Category Archives: Essential Thrombocythemia

Essential Thrombocythemia A Review

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January 27, 2025

Ayalew Tefferi, MD1; Naseema Gangat, MD1; Giuseppe Gaetano Loscocco, MD2; et al

Abstract

Importance  Essential thrombocythemia, a clonal myeloproliferative neoplasm with excessive platelet production, is associated with an increased risk of thrombosis and bleeding. The annual incidence rate of essential thrombocythemia in the US is 1.5/100 000 persons.

Observations  Patients with essential thrombocythemia have a persistent platelet count of 450 × 109/L or greater. The differential diagnosis includes myeloproliferative neoplasms (polycythemia vera, primary myelofibrosis, chronic myeloid leukemia); inflammatory conditions such as rheumatoid arthritis and systemic lupus erythematosus; infections; splenectomy; iron deficiency anemia; and solid tumors such as lung cancer. Approximately 90% of individuals with essential thrombocythemia have genetic variants that upregulate the JAK-STAT (signal transducer and activator of transcription 5) signaling pathway, including Janus kinase 2 (JAK2, 64%), calreticulin (CALR, 23%), and myeloproliferative leukemia virus oncogene (MPL, 4%). The median age at diagnosis of essential thrombocythemia is 59 years. The median overall survival exceeds 35 years in those diagnosed at 40 years or younger. Patients with essential thrombocythemia are at increased risk of arterial thrombosis (11%), venous thrombosis (7%), and hemorrhagic complications (8%). Thrombosis risk is increased among those with a history of thrombosis, age older than 60 years, a JAK2 gene variant, and cardiovascular risk factors (eg, hypertension, diabetes mellitus, hyperlipidemias, tobacco use). Use of aspirin (81-100 mg/d) is suggested for most patients with essential thrombocythemia to lower thrombosis risk. In a retrospective study of 300 affected patients with a low thrombosis risk (younger than 60 years with no prior thrombosis), those not taking aspirin (100 mg/d) had a risk of arterial thrombosis of 9.4/1000 patient-years and a venous thrombosis risk of 8.2/1000 patient years; cardiovascular risk factors were associated with a higher risk of arterial thrombi (incidence rate ratio, 2.5 [95% CI, 1.02-6.1]), and a JAK2 gene variant was associated with increased risk of venous thrombosis (incidence rate ratio, 4.0 [95% CI, 1.2-12.9]). In a randomized trial of 114 patients at higher risk for thrombosis (age older than 60 years or a prior thrombotic event), cytoreduction with hydroxyurea significantly lowered the risk of arterial or venous thrombotic events compared with no cytoreductive therapy (3.6% vs 24%; P < .01). At a median of 8.5 years from diagnosis, approximately 10% of patients with essential thrombocythemia develop myelofibrosis and about 3% develop acute myeloid leukemia.

Conclusions  Essential thrombocythemia is a rare clonal myeloproliferative neoplasm associated with an increased risk of venous and arterial thrombosis, hemorrhage, myelofibrosis, and acute myeloid leukemia. Based on individual risk factors for thrombosis, persons with essential thrombocythemia may be treated with low-dose aspirin, either alone or in combination with a cytoreductive drug such as hydroxyurea.

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Ropeginterferon Alfa-2b Effective in Phase 3 Essential Thrombocythemia Trial

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By Jordyn Sava
Fact checked by Jason Broderick

The SURPASS-ET trial (NCT04285086), evaluating ropeginterferon alfa-2b (Besremi) in patients with essential thrombocythemia (ET), has achieved its primary endpoint, demonstrating a durable clinical response as defined by modified European Leukemia Net (ELN) criteria.1

In the intent-to-treat (ITT) population, 42.9% (39/91) of patients treated with ropeginterferon alfa-2b had durable responses at 9 and 12 months vs 6.0% (5/83) of patients enrolled in the comparator arm who were treated with anagrelide (Agrylin) (P =.0001).

