Marjie L. Hard

Relative bioavailability and safety of aripiprazole lauroxil, a novel once-monthly, long-acting injectable atypical antipsychotic, following deltoid and gluteal administration in adult subjects with schizophrenia.

Aripiprazole lauroxil is a linker lipid ester of aripiprazole for extended-release intramuscular (IM) injection. This multicenter, randomized, open-label study evaluated the pharmacokinetics (PK), relative bioavailability, and tolerability of a single IM deltoid or gluteal injection of aripiprazole lauroxil in adult subjects with chronic stable schizophrenia or schizoaffective disorder. Forty-six subjects were randomized 1:1 to aripiprazole lauroxil 441 mg IM in the deltoid or gluteal muscle. Samples were collected through 89 days post-dose to measure levels of aripiprazole lauroxil, N-hydroxymethyl aripiprazole, aripiprazole, and dehydro-aripiprazole. Forty-three (93.5%) subjects completed all study assessments; most were CYP2D6 extensive or immediate metabolizers (96%); two (4%) were poor metabolizers. The PK of aripiprazole following aripiprazole lauroxil was characterized by a steady rise in plasma concentrations (Tmax 44-50 days), a broad peak, and prolonged exposure attributable to the dissolution of aripiprazole lauroxil and formation rate-limited elimination of aripiprazole (t1/2=15.4-19.2 days). Deltoid vs. gluteal administration resulted in slightly higher Cmax aripiprazole concentrations [1.31 (1.02, 1.67); GMR 90% CI]; total exposure (AUCinf) was similar between sites of administration [0.84 (0.57, 1.24)]. N-hydroxymethyl-aripiprazole and dehydro-aripiprazole exposures were 10% and 33-36%, respectively, of aripiprazole exposure following aripiprazole lauroxil. The most common adverse events were injection site pain in 20 subjects (43.5%) and headache in 6 subjects (13.0%) of mild intensity occurring at a similar rate with deltoid and gluteal administration. Exposure ranges with deltoid and gluteal administration overlapped, suggesting that these sites may be used interchangeably. Despite a higher incidence of adverse events, deltoid muscle provides a more accessible injection site and could facilitate patient acceptance.

Aripiprazole Lauroxil: Pharmacokinetic Profile of This Long-Acting Injectable Antipsychotic in Persons With Schizophrenia

Background Aripiprazole lauroxil is an extended-release prodrug of aripiprazole for intramuscular injection, approved for schizophrenia treatment. We developed a population pharmacokinetic (PopPK) model to characterize aripiprazole lauroxil PK and evaluate dosing scenarios likely to be encountered in clinical practice. Methods Data from 616 patients with schizophrenia, collected from 5 clinical studies, were used to construct the PopPK model. The model was subsequently used to evaluate various dose levels and frequency and the impact of dosing delay on aripiprazole concentrations. Findings The results of the model indicate that aripiprazole is released into the systemic circulation after 5 to 6 days, and release continues for an additional 36 days. The slow increase in aripiprazole concentration after injection necessitates the coadministration of oral aripiprazole for 21 days with the first injection. Based on the PopPK model simulations, a dosing interval of 882 mg every 6 weeks results in aripiprazole concentrations that fall within the concentration range associated with the efficacious aripiprazole lauroxil dose range (441–882 mg dosed monthly). A 662-mg monthly dose also resulted in aripiprazole concentrations within the efficacious dose range. Aripiprazole lauroxil administration results in prolonged exposure, such that dose delays of 2 to 4 weeks, depending on the dose regimen, do not require oral aripiprazole supplementation upon resumption of dosing. Conclusions This PopPK model and model-based simulations were effective means for evaluating aripiprazole lauroxil dosing regimens and management of missed doses. Such analyses play an important role in determining the use of this long-acting antipsychotic in clinical practice.

Long-acting formulations delivering aripiprazole: beyond single-value characterizations of steady-state pharmacokinetics

and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). Neuropsychiatric Disease and Treatment 2017:13 1815–1816 Neuropsychiatric Disease and Treatment Dovepress