ABSTRACT
Recurrent problems of patients with myelofibrosis (MF) are cytopenias, debiliating disease-related symptoms and splenomegaly. Whereas the latter are usually addressed by the JAK1/2 inhibitors ruxolitinib and fedratinib, cytopenias often remain critical. Momelotinib, a JAK1/2 inhibitor recently approved for the treatment of anemic MF patients, was shown to improve anemia via a direct inhibition of activin A receptor type I. In this German-wide, multicenter, retrospective analysis the safety and efficacy profile of momelotinib was evaluated in a real world setting within a cohort of 60 MF patients independent of pre-treatment. The median duration of treatment was 12 weeks. As a new, but manageable safety finding, creatinine increase (CTC°1-2) was detected in 10/60 patients (17%). Interestingly, not only hemoglobin levels increased in 84% of patients, but also platelet values (67%). In the cohort of transfusion-dependent individuals (n = 38), transfusion requirement improved in 15 patients (39%) with 8 reaching transfusion independency (21%). Transfusion independency was achieved within a median of 4 weeks (range 2-12). Spleen size decreased in 13/53 individuals (25%) with a median response time of 6 weeks. Thereof, 11 patients had been pre-treated with JAK inhibitor(s) (85%). Clinical improvement was detected in 24/51 symptomatic individuals (47%) with a median response time of 4 weeks. 5 patients stopped treatment due to side effects (8%), 6 patients due to a worsening of clinical symptoms (10%). Taken together, the MoReLife analysis identifies momelotinib as potent and safe therapeutic option also for heavily pre-treated cytopenic MF patients under real world conditions.
ABSTRACT
Hereditary erythrocytosis is a rare hematologic disorder characterized by an excess of red blood cell production. Here we describe a European collaborative study involving a collection of 2,160 patients with erythrocytosis sequenced in ten different laboratories. We focused our study on the EGLN1 gene and identified 39 germline missense variants including one gene deletion in 47 probands. EGLN1 encodes the PHD2 prolyl 4-hydroxylase, a major inhibitor of hypoxia-inducible factor. We performed a comprehensive study to evaluate the causal role of the identified PHD2 variants: (i) in silico studies of localization, conservation, and deleterious effects; (ii) analysis of hematologic parameters of carriers identified in the UK Biobank; (iii) functional studies of the protein activity and stability; and (iv) a comprehensive study of PHD2 splicing. Altogether, these studies allowed the classification of 16 pathogenic or likely pathogenic mutants in a total of 48 patients and relatives. The in silico studies extended to the variants described in the literature showed that a minority of PHD2 variants can be classified as pathogenic (36/96), without any differences from the variants of unknown significance regarding the severity of the developed disease (hematologic parameters and complications). Here, we demonstrated the great value of federating laboratories working on such rare disorders in order to implement the criteria required for genetic classification, a strategy that should be extended to all hereditary hematologic diseases.
Subject(s)
Polycythemia , Humans , Polycythemia/diagnosis , Polycythemia/genetics , Polycythemia/metabolism , Hypoxia-Inducible Factor-Proline Dioxygenases/genetics , Hypoxia-Inducible Factor-Proline Dioxygenases/metabolism , Germ-Line Mutation , Base SequenceABSTRACT
Givosiran is a novel approach to treat patients with acute intermittent porphyrias (AIP) by silencing of ∂-ALA-synthase 1, the first enzyme of heme biosynthesis in the liver. We included two patients in the Envision study who responded clinically well to this treatment. However, in both patients, therapy had to be discontinued because of severe adverse effects: One patient (A) developed local injection reactions which continued to spread all over her body with increasing number of injections and eventually caused a severe systemic allergic reaction. Patient B was hospitalized because of a fulminant pancreatitis. Searching for possible causes, we also measured the patients plasma homocysteine (Hcy) levels in fluoride-containing collection tubes: by LC-MS/MS unexpectedly, plasma Hcy levels were 100 and 200 in patient A and between 100 and 400 µmol/l in patient B. Searching for germline mutations in 10 genes that are relevant for homocysteine metabolism only revealed hetero- and homozygous polymorphisms in the MTHFR gene. Alternatively, an acquired inhibition of cystathionine-beta-synthase which is important for homocysteine metabolism could explain the plasma homocysteine increase. This enzyme is heme-dependent: when we gave heme arginate to our patients, Hcy levels rapidly dropped. Hence, we conclude that inhibition of ∂-ALA-synthase 1 by givosiran causes a drop of free heme in the hepatocyte and therefore the excessive increase of plasma homocysteine. Hyperhomocysteinemia may contribute to the adverse effects seen in givosiran-treated patients which may be due to protein-N-homocysteinylation.
