biib122-luma-lrrk2-inhibitor-pd

BIIB122 (LUMA) LRRK2 Inhibitor Parkinson's Disease Trial

Overview

BIIB122 (also known as DNL151) is a potent, selective, oral small molecule inhibitor of leucine-rich repeat kinase 2 (LRRK2) developed by Biogen in collaboration with Denali Therapeutics. The compound is designed to inhibit the kinase activity of LRRK2, which has been genetically linked to both familial and sporadic Parkinson's disease["@biogen2022"].

The LUMA trial (NCT05348785) is a Phase 2b multicenter study evaluating whether BIIB122 can slow disease progression in early-stage Parkinson's disease patients. This represents one of the most advanced LRRK2 inhibitor programs in clinical development for PD.

Trial Details

BIIB122 (LUMA) LRRK2 Inhibitor Parkinson's Disease Trial

Overview

BIIB122 (also known as DNL151) is a potent, selective, oral small molecule inhibitor of leucine-rich repeat kinase 2 (LRRK2) developed by Biogen in collaboration with Denali Therapeutics. The compound is designed to inhibit the kinase activity of LRRK2, which has been genetically linked to both familial and sporadic Parkinson's disease["@biogen2022"].

The LUMA trial (NCT05348785) is a Phase 2b multicenter study evaluating whether BIIB122 can slow disease progression in early-stage Parkinson's disease patients. This represents one of the most advanced LRRK2 inhibitor programs in clinical development for PD.

Trial Details

| Attribute | Value |
|-----------|-------|
| Trial Name | LUMA |
| NCT Number | NCT05348785 |
| Phase | Phase 2b |
| Status | Active, not recruiting (verified October 2025) |
| Enrollment | 650 participants |
| Start Date | April 19, 2022 |
| Primary Completion | February 25, 2026 |
| Completion Date | March 9, 2026 |

Sponsors and Collaborators

• Lead Sponsor: Biogen
• Collaborator: Denali Therapeutics Inc.

Study Design

• Allocation: Randomized
• Intervention Model: Parallel
• Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
• Primary Purpose: Treatment
• Duration: 48-144 weeks (approximately 1-3 years)

Interventions

| Arm | Intervention | Dose | Route | Frequency |
|-----|--------------|------|-------|------------|
| Experimental | BIIB122 | 225 mg | Oral (tablet) | Once daily |
| Placebo Comparator | BIIB122 Matching Placebo | N/A | Oral (tablet) | Once daily |

Mechanism of Action

LRRK2 Biology in Parkinson's Disease

LRRK2 (Leucine-Rich Repeat Kinase 2) is a large multi-domain protein with intrinsic kinase activity. Pathogenic variants in the LRRK2 gene, particularly the G2019S variant, are among the most common genetic causes of familial PD and also contribute to sporadic disease risk.

LRRK2 hyperactivity leads to:

• Impaired autophagy-lysosomal pathway function
• Mitochondrial dysfunction
• Synaptic alterations
• Increased neuronal vulnerability

BIIB122 Pharmacology

BIIB122 is a highly selective ATP-competitive inhibitor of LRRK2 kinase activity. By inhibiting LRRK2, the drug aims to:

• Restore normal autophagy-lysosomal function
• Improve mitochondrial health
• Reduce alpha-synuclein aggregation susceptibility
• Protect dopaminergic neurons from degeneration

Eligibility Criteria

Key Inclusion Criteria

• Clinical diagnosis of Parkinson's disease within 2 years of screening
• Age 30-80 years at time of PD diagnosis
• Modified Hoehn and Yahr scale stages 1-2 (OFF state)
• MDS-UPDRS Parts II and III combined score ≤50 at screening

Key Exclusion Criteria

• Clinically significant neurological disorder other than PD within 5 years
• Atypical parkinsonism or drug-induced parkinsonism
• Montreal Cognitive Assessment (MoCA) score <24

Primary Outcome

Primary Endpoint: Time to confirmed worsening in MDS-UPDRS Parts II and III combined score, sustained over 2 consecutive assessments, measured up to Week 144.

