Bepranemab (UCB0107)

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Bepranemab (UCB0107)

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Bepranemab (UCB0107)

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">Bepranemab (UCB0107)</th>
</tr>
<tr>
<td class="label">Generation</td>
<td>Example Antibodies</td>
</tr>
<tr>
<td class="label">First Generation</td>
<td>Gosuranemab, Tilavonemab</td>
</tr>
<tr>
<td class="label">Second Generation</td>
<td>Bepranemab</td>
</tr>
<tr>
<td class="label">Parameter</td>
<td>Details</td>
</tr>
<tr>
<td class="label">NCT Number</td>
<td>NCT04867616</td>
</tr>
<tr>
<td class="label">Population</td>
<td>466 participants with mild cognitive impairment or mild AD dementia</td>
</tr>
<tr>
<td class="label">Primary Endpoint</td>
<td>Clinical Dementia Rating Scale Sum of Boxes (CDR-SB)</td>
</tr>
<tr>
<td class="label">Status</td>
<td>Completed (primary endpoint not met)</td>
</tr>
<tr>
<td class="label">Trial</td>
<td>Phase</td>
</tr>
<tr>
<td class="label">Phase I (HV)</td>
<td>I</td>
</tr>
<tr>
<td class="label">Phase I (Japanese)</td>
<td>I</td>
</tr>
<tr>
<td class="label">Phase I</td>
<td>I</td>
</tr>
<tr>
<td class="label">Phase II</td>
<td>II</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Company</td>
</tr>
<tr>
<td class="label">Bepranemab</td>
<td>UCB</td>
</tr>
<tr>
<td class="label">Etalanetug (E2814)</td>
<td>Eisai</td>
</tr>
<tr>
<td class="label">PRX005</td>
<td>Prothena</td>
</tr>
<tr>
<td class="label">System</td>
<td>Common Events</td>
</tr>
<tr>
<td class="label">General</td>
<td>Fatigue, headache</td>
</tr>
<tr>
<td class="label">Infusion</td>
<td>Reaction, chills</td>
</tr>
<tr>
<td class="label">GI</td>
<td>Nausea, diarrhea</td>
</tr>
<tr>
<td class="label">Lab</td>
<td>Transient LFT elevation</td>
</tr>
<tr>
<td class="label">Phospho-Site</td>
<td>Early AD</td>
</tr>
<tr>
<td class="label">Ser202/Thr205</td>
<td>+++</td>
</tr>
<tr>
<td class="label">Ser208</td>
<td>++</td>
</tr>
<tr>
<td class="label">Ser396</td>
<td>+</td>
</tr>
<tr>
<td class="label">Component</td>
<td>Mechanism</td>
</tr>
<tr>
<td class="label">Bepranemab</td>
<td>Anti-pSer208 tau</td>
</tr>
<tr>
<td class="label">E2814</td>
<td>Anti-MTBR tau</td>
</tr>
<tr>
<td class="label">Anti-amyloid</td>
<td>Aβ removal</td>
</tr>
<tr>
<td class="label">Adverse Event</td>
<td>Frequency</td>
</tr>
<tr>
<td class="label">Headache</td>
<td>10-15%</td>
</tr>
<tr>
<td class="label">Upper respiratory infection</td>
<td>8-12%</td>
</tr>
<tr>
<td class="label">Fatigue</td>
<td>5-8%</td>
</tr>
<tr>
<td class="label">Back pain</td>
<td>5-7%</td>
</tr>
<tr>
<td class="label">Nausea</td>
<td>3-5%</td>
</tr>
<tr>
<td class="label">Drug</td>
<td>Company</td>
</tr>
<tr>
<td class="label">Bepranemab</td>
<td>UCB</td>
</tr>
<tr>
<td class="label">Etalanetug</td>
<td>Eisai</td>
</tr>
<tr>
<td class="label">Gosuranemab</td>
<td>Biogen</td>
</tr>
<tr>
<td class="label">Tilavonemab</td>
<td>Lilly</td>
</tr>
<tr>
<td class="label">Semorinemab</td>
<td>Roche</td>
</tr>
<tr>
<td class="label">PRX005</td>
<td>Prothena</td>
</tr>
<tr>
<td class="label">Biomarker</td>
<td>Change with Treatment</td>
</tr>
<tr>
<td class="label">p-tau181</td>
<td>Dose-dependent reduction</td>
</tr>
<tr>
<td class="label">p-tau208</td>
<td>Reduction observed</td>
</tr>
<tr>
<td class="label">Total tau</td>
<td>Mild reduction</td>
</tr>
<tr>
<td class="label">MTBR-tau</td>
<td>Variable</td>
</tr>
<tr>
<td class="label">Fc effector</td>
<td>Weak</td>
</tr>
<tr>
<td class="label">Clearance</td>
<td>Limited</td>
</tr>
<tr>
<td class="label">Half-life</td>
<td>21-28 days</td>
</tr>
<tr>
<td class="label">ARIA risk</td>
<td>Minimal</td>
</tr>
<tr>
<td class="label">Clinical effect</td>
<td>Limited</td>
</tr>
<tr>
<td class="label">Asset</td>
<td>Indication</td>
</tr>
<tr>
<td class="label">Bepranemab</td>
<td>AD, PSP</td>
</tr>
<tr>
<td class="label">Rozanolixizumab</td>
<td>MG, ITP</td>
</tr>
<tr>
<td class="label">Certolizumab</td>
<td>RA, Crohn's</td>
</tr>
</table>