Subject(s)
5-Aminolevulinate Synthetase/antagonists & inhibitors , Acetylgalactosamine/analogs & derivatives , Heme/deficiency , Hyperhomocysteinemia/etiology , Porphyria, Acute Intermittent/drug therapy , Pyrrolidines/therapeutic use , Acetylgalactosamine/adverse effects , Acetylgalactosamine/therapeutic use , Adult , Arginine/therapeutic use , Colitis/etiology , Colon, Sigmoid/pathology , Controlled Clinical Trials as Topic , Drug Hypersensitivity/etiology , Female , Fibrosis , Heme/analysis , Heme/therapeutic use , Hepatocytes/drug effects , Hepatocytes/metabolism , High-Throughput Nucleotide Sequencing , Homocysteine/metabolism , Humans , Hydroxymethylbilane Synthase/blood , Hydroxymethylbilane Synthase/genetics , Male , Models, Biological , Pancreatitis/etiology , Porphyria, Acute Intermittent/blood , Porphyria, Acute Intermittent/complications , Porphyria, Acute Intermittent/genetics , Pyrrolidines/adverse effectsABSTRACT
In Germany, analyses of clinical and laboratory features of patients with acute porphyrias are only available for hereditary coproporphyria (HCP) but not with other acute porphyrias, acute intermittent porphyria (AIP) and variegate porphyria (VP). The aim of the study was to analyze a large cohort of patients with particular focus upon quality of life aspects. Sixty-two individuals from separate families with acute porphyrias (57 AIP, 5 VP) were included into an observational study collecting biochemical, genetic, and clinical data. A questionnaire was designed to complete anamnestic information and to assess the influence on quality of life. Most frequent signs and symptoms or laboratory abnormalities were abdominal colicky pain, red coloration of urine, and hyponatremia. Depression or anxiety was reported by 61% or 52% individuals, respectively. Fatigue was mentioned as the most quality of life-limiting symptom. In 59/61 patients, mutations could be identified. 44% (20/45) had to be admitted to an intensive care unit. Heme arginate was used in 64% (29/45) of patients for treatment of acute attacks at least once and in 33% for long-term treatment with high frequency of administration. Serum creatinine values increased in 47% (7/17) of the patients with recurrent attacks. Our analysis confirms a substantial influence of the diseases on the quality of life on patients. Percentages of urine discoloration and intensive care unit admissions were much higher than in other reports. Long-term treatment with heme arginate requires careful monitoring of iron status and renal values.
Subject(s)
Arginine/administration & dosage , Family , Heme/administration & dosage , Hospitalization , Porphyria, Acute Intermittent , Quality of Life , Surveys and Questionnaires , Adult , Anxiety/drug therapy , Anxiety/genetics , Anxiety/metabolism , Anxiety/psychology , Depression/drug therapy , Depression/genetics , Depression/metabolism , Depression/psychology , Female , Germany , Humans , Male , Porphyria, Acute Intermittent/drug therapy , Porphyria, Acute Intermittent/genetics , Porphyria, Acute Intermittent/metabolism , Porphyria, Acute Intermittent/psychology , Prospective StudiesABSTRACT
OBJECTIVES: To present the Central European Myeloproliferative Neoplasm Organisation (CEMPO) treatment recommendations for polycythaemia vera (PV). METHODS: During meetings held from 2015 through 2017, CEMPO discussed PV and its treatment and recent data. RESULTS: PV is associated with increased risks of thrombosis/thrombo-haemorrhagic complications, fibrotic progression and leukaemic transformation. Presence of Janus kinase (JAK)-2 gene mutations is a diagnostic marker and standard diagnostic criterion. World Health Organization 2016 diagnostic criteria for PV, focusing on haemoglobin levels and bone marrow morphology, are mandatory. PV therapy aims at managing long-term risks of vascular complications and progression towards transformation to acute myeloid leukaemia and myelodysplastic syndrome. Risk stratification for thrombotic complications guides therapeutic decisions. Low-risk patients are treated first line with low-dose aspirin and phlebotomy. Cytoreduction is considered for low-risk (phlebotomy intolerance, severe/progressive symptoms, cardiovascular risk factors) and high-risk patients. Hydroxyurea is suspected of leukaemogenic potential. IFN-α has demonstrated efficacy in many clinical trials; its pegylated form is best tolerated, enabling less frequent administration than standard interferon. Ropeginterferon alfa-2b has been shown to be more efficacious than hydroxyurea. JAK1/JAK2 inhibitor ruxolitinib is approved for hydroxyurea resistant/intolerant patients. CONCLUSIONS: Greater understanding of PV is serving as a platform for new therapy development and treatment response predictors.
