Pharmacokinetics, safety, and tolerability of the novel tetrameric gadolinium-based MRI contrast agent gadoquatrane in healthy Chinese and Japanese men: Two randomized dose-escalation studies including concentration-QTc modeling.

PURPOSE: To investigate the pharmacokinetics, safety, and tolerability of the novel tetrameric high-relaxivity gadolinium-based contrast agent gadoquatrane in Japanese (Study 1) and Chinese men (Study 2). PARTICIPANTS AND METHODS: In two similarly designed single-center, randomized, single-blind, placebo-controlled, consecutive-cohort dose-escalation studies, healthy volunteers were randomly assigned to intravenous administration of gadoquatrane (0.01-0.1 mmol gadolinium/kg body weight) or placebo. Study procedures included blood sampling and collection of urine for pharmacokinetic analyses and safety assessments. RESULTS: Twenty-five healthy Japanese men (mean age ± standard deviation: 26±5.9 years) and 23 healthy Chinese men (31±7.6 years old) were evaluated. In both studies, the pharmacokinetic profile of gadoquatrane was characterized by rapid distribution of the drug into the extracellular space and fast renal elimination. Postdose gadolinium concentrations rapidly declined with a geometric mean effective half-life of 1.3-1.4 h. The exposure increased approximately dose-proportionally with dose. The body weight-normalized volume of distribution was constant across dose levels (0.21-0.24 L/kg). Total recovery of gadolinium in urine amounted to 82-95 % (Study 1) and 96-99 % (Study 2) of the dose administered. Only a few mild, transient adverse events were reported, none of which gave rise to any safety concerns. Exploratory drug concentration-QTc modeling indicated no risk of a clinically relevant QT/QTc prolongation at the anticipated diagnostic dose. CONCLUSION: Gadoquatrane was safe and well tolerated at all doses tested. The pharmacokinetic profile was essentially the same as that of other extracellular macrocyclic gadolinium-based contrast agents and was consequentially also similar for Japanese and Chinese participants.

Pharmacokinetics, Safety, and Tolerability of the Novel Tetrameric, High-Relaxivity, Macrocyclic Gadolinium-Based Contrast Agent Gadoquatrane in Healthy Adults.

OBJECTIVES: Gadolinium (Gd)-based contrast agents are well established in clinical routine and have been proven safe and effective. However, there is a need for "next-generation" Gd-based contrast agents that would allow lowering the Gd dose used for routine contrast-enhanced magnetic resonance imaging procedures. The objective of this first-in-human study was to investigate the pharmacokinetic profile, safety, and tolerability of gadoquatrane, a novel high-relaxivity Gd-based contrast agent. MATERIALS AND METHODS: This study was conducted in 2018/2019 as a prospective, randomized, single-blind, single-dose, placebo-controlled, escalating-dose study. Healthy volunteers were randomly assigned (6:2) to intravenous administration of gadoquatrane (0.025 to 0.2 mmol Gd/kg body weight) or placebo. Study procedures included collection of blood samples and excreta for pharmacokinetic analyses and safety assessments. RESULTS: Forty-nine healthy study participants (mean age ± SD, 35 ± 6.3 years; 24 female) were evaluated. The effective half-life of gadoquatrane in plasma was short and similar in all dose groups (1.4-1.7 hours). Plasma concentrations around the lower quantitation limit (0.0318 µmol Gd/L) were reached 15-72 hours after administration. The volume of distribution at steady state was ~0.2 L/kg in all dose groups. The clearance (total and renal) was ~0.1 L/h per kilogram in all groups. Across dose groups, the exposure of gadoquatrane increased dose-proportionally. Metabolite profiling revealed no hint of degradation in vivo or release of free Gd. Seven of 36 participants (19.4%) receiving gadoquatrane and 4 of 13 participants (30.8%) receiving placebo experienced mild or moderate treatment-emergent adverse events. No serious adverse events occurred. The analysis of the Gd concentration-QTc interval relationship indicated no risk of QT/QTc prolongation (>10 milliseconds) with gadoquatrane at clinical dose levels. CONCLUSIONS: Gadoquatrane with its high-relaxivity, pharmacokinetic similarity to established Gd-based contrast agents and high tolerability is a promising "next-generation" contrast agent for magnetic resonance imaging.

Development of an Intrauterine Device Releasing Both Indomethacin and Levonorgestrel During the First Months of Use: Pharmacokinetic Characterization in Healthy Women.

