients receiving splenectomy. In conclusion, splenic irradiation immediately before HCT is a reasonable approach in patients experiencing JAK inhibition failure and is associated with a low incidence of relapse.

Targeted Metabolomics Highlights Dramatic Antioxidant Depletion, Increased Oxidative/Nitrosative Stress and Altered Purine and Pyrimidine Concentrations in Serum of Primary Myelofibrosis Patients

To date, little is known concerning the circulating levels of biochemically relevant metabolites (antioxidants, oxidative/nitrosative stress biomarkers, purines, and pyrimidines) in patients with primary myelofibrosis (PMF), a rare form of myeloproliferative tumor causing a dramatic decrease in erythropoiesis and angiogenesis. In this study, using a targeted metabolomic approach, serum samples of 22 PMF patients and of 22 control healthy donors were analyzed to quantify the circulating concentrations of hypoxanthine, xanthine, uric acid (as representative purines), uracil, β-pseudouridine, uridine (as representative pyrimidines), reduced glutathione (GSH), ascorbic acid (as two of the main water-soluble antioxidants), malondialdehyde, nitrite, nitrate (as oxidative/nitrosative stress biomarkers) and creatinine, using well-established HPLC method for their determination. Results showed that PMF patients have dramatic depletions of both ascorbic acid and GSH (37.3- and 3.81-times lower circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001), accompanied by significant increases in malondialdehyde (MDA) and nitrite + nitrate (4.73- and 1.66-times higher circulating concentrations, respectively, than those recorded in healthy controls, p < 0.0001). Additionally, PMF patients have remarkable alterations of circulating purines, pyrimidines, and creatinine, suggesting potential mitochondrial dysfunctions causing energy metabolism imbalance and consequent increases in these cell energy-related compounds. Overall, these results, besides evidencing previously unknown serum metabolic alterations in PMF patients, suggest that the determination of serum levels of the aforementioned compounds may be useful to evaluate PMF patients on hospital admission for adjunctive therapies aimed at recovering their correct antioxidant status, as well as to monitor patients' status and potential pharmacological treatments.

Incidence of blast phase in myelofibrosis patients according to anemia severity at ruxolitinib start and during therapy

BACKGROUND

Anemia is frequently present in patients with myelofibrosis (MF), and it may be exacerbated by treatment with the JAK2-inhibitor ruxolitinib (RUX). Recently, a relevant blast phase (BP) incidence has been reported in anemic MF patients unexposed to RUX.

METHODS

The authors investigated the incidence of BP in 886 RUX-treated MF patients, included in the "RUX-MF" retrospective study.

RESULTS

The BP incidence rate ratio (IRR) was 3.74 per 100 patient-years (3.74 %p-y). At therapy start, Common Terminology Criteria for Adverse Events grade 3-4 anemia (hemoglobin [Hb] <8 g/dL) and severe sex/severity-adjusted anemia (Hb <8/<9 g/dL in women/men) were present in 22.5% and 25% patients, respectively. IRR of BP was 2.34 in patients with no baseline anemia and reached respectively 4.22, 4.89, and 4.93 %p-y in patients with grade 1, 2, and 3-4 anemia. Considering the sex/severity-adjusted Hb thresholds, IRR of BP was 2.85, 4.97, and 4.89 %p-y in patients with mild/no anemia, moderate, and severe anemia. Transfusion-dependent patients had the highest IRR (5.03 %p-y). Progression-free survival at 5 years was 70%, 52%, 43%, and 27% in patients with no, grade 1, 2, and 3-4 anemia, respectively (p < .001). At 6 months, 260 of 289 patients with no baseline anemia were receiving ruxolitinib, and 9.2% had developed a grade 3-4 anemia. By 6-month landmark analysis, BP-free survival was significantly worse in patients acquiring grade 3-4 anemia (69.3% vs. 88.1% at 5 years, p < .001).

CONCLUSIONS

This study highlights that anemia correlates with an increased risk of evolution into BP, both when present at baseline and when acquired during RUX monotherapy. Innovative anemia therapies and disease-modifying agents are warranted in these patients.

