Results out of a study funded by The Michael J. Fox Foundation for Parkinson's Research (MJFF) have enabled researchers to secure a $23 million grant from the National Institutes of Health (NIH), continuing a repurposed drug approved for hypertension to Phase III testing for slowing Parkinson's progression. The trial investigating the compound isradipine will be the most advanced, current study into a disease-modifying therapy for Parkinson's, an unmet need.
Isradipine is a calcium channel blocker prescribed to treat high blood pressure. Epidemiological data from population-scale studies note a lower incidence of Parkinson's disease (PD) among people who take this drug. Furthering PD researchers' interest, laboratory tests have shown that blocking calcium channels protects dopamine neurons, degeneration of which is one of the hallmarks of Parkinson's disease.
"What the millions living with Parkinson's disease need is a drug that will halt or slow the progression of their disease," said Todd Sherer, PhD, CEO of MJFF. "We've invested in isradipine, and we're glad to see it moving forward with NIH support, because it has shown such potential to do just that."
Early Investment Secures Follow-on Funding
The NIH funding will move the Safety, Tolerability and Efficacy Assessment of Dynacirc® for PD (STEADY-PD) study into Phase III efficacy testing. Dynacirc® is the commercial name of the isradipine hypertension drug. Principal investigator Tanya Simuni, MD, director of the Parkinson's and Movement Disorders Program at Northwestern University, and the Parkinson Study Group hope to enroll more than 300 participants at 56 clinical sites throughout North America.
MJFF began funding isradipine research in 2007 with support for a project from D. James Surmeier, PhD, also of Northwestern University, looking at the compound's neuroprotective effects in PD models. The NIH also funded Surmeier's pre-clinical work into this compound.
In 2008, the Foundation granted STEADY-PD $2.1 million for the Phase II clinical trial, and researchers published results in September 2013 in the Movement Disorders journal showing that isradipine is safe and tolerable in Parkinson's patients. They also determined the maximal, tolerable dosage (10 mg daily).
Millions Have Critical Need for Better Therapy
Drug repurposing -- studying a small molecule or compound approved to treat one disease for its effect on another -- speeds a drug into clinical trials and hastens approval from the U.S. Food and Drug Administration because detailed information on its pharmacology, formulation and safety is already available and has been reviewed.
This urgency is of particular importance for the one million Americans living with Parkinson's and, with a growing U.S. population of older adults, the many more who may age into the disease in the near future. Parkinson's disease is a progressive, neurological disorder that leads to motor symptoms such as tremor and rigidity and non-motor symptoms, including depression and cognitive decline.
Current PD therapies treat the symptoms of the disease, but do not slow its progression. Furthermore, their timeframe of efficacy is limited and PD medications can elicit their own serious side effects.
"We're all after the same goals -- a cure for Parkinson's and better quality of life for those living with this disease," said Story Landis, PhD, director of the National Institute of Neurological Disorders and Stroke, which granted STEADY-PD the Phase III funding. "We can work together to move promising research forward and make a difference in patients' lives."