Increased Risk of Lymphoid Neoplasms in Patients with Philadelphia Chromosome–Negative Myeloproliferative Neoplasms

Real-world status of treatment for lymphoid neoplasms developed during the course of myeloproliferative neoplasms in Japan

OBJECTIVES

Patients with myeloproliferative neoplasms (MPNs) are at higher risk of developing secondary malignancies. In this study, we focused on patients with MPNs that complicated lymphoid neoplasms. To analyze the real-world status of lymphoid neoplasm treatment in patients with pre-existing MPNs in Japan, we conducted a multicenter retrospective study.

METHODS

Questionnaires were sent to collect the data on patients who were first diagnosed with either polycythemia vera, essential thrombocythemia or myelofibrosis and who later were complicated with lymphoid neoplasms defined as malignant lymphoma, multiple myeloma, or chronic lymphocytic leukemia/small cell lymphoma.

RESULTS

Twenty-four patients with MPNs complicated by lymphoid neoplasms were enrolled (polycythemia vera, n = 8; essential thrombocythemia, n = 14; and primary myelofibrosis, n = 2). Among these, diffuse large B-cell lymphoma (DLBCL) was the most frequently observed (n = 13, 54.1%). Twelve (92.3%) of the patients with DLBCL received conventional chemotherapy. Among these 12 patients, regarding cytoreductive therapy for MPNs, 8 patients stopped treatment, one continued treatment, and two received a reduced dose. Consequently, most patients were able to receive conventional chemotherapy for DLBCL with a slightly higher dose of granulocyte colony-stimulating factor support than usual without worse outcomes. All 3 patients with multiple myeloma received a standard dose of chemotherapy.

CONCLUSION

Our data indicate that if aggressive lymphoid neoplasms develop during the course of treatment in patients with MPNs, it is acceptable to prioritize chemotherapy for lymphoma.

Molecular landscape of the JAK2 gene in chronic myeloproliferative neoplasm patients from the state of Amazonas, Brazil

JAK2V617F (dbSNP: rs77375493) is the most frequent and most-studied variant in BCR::ABL1 negative myeloproliferative neoplasms and in the JAK2 gene. The present study aimed to molecularly characterize variants in the complete coding region of the JAK2 gene in patients with BCR::ABL1 negative chronic myeloproliferative neoplasms. The study included 97 patients with BCR::ABL1 negative myeloproliferative neoplasms, including polycythemia vera (n=38), essential thrombocythemia (n=55), and myelofibrosis (n=04). Molecular evaluation was performed using conventional PCR and Sanger sequencing to detect variants in the complete coding region of the JAK2 gene. The presence of missense variants in the JAK2 gene including rs907414891, rs2230723, rs77375493 (JAK2V617F), and rs41316003 were identified. The coexistence of variants was detected in polycythemia vera and essential thrombocythemia. Thus, individuals with high JAK2V617F variant allele frequency (≥50% VAF) presented more thrombo-hemorrhagic events and manifestations of splenomegaly compared with those with low JAK2V617F variant allele frequency (<50% VAF). In conclusion, individuals with BCR::ABL1 negative neoplasms can display >1 variant in the JAK2 gene, especially rs2230722, rs2230724, and rs77375493 variants, and those with high JAK2V617F VAF show alterations in the clinical-laboratory profile compared with those with low JAK2V617F VAF.

Current therapies for classic myeloproliferative neoplasms: A focus on pathophysiology and supportive care

PURPOSE

This article concisely evaluates current therapies that have received regulatory approval for the treatment of classic myeloproliferative neoplasms (MPNs). Pertinent pathophysiology and supportive care are discussed. Emerging therapies are also briefly described.

SUMMARY

MPNs are a heterogeneous group of diseases characterized by acquired abnormalities of hematopoietic stem cells (HSCs), resulting in the generation of transformed myeloid progenitor cells that overproduce mature and immature cells within the myeloid lineage. Mutations in JAK2 and other driver oncogenes are central to the genetic variability of these diseases. Cytoreductive therapies such as hydroxyurea, anagrelide, interferon, and therapeutic phlebotomy aim to lower the risk of thrombotic events without exposing patients to an increased risk of leukemic transformation. However, no comparisons can be made between these therapies, as reduction of thrombotic risk has not been used as an endpoint. On the other hand, Janus kinase (JAK) inhibitors such as ruxolitinib, fedratinib, pacritinib, and momelotinib (an investigational agent at the time of writing) directly target the constitutively activated JAK-signal transducer and activator of transcription (JAK-STAT) pathway of HSCs in the bone marrow. Mutations of genes in the JAK-STAT signaling pathway provide a unifying understanding of MPNs, spur therapeutic innovations, and represent opportunities for pharmacists to optimize mitigation strategies for both disease-related and treatment-related adverse effects.

CONCLUSION

Treatment options for MPNs span a wide range of disease mechanisms. The growth of targeted therapies holds promise for expanding the treatment arsenal for these rare, yet complex diseases and creates opportunities to optimize supportive care for affected patients.

Concurrent Polycythemia Vera with Newly Diagnosed Multiple Myeloma: Case Report and Literature Review

Concurrent polycythemia vera with newly diagnosed multiple myeloma is extremely rare. We described a 70-year-old woman with concurrent polycythemia vera and newly diagnosed multiple myeloma. Genetic testing confirmed the JAK2 V617F mutation for the first time, while determination of serum erythropoietin decreased. A retrospective review of our patient's case was conducted thereafter, and related literature was systemically reviewed. We totally identified eight cases with concurrent polycythemia vera with newly diagnosed multiple myeloma, which were further analyzed and compared. The present case is the first patient of newly diagnosed multiple myeloma with diagnosis of polycythemia vera confirmed by positive JAK2 V617F mutation. Abnormal erythremia, hepatosplenomegaly and thrombosis history suggested comorbidity of polycythemia vera with newly diagnosed multiple myeloma. The bortezomib-based chemotherapy regimen seemed to be effective on controlling the proliferation of erythrocyte. Whereas the pathogenesis of these two entities remains to be further investigated.

