Histrelin

Advanced prostate cancer patients (n = 17) that received a subcutaneous histrelin implant (Vantas, Endo Pharmaceuticals) had peak serum concentrations of 1.10 ± 0.375 ng/mL (mean ± SD) at 12 hours.^L41715 The continuous subcutaneous release of the histrelin implant was confirmed, as serum levels were sustained throughout the 52-week dosing period. At the end of the 52-week period, the mean serum histrelin concentration was 0.13 ± 0.065 ng/mL.^L41715 In patients that received a second implant at the end of the 52-week period, the serum histrelin concentration in the first eight weeks was similar to the one detected with the first implant. On average, the residual drug content of 41 histrelin implants (Vantas, Endo Pharmaceuticals) was 56.7 ± 7.71 mcg/day over 52 weeks.^L41715 Compared to healthy male volunteers that received a subcutaneous bolus dose, the relative bioavailability of histrelin in patients with prostate cancer and normal renal and hepatic function was 92%.^L41715 In children with central precocious puberty (CPP, n=47) that received a subcutaneous histrelin implant (Supprelin LA, Endo Pharmaceuticals), the median maximum serum histrelin concentration over the study period was 0.43 ng/mL, which is expected to maintain gonadotropins at prepubertal levels.^L41700 There were no pharmacokinetic differences between patients previously treated with luteinizing hormone-releasing hormone (LHRH) agonists and those that had not.^L41700 Food-drug interaction studies have not been performed for histrelin products.L41715,L41700 Serum histrelin concentrations are 50% higher in prostate cancer patients with mild to severe renal impairment compared to those with no renal or hepatic impairment; however, this difference is not considered clinically relevant.^L41715