2025 marked a period where neurology gained momentum in its transition from symptom-based classification toward biological confirmation. The promise of "precision medicine" for the brain has begun to take shape, driven by the convergence of fluid biomarkers, digital endpoints, and targeted genetic therapies. The market focus is increasingly prioritizing defining disease biology alongside managing decline; while diagnosis for Alzheimer’s or Parkinson’s remains primarily symptom-based, it is now frequently supported by biological confirmation via blood tests and seeding assays. Investment in 2025 continued to move toward genotype-guided therapies and RNA-based precision tools, establishing a paradigm where a patient’s molecular profile is becoming as integral to their care as their clinical history.

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Breakthroughs & Regulatory Milestones

The year was defined by the transition of experimental technologies into viable clinical tools, from brain-computer interfaces to regulatory-grade surrogate endpoints.

1. uniQure’s Gene Therapy Slows Huntington’s but Faces Regulatory Headwinds
uniQure announced that its gene therapy AMT-130 slowed disease progression by ~75-80% in patients with Huntington’s disease over 36 months, a historic finding for the condition. However, despite the strong biological signal, the FDA signaled concern in late 2025 regarding the reliance on external control data, pushing back on an accelerated approval pathway. This creates a complex landscape where the first potential disease-modifying therapy for Huntington's has proven efficacy but faces significant regulatory friction regarding trial design standards.‍

2. Roche’s Elecsys NfL Cements Role as Regulatory-Grade Surrogate
Roche’s Elecsys Neurofilament Light Chain (NfL) test, previously granted FDA Breakthrough Device Designation, is increasingly utilized as a surrogate endpoint in clinical research. Following the precedent of Tofersen in ALS, NfL reduction is becoming a common "go/no-go" signal in neurodegeneration trials. Roche is positioning the test for monitoring disease activity in MS, seeking to integrate frequent monitoring into broader clinical workflows.

3. Neuralink Demonstrates "Telepathy" Utility Amidst Hardware Challenges
Neuralink reported data from its PRIME trials showing that patients with quadriplegia achieved thousands of hours of system use. While these early-phase studies demonstrate the potential for individuals to control digital devices, the path to routine care remains long. External analyses highlighted ongoing hardware challenges, such as electrode retraction, which complicate long-term durability. While the "Telepathy" milestone represents a leap in restoring digital autonomy, mainstream therapeutic deployment remains years away.‍

4. Precision Psychiatry Advances with Genotype-Guided Prescribing
A study in JAMA Psychiatry demonstrated that patients with treatment-resistant depression carrying specific biomarkers (such as ANK3) showed improved outcomes with targeted therapies like liafensine. This development supports the concept of "Precision Psychiatry," suggesting that some psychiatric disorders can be stratified by biological drivers, potentially enabling more targeted treatment algorithms in the future.

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Strategic M&A

Pharma giants placed massive bets on RNA therapies and oral small molecules, moving beyond monoclonal antibodies to next-generation modalities

1. Novartis Acquires Avidity Biosciences ($12B)
Novartis acquired Avidity Biosciences for approximately $12 billion, an endorsement of Antibody Oligonucleotide Conjugates (AOCs). This deal is primarily driven by Avidity's unique delivery technology, which allows RNA therapies to reach muscle and heart tissue, targets previously difficult to access. This signals a strategic pivot for Novartis toward treating rare neuromuscular diseases at their genetic root.‍

2. Sanofi Expands Neuro Pipeline with Vigil Neuroscience Asset
Sanofi acquired Vigil Neuroscience's small molecule TREM2 agonist program to bolster its neuroinflammation pipeline. This deal highlights the industry's shift toward "Microglial Medicine," targeting the brain's immune system to treat neurodegeneration. Unlike amyloid-clearing antibodies, this approach aims to rejuvenate the brain's natural cleanup crew, representing a diversification of Alzheimer’s strategy toward oral, non-invasive therapies that can be combined with standard anti-amyloid standards of care.

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Alzheimer's & Parkinson's Frontiers

The democratization of diagnosis and the diversification of therapeutic targets redefined the landscape for the world's most prevalent neurodegenerative diseases.

1. Fujirebio Launches First FDA-Cleared Blood Test for Alzheimer’s
Fujirebio received FDA clearance for its Lumipulse G pTau 217/β-Amyloid plasma test, establishing it as the first IVD blood test to aid in Alzheimer’s diagnosis. The clearance frames the test as a tool to support clinical evaluation, potentially removing the bottleneck of PET scans for treatment eligibility.‍

2. C2N Diagnostics Achieves National Coverage with NY Approval
C2N Diagnostics secured a permit from the New York State Department of Health, making its PrecivityAD2 and PrecivityAD tests available in all 50 U.S. states. This expansion reinforces the field's dual-market structure: C2N’s LDTs are utilized for specialized clinical evaluations, while IVD kits target broader screening.

3. Biogen & Eisai File for Subcutaneous Leqembi Approval
Biogen and Eisai completed the rolling submission for a subcutaneous autoinjector version of Leqembi (lecanemab). This development could potentially address a significant adoption barrier for anti-amyloid therapies: the burden of bi-weekly infusion center visits. By shifting administration to a format that can be managed at home or in local clinics, this model may increase access to treatment and reduce the strain on hospital infusion infrastructure.

4. Novo Nordisk Announces Semaglutide Fails to Slow Cognitive Decline in Alzheimer's Trial
In a setback for the "metabolic-neuro" thesis, Novo Nordisk announced that semaglutide failed to slow the progression of Alzheimer's in Phase 3 EVOKE trials. While the drug improved certain biomarkers, it did not lead to statistically significant preservation of cognitive function, suggesting that GLP-1s may not be a standalone neuroprotective solution for established dementia.‍

5. Alpha-Synuclein Seeding Assays Enter Clinical Mainstream
Researchers successfully validated a new fluid protein marker for Parkinson's disease based on misfolded alpha-synuclein. This could enable biological classification for PD for timely identification and intervention, potentially slowing disease progression and improving patient outcomes. In the future, it could be used to monitor disease progression, guide treatment decisions, and accelerate the development of new drugs. Ultimately, very early identification and classification will enable trials to prevent larger PD motor symptoms by very early intervention.

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