Drug Could Slow Progression of Parkinson's

A new drug could help slow the progression of Parkinson’s disease, according to researchers in Atlanta.

A team at Emory University showed the anti-inflammatory drug known as XPro1595 was able to protect neurons and therefore reduced motor deficits in rats. The drug was injected subcutaneously, which differed from prior experiments where it was injected directly into the brain. The results of the study were published in the Journal of Parkinson’s Disease.

The discovery could go a long way in helping patients deal with some of the most difficult complications of Parkinson’s, according to a statement from the school.

“This is an important step forward for anti-inflammatory therapies for Parkinson’s disease,” said Malu Tansey, PhD, associate professor of physiology at the Emory University School of Medicine. “Our results provide a compelling rationale for moving toward a clinical trial in early Parkinson’s disease patients.”

The drug specifically targets a soluble form of tumor necrosis factor (TNF), described as an inflammatory signaling molecule. According to the Emory team, the specified the target to avoid compromising immunity to infections, which is a known side effect of existing anti-TNF drugs used to treat disorders.

“Inflammation is probably not the initiating event in Parkinson’s disease, but it is important for the neurodegeneration that follows,” Tansey said. “That’s why we believe that an anti-inflammatory agent, such as the one that counteracts soluble TNF, could substantially slow the progression of the disease.”

The researchers injected neurotoxin 6-hydroxydopamine (6-OHDA) into one side of a mouse’s brain. As a result, the neurons that would produce dopamine in the animal’s brain died and caused impaired movement.

Three days after that injection, the mice were then given XPro1595 and, as a result, just 15% of the dopamine-producing neurons had died 5 weeks later. In the group that did not receive the medication, 55% of the neurons had died.

The study results also found that the drug helped reduce motor impairment and that the degree of dopamine loss was connected to the “degree of motor impairment and immune cell activation,” according to Emory.

When the drug was administered 2 weeks after injection, the team reported 44% of the vulnerable neurons were lost, “suggesting that there is a limited window of opportunity to intervene.” For humans, that window between diagnoses and the time when the most neurons are lost is between 4 and 5 years, according to Tansey.

“If this is true, and if inflammation is playing a key role during this window, then we might be able to slow or halt the progression of Parkinson’s with a treatment like XPro1595,” she said.

Research for the study was funded by the Michael J. Fox Foundation for Parkinson’s Research.

“We are proud to have supported this work and glad to see positive pre-clinical results,” Marco Baptista, PhD, the foundation’s associate director of research programs, said in a statement. “A therapy that could slow Parkinson’s progression would be a game changer for the millions living with the disease and this study is a step in that direction.”

The drug is licensed by FPRT Bio, which is seeking a full clinical trial for treatment of the disease. Emory also announced that Tansey and Yoland Smith, PhD, from the Yerkes National Primate Research Center, received a grant to test the drug in a non-human primate model of the disease.

Tansey is a former employee of Xencor, which developed the technology as well as the drug used in the study, but she has no significant stake in the company. R.J. Tesi, chief executive officer of FPRT Bio, was a co-author of the paper.