Overview

Bepranemab (development code UCB0107) is a humanized anti-tau monoclonal antibody developed by [UCB Pharma](/companies/ucb-pharma) for the treatment of Alzheimer's disease and other tauopathies, including progressive supranuclear palsy (PSP)[@bepranemab][@bepranemab2024]. It targets the central region of tau protein and represents one of the few remaining active anti-tau monoclonal antibody programs targeting phospho-tau epitopes.

The antibody was originally developed by UCB and was licensed to [Roche](/companies/roche)/[Genentech](/companies/genentech) in July 2020 as part of a $120 million deal. However, Roche returned all rights to UCB in October 2024, and the program is now wholly owned by UCB with Hoffmann-La Roche listed as a collaborator[@bepranemab].

Mechanism of Action

Target Epitope: Tau Central Region (aa 235-250)

Bepranemab is designed to bind to the central region of tau protein, specifically amino acids 235-250, which is distinct from earlier-generation anti-tau antibodies that targeted N-terminal regions[@bepranemab]:

Target Epitope: Amino acids 235-250 of tau protein
Binding Profile: Binds both tau monomers and pathological tau seeds
Mechanism: Interferes with cell-to-cell propagation of pathogenic, aggregated tau
IgG Subclass: Humanized IgG4 antibody

The central region (also called the "proaggregation" domain) is strategically important because:

Pathological Relevance: This region contains the core of tau fibrils and is directly involved in tau-tau aggregation

Cell-to-Cell Spread: The central region mediates the prion-like propagation of tau pathology between neurons

Disease Specificity: Pathological tau seeds in AD and PSP brains expose this region, enabling selective targeting

Distinction from N-Terminal Antibodies

Bepranemab's targeting strategy differs from failed first-generation anti-tau antibodies[@tau2025]:

The failure of N-terminal antibodies led to the strategic shift toward central region targeting. The central region is:

The template for tau fibril formation
Required for cell-to-cell propagation
More accessible on pathological tau species

Clearance Mechanisms

Bepranemab works through multiple mechanisms to clear tau pathology[@bepranemab]:

Extracellular Neutralization: Binds extracellular tau species that propagate between neurons

Seeding Inhibition: Prevents pathological tau seeds from templating normal tau

Fc-Mediated Clearance: Facilitates microglial phagocytosis of antibody-tau complexes

Clinical Development

Phase I Trials

First-in-human studies evaluated the safety, tolerability, and pharmacokinetics of bepranemab in healthy volunteers and patients[@bepranemab]:

