Promising results from study of type 2 diabetes drug in treatment of Parkinson’s disease

Evidence continues to mount that a newer class of anti-diabetic drugs called incretin mimetics, or glucagon-like peptide-1 receptor agonists, could slow or stop progression of Parkinson’s disease. However, scientists caution that more research is needed to determine if these drugs are safe and effective in people with Parkinson’s.

The latest news comes from a recent clinical trial in the United Kingdom, in which some people with Parkinson’s retained more motor function after taking exenatide for 48 weeks than patients who took a placebo. Even three months after stopping exenatide therapy, treated patients retained higher motor function than the control group.

“As always with studies on small numbers of patients, we have to view these results with caution, but they could signal a turning point in Parkinson’s treatment,” says Patrik Brundin, M.D., Ph.D., director of Van Andel Research Institute’s Center for Neurodegenerative Science and chairman of The Cure Parkinson’s Trust’s Linked Clinical Trials Committee (LCT), which annually reviews several drugs that could be repurposed from other diseases to treat Parkinson’s. “The careful scientific review conducted by LCT is instrumental in finding existing drugs suitable for Parkinson’s.”

In 2012, LCT prioritized a slow-release version of exenatide as a top candidate for clinical evaluation. Successes in recent trials validate LCT’s potential to bring new therapies and hope for the 10 million people worldwide who are living with Parkinson’s.

Researchers led by neurologist Thomas Foltynie, Ph.D., M.B.B.S., at University College London conducted the study in partnership with The Cure Parkinson’s Trust, a British nonprofit organization dedicated to finding a cure for Parkinson’s disease; The Michael J. Fox Foundation for Parkinson’s Research, which funded the trial; and AstraZeneca, which provided the drug and placebo.

Efforts are already underway to launch a larger, multi-center trial to determine whether exenatide could be used as a treatment to slow disease progression.

Despite their enthusiasm, study organizers caution against starting treatment with exenatide before researchers and physicians better understand how well these drugs work and whether there are any unexpected long-term side effects.

“These results are definitely promising, but we need much more research and larger clinical trials to evaluate the extent of exenatide’s effects and whether it is safe for patients with Parkinson’s to take for longer periods of time,” says Brundin.

“These results are definitely promising, but we need much more research and larger clinical trials to evaluate the extent of exenatide’s effects and whether it is safe for patients with Parkinson’s to take for longer periods of time.” –Dr. Brundin

“Studies in the laboratory have been telling us for years that failures in cellular metabolism may be at least partially responsible for why brain cells die in Parkinson’s disease,” says Brundin. “Additionally, we observe connections between impaired energy metabolism and the ability of brain cells to handle the protein alpha-synuclein that is prone to accumulate in Parkinson’s.”

For these reasons and more, leadership of the Linked Clinical Trials Committee have prioritized several type-2 diabetes drugs, including exenatide, for potential treatment of Parkinson’s disease.

The latest study involved 60 patients with Parkinson’s disease, 30 of whom received weekly exenatide injections and 30 of whom received a placebo. The complete study record is available on clinicaltrials.gov.

“Studies like this provide hope and suggest that we are closer than ever to a drug that actually might slow the progression of Parkinson’s disease,” says Brundin. “We are cautiously optimistic, but urge clinicians and patients to wait to add drugs such as exenatide to treatment regimens until they are proven safe and effective in Parkinson’s.”

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