Augmentation therapy with the approved dose of 60 mg/kg weekly intravenous (IV) alpha-1 proteinase inhibitor (alpha1-PI), achieves a trough serum level of 11 μM in individuals with alpha-1 antitrypsin deficiency (AATD), yet this is still below the level observed in healthy individuals. This study assessed the safety and pharmacokinetic profile of weekly infusions of a 120 mg/kg dose of alpha1-PI in 30 adults with AATD. Subjects with symptomatic, genetically determined (genotypes PI*ZZ, PI*Z(null), PI*(null)(null) or PI*(Z)Mmalton) AATD were randomly assigned to weekly infusions of 60 or 120 mg/kg alpha1-PI (Prolastin-C®) for 8 weeks before crossing over to the alternate dose for 8 weeks. Adverse events (AEs) (including exacerbations), vital signs, pulmonary function tests, and laboratory assessments were recorded. Pharmacokinetic measurements included AUC0-7days, Cmax, trough, tmax, and t1/2, based on serum alpha1-PI concentrations. In total for both treatments, 112 AEs were reported, with exacerbation of COPD being the most frequent, consistent with the subjects' diagnoses. Mean steady-state serum alpha1-PI concentrations following 120 mg/kg weekly IV alpha1-PI were higher than with the 60 mg/kg dose and mean trough concentrations were 27.7 versus 17.3 μM, respectively. Dose proportionality was demonstrated for AUC0-7days and Cmax, with low inter-subject variability. The 120 mg/kg alpha1-PI weekly dose was considered to be safe and well tolerated, and provided more favorable physiologic alpha1-PI serum levels than the currently recommended 60 mg/kg dose. The effect of this dosing regimen on slowing and/or preventing emphysema progression in subjects with AATD warrants further investigation.

BackgroundAlpha1-antitrypsin (AAT) deficiency is characterized by low blood levels of alpha1-proteinase inhibitor (alpha1-PI) and may lead to emphysema. Alpha1-PI protects pulmonary tissue from damage caused by the action of proteolytic enzymes. Augmentation therapy with Prolastin® (Alpha1-Proteinase Inhibitor [Human]) to increase the levels of alpha1-PI has been used to treat individuals with AAT deficiency for over 20 years. Modifications to the Prolastin manufacturing process, incorporating additional purification and pathogen-reduction steps, have led to the development of an alpha1-PI product, designated Prolastin®-C (Alpha1-Proteinase inhibitor [Human]). The pharmacokinetic comparability of Prolastin-C to Prolastin was assessed in subjects with AAT deficiency.MethodsIn total, 24 subjects were randomized to receive 60 mg/kg of functionally active Prolastin-C or Prolastin by weekly intravenous infusion for 8 weeks before crossover to the alternate treatment for another 8 weeks. Pharmacokinetic plasma samples were drawn over 7 days following last dose in the first treatment period and over 10 days following the last dose in the second period. The primary end point for pharmacokinetic comparability was area under the plasma concentration versus time curve over 7 days post dose (AUC0-7 days) of alpha1-PI determined by potency (functional activity) assay. The crossover phase was followed by an 8-week open-label treatment phase with Prolastin-C only.ResultsMean AUC0-7 days was 155.9 versus 152.4 mg*h/mL for Prolastin-C and Prolastin, respectively. The geometric least squares mean ratio of AUC0-7 days for Prolastin-C versus Prolastin had a point estimate of 1.03 and a 90% confidence interval of 0.97-1.09, demonstrating pharmacokinetic equivalence between the 2 products. Adverse events were similar for both treatments and occurred at a rate of 0.117 and 0.078 per infusion for Prolastin-C (double-blind treatment phase only) and Prolastin, respectively (p = 0.744). There were no treatment-emergent viral infections in any subject for human immunodeficiency virus, hepatitis B or C, or parvovirus B19 during the course of the study.ConclusionProlastin-C demonstrated pharmacokinetic equivalence and a comparable safety profile to Prolastin.Trial RegistrationClinicalTrials.gov Identifier: NCT00295061

Overall, there were no clinically significant differences in the relative bioavailability of oral treprostinil when administered immediately after meals containing 250-500 calories and 30-50% fat. These data support the administration of oral treprostinil with a meal containing as few as 250 calories and 30-50% fat, which is significant for ensuring patient convenience and compliance, particularly as consistency with regard to meals may impact oral treprostinil pharmacokinetics.

Three times daily dosing of 0.5 mg oral treprostinil for 7 days was well tolerated in healthy subjects and provided sustained plasma exposure throughout the day at steady state without drug accumulation. This study provides data to support further evaluation of TID dosing regimen of oral treprostinil.

This randomized, 4-way crossover study assessed the single-dose pharmacokinetics and relative bioavailability of naproxen and esomeprazole after administration of a fixed-dose combination tablet of enteric-coated (EC) naproxen 500 mg and non-EC esomeprazole magnesium 20 mg (NAP/ESO tablet). Equivalent doses of an EC naproxen tablet plus an EC esomeprazole magnesium capsule taken concomitantly, an EC naproxen tablet alone, or an EC esomeprazole magnesium capsule alone were used as comparators. Forty healthy adults were randomized to receive 4 study treatments with a washout interval ≥12 days. Naproxen plasma profiles were similar between the NAP/ESO tablet and EC naproxen, although median t(max) was longest for the NAP/ESO tablet (5.3 vs 3.5-4.0 hours). Naproxen C(max), AUC(0-∞), and AUC(0-t) showed bioequivalence between naproxen formulations. The NAP/ESO tablet produced much shorter esomeprazole t(max) than the EC esomeprazole formulation (0.45 vs 2.5 hours). Esomeprazole C(max) and AUCs were comparable between the EC esomeprazole formulation administered with or without EC naproxen but were lower with the NAP/ESO tablet. In conclusion, there are no pharmacokinetic drug interactions between naproxen and esomeprazole. The NAP/ESO tablet is bioequivalent to EC naproxen, and as expected, the bioavailability of non-EC esomeprazole from the NAP/ESO tablet is lower than the EC esomeprazole formulation.