Influence of disease severity in the efficacy response of Parkinson's disease patients with motor fluctuations: Post-hoc analysis from combined BIPARK-I and II

Abstract

To evaluate the impact of disease severity on the efficacy of opicapone (OPC) in levodopa-treated Parkinson's Disease (PD) patients with motor fluctuations. OPC, a once-daily COMT inhibitor, proved effective in the treatment of motor fluctuations in PD patients in two large, pivotal, multinational trials (BIPARK-I and II) [[1]Ferreira J.J. et al.Lancet Neurol. 2016; 15: 154-165Google Scholar,[2]Lees A.J. et al.JAMA Neurol. 2017; 74: 197-206Google Scholar]. Patient-level data from matching treatment arms in BIPARK-I and II were combined in placebo (PLC) and OPC-50 mg groups. The studies had similar designs (primary efficacy endpoint: change from baseline in patient diaries-based absolute OFF-time) and eligibility criteria [[1]Ferreira J.J. et al.Lancet Neurol. 2016; 15: 154-165Google Scholar,[2]Lees A.J. et al.JAMA Neurol. 2017; 74: 197-206Google Scholar]. An exploratory post-hoc analysis was performed to evaluate the influence of disease severity (assessed by modified Hoehn and Yahr, H&Y <2.5 vs =";≥2.5) on efficacy outcomes (i.e., change from baseline in OFF-/ON-time). Applied linear regression's slope was statistically tested for deviation from zero and linearity. In total, 1027 patients were randomized to BIPARK-I and II and 522 patients took a dose of study medication; Full Analysis Set comprised 517 [PLC (n = 255); OPC-50 mg (n = 262)]. Two PLC patients with H&Y = 4 were excluded from disease severity analysis as there were no OPC-50 mg matched-patients. For OPC-50 mg, OFF-/ON-time magnitude of responses was not influenced (non-significant linear regression). For PLC, the higher H&Y staging at baseline the greater magnitude of OFF-/ON-time response at endpoint (ending in a linear regression slope statistically significant). Disease severity impacted OFF-/ON-time magnitude of responses for PLC but not OPC-50 mg patients in a clinical study setting.