Harshi Peiris, Ph.D.

Japan just approved putting new brain cells into people with Parkinson's.

That has never happened anywhere before.

Every Parkinson's drug today tops up or mimics dopamine. None of them replace the cells the disease destroys.

This one does.

Only 7 patients. Conditional approval. Early.

But for the first time, someone is putting back what Parkinson's takes away.

Japan has conditionally approved the first stem cell treatment that puts new senders/cells into the brain.

The US has one in Phase 3, and at least six more are in trials worldwide. I break down every one, what it costs, who can get it, and what to ask your doctor first:

youtu.be/M-CCd-0IBlg?si… via @YouTube

The GLP-1 and dementia story may come down to timing.
Before symptoms, these drugs may help by improving diabetes, weight, blood pressure and sleep, which all feed into brain health. Once Alzheimer’s has started, the big trials haven’t shown benefit. That’s one explanation, not the only one.

Results are also averages, so some people may respond well and others not at all, but we can’t tell who without better biomarkers, especially ones that show the drug reached the brain.
@ScienceMagazine
x.com/Neuroscope_mp/…

Levodopa doesn't stop working in Parkinson's.

It wears off faster.

Here's why: your brain has dopamine senders and receivers. Parkinson's kills the senders. The receivers are still there, waiting.

Levodopa works through the senders that are left. Fewer senders, less storage, shorter doses.

Every medicine today works around that loss. Stem cells are the first attempt to replace it.

For over a decade, every drug tested in primary progressive MS failed, except Ocrevus, an infusion.

Now a daily pill, fenebrutinib, has matched it head to head in a Phase 3 trial.
The catch is the liver, and the FDA decides next year. 🧵