Clinical trial seeks the impact of hypertension medication on early-stage Parkinson's

International research examining a novel mechanism to treat Parkinson's disease is underway at The Ohio State University Wexner Medical Center's Madden Center for Parkinson's Disease and Related Disorders.

The Safety, Tolerability, and efficacy Assessment of Isradipine for PD clinical trial, known as STEADY-PD III, will determine whether the calcium channel blocker isradipine can slow disease progression in patients with early-stage Parkinson's.

The trial is funded by the National Institute of Neurological Disorders and Stroke. The randomized, double-blind, placebo-controlled phase 3 trial will enroll 336 patients and follow them up for 36 months with at least 12 in-person visits and four phone calls.

"The idea is we really want to see if [isradipine] is disease-modifying, so we need a little bit more time to assess that," says Ariane Park, MD, MPH, clinical assistant professor of neurology.

Isradipine is readily available because it's approved by the U.S. Food and Drug Administration as an antihypertensive medication.

It's a promising agent to treat Parkinson's disease because it blocks the CAv1.3 L-type calcium channel, which maintains a rhythmic pacemaking that the brain's dopamine neurons rely on to help coordinate movement. But because the process is very energy demanding, it's believed to accelerate the degeneration of dopamine neurons that often trigger Parkinson's symptoms.

The Madden Center has four patients enrolled in STEADY-PD III and Parks says patients are enthusiastic to join.

"When they have very mild symptoms and they don’t need medicines, a lot of people are excited about it," she says.

Investigators will use the Unified Parkinson Disease Rating Scale to measure study participants' progress. The primary outcome is change in total UPDRS score from baseline to 36 months in the "on state," when medications are working well and symptoms are reduced. Results are expected 2019.