Therapeutic approaches in myelofibrosis

SOHO State of the Art Updates and Next Questions | Updates on Myelofibrosis With Cytopenia

Myelofibrosis (MF) is a rare hematologic malignancy that is characterized by dysregulation of the JAK-STAT pathway resulting in fibrosis of the bone marrow, splenomegaly, and abnormalities in peripheral blood counts including anemia, leukocytosis, and thrombocytopenia. This disease has 2 phenotypic extremes - myeloproliferative and cytopenic. Cytopenic myelofibrosis presents with pronounced cytopenia and a different landscape of genetic mutations which results in worse clinical outcomes and a poor prognosis. Patients with cytopenic MF are at high risk of developing various complications like bleeding, infections, and transfusion dependency. Historically, the only Federal Drug Administration (FDA) approved therapy was ruxolitinib, a JAK1/2 inhibitor, which improved constitutional symptoms and splenomegaly, however, exacerbated anemia and thrombocytopenia.1,2 There were very few options for patients with anemia and thrombocytopenia, and supportive treatments for these problems lack efficacy. Fortunately, there are newer treatment options which may allow for treatment of the symptoms and splenomegaly in the setting of cytopenias and even improve cytopenias. This up-to-date review not only highlights the prevalent options in therapeutic marketplace, but also sheds light on the significant unmet need of addressing anemia and thrombocytopenia in cytopenic MF.

Therapeutic Results and Survival of Patients with Myelofibrosis Treated with Ruxolitinib-A Real-Life Longitudinal Study

The aim of this study was to analyze the therapeutic results and survival of patients with myelofibrosis treated with ruxolitinib in comparison with a group on standard therapy. It is a cross-sectional, retrospective, non-interventional, real-life study that was performed between January 2000 and February 2023. Patients treated between 2000 and 2016, before the introduction of ruxolitinib, constituted the control group (n = 45), while those treated after May 2016, after ruxolitinib inclusion, constituted the active group (n = 66). Demographic characteristics, clinical indicators, the severity of the disease, and survival were explored using Kaplan-Meier survival analyses. Spearman's correlation, linear regression, and other statistical analyses were performed. According to the Kaplan-Meier analysis, there was a 75.33% reduction in the fatality risk in the sample. On a general-population level, the fatality risk in the group treated with ruxolitinib varied between 7.9% and 77.18% compared to that of the risk in the control group. There was a decrease in blood parameters (leukocytes, hemoglobin, and platelets) and spleen size. During the first six months, the spleen size of the patients on ruxolitinib decreased by 6%, and during the second six months, it decreased by another 9%. This study shows that patients in a real-life clinical setting treated with ruxolitinib exhibited improved clinical signs of the disease, had a lower symptom severity, and survived longer than patients on standard therapy before ruxolitinib's entrance into the national market. The improvements correlate with those reported in randomized clinical trials.

A decade of approved first-in-class small molecule orphan drugs: Achievements, challenges and perspectives

In the past decade (2011-2020), there was a growing interest in the discovery and development of orphan drugs for the treatment of rare diseases. However, rare diseases only account for a population of 0.65‰-1‰ which usually occur with previously unknown biological mechanisms and lack of specific therapeutics, thus to increase the demands for the first-in-class (FIC) drugs with new biological targets or mechanisms. Considering the achievements in the past 10 years, a total of 410 drugs were approved by U.S. Food and Drug Administration (FDA), which contained 151 FIC drugs and 184 orphan drugs, contributing to make up significant numbers of the approvals. Notably, more than 50% of FIC drugs are developed as orphan drugs and some of them have already been milestones in drug development. In this review, we aim to discuss the FIC small molecules for the development of orphan drugs case by case and highlight the R&D strategy with novel targets and scientific breakthroughs.

Radiation for Palliation: Role of Palliative Radiotherapy in Allevieating Pain/Symptoms in a Prospective Observational Study at Two Tertiary Care Centers

Purpose

Approximately one-third of patients attending the tertiary care center require palliative management. The purpose of this study was to investigate the role of palliative radiation in alleviating the pain and symptoms and improvement in quality of life (QOL).

