Low-risk polycythemia vera treated with phlebotomies: clinical characteristics, hematologic control and complications in 453 patients from the Spanish Registry of Polycythemia Vera

Pharmacokinetics, pharmacodynamics, and tolerability of an aqueous formulation of rusfertide (PTG-300), a hepcidin mimetic, in healthy volunteers: A double-blind first-in-human study

OBJECTIVES

Rusfertide is a potent peptide mimetic of hepcidin being investigated for the treatment of polycythemia vera. This randomized, placebo-controlled, double-blind study evaluated the safety, pharmacokinetics, and pharmacodynamics of single and repeated subcutaneous doses of an aqueous formulation of rusfertide in healthy adult males.

METHODS

Subjects received single doses of 1, 3, 10, 20, 40, or 80 mg rusfertide or placebo. A separate cohort of subjects received two doses of 40 mg rusfertide or placebo 1 week apart. Blood samples for pharmacokinetics and pharmacodynamics were collected, and adverse events, clinical laboratory tests, 12-lead electrocardiograms, and vital signs were monitored.

RESULTS

Rusfertide was well tolerated. There were no serious or severe treatment-emergent adverse events, and no patterns of clinically important adverse events, or laboratory, vital sign, or electrocardiogram abnormalities. Mean maximum rusfertide plasma concentration (Cmax) and area under the concentration-time curve increased with dose, but less than dose proportionally. Median time to Cmax was 2-4.5 h for 40 and 80 mg rusfertide and 8-24 h for lower doses. Apparent clearance and half-life increased with dose. Single doses of rusfertide 1-80 mg were associated with dose-dependent decreases in serum iron and transferrin-iron saturation.

CONCLUSIONS

Rusfertide was well tolerated and showed dose-dependent pharmacokinetics and pharmacodynamics.

The evolving landscape of polycythemia vera therapies

INTRODUCTION

The treatment landscape of polycythemia vera (PV) has seen major advancements within the last decade including approval of ruxolitinib in the second line setting after hydroxyurea, ropegylated interferon-α2b, and advanced clinical development of a novel class of agents called hepcidin mimetics.

AREAS COVERED

We provide a comprehensive review of the evidence discussing the risk stratification, treatment indications, role and limitations of phlebotomy only approach and pivotal trials covering nuances related to the use of interferon-α (IFN-α), ruxolitinib, hepcidin mimetics and upcoming investigational agents including HDAC and LSD1 inhibitors.

EXPERT OPINION

The research paradigm in PV is slowly shifting from the sole focus on hematocrit control and moving toward disease modification. The discovery of hepcidin mimetics has come as a breakthrough in restoring iron homeostasis, achieving phlebotomy-independence and may lead to improved thrombosis-free survival with stricter hematocrit control. On the other hand, emerging data with IFN- α and ruxolitinib as well as combination of the two agents suggests the potential for achieving molecular remission in a subset of PV patients and long-term follow-up is awaited to validate the correlation of molecular responses with clinically relevant outcomes of progression-free and thrombosis-free survival.

Efficacy and safety outcomes in Japanese patients with low-risk polycythemia vera treated with ropeginterferon alfa-2b

Polycythemia vera (PV) is a Philadelphia chromosome-negative myeloproliferative neoplasm characterized by clonal erythrocytosis. A phase 2 study reported that ropeginterferon alfa-2b is a well-tolerated and effective treatment for PV in Japanese patients. This post hoc analysis of the phase 2 data further evaluated outcomes in patients at low risk of thrombosis (low-risk PV). Among 20 patients with low-risk PV, 60.0% (12/20) and 85.0% (17/20) achieved < 45% hematocrit by weeks 24 and 52, respectively. The proportion of responders with complete hematologic response (CHR) was 60.0% (12/20) at week 52, and the median time to response was 11.9 months. The mean JAK2 V617F allele burden decreased from 75.8% at baseline to 53.7% at week 52. No patient experienced thrombosis or bleeding episodes. All patients experienced treatment-emergent adverse events (TEAEs) related to ropeginterferon alfa-2b, but no grade ≥ 3 TEAEs or deaths related to ropeginterferon alfa-2b occurred, and no new safety concerns arose. This analysis indicated that ropeginterferon alfa-2b may be an effective treatment option for Japanese patients with low-risk PV.

