Follitropin delta in repeated ovarian stimulation for IVF: a controlled, assessor-blind Phase 3 safety trial.

RESEARCH QUESTION: To evaluate the immunogenicity of follitropin delta in repeated ovarian stimulation. DESIGN: Controlled, assessor-blind trial in IVF/intracytoplasmic sperm injection patients undergoing repeated cycles of ovarian stimulation (cycles 2 and 3), following initial stimulation with follitropin delta or follitropin alfa (cycle 1) in a preceding randomized trial. In cycles 2 and 3, 513 and 188 women, respectively, were treated as randomized in cycle 1, with dosing based on ovarian response in the previous cycle. RESULTS: The incidence of treatment-induced anti-FSH antibodies with follitropin delta was 0.8% and 1.1% in cycles 2 and 3, respectively, which was similar to the incidence in cycle 1 (1.1%). No antibodies were of neutralizing capacity. Women with pre-existing anti-FSH antibodies were safely treated with follitropin delta without boosting an immune response. Treatment with follitropin delta and follitropin alfa gave similar outcomes for mean number of oocytes retrieved (9.2 versus 8.6 [cycle 2]; 8.3 versus 8.9 [cycle 3]), ongoing pregnancy (27.8% versus 25.7%; 27.4% versus 28.0%) and live birth rates (27.4% versus 25.3%; 26.3% versus 26.9%). The presence of anti-FSH antibodies did not affect the ovarian response. CONCLUSIONS: The trial demonstrated the low immunogenicity potential of follitropin delta in repeated ovarian stimulation, and confirmed the appropriateness of the follitropin delta dosing regimen in repeated cycles, with documented efficacy and safety.

In vitro and in vivo human metabolism of degarelix, a gonadotropin-releasing hormone receptor blocker.

Degarelix is a decapeptide that shows high affinity/selectivity to human gonadotropin-releasing hormone receptors and has been approved for the treatment of advanced prostate cancer in the United States, European Union, and Japan. To investigate the metabolism of degarelix in humans, in vitro metabolism was addressed in liver tissue and in vivo metabolism was studied in plasma and excreta samples collected in clinical studies. In addition, drug transporter interaction potential of degarelix with selected efflux transporters and uptake transporters was studied using in vitro membrane vesicle-based assays and whole cell-based assays. In vitro degradation was observed in fresh hepatocytes; less than 25% of the initial concentration of degarelix remained after incubation at 37°C for 2 hours. One metabolite was detected, representing a truncated nonapeptide of degarelix. The same metabolite was also detected at low concentrations in plasma. The in vivo investigations also showed that degarelix is excreted unchanged via the urine but is undergoing extensive sequential peptidic degradation during its elimination via the hepato-biliary pathway. No unique human metabolites of degarelix were detected in the circulation or in the excreta. Degarelix did not show any interaction with selected efflux transporters and uptake transporters up to concentrations representing 200 times the clinical concentration. Because degarelix does not seem to interact with the cytochrome P450 enzyme system as substrate, inhibitor, or inducer and does not show any interaction with hepatic and renal uptake and efflux transporters, the risk for pharmacokinetic drug-drug interactions with this compound is highly unlikely.

'Less is More': defining modern bioanalysis.

The 4th Open Symposium of the European Bioanalytical Forum entitled 'Less is More' was held on 16-18 November 2011 at the Hesperia Tower Hotel, Barcelona, Spain. More than 50 interesting presentations were delivered covering areas with interest for the small- and large-molecule community - biomarker validation; regulations, including an update on new and emerging guidelines and on Global harmonization; technology updates; incurred sample stability; microdosing; dried blood spots and microsampling; challenges of 'free' and 'total' macromolecule quantification; stability issues in ligand binding assays or anomalous results. In excess of 450 delegates from more than 170 institutes and companies (industry, regulators and academia) from all global regions participated in the open and stimulating discussions. This manuscript provides an overview of the highlights discussed at the meeting.

Metabolite profiles of degarelix, a new gonadotropin-releasing hormone receptor antagonist, in rat, dog, and monkey.

Degarelix is a novel competitive gonadotropin-releasing hormone receptor blocker (antagonist). In this study, the nonclinical metabolism and excretion of degarelix was investigated in Sprague-Dawley rat, beagle dog, and cynomolgus monkey. Degarelix was found to be stable when incubated in microsomes and cryopreserved hepatocytes from animal liver tissue. Absorption, distribution, metabolism, and excretion studies in male rat, dog, and monkey showed that after a subcutaneous dose of tritium-labeled degarelix, the peptide was rapidly absorbed with C(max) in plasma of 1 to 2 h. The predominant route of excretion was via the kidneys and the bile. In rat and dog, most of the degarelix dose was eliminated within 48 h via urine and feces in equal amounts (40-50% in each matrix), whereas in monkey the major route of excretion was fecal (50%) and renal (22%). In plasma and urine samples from all three species, mainly intact degarelix was detected. In bile and feces samples from rats and dogs, the same truncated peptides of the parent decapeptide were detected. The major metabolites identified represented the N-terminal tetrapeptide, the pentapeptide, and the heptapeptide. From the animal studies, it could be concluded that degarelix is subject to common peptidic degradation in the liver and bile and is fully excreted via metabolic and biliary (as metabolites and parent compound) and urinary (mainly as parent compound) pathways. Systemic exposure to metabolic products seems to be low.