ABSTRACT
Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPN) comprise a heterogeneous group of chronic hematologic malignancies. The quality of life, morbidity, and mortality of patients with MPN are primarily affected by disease-related symptoms, thromboembolic and hemorrhagic complications, and progression to myelofibrosis and acute leukemia. Major bleeding represents a common and important complication in MPN, and the incidence of such bleeding events will become even more relevant in the future due to the increasing disease prevalence and survival of MPN patients. This review discusses the causes, differential diagnoses, prevention, and management of bleeding episodes in patients with MPN, aiming at defining updated standards of care in these often challenging situations.
Subject(s)
Hemorrhage/etiology , Hemostatic Techniques , Myeloproliferative Disorders/complications , Anticoagulants/adverse effects , Anticoagulants/therapeutic use , Antineoplastic Agents/adverse effects , Antineoplastic Agents/therapeutic use , Blood Coagulation Factors/therapeutic use , Blood Loss, Surgical/prevention & control , Blood Transfusion , Blood Vessels/drug effects , Blood Vessels/pathology , Clinical Trials as Topic , Contraindications , Deamino Arginine Vasopressin/therapeutic use , Disease Management , Elective Surgical Procedures , Hemorrhage/diagnosis , Hemorrhage/prevention & control , Hemorrhage/therapy , Humans , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/complications , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/drug therapy , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/genetics , Liver/physiopathology , Multicenter Studies as Topic , Myeloproliferative Disorders/drug therapy , Myeloproliferative Disorders/genetics , Platelet Aggregation Inhibitors/adverse effects , Platelet Aggregation Inhibitors/therapeutic use , Platelet Function Tests , Platelet Transfusion , Postoperative Hemorrhage/etiology , Postoperative Hemorrhage/prevention & control , Postoperative Hemorrhage/therapy , Thrombophilia/drug therapy , Thrombophilia/etiology , Tranexamic Acid/therapeutic use , von Willebrand Diseases/etiology , von Willebrand Factor/analysisABSTRACT
High platelet counts in essential thrombocythemia (ET) can be effectively lowered by treatment with either anagrelide or hydroxyurea. In 259 previously untreated, high-risk patients with ET, diagnosed according to the World Health Organization classification system, the efficacy and tolerability of anagrelide compared with hydroxyurea were investigated in a prospective randomized noninferiority phase 3 study in an a priori-ordered hypothesis. Confirmatory proof of the noninferiority of anagrelide was achieved after 6 months using the primary end point criteria and was further confirmed after an observation time of 12 and 36 months for platelet counts, hemoglobin levels, leukocyte counts (P < .001), and ET-related events (HR, 1.19 [95% CI, 0.61-2.30], 1.03 [95% CI, 0.57-1.81], and 0.92 [95% CI, 0.57-1.46], respectively). During the total observation time of 730 patient-years, there was no significant difference between the anagrelide and hydroxyurea group regarding incidences of major arterial (7 vs 8) and venous (2 vs 6) thrombosis, severe bleeding events (5 vs 2), minor arterial (24 vs 20) and venous (3 vs 3) thrombosis and minor bleeding events (18 vs 15), or rates of discontinuation (adverse events 12 vs 15 or lack of response 5 vs 2). Disease transformation into myelofibrosis or secondary leukemia was not reported. Anagrelide as a selective platelet-lowering agent is not inferior compared with hydroxyurea in the prevention of thrombotic complications in patients with ET diagnosed according to the World Health Organization system. This trial was registered at http://www.clinicaltrials.gov as #NCT01065038.