The MDS-UPDRS (Movement Disorder Society-Unified Parkinson's Disease Rating Scale) is the gold standard for assessing PD severity:

• Part I: Non-motor experiences of daily living (including cognition, psychosis, depression, anxiety)
• Part II: Motor experiences of daily living (activities, tremor, walking, speech)
• Part III: Motor examination (tremor, bradykinesia, rigidity, postural stability)
• Part IV: Motor complications (dyskinesia, motor fluctuations)

Understanding the Endpoint

The choice of "time to confirmed worsening" reflects advances in PD clinical trial design:

Secondary Outcomes

Trial Sites

The trial is conducted at multiple sites across:

• United States
• Austria
• Canada
• China
• France
• Germany
• Israel
• Italy
• Japan
• Netherlands
• Poland
• Spain
• United Kingdom

Data Sharing

Individual participant data will be available through Vivli per Biogen's Clinical Trial Transparency and Data Sharing Policy.

Denali Therapeutics - LRRK2 Program Partnership

Company Background

Denali Therapeutics is a biotechnology company focused on developing therapeutics for neurodegenerative diseases. Founded in 2013, Denali has built a pipeline of programs targeting Alzheimer's disease, Parkinson's disease, and other neurological conditions.

LRRK2 Inhibitor Development History

DNL151 (BIIB122) Development Timeline:

Denali's CNS Delivery Platform

Denali uses proprietary technology to enhance drug delivery to the brain:

Transport Vehicle (TV) Platform:

• Engineered Fc fragments that cross the blood-brain barrier
• Enables delivery of large molecule therapeutics
• Applied to multiple pipeline programs

• Targeting lysosomal dysfunction
• Relevant for LRRK2 biology and autophagy pathways

Scientific Rationale

Genetic Evidence Linking LRRK2 to Parkinson's Disease

The LRRK2 gene encodes Leucine-Rich Repeat Kinase 2, a large (~280 kDa) multi-domain protein with intrinsic kinase activity. Pathogenic variants in LRRK2 represent one of the most common genetic causes of familial Parkinson's disease, accounting for approximately 5-10% of autosomal dominant PD cases.

The G2019S variant, the most prevalent LRRK2 mutation, results in increased kinase activity that has been causally linked to neurodegeneration. Studies have shown that:

• G2019S carriers exhibit earlier onset of PD symptoms
• The variant shows autosomal dominant inheritance with high penetrance
• Both familial and sporadic PD patients carry G2019S variants

Biological Mechanisms

LRRK2 hyperactivity disrupts several critical cellular processes:

• LRRK2 phosphorylates key autophagy regulators
• Impaired clearance of damaged organelles
• Accumulation of protein aggregates
• Reduced mitophagy leading to mitochondrial dysfunction

• Disrupted sorting of membrane proteins
• Altered synaptic vesicle trafficking
• Impaired neuronal signaling

• Increased oxidative stress
• Impaired mitochondrial dynamics
• Reduced neuronal viability

• Changes in neurotransmitter release
• Impaired synaptic plasticity
• Neuronal connectivity deficits

LRRK2 in Sporadic PD

Even in sporadic (non-genetic) Parkinson's disease:

• LRRK2 expression is elevated in PD brains
• LRRK2 kinase activity is increased
• LRRK2 contributes to alpha-synuclein aggregation
• Therapeutic targeting may benefit broader PD population

LRRK2 Inhibitors as Therapeutic Strategy

The rationale for LRRK2 inhibition rests on the genetic evidence that reducing LRRK2 kinase activity can protect neurons:

| Strategy | Mechanism | Evidence Level |
|----------|-----------|---------------|
| Kinase inhibitors | Block ATP binding to LRRK2 | Clinical (BIIB122, DNL151) |
| Antisense oligonucleotides | Reduce LRRK2 mRNA | Preclinical |
| Gene therapy | Modulate LRRK2 expression | Preclinical |

