Dysphagia for medication in Parkinson's disease.

Dysphagia is common in Parkinson's disease (PD) and is assumed to complicate medication intake. This study comprehensively investigates dysphagia for medication and its association with motor complications in PD. Based on a retrospective analysis, a two-dimensional and graduated classification of dysphagia for medication was introduced differentiating swallowing efficiency and swallowing safety. In a subsequent prospective study, sixty-six PD patients underwent flexible endoscopic evaluation of swallowing, which included the swallowing of 2 tablets and capsules of different sizes. Dysphagia for medication was present in nearly 70% of PD patients and predicted motor complications according to the MDS-UPDRS-part-IV in a linear regression model. Capsules tended to be swallowed more efficiently compared to tablets, irrespective of size. A score of ≥1 on the swallow-related-MDS-UPDRS-items can be considered an optimal cut-off to predict dysphagia for medication. Swallowing impairment for oral medication may predispose to motor complications.

The Effect of CYP3A Induction and Inhibition on the Pharmacokinetics of Laquinimod, a Novel Neuroimmunomodulator.

Laquinimod, a neuroimmunomodulator, is extensively metabolized by cytochrome P450 (CYP) 3A4, and modulations of CYP3A4 activity may lead to alterations in the pharmacokinetics and/or clinical effects of laquinimod. To determine the drug-drug interaction potential of laquinimod with CYP3A inhibitors and inducers, interaction assessments were conducted in healthy volunteers using single-dose administration of laquinimod before and after multiple dosing of CYP3A inhibitors (ketoconazole, fluconazole, and cimetidine) or a CYP3A4 inducer (rifampin). For ketoconazole, subjects (n = 14) received laquinimod 0.6 mg following 1 day of ketoconazole (400 mg daily) pretreatment, a single concomitant dose, and 28 additional days. For fluconazole, subjects (n = 14) received laquinimod 0.6 mg after a single fluconazole dose of 400 mg followed by 200-mg daily fluconazole administration for 20 additional days. For cimetidine, subjects (n = 14) received laquinimod 0.6 mg following 1 day of cimetidine (800 mg twice daily) pretreatment, a single concomitant dose, and 21 additional days. For rifampin, subjects (n = 14) received laquinimod 0.6 mg following 9 days of rifampin (600 mg daily) pretreatment, a single concomitant dose, and 12 additional days. Coadministration of laquinimod with CYP3A inhibitors, ketoconazole, fluconazole, and cimetidine increased laquinimod area under the plasma concentration-time curve from time zero to infinity by approximately 3.1-, 2.5-, and 1.1-fold, respectively. Coadministration of laquinimod with rifampin decreased laquinimod area under the plasma concentration-time curve from time zero to infinity by 5-fold. These results indicate that coadministration of laquinimod with moderate to strong inhibitors of CYP3A or strong inducers of CYP3A may give rise to significant pharmacokinetic drug interactions.

A Thorough QT/QTc Study With Laquinimod, a Novel Immunomodulator in Development for Multiple Sclerosis and Huntington Disease.

In this randomized double-blind study, 4 groups of healthy subjects (50 per arm) participated to evaluate the effect of laquinimod, an oral treatment in development for multiple sclerosis and Huntington disease, on the QTc interval. Subjects received a dose of either 0.6 or 1.2 mg/day laquinimod for 14 days, placebo for 14 days, or 13 days of placebo followed by a dose of 400 mg moxifloxacin on day 14. Continuous 12-lead electrocardiograms were recorded on day -1 (baseline) and days 14 to 17,  and quadruplicate electrocardiograms were extracted at predefined time points. The primary measure was time-matched change from baseline in individual QTc (QTcI), and an analysis of variance was conducted on the placebo-corrected change from baseline data (ddQTcI). Pharmacokinetic-pharmacodynamic and safety assessments were included. Results showed that the upper limits of the 2-sided 90%CI for ddQTcI for both laquinimod doses were below 10 millisconds at all time points, whereas lower limits for moxifloxacin were above 5 milliseconds. No notable changes in ECG parameters were observed. Pharmacokinetic/pharmacodynamic analysis showed no positive correlation between laquinimod plasma levels and QTcI. In conclusion, laquinimod was not found to affect cardiac repolarization or to cause prolongation of QTcI at doses of 0.6 and 1.2 mg/day.

The effect of laquinimod, a novel immuno-modulator in development to treat Huntington disease, on the pharmacokinetics of ethinylestradiol and levonorgestrel in healthy young women.