Statin use, survival and incidence of thrombosis among older patients with polycythemia vera and essential thrombocythemia

BACKGROUND

Polycythemia vera (PV) and essential thrombocythemia (ET) are linked to increased risk of cardiovascular morbidity and mortality. In addition to the reduction in of arterial thrombotic events, statins may prevent venous thrombosis including among patients with cancer. As previous registry- and claims-based studies revealed that the use of statins may improve the survival of patients with various malignancies we evaluated their impact on outcomes of older adults with PV and ET.

METHODS

We identified 4010 older adults (aged 66-99 years at diagnosis) with PV (n = 1809) and ET (n = 2201) in a population-based cohort study using the Surveillance, Epidemiology, and End Results-Medicare database with median follow-up of 3.92 (interquartile range: 2.58-5.75) years. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) approaches were utilized to assess potential association between statins and overall survival. Multivariable competing risk models with death as a competing risk were used to evaluate possible relationship between statins and the incidence of thrombosis.

RESULTS

55.8% of the patients used statins within the first year after PV/ET diagnosis, and statin use was associated with a 22% reduction in all-cause mortality (PSM: hazard ratio [HR] = 0.78, 95% confidence interval [CI]: 0.63-0.98, p = 0.03; IPTW: HR = 0.79, 95% CI: 0.64-0.97, p = 0.03). Statins also reduced the risk of thrombosis in this patient population (PSM: HR = 0.63, 95% CI: 0.51-0.78, p < 0.01; IPTW: HR = 0.57, 95% CI: 0.49-0.66, p < 0.01) as well as in PV and ET subgroups.

CONCLUSIONS

These findings suggest that it may be important to incorporate statins into the therapeutic strategy for older adults with PV and ET.

Use of Next Generation Sequencing to Define the Origin of Primary Myelofibrosis

Primary myelofibrosis (PMF) is a chronic myeloproliferative neoplasm (MPN) characterized by progressive bone marrow sclerosis, extra-medullary hematopoiesis, and possible transformation to acute leukemia. In the last decade, the molecular pathogenesis of the disease has been largely uncovered. Particularly, genetic and genomic studies have provided evidence of deregulated oncogenes in PMF as well as in other MPNs. However, the mechanisms through which transformation to either the myeloid or lymphoid blastic phase remain obscure. Particularly, it is still debated whether the disease has origins in a multi-potent hematopoietic stem cells or instead in a commissioned myeloid progenitor. In this study, we aimed to shed light upon this issue by using next generation sequencing (NGS) to study both myeloid and lymphoid cells as well as matched non-neoplastic DNA of PMF patients. Whole exome sequencing revealed that most somatic mutations were the same between myeloid and lymphoid cells, such findings being confirmed by Sanger sequencing. Particularly, we found 126/146 SNVs to be the e same (including JAK2V617F), indicating that most genetic events likely to contribute to disease pathogenesis occurred in a non-commissioned precursor. In contrast, only 9/27 InDels were similar, suggesting that this type of lesion contributed instead to disease progression, occurring at more differentiated stages, or maybe just represented “passenger” lesions, not contributing at all to disease pathogenesis. In conclusion, we showed for the first time that genetic lesions characteristic of PMF occur at an early stage of hematopoietic stem cell differentiation, this being in line with the possible transformation of the disease in either myeloid or lymphoid acute leukemia.

Incidence and risk factors for second malignancies among patients with myeloproliferative neoplasms

OBJECTIVE

The clinical characteristics and survival of patients with myeloproliferative neoplasms (MPNs) with secondary cancer were analyzed to explore the possible risk factors for secondary cancer in MPN patients.

METHODS

The clinical characteristics of 1060 Chinese patients with MPN were retrospectively analyzed. The Kaplan-Meier method was used to analyze the survival. The Cox multivariate regression model was used to analyze the risk factors for developing secondary cancer in patients with MPNs.

RESULTS

The 1060 patients with MPN had a median follow-up of 10 years (range 1-50) and a median age of 55 years (range 21-86), and 497 (45.2%) were male. The proportion of PV, ET, and PMF was 52.2%, 33.5%, and 14.3%, respectively. About 28.1% (298/1060) of 1060 MPN patients died. The median survival times of the PV, ET, and PMF groups were 20, 24, and 12 years, respectively (p < 0.0001). In age- and sex-matched healthy Chinese patients, the standardized incidence ratio (SIR) value of developing secondary cancer in MPN patients was 6.41 (95% CI: 4.90-9.48). The median survival time was 14 years in the MPN with secondary cancer group. The Cox multivariate analysis showed that age ≥ 65 years (p < 0.0001, HR = 5.027, 95% CI [2.823, 8.952]), MF-1 (p = 0.001, HR = 2.887, 95% CI [1.503, 5.545]) were risk factors for developing secondary cancer.

CONCLUSIONS

The survival of MPN patients with secondary cancer was significantly worse than that of patients without secondary cancer. Compared with normal subjects, MPN patients had a 6.41-fold increased risk of developing secondary cancer, and age ≥ 65 years and MF-1 were risk factors for developing secondary cancer in MPN patients.

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

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

Coexistence of Trisomy 8 and 13 in a Newly Diagnosed Patient With Diffuse Large B Cell Non-Hodgkin Lymphoma and Acute Myeloid Leukemia Secondary to Primary Myelofibrosis

