FDA-Approved Cancer Medication Stops Parkinson’s Disease Progression in New Study

Written by Partha Nandi, MD, FACP

A drug already approved to treat melanoma can block one of the key steps that lets Parkinson’s disease spread through the brain. That’s the finding from a Johns Hopkins team, and it’s the real science behind the viral claim that a cancer drug can halt Parkinson’s. The result is real and worth understanding. It’s also early, done in mice and in cells rather than in people.

Parkinson’s damage is driven in part by a misfolded protein called alpha-synuclein that travels from one brain cell to the next, seeding more damage as it spreads. The Hopkins researchers showed that two proteins on the surface of brain cells, Aplp1 and Lag3, work together as the doorway that lets those toxic clumps in. Lag3 is also the target of an FDA-approved cancer drug, and that overlap is where the excitement comes from.

I get asked about findings like this in clinic, so let me be straight about it. A treatment that already exists and has a track record in people is a promising place to start. It isn’t a reason to ask for a melanoma drug for Parkinson’s. Here’s what the study actually showed, how the biology works, and what it means for you right now.

Dr. Nandi’s Bottom Line

A cancer immunotherapy that blocks the Lag3 protein stopped toxic alpha-synuclein from spreading and protected brain cells in mice. This is early animal research, not a proven therapy, and the drug isn’t approved or tested for Parkinson’s in people. You can’t act on it at the pharmacy today. What you can do is protect your brain now: move daily, sleep well, eat an anti-inflammatory diet, and see a doctor early about tremor or stiffness.

Two Proteins That Let Parkinson’s Spread Through the Brain

To understand the finding, start with what goes wrong in Parkinson’s. A protein called alpha-synuclein misfolds and clumps together inside brain cells. These clumps, known as Lewy bodies, are a hallmark of the disease, and they don’t stay put. Misfolded alpha-synuclein passes from neuron to neuron, and as it spreads, more cells fill with the toxic clumps and begin to fail. The cells hit hardest are the dopamine-producing neurons in a region called the substantia nigra, which is why movement problems are often the first sign.

The Johns Hopkins team wanted to know how the toxic protein gets inside a healthy neuron in the first place. Earlier work from the same lab had pointed to a surface protein called Lag3 as one entry point, but removing Lag3 only partly stopped the spread, so another player had to be involved. In this study the researchers pinned down that second protein: Aplp1.

Here’s what they found. Aplp1 and Lag3 sit together on the surface of brain cells and act as a pair. In mice engineered to lack both proteins, the amount of harmful alpha-synuclein entering brain cells dropped by about 90 percent. Those mice were also protected where it counts: their dopamine neurons survived, and the movement problems seen in untreated animals didn’t develop. Removing either protein alone helped, but removing both helped far more.

This is animal and cell research, and that’s a real limit on what we can conclude. The results come from mouse models and neurons in a dish, not from people living with Parkinson’s. What the study offers is a clear mechanism and a specific target, which is exactly what you want before testing a treatment.

How a Melanoma Drug Blocks the Spread

So where does the cancer drug come in? Lag3 is better known in cancer care than in brain disease. It sits on immune cells and acts as a brake on the immune response, which is one way tumors slip past the body’s defenses. Block Lag3, and you release that brake so the immune system can go after the cancer.

That’s the thinking behind Opdualag, a combination of two antibodies called nivolumab and relatlimab. The FDA approved it in 2022 for advanced melanoma, and relatlimab is the first approved medicine that blocks Lag3. A drug aimed at this exact protein is already in use in cancer clinics.

The Hopkins researchers used an anti-Lag3 antibody for a different purpose: to break up the partnership between Lag3 and Aplp1 on brain cells. When they did, neurons took in far less toxic alpha-synuclein, its spread slowed, dopamine neurons were spared, and the mice moved better. Blocking the interaction with the antibody worked better than removing Lag3 alone, because Aplp1 stays so closely tied to it.

My take is that this is the practical reason the finding is getting attention. Building a brand-new drug takes many years and often stumbles on safety. An antibody that already carries an FDA approval and a known safety record in people could, in principle, be tested for a new use much sooner. A known target paired with an existing drug is the kind of head start that moves a field forward.