Clinical Development Program

Preclinical Studies

BIIB122 (formerly DNL151) was developed through a rigorous preclinical program:

• In vitro: Potent inhibition of LRRK2 kinase activity (IC₅₀ = 3.1 nM)
• Selectivity: >100-fold selectivity vs. related kinases
• Pharmacokinetics: Favorable oral bioavailability, CNS penetration
• Efficacy: Rescue of LRRK2-mediated phenotypes in cellular models

Phase 1 Results

The Phase 1 program established:

• Safety: Favorable safety and tolerability profile
• PK/PD: Dose-dependent LRRK2 inhibition in peripheral blood
• Target Engagement: Biomarker evidence of pathway modulation
• Maximum Tolerated Dose: Not reached at highest tested dose

Phase 2a (Study 801)

Study Description:

• 24-week treatment in early PD patients
• Multiple dose levels
• Safety and tolerability primary endpoints
• Exploratory efficacy measures

• Well tolerated across dose levels
• No serious adverse events related to study drug
• Target engagement maintained throughout treatment
• Encouraging signal in motor function endpoints

LUMA Phase 2b Design Rationale

Why Phase 2b:

• Large enough to detect clinical efficacy signals
• Long enough duration (up to 144 weeks) to assess disease modification
• Includes patients early in disease course
• Uses validated endpoint (MDS-UPDRS)

• Time to confirmed worsening is disease modification marker
• Requires sustained worsening over 2 visits
• Reduces measurement noise
• Acceptable to regulatory agencies

Competitive Landscape

Other LRRK2 Inhibitors in Development

| Compound | Company | Development Stage | Status |
|----------|---------|-------------------|--------|
| DNL151 (BIIB122) | Biogen/Denali | Phase 2b | Active |
| BAY 239 | Bayer | Phase 1 | Completed |
| ABBV-368 | AbbVie | Phase 1 | Active |
| PR001 | Prevail/Regenxbio | Phase 1/2 | Active (gene therapy) |

Comparison of Approaches

Small Molecule Inhibitors:

• Oral administration
• Can be combined with standard of care
• Potential for long-term use
• Focus on kinase activity inhibition

• AAV-based delivery
• Single administration
• Potential for sustained effect
• Different risk profile

Position in LRRK2 Inhibitor Landscape

| Compound | Company | Status | Mechanism |
|----------|---------|--------|----------|
| BIIB122 (LUMA) | Biogen/Denali | Phase 2b | ATP-competitive |
| MLi-2 | Merck | Preclinical | ATP-competitive |
| DNL151 | Denali | Phase 1 complete | ATP-competitive |

Pharmacokinetics and Pharmacodynamics

PK Properties

Absorption:

• Rapid oral absorption (Tmax 1-2 hours)
• Tablet formulation
• Food effect: minimal

• Moderate protein binding (~70%)
• Volume of distribution: 50-100 L
• Brain penetration demonstrated in preclinical models

• CYP3A4 major pathway
• Metabolites not active
• Low potential for drug-drug interactions

PD Measurements

Target Engagement Biomarkers:

• pS935-LRRK2 in PBMCs (pharmacodynamic marker)
• pT73 NHR2 domain (downstream substrate)
• LRRK2 autophosphorylation

• Target engagement plateau at doses >150 mg
• Steady state reached by day 7
• Reversible upon drug cessation

Biomarker Strategy

The trial employs several biomarkers to assess target engagement:

• Readout of LRRK2 kinase inhibition
• Measured in peripheral blood mononuclear cells
• Validated pharmacodynamic marker

• Alternative phosphorylation site
• Correlates with pathway modulation

Disease Progression Biomarkers

| Biomarker | Tissue | Utility |
|----------|--------|---------|
| Neurofilament light chain (NfL) | CSF/Blood | Neurodegeneration marker |
| Alpha-synuclein | CSF | PD pathology |
| DAT binding | PET | Dopaminergic integrity |

