Safety Profile of Pimavanserin Therapy in Elderly Patients with Neurodegenerative Disease-Related Neuropsychiatric Symptoms: A Phase 3B Study

Background

Pimavanserin, a 5-HT2A receptor inverse agonist/antagonist, is the only medication approved by the FDA for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis (PDP). Further expanding knowledge of the safety profile of pimavanserin in PDP and neurodegenerative diseases (NDD) such as Alzheimer's disease is of great interest for informing its use in patients with PDP (with or without dementia), given this population is highly sensitive to adverse effects following antipsychotic use.

Objective

This trial evaluated the effects of pimavanserin compared to placebo in frail older adults and elderly patients with neuropsychiatric symptoms related to NDD, such as hallucinations and delusions, to better understand the safety of pimavanserin in this population.

Methods

This was a phase 3b, 8-week treatment (study duration of up to 16 weeks), multicenter, randomized, double-blind, placebo-controlled, two-arm parallel-group trial (NCT03575052). The primary endpoint was safety and tolerability, measured by treatment-emergent adverse events (TEAEs). Secondary safety endpoints were change from baseline in motor and cognitive function; exploratory endpoints included suicidality, sleep quality, and neuropsychiatric symptoms.

Results

Incidences of TEAEs were similar between treatment groups; 29.8% reported ≥1 TEAE (pimavanserin: 30.4%; placebo: 29.3%), and 1.8% reported serious TEAEs (pimavanserin: 2.0%; placebo: 1.5%). Pimavanserin did not impact motor- or cognitive-related function.

Conclusions

Pimavanserin was well tolerated and not associated with motor or cognitive impairment. Together, these findings highlight the manageable and generally favorable safety profile of pimavanserin in patients with NDD, contributing to our knowledge on the safety of pimavanserin as it generalizes to patients with PDP.

Switching to iloperidone: An omnibus of clinically relevant observations from a 12-week, open-label, randomized clinical trial in 500 persons with schizophrenia

OBJECTIVE

To describe secondary analyses from a 12-week, randomized, open-label trial where adult schizophrenia outpatients receiving risperidone, olanzapine, or aripiprazole were switched to iloperidone.

METHODS

Patients were randomized into two groups: one where the antecedent antipsychotic dose was titrated downwards to zero over 2 weeks (n=240), and the other group where the antecedent antipsychotic was abruptly stopped (n=260). Adaptations of the Clinical Global Impression scale were used to evaluate clinical changes. Other assessments included the reporting of adverse events (AEs), study discontinuation, body weight, and metabolic variables.

RESULTS

Improvement was steady throughout the study for both gradual- and immediate-switch groups starting at Week 1 and continuing through Week 12. Discontinuations due to AEs in the first 2 weeks of treatment were higher for the immediate-switch group compared with the gradual-switch group (10.8% vs. 5.4%, NNT 19, 95% CI 10-151). Fewer patients in the gradual-switch group experienced dizziness as an AE, whereas a higher percentage of patients in the immediate-switch group exhibited earlier onset of a therapeutic response within the first 2 weeks; both groups were comparable thereafter with low rates of dizziness and similar efficacy outcomes.

CONCLUSIONS

Switching to iloperidone can be accomplished either with a gradual crossover or immediate discontinuation of the prior antipsychotic; however, the immediate-switch method is associated with greater proportion of initial dizziness. The observed outcomes are consistent with what has been previously reported regarding iloperidone's favorable akathisia/EPS profile and modest impact on somnolence/sedation, body weight, and metabolic variables.

Skin reactions at the application site of rivastigmine patch (4.6 mg/24 h, 9.5 mg/24 h or 13.3 mg/24 h): a qualitative analysis of clinical studies in patients with Alzheimer's disease

BACKGROUND AND OBJECTIVES

Rivastigmine patch is approved for the treatment of all stages of Alzheimer's disease (AD). Application site reactions may be a concern to clinicians and we used two large clinical trial databases to investigate the incidence of skin reactions in patients receiving rivastigmine patch.