Advances in pharmacotherapy for myelofibrosis: what is the current state of play?

INTRODUCTION

The introduction of the first JAK inhibitor (JAKi) ruxolitinib 10 years ago represented a pivotal advancement in myelofibrosis (MF) treatment, mostly in terms of spleen and symptoms response. Nowadays three more JAKi, fedratinib, pacritinib, and momelotinib, are available for both ruxolitinib-resistant and naïve patients. Moreover, many drugs are currently being investigated, both alone and in combination with JAKi.

AREAS COVERED

In this review we discuss the long-term data of ruxolitinib and more recent evidence coming from clinical trials of fedratinib, pacritinib, and momelotinib, used as first- or second-line MF therapy. More, focus is set on data from non-JAKi drugs, such as the quite extensively studied BET-inhibitors (pelabresib) and BCL-inhibitors (navitoclax), novel target therapies, and drugs aimed to improve anemia, still representing a major determinant of reduced survival in MF.

EXPERT OPINION

It's now evident that JAKi monotherapy, though clinically effective, is rarely able to change MF natural history; novel drugs are promising but long-term data are inevitably lacking. We feel that soon MF treatment will require clinicians to select the most appropriate JAKi inhibitor, based on patient characteristics, associating either front-line or in case of early suboptimal response, non-JAKi drugs with the aim to pursue disease modification.

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.

Investigation of Serum Albumin as a Dynamic Treatment-Specific Surrogate for Outcomes in Patients With Myelofibrosis Treated With Ruxolitinib

PURPOSE

Ruxolitinib improves splenomegaly and disease-related symptoms in most patients with myelofibrosis (MF), and it has been associated with a survival benefit in higher-risk patients with splenomegaly. Spleen volume reduction has been associated with a survival benefit in ruxolitinib-treated patients; however, its use as a surrogate is limited. We hypothesized that an anti-inflammatory response to ruxolitinib would correlate with improved patient outcomes.

METHODS

We interrogated serum albumin, an acute phase reactant and marker of nutritional status in 590 patients with MF and analyzed differential trajectories of albumin on the basis of ruxolitinib treatment. Additionally, we assessed the prognostic role of baseline albumin and change in albumin.

RESULTS

We found that serum albumin levels tend to decrease in patients with MF; however, this tendency is abrogated by ruxolitinib treatment. To that end, baseline serum albumin level correlates with overall survival (OS) in patients with MF, independent of the variables that comprise the dynamic international prognostic scoring system; however, this correlation is limited to ruxolitinib-naïve patients. In ruxolitinib-treated patients, the change in serum albumin after ruxolitinib treatment, rather than the baseline value, is associated with improved OS, a finding not seen in ruxolitinib-naïve patients.

CONCLUSION

These findings suggest that serum albumin, a ubiquitously available laboratory value, has specific relevance in patients with MF and reflects therapeutic response to ruxolitinib.

Neutrophil to lymphocyte ratio in myelofibrosis patients treated with ruxolitinib may predict prognosis and rate of discontinuation

BACKGROUND

Myelofibrosis (MF) is a clonal Philadelphia chromosome negative myeloproliferative neoplasm (Ph-MPN). MF is featured by an inflammatory condition that can also drive the progression of disease. Ruxolitinib (ruxo) is the-first-in-class Jak1/2 inhibitor approved for treatment of MF, proved to reduce spleen volume and decrease symptom burden. In various malignancies neutrophil-to-lymphocyte ratio (NLR) has been indicated as predictor of progression free survival (PFS) and overall survival (OS). NLR might reflect the balance between systemic inflammation and immunity and is emerging as a prognostic biomarker in several neoplasms, including the hematological ones.

METHODS

We analyzed a cohort of 140 MF patients treated with ruxo to validate baseline NLR (as a continuous variable and as a cut-off 2) as predictor of OS and of ruxo treatment discontinuation.