Methods

This was a prospective study aimed to evaluate patients attending two oncology centers and those who require palliative radiation. During 3 years, 1365 patients attended radiation oncology center for various malignancies. Of these patients, 304 patients were treated with palliative radiation for various indications. These patients were followed up for a period of up to 6 months for symptom relief and improved QOL.

Results

About 22% of patients received palliative radiation primarily for carcinoma lung, breast, and prostate malignancy. Analysis revealed elderly patients in the age group of 50-70 being the most commonly affected and most common presentation was pain, swelling, and headache. The most common site of metastases was bone including the spine and brain. Most commonly employed schedule of palliative radiation was 30 Gy in 10 fractions and 20 Gy in 5 fractions. Patients responded well to palliative radiation and had improved pain relief and QOL.

Conclusions

Palliative radiation is an important part of the management of cancer care and when given improves QOL, and significant pain relief.

Treatment With JAK Inhibitors in Myelofibrosis Patients Nullifies the Prognostic Impact of Unfavorable Cytogenetics

INTRODUCTION

In the era before Janus kinase (JAK) inhibitors, cytogenetic information was used to predict survival in myelofibrosis patients. However, the prognostic value of cytogenetics in the setting of JAK inhibitor therapy remains unknown.

PATIENTS AND METHODS

We performed a retrospective analysis of 180 patients with bone marrow biopsy-proven myelofibrosis from 3 US academic medical centers. We fit Cox proportional hazards models for overall survival and transformation-free survival on the bases of 3 factors: JAK inhibitor therapy as a time-dependent covariate, dichotomized cytogenetic status (favorable vs. unfavorable), and statistical interaction between the two. The median follow-up time was 37.1 months.

RESULTS

Among patients treated with best available therapy, unfavorable cytogenetic status was associated with decreased survival (hazard ratio = 2.31; P = .025). At initiation of JAK inhibitor therapy, unfavorable cytogenetics was (nonsignificantly) associated with increased survival compared to favorable cytogenetics (hazard ratio = 0.292; P = .172). The ratio of hazard ratios was 0.126 (P = .034). These findings were similar after adjusting for standard clinical prognostic factors as well as when measured against transformation-free survival.

CONCLUSION

The initiation of JAK inhibitor therapy appears to change the association between cytogenetics and overall survival. There was little difference in survival between treatment types in patients with favorable cytogenetics. However, the use of JAK inhibitor therapy among patients with unfavorable cytogenetics was not associated with worse survival compared to favorable cytogenetics. Our analyses suggest that initiation of JAK inhibitor therapy nullifies the negative prognostic implication of unfavorable cytogenetics established in the pre-JAK inhibitor therapy era.

[Efficacy and safety of JAK inhibitor ruxolitinib in Chinese patients with myelofibrosis: results of a 1-year follow-up of A2202]

目的

评价芦可替尼在中国骨髓纤维化患者中的疗效和安全性。

方法

63例中国骨髓纤维化患者纳入研究，男32例，女31例，中位年龄55(25~79)岁。芦可替尼起始剂量：基线PLT(100~200)×10⁹/L者(25例)30 mg/d，基线PLT>200×10⁹/L者(38例)40 mg/d。使用MRI/CT、欧洲癌症研究与治疗组织生活质量调查问卷核心30(EORTC QLQ-C30)和骨髓纤维化症状评估表(MFSAF)v2.0对患者进行脾脏体积、生活质量和症状评估。

结果

截至12个月随访结束，47例(74.6%)患者仍在继续治疗，25例(39.7%)患者脾脏体积较基线缩小超过35%，首次达到脾脏体积缩小≥35％的中位时间为12.71(95%CI 12.14~35.00)周。治疗期间，85.7%(54/63)的患者有不同程度的脾脏缩小，中位最佳脾脏体积缩小百分比为35.5%，48周时中位脾脏缩小体积为34.7%。治疗48周时53.1 %(26/49)的患者MFSAF症状评分降低超过50%，生活质量得到改善。最常见的血液学不良事件包括贫血和血小板计数降低，但极少造成停药。非血液学不良事件以1/2级为主。

结论

芦可替尼使中国骨髓纤维化患者的脾脏体积获得持续缩小、症状改善，不良反应可耐受。

Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis

BACKGROUND

Myelofibrosis is a bone marrow disorder characterized by excessive production of reticulin and collagen fiber deposition caused by hematological and non-hematological disorders. The prognosis of myelofibrosis is poor and treatment is mainly palliative. Janus kinase inhibitors are a novel strategy to treat people with myelofibrosis.

