Adherence to Background Antipsychotic and Pimavanserin in Patients with Schizophrenia: Post Hoc Analyses from the ENHANCE and ADVANCE Studies.

Background: In patients with schizophrenia, study design to optimize adherence and objective measurement of adherence is critical for interpreting results. Two randomized, double-blind studies evaluating adjunctive pimavanserin in patients with schizophrenia who received stable antipsychotic treatment included measures to encourage and assess treatment adherence. Objective: This post hoc analysis evaluated adherence levels achieved in the Phase III ENHANCE study (NCT02970292) and the Phase II ADVANCE study (NCT02970305). Methods: Blood levels of participants receiving adjunctive treatment with pimavanserin or placebo added to their ongoing antipsychotic medication were tested and evaluated regularly throughout both studies. For both the background antipsychotic and pimavanserin, treatment adherence was defined as a blood sample test result above the lower limit of quantification. Results: Overall, 392 of 633 screened patients and 403 of 608 screened patients were in the safety populations in ENHANCE and ADVANCE, respectively. In ENHANCE, at weeks 1, 3, and 6/early termination (ET), the adherence rates remained ≥ 95.1% for the background antipsychotic in both pimavanserin and placebo treatment groups and ≥ 96.8% for pimavanserin. In ADVANCE, high adherence rates (≥90.6%) with the background antipsychotic (for both treatment groups) and pimavanserin (≥95.0%) were observed at weeks 2, 8, 14, and 26/ET. Conclusion: Rigorous screening was performed to exclude patients not adherent to their background antipsychotic before enrollment and to pimavanserin during study visits by using regular blood sampling. Mandatory caregiver participation further supported adherence to study treatment and procedures. These efforts may have contributed to the high levels of adherence to both background antipsychotic and pimavanserin reported in ENHANCE and ADVANCE.

Effects of adjunctive pimavanserin and current antipsychotic treatment on QT interval prolongation in patients with schizophrenia.

Background: Pimavanserin prolongs the QT interval, with mean increases in corrected QT (QTc) of 5-8 ms, and is currently being investigated for the treatment of negative symptoms of schizophrenia. Objectives: To assess QT interval prolongation in 3 studies investigating once-daily pimavanserin as an adjunct to current antipsychotic treatment in patients with schizophrenia. Methods: Electrocardiograms were unblinded from trials in which pimavanserin or placebo was added to main antipsychotics over 6 weeks (ENHANCE), 26 weeks (ADVANCE), and up to 78 weeks (ongoing 52-week, open-label extension study [study 035]) of treatment. Antipsychotic treatment was permitted throughout these studies. The 3 most frequently used antipsychotic treatments were examined-aripiprazole (including long-acting injectable), risperidone (including long-acting injectable), and olanzapine. QT intervals were corrected (QTc) using Fridericia's method, with elevated risk defined as either postbaseline value maximum of >500 ms or change from baseline to postbaseline maximum of >60 ms. Results: Of patients treated with adjunctive pimavanserin in ENHANCE, there were no postbaseline QTc values >481 ms; one patient in each of the risperidone and aripiprazole groups had change from baseline to postbaseline maximum >60 ms. More patients had change from baseline to postbaseline maximum ranging from 31 to 60 ms in the risperidone plus adjunctive placebo group (n = 5; 6.6%) than those in the risperidone plus adjunctive pimavanserin group (n = 3, 4.1%). In the pimavanserin plus antipsychotic group of ADVANCE, one patient had postbaseline QTc value >481 ms, and one patient treated with aripiprazole had change from baseline to postbaseline maximum of >60 ms. In study 035, a change from double-blind baseline to overall postbaseline maximum >60 ms occurred in one patient treated with aripiprazole and pimavanserin and in one patient treated with risperidone and pimavanserin. Similar proportions of patients had changes from double-blind baseline to post double-blind baseline maximum between 31 and 60 ms across treatments. No adverse events associated with an increase in the QTc interval were reported. Conclusions: Adjunctive pimavanserin with background antipsychotic treatment showed no evidence of QTc prolongation >500 ms postbaseline, consistent with previously reports on QT prolongation with pimavanserin.

Pimavanserin for negative symptoms of schizophrenia: results from the ADVANCE phase 2 randomised, placebo-controlled trial in North America and Europe.

