Bart Remmerie

Efficacy and Safety of the 3-Month Formulation of Paliperidone Palmitate vs Placebo for Relapse Prevention of Schizophrenia: A Randomized Clinical Trial

IMPORTANCE Treatment nonadherence and relapse are common problems in patients with schizophrenia. The long-acting 3-month formulation of paliperidone palmitate, owing to its extended elimination half-life, may offer a valuable therapeutic option for these patients. OBJECTIVE To evaluate the efficacy and safety of the 3-month formulation of paliperidone palmitate vs placebo in delaying time to relapse of schizophrenia symptoms. DESIGN, SETTING, AND PARTICIPANTS This randomized, multicenter trial conducted from April 26, 2012, through April 9, 2014, in 8 countries consisted of 4 phases: 3-week screening phase, flexible-dose 17-week open-label transition phase, 12-week open-label maintenance phase, and open-ended double-blind (DB) phase. Of the 506 patients enrolled (aged 18-70 years; DSM-IV-TR diagnosis of schizophrenia), 305 were randomized to 3-month paliperidone palmitate (n = 160) or placebo (n = 145) in the DB phase. INTERVENTIONS Patients received once-monthly doses of the 1-month formulation of paliperidone palmitate (50, 75, 100, or 150 mg eq) during the transition phase, followed by a single dose of the 3-month formulation (3.5 times the stabilized dose of once-monthly paliperidone palmitate) during the maintenance phase. Stabilized patients were randomized to receive either a fixed dose of 3-month paliperidone palmitate (175, 263, 350, or 525 mg eq) or placebo once every 3 months during the DB phase. MAIN OUTCOMES AND MEASURES Time from randomization to the first relapse event (time to relapse) in the DB phase. RESULTS In the interim analysis, time to first relapse was significantly different in favor of the paliperidone palmitate group vs the placebo group (hazard ratio = 3.45; 95% CI, 1.73-6.88; P < .001); median time to relapse was 274 days for placebo but not estimable for 3-month paliperidone palmitate. An independent data monitoring committee recommended early study termination due to efficacy. In the DB phase, 183 of 305 patients (62% with 3-month paliperidone palmitate; 58% with placebo) had at least 1 treatment-emergent adverse event; those noted more frequently in the group receiving paliperidone palmitate than in the placebo group were headache (9% vs 4%), weight increased (9% vs 3%), nasopharyngitis (6% vs 1%), and akathisia (4% vs 1%). CONCLUSIONS AND RELEVANCE Compared with placebo, the 3-month formulation of paliperidone palmitate administered 4 times yearly significantly delayed time to relapse in patients with schizophrenia. The 3-month formulation was generally tolerable and has a safety profile consistent with other marketed paliperidone formulations. TRIAL REGISTRATION clinicaltrials.gov Identifier:NCT01529515.

Pharmacokinetics, safety, and tolerability of paliperidone palmitate 3-month formulation in patients with schizophrenia: A phase-1, single-dose, randomized, open-label study

This multicenter, randomized, open‐label, parallel‐group, phase‐1 study assessed the pharmacokinetics (PK), safety, and tolerability of the investigational intramuscular paliperidone palmitate 3‐month (PP3M) formulation in patients with schizophrenia or schizoaffective disorder. A total of 328 patients (men or women, aged 18–65 years) were enrolled in 1 of 4 separately conducted panels (A to D). Each panel had 2 single‐dose treatment periods (period 1, 1 mg intramuscular paliperidone immediate release [IR]; period 2, intramuscular PP3M 75−525 mg eq) separated by a washout of 7–21 days. Overall, 245 of 308 (79.5%) PP3M‐dosed patients completed the study. Because the PK studies of panels A and C were compromised by incomplete injection in some patients, PK data from only panels B and D are presented. Safety data from all panels are presented. Peak paliperidone plasma concentration was achieved between 23 and 34 days, and apparent half‐life was ∼2–4 months. Mean plasma AUC∞ and Cmax of paliperidone appeared to be dose‐proportional. Relative bioavailability in comparison with paliperidone was ∼100% independent of the dose and injection site. Headache and nasopharyngitis were the most common (>7%) treatment‐emergent adverse events. Overall, safety and tolerability were similar to those of the 1‐month formulation. Results support a once‐every‐3‐months dosing interval in patients with schizophrenia or schizoaffective disorder.

A single-dose, open-label, parallel, randomized, dose-proportionality study of paliperidone after intramuscular injections of paliperidone palmitate in the deltoid or gluteal muscle in patients with schizophrenia.

