Novel aldo-keto reductase 1C3 inhibitor affects androgen metabolism but not ovarian function in healthy women: a phase 1 study.

OBJECTIVE: Aldo-keto reductase 1C3 (AKR1C3) has been postulated to be involved in androgen, progesterone, and estrogen metabolism. Aldo-keto reductase 1C3 inhibition has been proposed for treatment of endometriosis and polycystic ovary syndrome. Clinical biomarkers of target engagement, which can greatly facilitate drug development, have not yet been described for AKR1C3 inhibitors. Here, we analyzed pharmacodynamic data from a phase 1 study with a new selective AKR1C3 inhibitor, BAY1128688, to identify response biomarkers and assess effects on ovarian function. DESIGN: In a multiple-ascending-dose placebo-controlled study, 33 postmenopausal women received BAY1128688 (3, 30, or 90 mg once daily or 60 mg twice daily) or placebo for 14 days. Eighteen premenopausal women received 60 mg BAY1128688 once or twice daily for 28 days. METHODS: We measured 17 serum steroids by liquid chromatography-tandem mass spectrometry, alongside analysis of pharmacokinetics, menstrual cyclicity, and safety parameters. RESULTS: In both study populations, we observed substantial, dose-dependent increases in circulating concentrations of the inactive androgen metabolite androsterone and minor increases in circulating etiocholanolone and dihydrotestosterone concentrations. In premenopausal women, androsterone concentrations increased 2.95-fold on average (95% confidence interval: 0.35-3.55) during once- or twice-daily treatment. Note, no concomitant changes in serum 17ß-estradiol and progesterone were observed, and menstrual cyclicity and ovarian function were not altered by the treatment. CONCLUSIONS: Serum androsterone was identified as a robust response biomarker for AKR1C3 inhibitor treatment in women. Aldo-keto reductase 1C3 inhibitor administration for 4 weeks did not affect ovarian function.ClinicalTrials.gov Identifier: NCT02434640; EudraCT Number: 2014-005298-36.

Quantitative Assessment of Levonorgestrel Binding Partner Interplay and Drug-Drug Interactions Using Physiologically Based Pharmacokinetic Modeling.

Levonorgestrel (LNG) is the active moiety in many hormonal contraceptive formulations. It is typically coformulated with ethinyl estradiol (EE) to decrease intermenstrual bleeding. Due to its widespread use and CYP3A4-mediated metabolism, there is concern regarding drug-drug interactions (DDIs), particularly a suboptimal LNG exposure when co-administered with CYP3A4 inducers, potentially leading to unintended pregnancies. The goal of this analysis was to determine the impact of DDIs on the systemic exposure of LNG. To this end, we developed and verified a physiologically-based pharmacokinetic (PBPK) model for LNG in PK-Sim (version 8.0) accounting for the impact of EE and body mass index (BMI) on LNG's binding to sex-hormone binding globulin. Model parameters were optimized following intravenous and oral administration of 0.09 mg LNG. The combined LNG-EE PBPK model was verified regarding CYP3A4-mediated interaction by comparing to published clinical DDI study data with carbamazepine, rifampicin, and efavirenz (CYP3A4 inducers). Once verified, the model was applied to predict systemic LNG exposure in normal BMI and obese women (BMI ≥ 30 kg/m2 ) with and without co-administration of itraconazole (competitive CYP3A4 inhibitor) and clarithromycin (mechanism-based CYP3A4 inhibitor). Total and free LNG exposures, when co-administered with EE, decreased 2-fold in the presence of rifampin, whereas they increased 1.5-fold in the presence of itraconazole. Although changes in total and unbound exposure were decreased in obese women compared with normal BMI women, the relative impact of DDIs on LNG exposure was similar between both groups.

The Effects of Weak and Strong CYP3A Induction by Rifampicin on the Pharmacokinetics of Five Progestins and Ethinylestradiol Compared to Midazolam.