For the secondary end point, the JAK2 V617F allele burden decreased from 33.7% to 25.3% (-8.4%) in the ropeginterferon alfa-2b group over 12 months, compared with a reduction from 39.7% to 37.3% (-2.4%) in the anagrelide group. These findings indicate that ropeginterferon alfa-2b may provide a more pronounced effect on mitigating the underlying disease pathology relative to anagrelide.

“We are extremely proud of the SURPASS-ET phase 3 study outcome, which shows the potential of [ropeginterferon alfa-2b] as an important new treatment option for patients with ET, a rare blood cancer that drastically increases the risk of heart attack or stroke,” said Ko-Chung Lin, PhD, founder and chief executive officer of PharmaEssentia, in a press release. “The data highlight the broad potential to apply our innovative monopegylated, long-acting interferon technology as a significant step forward for treating ET, and potentially other myeloproliferative neoplasms, with non-chemotherapy treatments.”

For safety, ropeginterferon alfa-2b did not lead to any treatment-related serious adverse events. Overall, the agent had a manageable safety profile.

Full trial results, including additional pharmacokinetics and biomarker data, are expected to be presented at a later date.

“The results of the SURPASS-ET trial are significant,” said Albert Qin, MD, PhD, chief medical officer, PharmaEssentia, in a press release. “ET is a challenging condition associated with symptoms and risks of thrombosis and disease progression. These encouraging results highlight the potential of [ropeginterferon alfa-2b] to provide an effective and tolerable new treatment option that we believe could provide a substantial clinical benefit for patients with ET. We plan to submit these results to the FDA and other regulatory agencies as soon as possible in hopes of providing this potential new treatment option to patients with ET.”

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Phase 3 Trial of Bomedemstat in Essential Thrombocythemia Begins Enrollment

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By Sabrina Serani
Fact checked by Jordyn Sava

A pivotal phase 3 trial (NCT06456346) has initiated to evaluate bomedemstat (MK-3543; IMG-7289), an investigational agent for the treatment of patients with essential thrombocythemia (ET) who have previously not received cytoreductive therapy.1

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control, but also improve their quality of life,” said Gregory Lubiniecki, MD, vice president, global clinical development, Merck Research Laboratories, in a press release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

The Shorespan-007 trial will compare the orally available LSD1 inhibitor bomedemstat with standard-of-care hydroxyurea in patients with treatment-naive ET, the most common myeloproliferative neoplasm. LSD1 is an enzyme that is potentially important for regulating the proliferation of hematopoietic stem cells, as well as the maturation of progenitor cells.

The study’s primary end point is durable clinicohematologic response rate, and secondary end points include duration of hematologic remission, event-free survival, incidence of adverse events, and disease progression rate. Additionally, investigators will be patient-reported outcomes, including fatigue and symptoms.

The FDA previously granted orphan drug and fast track designations to bomedemstat in ET and myelofibrosis, as well as orphan drug designation in acute myeloid leukemia.

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Essential Thrombocythemia Trial Launched Evaluating Bomedemstat

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By Alex Biese
Fact checked by Ashley Chan

A second phase 3 clinical trial has been launched for the investigational oral drug bomedemstat as a potential new treatment for patients with essential thrombocythemia.

The Shorespan-007 clinical trial, according to a news release from bomedemstat manufacturer Merck, will investigate the use of the drug among patients with essential thrombocythemia who have not previously received cytoreductive therapy.

The global trial, which is currently recruiting, will compare bomedemstat to the current standard of care chemotherapy, hydroxyurea. The trial, with 300 participants, is expected to be concluded in May 2029, according to its listing on clinicaltrials.gov.

Essential thrombocythemia, part of a group of blood cancers known as myeloproliferative neoplasms (MPNs), is a rare disease in which the bone marrow produces too many platelets, according to The Leukemia & Lymphoma Society. This disease, The Leukemia & Lymphoma Society explained, can cause blood clots to form in a patient’s blood vessels, in turn resulting in serious health issues such as stroke, heart attack or pulmonary embolism.

