Assessment of the immunogenicity of gonadotrophins during controlled ovarian stimulation.

PROBLEM: Gonadotrophin hormones are used for the controlled ovarian stimulation (COS) as part of the in vitro fertilization techniques. Therapeutic proteins have the potential to induce an unwanted immune response. METHOD OF STUDY: The presence of anti-FSH, anti-LH and anti-hCG antibodies were determined in patients from two different clinical trials after the repeated administration of hMG or FSH. RESULTS: In the first study, 27 subjects were screening for the presence of anti-FSH antibodies. From the 27 patients, only one patient showed the presence of low levels of antibodies. In a second study, 25 patients were screened for the presence of anti-FSH, anti-LH and anti-hCG antibodies. At the end of the study, no patients showed the presence of antibodies. CONCLUSION: The results of this study suggest that repeated treatment cycles with FSH or hMG in patients undergoing COS for in vitro fertilization can be safely and effectively applied without concerns for immunogenicity.

In vitro metabolism of irosustat, a novel steroid sulfatase inhibitor: interspecies comparison, metabolite identification, and metabolic enzyme identification.

Irosustat is a novel steroid sulfatase inhibitor for hormone-dependent cancer therapy. Its structure is a tricyclic coumarin-based sulfamate that undergoes desulfamoylation in aqueous solution, yielding the sulfamoyl-free derivative, 667-coumarin. The aim of the present work was to study the in vitro metabolism of irosustat, including its metabolic profile in liver microsomes and hepatocytes, the potential species differences, and the identification of the main metabolites and of the enzymes participating in its metabolism. Irosustat was extensively metabolized in vitro, showing similar metabolite profiles among rat, dog, monkey, and humans (both sexes). In liver microsomes, the dog was the species that metabolized irosustat most similarly to metabolism in humans. Marked differences were found between liver microsomes and hepatocytes, meaning that phase I and phase II enzymes contribute to irosustat metabolism. Various monohydroxylated metabolites of irosustat and of 667-coumarin were found in liver microsomes, which mostly involved hydroxylations at the C8, C10, and C12 positions in the cycloheptane ring moiety. 667-Coumarin was formed by degradation but also by non-NADPH-dependent enzymatic hydrolysis, probably catalyzed by microsomal steroid sulfatase. The main metabolites formed by hepatocytes were glucuronide and sulfate conjugates of 667-coumarin and of some of its monohydroxylated metabolites. The major cytochrome P450 enzymes involved in the transformation of irosustat were CYP2C8, CYP2C9, CYP3A4/5, and CYP2E1. Moreover, various phase II enzymes (UDP-glucuronosyltransferases and sulfotransferases) were capable of conjugating many of the metabolites of irosustat and 667-coumarin; however, the clinically relevant isoforms could not be elucidated.