Single and multi‐dose pharmacology of recombinant and urinary human chorionic gonadotrophin in men

Abstract

AbstractObjectiveHuman choriogonadotrophin (hCG) treatment of gonadotrophin‐deficient infertile men uses hCG of urinary (uhCG) or recombinant (rhCG) origin, but these treatments have not been compared nor are there studies defining rhCG dosing in men.DesignhCG products were studied in randomized cross‐over single‐dose studies of standard (Study 1, 1500 IU and 62.5 µg, respectively) or high (Study 2, 5000 IU and 250 µg) dose and a multi‐dose population pharmacology study of hCG use.ParticipantsEight (Study 1) and seven (Study 2) volunteers in cross‐over and 52 gonadotrophin‐deficient men in the multi‐dose studyMeasurementsIn cross‐over studies, serum testosterone (T), dihydrotestosterone (DHT) and estradiol by liquid chromatography‐mass spectrometry (LCMS) and serum hCG, LH, FSH, SHBG and T (observational study) by immunoassays.ResultsAfter standard and high‐dose injection, serum hCG and testosterone responses had similar timing and peak concentrations except for a mildly lower early (<48 h) serum testosterone with uhCG. In the multi‐dosing study, both hCGs had similar pharmacokinetics (pooled half‐life 5.8 days, p < .001), while serum testosterone concentrations were stable after injection and did not differ between hCG products. Bench testing verified that 20% of pens from 4/10 individuals were used inappropriately.ConclusionsAlthough hCG pharmacokinetics are not formally bioequivalent, the similar pharmacodynamic effects on serum testosterone indicate that at the doses tested both hCGs provide comparable clinical effects. The starting dose of rhCG for treating gonadotrophin‐deficient men should be 62.5 µg (6 clicks) of the rhCG pen.