BACKGROUND: Post-placement menstrual bleeding pattern changes with intrauterine contraceptives (IUCs), including levonorgestrel-releasing intrauterine systems (LNG-IUS), can be a reason for avoidance or early discontinuation. Prostaglandins play an important role in menstrual bleeding and pain. The key drivers of prostaglandin synthesis are cyclooxygenase (COX) enzymes, which are inhibited by non-steroidal anti-inflammatory drugs. In this study, we report the findings from pharmacokinetic (PK) analyses undertaken with an LNG-IUS (LNG-IUS 8) modified with an additional reservoir containing indomethacin (IND). METHODS: The IND/LNG-IUS 8 is a proof-of-concept device studied in a phase II proof-of-concept/dose-finding study. IND/LNG-IUS 8 contains the same LNG content as the unmodified LNG-IUS 8 (13.5 mg) but was prepared with three different IND doses (low, 6.5 mg; middle, 12.5 mg; and high, 15.4 mg), resulting in different daily release rates. Overall, 174 healthy, premenopausal women were randomized to one of the four treatment arms (low-, middle-, high-dose IND/LNG-IUS 8 or LNG-IUS 8). Initial and residual IND and LNG content were collected and the amount of IND and LNG released in vivo over the period of use was calculated. A subset of 62 participants underwent dense blood sampling for PK analysis. Concentrations of IND and LNG in plasma were determined by validated liquid chromatography-tandem mass spectrometry methods and plotted over time. Descriptive statistics were calculated for plasma drug concentrations and PK parameters. RESULTS: High-dose IND/LNG-IUS 8 initially released much higher levels of IND than expected based on in vitro release data, followed by a steep decline, with the reservoir emptied by 4.5 months. Middle- and low-dose IND/LNG-IUS 8 demonstrated steady sustained release of IND over time, emptying after 7.4 and 8.4 months, respectively. Peak plasma concentrations of IND for low- and middle-dose IND/LNG-IUS 8 remained below the 20% maximal inhibitory concentration (IC20) values for COX enzymes. The average daily IND release rate in vivo was 49 µg/day for low-dose and 112 µg/day for middle-dose IND/LNG-IUS 8. The IND release rate profile and IND plasma concentrations in vitro both decreased steadily over time with low- and middle-dose IND/LNG-IUS 8. The LNG release rate profile was comparable for all IND/LNG-IUS 8 dose groups and LNG-IUS 8. CONCLUSION: This PK study demonstrates that two different drugs can be released at different rates from an IUS designed with two drug reservoirs. Inclusion of IND does not impact the LNG PK profile. Low- and middle-dose IND/LNG-IUS 8 were associated with a systemic IND exposure that should preclude the occurrence of adverse events typically observed after oral IND dosing. STUDY REGISTRATION: ClinicalTrials.gov identifier number: NCT03562624.

Comparative pharmacokinetic analysis of levonorgestrel-releasing intrauterine systems and levonorgestrel-containing contraceptives with oral or subdermal administration route.

OBJECTIVE: To compare systemic exposure to levonorgestrel (LNG) released from commercially available intrauterine systems (IUSs), a subdermal implant, and oral contraceptives. METHODS: An integrated population pharmacokinetic (popPK) analysis of data from over 3400 individuals in ten clinical studies with six different LNG-releasing contraceptives (four long-acting reversible contraceptives [LARCs: LNG-IUS 8, 12, and 20, initially releasing LNG 14, 17.5, and 20 µg/day, a subdermal implant initially releasing LNG 100 µg/day according to label]; progestin-only pill [POP: LNG 30 µg/day]; and combined oral contraceptive [COC] pill [LNG 100 µg/day and ethinylestradiol 20 µg/day]), was conducted to generate a popPK model. LNG release rates, and total and unbound serum/plasma LNG concentrations with LARCs were estimated over the indicated period of use; maximum (Cmax) and average (Cav) serum LNG concentrations were estimated at steady state for oral contraceptives. Influence of body weight on LNG PK was also investigated. RESULTS: Serum LNG concentration with LARCs increased with increasing daily LNG release rate, being lowest with LNG-IUS 8, higher with LNG-IUS 12 and LNG-IUS 20, and highest with the subdermal implant (1.7-2.1-times that with LNG-IUS 20). Compared with early serum LNG concentrations with LNG-IUS 20, Cav and Cmax were 1.7- and 4.5-fold higher with POP, and 8.6- and 18-fold higher with COC. Total LNG bioavailability was >97% for the LNG-IUSs and 66-80% with other contraceptives. Serum/plasma LNG concentrations decreased with increasing body weight. CONCLUSIONS: Among the contraceptives examined, COC had the highest and LNG-IUSs the lowest systemic exposure to LNG. Systemic LNG concentration was inversely correlated to body weight.