OBJECTIVES

To determine the clinical benefits and harms of Janus kinase-1 and Janus kinase-2 inhibitors for treating myelofibrosis secondary to hematological or non-hematological conditions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library 2014, Issue 11), Ovid MEDLINE (from 1946 to 13 November 2014), EMBASE (from 1980 to 12 January 2013), and LILACS (from 1982 to 20 November 2014). We searched WHO International Clinical Trials Registry Platform and The metaRegister of Controlled Trials. We also searched for conference proceedings of the American Society of Hematology (from 2009 to October 2013), European Hematology Association (from 2009 to October 2013), American Society of Clinical Oncology (from 2009 to October 2013), and European Society of Medical Oncology (from 2009 to October 2013). We included searches in FDA, European Medicines Agency, and Epistemonikos. We handsearched the references of all identified included trials, and relevant review articles. We did not apply any language restrictions. Two review authors independently screened search results.

SELECTION CRITERIA

We included randomized clinical trials comparing Janus kinase-1 and Janus kinase-2 inhibitors with placebo or other treatments. Both previously treated and treatment naive patients were included.

DATA COLLECTION AND ANALYSIS

We used the hazard ratio (HR) and 95% confidence interval (95% CI) for overall survival, progression-free survival and leukemia-free survival, risk ratio (RR) and 95% CI for reduction in spleen size and adverse events binary data, and standardized mean differences (SMD) and 95% CI for continuous data (health-related quality of life). Two review authors independently extracted data and assessed the risk of bias of included trials. Primary outcomes were overall survival, progression-free survival and adverse events.

MAIN RESULTS

We included two trials involving 528 participants, comparing ruxolitinib with placebo or best available therapy (BAT). As the two included trials had different comparators we did not pool the data. The confidence in the results estimates of these trials was low due to the bias in their design, and their limited sample sizes that resulted in imprecise results.There is low quality evidence for the effect of ruxolitinib on survival when compared with placebo at 51 weeks of follow-up (HR 0.51, 95% CI 0.27 to 0.98) and compared with BAT at 48 weeks of follow-up (HR 0.70, 95% CI 0.20 to 2.47). Similarly there was very low quality evidence for the effect of ruxolitinib on progression free survival compared with BAT (HR 0.81, 95% CI 0.47 to 1.39).There is low quality evidence for the effect of ruxolitinib in terms of quality of life. Compared with placebo, the drug achieved a greater proportion of patients with a significant reduction of symptom scores (RR 8.82, 95% CI 4.40 to 17.69), and treated patients with ruxolitinib obtained greater MFSAF scores at the end of follow-up (MD -87.90, 95% CI -139.58 to -36.22). An additional trial showed significant differences in EORTC QLQ-C30 scores when compared ruxolitinib with best available therapy (MD 7.60, 95% CI 0.35 to 14.85).The effect of ruxolitinib on reduction in the spleen size of participants compared with placebo or BAT was uncertain (versus placebo: RR 64.58, 95% CI 9.08 to 459.56, low quality evidence; versus BAT: RR 41.78, 95% CI 2.61 to 669.75, low quality evidence).There is low quality evidence for the effect of the drug compared with placebo on anemia (RR 2.35, 95% CI 1.62 to 3.41), neutropenia (RR 3.57, 95% CI 1.02 to 12.55) and thrombocytopenia (RR 9.74, 95% CI 2.32 to 40.96). Ruxolitinib did not result in differences versus BAT in the risk of anemia (RR 1.35, 95% CI 0.91 to 1.99, low quality evidence) or thrombocytopenia (RR 1.20; 95% CI 0.44 to 3.28, low quality evidence). The risk of non-hematologic grade 3 or 4 adverse events (including fatigue, arthralgia, nausea, diarrhea, extremity pain and pyrexia) was similar when ruxolitinib was compared with placebo or BAT. The rate of neutropenia comparing ruxolitinib with standard medical treatment was not reported by the trial.

