Genotoxic assessment and toxicity evaluation of peginesatide in CByB6F1 hybrid mice

Genotoxic and mutagenic studies of teratogens in developing rat and mouse

In this review, genotoxic and mutagenic effects of teratogenic chemical agents in both rat and mouse have been reviewed. Of these chemicals, 97 are drugs and 33 are pesticides or belong to other groups. Large literature searches were conducted to determine the effects of chemicals on chromosome abnormalities, sister chromatid exchanges, and micronucleus formation in experimental animals such as rats and mice. In addition, studies that include unscheduled DNA synthesis, DNA adduct formations, and gene mutations, which help to determine the genotoxicity or mutagenicity of chemicals, have been reviewed. It has been estimated that 46.87% of teratogenic drugs and 48.48% of teratogenic pesticides are positive in all tests. So, all of the teratogens involved in this group have genotoxic and mutagenic effects. On the other hand, 36.45% of the drugs and 21.21% of the pesticides have been found to give negative results in at least one test, with the majority of the tests giving positive results. However, only 4.16% of the drugs and 18.18% of the pesticides were determined to give negative results in the majority of the tests. Among tests with major negative results, 12.50% of the teratogenic drugs and 12.12% of the teratogenic pesticides were negative in all conducted tests.

Erythropoietin and the heart: physiological effects and the therapeutic perspective

Erythropoietin (Epo) has been thought to act exclusively on erythroid progenitor cells. The identification of Epo receptor (EpoR) in non-haematopoietic cells and tissues including neurons, astrocytes, microglia, immune cells, cancer cell lines, endothelial cells, bone marrow stromal cells, as well as cells of myocardium, reproductive system, gastrointestinal tract, kidney, pancreas and skeletal muscle indicates that Epo has pleiotropic actions. Epo shows signals through protein kinases, anti-apoptotic proteins and transcription factors. In light of interest of administering recombinant human erythropoietin (rhEpo) and its analogues for limiting infarct size and left ventricular (LV) remodelling after acute myocardial infarction (AMI) in humans, the foremost studies utilising rhEpo are reviewed. The putative mechanisms involved in Epo-induced cardioprotection are related to the antiapoptotic, anti-inflammatory and angiogenic effects of Epo. Thus, cardioprotective potentials of rhEpo are reviewed in this article by focusing on clinical applicability. An overview of non-haematopoietic Epo analogues, which are a reliable alternative to the classic EpoR agonists and may prevent undesired side effects, is also provided.

Peginesatide for the treatment of renal disease-induced anemia

INTRODUCTION

Erythropoiesis-stimulating agents (ESAs) are the mainstay of treatment in anemic chronic kidney disease (CKD) patients. A tailored ESA therapy should combine maximal efficacy and safety with greatest convenience in dosing. Peginesatide, recently approved in the US for once-monthly dosing in adult patients on dialysis, is a promising novel PEGylated erythropoietin-mimetic peptide for the treatment of renal disease-induced anemia.

AREAS COVERED

Published animal and human studies that evaluated the pharmacodynamics, pharmacokinetics, clinical efficacy and safety of peginesatide were critically analyzed.

EXPERT OPINION

Peginesatide has a well-studied pharmacological and immunological profile, and latest published data favor the use of peginesatide in place of epoetin in dialysis patients. A more detailed evaluation of its safety profile particularly in trials with CKD patients not requiring dialysis is urgently needed, as peginesatide could be a perfect treatment solution for these patients. In addition, clinical long-term data and results from supplemental studies, e.g., with the PEGylated continuous erythropoietin receptor activator as comparator, should briefly follow. The fate of peginesatide on the highly competitive ESA market is currently not predictable and depends on safety and efficacy results of upcoming trials as well as finally on market and price policy.

Peginesatide clearance, distribution, metabolism, and excretion in monkeys following intravenous administration

Peginesatide, a polyethylene glycol (PEG)ylated peptide-based erythropoiesis-stimulating agent, stimulates the erythropoietin receptor dimer that governs erythropoiesis. Studies were designed to determine the erythropoietic response, pharmacokinetics (PK), tissue distribution, metabolism, and excretion of peginesatide in nonhuman primates following a single i.v. dose. The PK profile of peginesatide (0.1-5 mg/kg) is characterized by low, dose-dependent plasma clearance; small volume of distribution; and long half-life. The peginesatide PK profile following a single i.v. dose is consistent with the sustained erythropoiesis. Biodistribution quantitative whole-body autoradiography demonstrated high peginesatide levels in bone marrow (i.e., primary hematopoietic site) as well as other known hematopoietic sites persisting through at least 3 weeks at 2.1 mg/kg. Microautoradiography analysis at 48 hours postdose revealed uniform and high distribution of radioactivity in the bone marrow and splenic red pulp with less extensive distribution in the renal cortex (glomeruli, associated ducts, interstitial cells). Radioactivity in the kidney was most prominent in the outer medullary and papillary interstitium. At 2 weeks after dosing, cumulative radioactivity recovery in the urine and feces was 60 and 7% of the administered dose, respectively, with most of the radioactivity associated with the parent molecule. In conclusion, the PK characteristics are consistent with a PEGylated peptide of a 45-kDa molecular mass, specifically low volume of distribution and long half-life. Drug was localized principally to hematopoietic sites, and nonspecific tissue retention was not observed. The nonhuman primate data indicate that peginesatide is metabolically stable and primarily excreted in the urine.