Clinical Bridging Studies and Modeling Approach for Implementation of a Patient Centric Sampling Technique in Padsevonil Clinical Development.

Volumetric absorptive microsampling (VAMS) techniques have gained popularity these last years as innovative tool for collection of blood pharmacokinetic (PK) samples in clinical trials as they offer many advantages over dried blood spot and conventional venous blood sampling. The use of Mitra®, a blood collection device based on volumetric absorptive microsampling (VAMS) technology, was implemented during clinical development of padsevonil (PSL), an anti-seizure medication (ASM) candidate. The present study describes the approach used to bridge plasma (obtained from conventional venous blood sampling) and blood exposures (obtained with Mitra®) to support the use of Mitra as sole blood PK sampling method in clinical trials. Paired blood (using Mitra®) and plasma samples (using conventional venous blood sampling) were collected in healthy volunteers as well as in patients with epilepsy. PSL concentration in plasma and blood were analyzed using different approaches which included evaluation of blood-to-plasma ratios (B/P) over time, linear regression, Bland-Altman analysis as well as development of a linear-mixed effect model based on clinical pharmacology studies. Results showed that the observed in vivo B/P and the measured bias between the 2 collection methods were consistent with the measured in vitro B/P. Graphical analysis demonstrated a clear time effect on the B/P which was confirmed in the linear mixed effect model with sampling time identified as significant covariate. Finally, the built-in model was validated using independent datasets and was shown to adequately predict plasma concentration based on blood concentration with a mean bias of less than 9% (predicted versus observed plasma concentration).

Oral follicle-stimulating hormone agonist tested in healthy young women of reproductive age failed to demonstrate effect on follicular development but affected thyroid function.

OBJECTIVE: To assess the safety, pharmacokinetics, and pharmacodynamics of MK-8389. DESIGN: Double-blind, placebo-controlled, parallel-group, ascending dose study. SETTING: Two clinical research organizations. PATIENT(S): Healthy young women. INTERVENTION(S): Once-daily oral doses of MK-8389 or placebo for 14 days. MAIN OUTCOME MEASURE(S): Safety, including thyroid function tests (TFTs), pharmacokinetics, and follicular development (follicle size and number and serum E2 and inhibin B levels). RESULT(S): Treatment with MK-8389 was generally safe and well tolerated. An effect on TFTs was observed, which was transient and did not lead to clinical signs or symptoms but prevented dose escalation above 40 mg. MK-8389 was rapidly absorbed, slowly eliminated, and showed a large peak-to-trough ratio. No clinically meaningful effect was seen on follicle size and numbers, which was consistent with the low E2 levels. At doses >20 mg, inhibin B levels were increased, suggesting early follicular development at higher doses. CONCLUSION(S): Oral administration of MK-8389 demonstrated acceptable systemic exposure and was generally well tolerated. This study failed to demonstrate a clinically meaningful effect of MK-8389 on follicular development, whereas MK-8389 unexpectedly affected thyroid function. This study did not explore doses above 40 mg given the changes observed in TFTs, which may relate to high MK-8389 peak concentrations. CLINICAL TRIAL REGISTRATION NUMBER: EudraCT Number 2010-022396-57.

First evidence of ovulation induced by oral LH agonists in healthy female volunteers of reproductive age.

CONTEXT: Two new low-molecular-weight LH agonists (Org 43553 and Org 43902) were shown to induce ovulation in preclinical experiments. OBJECTIVE: Our objective was to assess the safety, pharmacokinetics, and pharmacodynamics of Org 43553 and Org 43902 when administered to healthy females. DESIGN AND SETTING: Org 43553 and 43902 studies were randomized, placebo-controlled, single-rising-dose first-in-human trials, which included 159 healthy female volunteers. Part 1 of the studies assessed the safety and pharmacokinetics. Part 2 evaluated the pharmacodynamics effect of a single oral dose of Org 43553 (25-900 mg) or Org 43902 (30-300 mg) to induce ovulation after the development of a large preovulatory follicle, whereas the endogenous LH surge was suppressed due to GnRH antagonist treatment while follicular development was supported with recombinant FSH. RESULTS: Org 43553 and 43902 were safe and well tolerated. Both compounds showed a fast absorption after oral intake, with peak concentrations reached within 0.5 to 1 hour. The elimination half-life of Org 43553 was 30 to 47 hours and that of Org 43902 was 17 to 22 hours. Ovulation induction confirmed by midluteal progesterone rise ≥15 nmol/L was proven in both studies, also when excluding subjects with an endogenous LH rise. The minimal effective dose for ovulation induction was 300 mg in both studies and resulted in an ovulation rate of 83% and 82%, respectively. CONCLUSIONS: These first proof-of-concept studies both demonstrated that a single oral intake of an low-molecular-weight LH agonist induces ovulation of the preovulatory follicle in pituitary-suppressed female volunteers of reproductive age.

The use of toxicokinetic data in preclinical safety assessment: a toxicologic pathologist perspective.

Collection of toxicokinetic data has become a routine practice during the last 15 years in most general toxicity studies on pharma. It enables the correlation of pathological changes with the plasma concentration of drugs and/or their metabolites. This overview summarizes the use of the toxicokinetic data from the perspective of the toxicologic pathologist.