Use of the Modified Functional Status Questionnaire to Assess Functioning in Patients with Parkinson’s Disease Psychosis Treated with Pimavanserin
Authors: Evidente Virgilio G. H. , Chrones Lambros , Revankar Ratna , Doshi Dilesh , Abler Victor , Rashid Nazia 
Published: January 2025

Introduction

Patient-reported outcomes (PROs) are increasingly collected in clinical trials and real-world studies as they provide valuable information on the impact of a treatment from the patient’s perspective. Studies in Parkinson’s disease psychosis (PDP) have focused on hallucination and delusions, however individuals with PDP also face functional limitations associated with worsening psychosis. Assessing activities of daily living (ADLs) and functioning of PDP patients can help inform PDP treatment. The International Parkinson and Movement Disorder Society has recommended the use of the Functional Status Questionnaire (FSQ) which has been infrequently utilized. Prior results were reported from a Phase 4 open-label study examining the impact of pimavanserin on ADLs and functioning in patients with PDP which utilized a modified version of the FSQ (mFSQ) as the primary outcome measure. In this analysis, we provide additional data on the patient-reported mFSQ within specific domains and correlation to the Schwab & England ADL scale.

Methods

Eligible patients entered a 16-week single-arm, open-label study of once-daily oral pimvanserin (34mg). The 6 domain FSQ was modified to assess 5 domains by removing the work/performance domain since this was not applicable to the patients in this study. The mean change from baseline to week 16 was evaluated in mFSQ domains (Basic ADL, Intermediate ADL, Psychological Function, Quality of Interaction, Social Activity). In addition, correlation between Schwab & England ADL scale and observed mFSQ value across post-Baseline visits were evaluated.

Results

A total of 29 patients were enrolled in the study, mean age (70.2 years), 62% males. The MMRM LSM (SE) for mSFQ from baseline to Week 16 were the following within each domain: Basic ADL (n=22), 8.1 (2.41), p=0.0031; Intermediate ADL (n=21), 7.0 (3.00), p=0.0286; Psychological Function (n=22), 13.3 (1.94), p <.0001; Quality of Interaction (n=22), 12.3(2.07), p <.0001; and Social Activity (n=18), 25.8 (7.52), p=0.0026. All mFSQ domains were showing improvement at 16 weeks from baseline; however, the largest change was seen in Social Activity. The correlation of mFSQ and the Schwab & England ADL scales resulted in a correlation coefficient of r=0.6 (p <.0001) for patient total score and r=0.5 (p<.0001) for caregiver total score. There was a consistent trend among both scales which was demonstrating improvement among patients and caregivers.

Conclusions

This was the first open-label clinical trial to utilize the mFSQ in patients with PDP. In this small, proof-of-concept study, treatment with pimavanserin was associated with improvement across all mFSQ domains; most improvement was seen in social activity. Additionally, the mFSQ was significantly correlated with the Schwab & England ADL, thus this appears to be a promising scale deserving of further evaluation and use in clinical studies as well as in the clinic to complement other assessments.

Funding

Acadia Pharmaceuticals, Inc.