Efficacy and safety of second-generation antipsychotic long-acting injections (SGA LAIs) in maintenance treatment of bipolar disorder: protocol for a systematic review and meta-analysis

Second-generation antipsychotic long-acting injections in bipolar disorder: Systematic review and meta-analysis

BACKGROUND

Non-adherence is a significant problem in bipolar disorder. Second-generation antipsychotics (SGA) long-acting injections (LAIs) may improve adherence in bipolar disorder and may prevent relapses. However, the evidence is limited and conflicting.

OBJECTIVE

The objective of this study was to evaluate efficacy and safety of SGA LAIs in bipolar disorder.

METHOD

Systematic review and meta-analysis of randomised controlled trials (RCTs) (≥6 months duration) investigating safety and efficacy of SGA LAIs for bipolar disorder. We searched Pubmed, Embase, CINAHL, Cochrane, PsycINFO, LiLACS, www.clinicaltrials.gov up to October 2016. We also contacted the manufacturers of SGA LAIs. Primary efficacy and safety outcomes were relapse rate and all-cause discontinuation respectively.

RESULTS

Total of seven RCTs (n = 1192) were included. SGA LAIs show superiority over placebo for study-defined relapse rate (RR = 0.58, 95% CI = 0.49-0.68, P < 0.00001) and all-cause discontinuation (RR = 0.72, 95% CI = 0.64-0.82, P < 0.00001). However, no significant difference was found between SGA LAIs and oral active control for relapse rate (RR = 0.92, P = 0.79) and all-cause discontinuation (RR = 1.2, P = 0.31). In terms of secondary outcomes, SGA LAIs performed better than placebo in relapse to mania/hypomania, young mania rating scales (YMRS), clinical global impression-severity (CGI-S), montgomery-asberg depression rating scale (MADRS). There was no significant difference between SGA LAIs and oral active control regarding relapse to mania/hypomania, YMRS, CGI-S, extra-pyramidal side effects (EPSEs), weight gain. However, the active control performed better than SGA LAIs in relapse to depression, MADRS, and prolactin-related AEs.

CONCLUSIONS

Current evidence is very limited to support the use of SGA LAIs (compared to oral medication) in bipolar disorder. Further high-quality studies, particularly comparing SGA LAIs with active control, are warranted.

Rats and rabbits as pharmacokinetic screening tools for long acting intramuscular depots: case study with paliperidone palmitate suspension

Development of prodrug of 9-hydroxyrisperidone (paliperidone) long-acting intramuscular injection has enabled delivery over four-week time period with improved compliance. The key aim of this work was to establish a reliable preclinical model which may potentially serve as a screening tool for judging the pharmacokinetics of paliperidone formulation(s) prior to human clinical work. Sparse sampling composite study was used in rats, (Wistar/Sprague-Dawley (SD; n = 10)) and a serial blood sampling study design was used in rabbits (n = 4). Animals received intramuscular injection of paliperidone palmitate in the thigh muscle at dose of 16 (rats) and 4.5 mg/kg (rabbits). Samples were drawn in rats (retro-orbital sinus) and rabbits (central ear artery) and were analysed for paliperidone using liquid chromatography-mass spectrometry/ mass spectrometry (LC-MS/MS) assay. The plasma data was subjected to pharmacokinetic analysis. Following intramuscular injection of depot formulation in Wistar/SD rats and rabbits, absorption of paliperidone was slow and gradual with median value of time to reach maximum concentration (T_max) occurring on day 7. The exposures (i.e. area under the curve (AUC; 0-28) days) were 18,597, 21,865 and 18,120 ng.h/mL, in Wistar, SD and rabbits, respectively. The clearance was slow and supported long half-life (8-10 days). Either one of the two models can serve as a research tool for establishing pharmacokinetics of paliperidone formulation(s).