Erythropoiesis Equivalence, Pharmacokinetics and Immune Response following Repeat Hematide™ Administration in Cynomolgus Monkeys

Abstract

Hematide™ is a synthetic PEGylated peptidic erythropoiesis stimulating agent (ESA) that is presently being developed for the correction of anemia in patients with chronic renal failure. Unlike currently marketed ESAs, Hematide does not possess any sequence homology to erythropoietin (EPO) and has not elicited moribund immune responses in animal safety studies thereby allowing the generation of a robust safety package. Animals administered marketed ESAs develop anti-EPO antibodies that null the effect of the administered ESA and neutralize endogenous EPO, resulting in severe anemia that precludes the interpretation of chronic safety studies. The primary objective of this study is to determine whether Hematide-specific antibodies are generated when male monkeys are exposed to high Hematide doses (10 mg/kg, intravenous [IV] and subcutaneous [SC]) administered at frequent dosing intervals (every two weeks) for a total of 9 doses; secondary objectives are to evaluate whether developed antibodies impact pharmacokinetics (PK) and pharmacology. In this study, no Hematide-specific antibodies were detected. Hematide exhibits a prolonged plasma half-life and slow clearance by either IV or SC administration. Hematide induced significant erythropoiesis with reticulocytosis and subsequent increases in red blood cells, hematocrit and hemoglobin (Hgb) levels. No erythropoietic differences were noted between the IV and the SC dosed groups with mean ± SD Hgb levels of 20.9 ± 2.5 and 20.3 ± 2.1 g/dL, respectively, occurring on Day 48, corresponding to Hgb increases of 6.5 and 6.7 g/dL, respectively, over pre-dose levels. In conclusion, Hematide is a potent erythropoiesis stimulating agent that exhibits plasma persistence in monkeys. Similar erythropoietic responses were produced following IV and SC administration. The absence of antibody development suggests that Hematide, at the doses and regimen described, has a low immunogenic potential in cynomolgus monkeys.