Dried Blood Spot Methodology in Combination With Liquid Chromatography/Tandem Mass Spectrometry Facilitates the Monitoring of Teriflunomide.

BACKGROUND: Teriflunomide, a once-daily oral immunomodulator approved for treatment of relapsing-remitting multiple sclerosis, is eliminated slowly from plasma. If necessary to rapidly lower plasma concentrations of teriflunomide, an accelerated elimination procedure using cholestyramine or activated charcoal may be used. The current bioanalytical assay for determination of plasma teriflunomide concentration requires laboratory facilities for blood centrifugation and plasma storage. An alternative method, with potential for greater convenience, is dried blood spot (DBS) methodology. Analytical and clinical validations are required to switch from plasma to DBS (finger-prick sampling) methodology. METHODS: Using blood samples from healthy subjects, an LC-MS/MS assay method for quantification of teriflunomide in DBS over a range of 0.01-10 mcg/mL was developed and validated for specificity, selectivity, accuracy, precision, reproducibility, and stability. Results were compared with those from the current plasma assay for determination of plasma teriflunomide concentration. RESULTS: Method was specific and selective relative to endogenous compounds, with process efficiency ∼88%, and no matrix effect. Inaccuracy and imprecision for intraday and interday analyses were <15% at all concentrations tested. Quantification of teriflunomide in DBS assay was not affected by blood deposit volume and punch position within spot, and hematocrit level had a limited but acceptable effect on measurement accuracy. Teriflunomide was stable for at least 4 months at room temperature, and for at least 24 hours at 37°C with and without 95% relative humidity, to cover sampling, drying, and shipment conditions in the field. The correlation between DBS and plasma concentrations (R = 0.97), with an average blood to plasma ratio of 0.59, was concentration independent and constant over time. CONCLUSIONS: DBS sampling is a simple and practical method for monitoring teriflunomide concentrations.

Contrasting Effects of Lixisenatide and Liraglutide on Postprandial Glycemic Control, Gastric Emptying, and Safety Parameters in Patients With Type 2 Diabetes on Optimized Insulin Glargine With or Without Metformin: A Randomized, Open-Label Trial.

OBJECTIVE: This mechanistic trial compared the pharmacodynamics and safety of lixisenatide and liraglutide in combination with optimized insulin glargine with/without metformin in type 2 diabetes (T2D). RESEARCH DESIGN AND METHODS: This was a multicenter, randomized, open-label, three-arm trial comparing lixisenatide 20 µg and liraglutide 1.2 and 1.8 mg once daily for 8 weeks in combination with insulin glargine after optimized titration. The primary end point was change from baseline to week 8 in incremental area under the postprandial plasma glucose curve for 4 h after a standardized solid breakfast (AUC PPG0030-0430 h). Changes from baseline in gastric emptying, 24-h plasma glucose profile, HbA1c, fasting plasma glucose (FPG), 24-h ambulatory heart rate and blood pressure, amylase and lipase levels, and adverse events (AEs) were also assessed. RESULTS: In total, 142 patients were randomized and treated. Lixisenatide 20 µg achieved greater reductions of AUC PPG0030-0430 h compared with liraglutide (marginal mean [95% one-sided CI] treatment difference, -6.0 [-7.8] h ⋅ mmol/L [-108.3 (-140.0) h ⋅ mg/dL] vs. liraglutide 1.2 mg and -4.6 [-6.3] h ⋅ mmol/L [-83.0 (-114.2) h ⋅ mg/dL] vs. liraglutide 1.8 mg; P < 0.001 for both), and gastric emptying was delayed to a greater extent than with liraglutide 1.2 and 1.8 mg (P < 0.001 for treatment comparisons). FPG was unchanged in all treatment arms. At week 8, mean ± SD HbA1c was 6.2 ± 0.4% (44 ± 5 mmol/mol), 6.1 ± 0.3% (44 ± 4 mmol/mol), and 6.1 ± 0.3% (44 ± 4 mmol/mol) for lixisenatide 20 µg and liraglutide 1.2 and 1.8 mg, respectively. At week 8, both liraglutide doses increased marginal mean ± SE 24-h heart rate from baseline by 9 ± 1 bpm vs. 3 ± 1 bpm with lixisenatide (P < 0.001). Occurrence of symptomatic hypoglycemia was higher with lixisenatide; gastrointestinal AEs were more common with liraglutide. Lipase levels were significantly increased from baseline with liraglutide 1.2 and 1.8 mg (marginal mean ± SE increase 21 ± 7 IU/L for both; P < 0.05). CONCLUSIONS: Lixisenatide and liraglutide improved glycemic control in optimized insulin glargine-treated T2D albeit with contrasting mechanisms of action and differing safety profiles.