Subject(s)
Hydroxyurea/therapeutic use , Nucleic Acid Synthesis Inhibitors/therapeutic use , Platelet Aggregation Inhibitors/therapeutic use , Quinazolines/therapeutic use , Thrombocythemia, Essential/drug therapy , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Maximum Tolerated Dose , Middle Aged , Prognosis , Prospective Studies , Retrospective Studies , Single-Blind Method , Thrombocythemia, Essential/pathology , World Health Organization , Young AdultABSTRACT
Patients with Philadelphia chromosome-negative myeloproliferative neoplasms (MPN) like polycythemia vera and essential thrombocythemia are at increased risk of arterial and venous thrombosis. Strategies of prevention may consist of platelet aggregation inhibitors and/or cytoreductive agents depending on the underlying disease and the individual risk. Clinical evidence for management of acute venous thromboembolic events in MPN patients is limited. Modality and duration of therapeutic anticoagulation after venous thrombosis has to be evaluated critically with special regard to the increased risk for spontaneous bleeding events associated with the underlying diseases. Both for therapy of the acute event and for secondary prophylaxis, low-molecular-weight heparins should preferentially be used. A prolongation of the therapeutic anticoagulation beyond the usual 3 to 6 months can only be recommended in high-risk settings and after careful evaluation of potential risks and benefits for the individual patient. New direct oral anticoagulants (NOAC) should not preferentially be used due to lack of clinical experience in patients with MPN and potential drug interactions (e.g. with JAK inhibitors). Consequent treatment of the underlying myeloproliferative disease and periodical evaluation of the response to therapy is crucial for optimal secondary prophylaxis of thromboembolic events in those patients.
Subject(s)
Anticoagulants/therapeutic use , Myeloproliferative Disorders/complications , Thrombophilia/drug therapy , Venous Thromboembolism/prevention & control , Anticoagulants/administration & dosage , Anticoagulants/adverse effects , Anticoagulants/pharmacokinetics , Disease Susceptibility , Drug Interactions , Female , Hemorrhage/chemically induced , Hemorrhage/prevention & control , Heparin, Low-Molecular-Weight/administration & dosage , Heparin, Low-Molecular-Weight/adverse effects , Heparin, Low-Molecular-Weight/therapeutic use , Humans , Hydroxyurea/therapeutic use , Incidence , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/blood , Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative/complications , Male , Myeloproliferative Disorders/blood , Myeloproliferative Disorders/therapy , Phlebotomy , Platelet Aggregation Inhibitors/administration & dosage , Platelet Aggregation Inhibitors/adverse effects , Platelet Aggregation Inhibitors/therapeutic use , Postoperative Complications/prevention & control , Pregnancy , Pregnancy Complications, Hematologic/drug therapy , Pregnancy Complications, Hematologic/prevention & control , Preoperative Care , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Quinazolines/therapeutic use , Secondary Prevention , Thrombophilia/etiology , Venous Thromboembolism/epidemiology , von Willebrand Diseases/etiology , von Willebrand Diseases/physiopathologyABSTRACT
Aquagenic pruritus (AP) is a symptom typical for polycythemia vera, but very little is known about its exact frequency, characteristics, influence on quality of life, and proper treatment. Therefore, we investigated these aspects in a large cohort of German patients with polycythemia vera using a patient directed questionnaire. Our analysis revealed that 301 of 441 analyzed patients suffered from AP. In 64.8%, AP occurred on average 2.9 years prior to diagnosis of polycythemia vera. Only in 15.4% did this lead to a hematological investigation. AP occurs primarily on the trunk and proximal parts of the extremities. Most patients complain about itching (71.8%), the remainder about tickling, stinging, or burning sensations. Forty-four patients (14.6%) classified the pruritus as "unbearable." Patients with AP reported reduced global health status and higher fatigue, pain, and dyspnea. Only 24% of patients received pruritus specific treatment for pruritus consisting mostly of histamine antagonists, which ameliorated symptoms in about half of the patients. In 5.6% of patients, polycythemia vera directed therapy (phlebotomy/cytoreduction) resolved the symptoms. In summary, AP is a serious symptom in patients with polycythemia vera, which until recently was difficult to treat. The advent of the novel JAK2 inhibitors, however, may open new ways for therapy.