Concomitant diagnosis of non-Hodgkin lymphoma (NHL) and acute myeloid leukemia secondary to chronic myeloproliferative neoplasms (MPNs) is rarely reported. Patients with MPNs may have a second neoplasm, and the risk of lymphoid line neoplasms is 2.5-3.5 times for lymphoid line neoplasms. The explanation for this association is the genetic instability of hematopoietic progenitors in MPNs. An 80-year-old Caucasian man, with many comorbidities, presents for physical asthenia, sweating. The right inguinal adenopathy was known one month before the examination. The patient was diagnosed concomitantly with diffuse large B cell lymphoma (DLBCL) and acute myeloid leukemia (AML) secondary to primary myelofibrosis (PMF) and presented trisomy 8, trisomy 13, and triple-negative PMF status. The patient initially received two well-tolerated R mini CHOP series. This type of treatment was selected to treat DLBCL for one unfit patient for intensive chemotherapy due to his age and comorbidities. R mini CHOP administration was followed by severe aplasia that lasted approximately two weeks followed by severe thrombocytosis that reached 4000 x109/L, and Thromboreductin recommendation was mandatory. The result of the treatment was a partial response but with severe adverse events like neutropenia G4, due to the delay of the treatment the patient lost the response. It was mandatory to select another treatment line and the chosen was venetoclax; it was selected for the simultaneous treatment of DLBCL and the underlying AML. It was obtained a significant reduction in the size of the inguinal lymph node block in two weeks of treatment. Severe neutropenia was diagnosed and complicated with sepsis. The evolution is unfavorable with the installation of multiple organ dysfunction. The presence of a complex karyotype (trisomy 8, trisomy 13) in a patient with myeloid metaplasia with triple-negative PMF was associated with blast transformation and severe thrombocytosis. The patient was diagnosed concomitantly with DLBCL, making the therapeutic decision difficult. Venetoclax has been shown to be useful in the treatment of DLBCL but has been associated with severe neutropenia, which has led to infectious complications.

Philadelphia-positive acute lymphoblastic leukemia in a case of MPL p.(W515L) variant essential thrombocythemia: case report and literature review

Acute lymphoblastic leukemia (ALL) arising in preexisting myeloproliferative neoplasms (MPN) is rare with historical cases unable to differentiate between concomitant malignancies or leukemic transformation. Here, we report a case of patient with Philadelphia positive B lymphoblastic leukemia (Ph+ALL) who developed from MPL-mutated essential thrombocythemia (ET) 13 years after initial presentation. Molecular studies showed the discrepancy between the high percentage of lymphocyte blasts (91%) and the low MPL p.(W515L) variant allele frequency (2.59%) at diagnosis in the bone marrow, indicating that the Ph+ALL clone did not originate from the ET clone carrying the MPL p.(W515L) variant. After the treatment of a new tyrosine kinase inhibitor flumatinib and prednisolone, cytogenetic and molecular remission had been achieved rapidly and followed by the recovery of original ET manifestation. Although relapsed eventually, this is still a very rare case of simultaneous presence of two cytogenetics abnormalities and evolution of MPL p.(W515L) variant ET to Ph+ALL and may provide evidence to illustrate the clonal relationship of MPN and post-MPN ALL.

Risk of mortality and second malignancies in primary myelofibrosis before and after ruxolitinib approval

BACKGROUND

Primary myelofibrosis (PMF) is associated with morbidity and mortality. Ruxolitinib gained US FDA approval for treatment of intermediate/high-risk PMF in November 2011. We evaluated differences in survival and second primary malignancy (SPM) incidence among US PMF patients in the years before and after ruxolitinib approval.

METHODS

We conducted a retrospective study utilizing the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER)-18 database for PMF patients. We divided patients into five-year cohorts pre- (2007-2011) and post-ruxolitinib (2012-2016) approval and compared relative survival rates (RSRs) to the standard population and standardized incidence rates (SIRs) of SPMs between cohorts.

RESULTS

We included 2020 patients diagnosed with PMF from 2007-2016 in this study. There was no difference in the four-year RSRs between cohorts (54 % vs. 57 %, p = 0.776). More patients developed SPMs in the post-ruxolitinib cohort (8% vs. 6%, p = 0.041). The majority of SPMs were hematologic with higher incidence of AML transformation in the post-ruxolitinib cohort (SIR 125.29 vs. 70.55).

CONCLUSIONS

PMF prognosis remains poor in the years following ruxolitinib's approval. SPM incidence including AML transformation is higher in the years after approval. Further studies are needed to determine the true impact of ruxolitnib on population outcomes.

Co-Occurrence of Myeloid and Lymphoid Neoplasms: Clinical Characterization and Impact on Outcome. A Single-Center Cohort Study

The co-occurrence of myeloid neoplasms and lymphoproliferative diseases (LPDs) has been epidemiologically described, particularly in myeloproliferative neoplasms (MPNs). However, the clinical features of these patients are poorly known. In this study, we evaluated a single-center cohort of 44 patients with a diagnosis of myeloid and LPD focusing on clinical features, therapy requirement, and outcome. The two diagnoses were concomitant in 32% of patients, while myeloid disease preceded LPD in 52% of cases (after a median of 37 months, 6-318), and LPD preceded myeloid neoplasm in 16% (after a median of 41 months, 5-242). The most prevalent LPD was non-Hodgkin lymphoma (50%), particularly lymphoplasmacytic lymphoma (54.5%), followed by chronic lymphocytic leukemia (27%), plasma cell dyscrasias (18.2%), and rarer associations such as Hodgkin lymphoma and Erdheim-Chester disease. Overall, 80% of BCR-ABL1-negative MPN patients required a myeloid-specific treatment and LPD received therapy in 45.5% of cases. Seven subjects experienced vascular events, 13 a grade >/= 3 infectious episode (9 pneumonias, 3 urinary tract infection, and 1 sepsis), and 9 developed a solid tumor. Finally, nine patients died due to solid tumor (four), leukemic progression (two), infectious complications (two), and brain bleeding (one). Longer survival was observed in younger patients (p = 0.001), with better performance status (p = 0.02) and in the presence of driver mutations (p = 0.003). Contrarily, a worse survival was significantly associated with the occurrence of infections (p < 0.0001). These data suggest that in subjects with co-occurrence of myeloid and lymphoid neoplasms, high medical surveillance for infectious complications is needed, along with patient education, since they may negatively impact outcome.