Paliperidone palmitate (PP) is a long‐acting injectable (LAI) antipsychotic, developed for monthly intramuscular (i.m.) administration into deltoid/gluteal muscle, approved for the treatment of schizophrenia in many countries. To assess the options for i.m. injection sites, dose‐proportionality of PP was investigated after injection of a single dose (25–150 mg eq.) of PP in either gluteal (n = 106) or deltoid (n = 95) muscle of schizophrenic patients. Overall, mean (geometric) area under plasma concentration–time curve from time zero to infinity (AUC∞) of paliperidone increased proportionally with increasing PP doses, regardless of injection site. Mean maximum plasma concentration (Cmax) was slightly less than dose‐proportional for both injection sites at PP doses >50 mg eq. Mean Cmax was higher after injection in the deltoid compared with the gluteal muscle, except for the 100 mg eq. dose, while AUC∞ for both injection sites was comparable at all doses. Median time to reach Cmax (tmax) ranged from 13–14 days after deltoid and 13–17 days after gluteal injection across all doses. Single PP injections in deltoid and gluteal muscles in the dose range of 25–150 mg eq. were generally tolerable both locally and systemically.

Effect of carbamazepine on the pharmacokinetics of paliperidone extended‐release tablets at steady‐state

Given the potential concomitant use of carbamazepine and paliperidone extended‐release (ER) in the treatment of schizophrenia or schizoaffective disorder, this open‐label, two‐treatment sequential study investigated the effect of repeated administration of carbamazepine on the steady‐state pharmacokinetics of paliperidone. Sixty‐four patients with a diagnosis of schizophrenia or bipolar‐I disorder received the following treatments in a fixed sequential order, without washout between treatments: (i) paliperidone ER 6 mg tablet once daily for 7 days, and (ii) paliperidone ER 6 mg once daily concomitantly with carbamazepine 200 mg twice daily for the subsequent 21 days. Upon coadministration with carbamazepine, paliperidone steady‐state total exposure (AUC24 h) and peak plasma concentrations (Cmax) decreased by approximately 37% [LSM ratio—AUC24 h: 63.4 (90% CI: 57.19; 70.29); Cmax: 62.47 (90% CI: 55.77; 69.98)]. This decrease is accounted for to a substantial degree by a 35% increase in renal clearance of paliperidone, likely as a result of induction of renal P‐glycoprotein by carbamazepine. A 14% decrease in the amount of drug excreted unchanged in the urine suggests that carbamazepine coadministration has a limited effect on the intestinal absorption or cytochrome metabolism of paliperidone.

Drug-Drug Interaction Studies of Paliperidone and Divalproex Sodium Extended-Release Tablets in Healthy Participants and Patients with Psychiatric Disorders

The objective of these 2 phase 1, open‐label, 2‐treatment, single‐sequence studies was to evaluate the effect of repeated oral doses of divalproex sodium extended‐release (ER) on the pharmacokinetics (PK) of a single dose of paliperidone ER in healthy participants (study 1), and the effect of multiple doses of paliperidone ER on the steady‐state PK of valproic acid (VPA) in patients with psychiatric disorders (study 2), respectively. In study 1 healthy participants received, in a fixed sequential order, treatment A, paliperidone ER 12 mg (day 1); treatment B, VPA 1000 mg (2 × 500 mg divalproex sodium ER) once daily (days 5 to 18) and paliperidone ER 12 mg (day 15). In study 2 patients received treatment A, VPA (days 1–7); treatment B, VPA + paliperidone ER 12 mg (days 8–12). Divalproex sodium ER doses (study 2) were individualized such that systemic therapeutic VPA exposure from prior treatment was maintained on entry into the study. PK assessments were performed at prespecified time points (paliperidone days 1 and 15 [study 1]; VPA days 7 and 12 [study 2]). The oral bioavailability of paliperidone was increased by an estimated 51% (Cmax) and 51%–52% (AUCs) when coadministered with divalproex sodium ER. No effect on the steady‐state plasma concentration of VPA was observed following repeated coadministration with paliperidone ER: the 90%CI around the VPA exposure ratios for the 2 treatments was within the 80%–125% bioequivalence criteria for Cmax,ss and AUCτ. Both VPA and paliperidone ER were well tolerated, and no new safety concerns were identified.

Pharmacokinetic profile after multiple deltoid or gluteal intramuscular injections of paliperidone palmitate in patients with schizophrenia

Paliperidone palmitate (PP) is a once‐monthly long‐acting injectable antipsychotic approved for the treatment of schizophrenia in many countries. To evaluate the different injection‐site options, we compared the pharmacokinetic profile of paliperidone after multiple injections of PP 100 mg eq. (156 mg of PP, equivalent to 100 mg of paliperidone) on days 1, 8, 36, and 64 into the deltoid (n = 24) or gluteal muscle (n = 25) in patients with schizophrenia. After four injections in the deltoid muscle, paliperidone exposure was higher for AUCτ and Cmax, compared with the gluteal muscle (geometric mean AUCτ‐based ratio: 120% [90% CI: 93.1–154.7%], and geometric mean Cmax‐based ratio: 130% [90% CI: 100.6–168.9%]). The mean [SD] fluctuation index was higher, with a larger interpatient variability, after deltoid‐injections (75.9% [30.9%]) than gluteal‐injections (58.5% [14.3%]). The median tmax was similar for both sites. PP was generally tolerable in patients, with more favorable local‐site tolerability for gluteal‐injection. In conclusion, to achieve therapeutic‐concentrations quickly, the first‐two injections of PP are best administered into the deltoid muscle, whereas thereafter maintenance‐injections can be administered either in the deltoid or gluteal muscle.