RESULTS

We found that both baseline NLR as a continuous variable [HR 0.8 (95% CI: 0.7-0.9) (p = .006)] and NLR (<2 vs. ≥2) [HR 3.4 (95% CI: 1.6-7.0) (p = .001)] were significantly associated with OS. Censoring for patients undergone allotransplant, baseline NLR <2 was predictive of an earlier ruxo any-other-cause discontinuation [HR 3.7 (95%CI 1.7-8.3) (p < .001)].

CONCLUSIONS

NLR before starting ruxo treatment may be used as a simple and early predictor of OS and earlier ruxo discontinuation in clinical practice.

Indication and management of allogeneic haematopoietic stem-cell transplantation in myelofibrosis: updated recommendations by the EBMT/ELN International Working Group

New options for medical therapy and risk scoring systems containing molecular data are leading to increased complexity in the management of patients with myelofibrosis. To inform patients' optimal care, we updated the 2015 guidelines on indications for and management of allogeneic haematopoietic stem-cell transplantation (HSCT) with the support of the European Society for Blood and Marrow Transplantation (EBMT) and European LeukemiaNet (ELN). New recommendations were produced using a consensus-building methodology after a comprehensive review of articles released from January, 2015 to December, 2022. Seven domains and 18 key questions were selected through a series of questionnaires using a Delphi process. Key recommendations in this update include: patients with primary myelofibrosis and an intermediate-2 or high-risk Dynamic International Prognostic Scoring System score, or a high-risk Mutation-Enhanced International Prognostic Score Systems (MIPSS70 or MIPSS70-plus) score, or a low-risk or intermediate-risk Myelofibrosis Transplant Scoring System score should be considered candidates for allogeneic HSCT. All patients who are candidates for allogeneic HSCT with splenomegaly greater than 5 cm below the left costal margin or splenomegaly-related symptoms should receive a spleen-directed treatment, ideally with a JAK-inhibitor; HLA-matched sibling donors remain the preferred donor source to date. Reduced intensity conditioning and myeloablative conditioning are both valid options for patients with myelofibrosis. Regular post-transplantation driver mutation monitoring is recommended to detect and treat early relapse with donor lymphocyte infusion. In a disease where evidence-based guidance is scarce, these recommendations might help clinicians and patients in shared decision making.

ACVR1: A Novel Therapeutic Target to Treat Anemia in Myelofibrosis

Activin receptor type I (ACVR1) is a transmembrane kinase receptor belonging to bone morphogenic protein receptors (BMPs). ACVR1 plays an important role in hematopoiesis and anemia via the BMP6/ACVR1/SMAD pathway, which regulates expression of hepcidin, the master regulator of iron homeostasis. Elevated hepcidin levels are inversely associated with plasma iron levels, and chronic hepcidin expression leads to iron-restricted anemia. Anemia is one of the hallmarks of myelofibrosis (MF), a bone marrow (BM) malignancy characterized by BM scarring resulting in impaired hematopoiesis, splenomegaly, and systemic symptoms. Anemia and red blood cell transfusions negatively impact MF prognosis. Among the approved JAK inhibitors (ruxolitinib, fedratinib, momelotinib, and pacritinib) for MF, momelotinib and pacritinib are preferably used in cytopenic patients; both agents are potent ACVR1 inhibitors that suppress hepcidin expression via the BMP6/ACVR1/SMAD pathway and restore iron homeostasis/erythropoiesis. In September 2023, momelotinib was approved as a treatment for patients with MF and anemia. Zilurgisertib (ACVR1 inhibitor) and DISC-0974 (anti-hemojuvelin monoclonal antibody) are evaluated in early phase clinical trials in patients with MF and anemia. Luspatercept (ACVR2B ligand trap) is assessed in transfusion-dependent MF patients in a registrational phase 3 trial. Approved ACVR1 inhibitors and novel agents in development are poised to improve the outcomes of anemic MF patients.

Polycythemia Vera: Barriers to and Strategies for Optimal Management

Polycythemia vera (PV) is a subtype of myeloproliferative neoplasms characterized by impaired quality of life and severe complications. Despite the increasingly in-depth knowledge of this condition, it necessitates a multifaceted management approach to mitigate symptoms and prevent thrombotic and hemorrhagic events, ensuring prolonged survival. The therapeutic landscape has been revolutionized in recent years, where venesection and hydroxycarbamide associated with antiplatelet therapy have a central role and are now accompanied by other drugs, such as interferon and Janus kinase inhibitors. Ongoing research and advancements in targeted therapies hold promise for further enhancing the therapeutic choice for PV management.