Subject(s)
Polycythemia Vera , Pruritus , Quality of Life , Surveys and Questionnaires , Adult , Aged , Aged, 80 and over , Female , Histamine Antagonists/administration & dosage , Humans , Male , Middle Aged , Phlebotomy/methods , Polycythemia Vera/complications , Polycythemia Vera/pathology , Polycythemia Vera/physiopathology , Polycythemia Vera/therapy , Pruritus/etiology , Pruritus/pathology , Pruritus/physiopathology , Pruritus/therapyABSTRACT
INTRODUCTION: Acute intermittent porphyria (AIP) is a very rare (orphan) metabolic disorder of porphyrin biosynthesis which is characterized by elevated plasma and urine levels of 5-aminolevulinic acid (5-ALA) and porphobilinogen (PBG). Patients with this disorder which is caused by a germline mutation of the hydroxymethylbilan-synthase (HMBS)-gene have a high risk of primary liver cancer which may be determined by disease activity. The exact mechanism of carcinogenesis of this rare tumor is unknown, however. MATERIALS AND METHODS: We analyzed paraffin-embedded formalin-fixed liver tumor and normal liver specimens of two female AIP patients treated at the Munich EPNET center. One patient had developed hepatocellular carcinoma (HCC), the other intrahepatic cholangiocarcinoma (CCA). Since biallelic inactivation of HMBS had been observed in one study, we used Sanger and next-generation sequencing with a 8 gene porphyria panel plus 6 potential modifier loci to search for mutations in DNA extractions. RESULTS: In the patient with the HCC, we found a second inactivating mutation in the HMBS gene in the tumor but not in the adjacent normal liver tissue. No mutation could be found in the liver tissues of the patient with CCA, however. CONCLUSIONS: Biallelic inactivation of HMBS or protoporphyrinogen-oxidase (PPOX), another enzyme of porphyrin biosynthesis, has been observed in patients with acute porphyrias and liver tumors. We could confirm this in our patient with HCC with a mutation in HMBS but not in the one with CCA. Since 5-ALA can be converted into carcinogenic substances such as 4,5-dioxovaleric acid (DOVA) or 3,6-dihydropyrazine-2,5-dipropanoic acid (= cyclic dimerization product of 5-ALA), local production of these metabolites in hepatic areas with complete loss of HMBS activity may contribute to liver carcinogenesis.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Porphyria, Acute Intermittent , Porphyrins , Female , Humans , Aminolevulinic Acid/urine , Carcinogenesis , Carcinoma, Hepatocellular/genetics , Flavoproteins , Liver Neoplasms/genetics , Mitochondrial Proteins , Porphyria, Acute Intermittent/genetics , Porphyria, Acute Intermittent/pathology , Protoporphyrinogen Oxidase/genetics , AdultABSTRACT
Heme, iron protoporphyrin IX, is one of life's most central molecules. Hence, availability of the enzymatic machinery necessary for its synthesis is crucial for every cell. Consequently, inborn errors of porphyrin metabolism that compromise normal synthesis, namely the family of porphyrias, undermine normal cellular metabolism given that heme has functions in catalytic centers, signal transduction and functional regulation and its synthesis is fully integrated into the center of intermediary metabolism. Very often, diagnosis of porphyrias is difficult and therefore delayed. Therapy can be as complicated. Over the last 50 years, several strategies have been developed: because of its integration with other parts of intermediary metabolism, the infusion of glucose (glucose effect) was one of the first attempts to counterbalance the dysregulation of porphyrin synthesis in porphyrias. Since heme synthesis is impaired, infusional replacement of heme was the next important therapeutic step. Recently, siRNA technology has been introduced in order to downregulate 5-ALA-synthase 1, which contributes to the patho-physiology of these diseases. Moreover, other novel therapies using enzyme protein replacement, mRNA techniques or proteostasis regulators are being developed.
ABSTRACT
INTRODUCTION: Homocysteine is a sulfur-containing amino acid formed in the intermediary metabolism of methionine. Amino acid metabolism and heme biosynthesis pathways are complexly intertwined. Plasma homocysteine elevation, hyperhomocysteinemia (HHcy), has been reported in patients with acute hepatic porphyria (AHP), a family of rare genetic disorders caused by defects in hepatic heme biosynthesis. AREAS COVERED: This article summarizes published case series in which givosiran, a subcutaneously administered small interfering RNA approved for AHP treatment, appeared to exacerbate dysregulated homocysteine metabolism in patients with AHP. A comprehensive exploratory analysis of ENVISION trial data demonstrated that on a population level, givosiran increased homocysteine but with wide interpatient variations, and there is no proof of correlations between HHcy and changes in efficacy or safety of givosiran. EXPERT OPINION: The strong correlation and co-increase of homocysteine and methionine suggest that HHcy associated with givosiran is likely attributable to the impaired trans-sulfuration pathway catalyzed by cystathionine ß-synthase, which uses vitamin B6 as a cofactor. Data-based consensus supports monitoring total plasma homocysteine and vitamin B6, B12, and folate levels before and during givosiran treatment; supplementing with pyridoxine/vitamin B6 in patients with homocysteine levels >100 µmol/L; and involving patients with homocysteine levels >30 µmol/L in decisions to supplement.