METHODS

Data from a 24-week, randomised, double-blind (DB) evaluation of 13.3 vs. 4.6 mg/24 h rivastigmine patch in severe AD (ACTION) and a 72- to 96-week study comprising an initial open-label (IOL) phase followed by a 48-week randomised, DB phase (13.3 vs. 9.5 mg/24 h rivastigmine patch) in declining patients with mild-to-moderate AD (OPTIMA) were analyzed. The incidence, frequency, severity, management and predictors of application site reactions were assessed.

RESULTS

Application site reactions were mostly mild or moderate in severity and reported by similar proportions in each treatment group (

ACTION

13.3 mg/24 h, 24.5% and 4.6 mg/24 h, 24.2%; OPTIMA: IOL 9.5 mg/24 h, 22.9%; DB 13.3 mg/24 h, 11.4% and 9.5 mg/24 h, 12.0%); none were rated serious. In both studies, <9% of patients required treatment for application site reactions. Application site reactions led to discontinuation of 1.7% and 2.5% of the 13.3 mg/24 h and 4.6 mg/24 h groups, respectively, in ACTION, 8.7% in OPTIMA IOL and 1.8% and 3.5% of the 13.3 mg/24 h and 9.5 mg/24 h groups, respectively, in OPTIMA DB.

CONCLUSIONS

Application site reactions were experienced by <25% of patients in both studies, with no notable effect of dose. No reactions qualified as serious and skin reactions were uncommon as a reason for study discontinuation.

A trial evaluating gradual- or immediate-switch strategies from risperidone, olanzapine, or aripiprazole to iloperidone in patients with schizophrenia

In a 12-week randomized open-label trial, adults diagnosed with schizophrenia experiencing inadequate efficacy and/or poor tolerability on risperidone, olanzapine, or aripiprazole were randomized to switch to iloperidone either gradually (ie, down-titration of current therapy over the first 2weeks [to 50% on Day 1, 25% by Week 1, 0% by Week 2]) or immediately. All patients were titrated on iloperidone to 6mg BID by Day 4, then flexibly dosing between 6 and 12mg BID, as needed. The primary variable was the Integrated Clinical Global Impression of Change (I-CGI-C) and the primary analysis time point was Week 12. A total of 500 patients were randomized and received iloperidone (gradual switch, 240; immediate switch, 260), with 175, 155, and 170 patients switched from risperidone, olanzapine, and aripiprazole, respectively. I-CGI-C Results confirmed improved outcomes at Week 12, with scores that were similar between the gradual- and immediate-switch groups, respectively, for risperidone, 2.82 and 2.67 (95% CI: -0.229, 0.511); olanzapine, 2.87 and 3.03 (95% CI: -0.548, 0.235); and aripiprazole, 2.79 and 2.81 (95% CI: -0.405, 0.368). Incidence of adverse events (AEs) was similar in both switch groups, with the most frequently reported (≥10%) being dizziness, dry mouth, somnolence, and weight increase. In conclusion, switching to iloperidone by either a gradual or an immediate method did not reveal any clinically significant differences in ratings of overall efficacy and safety/tolerability outcomes, based on the I-CGI-C at 12weeks. Similar overall safety/AE profiles were observed regardless of the specific agent from which patients were switched.

A 25-week, open-label trial investigating rivastigmine transdermal patches with concomitant memantine in mild-to-moderate Alzheimer's disease: a post hoc analysis

OBJECTIVE

To investigate the tolerability and efficacy of the rivastigmine transdermal patch in patients with mild-to-moderate Alzheimer's disease receiving concomitant memantine.

RESEARCH DESIGN AND METHODS

Post hoc analysis of a 25-week, randomized, prospective, open-label, parallel-group study. Patients receiving donepezil were switched to rivastigmine patches (4.6 mg/24 h) immediately or following a 7-day withdrawal for 4 weeks (core phase), before titrating up to 9.5 mg/24 h for a further 20-week extension phase. Prior memantine therapy was continued throughout.

MAIN OUTCOME MEASURES

Tolerability (adverse events [AEs], serious AEs [SAEs] and discontinuations) and efficacy (cognition, global functioning and activities of daily living [ADLs]) were assessed for the rivastigmine transdermal patch, with or without concomitant memantine.

