Effectiveness of paliperidone long-acting injection in clinical practice

Background:
The efficacy of the long-acting injectable formulation of the antipsychotic paliperidone (paliperidone palmitate) has been investigated in randomized controlled trials. Due to the nature of study designs, these may not be representative of usual clinical practice. The aim of this study was to assess the clinical effectiveness of the long-acting injectable antipsychotic paliperidone palmitate using treatment continuation at 1 year as an outcome.

Methods:
Patients were initiated on paliperidone palmitate prior to December 2014 in a single health board in Wales (UK). Demographic factors that may have influenced outcome, including diagnosis, age at initiation, sex, inpatient or outpatient status on initiation, were analysed to assess whether they influenced patient outcome. For patients completing 1 year of treatment, inpatient stay in the 12 months prior to and following paliperidone palmitate initiation was compared.

Results:
Data were available for 64 patients; 41 had a diagnosis of schizophrenia and 7 had previously received clozapine. Continuation rates at 6 and 12 months were 69% and 63% respectively. Treatment continuation was not associated with demographic factors. For continuers, mean inpatient stay pre- and post-initiation was 83.2 ± 105.3 and 73.5 ± 103.3 days respectively (p = 0.61). The most common reason for discontinuation was lack of effect (n = 9).

Conclusions:
The proportion of patients remaining on treatment was comparable to that reported in other naturalistic studies. Prescribing for indications outside the product licence was relatively common, but did not appear to influence outcome, although the number of patients in each group was small. Treatment continuation at 6 months appeared to be a predictor of longer-term outcome.