New Horizons in Myeloproliferative Neoplasms Treatment: A Review of Current and Future Therapeutic Options

Philadelphia-negative myeloproliferative neoplasms (MPN) are aggressive diseases characterized by clonal proliferation of myeloid stem cells. The clonal process leads to excessive red cells production, platelets production, and bone marrow fibrosis. According to the phenotype, MPN can be classified as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). MPN patients have shortened survival due to the increased risk of thrombosis, hemorrhages, and transformation to acute myeloid leukemia (AML). Prognosis is variable, with a shorter life expectancy in myelofibrosis. Currently, drug therapy can reduce symptoms, splenomegaly, and risk of thrombosis. Still, some patients can be resistant or intolerant to the treatment. At the same time, allogeneic stem cell transplant (ASCT) is the only treatment modality with the potential to cure the disease. Nevertheless, the ASCT is reserved for high-risk leukemic progression patients due to the risk of treatment-related death and comorbidity. Therefore, there is a need for new drugs that can eradicate clonal hematopoiesis and prevent progression to more aggressive myeloid neoplasms. Thanks to the better understanding of the disease’s molecular pathogenesis, many new potentially disease-modifying drugs have been developed and are currently in clinical trials. This review explores the most promising new drugs currently in clinical trials.

Primary Immune Thrombocytopenia and Essential Thrombocythemia: So Different and yet Somehow Similar-Cases Series and a Review of the Literature

This article collects several published cases in which immune thrombocytopenic purpura (ITP) is followed by essential thrombocythemia (ET) and vice versa. This surprising clinical condition is possible, but very rare and difficult to diagnose and manage. We have made an attempt to analyse the possible causes of the sequential appearance of ITP and ET taking into consideration the following: alteration of the thrombopoietin (TPO) receptor, the role of autoimmunity and inflammation, and cytokine modulation. A better understanding of these interactions may provide opportunities to determine predisposing factors and aid in finding new treatment modalities both for ITP and ET patients.

Concomitant Essential Thrombocythemia and Mature B -Lymphoproliferative Disorder in a Patient

A-64-year old male presented with cough, weight loss, and maculopapular rash for 15-20 days. On examination, he was found to have cervical lymphadenopathy and splenomegaly. His leukocyte count was 62.1x10⁹/L, platelets were 1169x10⁹/L and LDH was 816 IU/L. Peripheral blood film showed a leukoerythroblastic picture with thrombocytosis. He was started on hydroxyurea and allopurinol. Subsequently, bone marrow evaluation was done which depicted increased lymphoid cells with an M:E ratio of 4:1. Cellular areas exhibited an increase in myeloid precursors along with prominent lymphoid cells and abundant megakaryocytes. Immunohistochemistry showed an increase in B-lymphocytes. Grade MF-2 reticulin fibrosis was noted. Overall findings suggested essential thrombocythemia (ET). On flow cytometry, CD45-positive lymphoid cells population was 31% and showed reactivity to Pan-B-markers with lambda light chain restriction. Janus Kinase 2 (JAK 2) mutation was detected while BCR-ABL1 translocation was negative. A diagnosis of ET progressing to myelofibrosis and mature B-lymphoproliferative disorder was made. Hydroxyurea and allopurinol were stopped while ruxolitinib was introduced and 2.5 years later he remains stable on this treatment.

T-cell Acute Lymphoblastic Leukemia in a Patient with Pre-existing Essential Thrombocythemia: A Case Report and Literature Review

The occurrence of T–cell acute lymphoblastic leukemia (T–ALL), on a background of preexisting Philadelphia–negative Myeloproliferative neoplasm is rare. Among the few reported cases where no deep molecular sequencing was performed, it was difficult to ascertain whether these leukemia's occurred de-novo or were due to the clonal progression of underlying MPN. We present a case of a 49–year-old man with a history of essential thrombocythemia who subsequently developed T–ALL. By utilizing next generation sequencing we were able to determine that these two entities originated from two distinct clones and were likely random events. We report the outcome and review the literature.

Polycythemia Vera Associated with Pulmonary Hypertension and Diffuse Large B-Cell Lymphoma: A Case Report

BACKGROUND Myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), are associated with pulmonary hypertension (PH) and malignant lymphomas. Although the underlying mechanisms have not been completely clarified, it has been suggested that the Janus kinase 2 (JAK2) mutation, which is frequently identified in PV, can be involved in the development and/or progression of these distinct diseases in patients with MPNs. However, no reports have described the coexistence of PH and malignant lymphoma in patients with MPNs. CASE REPORT A 79-year-old man being treated for PV for 27 years and PH for 5 years was hospitalized due to severe dyspnea at rest. His soluble interleukin-2 receptor levels gradually increased and the chest computed tomography showed remarkable progression of the lung lesions and an enlargement of the mediastinal and axillary lymph nodes. A lymph node biopsy was performed and the patient was diagnosed with diffuse large B-cell lymphoma (DLBCL). Owing to his poor condition, chemotherapy was not initiated, and he died on the 89th day of hospitalization. The pathological autopsy revealed the destruction of alveolar structures with neoplastic space-occupying lesions of DLBCL. Multifactorial features of PH associated with MPNs, including the intimal thickening of pulmonary arteries accompanied by megakaryocytes and obstructed pulmonary arteries with organized thrombi in the lung tissue specimens, were observed. We found a JAK2 mutation based on a genetic analysis of the patient's bone marrow. CONCLUSIONS We present the rare case of a patient who had PV with a JAK2 mutation, which coexisted with PH and DLBCL, and he developed severe refractory respiratory failure.

BRAFV600E mutation in the wrong place: a case of concomitant polycythemia vera, hairy cell leukemia, and thyroid adenoma

BACKGROUND

Polycythemia vera (PV) is one of the Philadelphia-negative myeloproliferative neoplasms (MPN), characterized by a pan-myelosis with an erythroid-predominant proliferation mainly driven by somatic JAK2V617F gain-of-function mutation. Hairy cell leukemia (HCL) is a rare B-cell lineage lymphoproliferative disease (LPD) with a typic immunophenotypic profile. BRAFV600E, leading to constitutive activation of the RAF/MEK/ERK signalling pathway and increased cell proliferation, is identified as the driver mutation in almost all cases. Although the risk of developing an LPD is significantly increased in patients with MPN compared with the general population, few cases of co-occurring PV and HCL are reported to date. BRAF is one of the most frequently mutated oncogenes in human cancer and some point mutations were identified in multiple neoplasms in addition to HCL, including follicular and papillary thyroid adenoma and carcinoma.