Subject(s)
Hyperhomocysteinemia , Porphyrias, Hepatic , Humans , Cystathionine beta-Synthase/genetics , Folic Acid , Heme , Homocysteine , Hyperhomocysteinemia/diagnosis , Hyperhomocysteinemia/drug therapy , Methionine/metabolism , Porphyrias, Hepatic/diagnosis , Porphyrias, Hepatic/drug therapy , Porphyrias, Hepatic/complications , Pyridoxine , RNA, Small Interfering , Sulfur , Vitamin B 6 , Clinical Trials as TopicABSTRACT
BACKGROUND: Severe hereditary coagulation factor XIII deficiency is a rare homozygous bleeding disorder affecting one person in every two million individuals. In contrast, heterozygous factor XIII deficiency is more common, but usually not associated with severe hemorrhage such as intracranial bleeding or hemarthrosis. In most cases, the disease is caused by F13A gene mutations. Causative mutations associated with the F13B gene are rarer. DESIGN AND METHODS: We analyzed ten index patients and three relatives for factor XIII activity using a photometric assay and sequenced their F13A and F13B genes. Additionally, structural analysis of the wild-type protein structure from a previously reported X-ray crystallographic model identified potential structural and functional effects of the missense mutations. RESULTS: All individuals except one were heterozygous for factor XIIIA mutations (average factor XIII activity 51%), while the remaining homozygous individual was found to have severe factor XIII deficiency (<5% of normal factor XIII activity). Eight of the 12 heterozygous patients exhibited a bleeding tendency upon provocation. CONCLUSIONS: The identified missense (Pro289Arg, Arg611His, Asp668Gly) and nonsense (Gly390X, Trp664X) mutations are causative for factor XIII deficiency. A Gly592Ser variant identified in three unrelated index patients, as well as in 200 healthy controls (minor allele frequency 0.005), and two further Tyr167Cys and Arg540Gln variants, represent possible candidates for rare F13A gene polymorphisms since they apparently do not have a significant influence on the structure of the factor XIIIA protein. Future in vitro expression studies of the factor XIII mutations are required to confirm their pathological mechanisms.
Subject(s)
Codon, Nonsense , Factor XIII Deficiency/genetics , Factor XIIIa/chemistry , Factor XIIIa/genetics , Mutation, Missense , Mutation , Adult , Aged , Amino Acid Sequence , Child , Child, Preschool , Crystallography, X-Ray , Factor XIII Deficiency/diagnosis , Female , Humans , Male , Middle Aged , Molecular Sequence Data , Protein Structure, Tertiary/genetics , Sequence Alignment , Young AdultABSTRACT
BACKGROUND: Anagrelide hydrochloride is an anti-thrombotic agent indicated for the treatment of essential thrombocythemia (ET). In various previously published clinical trials of 2 branded formulations of anagrelide in patients with ET at high risk for thrombohemorrhagic events, the rates of adverse events and discontinuation were strikingly divergent between brands. Because the formulations and manufacturers differed, the differences in tolerability, as well as platelet counts, might have been related to differences in pharmacokinetic properties between the 2 formulations. OBJECTIVES: The present series of investigations (1) determined the pharmacokinetic profile of anagrelide and its metabolites; (2) compared the pharmacokinetic profiles of the test and reference formulations of anagrelide; (3) investigated the in vitro release of anagrelide as a marker of intragastric anagrelide release of the test and reference formulations; and (4) compared the platelet-reducing effects of the test and reference formulations in patients with thrombocythemia in 2 longitudinal studies over 4 weeks. METHODS: A series of 4 in vivo studies and 1 in vitro study were conducted. In a pilot, prospective, singledose study in healthy volunteers, the pharmacokinetic properties (C(max), T(max), and AUC(0-infinity)) of a test formulation of anagrelide were assessed using high-performance liquid chromatography analysis of plasma samples. Based on the results from that study, a single-dose, randomized, double-blind, 2-period crossover study in healthy volunteers was conducted to determine bioequivalence of 2 formulations of anagrelide 2 mg/d (taken as 4 capsules). In vitro dissolution properties of the test or reference formulation containing 0.5 mg anagrelide as the active ingredient were studied in an assay mimicking gastrointestinal release. To test for effects on platelet counts of switching from the reference formulation (previous treatment on stable dose for 3 months) to the test formulation, two 4-week