AUTHORS' CONCLUSIONS

Currently, there is insufficient evidence to allow any conclusions regarding the efficacy and safety of ruxolitinib for treating myelofibrosis. The findings of this Cochrane review should be interpreted with caution as they are based on trials sponsored by industry, and include a small number of patients. Unless powered randomized clinical trials provide strong evidence of a treatment effect, and the trade-off between potential benefits and harms is established, clinicians should be cautious when administering ruxolitinib for treating patients with myelofibrosis.

Myeloproliferative neoplasms working group consensus recommendations for diagnosis and management of primary myelofibrosis, polycythemia vera, and essential thrombocythemia

According to the 2008 revision of the World Health Organization (WHO) classification of myeloid malignancies, philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs) include clonal, hematologic disorders such as polycythemia vera, primary myelofibrosis, and essential thrombocythemia.

Recent years have witnessed major advances in the understanding of the molecular pathophysiology of these rare subgroups of chronic, myeloproliferative disorders. Identification of somatic mutations in genes associated with pathogenesis and evolution of these myeloproliferative conditions (Janus Kinase 2; myeloproliferative leukemia virus gene; calreticulin) led to substantial changes in the international guidelines for diagnosis and treatment of Ph-negative MPN during the last few years.

The MPN-Working Group (MPN-WG), a panel of hematologists with expertise in MPN diagnosis and treatment from various parts of India, examined applicability of this latest clinical and scientific evidence in the context of hematology practice in India.

This manuscript summarizes the consensus recommendations formulated by the MPN-WG that can be followed as a guideline for management of patients with Ph-negative MPN in the context of clinical practice in India.

Efficacy and safety of ruxolitinib in Asian patients with myelofibrosis

Myelofibrosis is characterized by progressive cytopenias, bone marrow fibrosis, splenomegaly and severe constitutional symptoms. In the phase 3 Controlled Myelofibrosis Study with Oral JAK Inhibitor Treatment (COMFORT) studies, ruxolitinib, a potent Janus kinase 1 (JAK1)/JAK2 inhibitor, provided substantial improvements in splenomegaly, symptoms, quality-of-life measures and overall survival compared with placebo or best available therapy. No assessments of the efficacy and safety of ruxolitinib have been conducted in Asian patients. Here, we describe results from an open-label, single-arm, phase 2 trial evaluating ruxolitinib in Asian patients with myelofibrosis (n = 120). The primary endpoint was met, with 31.7% of patients achieving a ≥ 35% reduction from baseline spleen volume at week 24. As measured by the 7-day Myelofibrosis Symptom Assessment Form v2.0, 49% of patients achieved a ≥ 50% reduction from baseline in total symptom score. Adverse events were consistent with those seen in the COMFORT studies. Ruxolitinib was well tolerated in Asian patients with myelofibrosis and provided substantial reductions in splenomegaly and improvements in symptoms.

Perspectives on the impact of JAK-inhibitor therapy upon inflammation-mediated comorbidities in myelofibrosis and related neoplasms

Chronic inflammation is suggested to contribute to the Philadelphia-chromosome-negative myeloproliferative neoplasm (MPN) disease initiation and progression, as well as the development of premature atherosclerosis and may drive the development of other cancers in MPNs, both nonhematologic and hematologic. The MPN population has a substantial comorbidity burden, including cerebral, cardiovascular, pulmonary, abdominal, renal, metabolic, skeletal, autoimmune, and chronic inflammatory diseases. This review describes the comorbidities associated with MPNs and the potential impact of early intervention with anti-inflammatory and/or immunomodulatory agents such as JAK-inhibitors, statins, and IFN-α to inhibit cancer progression and reduce MPN-associated comorbidity impact. Early intervention may yield a subset of patients who achieve minimal residual disease, thereby likely reducing the comorbidity burden and improving the cost-effective socioeconomic profile.