CASE PRESENTATION

Here we report a molecular diagnostic challenge in a woman with a concomitant diagnosis of JAK2V617F PV, BRAFV600E HCL, and HRASQ61K thyroid follicular adenoma.

CONCLUSION

In the age of molecular and precision medicine, this case underlines the importance of integrating molecular results with clinical, radiologic, cytologic, and histopathologic investigations.

The safety of JAK kinase inhibitors for the treatment of myelofibrosis

INTRODUCTION

During the last decade, the development of small molecule inhibitors of Janus kinases (JAKi) contributed to revolutionize the therapeutic landscape of myelofibrosis (MF). JAKi proved to be effective in controlling disease-related symptoms and splenomegaly with remarkable inter-drug variability. However, in some cases the border between clinical efficacy of JAKi and dose-dependent toxicities is narrow leading to sub-optimal dose modifications and/or treatment discontinuation.

AREAS COVERED

In the current review, the authors aimed at providing a comprehensive review of the safety profile of JAKi that are currently approved or in advanced clinical development. Also, a short discussion of promising JAKi in early clinical evaluation and molecules 'lost' early in clinical development is provided. Finally, we discuss the possible strategies aimed at strengthening the safety of JAKi while improving the therapeutic efficacy.

EXPERT OPINION

Overall, JAKi display a satisfactory risk-benefit ratio, with main toxicities being gastrointestinal or related to the myelo/immunosuppressive effects, generally mild and easily manageable. However, JAKi may be associated with potentially life-threatening toxicities, such as neurological and infectious events. Thus, many efforts are needed in order to optimize JAKi-based therapeutic strategies without burdening patient safety. This could be attempted through drug combinations or the development of more selective molecules.

Second primary malignancy in myelofibrosis patients treated with ruxolitinib

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

Risks of Solid and Lymphoid Malignancies in Patients with Myeloproliferative Neoplasms: Clinical Implications

Simple Summary

Patients with chronic myeloproliferative neoplasms (MPNs) such as polycythemia vera and essential thrombocythemia have an elevated risk of acute leukemia. Recently, it has been recognized that the risk of solid cancers is also increased. In the past decade, several studies have compared cancer frequency in patients with MPNs with the general population. In our study, we present results sampled from 12 previous studies, totaling more than 65,000 patients with MPNs identified through large registries. Patients with MPNs were compared to the age/sex-matched general population. Our results show that risk of new cancers is 1.5–3.0-fold elevated in patients with MPNs. In particular, lymphomas and cancers of the skin, lung, kidney, and thyroid gland occur more frequently. The difference in cancer occurrence is highest in the age group 60–79 years. Our results indicate that clinical follow up of patients with MPNs should include awareness of the increased cancer risk.

Abstract

In the past decade, several studies have reported that patients with chronic myeloproliferative neoplasms (MPNs) have an increased risk of second solid cancer or lymphoid hematological cancer. In this qualitative review study, we present results from studies that report on these cancer risks in comparison to cancer incidences in the general population or a control group. Our literature search identified 12 such studies published in the period 2009–2018 including analysis of more than 65,000 patients. The results showed that risk of solid cancer is 1.5- to 3.0-fold elevated and the risk of lymphoid hematological cancer is 2.5- to 3.5-fold elevated in patients with MPNs compared to the general population. These elevated risks apply to all MPN subtypes. For solid cancers, particularly risks of skin cancer, lung cancer, thyroid cancer, and kidney cancer are elevated. The largest difference in cancer risk between patients with MPN and the general population is seen in patients below 80 years. Cancer prognosis is negatively affected due to cardiovascular events, thrombosis, and infections by a concurrent MPN diagnosis mainly among patients with localized cancer. Our review emphasizes that clinicians caring for patients with MPNs should be aware of the very well-documented increased risk of second non-myeloid cancers.

Myeloproliferative and lymphoproliferative malignancies occurring in the same patient: a nationwide discovery cohort

Myeloid and lymphoid malignancies are postulated to have distinct pathogenetic mechanisms. The recent observation that patients with a myeloproliferative neoplasm have an increased risk of developing lymphoproliferative malignancy has challenged this assumption. We collected a nationwide cohort of patients with both malignancies. Patients diagnosed in 1990-2015 were identified through the national Danish Pathology Registry. We identified 599 patients with myeloproliferative neoplasm and a concomitant or subsequent diagnosis of lymphoma. Histopathological review of the diagnostic samples from each patient led to a final cohort of 97 individuals with confirmed dual diagnoses of myeloproliferative neoplasm and lymphoma. The age range at diagnosis was 19-94 years (median: 71 years). To avoid the inclusion of cases of therapy-induced myeloproliferative neoplasm occurring in patients previously treated for lymphoma, only patients with myeloproliferative neoplasm diagnosed unequivocally before the development of lymphoma were included. The average time interval between the diagnoses of the two malignancies was 1.5 years. In the majority of patients (90%) both diagnoses were established within 5 years from each other. Among the lymphoma entities, the frequency of peripheral T-cell lymphomas was markedly increased. Interestingly, all but one of the T-cell lymphomas were of angioimmunoblastic type. These findings suggest that myeloproliferative neoplasm and lymphoproliferative malignancy developing in the same patient may have common pathogenetic events, possibly already at progenitor level. We believe that the molecular characterization of the newly developed biorepository will help to highlight the mechanisms driving the genesis and clonal evolution of these hematopoietic malignancies.