BACKGROUND: Negative symptoms of schizophrenia are associated with adverse clinical outcomes, but there are few effective treatments. We aimed to assess the effects of pimavanserin, a selective 5-HT2A inverse agonist and antagonist, on negative symptoms of schizophrenia. METHODS: The ADVANCE study was a phase 2, 26-week, randomised, double-blind, placebo-controlled study of pimavanserin in stable outpatients with schizophrenia aged 18-55 years with predominant negative symptoms. Patients were randomly assigned (1:1) across 83 sites (18 in North America and 65 in Europe) to receive pimavanserin or placebo daily, added to an ongoing antipsychotic medication, per a computer-generated schedule (stratification by geographical region). Eligible patients had a score of at least 20 on the sum of seven Positive and Negative Syndrome Scale (PANSS) Marder negative factor items (and scores of ≥4 on at least three or ≥5 on at least two of negative symptom items). The starting dosage of 20 mg of pimavanserin or placebo could be adjusted to 34 mg or 10 mg within the first 8 weeks of the study, after which dosage remained stable until the end of the study. Both pimavanserin and placebo were administered orally once daily as two individual tablets (pimavanserin tablets were either 10 mg or 17 mg). The primary endpoint was change in total score using the 16-item Negative Symptom Assessment (NSA-16) from baseline to week 26. Primary outcomes were analysed in patients who received at least one dose of the study drug and had NSA-16 assessments at baseline and at least once post-baseline (full analysis set). Safety outcomes were analysed in patients who had received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT02970305, and is complete. FINDINGS: Between Nov 4, 2016, and April 16, 2019, we randomly assigned 403 patients to pimavanserin (n=201; 131 [65%] male; 187 [93%] White) or placebo (n=202; 137 [68%] male, 186 (92%) White), of whom 400 were included in the efficacy analysis (199 in the pimavanserin group, 201 in the placebo group). Mean age was 37·7 years (SD 9·4) in the pimavanserin group and 36·7 (9·2) years in the placebo group. The change in total NSA-16 score from baseline to week 26 was significantly improved with pimavanserin (least squares mean -10·4 [SE 0·67]) versus placebo (least squares mean -8·5 [0·67]; p=0·043; effect size: 0·211). The number of patients with treatment-emergent adverse events (TEAEs) was similar between groups: 80 (40%) patients experienced TEAEs in the pimavanserin group and 71 (35%) in the placebo group. Most TEAEs were headache (6% [n=13] vs 5% [n=10]) and somnolence (5% [n=11] vs 5% [n=10]). One patient from the placebo group reported severe headache (0·5%), rhinorrhoea (0·5%), cough (0·5%), and influenza (0·5%). In the pimavanserin group, one patient reported severe toothache (0·5%), and two patients had worsening of schizophrenia (1%). Mean change in QTcF interval was higher with pimavanerin (4·5 ms [SD 18·0]) than with placebo (0·0 ms [16·0]). INTERPRETATION: Stable patients with predominant negative symptoms of schizophrenia showed a reduction in negative symptoms after treatment with pimavanserin. However, given the small effect size, further investigation with optimised dosing is warranted to determine the clinical significance of this effect. FUNDING: Acadia Pharmaceuticals.

Long-term evaluation of open-label pimavanserin safety and tolerability in Parkinson's disease psychosis.

INTRODUCTION: Pimavanserin is a selective 5-HT2A inverse agonist/antagonist approved for treating hallucinations and delusions associated with Parkinson's disease psychosis (PDP). Results from short-term, placebo-controlled studies demonstrated a positive benefit/risk profile. This multi-year, open-label study assessed long-term safety and tolerability of pimavanserin. METHODS: This was an open-label extension (OLE) study in patients previously completing a double-blind, placebo-controlled study or a previous OLE study. Safety was evaluated from adverse events (AEs), clinical laboratory results, motor symptoms, electrocardiograms (ECG), and mortality. Durability of response was assessed from the Clinical Global Impression-Severity (CGI-S) scale and Caregiver Burden Scale (CBS). RESULTS: Of 459 participants treated in this OLE study (average age 71.2 years), the median duration of treatment was 454 days. Over the entire study period (approximately 11 years), ≥1 AE occurred in 392 (85.4%) patients; the majority were of mild to moderate intensity, with fall (32.0%), urinary tract infection (19.0%), and hallucination (13.7%) most common. Serious AEs occurred in 188 (41.0%) patients, and an AE leading to study termination or dose discontinuation occurred in 133 (29.0%) patients. Sixty-one patients died, 59 (12.9%) during treatment or within 30 days after the last dose of study drug; the observed mortality rate was 6.45 per 100 patient-years of exposure. Mean scores for the CGI-S scale and CBS generally remained stable for up to 192 weeks (>3.5 years). CONCLUSIONS: Long-term treatment with pimavanserin 34 mg once daily demonstrated a favorable benefit/risk profile with no unexpected safety concerns. Mortality rates suggested no increased risk following long-term treatment.