PURPOSE: Laquinimod is an orally dosed immuno-modulator currently under development for Huntington's disease (HD). Preclinical findings suggest potential teratogenicity of laquinimod, thus the reproductive ability of females with HD treated with laquinimod needs to be closely managed. Because combined oral contraceptives (COC) are often used in this context, the pharmacokinetics of COC containing ethinylestradiol (EE) and levonorgestrel (LNG) in combination with laquinimod (0.6 mg/day) was evaluated. METHODS: In this randomized, phase-1 single-center, double-blind, placebo-controlled, 2-way crossover drug-drug interaction (DDI) study in 48 healthy premenopausal women, COC were administered in a 28-day regimen of 21 days followed by 7 pill-free days for 4 cycles and laquinimod or placebo was administered for 28 days in cycle 1 and cycle 3 starting 7 days prior to COC administration. Blood samples for pharmacokinetic profiling of laquinimod, EE and LNG were collected on day 21 and day 22 of Cycles 1 and 3 pre-dose and multiple times post-dose. RESULTS: The ratio of geometric means and 90% confidence intervals for AUC0-24 and Cmax of EE and LNG with and without laquinimod were all within the bioequivalence range (80 to 125%). Laquinimod pharmacokinetics was consistent with those observed in previous studies. The adverse event profile was in line with the current knowledge on the safety profile of both drugs, with headache as the most frequently reported treatment-related adverse event. CONCLUSION: The combination of COC and laquinimod treatment was found to be safe, tolerable, and devoid of any noticeable pharmacokinetic interaction.

Safety and in vivo immune assessment of escalating doses of oral laquinimod in patients with RRMS.

BACKGROUND: Laquinimod is an oral immunomodulator in clinical development to treat relapsing-remitting multiple sclerosis (RRMS). Laquinimod is in clinical development for the treatment of multiple sclerosis and Huntington Disease (HD). The objective of this study is to assess the safety, tolerability, pharmacokinetics (PK) and cytoimmunologic effects following escalating doses of laquinimod in patients with RRMS. METHODS: One hundred twelve patients were randomly assigned to laquinimod/placebo in a series of separate dose-escalating cohorts starting from a daily oral dose of 0.9 mg/1.2 mg escalating to 2.7 mg, in 0.3 mg increments. RESULTS: Twenty-eight patients received placebo and 84 received laquinimod ranging from 0.9 to 2.7 mg. No deaths occurred. One serious adverse event (SAE) of perichondritis was reported, which was unrelated to laquinimod (0.9 mg). There was no increased incidence of adverse events (AEs) with escalating doses. Laquinimod-treated patients showed more abnormal laboratory levels in liver enzymes, P-amylase, C-reactive protein (CRP), and fibrinogen, but most shifts were clinically non-significant. The exposure of laquinimod was dose proportional and linear in the tested dose range. An immunological substudy showed significant dose-dependent decreases in 6-sulpho LacNAc + dendritic cell (slanDC) frequency following laquinimod compared to placebo. CONCLUSION: Laquinimod doses up to 2.7 mg were safely administered to patients with RRMS. An in vivo effect of laquinimod on the innate immune system was demonstrated. TRIAL REGISTRATION: EudraCT Number: 2009-011234-99 . Registered 23 June 2009.

A comparative study of the effect of carbamazepine and valproic acid on the pharmacokinetics and metabolic profile of topiramate at steady state in patients with epilepsy.

PURPOSE: To compare the influence of enzyme-inducing comedication and valproic acid (VPA) on topiramate (TPM) pharmacokinetics and metabolism at steady state. METHODS: Three groups were assessed: (a) patients receiving TPM mostly alone (control group, n =13); (b) patients receiving TPM with carbamazepine (CBZ; n = 13); and (c) patients receiving TPM with VPA (n = 12). TPM and its metabolites were assayed in plasma and urine by liquid chromatography-mass spectrometry (LC-MS). RESULTS: No significant differences were found in TPM oral (CL/F) and renal (CL(r)) clearance between the VPA group and the control group. Mean TPM CL/F and CL(r) were higher in the CBZ group than in controls (2.1 vs. 1.2 L/h and 1.1 vs. 0.6L/h, respectively; p < 0.05). In all groups, the urinary recovery of unchanged TPM was extensive and accounted for 42-52% of the dose (p > 0.05). Urinary recovery of 2,3-O-des-isopropylidene-TPM (2,3-diol-TPM) accounted for 3.5% of the dose in controls, 2.2% in the VPA group (p > 0.05), and 13% in the CBZ group (p < 0.05). The recovery of 10-hydroxy-TPM (10-OH-TPM) was twofold higher in the CBZ group than in controls, but it accounted for only <2% of the dose. The plasma concentrations of TPM metabolites were severalfold lower than those of the parent drug. CONCLUSIONS: Renal excretion remains a major route of TPM elimination, even in the presence of enzyme induction. The twofold increase in TPM-CL/F in patients taking CBZ can be ascribed, at least in part, to stimulation of the oxidative pathways leading to formation of 2,3-diol-TPM and 10-OH-TPM. VPA was not found to have any clinically significant influence on TPM pharmacokinetic and metabolic profiles.