What This Means If You or a Loved One Has Parkinson’s

Let me close the gap between the headline and your life. Opdualag is approved for melanoma, not Parkinson’s. It hasn’t been tested in people with Parkinson’s, the doses and risks for a brain disease are unknown, and Lag3-blocking drugs carry real immune-related side effects. Asking for it off-label wouldn’t be safe or sensible right now. The real next step is testing an anti-Lag3 antibody in animal models of Parkinson’s, then in people, and the Hopkins team has said that’s the direction they’re heading.

Why pay attention at all, then? Because this line of work targets the spread of the disease rather than only its symptoms. Current Parkinson’s medicines help replace the dopamine that’s lost, which eases tremor and stiffness, but they don’t slow the underlying damage. A therapy that stops alpha-synuclein from moving cell to cell could, if it pans out in people, change how fast the disease progresses. That’s a meaningful shift in goal.

There’s also a thread here that I come back to often with patients: where the alpha-synuclein trouble may begin. A growing body of research suggests that for many people, the protein changes can start in the gut years before any movement symptoms appear, then travel up to the brain. That’s one more reason the gut-brain connection deserves your attention, and I’ve written more about how your gut and brain talk to each other.

So what can you do today? Protect the brain cells you have. Regular exercise is one of the most consistently brain-supportive habits we know of. Good sleep helps the brain clear waste. An anti-inflammatory, plant-forward diet supports both gut and brain. None of this is a cure, and none of it replaces your doctor’s care, but these are the levers within reach while the science catches up. For a deeper look at building these habits, see my guide to everyday steps that support a healthier brain.

My Personal RX on Protecting Your Brain as You Age

Protecting your brain isn’t about one miracle pill, and this study is a good reminder of why. The most promising science points to stopping damage early, which is exactly where your daily choices have real power. You can’t change your genes, but you can shape the environment your brain lives in: how you move, what you eat, how you sleep, and how you handle stress. Those inputs influence inflammation, blood flow, and the gut-brain signaling that research increasingly links to long-term brain health.

Think of the tips below as the foundation I come back to with my own patients. None of them replace medical care, and none are a treatment for Parkinson’s or any other disease. They’re simple, repeatable habits that support a healthier brain over time. Here’s where I’d start.

• Move Your Body Most Days: Exercise is the closest thing we have to a brain tune-up. Aerobic activity, strength work, and balance training all support blood flow, mood, and motor control. Aim for something most days, even a brisk walk, and build from there.
• Guard Your Sleep: Deep, regular sleep is when the brain clears metabolic waste. Keep a consistent schedule, wind down without screens, and treat seven to nine hours as a health priority, not a luxury.
• Support Your Gut-Brain Axis: The connection between your gut and brain runs both ways, and a balanced microbiome is part of a healthy brain. I often suggest MindBiotic, a chewable blend of probiotics, prebiotics, and ashwagandha that supports the gut-brain axis along with mood and stress. Tending the gut is one more way to look after the brain upstream of trouble.
• Eat the Rainbow: Colorful plants deliver antioxidants and polyphenols that help the body manage oxidative stress, one of the pressures on aging neurons. Fill your plate with berries, leafy greens, and deeply pigmented vegetables.
• Learn How Your Gut Shapes Your Brain: The more you understand the gut-brain link, the easier these habits are to keep. My book Heal Your Gut, Save Your Brain walks through the science connecting digestion, inflammation, and long-term brain health, with a practical plan you can follow. Knowing the why makes the daily choices stick.
• Cool Down Inflammation: Chronic, low-grade inflammation is hard on brain cells. Favor omega-3-rich fish, olive oil, nuts, and fiber, and go easy on ultra-processed foods and added sugar.
• Keep Challenging Your Mind: Learning keeps neural connections active. Pick up a language, an instrument, or a new skill, and choose activities that stretch you rather than ones you already find easy.
• Manage Stress on Purpose: Ongoing stress raises inflammation and wears on the brain. Build in daily recovery through breathwork, meditation, prayer, or time outdoors, whatever reliably settles your nervous system.
• Stay Connected: Strong relationships and a sense of purpose are linked to better brain aging. Make time for people and for the activities that give your days meaning.
• Don’t Brush Off Early Signs: If you notice a new tremor, stiffness, or slowed movement, bring it to your doctor rather than waiting. Early attention gives you the most options, whatever the cause turns out to be.