In vitro studies investigating the interactions between degarelix, a decapeptide gonadotropin-releasing hormone blocker, and cytochrome P450.

The decapeptide degarelix is a novel competitive gonadotropin-releasing hormone receptor antagonist that has been approved for the treatment of advanced prostate cancer by the FDA and the EU authorities. In this study, the interaction of degarelix with human cytochrome P450 (CYP450) enzymes was investigated in vitro. Inhibition of CYP450 was performed in human liver microsomes using documented marker substrates for the CYP450 isozymes CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP2E1. The inhibitory effects on selected P450 enzyme activities were investigated with degarelix concentrations representing the range of 2-200 times of expected clinical concentrations. No inhibition of any isozyme-catalysed biotransformations studied was detected. Induction of CYP450 enzyme activity by degarelix was investigated using primary human hepatocytes. Cryopreserved plateable hepatocytes and fresh hepatocytes in culture were treated for two-three consecutive days with degarelix at concentrations of 0.1, 1.0 and 10 µM. The cultured hepatocytes were also treated with three prototypical CYP450 inducers: omeprazole, phenobarbital and rifampin as positive controls for CYP450 enzyme induction. No induction of the activity of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19 and CYP3A4 isozymes was observed. Degarelix appears to be a poor substrate of the CYP450 enzyme system, and the in vitro results indicate that the interaction between CYP450 and degarelix is low. These results indicate that degarelix is unlikely to cause any clinically significant drug-drug interactions in vivo.

Pharmacokinetic interaction studies of atosiban with labetalol or betamethasone in healthy female volunteers.

OBJECTIVES: In two separate trials, we studied the concomitant administration of atosiban with labetalol and betamethasone to determine any possibility of a clinically relevant pharmacokinetic interaction. DESIGN: Study 1 was an open-label, single dose atosiban, multiple dose labetalol, interaction study. Study 2 was an open-label, randomised, three-period crossover pharmacokinetic study. SETTING: The studies were carried out at the Clinical Pharmacology Unit of AAI Deutschland GmbH & Co KG, Neu-Ulm, Germany. POPULATION: The study population consisted of healthy female volunteers. METHODS: In Study 1, 14 healthy female volunteers participated. On study day 1, a 12-hour intravenous infusion of 114.75 mg atosiban was administered; on days 2-4, participants received labetalol orally (100 mg twice daily), and on study day 5 they received the combined treatment. In Study 2, a total of 18 healthy female volunteers received, on three separate occasions, a 12-hour intravenous infusion of 114.75 mg atosiban, a single intramuscular injection of 12 mg betamethasone or the two drugs in combination. MAIN OUTCOME MEASURE: For Study 1, the outcome parameter for atosiban was area under the plasma concentration-time curve (AUC); the study parameters for labetalol were AUC, maximum plasma concentration (C(max)) and time to C(max) (t(max)). In Study 2, AUC, C(max) and time to C(max) (t(max)) were assessed for atosiban and betamethasone. RESULTS: Labetalol had no clinically relevant influence on the bioavailability (AUC) of atosiban. For labetalol, the co-administration with atosiban did not affect the extent of bioavailability, however, C(max) decreased by 36% and t(max) increased by 45 minutes. The C(min) was not affected by atosiban. The betamethasone and atosiban combination led to similar mean plasma concentration-time curves as the administration of each substance alone. Pharmacokinetic parameters (AUC, C(max), t(max)) did not differ markedly between treatments and all 90% CIs for ratios between treatments were fully within limits (80-125%). The co-administration of atosiban with labetalol or betamethasone resulted in similar tolerability to each substance alone. CONCLUSION: The co-administration of atosiban with betamethasone or labetalol had no clinically relevant influence on their bioavailability or tolerability.

Effect of growth hormone on hepatic cytochrome P450 activity in healthy elderly men.

OBJECTIVE: Our objective was to study the effect of recombinant human growth hormone (rhGH) on hepatic cytochrome P450 (CYP) activity in 30 healthy elderly men. METHODS: The study was carried out as a randomized, double-blind, placebo-controlled parallel-group study. rhGH or placebo was administered for a period of 12 weeks. CYP activity was measured before, after 12 weeks of rhGH and placebo administration, and at 4 weeks after termination of rhGH and placebo administration with use of the biomarker reactions of CYP1A2 (caffeine), CYP2C19 (mephenytoin), CYP2D6 (sparteine), CYP3A4 (endogenous cortisol metabolism), and antipyrine clearance as common markers of CYP activity. RESULTS: The metabolic ratio of caffeine increased significantly in the group that received growth hormone compared with placebo (median difference, 4.55; 95% confidence interval (CI), 1.64 to 8.60; versus -0.90; 95% CI, -5.70 to 1.36), indicating an induction of CYP1A2. Moreover, the S/R ratio of mephenytoin showed a small but significant increase (median difference, 0.02; 95% CI, 0 to 0.31; versus 0; 95% CI, -0.01 to 0.06), indicating an inhibition of CYP2C19. There were no significant changes of the metabolic ratios of cortisol and sparteine or the antipyrine clearance compared with placebo. CONCLUSIONS: These results indicate that growth hormone induces CYP1A2 and, to a lesser extent, inhibits CYP2C19 in elderly men, but it exerts no effects on CYP2D6 and CYP3A4. Although the induction of CYP1A2 may be of some clinical relevance, the small inhibition of CYP2C19 is probably unimportant.