Latest Advances in Parkinson's Disease Research

Parkinson's disease research entered one of its most consequential periods between 2024 and early 2026, with three new FDA drug approvals, a landmark Phase 3 failure that reshaped the neuroprotection field, the first large-scale cell therapy trial, and biomarker advances that are redefining how the disease is diagnosed. This article covers the most significant developments, explains what they mean for patients, and clearly distinguishes approved treatments from experimental approaches.

New FDA-Approved Treatments (2024–2025)

Three new treatments received FDA approval in the 18 months between mid-2024 and early 2025, each addressing a different gap in the current treatment landscape. All three are symptomatic treatments — they improve motor symptoms but do not slow the underlying disease.

Crexont (Carbidopa/Levodopa Extended-Release Capsules)

Approved by the FDA in August 2024, Crexont is a novel oral formulation of carbidopa and levodopa that combines both extended-release and immediate-release components within a single capsule. The design aims to provide rapid onset of symptom relief (from the immediate-release component) with prolonged duration (from the extended-release beads), potentially reducing the frequency of dosing and smoothing out motor fluctuations.

For patients who experience wearing-off episodes — periods when the medication stops working before the next dose is due — Crexont offers another formulation option to discuss with their neurologist. It does not replace existing levodopa formulations but adds to the available tools for managing motor fluctuations.

VYALEV (Foscarbidopa/Foslevodopa Subcutaneous Infusion)

Approved in October 2024, VYALEV is the first subcutaneous 24-hour continuous infusion system for Parkinson's disease. It delivers foscarbidopa and foslevodopa (prodrugs that convert to carbidopa and levodopa in the body) through a small pump worn on the body, providing continuous drug delivery that bypasses the gastrointestinal tract.

VYALEV is indicated for the treatment of motor fluctuations in adults with advanced Parkinson's disease. By maintaining steady drug levels around the clock, it can significantly reduce both "off" time and troublesome dyskinesia in patients whose symptoms are no longer adequately controlled with oral medications. The continuous subcutaneous delivery route is less invasive than existing intestinal gel infusion systems (such as Duopa), which require a surgically placed tube.

Onapgo (Apomorphine HCl Subcutaneous Infusion)

Approved on February 4, 2025, Onapgo is the first continuous subcutaneous infusion-based apomorphine therapy available in the United States. Apomorphine is a potent dopamine agonist that has been available for decades as an on-demand subcutaneous injection (Apokyn) and sublingual film (Kynmobi) for rescuing "off" episodes. Onapgo extends this by delivering apomorphine continuously via a wearable pump, providing sustained dopaminergic stimulation.

Onapgo is indicated for "off" episodes and motor fluctuations in people with advancing Parkinson's disease. Continuous apomorphine infusion has been used extensively in Europe and the UK for years and has a well-established safety profile. Its approval in the U.S. fills a long-standing gap in the available treatment options for advanced disease.

Tavapadon (NDA Under FDA Review)

While not yet approved, tavapadon represents a novel mechanism of action for Parkinson's treatment. Developed by AbbVie, tavapadon is a selective partial agonist of D1 and D5 dopamine receptors — a fundamentally different mechanism from existing dopamine agonists (pramipexole, ropinirole, rotigotine), which primarily target D2 and D3 receptors.

AbbVie submitted a New Drug Application (NDA) to the FDA on September 26, 2025, based on the positive Phase 3 TEMPO clinical trial program. In Phase 3 trials, tavapadon showed significant improvements on the MDS-UPDRS (Movement Disorder Society Unified Parkinson's Disease Rating Scale), increased "on" time without troublesome dyskinesia, and a favorable long-term safety profile. An FDA decision is expected in Q3 2026. If approved, tavapadon would be the first D1/D5 partial agonist available for Parkinson's disease.

Adaptive Deep Brain Stimulation

Deep brain stimulation (DBS) has been a standard surgical treatment for Parkinson's since the late 1990s. Conventional DBS delivers continuous electrical stimulation to the subthalamic nucleus (STN) or globus pallidus internus (GPi) at settings programmed during clinic visits. Adaptive DBS (aDBS) represents the next generation: the device continuously reads brain signals and adjusts stimulation in real time based on the patient's current neural activity.

Early randomized feasibility trials have shown that adaptive DBS can provide better control of motor symptoms than conventional constant-stimulation DBS, with a patient's most bothersome symptom and gait among the areas showing the most consistent benefits, though these findings come from small studies that need confirmation in larger trials. The Medtronic BrainSense technology, integrated into the Percept PC neurostimulator, enables clinicians to record and visualize brain signals during programming, a foundational step toward fully closed-loop adaptive stimulation.

Separately, five-year outcome data for conventional DBS published in JAMA Neurology in 2025 confirmed sustained long-term improvements in motor function, dyskinesia suppression, activities of daily living, and medication reduction — reinforcing DBS as an effective option for well-selected candidates with levodopa-responsive motor fluctuations.