Evolving landscape of JAK inhibition in myelofibrosis: monotherapy and combinations

Myeloproliferative neoplasms (MPNs) are characterized by clonal myeloproliferation in 1 or more of the hematopoietic stem cell lineages. Primary myelofibrosis (MF), post-polycythemia vera MF, and post-essential thrombocythemia MF have the worst prognosis and are characterized by the presence of cytokine-mediated symptom complex, splenomegaly, progressive marrow failure, and clonal instability, leading to leukemic transformation. The key therapeutic aims encompass the management of symptoms, splenomegaly, and anemia and the improvement of survivals. These therapeutic aims have evolved with the availability of Jak inhibitors and novel agents, making disease modification potentially achievable. Novel agents may potentially target MPN stem cells, epigenetic alterations, signaling pathways, and apoptotic pathways. In this case-based review, we outline our approach to the management of MF and discuss the therapeutic landscape of MF, highlighting the utility of Jak inhibitors and novel Jak inhibitor-based combinations.

Real-world outcomes with fedratinib therapy in patients who discontinued ruxolitinib for primary myelofibrosis

Aim: Fedratinib is an oral selective JAK2 inhibitor approved in the USA for the treatment of adult patients with intermediate-2 or high-risk primary or secondary myelofibrosis (MF). Methods: This observational study assessed adult US patients who received ruxolitinib for primary MF (Flatiron Health database: 1 January 2011-31 October 2020). Patients were stratified by post-ruxolitinib treatment (fedratinib vs non-fedratinib). Results: Characteristics were comparable between fedratinib (n=70) and non-fedratinib (n=159) groups (median age: 71.0 vs 70.0 years; females: 55.7 vs 50.3%; median follow-up: 7.0 vs 6.0 months). Median overall survival (not reached vs 17 months) and 12 month survival (71.6 vs 53.5%) were improved with fedratinib versus the non-fedratinib therapies. Conclusion: In MF patients who received frontline ruxolitinib, survival was improved with subsequent fedratinib versus non-fedratinib care.

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.

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.

AIPSS-MF machine learning prognostic score validation in a cohort of myelofibrosis patients treated with ruxolitinib

BACKGROUND

In myelofibrosis (MF), new model scores are continuously proposed to improve the ability to better identify patients with the worst outcomes. In this context, the Artificial Intelligence Prognostic Scoring System for Myelofibrosis (AIPSS-MF), and the Response to Ruxolitinib after 6 months (RR6) during the ruxolitinib (RUX) treatment, could play a pivotal role in stratifying these patients.

AIMS

We aimed to validate AIPSS-MF in patients with MF who started RUX treatment, compared to the standard prognostic scores at the diagnosis and the RR6 scores after 6 months of treatment.

METHODS AND RESULTS

At diagnosis, the AIPSS-MF performs better than the widely used IPSS for primary myelofibrosis (C-index 0.636 vs. 0.596) and MYSEC-PM for secondary (C-index 0.616 vs. 0.593). During RUX treatment, we confirmed the leading role of RR6 in predicting an inadequate response by these patients to JAKi therapy compared to AIPSS-MF (0.682 vs. 0.571).

CONCLUSION

The new AIPSS-MF prognostic score confirms that it can adequately stratify this subgroup of patients already at diagnosis better than standard models, laying the foundations for new prognostic models developed tailored to the patient based on artificial intelligence.

A Journey Through JAK Inhibitors for the Treatment of Myeloproliferative Diseases

PURPOSE OF REVIEW

Chronic myeloproliferative neoplasms (MPN) represent a group of diseases characterised by constitutive activation of the JAK/STAT pathway in a clonal myeloid precursor. The therapeutic approach aims to treat the symptom burden (headache, itching, debilitation), splenomegaly, slow down the fibrotic proliferation in the bone marrow and reduce the risk of thrombosis/bleeding whilst avoiding leukaemic transformation.