RESULTS

Overall, 135 and 126 patients received rivastigmine with and without memantine, respectively. Of these, 122 (90.4%) and 118 (93.7%) patients with and without memantine, respectively, completed the core phase; 120 and 114 patients, respectively, entered the extension phase, and 90 (75.0%) and 86 (75.4%) completed the study. The incidences of AEs (73.3 vs. 67.5%) and SAEs (10.4 vs. 7.1%) were both slightly larger in patients receiving concomitant memantine, but the differences were not statistically significant (95% CIs: -5.2, 16.9 and -3.6, 10.1 for AEs and SEAs, respectively). The incidence of gastrointestinal AEs was low in both groups. Discontinuation due to AEs was higher in patients who received memantine (17.0 vs. 11.9%). Changes in cognitive and global function were similar between groups. ADL scores worsened in both groups; significantly more in those treated with memantine.

CONCLUSION

Use of the rivastigmine transdermal patch in patients on established memantine appears to be well-tolerated, with only modest, non-significant increases in AEs compared with monotherapy, and did not seem to affect cognition or global functioning adversely.

A pilot study evaluating the efficacy and safety of rivastigmine in patients with mixed dementia

BACKGROUND AND OBJECTIVE

The two most common causes of dementia in the elderly are Alzheimer's disease (AD) and vascular dementia (VaD), which can coexist as mixed dementia. The object of this study was to assess the efficacy and safety of rivastigmine in patients with mixed dementia (AD with VaD).

STUDY DESIGN

This 26-week open-label pilot study was conducted at 19 centres in the US. To reduce bias, the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) raters were blinded to all efficacy measures and to patient dosage information. Patients were treated with rivastigmine and titrated to their highest tolerated dose, up to 12 mg/day (6 mg twice daily). The primary efficacy measure was cognitive function assessed by the ADAS-Cog subscale (without the concentration/distractibility item, to be consistent with cognitive outcome measures used in previous rivastigmine trials).

RESULTS

Forty-seven percent of patients treated with rivastigmine 6-12 mg/day demonstrated improvement on the ADAS-Cog at 26 weeks, with >25% of patients having a clinically significant improvement of > or =4 points. Treatment with rivastigmine (6-12 mg/day) was well tolerated by the majority of patients. The most common adverse effects occurring in >10% of patients were nausea, vomiting, dizziness and diarrhoea.

CONCLUSION

This pilot study suggests that rivastigmine treatment may have beneficial effects in the treatment of patients with mixed dementia.

D1 receptor alleles predict PET metabolic correlates of clinical response to clozapine

A goal of pharmacogenetics is to clarify associations between allelic variation and risk factors in psychiatric illness. We report changes in regional brain metabolism based on dopamine alleles. Treatment-resistant schizophrenic subjects were positron emission tomography scanned with 18F-fluorodeoxyglucose after 5 weeks each of placebo and clozapine treatment. Significant regional brain metabolic effects were found for the D1 receptor genotypes (P < 0.05), adjusted for multiple comparisons. Metabolic decreases for the 2,2 genotype but not the 1,2 genotype were observed in all major sectors of the brain, with the exception of the ventral parts of the caudate and putamen. Frontal, temporal, parietal, and occipital neocortices showed decreased metabolism as did the cingulate juxta-allocortex and the parahippocampal allocortex. Decreases were also observed in the thalamus, amygdala, and cerebellum bilaterally. No significant metabolic differences by genotype were observed for D3, 5HT(2A), and 5HT(2C) polymorphisms. In terms of clinical response, the DRD1 2,2 genotype significantly improved with clozapine treatment, demonstrating a 30% decrease in the Brief Psychiatric Rating Scale positive symptoms in contrast to a 7% worsening for the 1,2 genotype (P < 0.05). In this preliminary study, brain metabolic and clinical response to clozapine are related to the D1 receptor genotype.