JAK Inhibition for the Treatment of Myelofibrosis: Limitations and Future Perspectives

The 2011 approval of ruxolitinib ushered in the Janus kinase (JAK) inhibitor era in the treatment of myelofibrosis (MF), and 2019 saw the US approval of fedratinib. The first therapeutic agents approved by regulatory authorities for MF, these drugs attenuate the overactive JAK-signal transducer and activator of transcription (STAT) signaling universally present in these patients, translating into major clinical benefits in terms of spleen shrinkage and symptom improvement. These, in turn, confer a survival advantage on patients with advanced disease, demonstrated in the case of ruxolitinib, for which long-term follow-up data are available. However, JAK inhibitors do not improve cytopenias in most patients, have relatively modest effects on bone marrow fibrosis and driver mutation allele burden, and clinical resistance eventually develops. Furthermore, they do not modify the risk of transformation to blast phase; indeed, their mechanism of action may be more anti-inflammatory than truly disease-modifying. This has spurred interest in rational combinations of JAK inhibitors with other agents that may improve cytopenias and drugs that could potentially modify the natural history of MF. Newer JAK inhibitors that are distinguished from ruxolitinib and fedratinib by their ability to improve anemia (eg, momelotinib) or safety and efficacy in severely thrombocytopenic patients (eg, pacritinib) are in phase 3 clinical trials. There is also interest in developing inhibitors that are highly selective for mutant JAK2, as well as "type II" JAK2 inhibitors. Overall, although current JAK inhibitors have limitations, they will likely continue to form the backbone of MF therapy for the foreseeable future.

Arterial thrombosis in Philadelphia-negative myeloproliferative neoplasms predicts second cancer: a case-control study

Patients with Philadelphia-negative myeloproliferative neoplasm (MPN) are prone to the development of second cancers, but the factors associated with these events have been poorly explored. In an international nested case-control study, we recruited 647 patients with carcinoma, nonmelanoma skin cancer, hematological second cancer, and melanoma diagnosed concurrently or after MPN diagnosis. Up to 3 control patients without a history of cancer and matched with each case for center, sex, age at MPN diagnosis, date of diagnosis, and MPN disease duration were included (n = 1234). Cases were comparable to controls for MPN type, driver mutations and cardiovascular risk factors. The frequency of thrombosis preceding MPN was similar for cases and controls (P = .462). Thrombotic events after MPN and before second cancer were higher in cases than in controls (11.6% vs 8.1%; P = .013), because of a higher proportion of arterial thromboses (6.2% vs 3.7%; P = .015). After adjustment for confounders, the occurrence of arterial thrombosis remained independently associated with the risk of carcinoma (odds ratio, 1.97; 95% confidence interval, 1.14-3.41), suggesting that MPN patients experiencing arterial events after MPN diagnosis deserve careful clinical surveillance for early detection of carcinoma. This study was registered at www.clinicaltrials.gov as NCT03745378.

Second cancers in MPN: Survival analysis from an international study

One out of ten patients with Philadelphia-negative myeloproliferative neoplasms (MPN) develop a second cancer (SC): in such patients we aimed at assessing the survival impact of SC itself and of MPN-specific therapies. Data were therefore extracted from an international nested case-control study, recruiting 798 patients with SC diagnosed concurrently or after the MPN. Overall, 2995 person-years (PYs) were accumulated and mortality rate (MR) since SC diagnosis was 5.9 (5.1-6.9) deaths for every 100 PYs. A "poor prognosis" SC (stomach, esophagus, liver, pancreas, lung, ovary, head-and-neck or nervous system, osteosarcomas, multiple myeloma, aggressive lymphoma, acute leukemia) was reported in 26.3% of the patients and was the cause of death in 65% of them (MR 11.0/100 PYs). In contrast, patients with a "non-poor prognosis" SC (NPPSC) incurred a MR of 4.6/100 PYs: 31% of the deaths were attributed to SC and 15% to MPN evolution. At multivariable analysis, death after SC diagnosis was independently predicted (HR and 95% CI) by patient age greater than 70 years (2.68; 1.88-3.81), the SC prognostic group (2.57; 1.86-3.55), SC relapse (1.53; 10.6-2.21), MPN evolution (2.72; 1.84-4.02), anemia at SC diagnosis (2.32; 1.49-3.59), exposure to hydroxyurea (1.89; 1.26-2.85) and to ruxolitinib (3.63; 1.97-6.71). Aspirin was protective for patients with a NPPSC (0.60; 0.38-0.95). In conclusion, SC is a relevant cause of death competing with MPN evolution. Prospective data are awaited to confirm the role of cytoreductive and anti-platelet drugs in modulating patient survival after the occurrence of a SC.

The development of T-cell malignancies in patients with pre-existing myeloproliferative neoplasms: a report of three cases

Secondary acute myeloid leukaemia complicating the natural disease course of pre-existing Philadelphia chromosome-negative myeloproliferative neoplasms (PN-MPN) is well documented and associated with treatment challenges and significant morbidity. The incidence of a T-cell malignancy developing in patients with pre-existing PN-MPN is uncommon, with one case documented in the literature. We present two cases of angioimmunoblastic T-cell lymphoma (AITL) and one case of T-cell acute lymphoblastic leukaemia (T-ALL) that developed in patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF), respectively. All malignancies were advanced at diagnosis and exhibited disease progression, regardless of the mutational status of the underlying ET/PMF, presence of cytogenetic abnormalities, type of T-cell neoplasm or systemic chemotherapy utilised. The median time to diagnosis of AITL or T-ALL from the onset of MPN was 4.5 years (range: 6 months-10 years). This single institutional case series demonstrates the possibility of an association between T-cell neoplasms and PN-MPNs.

Myeloproliferative and lymphoproliferative disorders: State of the art

Myeloproliferative neoplasms (MPNs), including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are clonal disorders complicated mainly by vascular events and transformation to myelofibrosis (for PV and ET) or leukemia. Although secondary malignancies, in particular, lymphoproliferative disorders (LPNs), are rare, they occur at a higher frequency than found in the general population, and there has been recent scientific discussion regarding a hypothetical relationship between treatment with JAK inhibitors in MPN and the risk of development of LPN. This has prompted increased interest regarding the coexistence of MPN and LPN. This review focuses on the role of JAK2 and the JAK/STAT pathway in MPN and LPN, whether there is a role for the genetic background in the occurrence of both MPN and LPN and whether there is a role for cytoreductive drugs in the occurrence of both MPN and LPN. Furthermore, whether an increased risk of lymphoma development is limited to patients who receive the JAK inhibitor ruxolitinib, is a more general phenomenon that occurs following JAK1/2 inhibition or is associated with preferential JAK1 or JAK2 targeting is discussed.