RECENT FINDINGS

In recent years, the advent of JAK inhibitors (JAKi) has significantly broadened treatment options for these patients. In myelofibrosis, symptom control and splenomegaly reduction can improve quality of life with improved overall survival, not impacting progression into acute leukaemia. Several JAKi are available and used worldwide, and combination approaches are now being explored. In this chapter, we review the approved JAKi, highlighting its strengths, exploring potential guidelines in choosing which one to use and reasoning towards future perspectives, where the combinations of therapies seem to promise the best results.

Relevant Clinical Factors in Patients with Myelofibrosis on Ruxolitinib for 5 or More Years

INTRODUCTION

Median duration of therapy with the first JAK1/2 inhibitor ruxolitinib (RUX) approved for patients with intermediate or high-risk myelofibrosis (MF) is about 3 years.

METHODS

In this retrospective study, we aimed to evaluate clinical features, predictive factors, and outcome of patients presenting to our institution who were able to remain on RUX for ≥5 years (RUX ≥5y, n = 73).

RESULTS

Comparing baseline demographics of patients who remained on RUX ≥5y (n = 73) with patients who were on RUX for 6 months to 3 years (n = 203), we confirmed that patients on RUX ≥5y lacked advanced clinical features at the start of therapy, such as anemia, neutropenia, thrombocytopenia, higher blasts or monocytes. Predictive independent factors for staying on RUX ≥5y were hemoglobin >10 g/dL, circulating blasts <1%, platelets >150 × 109/L, neutrophils >70%, and having primary MF. Age over 65 years remained significant for outcome in patients on RUX ≥5y.

CONCLUSION

In this retrospective study, we report on the relevance of absence of advanced clinical features for long RUX therapy and confirm the role of age on outcome despite therapy.

The pharmacotherapeutic management of patients with myelofibrosis: looking beyond JAK inhibitors

INTRODUCTION

The approach to myelofibrosis (MF) has been revolutionized in recent years, overcoming the traditional therapies, often not very effective. Janus kinase inhibitors (JAKi - from ruxolitinib up to momelotinib) were the first class of drugs with considerable results.

AREAS COVERED

Ongoing, new molecules are being tested that promise to give hope even to those patients not eligible for bone marrow transplants who become intolerant or are refractory to JAKi, for which therapeutic hopes are currently limited. Telomerase, murine double minute 2 (MDM2), phosphatidylinositol 3-kinase δ (PI3Kδ), BCL-2/xL, and bromodomain and extra-terminal motif (BET) inhibitors are the drugs with promising results in clinical trials and close to closure with consequent placing on the market, finally allowing JAK to look beyond. The novelty of the MF field was searched in the PubMed database, and the recently completed/ongoing trials are extrapolated from the ClinicalTrial website.

EXPERT OPINION

From this point of view, the use of new molecules widely described in this review, probably in association with JAKi, will represent the future treatment of choice in MF, leaving, in any case, the potential new approaches actually in an early stage of development, such as the use of immunotherapy in targeting CALR, which is coming soon.

Recent progress of JAK inhibitors for hematological disorders

JAK inhibitors are important therapeutic options for hematological disorders, especially myeloproliferative neoplasms. Ruxolitinib, the first JAK inhibitor approved for clinical use, improves splenomegaly and ameliorates constitutional symptoms in both myelofibrosis and polycythemia vera patients. Ruxolitinib is also useful for controlling hematocrit levels in polycythemia vera patients who were inadequately controlled by conventional therapies. Furthermore, pretransplantation use of ruxolitinib may improve the outcome of allo-hematopoietic stem cell transplantation in myelofibrosis. In contrast to these clinical merits, evidence of the disease-modifying action of ruxolitinib, i.e., reduction of malignant clones or improvement of bone marrow pathological findings, is limited, and many myelofibrosis patients discontinued ruxolitinib due to adverse events or disease progression. To overcome these limitations of ruxolitinib, several new types of JAK inhibitors have been developed. Among them, fedratinib was proven to provide clinical merits even in patients who were resistant or intolerant to ruxolitinib. Pacritinib and momelotinib have shown merits for myelofibrosis patients with thrombocytopenia or anemia, respectively. In addition to treatment for myeloproliferative neoplasms, recent studies have demonstrated that JAK inhibitors are novel and attractive therapeutic options for corticosteroid-refractory acute as well as chronic graft versus host disease.