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control but also improve their quality of life,” said Dr. Gregory Lubiniecki, vice president of global clinical development for Merck Research Laboratories, in the company’s news release. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

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Merck Announces Phase 3 Trial Initiation for Bomedemstat, an Investigational Candidate for the Treatment of Certain Patients With Essential Thrombocythemia

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August 27, 2024 6:45 am ET

The initiation of a second Phase 3 clinical trial for bomedemstat demonstrates company’s commitment to advancing research in myeloproliferative neoplasms (MPNs)

RAHWAY, N.J.–(BUSINESS WIRE)– Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the initiation of Shorespan-007, a pivotal Phase 3 clinical trial evaluating bomedemstat, an investigational orally available lysine-specific demethylase 1 (LSD1) inhibitor, for the treatment of patients with essential thrombocythemia (ET) who have previously not received cytoreductive therapy. Essential thrombocythemia is a chronic, rare blood disorder and is the most common type of myeloproliferative neoplasm. Global recruitment of the Shorespan-007 trial has begun, with patients now enrolling.

“The standard of care in essential thrombocythemia has remained unchanged for decades, and patients are in need of new options that have the potential to not only improve disease control, but also improve their quality of life,” said Dr. Gregory Lubiniecki, vice president, global clinical development, Merck Research Laboratories. “We are rapidly advancing our clinical development programs with the goal of helping to address these unmet needs and bring more options to patients living with myeloproliferative neoplasms.”

Shorespan-007 is a Phase 3, randomized, double-blind, active comparator-controlled clinical trial ( NCT06456346 ) evaluating bomedemstat compared to the current standard of care chemotherapy, hydroxyurea, for treatment of patients with ET who have previously not received cytoreductive therapy. The trial will enroll approximately 300 patients globally. The primary endpoint of the study is durable clinicohematologic response rate (CHR). Key secondary endpoints include Myelofibrosis Symptom Assessment Form version 4.0 (MFSAF v4.0) individual fatigue symptom item score, Patient-reported Outcomes Measurement Information System (PROMIS) Fatigue SF-7a total fatigue score and MFSAF v4.0 total symptom score. Additional secondary endpoints include duration of hematologic remission, event-free survival and disease progression rate.

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Which Factors Predict Thrombotic Events in Essential Thrombocythemia?

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August 13, 2024

The risk for essential thrombocythemia-related events in patients with the disease can be predicted using currently available clinical data, researchers wrote in a letter to the editor appearing in Blood Cancer Journal.

“Although considered the most indolent myeloproliferative neoplasm (MPN), essential thrombocythemia (ET) is linked to burdensome vasomotor symptoms and potentially fatal complications that include thrombosis, hemorrhage, and disease progression to myelofibrosis and aggressive myeloid neoplasms,” Ghaith Abu-Zeinah, MD, a hematologist and oncologist at the Richard T. Silver Myeloproliferative Neoplasms Center at Weill Cornell Medicine, New York, and colleagues wrote. “Prognostic measures to identify those at greatest risk for thrombosis, progression, and death in ET [events] are important for timely risk-adapted intervention with available treatments, and for development of interventional trials to improve event-free survival [EFS]. But predicting risks of events in ET has been difficult because ET is an uncommon and clinically heterogeneous chronic disease.”

Predicting excess mortality and disease progression related to ET presents challenges because such events often occur decades after a patient is diagnosed, the researchers continued.

“Thus, retrospective analysis of large cohorts with sufficiently long follow-up is required to identify prognostic measures to stratify risk in patients with ET,” they wrote.

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PharmaEssentia Completes Patient Enrollment for Phase 2b EXCEED-ET Trial in Essential Thrombocythemia and Phase 3b ECLIPSE-PV Trial in Polycythemia Vera

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June 25, 2024

PharmaEssentia USA Corporation, a subsidiary of PharmaEssentia Corporation (TWSE: 6446), a global biopharmaceutical innovator based in Taiwan leveraging deep expertise and proven scientific principles to deliver new biologics in hematology, oncology and immunology, today announced completion of enrollment for two clinical trials evaluating its ropeginterferon alfa-2b-njft (BESREMi ® ).