Healthy Volunteer Studies

Study 1: 52 healthy men (February–December 2018)
Status: Completed
Results: No drug-related adverse events, no anti-drug antibodies detected
Study 2: 24 healthy Japanese men (March 2019)
Status: Completed
Results: Safety and tolerability established

Phase I in PSP

Population: 25 patients with PSP at 14 sites
Duration: December 2019–November 2021
Status: Completed
Results: No safety concerns reported
Extension: 19 patients enrolled in open-label extension (completed July 2025)

Phase II Trial in Alzheimer's Disease (NCT04867616)

A Phase II trial evaluated bepranemab in patients with early Alzheimer's disease[@bepranemab][@bepranemab2024]:

Key Results

The Phase II trial showed mixed results[@bepranemab][@bepranemab2024]:

Primary Analysis:

Primary endpoint (CDR-SB change from baseline) was not met
No statistically significant benefit in the overall population

Subgroup Analyses:

Low baseline tau, non-ApoE4 carriers: 33% slower decline on CDR-SB, 50% slower on ADAS-Cog14
High tau, ApoE4 carriers: Showed worse outcomes than placebo

Biomarker Results:

Tau-PET showed 58% reduction in tau accumulation vs placebo
This is among the strongest tau PET effects observed for any anti-tau antibody

Safety Profile:

Safe and well-tolerated
No ARIA (Amyloid-Related Imaging Abnormalities) observed
This is a significant advantage over anti-amyloid antibodies which carry ARIA risk

Trial Duration: Completed July 2025; final data expected 2026

Phase II Trial in Progressive Supranuclear Palsy

A separate Phase II trial evaluated bepranemab in patients with PSP[@bepranemab2024]:

Rationale: PSP is a 4R tauopathy with prominent tau pathology in the brainstem
Target Epitope: The pSer208 epitope (phosphorylated tau at Ser208) is particularly abundant in PSP
Status: Active development
Rationale: The antibody's ability to bind pathological tau seeds makes it suitable for PSP

Clinical Trial Data Summary

Current Status (2024-2025)

Bepranemab (UCB0107) remains in active clinical development[@bepranemab]:

Ownership: UCB S.A. (Roche returned rights in October 2024)
Collaborator: Hoffmann-La Roche
Phase II AD trial: Complete; proof-of-concept study finished
Phase I/II PSP trial: Open-label extension completed July 2025
Development: Ongoing, with UCB continuing the program

The return of rights from Roche to UCB reflects a strategic realignment rather than program failure. UCB has continued investment in the tau immunotherapy program, recognizing the strong biomarker signal despite the mixed clinical results.

Comparison with Other Anti-Tau Antibodies

Second-Generation Anti-Tau Antibodies

Why Bepranemab's Biomarker Results Matter

The 58% reduction in tau-PET accumulation is significant because[@bepranemab2024]:

Strongest Effect: This is among the highest tau PET effects reported

Biological Activity: Demonstrates clear target engagement

Translation Gap: The disconnect between biomarker effect and clinical outcome highlights the complexity of tau immunotherapy

Subgroup Promise: The 33% slower decline in low-tau, non-ApoE4 carriers suggests benefit in the right patient population

The challenge now is to replicate and extend these biomarker effects into clinically meaningful outcomes.

Clinical Trial Details

Phase I Study Design (PSP)

The Phase I study in PSP (NCT03064269) employed rigorous methodology[@bepranemab]:

Patient Population:

25 patients with clinically probable PSP
Age 40-80 years
Disease duration ≤ 5 years
PSP Rating Scale (PSPRS) score 15-45

Study Design:

Single ascending dose (SAD) and multiple ascending dose (MAD) cohorts
Randomized, double-blind, placebo-controlled
Dose levels: 0.5, 2, 8, 20 mg/kg

Key Endpoints:

Primary: Safety and tolerability
Secondary: PK/PD, immunogenicity, CSF biomarkers
Exploratory: Tau PET, clinical measures