It is known that co-administration of CYP3A inducers may decrease the effectiveness of oral contraceptives containing progestins as mono-preparations or combined with ethinylestradiol. In a randomized clinical drug-drug interaction study, we investigated the effects of CYP3A induction on the pharmacokinetics of commonly used progestins and ethinylestradiol. Rifampicin was used to induce CYP3A. The progestins chosen as victim drugs were levonorgestrel, norethindrone, desogestrel, and dienogest as mono-products, and drospirenone combined with ethinylestradiol. Postmenopausal women (n = 12-14 per treatment group) received, in fixed sequence, a single dose of the victim drug plus midazolam without rifampicin, with rifampicin 10 mg/day (weak induction), and with rifampicin 600 mg/day (strong induction). The effects on progestin exposure were compared with the effects on midazolam exposure (as a benchmark). Unbound concentrations were evaluated for drugs binding to sex hormone binding globulin. Weak CYP3A induction, as confirmed by a mean decrease in midazolam exposure by 46%, resulted in minor changes in progestin exposure (mean decreases: 15-37%). Strong CYP3A induction, in contrast, resulted in mean decreases by 57-90% (mean decrease in midazolam exposure: 86%). Namely, the magnitude of the observed induction effects varied from weak to strong. Our data might provide an impetus to revisit the currently applied clinical recommendations for oral contraceptives, especially for levonorgestrel and norethindrone-containing products, and they might give an indication as to which progestin could be used, if requested, by women taking weak CYP3A inducers-although it is acknowledged that the exact exposure-response relationship for contraceptive efficacy is currently unclear for most progestins.

Pharmacokinetic interaction between the CYP3A4 inhibitor ketoconazole and the hormone drospirenone in combination with ethinylestradiol or estradiol.

AIMS: The present study was conducted to investigate the influence of the strong CYP3A4 inhibitor ketoconazole (KTZ) on the pharmacokinetics of drospirenone (DRSP) administered in combination with ethinylestradiol (EE) or estradiol (E2). METHODS: This was a randomized, multicentre, open label, one way crossover, fixed sequence study with two parallel treatment arms. A group sequential design allowed terminating the study for futility after first study cohort. About 50 healthy young women were randomized 1 : 1 to 'DRSP/EE' or 'DRSP/E2'. Subjects in the 'DRSP/EE' group received DRSP 3 mg/EE 0.02 mg (YAZ®, Bayer) once daily for 21 to 28 days followed by DRSP 3 mg/EE 0.02 mg once daily plus KTZ 200 mg twice daily for 10 days. Subjects in the 'DRSP/E2' group received DRSP 3 mg/E2 1.5 mg (research combination) once daily for 21 to 28 days followed by DRSP 3 mg/E2 1.5 mg once daily plus KTZ 200 mg twice daily for 10 days. RESULTS: Oral co-administration of DRSP/EE or DRSP/E2 and KTZ resulted in an increase in DRSP exposure (AUC(0,24 h)) in both treatment groups: DRSP/EE group: 2.68-fold DRSP increase (90% CI 2.44, 2.95); DRSP/E2 group: 2.30-fold DRSP increase (90% CI 2.08, 2.54). EE and estrone (metabolite of E2) exposures were increased ~1.4-fold whereas E2 exposure was largely unaffected by KTZ co-administration. CONCLUSIONS: A moderate pharmacokinetic drug-drug interaction between DRSP and KTZ was demonstrated in this study. No relevant changes of medical concern were detected in the safety data collected in this study.

Bioequivalence evaluation of a folate-supplemented oral contraceptive containing ethinylestradiol/drospirenone/levomefolate calcium versus ethinylestradiol/drospirenone and levomefolate calcium alone.

BACKGROUND: Neural tube defects (NTDs) are congenital malformations that occur during early embryonic development. Suboptimal maternal folate status is a well-known risk factor for the occurrence of NTDs, and periconceptional folic acid supplementation has been shown to reduce the risk of NTDs. Folate-supplemented oral contraceptives (OCs) offer a means of improving folate status in women of childbearing potential by increasing their likelihood of having raised folate levels at the time of conception. OBJECTIVE: This study aimed to demonstrate bioequivalence of ethinylestradiol (EE), drospirenone and L-5-methyl-tetrahydrofolate (L-5-methyl-THF; active moiety of levomefolate calcium) when taken as a new folate-supplemented OC containing EE/drospirenone/levomefolate calcium, with the respective OC containing EE/drospirenone and a tablet containing levomefolate calcium only. METHODS: This was a randomized, open-label, three-period crossover study carried out at a single centre in Germany. The study included 45 healthy women (age range 18-38 years). The women were randomly assigned to single doses of (i) EE 0.03 mg/drospirenone 3 mg/levomefolate calcium 0.451 mg (SAFYRAL®), (ii) EE 0.03 mg/drospirenone 3 mg (Yasmin®), and (iii) levomefolate calcium 0.451 mg, administered using a crossover design, with one or more menstrual cycle washout between doses. The primary variables were maximum concentrations (C(max)) and area under the concentration versus time curve (AUC) values for EE, drospirenone and L-5-methyl-THF. RESULTS: The bioavailability of EE and drospirenone was similar after administration of EE/drospirenone/levomefolate calcium and EE/drospirenone. The geometric mean ratios (GMRs) and its 90% confidence intervals (CIs) for AUC values and C(max) were within the pre-specified range (80.00-125.00%) for bioequivalence for EE and drospirenone in both formulations. The bioavailability of L-5-methyl-THF was similar after administration of EE/drospirenone/levomefolate calcium and levomefolate calcium. The respective GMRs and 90% CIs of baseline-uncorrected and -corrected AUC(last) (AUC from time zero to time of last measurable concentration) and C(max) were also within the 80.00-125.00% range. CONCLUSION: The novel folate-supplemented OC EE/drospirenone/levomefolate calcium is bioequivalent to the established OC Yasmin® (EE/drospirenone components) and to levomefolate calcium (folate component).