Safety Considerations

Observed Safety Profile

Common Adverse Events:

• Headache (mild, transient)
• Nausea
• Elevated liver enzymes (reversible)
• Diarrhea

• Liver function monitoring required
• Potential for drug interactions
• Long-term safety still being characterized

Preclinical Toxicology

Findings:

• No genotoxicity
• No cardiovascular safety signals
• Reversible changes in kidney at high doses (rodents)
• CNS changes at very high doses (non-relevant exposures)

Monitoring Plan

During Trial:

• Liver function tests every 4 weeks
• Renal function monitoring
• ECG monitoring
• Complete physical examinations

• Long-term follow-up study planned
• Registry participation
• Standard of care monitoring

Statistical Considerations

Sample Size Justification

With 650 participants:

• 80% power to detect 30% risk reduction
• Two-sided alpha = 0.05
• Accounting for dropout (~15%)

Analysis Plan

• Primary: Time-to-event analysis (Cox proportional hazards)
• Secondary: Mixed model for repeated measures
• Sensitivity: Multiple imputation for missing data

Comparison to Standard of Care

| Aspect | LUMA Trial | Standard PD Care |
|--------|------------|-----------------|
| Goal | Disease modification | Symptom control |
| Target | Underlying mechanism | Dopamine replacement |
| Duration | 1-3 years | Chronic |
| Outcome | Slow progression | Improved symptoms |

Regulatory Considerations

Fast Track Designation

BIIB122 received Fast Track designation from FDA in 2021, recognizing:

• Unmet need in Parkinson's disease
• Potential for disease modification
• Good safety profile to date

Registration Pathway

Potential Indications:

• Early Parkinson's disease with LRRK2 mutation (enriched)
• Sporadic Parkinson's disease (broader)
• Possibly G2019S carriers specifically

• Currently targeting early PD regardless of genotype
• May pursue biomarker-selected population in future
• Parallel development in US and EU

Future Directions

Combination Therapy Potential

Rationale:

• LRRK2 inhibition addresses lysosomal dysfunction
• May complement alpha-synuclein targeting approaches
• Could be combined with dopamine replacement

• Combination with standard PD medications
• Adjunct to deep brain stimulation
• Sequential therapy with disease-modifying agents

Biomarker Development

Companion Diagnostics:

• LRRK2 kinase activity assay
• Genetic testing for pathogenic variants
• PET ligands for LRRK2 (research stage)

• G2019S carriers may benefit most
• Sporadic PD patients may also benefit
• Biomarker-driven development possible

If Successful: Phase 3 Development

Positive results from LUMA would support:

Patient Perspective

Potential Benefits

For patients considering participation:

Considerations

• Uncertainty: Unknown efficacy (placebo-controlled)
• Time Commitment: Frequent visits over 1-3 years
• Travel: Site visits may require travel

Related Pages

• [LRRK2 Inhibitors in Parkinson's Disease](/therapeutics/lrrk-inhibitors-parkinsons)
• [LRRK2 Protein](/proteins/lrrk2-protein)
• [LRRK2 Gene](/genes/lrrk2)
• [LRRK2 Pathway in Parkinson's Disease](/mechanisms/lrrk2-pathway-parkinson-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Biogen](/organizations/biogen)
• [Denali Therapeutics](/organizations/denali-therapeutics)
• [Alpha-Synuclein and Parkinson's Disease](/proteins/alpha-synuclein)
• [Autophagy-Lysosome Pathway in Neurodegeneration](/mechanisms/autophagy-lysosome-pathway)
• [Mitochondrial Dysfunction in PD](/mechanisms/mitochondrial-dysfunction-parkinson)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving biib122-luma-lrrk2-inhibitor-pd discovered through SciDEX knowledge graph analysis: