Phase III Clinical Trial to Evaluate Calcium Channel Blocker for Parkinson’s

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Researchers at the University of California, San Diego School of Medicine have launched a Phase III clinical trial to evaluate the drug isradipine, a calcium channel blocker often used to treat high blood pressure, as a potential new treatment for Parkinson disease (PD). The goal of the study is to determine whether the drug can slow the progression of the disease by keeping the brain’s dopamine-producing cells healthier for a longer period of time.

Irene Litvan, MD, director, Movement Disorder Center at UC San Diego Health System.

“Isradipine has been demonstrated to be safe and tolerable in patients with Parkinson’s disease,” said Irene Litvan, MD, site investigator and director of the Movement Disorder Center at UC San Diego Health System. “This new study will determine whether the drug can be effective in slowing the progression of the disease and could, thereby, complement existing symptomatic treatments to improve the quality of life of individuals with the disease.”

PD is a progressive neurological disorder that affects an individual’s speed and amplitude of movements and decreases the speech volume.  Patients with PD experience stiffness or rigidity of the arms and legs and walking difficulties in addition to tremors in their hands, arms, legs or jaw. Patients with PD also experience vivid dreams, depression, and constipation. 

Isradipine is a Food and Drug Administration-approved drug to treat high blood pressure. Prior population studies have shown that people taking isradipine for high blood pressure have a lower incidence of PD. Additionally, isradipine is in a category of drugs called calcium channel blockers, meaning they inhibit certain cellular functions. Overactive calcium channels may play a role in the death of the dopamine producing cells in the brain that is one of the hallmarks of PD.

A Phase II evaluation of isradipine, which was conducted to determine the safety and appropriate dosage for the drug, was completed in 2012. The study was funded by a $2.1 million grant from The Michael J. Fox Foundation for Parkinson’s Research (MJFF), which also supported preclinical research into the effects of isradipine on Parkinson’s progression by D. James Surmeier, PhD, of Northwestern University.

The study, called STEADY-PD, is sponsored by the Parkinson Study Group and is co-lead by the University of Rochester Medical Center (URMC) and Northwestern University. UC San Diego Health System is one of the national research participants.

Patients who are eligible for the clinical trial will have been diagnosed with PD for less than 3 years and are not currently on any dopaminergic therapy such as levodopa, dopamine agonist, or MAO-B inhibitors.

“If it proves to be effective, this drug will change the way we treat Parkinson’s disease, and the major advantage of it is that isradipine is already widely available, inexpensive and will allow for rapid translation of our research into clinical practice,” said Tanya Simuni, MD, principal investigator of the study and professor of neurology at Northwestern University Feinberg School of Medicine. “Although we now have very effective symptomatic treatments to manage Parkinson’s, the development of a disease-modifying intervention remains the Holy Grail.”

Patients with PD are advised not to take this medication if they are not part of this therapeutic clinical trial.

For additional information about this clinical trial, please contact the UC San Diego Health System site coordinator at 858-822-5751 or rellam@ucsd.edu