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.

Ten years of treatment with ruxolitinib for myelofibrosis: a review of safety

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm characterized by bone marrow fibrosis, anemia, extramedullary hematopoiesis, and splenomegaly. Patients with MF are at risk for reduced survival versus the general population and often experience burdensome signs and symptoms that reduce quality of life. The oral Janus kinase (JAK) 1/JAK2 inhibitor ruxolitinib was initially approved by the US Food and Drug Administration in 2011 for the treatment of patients with intermediate or high-risk MF, including primary MF, post-polycythemia vera MF, and post-essential thrombocythemia MF, based on efficacy and safety findings from the randomized, controlled, phase 3 COMFORT trials. Over a decade later, ruxolitinib continues to be the standard of care in higher-risk MF, and dose optimization and management remain crucial for safely maximizing clinical benefits of ruxolitinib. This review summarizes the safety profile of ruxolitinib in patients with MF in the COMFORT trials leading up to approval and in the subsequent JUMP, ROBUST, EXPAND, and REALISE trials; in pooled analyses; and in postmarketing analyses in the 10 years following approval. There is a focus on the occurrence of common hematologic and nonhematologic adverse events, with guidance provided on the management of patients with anemia or thrombocytopenia, including dosing strategies based on findings from the REALISE and EXPAND trials. Finally, to ensure a greater understanding of the safety profile of ruxolitinib, practical considerations are discussed.

Association of Myelofibrosis Phenotypes with Clinical Manifestations, Molecular Profiles, and Treatments

Myelofibrosis (MF) presents an array of clinical manifestations and molecular profiles. The two distinct phenotypes- myeloproliferative and myelodepletive or cytopenic- are situated at the two poles of the disease spectrum and are largely defined by different degrees of cytopenias, splenomegaly, and distinct molecular profiles. The myeloproliferative phenotype is characterized by normal/higher peripheral blood counts or mildly decreased hemoglobin, progressive splenomegaly, and constitutional symptoms. The myeloproliferative phenotype is typically associated with secondary MF, higher JAK2 V617F burden, fewer mutations, and superior overall survival (OS). The myelodepletive phenotype is usually associated with primary MF, ≥2 cytopenias, modest splenomegaly, lower JAK2 V617F burden, higher fibrosis, greater genomic complexity, and inferior OS. Cytopenias are associated with mutations in epigenetic regulators/splicing factors, clonal evolution, disease progression, and shorter OS. Clinical variables, in conjunction with the molecular profiles, inform integrated prognostication and disease management. Ruxolitinib/fedratinib and pacritinib/momelotinib may be more suitable to treat patients with the myeloproliferative and myelodepletive phenotypes, respectively. Appreciation of MF heterogeneity and two distinct phenotypes, the different clinical manifestations and molecular profiles associated with each phenotype alongside the growing treatment expertise, the development of non-myelosuppressive JAK inhibitors, and integrated prognostication are leading to a new era in patient management. Physicians can increasingly tailor personalized treatments that will address the unique unmet needs of MF patients, including those presenting with the myelodepletive phenotype, to elicit optimal outcomes and extended OS across the disease spectrum.