Ruxolitinib: a new treatment option for myelofibrosis

Myelofibrosis is a myeloproliferative neoplasm characterized by bone marrow fibrosis and extramedullary hematopoiesis. Evolution of myelofibrosis can lead to life-threatening complications, including transformation to leukemia, thrombotic events, and hemorrhagic episodes. The only curative therapy for myelofibrosis is allogeneic hematopoietic stem cell transplantation. Because this disease manifests primarily in the older population, many patients diagnosed with myelofibrosis are not considered medically fit for such aggressive therapy. Other available medical therapies do not halt disease progression; instead, current treatment strategies have focused on targeting specific symptomology, although with limited efficacy. The lack of effective treatment options for patients with myelofibrosis has rendered this orphan disease state an unmet medical need, and novel approaches to improve outcomes are necessary. Emerging research has identified numerous molecular mutations in patients with myelofibrosis, making this disease a potential candidate for molecularly targeted therapy. The most prevalent mutation identified is a gain-of-function mutation in the Janus kinase (JAK) family, JAK2 V617F, which has been identified in more than half of patients with myelofibrosis. This mutation results in a constitutively active JAK-signal transducer and activator of transcription pathway resulting in dysregulated cellular proliferation and hematopoiesis. Ruxolitinib is a small-molecule inhibitor of JAK1 and JAK2 and recently became the first drug approved by the United States Food and Drug Administration for the treatment of symptomatic intermediate- or high-risk myelofibrosis. In clinical trials, ruxolitinib demonstrated promising efficacy in reducing splenomegaly and myelofibrosis-related symptoms. However, ruxolitinib did not demonstrate disease-modifying potential and is not considered a curative therapeutic option. Adverse events associated with ruxolitinib are primarily hematologic, with thrombocytopenia and anemia being the most common toxicologic events identified. Future research will shed light on whether ruxolitinib in combination with other treatments will further enhance outcomes in myelofibrosis.

Treatment and management of myelofibrosis in the era of JAK inhibitors

Myelofibrosis (MF) can present as a primary disorder or evolve from polycythemia vera (PV) or essential thrombocythemia (ET) to post-PV MF or post-ET MF, respectively. MF is characterized by bone marrow fibrosis, splenomegaly, leukoerythroblastosis, extramedullary hematopoiesis, and a collection of debilitating symptoms. Until recently, the therapeutic options for patients with MF consisted of allogeneic hematopoietic stem cell transplant (alloHSCT), the use of cytoreductive agents (ie, hydroxyurea), splenectomy and splenic irradiation for treatment of splenomegaly, and management of anemia with transfusions, erythropoiesis-stimulating agents (ESAs), androgens, and immunomodulatory agents. However, with increased understanding of the pathogenesis of MF resulting from dysregulated Janus kinase (JAK) signaling, new targeted JAK inhibitor therapies, such as ruxolitinib, are now available. The purpose of this article is to review the clinical features of MF, discuss the use and future of JAK inhibitors, reassess when and how to use conventional MF treatments in the context of JAK inhibitors, and provide a perspective on the future of MF treatment.

Efficacy and safety of pegylated-interferon α-2a in myelofibrosis: a study by the FIM and GEM French cooperative groups

Myeloproliferative neoplasm-related myelofibrosis is associated with cytopenic or proliferative phases, splenomegaly and constitutional symptoms. Few effective treatments are available and small series suggested that interferon could be an option for myelofibrosis therapy. We performed a retrospective study of pegylated-interferon α-2a (Peg-IFNα-2a) therapy in myelofibrosis. Sixty-two patients treated with Peg-IFNα-2a at 17 French and Belgian centres were included. Responses were determined based on the criteria established by the International Working Group for Myelofibrosis Research and Treatment. Mean follow-up was 26 months. Sixteen of 25 anaemic patients (64%) (eight concomitantly receiving recombinant erythropoietin) achieved a complete response and transfusion-independence was obtained in 5/13 patients (38·5%). Constitutional symptoms resolved in 82% of patients. All five leucopenic patients normalized their leucocyte counts, whereas a normal platelet count was obtained in 5/8 thrombocytopenic patients. Splenomegaly was reduced in 46·5% of patients, and complete resolution of thrombocytosis and leucocytosis were observed in 82·8% and 68·8% of patients, respectively. Side effects (mostly haematological) were mainly of grade 1-2. The only factor independently associated with treatment failure was a spleen enlargement of more than 6 cm below the costal margin. In conclusion, Peg-IFNα-2a induced high response rates with acceptable toxicity in a large proportion of patients with primary and secondary myelofibrosis, especially in early phases.