longitudinal trials were conducted: one in patients with ET (in Germany), and one in patients with thrombocythemia associated with chronic myeloproliferative disorders (CMPDs) (in Austria). RESULTS: The pilot pharmacokinetic study of the test formulation in 16 volunteers (10 women, 6 men; mean [SD] age, 20.5 [1.5] years; weight, 69.0 [10.0 kg) suggested that anagrelide was metabolized to 3-hydroxyanagrelide (AUC(0-infinity) 50% compared with anagrelide) and the inactive metabolite 2-amino-5,6-dichloro-,4-dihydroquinazolone. The subsequent bioequivalence study in 24 volunteers (14 women, 10 men; mean [SD] age, 23 [4] years; white, 100%; weight, 67.5 [10.2] kg) found that the test formulation was associated with a significantly lower C(max) (point estimation [PE], 66%; 90% CI, 58%-76%; P < 0.001) and AUC(0-infinity) (PE, 77%; 90% CI, 68%-86%; P = 0.001). T(max) values for anagrelide and 3-hydroxyanagrelide were 1 hour longer with the test formulation compared with the reference formulation. The total number of adverse events with the reference formulation was 46; the test formulation, 29 (P = 0.05). In vitro, anagrelide from the reference formulation was immediately released (89.1% at 5 minutes), whereas there was a delayed release (93.6% at 30 minutes) from the test formulation (P < 0.05). In the last 2 studies, 2 cohorts of white patients (cohort 1, 15 patients with ET; 10 women, 5 men; mean [SD] age, 49.0 [10.7] years [range, 31-66 years]; weight, 73.2 [12.6] kg; cohort 2, 19 patients with thrombocythemia associated with CMPD; 12 women, 7 men; age, 62.6 [12.4] years [range, 38-80 years]; weight, 66.1 [13.3] kg) who had received treatment for > or =3 months with the reference formulation were switched to the same dose of the test formulation and maintained on this dose for 4 weeks. Platelet counts did not change significantly from baseline over 4 weeks and stayed within a predefined margin of 150 x 10(3) cells/microL. CONCLUSIONS: The pharmacokinetic properties, adverse event rates, and in vitro dissolution profile differed between the test and reference anagrelide formulations in these healthy volunteers. In patients with ET or thrombocythemia associated with CMPD, platelet counts did not differ significantly from baseline at 4 weeks when subjects were switched from the reference to the test anagrelide formulation.
Subject(s)
Myeloproliferative Disorders/drug therapy , Platelet Aggregation Inhibitors/administration & dosage , Quinazolines/administration & dosage , Thrombocytosis/drug therapy , Adolescent , Adult , Aged , Aged, 80 and over , Area Under Curve , Chromatography, High Pressure Liquid/methods , Chronic Disease , Cross-Over Studies , Double-Blind Method , Female , Humans , Longitudinal Studies , Male , Middle Aged , Myeloproliferative Disorders/physiopathology , Platelet Aggregation Inhibitors/adverse effects , Platelet Aggregation Inhibitors/pharmacokinetics , Platelet Count , Quinazolines/adverse effects , Quinazolines/pharmacokinetics , Randomized Controlled Trials as Topic , Solubility , Therapeutic Equivalency , Thrombocytosis/etiology , Young AdultABSTRACT
Extracellular vesicles (EVs), e.g., exosomes and microvesicles, are one of the main networks of intercellular communication. In myeloproliferative neoplasms, such as polycythemia vera (PV), excess of EVs originating from overabundant blood cells can directly contribute to thrombosis through their procoagulant activity. However, the proteomic composition of these vesicles in PV patients has not been investigated before. In this work, we examined the proteomic composition of serum EVs of PV patients in comparison to healthy controls. We processed EV-enriched serum samples using the Multiple Enzyme Filter Aided Sample Preparation approach (MED-FASP), conducted LC-MS/MS measurements on a Q-Exactive HF-X mass spectrometer, and quantitatively analyzed the absolute concentrations of identified proteins by the Total Protein Approach (TPA). Thirty-eight proteins were present at statistically significant different concentrations between PV patients' study group and healthy controls' group. The main protein components deregulated in PV were primarily related to excessive amounts of cells, increased platelet activation, elevated immune and inflammatory response, and high concentrations of procoagulant and angiogenic agents. Our study provides the first quantitative analysis of the serum EVs' proteome in PV patients. This new knowledge may contribute to a better understanding of the secondary systemic effects of PV disease and further development of diagnostic or therapeutic procedures.
