Population Pharmacokinetic Analysis of BMS-986166, a Novel Selective Sphingosine-1-Phosphate-1 Receptor Modulator, and Exposure-Response Assessment of Lymphocyte Counts and Heart Rate in Healthy Participants.

Sphingosine-1-phosphate (S1P) binding to the S1P-1 receptor (S1P1R) controls the egress of lymphocytes from lymphoid organs and targets modulation of immune responses in autoimmune diseases. Pharmacologic modulation of S1P receptors has been linked to heart rate reduction. BMS-986166, a prodrug of the active phosphorylated metabolite BMS-986166-P, presents an improved cardiac safety profile in preclinical studies compared to other S1P1R modulators. The pharmacokinetics, safety, and pharmacodynamics of BMS-986166 versus placebo after single (0.75-5.0 mg) and repeated (0.25-1.5 mg/day) oral administration were assessed in healthy participants after a 1-day lead-in placebo period. A population model was developed to jointly describe BMS-986166 and BMS-986166-P pharmacokinetics and predict individual exposures. Inhibitory sigmoid models described the relationships between average daily BMS-986166-P concentrations and nadir of time-matched (day -1) placebo-corrected heart rate on day 1 (nDDHR, where DD represents ∆∆) and nadir of absolute lymphocyte count (nALC). Predicted decreases in nDDHR and nALC were 9 bpm and 20% following placebo, with maximum decreases of 10 bpm in nDDHR due to drug effect, and approximately 80% in nALC due to drug and placebo. A 0.5-mg/day dose regimen achieves the target 65% reduction in nALC associated with a 2-bpm decrease in nDDHR over placebo.

Vascular Toxicity Risk Assessment of MC18 and MC70, Novel Potential Diagnostic Tools for In Vivo PET Studies.

The P-glicoprotein (P-gp) inhibitor MC18 has been recently proposed as a valuable PET tracer to measure P-gp expression in vivo. The aim of this study was to evaluate the toxic hazard towards the vasculature of MC18 along with the structurally related and more potent P-gp inhibitor MC70. Their effects on A7r5 and EA.hy926 cells viability, on the mechanical activity of fresh and cultured rat aorta rings as well as on Cav 1.2 channel current (ICa1.2 ) of A7r5 cells were studied. At concentrations >10 µM, MC18 and MC70 decreased cell viability causing evident morphological changes. In fresh rat aorta rings, both compounds (0.1-100 µM) antagonized phenylephrine-induced contraction in a concentration-dependent manner, with IC50 values in the range of 1.67-14.49 µM, whereas only MC18 caused a concentration-dependent decrease of the 60 mM K+ (K60)-induced responses. In rings cultured for 7 days with both compounds (1-10 µM), 10 µM MC70 significantly reduced, while 10 µM MC18 completely prevented the contractile response to both phenylephrine and K60. MC18 and MC70 (0.1-100 µM) inhibited ICa1.2 in a concentration-dependent manner with IC50 values of 16.81 and 32.13 µM, respectively. These findings demonstrate that MC18-induced vascular effects took place at concentrations that are at least three orders of magnitude higher than those (≤10 nM) allowing in vivo measurement of P-gp expression. Thus, MC18, and possibly MC70, can be considered promising PET tools for in vivo P-gp quantification.

Rotigotine transdermal system for the treatment of Parkinson's disease.

BACKGROUND: Levodopa has been the cornerstone of the treatment of Parkinson's disease (PD) for >30 years, but long-term levodopa therapy is associated with development of such motor complications as motor fluctuations, dyskinesias, and drug-induced involuntary movements. Rotigotine is a dopamine agonist with high affinity for the D(2) receptor. Rotigotine transdermal system, the first such system approved by the US Food and Drug Administration for the management of PD, has been formulated to deliver a consistent concentration of drug to the bloodstream with the goal of minimizing the complications associated with pulsatile dosing. OBJECTIVE: This article reviews the clinical pharmacology, pharmacokinetic and pharmacodynamic properties, tolerability, and efficacy of rotigotine transdermal system in the treatment of PD. METHODS: MEDLINE (1966-April 2008) and International Pharmaceutical Abstracts (1971-April 2008) were searched using the term rotigotine. All prospective, randomized clinical efficacy trials in humans were included. The reference lists of the identified articles were reviewed for additional publications. RESULTS: In clinical trials, rotigotine transdermal system at doses ranging from 4.5 to 67 mg/d was associated with significant clinical benefit in patients with early and advanced PD. In 4 randomized, doubleblind, placebo-controlled trials of 6 months' duration, patients receiving rotigotine transdermal system had significant improvements on the Unified Parkinson's Disease Rating Scale (UPDRS) part II (activities of daily living) that ranged from -0.3 to -4.2, compared with +0.92 to -2 for placebo (P < 0.001, rotigotine transdermal system vs placebo). In one trial that included pramipexole as an active comparator, the change in UPDRS II at 6 months was -4.2 in the rotigotine transdermal system group and -4.6 in the pramipexole group (P = NS, rotigotine transdermal system vs pramipexole). Changes on the UPDRS III (motor examination) at 6 months ranged from -3.58 to -8.7 with rotigotine transdermal system, compared with +0.38 to -4.3 in the placebo group and -10.3 in the pramipexole group (P < 0.001 vs placebo; P = NS vs pramipexole). The change in "off" time at 6 months ranged from -2.1 to -2.7 hours with rotigotine transdermal system, compared with -0.9 hour with placebo and -2.8 hours with pramipexole (P < 0.001 vs placebo; P = NS vs pramipexole). The proportion of patients achieving a >30% reduction in "off" time ranged from 55.1% to 59.7% of patients receiving rotigotine transdermal system, compared with 34.5% to 35.0% of patients receiving placebo and 67.0% of patients receiving pramipexole (P<0.001 vs placebo; P = NS vs pramipexole). The most commonly reported adverse event was application-site reaction, occurring in 9% to 46% of patients receiving rotigotine transdermal system, compared with 5% to 13% of patients receiving placebo. Other adverse events occurring in >20% of patients receiving rotigotine transdermal system were somnolence(8%\2-33%)and nausea(12%-49%). Less than 5% of patients assigned to rotigotine transdermal system discontinued study medication because of an adverse drug event. CONCLUSIONS: The available evidence suggests that rotigotine transdermal system was effective compared with placebo in decreasing morbidity in patients with early and advanced PD. The most commonly reported adverse events associated with rotigotine transdermal system were application-site reaction, nausea, and somnolence. Additional clinical trials are needed to determine the long-term tolerability profile of rotigotine transdermal system and its clinical efficacy and tolerability compared with oral dopamine agonists.