Coexistence of Myeloid and Lymphoid Neoplasms: A Single-Center Experience

The coexistence of a myeloid and a lymphoid neoplasm in the same patient is a rare finding. We retrospectively searched the records of the Hematology Division of the Second Department of Internal Medicine and Research Institute at Attikon University General Hospital of Athens from 2003 to 2018. Nine cases have been identified in a total of 244 BCR-/ABL1- negative MPN and 25 MDS/MPN patients and 1062 LPD patients referred to our institution between 2003 and 2018. Each case is distinct in the diversity of myeloid and lymphoid entities, the chronological occurrence of the two neoplasms, and the patient clinical course. All of them exhibit myeloproliferative (6 JAK2 V617F-positive cases) and lymphoproliferative features, with 1 monoclonal B-cell lymphocytosis (MBL), 3 B-chronic lymphocytic leukemias (B-CLL), 3 B-non-Hodgkin lymphomas (B-NHL), 1 multiple myeloma (MM), and 1 light and heavy deposition disease (LHCDD), while in three cases myelodysplasia is also present. The challenges in identifying and dealing with these rare situations in everyday clinical practice are depicted in this article.

Second cancer in Philadelphia negative myeloproliferative neoplasms (MPN-K). A nested case-control study

We conducted a large international nested case-control study including 1881 patients with Philadelphia-negative myeloproliferative neoplasms (MPN). Cases (n = 647) were patients with second cancer (SC: carcinoma, non-melanoma skin cancer, hematological second cancer, and melanoma) and controls (n = 1234) were patients without SC, matched with cases for sex, age at MPN diagnosis, date of MPN diagnosis, and MPN disease duration. The aim was to evaluate the risk of SC after exposure to cytoreductive drugs. Patients exposed to hydroxyurea (HU) (median: 3 years) had a risk of SC similar to unexposed patients (OR = 1.06, 95% CI 0.82-1.38). In contrast, in cancer-specific stratified multivariable analysis, HU had two-fold higher risk of non-melanoma (NM) skin cancer (OR = 2.28, 95% CI 1.15-4.51). A significantly higher risk of NM-skin cancer was also documented for pipobroman (OR = 3.74, 95% CI 1.00-14.01), ruxolitinib (OR = 3.87, 95% CI 1.18-12.75), and for drug combination (OR = 3.47, 95% CI 1.55-7.75). These three drugs did not show excess risk of carcinoma and hematological second cancer compared with unexposed patients. Exposure to interferon, busulfan, and anagrelide did not increase the risk. In summary, while it is reassuring that no excess of carcinoma was documented, a careful dermatologic active surveillance before and during the course of treatments is recommended.

Characteristics of patients with myeloproliferative neoplasms with lymphoma, with or without JAK inhibitor therapy

There is a Blood Commentary on this article in this issue.

Central Nervous System Lymphoma Harboring the JAK2 V617F Mutation That Developed after a 20-year History of Polycythemia Vera

A 78-year-old man who had a 20-year history of polycythemia vera (PV) with a JAK2 V617F mutation presented with gradually progressive disturbance of consciousness. Hyper-intense lesions in the peri-lateral ventricular area and left cerebellar hemisphere were observed by T2-weighted and fluid-attenuated inversion recovery magnetic resonance imaging. Cytologic and genetic analyses of the lymphoma cells obtained from his cerebrospinal fluid established the diagnosis of B-cell lymphoma. No lesions outside of the brain were recognized. Because of his poor general condition, he was not treated actively. A postmortem analysis revealed a JAK2 V617F mutation in the lymphoma cells, suggesting their origin was a PV clone.

Chronic Lymphocytic Leukemia and Myelofibrosis

Background

Chronic lymphocytic lymphoma (CLL) can be associated with several malignancies, but rarely with myelofibrosis. Only isolated case reports in the literature described the association between CLL and primary myelofibrosis (PMF) in the same patient.

Objectives

We describe a case of CLL characterized by the development of PMF and a review of literature.

Methods

We describe an 86-year-old female diagnosed as having CLL and followed by the development of splenomegaly and progressively rising LDH levels 27 months later. A bone marrow biopsy was consistent with the diagnosis of PMF, with positive JAK-2 V617F mutation. We also review the clinical and molecular characteristics of patients with CLL and PMF.

Results

Patients with CLL and PMF are usually older. A lead diagnosis of CLL harbored by PMF is the most common clinical course, although concomitant diseases may occur in 31.7% of patients. JAK-2 V617F mutation can be found in 48.7% of patients.

Conclusion

This case reported here constitutes an unusual situation of CLL characterized by the development of PMF. Etiologic and pathogenic associations-the role of t (1; 6) and JAK-2 V617F mutation-are discussed.

Aggressive B-cell lymphomas in patients with myelofibrosis receiving JAK1/2 inhibitor therapy

Inhibition of Janus-kinase 1/2 (JAK1/2) is a mainstay to treat myeloproliferative neoplasms (MPN). Sporadic observations reported the co-incidence of B-cell non-Hodgkin lymphomas during treatment of MPN with JAK1/2 inhibitors. We assessed 626 patients with MPN, including 69 with myelofibrosis receiving JAK1/2 inhibitors for lymphoma development. B-cell lymphomas evolved in 4 (5.8%) of 69 patients receiving JAK1/2 inhibition compared with 2 (0.36%) of 557 with conventional treatment (16-fold increased risk). A similar 15-fold increase was observed in an independent cohort of 929 patients with MPN. Considering primary myelofibrosis only (N = 216), 3 lymphomas were observed in 31 inhibitor-treated patients (9.7%) vs 1 (0.54%) of 185 control patients. Lymphomas were of aggressive B-cell type, extranodal, or leukemic with high MYC expression in the absence of JAK2 V617F or other MPN-associated mutations. Median time from initiation of inhibitor therapy to lymphoma diagnosis was 25 months. Clonal immunoglobulin gene rearrangements were already detected in the bone marrow during myelofibrosis in 16.3% of patients. Lymphomas occurring during JAK1/2 inhibitor treatment were preceded by a preexisting B-cell clone in all 3 patients tested. Sequencing verified clonal identity in 2 patients. The effects of JAK1/2 inhibition were mirrored in Stat1^-/- mice: 16 of 24 mice developed a spontaneous myeloid hyperplasia with the concomitant presence of aberrant B cells. Transplantations of bone marrow from diseased mice unmasked the outgrowth of a malignant B-cell clone evolving into aggressive B-cell leukemia-lymphoma. We conclude that JAK/STAT1 pathway inhibition in myelofibrosis is associated with an elevated frequency of aggressive B-cell lymphomas. Detection of a preexisting B-cell clone may identify individuals at risk.