When to See a Doctor About Parkinson’s Symptoms

Parkinson’s is easier to manage when it’s caught early, and its first signs are easy to write off as normal aging. One symptom on its own isn’t cause for alarm, but it’s worth a conversation with your doctor if you notice any of the following, especially when they’re new, persistent, or show up on one side of the body:

• A resting tremor in a hand, finger, or limb that appears when the body is still
• Stiffness or rigidity in the arms or legs that doesn’t ease with movement
• Slower movement, smaller handwriting, or a shuffling, less steady walk
• A quieter voice, less facial expression, or reduced arm swing when you walk
• A new loss of smell, acting out dreams during sleep, or ongoing constipation, which can precede movement changes
• Balance trouble or unexplained falls

These signs can have many causes, and most aren’t Parkinson’s. A doctor can help sort out what’s going on and, if needed, refer you to a neurologist. Getting guidance early gives you the most options.

References:

1. Mao, X., Gu, H., Kim, D., Kimura, Y., Wang, N., Xu, E., … Dawson, T. M. (2024). Aplp1 interacts with Lag3 to facilitate transmission of pathologic α-synuclein. Nature Communications, 15, 4663. https://www.nature.com/articles/s41467-024-49016-3
2. Johns Hopkins Medicine. (2024, June 17). New study suggests cancer drug could be used to target protein connection that spurs Parkinson’s disease. ScienceDaily. https://www.sciencedaily.com/releases/2024/06/240617173414.htm
3. National Institute of Neurological Disorders and Stroke. (n.d.). Parkinson’s disease. U.S. Department of Health and Human Services. https://www.ninds.nih.gov/health-information/disorders/parkinsons-disease
4. U.S. Food and Drug Administration. (2022, March 18). FDA approves Opdualag for unresectable or metastatic melanoma. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-opdualag-unresectable-or-metastatic-melanoma
5. National Cancer Institute. (2022, April 6). Opdualag becomes first FDA-approved immunotherapy to target LAG-3.https://www.cancer.gov/news-events/cancer-currents-blog/2022/fda-opdualag-melanoma-lag-3

Frequently Asked Questions

Can I take a cancer drug to treat Parkinson’s disease?

No. The cancer drug in this research, Opdualag, is approved only for melanoma. It hasn’t been tested or approved for Parkinson’s, the right dose and risks for a brain condition are unknown, and it carries serious immune-related side effects. Using it off-label for Parkinson’s wouldn’t be safe. The findings so far are in mice, and human trials would need to come first.

What is alpha-synuclein, and why does it matter in Parkinson’s?

Alpha-synuclein is a protein that normally helps nerve cells communicate. In Parkinson’s it misfolds and clumps into deposits called Lewy bodies. These clumps spread from cell to cell and are linked to the loss of dopamine-producing neurons that drives the movement symptoms of the disease.

What are Aplp1 and Lag3?

They’re two proteins on the surface of brain cells. The Johns Hopkins study found they work together to let neurons absorb toxic alpha-synuclein. Removing both in mice cut that uptake by about 90 percent and protected the animals’ dopamine neurons and movement.

Is this a cure for Parkinson’s?

No. This is early research in mice and cells. It points to a promising target and an existing drug that could be studied, but it isn’t a treatment people can use now. A lot of testing stands between this finding and anything a patient could take.

What can I do now to support my brain health?

Focus on the basics that research consistently links to brain health: regular exercise, good sleep, an anti-inflammatory and plant-forward diet, stress management, and staying socially engaged. See a doctor early if you notice tremor, stiffness, or slowed movement. These steps support your brain but don’t replace medical care.