The movie “Awakenings” aside, there’s no really good treatment for the half a million Americans living with Parkinson’s disease.
Dopamine-replacing drugs often help control the movement disorders that are the hallmark of the disease.
But they don’t work for all patients, and they don’t bring any relief from the cognitive effects of the disease — in fact, they often make them worse.
That’s why there’s a lot of excitement about a small study using nilotinib (Tasigna) to treat Parkinson’s disease.
The drug, approved by the Food and Drug Administration (FDA) to treat cancer, suppresses tumor growth by spurring cells to do some housecleaning.
In high doses, it is a heavy-hitting chemotherapy drug that cleans the cells right out of existence.
In lower doses, it seems to cause brain cells to clear out the buildup of unhealthy proteins that interfere with normal functioning.
How It Helps with Parkinson’s
In Parkinson’s disease, a protein called alpha-Synuclein chokes off the cells that produce dopamine. As less and less dopamine is produced, the patient’s symptoms get worse.
Dr. Charbel Moussa, Ph.D., a medical researcher at the Movement Disorders Program at Georgetown University Medical Center, presented at a medical conference his first findings with human patients after eight years of research into using the drug for Parkinson’s disease.
Although just 12 patients participated in the trial, Moussa and his peers are excited because the drug seemed to reverse Parkinson’s symptoms, not just slow their progression.
The study participants had Parkinson’s disease with symptoms of dementia or Lewy Body dementia, which Moussa described as a combination of Parkinson’s and Alzheimer’s.
Though primarily testing nilotinib for safety, Moussa found that the levels of alpha-Synuclein dropped in patients’ spinal fluid, and the levels of dopamine they produced naturally rose. The patients scored higher on measures of movement and cognitive ability at the end of the study.
“With the current standard of care, when you improve motor skills you worsen cognitive skills. With this drug what was seen was a very, very significant improvement in both motor and cognitive skills at the same time,” Moussa told Healthline.
Parkinson’s specialists who weren’t involved in the study cautioned that other drugs have looked promising early on only to show no benefits in larger clinical trials. But they agreed the drug seems to accomplish something that no previous candidates have.
“If it really works it could be an amazing big deal,” said Dr. Caroline Tanner, Ph.D., the director of Parkinson's Disease Research, Education and Clinical Center at the San Francisco Veteran's Affairs Medical Center.
Dr. Michael Okun, the national medical director of the National Parkinson Foundation and a professor at the University of Florida College of Medicine, said that if the drug holds up in bigger trials, it could be prescribed for patients quickly because it’s already FDA approved.
Even so, what’s considered safe enough for a chemotherapy drug may have unacceptable side effects for Parkinson’s patients, who could take it for many years, Tanner said.
Moussa was confident that the lower dose eliminates the side effects seen at chemotherapy doses. There were no adverse events in the six-month study.
Drug Could Also Work for Alzheimer’s
But the real bombshell of Moussa’s research may have nothing to do with Parkinson’s disease.
Nilotinib forces brain cells to clear out protein buildup, which means it could also treat Alzheimer’s disease. Alzheimer’s is roughly 10 times more common than Parkinson’s disease.
In Moussa’s earlier studies on mice, nilotinib cleared out the tau and beta amyloid proteins linked to that brain disease. In the human patients, cerebral spinal fluid showed drops in levels not just of alpha-Synuclein but also of tau and beta amyloid.
“Even if it turns out that this drug by itself is too toxic,” Tanner said, “the fact that you can target this protein pathway and make alterations in people with Parkinson’s disease or dementia is earthshaking.”
The current study was funded by patient activism, Moussa said. But he’s hoping that its results will inspire Novartis, which makes nilotinib, to fund larger clinical trials. Drug companies generally fund the studies required by the FDA as part of the drug approval process.