Lymphoproliferative disorders in patients with chronic myeloproliferative neoplasms: A systematic review

Patients with a Ph-negative myeloproliferative neoplasm (MPN) may harbor or develop lymphoproliferative disorders (LPD), however, the clinical and molecular determinants of MPN and LPD co-occurrence are still uncertain. To systematically pool the available knowledge, we conducted a scoping review of literature published since January 2005 and analyzed single-patient clinical data from 50 papers reporting 214 individuals harboring both MPN and LPD. Patients had been diagnosed essential thrombocythemia (44%), polycythemia vera (29%), or myelofibrosis (23%) at a median age of 67 years (26-94): half of them incurred a LPD after a median of 72 months from MPN diagnosis, while in 20% the LPD diagnosis was antecedent or synchronous. Patients mainly incurred indolent LPD, particularly chronic lymphocytic leukemia (CLL), while aggressive lymphomas and multiple myeloma were a relevant portion of the LPDs occurring in the follow-up of MPN. CLL was preferentially diagnosed in PV patients and was associated with a very high male-to-female ratio, as well as an older age at MPN diagnosis. On converse, multiple myeloma was rarely reported in PV patients and was preferentially diagnosed in female patients not harboring the JAK2 V617F mutation. Based on the 46 cases reporting follow-up data, median survival after MPN diagnosis was 96 months. This thorough review of published evidence confirms that LPD are relevant clinical events in the history of MPN patients. Controlled studies are needed to better refine individuals at higher risk of developing LPD, to support surveillance programs and to avoid therapies possibly favoring LPD.

Neutropenia caused by hairy cell leukemia in a patient with myelofibrosis secondary to polycythemia vera: a case report

BACKGROUND

Polycythemia vera is a myeloproliferative disease that sometimes evolves to myelofibrosis, causing splenomegaly and neutropenia. In this case report, we describe a patient with polycythemia vera and unexplained neutropenia who later turned out to also have hairy cell leukemia.

CASE PRESENTATION

A middle-aged Caucasian man with polycythemia vera presented to our hospital with chronic mouth ulcers. Later he developed leukopenia and pancytopenia. Bone marrow biopsies showed fibrosis. Further morphological analyses of bone marrow and blood smears revealed probable transformation into acute myeloid leukemia. However, there were also cells indicating hairy cell leukemia. Morphological and immunohistochemical analyses later confirmed the presence of hairy cell leukemia in biopsies that had been present for 3 years. Treatment with cladribine temporarily reversed the patient's neutropenia.

CONCLUSIONS

Hairy cell leukemia may mimic development to myelofibrosis in patients with polycythemia vera.

Second malignancies in patients with myeloproliferative neoplasms: a population-based cohort study of 9379 patients

To determine the risk of a wide range of second malignancies in patients with myeloproliferative neoplasms (MPNs), we conducted a large population-based study and compared the results to matched controls. From national Swedish registers, 9379 patients with MPNs diagnosed between 1973 and 2009, and 35,682 matched controls were identified as well as information on second malignancies, with follow-up until 2010. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were calculated using Cox regression and a flexible parametric model. There was a significantly increased risk of any non-hematologic cancer with HR of 1.6 (95% CI: 1.5-1.7). The HRs for non-melanoma skin cancer was 2.8 (2.4-3.3), kidney cancer 2.8 (2.0-4.0), brain cancer 2.8 (1.9-4.2), endocrine cancers 2.5 (1.6-3.8), malignant melanoma 1.9 (1.4-2.7), pancreas cancer 1.8 (1.2-2.6), lung cancer 1.7 (1.4-2.2), and head and neck cancer 1.7 (1.2-2.6). The HR of second malignancies was similar across all MPN subtypes, sex, and calendar periods of MPN diagnosis. The risk of developing a hematologic malignancy was also significantly increased; the HR for acute myeloid leukemia was 46.0 (32.6-64.9) and for lymphoma 2.6 (2.0-3.3). In conclusion, our study provides robust population-based support of an increased cancer risk in MPN patients.

Role of treatment on the development of secondary malignancies in patients with essential thrombocythemia

Aim of this study is to explore the role of different treatments on the development of secondary malignancies (SMs) in a large cohort of essential thrombocythemia (ET) patients. We report the experience of a regional cooperative group in a real‐life cohort of 1026 patients with ET. We divided our population into five different groups: group 0, no treatment; group 1, hydroxyurea (HU); group 2, alkylating agents (ALK); group 3, ALK + HU sequentially or in combination; and group 4, anagrelide (ANA) and/or α‐interferon (IFN) only. Patients from groups 1, 2, and 3 could also have been treated either with ANA and/or IFN in their medical history, considering these drugs not to have an additional cytotoxic potential. In all, 63 of the 1026 patients (6%) developed 64 SM during the follow‐up, after a median time of 50 months (range: 2–158) from diagnosis. In univariate analysis, a statistically significant difference was found only for gender (P = 0.035) and age (P = 0.0001). In multivariate analysis, a statistically significant difference was maintained for both gender and age (gender HR1.7 [CI 95% 1.037–2.818] P = 0.035; age HR 4.190 [CI 95% 2.308–7.607] P = 0.0001). The impact of different treatments on SMs development was not statistically significant. In our series of 1026 ET patients, diagnosed and followed during a 30‐year period, the different therapies administered, comprising HU and ALK, do not appear to have impacted on the development of SM. A similar rate of SMs was observed also in untreated patients. The only two variables which showed a statistical significance were male gender and age >60 years.