Brain metabolic and clinical effects of rivastigmine in Alzheimer's disease

In-vivo metabolic measures with positron emission tomography using (18)F-fluorodeoxyglucose (FDG-PET) have demonstrated hypometabolism in temporal, frontal, and hippocampal areas during the early stages of Alzheimer's disease (AD). Progression of the dementia in AD involves compromised cholinergic functioning. Cholinesterase inhibitors have demonstrated efficacy in improving cognition and behaviour in AD. In this study, we demonstrate the usefulness of FDG-PET in measuring the progression of untreated AD and its modification by treatment with rivastigmine (Exelon, Novartis Pharmaceuticals, East Hanover, New Jersey, USA), a centrally selective cholinesterase inhibitor of the carbamate type. Patients with mild to moderate probable AD (Mini-Mental Status Exam scores of 10-26, inclusive) were enrolled in a double-blind, placebo controlled comparison of three fixed daily doses of rivastigmine (3, 6, or 9 mg/d) or placebo for 26 wk. FDG-PET scans were obtained on 27 patients at baseline and following 26 wk of treatment using the Snodgrass Picture Naming activation task. A total of 71.4% of the patients treated with placebo deteriorated clinically compared to only 25.0% of the patients treated with rivastigmine (chi2 = 4.8; p & 0.03). Rivastigmine-responders (i.e. those who clinically improved or remained clinically stable as measured by the Clinicianaposs Interview-Based Impression of Change-plus) showed a marked increase in brain metabolism (p <0.01) involving, but not limited to, structures comprising the memory-related cortices and the prefrontal system. These metabolic changes were not observed in the placebo-treated patients or the rivastigmine non-responders. Of note is that responders increased hippocampal metabolism by 32.5% (p < 0.03) compared to a non-significant decrease in the non-responders (6.4%) and placebo-treated patients (4.1%). These results are consistent with the literature suggesting that FDG-PET can sensitively measure the progression of AD and its improvement with cholinesterase inhibitors. Rivastigmine prevented the expected deterioration in clinical status and dramatically increased brain metabolic activity in a majority of patients.

A functional polymorphism of the cytochrome P450 1A2 (CYP1A2) gene: association with tardive dyskinesia in schizophrenia

Tardive dyskinesia (TD) is a common and potentially irreversible side effect associated with long-term treatment with typical antipsychotics. Approximately, 80% or more of patients with schizophrenia are smokers. Smoking is a potent inducer of the CYP1A2 enzyme, and is known to cause a significant decrease in plasma concentrations of some antipsychotics. Therefore, person-to-person differences in the extent of CYP1A2 induction by smoking may contribute to risk for the development of TD. Recently, a (C-->A) genetic polymorphism in the first intron of the CYP1A2 gene was found to be associated with variation in CYP1A2 inducibility in healthy volunteer smokers. The aim of this study was to test the clinical importance of the (C-->A) polymorphism in CYP1A2 in relation to TD severity. A total of 85 patients with schizophrenia were assessed for TD severity using the Abnormal Involuntary Movement Scale (AIMS), and were subsequently genotyped for the (C-->A) polymorphism in CYP1A2. The mean AIMS score in patients with the (C/C) genotype (associated with reduced CYP1A2 inducibility) was 2.7- and 3.4-fold greater than in those with the (A/C) or (A/A) genotype, respectively (F[2,82] = 7.4, P = 0.0007). Further, a subanalysis in the 44 known smokers in our sample, revealed a more pronounced effect. The means AIMS score in smokers was 5.4- and 4. 7-fold greater in (C/C) homozygotes when compared to heterozygotes and (A/A) homozygotes, respectively (F[2,41] = 3.7, P = 0.008). These data suggest that the (C-->A) genetic polymorphism in the CYP1A2 gene may serve as a genetic risk factor for the development of TD in patients with schizophrenia. Further studies in independent samples are warranted to evaluate the applicability of our findings to the general patient population receiving antipsychotic medications.

Lack of relationship between lactose absorption and senile cataracts

In a double-blind study using the hydrogen breath-excretion test to identify lactase status, we found 45% of absorbers in a group of 64 patients with senile cataracts compared with 71% of absorbers in the control group. These results oppose the hypothesis that lactose absorbers are especially prone to develop senile cataracts.