Integrated Analysis of Droxidopa for the Treatment of Neurogenic Orthostatic Hypotension in Patients with Parkinson Disease

Introduction: Neurogenic orthostatic hypotension (nOH) is associated with neurodegenerative conditions, may cause symptoms of end-organ hypoperfusion, increases fall risk, and can negatively impact quality of life. Droxidopa is approved for the treatment of symptomatic nOH in adults. As the largest subpopulation of patients with nOH has a diagnosis of Parkinson disease (PD), the efficacy and tolerability of droxidopa in patients with PD and nOH were examined using integrated clinical trial data. Methods: Post hoc analyses included data from the phase 3, randomized, placebo-controlled clinical trials of droxidopa (two short-term [1−2 weeks] trials and one medium-term [8−10 weeks] trial) in the subset of participants with PD and symptomatic nOH. Efficacy was assessed using standing blood pressure (BP) measurements and the Orthostatic Hypotension Questionnaire (OHQ), a patient-reported evaluation of nOH symptoms (Orthostatic Hypotension Symptom Assessment [OHSA]), and their impact (Orthostatic Hypotension Daily Activity Scale [OHDAS]). Results: The analysis included 307 patients with PD (droxidopa, n = 150; placebo, n = 157). Compared with placebo, droxidopa significantly improved the OHQ composite score (P = 0.014), the OHSA composite score (P = 0.022), and the OHDAS composite score (P = 0.029) from baseline to end of study/week one. We found significant increases in standing mean systolic/diastolic BP for droxidopa versus placebo (P = 0.003/0.002). Adverse event (AE) rates were qualitatively similar between groups; the most frequently reported AEs in the droxidopa groups included headache, dizziness, nausea, and hypertension. Conclusions: These post hoc analyses suggest that droxidopa provides meaningful clinical benefits and is well tolerated in the treatment of symptomatic nOH in patients with PD.