Moving Beyond Ruxolitinib Failure in Myelofibrosis: Evolving Strategies for Second Line Therapy

Ruxolitinib has been the cornerstone of pharmacologic therapy for myelofibrosis for over a decade. However, the last several years have witnessed the regulatory approval of other Janus kinase (JAK) inhibitors for myelofibrosis, i.e. fedratinib, pacritinib, and US approval of momelotinib is widely anticipated in 2023. Due to the multifaceted clinical presentation of myelofibrosis, a watertight definition of ruxolitinib failure has remained elusive, as "progression" on ruxolitinib can take many forms and management is highly nuanced. Yet, the availability of other JAK inhibitors and potential future availability of non-JAK inhibitor agents for myelofibrosis make a consensus on management of ruxolitinib failure critically important. This consensus paper summarizes a discussion between multiple academic and community physician experts, a pharmacist and an advanced practice provider around the issues to be considered for the optimal care of patients with myelofibrosis whose disease is refractory to or does not respond adequately to ruxolitinib, or who exhibit intolerance to ruxolitinib. The panel identified several areas of consensus, as well as some areas where more data to inform evidence-based practice are needed. In some situations, maintaining ruxolitinib while adding another agent, e.g. to address anemia, is appropriate, whereas in others, switching to a different drug has merit.

Ten years after ruxolitinib approval for myelofibrosis: a review of clinical efficacy

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm characterized by splenomegaly, abnormal cytokine expression, cytopenias, and progressive bone marrow fibrosis. The disease often manifests with burdensome symptoms and is associated with reduced survival. Ruxolitinib, an oral Janus kinase (JAK) 1 and JAK2 inhibitor, was the first agent approved for MF. As a first-in-class targeted treatment, ruxolitinib approval transformed the MF treatment approach and remains standard of care. In addition, targeted inhibition of JAK1/JAK2 signaling, a key molecular pathway underlying MF pathogenesis, and the large volume of literature evaluating ruxolitinib, have led to a better understanding of the disease and improved management in general. Here we review ruxolitinib efficacy in patients with MF in the 10 years following approval, including demonstration of clinical benefit in the phase 3 COMFORT-I/II trials, real-world evidence, translational studies, and expanded access data. Lastly, future directions for MF treatment are discussed, including ruxolitinib-based combination therapies.

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.

Myelofibrosis and Survival Prognostic Models: A Journey between Past and Future

Among the myeloproliferative diseases, myelofibrosis is a widely heterogeneous entity characterized by a highly variable prognosis. In this context, several prognostic models have been proposed to categorize these patients appropriately. Identifying who deserves more invasive treatments, such as bone marrow transplantation, is a critical clinical need. Age, complete blood count (above all, hemoglobin value), constitutional symptoms, driver mutations, and blast cells have always represented the milestones of the leading models still used worldwide (IPSS, DIPSS, MYSEC-PM). Recently, the advent of new diagnostic techniques (among all, next-generation sequencing) and the extensive use of JAK inhibitor drugs have allowed the development and validation of new models (MIPSS-70 and version 2.0, GIPSS, RR6), which are continuously updated. Finally, the new frontier of artificial intelligence promises to build models capable of drawing an overall survival perspective for each patient. This review aims to collect and summarize the existing standard prognostic models in myelofibrosis and examine the setting where each of these finds its best application.

Leishmania Infection during Ruxolitinib Treatment: The Cytokines-Based Immune Response in the Setting of Immunocompromised Patients

Ruxolitinib is a JAK1/2 inhibitor that has revolutionized the approach to myelofibrosis. On the one side, this drug can rapidly improve the symptoms related to the hematological disease; on the other side, the inhibition of JAK1/2 can lead to immunosuppression which may increase the risk of infections, due to a change in the cytokine balance in favor of anti-inflammatory cytokines, to direct inhibition of immune cells, and to the suppression in the production of specific antibodies. In this patient setting, much is known about possible viral and bacterial infections, while little is reported in the literature concerning parasitic infections, specifically leishmaniasis. Leishmania is a parasitic infection that can cause serious problems in immunosuppressed patients. The parasite can invade the bloodstream and cause a wide range of symptoms, including fever, weight loss, and anemia. In severe cases, it can lead to multi-organ failure and, rapidly, death. Early diagnosis and prompt treatment are essential especially for these patients, unable to respond adequately. In this case and the following review of the existing literature, the cytokine kinetics and the production of specific anti-Leishmania antibodies represent characteristic aspects capable of providing a more in-depth understanding of the mechanisms underlying these complex clinical cases in an immunocompromised patient.