ABSTRACT
Anagrelide is an established therapy for essential thrombocythemia. Common adverse effects have been linked to peak plasma concentrations of anagrelide and its 3OH metabolite. Our study was performed to investigate the pharmacokinetics (PK) of a novel anagrelide extended-release (AER) formulation and its active metabolites. Thirty healthy volunteers were randomized to receive either 2 mg AER (under fasting and fed conditions) or 2 mg commercially available reference product (CARP) in an open-label, 3-way crossover trial with washout periods of 6 days. Plasma concentrations of anagrelide and its active metabolites were assessed by tandem mass spectrometry. The PK differed significantly between all treatment periods. Bioavailability of AER was 55% of the CARP under fasting conditions and 60% under fed conditions. Cmax , AUCt, and AUC∞ were significantly higher and Tmax and T1/2 were significantly shorter after the CARP compared with AER. Food had a significant impact on the PK of AER, increasing the Cmax and AUCt while reducing the T1/2 , plateau, and mean residence time. Both formulations were well tolerated, with a trend toward more frequently occurring adverse events after the CARP. The PK of AER and the CARP differed significantly in all parameters. Food enhanced the bioavailability of AER.
Subject(s)
Fibrinolytic Agents/pharmacokinetics , Food-Drug Interactions , Platelet Aggregation Inhibitors/pharmacokinetics , Quinazolines/pharmacokinetics , Administration, Oral , Adolescent , Adult , Cross-Over Studies , Delayed-Action Preparations/pharmacokinetics , Fasting/metabolism , Female , Fibrinolytic Agents/blood , Healthy Volunteers , Humans , Male , Middle Aged , Platelet Aggregation Inhibitors/blood , Quinazolines/blood , Young AdultABSTRACT
BACKGROUND: Primary thrombocythemia is a rare acquired chronic disorder of the bone marrow which can occur at any age. Diagnosis is based upon elevated platelet counts, morphologically and functionally altered platelets and characteristic bone marrow alterations as well as the exclusion of related myeloproliferative disorders which can also be accompanied by increased platelet counts. Possible disease complications are thromboembolic and hemorrhagic events as well as a transformation into myelofibrosis or acute leukemia. Inhibition of platelet aggregation with aspirin for the prevention of thromboembolic complications is first-line therapy; cytoreductive therapy with drugs such as hydroxyurea or interferon-alpha or thromboreductive therapy with the platelet-reducing agent anagrelide is required when thromboembolic complications are already present at diagnosis (secondary prevention) or when platelet counts are steadily increasing or various additional risk factors are present (primary prevention). Because of the potential adverse effects of the various therapies upon long-term application a strict risk-benefit analysis is mandatory before initiation of therapy. In up to 50% of the patients the recently discovered V617F mutation in the JAK2 gene can be identified which is supposed to be involved in the pathogenesis of this disease. CLINICAL STUDIES: Because of the rarity of primary thrombocythemia thus far only two prospectively randomized studies have been carried out to compare cyto- and thromboreductive therapies. In the British PT1 study the mandatory combination of anagrelide with aspirin was compared with the combination of hydroxyurea and aspirin, in the European ANAHYDRET study monotherapy with hydroxyurea was compared with that of anagrelide. This different study design has caused an intense controversy about the results of these studies obtained thus far. CONCLUSION: Due to the existence of randomized clinical studies expert opinion will, in the future, be increasingly replaced by evidence-based therapy guidelines. The improved knowledge of the molecular basis of the disease because of the discovery of the V617F mutation in the JAK2 gene has improved the molecular diagnosis and opened new avenues to molecular-targeted therapies.