MR-Guided Focused Ultrasound Expansion

MR-guided focused ultrasound (MRgFUS), a noninvasive alternative to DBS, received expanded FDA clearance in 2025 for bilateral staged treatment. Previously approved only for unilateral treatment of tremor-dominant Parkinson's (2018) and expanded for rigidity, bradykinesia, and dyskinesia (2021), the bilateral staged approach allows treatment of both sides of the brain in two separate sessions spaced at least six months apart. The procedure requires no incisions, no implanted hardware, and no general anesthesia, and is typically completed within an hour per session.

Alpha-Synuclein: The Central Target for Disease Modification

Alpha-synuclein is a protein that misfolds and clumps together in the brains of people with Parkinson's disease, forming toxic aggregates called Lewy bodies. These aggregates are believed to drive neuronal death through multiple mechanisms including disruption of mitochondria, oxidative stress, and impaired cellular waste disposal. Targeting alpha-synuclein remains the most actively pursued disease-modification strategy.

Prasinezumab Phase 3 (November 2025)

Prasinezumab, an anti-alpha-synuclein monoclonal antibody developed by Roche and Prothena, is the most advanced program in this class. Its journey illustrates both the promise and complexity of disease-modification research:

• Phase II PASADENA trial: Did not meet its primary MDS-UPDRS composite endpoint, but post-hoc analyses showed slower motor progression on Part III (the motor examination component).
• Phase IIb PADOVA trial (586 patients, 18+ months): Narrowly missed its primary endpoint of time to confirmed motor progression (hazard ratio 0.84, p=0.0657). However, a pre-specified subgroup of patients already taking levodopa showed a statistically significant result (HR=0.79, p=0.04), and more than 900 participants across studies have been treated with a favorable safety profile.
• Phase 3 (initiated November 2025): A 900-patient, two-year treatment trial designed to definitively test whether prasinezumab slows motor progression. Completion is expected in June 2029.

It is important to note that prasinezumab has not yet proven disease-modifying efficacy. The Phase 2 results were suggestive but not conclusive, and another alpha-synuclein antibody, cinpanemab (Biogen), showed no difference from placebo in a Phase 2 trial published in the New England Journal of Medicine in 2022 and was discontinued. Whether targeting alpha-synuclein after symptom onset can meaningfully change the disease course remains an open scientific question.

Other Alpha-Synuclein Approaches

• Antisense oligonucleotides (ASOs): Synthetic molecules that reduce alpha-synuclein production by targeting its messenger RNA. This approach is in early human testing, with preclinical evidence showing prevention and reversal of pathology.
• Lu AF82422 (Lundbeck): Another alpha-synuclein antibody with Phase 1 results published in 2024.
• Small-molecule inhibitors: Drugs designed to prevent alpha-synuclein misfolding or aggregation are in early-stage clinical trials.

GLP-1 Receptor Agonists: Mixed Results Require Careful Interpretation

GLP-1 (glucagon-like peptide-1) receptor agonists, originally developed for type 2 diabetes, attracted intense interest as potential neuroprotective agents for Parkinson's disease after promising preclinical results and early clinical signals. However, the clinical trial data to date paint a mixed picture that requires honest assessment.

What the Trials Have Shown

• Lixisenatide (LIXIPARK, NEJM 2024): The most positive result among GLP-1 agonists tested in Parkinson's. This Phase 2 trial showed that lixisenatide modestly reduced motor disability progression over 12 months compared to placebo. However, the effect size was small, and 46% of participants experienced nausea and 13% experienced vomiting.
• Exenatide Phase 3 (Lancet, 2025): This definitive trial failed to meet its primary efficacy endpoint. An earlier Phase 2 trial of exenatide published in The Lancet in 2017 had shown sustained motor improvements after a washout period, generating significant excitement. The Phase 3 result did not confirm this, effectively ending the exenatide-for-Parkinson's hypothesis.
• Liraglutide and NLY01: Trial results have been inconclusive.

Overall assessment: Of six published trials of four GLP-1 family members, only lixisenatide showed superiority to placebo, and even that result was modest. The Parkinson's Foundation explicitly states that GLP-1 drugs like Ozempic are not proven treatments for Parkinson's disease and should not be used outside research settings. The MOST-ABLE trial of semaglutide in Parkinson's disease was completing enrollment as of March 2026, and its results will further clarify the role (if any) of this drug class.

Biomarkers: Transforming Diagnosis and Trial Design

Advances in biomarker science are arguably as important as any drug development, because they change the fundamental ability to detect the disease, select appropriate patients for trials, and measure whether experimental treatments truly slow progression.

