First Parkinson's patient gets a pill meant to clear cells' worn-out parts

A British biotech company has started testing its experimental Parkinson’s pill in people who have the disease. Mission Therapeutics said it has given the first dose of MTX325 to a patient at the Royal Liverpool University Hospital in the UK, the start of a trial that will include 36 people.¹ The company listed the news on its website with a date of 15 October 2026.²

The drug is built around a simple idea. Every cell runs on mitochondria, small structures that make energy, and these wear out over time. Cells have a cleanup routine for the broken ones. MTX325 is meant to speed up that cleanup in the brain.¹ No results from Parkinson’s patients exist yet, and the trial is mainly designed to check whether the drug does in people what it did in the lab.¹

What happened

The trial, called MTX325-101, will enroll 36 people with mild to moderate idiopathic Parkinson’s, meaning Parkinson’s with no known single cause. Sites are in the UK, Europe and Australia, and recruitment is ongoing.¹

This is a Phase 1b trial: an early test in patients, coming before the larger studies needed to show whether a drug helps. Its stated goal is “proof-of-mechanism”, which means checking that the drug acts on its target in the body. Researchers will look at a wide range of biological markers and brain imaging measures, alongside safety and how well people tolerate the drug.¹ The company has said it expects data in the second half of 2027.³

The start came a little later than once planned. In October 2025, the company said the trial was due to start in the first half of 2026.³

How the drug is meant to work

The cell’s process for removing damaged mitochondria is called mitophagy. An enzyme called USP30, found on mitochondria, acts as a brake on this process. MTX325 is a pill designed to reach the brain and block USP30, with the aim of improving the clearance of faulty mitochondria, supporting cell health and reducing inflammation.¹

The reasoning, as Drug Discovery World described it, is that if nerve cells cannot get rid of faulty mitochondria, they start to malfunction and die. A build-up of faulty mitochondria has been linked to several diseases, including Parkinson’s, kidney disease and heart failure.³ Mission says blocking USP30 could slow or stop the processes thought to drive Parkinson’s.¹ That is a hope, not a finding in patients.

The evidence so far

The support for the drug comes from animal studies and early tests in healthy people.

• Mouse studies. A study in Nature Communications found that deleting the gene for USP30 protected dopamine-producing nerve cells in a mouse model of Parkinson’s. Mission says MTX325 produced a similar result in the same model.¹ The work was done with scientists at Cambridge University and Harvard University, according to the company.⁴ These are mouse results and may not carry over to people.
• Company lab data. In its own preclinical studies (tests before human trials), Mission reports more mitophagy and helpful effects on the buildup of alpha-synuclein, a protein that piles up in Parkinson’s, and on the dopamine cells the disease attacks.¹
• Healthy volunteers. An earlier Phase 1a study in healthy people is complete, Mission says. The drug reached the brain and spinal cord in high amounts, and a PET scan study (a type of imaging that tracks where a substance goes) confirmed it spread into brain tissue.¹

When the company first got approval for human testing in 2023, it described a larger plan: a multi-part study of up to 160 adults, both healthy people and those with Parkinson’s, at UK sites.⁴ The sources do not explain how that plan turned into the current separate studies.

What it does not show yet

Nothing so far shows that the drug slows Parkinson’s in people. The new trial is not built to answer that. It asks whether the drug changes biological signs in patients, which is a more modest question than whether patients feel or function better.¹

The trial is also small. Thirty-six patients, a design focused on how the drug acts, and a 2027 readout mean answers about symptoms are still a long way off.¹ Mouse models of Parkinson’s do not capture everything about the human disease, so the step from animal results to patients is a real test.

The company’s executives frame the trial ambitiously. Chief Development Officer Sarah Fritchley said:

Dosing the first Parkinson’s disease patient is a significant milestone in the development of MTX325, a potential disease-modifying treatment for this serious neurodegenerative disease, which affects almost one million people in the US and 1.2 million in Europe.

¹

Chief Medical Officer Suhail Nurbhai said the drug “has the potential to change the course of treatment for patients with Parkinson’s disease – moving beyond management of symptoms offered by current therapies.”¹ These are statements of goals by the company, not results.

Who is behind it

Mission Therapeutics is based in the UK. It is backed by investors including Pfizer Venture Investments, Sofinnova Partners, Roche Venture Fund, SR One, IP Group and Rosetta Capital, and it reports patent protection on the MTX325 molecule through 2041.¹

In October 2025, the company raised $13.3 million to run this patient trial. The program is also supported by a $5.2 million grant from the Michael J. Fox Foundation and Parkinson’s UK, and the UK medicines regulator, the MHRA, approved the trial.³

The company has other ties in the field. It says it collaborates with AbbVie on research into related enzyme-blocking drugs for Alzheimer’s and Parkinson’s, and has an evaluation and option agreement with Pfizer. In July 2026 it announced a deal worth up to $292 million with Dimerix for a sister drug, MTX652, aimed at sudden kidney injury, and said it was sharpening its focus on brain diseases.²

How it fits the field

Many Parkinson’s drugs today manage symptoms. The company’s scientific chief said in 2023 that there were no approved treatments that change the underlying disease.⁴ That gap is why several groups are testing drugs aimed at the biology behind the disease. Biohack recently covered a different approach, an inflammation pill tested in early Parkinson’s.

The trial also matters to people interested in aging more broadly. Decline of mitochondria is widely studied as one of the changes that come with age, and Parkinson’s is one of the diseases where it is suspected to play a role. If helping cells clear worn-down parts turns out to help nerve cells, the same idea could be tested in other age-related conditions.¹ Mission itself has listed several diseases where it believes faulty mitochondria play a part, including heart failure and Alzheimer’s.⁴

What to watch next

• Progress on enrolling all 36 patients across the UK, Europe and Australia.¹
• Whether safety holds up in people with Parkinson’s, not only in healthy volunteers.
• The proof-of-mechanism data expected in late 2027, showing whether the drug changes the biological markers and imaging measures it is designed to affect.¹³
• Whether the company moves on to larger trials that test effects on symptoms and disease progression.