A Review About the Assessment of the Bleeding and Thrombosis Risk for Patients With Myeloproliferative Neoplasms Scheduled for Surgery

Myeloproliferative neoplasms (MPNs) present a unique challenge in surgical management due to their inherent predisposition to both bleeding and thrombosis. MPNs are a heterogenous group of acquired clonal conditions. The three classic MPNs are essential thrombocythemia (ET), myelofibrosis (PMF), and polycythemia vera (PV). All subtypes of MPN are associated with both thrombotic and bleeding complications. There are four risk categories for thrombosis in MPN patients: age, thrombosis history, and JAK-2 mutation. They are further classified as very low, low, intermediate, and high risk. The genetic landscape of MPN is fascinating and complex like all myeloid disorders. Bleeding risk can be assessed through leukocytosis, thrombocytosis, acquired von Willebrand syndrome (AVWS), and a previous history of bleeding in a patient. Risk assessment and perioperative management are important aspects of improving the quality of life and preventing complications in surgeries. Preoperative management includes a risk assessment of venous thromboembolism, use of appropriate pharmacological treatment, platelet count control, and correction and cardiovascular risk factors. This review summarizes the assessment of bleeding and thrombosis risk for patients with MPNs scheduled for surgery. Furthermore, this review discusses various tools that can be used to identify MPN patients at risk of thrombosis prior to surgery.

Concomitant Cerebral Venous Thrombosis and Intracranial Hemorrhages in Presentation of a Patient with Secondary Polycythemia: A Case Report

BACKGROUND Cerebral ischemia and hemorrhages were reported to be the main complications of polycythemia vera (PV). The relationship between PV and increased risk of the cerebrovascular events has been established. Some patients with secondary polycythemia have thromboembolic events comparable to those of PV. However, secondary polycythemia that leads to cerebrovascular events is uncommon. CASE REPORT A 35-year-old man without any prior medical history presented with mild clinical acute ischemic stroke and polycythemia. The patient then showed worsening neurological deficits that were later attributed to the concurrent cerebral venous thrombosis, which led to malignant cerebral infarction with hemorrhagic transformation, and subarachnoid hemorrhage. His polycythemia appeared to be secondary to bacterial infection. The treatments for the secondary polycythemia were first phlebotomy and intravenous hydration, followed by intravenous broad-spectrum antibiotics. PV was excluded because the JAK2 V617F mutation was absent, the patient's peripheral blood smear suggested secondary polycythemia due to bacterial infection, and there were improvements in hemoglobin, erythrocyte count, and hematocrit after intravenous antibiotics. At the 1-month follow-up, he was moderately dependent, and hemoglobin, erythrocyte count, and hematocrit were within normal limits, without receiving any further phlebotomy or cytoreductive agents. CONCLUSIONS This case highlights the plausible causation of secondary polycythemia that could lead to concomitant cerebral thrombosis and hemorrhagic events. The diagnosis of cerebral venous thrombosis should be considered in a patient who presents with headache, focal neurological deficits, polycythemia, and normal head computed tomography scan.

Ropeginterferon versus Standard Therapy for Low-Risk Patients with Polycythemia Vera

BACKGROUND: Whether phlebotomy alone can adequately maintain target hematocrit in patients with low-risk polycythemia vera (PV) remains elusive. METHODS: In a phase 2 open-label randomized trial, we compared ropeginterferon alfa-2b (ropeg; 100 μg every 2 weeks) with phlebotomy only regarding maintenance of a median hematocrit level (≤45%) over 12 months in the absence of progressive disease (primary end point). In follow-up, crossover to the alternative treatment group was allowed if the primary end point was not met. RESULTS: In total, 127 patients were enrolled (ropeg: n=64; standard group: n=63). The primary end point was met in 81% and 51% in the ropeg and standard groups, respectively. Responders continued the assigned treatment until month 24 and maintained response in 83% and 59%, respectively (P=0.02). Ropeg responders less frequently experienced moderate/severe symptoms (33% vs. 67% in the standard group) and palpable splenomegaly (14% vs. 37%) and showed normalization of ferritin levels and blood counts. Nonresponders at 12 months crossed over to the standard (n=9) or ropeg (n=23) group; in patients switched to ropeg only, 7 of 23 met the response criteria in 12 months, and phlebotomy need was high (4.7 per patient per year). Discontinuation because of adverse events occurred in seven patients treated with ropeg. CONCLUSIONS: In this 24-month trial, ropeg was superior to phlebotomy alone in maintaining hematocrit on target. No dose-limiting side effects or toxicities were noted; 9.2% of patients on ropeg and no patients on standard treatment developed neutropenia. (Funded by AOP Health and others; ClinicalTrials.gov number, NCT03003325.)