Joris Berwaerts

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.

A randomized, placebo- and active-controlled study of paliperidone extended-release as maintenance treatment in patients with bipolar I disorder after an acute manic or mixed episode

BACKGROUND Paliperidone ER monotherapy was efficacious in treating acute mania in two 3-week studies in patients with bipolar I disorder. We assessed its efficacy in a study investigating maintenance treatment of clinically stable patients with this disorder. METHODS Patients (n=766), aged 18 to 65 years inclusive, with current manic or mixed episodes were initially randomized (4:1) to flexibly-dosed paliperidone ER (3-12 mg/day) or olanzapine (5-20 mg/day; 3-week acute treatment phase); responders continued the same treatment (12-week continuation phase). Patients on paliperidone ER who achieved remission during this phase were randomized (1:1) to fixed-dose paliperidone ER (n=152) or placebo (n=148); those on olanzapine continued to receive that at fixed dose (n=83) (maintenance phase). RESULTS Median time to recurrence of any mood symptoms (primary endpoint) was: 558 days (paliperidone ER), 283 days (placebo) and not observed with olanzapine (<50% of patients experienced recurrence). Time to recurrence of any mood symptoms was significantly longer with paliperidone ER than placebo (p=0.017; based on weighted Z-test at 0.0198 significance level; hazard ratio [placebo: paliperidone ER; unweighted 95% confidence interval]: 1.43 [1.03; 1.98]); the difference was significant for preventing recurrence of manic, but not depressive, symptoms. Treatment-emergent adverse events (maintenance phase) occurred more often in olanzapine group (64%) than placebo (59%) or paliperidone ER groups (55%). LIMITATIONS Responder-enriched design prevents extrapolation of data to patients not previously stabilized on paliperidone ER. CONCLUSIONS Paliperidone ER significantly delayed the time to recurrence of any mood symptoms, versus placebo, in patients with bipolar I disorder. No new safety concerns emerged.

Population pharmacodynamic modeling of various extended-release formulations of methylphenidate in children with attention deficit hyperactivity disorder via meta-analysis

Placebo and pharmacodynamic (PD) models were developed which link temporal measures of efficacy in children with attention deficit hyperactivity disorder (ADHD) and methylphenidate (MPH) plasma concentrations from adults. These models can be used to predict daily pediatric clinical measure profiles following administration of different MPH formulations in children without conducting pediatric pharmacokinetic (PK) or PD studies by using more easily obtained adult PK data. Mean PK data from various extended-release MPH formulations studied in adults and mean PD data from nine pediatric efficacy studies were obtained from the literature. The individual time-course of the clinical measures from three pediatric trials were also analyzed after being combined with the meta-analysis data. The clinical measure profiles following placebo administration were described by indirect response models with time-varying elimination rates. MPH pharmacodynamic effect was described by Emax models, which included time-dependent tolerance. Internal and external evaluations using a visual predictive check technique confirmed the prediction capability of the models. This modeling exercise demonstrated that time courses of MPH concentrations in adults with different drug release patterns can be used to predict time courses of clinical efficacy parameters in pediatrics by employing the models developed by meta-analysis.

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.

Practical guidance for dosing and switching from paliperidone palmitate 1 monthly to 3 monthly formulation in schizophrenia

Abstract Objective: This commentary summarizes recommended dosing strategies for a recently developed 3 monthly long-acting injectable1 (LAI) formulation of paliperidone palmitate (PP3M) for the treatment of schizophrenia in adults. Methods: Recommendations for different dosing scenarios are based on the pharmacokinetic, efficacy and safety outcomes from phase 1 and phase 3 studies, population pharmacokinetic models, and model based simulations. Results: Switching to PP3M treatment is recommended only in patients previously treated with once monthly paliperidone palmitate LAI (PP1M) for at least 4 months. The first injection of PP3M (175 to 525 mg equivalent [eq.]) should be given at the time of next scheduled injection of PP1M as a 3.5-fold multiple of the last PP1M dose (50–150 mg eq.), with a dosing window of ±1 week. Following that first injection of PP3M, once-every-three-months maintenance injections with PP3M are recommended, with a dosing window of ±2 weeks. The doses of PP3M can be administered in either deltoid (≥90 kg: 1.5 inch 22 G needle; <90 kg: 1.0 inch 22 G needle) or gluteal muscles (1.5 inch 22 G needle regardless of weight). In patients with mild renal impairment (creatinine clearance: 50–80 mL/min), a 25% dose reduction in PP1M and subsequent switching to a corresponding 3.5-dose multiple of PP3M (but not exceeding 350 mg eq.) is recommended. Appropriate dosing is recommended in elderly patients with diminished renal function not exceeding mild renal impairment. Similarly to PP1M, PP3M is not recommended in patients with moderate/severe renal impairment. Like PP1M, no dosage adjustment is required in patients with mild or moderate hepatic impairment or elderly patients with normal renal function. Conclusions: These data provide clinical guidelines for the optimum use of PP3M in patients with schizophrenia previously treated with PP1M for at least 4 months. Registration: ClinicalTrials.gov identifier: NCT01559272 and NCT01529515.

Limited utility of number needed to treat and the polarity index for bipolar disorder to characterize treatment response.

The medical community increasingly supports the use of simplifying constructs or ratios to facilitate incorporation of evidence-based medicine into clinical practice such as number needed to treat (NNT) and polarity index (PI). Clinicians and teachers find them to be an appealing, easy-to remember integer that can be readily translated into clinical practice. However, serious questions have been raised with respect to the validity, reliability and value of these descriptors of response. This commentary identifies some of the specific limitations of the NNT and PI constructs when applied to treatments of bipolar disorder.

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.

Doctor shopping for medications used in the treatment of attention deficit hyperactivity disorder: shoppers often pay in cash and cross state lines.

Abstract Background: Doctor shopping, defined by filling overlapping prescriptions from more than one prescriber at more than two pharmacies, is a way to obtain scheduled medications for diversion or abuse. Little is known about how far attention deficit hyperactivity disorder (ADHD) medication shoppers travel, how often they cross state lines to fill their ADHD prescriptions and how often they pay for their medication in cash, i.e. entirely out of pocket. Objective: We sought to describe the pattern of doctor shopping for ADHD medications: how far shoppers travel, how often they cross state lines to fill their prescriptions, and how often they pay in cash. Methods: Retrospective cohort study using LRx, a large US retail prescription database. We included subjects with any ADHD medication dispensed between 2011 and 2012. Subjects were followed for 18 months. Results: Of a total of 4 402 464 subjects exposed to ADHD medications, 0.4% developed shopping behavior. Women were more likely to become shoppers. Shoppers travelled a median of 91.9 miles and non-shoppers 0.2 miles to fill their ADHD prescriptions. Almost 28% of the shoppers filled prescriptions in >1 state compared with 4.3% of non-shoppers. Of the shoppers, 27.3% paid at least one prescription in cash compared to 14.4% of the non-shoppers. Conclusions: Shoppers travelled larger distances, visited more states and paid in cash for ADHD medications more often than non-shoppers. Data sharing among prescriptions monitoring programs can improve their effectiveness and drug utilization studies should take account of cash purchases.