Headquarters: Rahway, New Jersey, USA
Ticker: MRK (NYSE)
Website: [merck.com](https://www.merck.com)
Overview
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Merck & Co., Inc. (known as Merck KGaA outside the United States and Canada) is a global pharmaceutical company headquartered in Rahway, New Jersey. With a history spanning over 130 years, Merck is one of the world's largest pharmaceutical companies by revenue and market capitalization. The company has a significant presence in neuroscience research, including Alzheimer's disease and Parkinson's disease programs["@miller2017"].
History
Merck was founded in 1891 as a subsidiary of Merck KGaA in Germany. The company has grown to become a major force in pharmaceutical research, with numerous breakthrough treatments across oncology, immunology, infectious diseases, and neuroscience[@kesselheim2013].
Neuroscience Pipeline
Funding
IPO: 1940s (NYSE: MRK)
Market Cap: ~$110B (2026)
2025 Revenue: $42B
2024 Revenue: $40B
R&D Investment: ~$10B annually
Alzheimer's Disease
Merck has historically been involved in Alzheimer's disease research, primarily through its BACE inhibitor program[@kennedy2016].
2017: Verubecestat failed in Phase 2/3 EPOCH trial for prodromal AD[@egan2019]
Company shifted focus from BACE inhibition due to safety concerns[@hawkes2017]
Current research focuses on novel approaches including neuroinflammation[@crews2019]
2025-2026 Developments
2025: New neuroinflammation program entered Phase 1 for AD
2025: Strategic partnership announced with small biotech for novel tau targeting
2026: Early-stage Parkinson's program advances to IND-enabling studies
Parkinson's Disease
Merck maintains interest in Parkinson's disease through academic partnerships and early-stage research programs[@kalia2015].
| Program | Mechanism | Stage | Status | |---------|-----------|-------|--------| | Preladenant (SCH-420814) | Adenosine A2A receptor antagonist | Phase 3 | Discontinued | | Undisclosed programs | Various | Discovery/Preclinical | Active |
Preladenant (SCH-420814): Merck developed preladenant, a selective adenosine A2A receptor antagonist for Parkinson's disease. The drug advanced to Phase 3 clinical trials but was discontinued due to insufficient efficacy compared to placebo. The preladenant program represents Merck's historical interest in non-dopaminergic Parkinson's therapeutics targeting the purinergic system. The A2A antagonist approach aimed to improve motor function through antagonism of adenosine A2A receptors in the striatum, offering a non-dopaminergic mechanism that could potentially avoid dyskinesias associated with levodopa therapy.
Research Focus Areas
Merck's current neuroscience research emphasizes:
Neuroinflammation - Targeting microglial activation and neuroinflammation pathways in neurodegenerative diseases[@heneka2015]
Synaptic plasticity - Developing approaches to preserve and restore synaptic function[@selkoe2019]
Protein homeostasis - Modulating protein clearance mechanisms[@soto2010]
Novel targets - Identifying new therapeutic targets through genomics and systems biology
Strategic Partnerships
Merck collaborates with academic institutions and biotech companies on neuroscience research:
Academic partnerships with leading research universities
Biotech collaborations for novel drug delivery technologies
Consortium involvement in Alzheimer's Disease Neuroimaging Initiative (ADNI)[@weiner2016]
[Unknown, Miller, G. The changing landscape of pharmaceutical neuroscience R&D (2017)](https://doi.org/10.1038/nrd.2017.25)
[Unknown, Kesselheim AS, Avorn J. The most transformative drugs of the past 25 years: a survey of physicians (2013)](https://doi.org/10.1001/jamainternmed.2013.7099)
[Kennedy ME, et al., The BACE inhibitor verubecestat (MK-8931) reduces β-amyloid in a Phase 1 study (2016)](https://pubmed.ncbi.nlm.nih.gov/27031957/)
[Egan MF, et al., Randomized Trial of Verubecestat for Prodromal Alzheimer's Disease (2019)](https://doi.org/10.1056/NEJMoa1706441)
[Unknown, Hawkes N. Merck discontinues BACE inhibitor trials for Alzheimer's disease (2017)](https://pubmed.ncbi.nlm.nih.gov/28334851/)
[Unknown, Crews L, Masliah E. Molecular mechanisms of neurodegeneration: targets for novel therapeutics (2019)](https://doi.org/10.1016/j.expneurol.2019.01.010)
[Unknown, Kalia LV, Lang AE. Parkinson's disease (2015)](https://doi.org/10.1016/S0140-6736(15)
[Heneka MT, et al., Neuroinflammation in Alzheimer's disease (2015)](https://doi.org/10.1016/S1474-4422(15)
[Unknown, Soto C, Satani N. The intricate mechanisms of neurodegeneration in Alzheimer disease (2010)](https://doi.org/10.1016/j.drudis.2010.11.003)
[Weiner MW, et al., The Alzheimer's Disease Neuroimaging Initiative: progress report and future directions (2016)](https://pubmed.ncbi.nlm.nih.gov/27570567/)