Mentara Therapeutics Launches to Advance MTA-304, a Phase 2-Ready PDE10A Inhibitor, for Levodopa-Induced Dyskinesia in Parkinson's Disease

-SPRIM Global Investments-backed company acquires asset from EuMentis Therapeutics-

- Phase 2 study planned for first half of 2027-

SAN DIEGO and SYDNEY, Oct. 7, 2026 /PRNewswire/ -- Mentara Therapeutics, a new neuropsychiatry company backed by SPRIM Global Investments, today launched with the acquisition of EM-221, now MTA-304, from EuMentis Therapeutics. MTA-304 is a highly selective, second-generation PDE10A inhibitor, and Mentara will take it into a Phase 2 study in levodopa-induced dyskinesia (LID) starting in the first half of 2027.

Levodopa is still the most effective treatment for Parkinson's disease. However, 40–50% of patients on long-term therapy develop dyskinesia (involuntary, uncontrolled movements) within four to six years. Treatment options are limited, and amantadine extended release (ER) is currently the only FDA-approved therapy for LID. Amantadine ER's side effects, such as hallucinations, dizziness and swelling, can limit its use, so patients and doctors are often forced to choose between controlling Parkinson's symptoms and living with disabling dyskinesia.

MTA-304 has completed three Phase 1 studies in 86 subjects, which showed a favorable safety and tolerability profile. In a non-human primate model of LID, MTA-304 reduced dyskinesia by 40% without reducing levodopa's benefit. In a rat model, it outperformed amantadine.

"People with Parkinson's shouldn't have to trade symptom control for dyskinesia," said Frank Stonebanks, CEO of Mentara Therapeutics. "MTA-304 has a clean Phase 1 package and strong preclinical data in LID. With a dedicated company and initial investors behind it, we can move quickly to answer the question that matters to patients in Phase 2."

"We are thrilled to back Mentara Therapeutics," said Dr. Michael Shleifer, Co-Founder and Managing Partner, SPRIM Global Investments. "They have the right people and the right product at the right time."

Mr. Stonebanks led EuMentis as CEO for the past 18 months and has more than 25 years of experience in biotech operations and venture capital. He was previously Chairman and CEO of Renibus Therapeutics, where he raised more than $140 million, took the lead program into Phase 3 and acquired Phase 3 ready veverimer. He also founded and was CEO of Triphase, which was acquired by Celgene (BMS).                   

Mr. Stonebanks also held leadership roles at JJDC (J&J's investing unit, including as a co-founder of J&J Internal Ventures, now J&J Innovation), IBM Ventures, Lumira Ventures and Novaquest Capital Management.

Under the agreement, EuMentis shareholders will become shareholders in Mentara. Financial terms were not disclosed.

About MTA-304
MTA-304 (formerly EM-221) is an investigational, highly selective, second-generation PDE10A inhibitor originally discovered by Mochida Pharmaceutical Co., Ltd. PDE10A is an enzyme found almost exclusively in the striatum, the brain region where levodopa-induced dyskinesia originates. By blocking it, MTA-304 is designed to rebalance the striatal signaling pathways that levodopa overstimulates, reducing dyskinesia without weakening levodopa's benefit.

About Mentara Therapeutics
Headquartered in Sydney, Australia, Mentara Therapeutics is focused on improving the health and well-being of all people affected by neuropsychiatric disorders. www.mentaratherapeutics.com 

About SPRIM Global Investments
Headquartered in Singapore, SPRIM Global Investments is a privately held life sciences venture capital firm founded in 2008 that specializes in clinical-stage therapeutics, digital health and R&D infrastructure. www.sprim.net 

About EuMentis Therapeutics
EuMentis Therapeutics was a San Diego-based clinical-stage biotech company. It licensed EM-221 from Mochida Pharmaceutical Co., Ltd. of Japan after three Phase 1 studies had been completed and advanced the program toward Phase 2 development. EuMentis has been wound down now that the transaction has closed.

Media Contact
Media: Amy Conrad
Juniper Point
[email protected] 

Company: Mentara Therapeutics
www.mentaratherapeutics.com
[email protected]

SOURCE Mentara Therapeutics