Alpha-Synuclein Seed Amplification Assay (SAA)

The alpha-synuclein SAA detects misfolded alpha-synuclein in cerebrospinal fluid with high sensitivity and specificity. Data from the Parkinson's Progression Markers Initiative (PPMI), a landmark longitudinal study funded by the Michael J. Fox Foundation, demonstrated that SAA can identify people with Parkinson's pathology before motor symptoms appear. In February 2026, a review in Nature Reviews Neurology examined the emerging role of biomarker-based diagnosis, moving toward a biological definition of the disease rather than one based purely on clinical symptoms.

The SAA is not yet routine clinical practice, but it is being used in clinical trials to identify participants at the earliest disease stages — the stage when disease-modifying therapies are most likely to be effective. Researchers are also developing blood-based versions of the test, which would be far less invasive.

Blood-Based Biomarkers and Digital Monitoring

Multiple research groups are developing blood tests that detect Parkinson's-related changes, including neurofilament light chain (NfL, indicating neuronal damage), specific phosphorylated forms of alpha-synuclein, and inflammatory markers. Concurrently, wearable sensors and smartphone-based digital biomarkers are providing continuous, objective motor data between clinic visits, improving both clinical care and trial design.

The Gut-Brain Connection

Research into the gut-brain axis continues to yield important findings. Evidence supports the hypothesis that in some cases, alpha-synuclein pathology may begin in the gut's nervous system and spread to the brain via the vagus nerve (the Braak hypothesis). Consistent gut dysbiosis — reduced short-chain fatty acid-producing bacteria and elevated pro-inflammatory species — has been documented in people with Parkinson's, and gastrointestinal symptoms often appear years before motor symptoms.

In LRRK2-mutant mice, oral exposure to Escherichia coli has been shown to trigger alpha-synuclein pathology in the colon that then spreads to the central nervous system via the gut-brain axis. However, therapeutic applications remain early-stage. No standardized microbiome-based treatment is validated for Parkinson's. Probiotics, prebiotics, dietary strategies, and fecal microbiota transplantation show preclinical promise but lack definitive human evidence.

Gene Therapy and Cell Therapy Milestones

Two other areas of research achieved significant milestones during this period:

• AB-1005 GDNF gene therapy received FDA Regenerative Medicine Advanced Therapy (RMAT) designation in February 2025. The Phase 2 REGENERATE-PD trial is still enrolling, with estimated primary completion in 2028. See our gene therapy article for details.
• Bemdaneprocel (BlueRock/Bayer) became the first stem cell-derived dopamine neuron therapy to enter Phase 3 testing, with the first patient treated in the exPDite-2 trial in September 2025. See our stem cell article for details.

LRRK2 and GBA-Targeted Therapies

Precision medicine approaches targeting specific genetic forms of Parkinson's are advancing:

• LRRK2 inhibitors: LRRK2 mutations are the most common genetic cause of familial Parkinson's and are also implicated in immune dysfunction relevant to non-genetic forms. BIIB122 (Biogen/Denali) was the most advanced LRRK2 inhibitor, but its Phase 2b LUMA trial failed to slow progression and was discontinued for idiopathic PD in May 2026; a separate Phase 2a study (BEACON) in LRRK2-variant carriers continues.
• GCase activators/enhancers: GBA mutations are the most common genetic risk factor for Parkinson's, found in 10-15% of sporadic cases. BIA 28-6156 (ACTIVATE trial) targeted glucocerebrosidase activity but failed its Phase 2b endpoints and was discontinued in June 2026; GT-02287 (Gain Therapeutics) remains in Phase 1b, with extension data expected in September 2026.

Upcoming Trials to Watch

• SLEIPNIR platform (Cure Parkinson's): A clinical trial platform designed for rapid assessment of multiple disease-modifying drugs simultaneously, with recruitment beginning in 2026.
• DAPA-PD Phase 2: Testing dapansutrile, an NLRP3 inflammasome inhibitor, for neuroinflammation in Parkinson's. Recruitment began early 2026.
• ARISE trial: Testing solengepras (Cerevance) as an adjunctive therapy for motor fluctuations. Enrollment completed in May 2026, with topline data expected at the end of Q3 2026.

Keeping Perspective

The breadth of current research is genuinely unprecedented, but maintaining realistic expectations is essential. The GLP-1 agonist experience illustrates why: a promising preclinical rationale and an encouraging Phase 2 result led to a Phase 3 trial that did not confirm the benefit. This trajectory — common in neurodegenerative disease research — is not failure in the traditional sense; each trial teaches the field something important about disease biology and trial design.

The best thing a person with Parkinson's can do today is optimize symptom management with currently available treatments, exercise regularly (the most evidence-supported neuroprotective behavior), and consider participating in clinical trials. Discuss any research findings with your movement disorder specialist before making treatment decisions. For research updates and trial matching, the Michael J. Fox Foundation (michaeljfox.org) and the Parkinson's Foundation (parkinson.org) are the most reliable sources.