Dexpramipexole Dose-Ranging Biomarker Study in Subjects With Eosinophilic Asthma

A Randomized, Double-Blind, Placebo-Controlled Dose-Ranging Biomarker Study of the Effects of Dexpramipexole on Eosinophils in Subjects With Eosinophilic Asthma

This is a randomized, double-blind, placebo-controlled, parallel-group, dose-ranging, multi-center study to evaluate the clinical effects of oral administration of dexpramipexole for 12 weeks on peripheral blood eosinophil count in subjects with eosinophilic asthma.

One hundred subjects will receive study drug or matching placebo over 12 weeks of consecutive dosing. Following a short Run-in Period, eligible subjects will enter the Primary Assessment Period and receive twice-daily dosing of study drug or placebo for 12 weeks. Following 12 weeks of treatment, subjects will enter a 12-week Eosinophil Recovery Period. The primary endpoint for the study is the change in blood absolute eosinophil count from Baseline to Week 12.

Inclusion Criteria:

• Male or female ≥18 and <75 years of age at the time of consent
• Physician diagnosis of asthma for ≥12 months (relative to Baseline) based on Global Initiative for Asthma (GINA) 2018 Guidelines
• Asthma requiring treatment with, at a minimum, low dose inhaled corticosteroids in combination with a long-acting β2 agonist, on a stable dose for at least 1 month before Screening
• Bronchodilator reversibility, as evidenced by ≥12% and ≥200 mL improvement in FEV1 15 to 25 minutes following inhalation of albuterol at Screening
• Pre-bronchodilator FEV1 ≥40% and <80% of predicted at Screening and Baseline
• AEC ≥0.30 x10^9/L at the Screening visit
• ACQ-7 ≥1.5 at Screening
• Negative pregnancy test at Baseline
• Adherence ≥85% with twice-daily placebo taken during the Run-in Period

Exclusion Criteria:

• Treatment for an asthma exacerbation within 8 weeks prior to Baseline visit
• Treatment with systemic corticosteroids in the 8 weeks prior to Screening
• Treatment with monoclonal antibody therapy, within 5-half-lives prior to Baseline
• Treatment with selected drugs known to have a substantial risk of neutropenia
• Absolute neutrophil count <2.0x10^9/L at Screening, or any documented history of absolute neutrophil count <2.0x10^9/L.
• Renal dysfunction, defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73m^2 at Screening
• Clinically significant abnormal laboratory or ECG values
• Other medically significant illness
• Use of any smoke or inhaled nicotine delivery device within 1 year prior to Screening
• Pregnant women or women breastfeeding
• Currently taking pramipexole or other dopamine agonists