The Phase 2b EXCEED-ET trial (NCT05482971), which is evaluating the effectiveness and safety of ropeginterferon alfa-2b-njft in adult patients with essential thrombocythemia (ET), has exceeded the enrollment goal of 64 patients to include 91 patients. EXCEED-ET is evaluating people diagnosed with ET who are either treatment naïve or have received previous ET treatment with hydroxyurea or anagrelide but require a treatment change due to intolerance or because the previous treatment is no longer effective. This trial is being conducted in the United States and Canada and will use the accelerated dosing schedule (250, 350, 500 mcg). This accelerated dosing schedule has been previously assessed in Asian clinical trials.

The Phase 3b ECLIPSE-PV trial (NCT05481151), assessing the effectiveness and safety of two dosing regimens of ropeginterferon alfa-2b-njft in adult patients with polycythemia vera (PV), has also exceeded the enrollment goal of 100 patients to include 111 patients. ECLIPSE-PV is evaluating two ropeginterferon alfa-2b-njft doses, including the accelerated dosing schedule (as described above) in comparison to the current recommended dosing regimen. The ECLIPSE-PV study is being performed in the United States and Canada.

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Are thrombosis, progression, and survival in ET predictable?

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June 25, 2024

Ghaith Abu-Zeinah, Katie Erdos, Neville Lee, Ahamed Lebbe, Imane Bouhali, Mohammed Khalid, Richard T. Silver & Joseph M. Scandura

Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm (MPN) that originates from a hematopoietic stem cell harboring a mutated JAK2, CALR, or MPL gene, or none of these three mutations (10–15% are “triple negative”). Although considered the most indolent MPN, ET is linked to burdensome vasomotor symptoms, and potentially fatal complications that include thrombosis, hemorrhage, and disease progression to myelofibrosis and aggressive myeloid neoplasms. Prognostic measures to identify those at greatest risk for thrombosis, progression, and death in ET (events) are important for timely risk-adapted intervention with available treatments, and for development of interventional trials to improve event-free survival (EFS). But predicting risks of events in ET has been difficult because ET is an uncommon and clinically heterogenous chronic disease. Predicting progression and excess mortality is even more challenging because these events typically occur decades after ET diagnosis [1]. Thus, retrospective analysis of large cohorts with sufficiently long follow-up is required to identify prognostic measures to stratify risk in patients with ET.

Prognostic models have been developed to assess the risk of thrombosis (IPSET-thrombosis [2]) or overall survival (OS) in ET (IPSET-survival [3], MIPSS-ET [4], and triple A [AAA] [5]). This journal recently published two large retrospective ET cohorts: Gangat et al. at the Mayo Clinic (Mayo) [6] and Loscocco et al. at the Florence Center Research and Innovation of Myeloproliferative Neoplasms (CRIMM) [7]. Both studies confirmed previously identified risk factors for thrombosis, progression and/or death in ET that include older age (Age ≥ 60), male sex, elevated white blood cell count (WBC > 11 × 109/L), elevated absolute neutrophil count (ANC ≥ 8 × 109/L), and low absolute lymphocyte count (ALC < 1.7 × 109/L) at the time of presentation. We evaluated these parameters and current risk models in our cohort of 328 adult patients with ET treated at the Weill Cornell Medicine (WCM) Silver MPN Center over a median follow-up of 6 years [8]. This cohort was rigorously defined according to the 2022 World Health Organization diagnostic criteria and therefore all patients had a diagnostic bone marrow biopsy and had alternative diagnoses scrupulously ruled out. The methods of data collection, retrieval, and analysis used were previously described [9], and cohort characteristics are included in Supplementary Table 1.

