ganirelix and abarelix

Early studies on gonadotrophin-releasing hormone (GnRH) antagonists pointed out histamine-mediated anaphylactic reactions as a potential adverse effect of these drug candidates. In this study we have compared the histamine-releasing potential of four approved and marketed antagonists, degarelix, cetrorelix, abarelix and ganirelix in an ex vivo model of human skin samples.. Human skin samples were obtained during cosmetic plastic surgery and kept in oxygenated saline solution. The samples were incubated either without or at different concentrations of the antagonists (3, 30 or 300 µg ml(-1) for all, except for ganirelix 1, 10 or 100 µg ml(-1) ). The drug-induced effect was expressed as the increase relative to basal release. The histamine-releasing capacity of the skin was verified by a universal histamine releaser, compound 40/80.. Degarelix had no significant effect on basal histamine release in the 3 to 300 µg ml(-1) concentration range. The effect of ganirelix was moderate causing a nonsignificant increase of 81 ± 27% at the 100 µg ml(-1) concentration. At 30 and 300 µg ml(-1) concentrations abarelix (143 ± 29% and 362 ± 58%, respectively, P < 0.05) and cetrorelix (228 ± 111% and 279 ± 46%, respectively, P < 0.05) caused significantly increased histamine release.. In this ex vivo human skin model, degarelix displayed the lowest capacity to release histamine followed by ganirelix, abarelix and cetrorelix. These findings may provide indirect hints as to the relative likelihood of systemic anaphylactic reactions in clinical settings.

Topics: Gonadotropin-Releasing Hormone; Histamine; Histamine Release; Humans; Oligopeptides; Skin

Three antagonists of gonadotrophin-releasing hormone are currently clinically available. Cetrorelix (Cetrotide) and ganirelix (Orgalutran/Antagon) have been safely used in assisted reproduction since 1999 and 2000 respectively. The structurally similar abarelix (Plenaxis) has been approved for the therapy of advanced androgen sensitive prostate cancer. However, due to the occurrence of allergic reactions, its use is restricted to only a subgroup of patients. These allergic side effects may not be due to abarelix, as the drug itself does not have a strong histamine liberating potential in vitro, but could be attributed to carboxymethylcellulose (CMC), which only Plenaxis, but not Cetrotide or Orgalutran/Antagon contain. CMC is used to obtain the sustained-release characteristics of Plenaxis. Since 1973, numerous case reports and studies have been published regarding allergic reactions and specific immunoglobulin E antibodies against CMC. Thus, the allergic side effects of Plenaxis could be rather due to CMC than to abarelix.

Topics: Female; Fertility Agents, Female; Gonadotropin-Releasing Hormone; Humans; Hypersensitivity; Oligopeptides; Pregnancy