BCR-ABL1-negative chronic myeloid neoplasms: an update on management techniques

Recent discoveries concerning mutations associated with chronic myeloproliferative neoplasms have modified our understanding of the biology of these incurable diseases and guided us to the development of inhibitors active on the constitutively activated JAK-STAT pathway. Concurrently, numerous studies dealt with clinical issues; it led to a revised WHO classification; clarified the role of mutated JAK2 and leukocytosis in the pathogenesis of cardiovascular events; allowed the development of risk prognostic scores and tools for monitoring response to therapy; and resulted in completion of Phase III trials with JAK2 inhibitor in myelofibrosis. All these results hold the promise of improving patient prognostication and therapeutic approach, with the aim of efficiently preventing disease-associated complications and, hopefully, to improve the dismal survival associated with myelofibrosis. This review discusses how to manage, according to current clinical practice, the steps of diagnosis, prognostication and therapeutic choices in myeloproliferative neoplasm patients.

A highly sensitive quantitative real-time PCR assay for determination of mutant JAK2 exon 12 allele burden

Mutations in the Janus kinase 2 (JAK2) gene have become an important identifier for the Philadelphia-chromosome negative chronic myeloproliferative neoplasms. In contrast to the JAK2V617F mutation, the large number of JAK2 exon 12 mutations has challenged the development of quantitative assays. We present a highly sensitive real-time quantitative PCR assay for determination of the mutant allele burden of JAK2 exon 12 mutations. In combination with high resolution melting analysis and sequencing the assay identified six patients carrying previously described JAK2 exon 12 mutations and one novel mutation. Two patients were homozygous with a high mutant allele burden, whereas one of the heterozygous patients had a very low mutant allele burden. The allele burden in the peripheral blood resembled that of the bone marrow, except for the patient with low allele burden. Myeloid and lymphoid cell populations were isolated by cell sorting and quantitative PCR revealed similar mutant allele burdens in CD16+ granulocytes and peripheral blood. The mutations were also detected in B-lymphocytes in half of the patients at a low allele burden. In conclusion, our highly sensitive assay provides an important tool for quantitative monitoring of the mutant allele burden and accordingly also for determining the impact of treatment with interferon-α-2, shown to induce molecular remission in JAK2V617F-positive patients, which may be a future treatment option for JAK2 exon 12-positive patients as well.

Management of myelofibrosis

Myelofibrosis (MF), either primary or arising from previous polycythemia vera (PV) or essential thrombocythemia (ET), is the worst among the chronic myeloproliferative neoplasms in terms of survival and quality of life. Patients with MF have to face several clinical issues that, because of the poor effectiveness of medical therapy, surgery or radiotherapy, represent largely unmet clinical needs. Powerful risk stratification systems, applicable either at diagnosis using the International Prognostic Scoring System (IPSS) or during the variable course of illness using the Dynamic International Prognostic Scoring System (DIPSS) and DIPSS Plus, allow recognition of categories of patients with survival times ranging from decades to < 2 years. These scores are especially important for therapeutic decisions that include allogeneic stem cell transplantation (allogeneic SCT), the only curative approach that still carries a nonnegligible risk of morbidity and mortality even with newest reduced intensity conditioning (RIC) regimens. Discovery of JAK2V617F mutation prompted the development of clinical trials using JAK2 inhibitors; these agents overall have resulted in meaningful symptomatic improvement and reduction of splenomegaly that were otherwise not achievable with conventional therapy. Intriguing differences in the efficacy and tolerability of JAK2 inhibitors are being recognized, which could lead to a nonoverlapping spectrum of activity/safety. Other agents that do not directly target JAK2 and have shown symptomatic efficacy in MF are represented by inhibitors of the mammalian target of rapamycin (mTOR) and histone deacetylases (HDACs). Pomalidomide appears to be particularly active against MF-associated anemia. However, because these agents are all poorly effective in reducing the burden of mutated cells, further advancements are needed to move from enhancing our ability to palliate the disease to arriving at an actual cure for MF.