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Prospective Analysis Highlights Patterns of Progression to Myelofibrosis Following Essential Thrombocythemia Diagnosis

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June 17, 2024

Author(s): Caroline Seymour

Most patients with essential thrombocythemia (95.7%; 1184/1237) included in an analysis of the prospective, observational MOST study (NCT02953704) did not experience disease progression to myelofibrosis, but those who did were found to have had longer duration of disease, higher white blood cell counts, and lower hemoglobin levels at enrollment, according to findings presented at the 2024 EHA Congress.1

Of the 4.3% (n = 53) of patients who progressed to myelofibrosis, a pathologic diagnosis of the disease or grade 2 or greater fibrosis was the most common indicator (49.1%; n = 26) of disease progression, followed by new or worsening splenomegaly coupled with a combination of high white blood cell counts and low hemoglobin levels and platelet counts (22.6%; n = 12). Additional indicators were death from myelofibrosis, myelodysplastic syndrome (MDS), or acute myeloid leukemia (AML; 11.3%; n = 6) and circulating blasts above 1% with new or worsening splenomegaly (5.7%; n = 3); patients also met at least 2 progression criteria (11.3%; n = 6).

“These findings and further analyses of MOST data will add insight into disease progression in patients with essential thrombocythemia and facilitate clinical management of this patient population,” lead study author Ruben A. Mesa, MD, FACP, president and executive director of Atrium Health Levine Cancer Institute and Atrium Health Wake Forest Baptist Comprehensive Cancer Center, and vice dean of cancer programs at Wake Forest University School of Medicine in Charlotte, North Carolina, and coauthors wrote in the poster.

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ROP-ET: a prospective phase III trial investigating the efficacy and safety of ropeginterferon alfa-2b in essential thrombocythemia patients with limited treatment options

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Jean-Jacques Kiladjian, Francisca Ferrer Marin, Haifa Kathrin Al-Ali, Alberto Alvarez-Larrán, Eloise Beggiato, Maria Bieniaszewska, Massimo Breccia, Veronika Buxhofer-Ausch, Olga Cerna, Ana-Manuela Crisan, Catalin Doru Danaila, Valerio De Stefano, Konstanze Döhner, Victoria Empson, Joanna Gora-Tybor, Martin Griesshammer, Sebastian Grosicki, Paola Guglielmelli, Valentin García-Gutierrez, Florian H. Heidel, Arpád Illés, Ciprian Tomuleasa, Chloe James, Steffen Koschmieder, Maria-Theresa Krauth, Kurt Krejcy, Mihaela-Cornelia Lazaroiu, Jiri Mayer, Zsolt György Nagy, Franck-Emmanuel Nicolini, Francesca Palandri, Vassiliki Pappa, Andreas Johannes Reiter, Tomasz Sacha, Stefanie Schlager, Stefan Schmidt, Evangelos Terpos, Martin Unger, Albert Wölfler, Blanca Xicoy Cirici & Christoph Klade

Abstract

Interferon-based therapies, such as ropeginterferon alfa-2b have emerged as promising disease-modifying agents for myeloproliferative neoplasms (MPNs), including essential thrombocythemia (ET). Current ET treatments aim to normalize hematological parameters and reduce the thrombotic risk, but they do not modify the natural history of the disease and hence, have no impact on disease progression. Ropeginterferon alfa-2b (trade name BESREMi®), a novel, monopegylated interferon alfa-2b with an extended administration interval, has demonstrated a robust and sustained efficacy in polycythemia vera (PV) patients. Given the similarities in disease pathophysiology and treatment goals, ropeginterferon alfa-2b holds promise as a treatment option for ET. The ROP-ET trial is a prospective, multicenter, single-arm phase III study that includes patients with ET who are intolerant or resistant to, and/or are ineligible for current therapies, such as hydroxyurea (HU), anagrelide (ANA), busulfan (BUS) and pipobroman, leaving these patients with limited treatment options. The primary endpoint is a composite response of hematologic parameters and disease-related symptoms, according to modified European LeukemiaNet (ELN) criteria. Secondary endpoints include improvements in symptoms and quality of life, molecular response and the safety profile of ropeginterferon alfa-2b. Over a 3-year period the trial assesses longer term outcomes, particularly the effects on allele burden and clinical outcomes, such as disease-related symptoms, vascular events and disease progression. No prospective clinical trial data exist for ropeginterferon alfa-2b in the planned ET study population and this study will provide new findings that may contribute to advancing the treatment landscape for ET patients with limited alternatives.

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