Merck Halts Phase 2 Trial of Neuphoria Therapeutics' Alzheimer's Drug Candidate 'MK-1167'
Reasons for Clinical Trial Discontinuation and Drug Information
Merck & Co. (MRK) has discontinued the Phase 2 trial (NCT06721156) of 'MK-1167', an Alzheimer's disease drug candidate developed in collaboration with Neuphoria Therapeutics (NEUP). The decision was made following an interim analysis that revealed a lack of efficacy. No safety issues were reported. MK-1167, which has not yet been assigned a brand name or generic name, is a small molecule positive allosteric modulator (PAM) that targets the alpha-7 nicotinic acetylcholine receptor (alpha-7 nAChR). It was being co-administered with acetylcholinesterase inhibitors, the current standard of care, in a trial involving 349 patients, but failed to demonstrate efficacy in improving cognitive function.
Financial Implications and Impact on Partnership
This failure is expected to have a significant financial impact on Neuphoria. The two companies entered into a licensing agreement in 2014, with an upfront payment of $20 million. A milestone payment of $15 million was made in February 2025 upon entry into the Phase 2 trial; however, the remaining $506 million in potential payments is now uncertain. Furthermore, Neuphoria is already in a precarious situation, having experienced a Phase 3 failure for its social anxiety disorder drug 'BNC210 (soclenicant)' in October of last year, and is now exploring options such as restructuring and mergers & acquisitions (M&A) to ensure its survival.
Competitive Landscape in the Alzheimer's Treatment Market
Currently, the global Alzheimer's treatment market is experiencing high growth, with an estimated value of $5.38 billion in 2025 and $7.79 billion in 2026. However, the barriers to entry are also high. The market is currently dominated by amyloid-beta targeting monoclonal antibodies, such as Eisai's 'Leqembi' and Eli Lilly's 'Kisunla'. While MK-1167 was intended to be a convenient oral small molecule, it ultimately failed to effectively cross the blood-brain barrier (BBB) and modulate its target receptor, which proved to be a critical limitation.
Merck's Future Development Roadmap
This discontinuation creates a significant gap in Merck's Alzheimer's pipeline. The only remaining Alzheimer's candidate in Merck's portfolio is 'MK-2214', a tau-targeting antibody acquired from Teijin Pharma, which is expected to complete clinical trials in 2029. Neuphoria's partner, Scancell Holdings (LSE: SCLP), has proposed a reverse merger in the form of a stock swap aimed at a Nasdaq listing, and the two companies are currently discussing survival strategies. Merck should also actively consider introducing new drugs to diversify its pipeline.
Merck's decision to halt the Phase 2 trial of MK-1167 underscores the challenges in developing oral small molecule drugs for the global Alzheimer's treatment market, which is projected to reach $7.79 billion by 2026. In the short term, Neuphoria (NEUP) will be unable to receive the remaining $506 million in milestone payments, which will exacerbate the company's financial uncertainties, including the success of its proposed reverse merger with Scancell (SCLP). In the medium to long term, the gap between Merck and market leaders such as Eisai's Leqembi and Eli Lilly's Kisunla, which are amyloid-beta targeting antibody therapies, is likely to widen. Furthermore, Merck will now have to rely solely on its single tau-targeting pipeline, MK-2214 (Phase 2), which will increase the pressure to introduce new drugs through licensing agreements to diversify its portfolio.