Assessment of QT(c)-prolonging potential of BX471 in healthy volunteers. A 'thorough QT study' following ICH E14 using various QT(c) correction methods.

AIMS: Within the framework of the clinical development of BX471, this study was intended to provide experience in conducting 'thorough QT(c) studies' according to ICH E14. A broad range of QT correction methods and analysis strategies was employed. METHODS A double-blind, placebo- and positive-controlled, single-centre, three-way cross-over study was conducted in 74 healthy volunteers. Electrocardiograms were read by blinded experts. QT correction methods included Bazett's (QT(c)B), Fridericia's (QT(c)F) and several regression-based corrections. RESULTS: There was a significant QT(c)F prolongation of 10.26 ms by the positive control compared with placebo [95% confidence interval (7.83, 12.70)]. BX471 at therapeutic doses did not cause substantial QT(c) prolongation [QT(c)F estimate 2.93 ms, 95% confidence interval (1.00, 4.86); QT(c)B estimate 3.30 ms, 95% confidence interval (0.85, 5.74)]. Regression-based QT correction methods yielded similar results to Fridericia's correction [e.g. using a linear regression across the study population, QT(c) estimate 2.39 ms, 95% confidence interval (0.55, 4.23)]. Differences between the various regression-based correction methods were small. Results were not affected by whether the QT corrections were performed per ECG or per beat. CONCLUSIONS: BX471 does not cause meaningful QT(c) prolongation. Three QT correction methods may be sufficient in future studies: Bazett's (required by regulatory authorities), Fridericia's (as the most reliable fixed formula) and a regression-based correction (individually or population-based), each performed per ECG (i.e. applied to the means of several beats of one ECG recording).

A phase I dose escalation study of the pharmacokinetics and tolerability of ZK 304709, an oral multi-targeted growth inhibitor (MTGI), in patients with advanced solid tumours.

PURPOSE: The toxicities, pharmacokinetics and recommended dose of oral once daily ZK 304709, a novel multi-targeted growth inhibitor (MTGI) with activity against cell-cycle progression and angiogenesis, was investigated in patients by administration for 14 consecutive days followed by 14 days recovery. METHODS: Patients with solid tumours resistant to standard treatments were enrolled in an accelerated titration design. RESULTS: Thirty-seven patients received ZK 304709 from 15 to 285 mg daily. The most common drug-related adverse events were vomiting, diarrhoea and fatigue. Systemic exposure to ZK 304709 increased with dose up to 90 mg daily but plateaued thereafter, with high inter-individual variability at all doses. Thirteen patients had stable disease as best response as per RECIST criteria. CONCLUSIONS: There was no increase in exposure to ZK 304709 with dose escalation above 90 mg, and the MTD was not determined. This study illustrates the importance of phase I pharmacokinetic data to guide dose escalation and drug development.

Open-label, non-randomised, inter-individual dose escalation of ZK 304709 with the evaluation of safety, tolerability, pharmacokinetics, oral bioavailability and orientating efficacy after daily administration in patients with advanced cancer (7 d treatment and 14 d recovery).

PURPOSE: The primary objectives of this study were to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of ZK 304709, a novel multi-targeted growth inhibitor (MTGI(trade mark)), in man. Secondary end-points included safety evaluation, tolerability, pharmacokinetic profiling and assessment of response using standard and novel surrogate pharmacodynamic end-points. MATERIALS AND METHODS: Patients (n=40) with advanced solid malignancies were treated with ZK 304709, administered orally once daily for 7 d with 14 d recovery. Doses were escalated in sequential cohorts of three patients with expansion to 6-7 patients should a dose-limiting toxicity occur. RESULTS: ZK 304709 was safely administered up to 360mg. However, above 90mg blood concentrations increased only slightly. As this dose was not deemed likely to result in meaningful pharmacologic or clinical activity, the trial was stopped before the MTD was ascertained. It was therefore not possible to make a reliable assessment of efficacy or pharmacodynamic end-points. CONCLUSIONS: Due to the lack of further increment in blood concentrations above a dose of 90mg, which was felt from previous animal studies to be unlikely to result in meaningful pharmacologic or clinical activity, this study was stopped early.