A 12-month, dose-level blinded safety and efficacy study of levodopa inhalation powder (CVT-301, Inbrija) in patients with Parkinson's disease

Abstract

Introduction: CVT-301 (Inbrija®) is a levodopa inhalation powder for on-demand treatment of OFF episodes in Parkinson's disease patients treated with carbidopa/levodopa. Safety and efficacy results of a 12-month, dose-level blinded extension study of a phase 3 trial (SPAN℠-PD) of CVT-301 are presented.

Methods: Patients were receiving oral carbidopa/levodopa and adjunctive CVT-301 treatment, blinded to dose (60 mg or 84 mg, N = 325). Study visits occurred every 3 months. Pulmonary function was assessed by spirometry. Other safety assessments included dyskinesia and adverse events (AEs). Secondary objectives of the study included maintenance of improvement assessments for occurrence of an ON state during the 60-min post-dose period, change in total daily OFF time, and Patient Global Impression of Change (PGIC).

Results: Most frequent AEs (≥5%) were cough (15.4%), fall (13.1%), upper respiratory tract infection (7.1%), and dyskinesia (5.1%). Severe AEs (>1 event) were cough (1.9%) and dyskinesia (0.6%). Twelve-month mean changes from baseline for FEV₁, FVC, and DL_CO were -0.092 L, -0.097 L, and -0.922 mL/min/mmHg, respectively. At 12 months, 73.0% of patients on 84 mg achieved an ON state within 60 min. Total daily OFF time was reduced by 0.55 h (month 1) and 0.88 h (month 12) for the 84 mg dose. Percentage of patients self-reported as improved by PGIC was 65.5-91.9% over 12 months.

Conclusion: CVT-301 was generally well-tolerated. Twelve-month decline in pulmonary function was consistent with a prior PD control group. Exploratory efficacy results showed CVT-301 maintained improvement at achieving ON states in patients experiencing OFF episodes, decreasing daily OFF time, and maintaining improvement in PGIC.

Keywords: Inbrija; Inhaled levodopa; OFF episodes; Spirometry; Treatment.