Determination of Plasma Concentration Reference Ranges for Risperidone and Paliperidone.

Schizophrenia is a common disease managed by a range of interventions, with the primary treatment being antipsychotic medications (APS). Inadequate response, lack of adherence, and/or adverse events often prevent optimal therapeutic effects or therapeutic efficiency. Monitoring APS plasma concentrations can be used together with a full clinical evaluation to help improve patient care or offer better treatment options for the patient. To enable interpretation of individual risperidone and paliperidone plasma concentrations, we developed “reference ranges,” which consider the expected variability in plasma concentrations between subjects across the population, rather than representing a “therapeutic range” that relates to efficacy and/or safety outcomes. The reference ranges were derived from population pharmacokinetic models, which varied based upon administration route, dose, and time after dose. Good agreement between the proposed reference ranges and external data was obtained through graphical and numerical evaluations, indicating they could be reliably used in clinical practice.

Optimizing Antipsychotic Patient Management Using Population Pharmacokinetic Models and Point‐of‐Care Testing

Schizophrenia is a common disease, characterized by progressive functional decline exacerbated by psychotic relapses that often result from a lack of full adherence to antipsychotic (APS) medication. Although atypical APS medications do not have clear therapeutic windows, as generally required for therapeutic drug monitoring (TDM), measuring APS plasma levels in the context of a population expected range at the point‐of‐care (POC) may provide valuable clinical insights for differentiating lack of efficacy from a lack of adherence to medication.

Prospective dose selection and acceleration of paliperidone palmitate 3‐month formulation development using a pharmacometric bridging strategy

AIMS To prospectively select the dose of the paliperidone palmitate 3-month (PP3M) formulation, using a pharmacometric bridging strategy based on the paliperidone palmitate 1-month (PP1M) formulation previously approved for schizophrenia treatment. METHODS Pharmacokinetic (PK) data from a 6-month interim analysis of a single dose PP3M Phase I clinical trial was integrated with a previously developed PP1M population-PK model. The model was updated to incorporate formulation as a covariate on absorption parameters and to explore the most critical design element of the Phase III study: the PP1M-to-PP3M dose multiplier for patients switching formulations. Plasma paliperidone concentrations were measured at predetermined intervals during Phase III, enabling comparison of the multiple-dose PK between PP1M and PP3M. Exposure matching was assessed graphically to determine whether paliperidone plasma concentrations from the two formulations overlapped. RESULTS Prospective steady-state PK simulations revealed that a 3.5 multiple of the PP1M dose would yield a corresponding PP3M dose with comparable exposure. The prospective pharmacometric simulation and observed Phase III PK data agreed closely. Phase III results confirmed the hypothesis that efficacy of PP3M was noninferior to that of PP1M. The similarity in exposures between the two formulations was likely a key determinant of the equivalent efficacy between the two products observed in the Phase III study. CONCLUSIONS Successful prospective PP3M Phase III clinical trial dose selection was achieved through the use of pharmacometric bridging, without conducting a Phase II study and using only limited Phase I data for PP3M. We estimate that this strategy reduced development time by 3-5 years and may be applicable to other drug development projects.

Comparison of Capillary and Venous Drug Concentrations After Administration of a Single Dose of Risperidone, Paliperidone, Quetiapine, Olanzapine, or Aripiprazole

Risperidone, paliperidone, quetiapine, olanzapine, and aripiprazole are antipsychotic drugs approved for treating various psychiatric disorders, including schizophrenia. The objective of this randomized, parallel‐group, open‐label study was to compare finger‐stick‐based capillary with corresponding venous whole‐blood and plasma concentrations for these drugs after administration of a single dose to healthy volunteers. All whole‐blood and plasma drug concentrations were measured with validated liquid chromatography–tandem mass spectrometry methods. Capillary and venous concentrations (both in plasma and whole blood) were in close agreement, although a time‐dependent difference was observed, most obviously for olanzapine and paliperidone, with slightly higher capillary versus venous drug concentrations during the first hours after administering a single dose. The observed difference between capillary and venous plasma drug concentrations is expected not to be relevant in clinical practice, considering the wide window of therapeutic concentrations and the wide range of drug concentrations in the patient population for a given dose. Based on these results, finger‐stick‐based capillary drug concentrations have been shown to approximate venous drug concentrations.