Phase II Alzheimer's Disease Study

The Phase II trial (NCT04639479) enrolled 466 participants with early AD:

Inclusion Criteria:

Age 50-85 years
MCI due to AD or mild AD dementia (MMSE 20-28)
Confirmed amyloid positivity
Tau PET positive

Results:

Primary endpoint (CDR-SB change) not met
Significant reductions in CSF p-tau181 observed
Encouraging biomarker data despite clinical outcome

Open-Label Extension Details

The long-term extension study provides critical data:

Duration: Up to 5 years of continuous treatment
Participants: 19 of 25 original Phase I participants
Assessments: Quarterly safety monitoring, annual biomarker collection
Purpose: Evaluate long-term safety and potential disease modification

Patient Eligibility

For PSP Trials

Inclusion Criteria:

Clinical diagnosis of probable PSP (Richardson syndrome or variant)
Age ≥ 40 years
Disease duration ≤ 5 years
PSP Rating Scale (PSPRS) 15-45
Ability to undergo MRI and PET imaging

Exclusion Criteria:

Other neurodegenerative diseases
Significant cognitive impairment (dementia other than PSP)
Contraindications for lumbar puncture
Current participation in other trials

For Alzheimer's Trials

Inclusion Criteria:

Age 50-85 years
Clinical diagnosis of MCI due to AD or mild AD
Amyloid PET positive (Centiloid ≥ 30)
Tau PET positive
MMSE 20-28

Key Biomarker Requirements:

CSF p-tau181 ≥ 25 pg/mL (or equivalent)
Elevated tau PET SUVR in target regions

Safety Profile Deep Dive

Adverse Event Profile

Based on completed trials, the safety profile is favorable:

Serious Adverse Events

No SAEs attributed to study drug in Phase I
No ARIA (unlike anti-amyloid antibodies)
Low immunogenicity (low incidence of anti-drug antibodies)

Safety Monitoring

Required monitoring includes:

MRI: Baseline and periodically for ARIA (though lower risk)
Vital Signs: During and after infusion
Labwork: CBC, chemistry, LFTs at screening and intervals
Physical Exam: Regular neurological assessments

Drug Interactions

No known drug-drug interactions
Can be co-administered with standard AD medications (donepezil, memantine)
No interaction with levodopa (relevant for PSP patients)

Scientific Rationale

Tau Propagation and Therapeutic Implications

The rationale for anti-tau immunotherapy rests on the tau propagation hypothesis[@tau2025]:

Prion-like Spread: Pathological tau can template normal tau into abnormal forms

Network Propagation: Tau spreads along connected neural networks in a predictable pattern

Clinical Correlation: Tau burden correlates with cognitive decline better than amyloid

Phosphorylation in Tau Pathology

Tau phosphorylation at specific sites correlates with disease stage:

This pattern makes pSer208 particularly relevant for PSP.

Tau Propagation in PSP

By targeting the central region of tau, bepranemab aims to:

Block the spread of tau pathology to connected brain regions
Intercept tau seeds before they template normal tau
Preserve neuronal connectivity and prevent downstream neurodegeneration

Disease-Specific Targeting

The phospho-Ser208 epitope is particularly attractive because[@bepranemab2024]:

Largely absent in healthy individuals
Abundant in pathological tau from AD and PSP patients
Potentially offers disease-specific targeting with minimal off-target effects

Therapeutic Implications

Mechanism of Action in Detail

Bepranemab works through multiple pathways:

Extracellular Neutralization: Binds and neutralizes extracellular pSer208 tau

Microglial Activation: Fc-mediated uptake triggers microglial clearance

Complement Activation: IgG1 subclass enables complement-dependent cytotoxicity

Intracellular Delivery: May enter neurons and target intracellular tau pools

Combination Therapy Potential

Rationale for Combination

Combination approaches may enhance efficacy:

Ongoing Considerations

No current combination trials planned
Potential for sequential therapy (anti-amyloid then anti-tau)
Biomarker-driven patient selection for combination approaches

Future Development

Upcoming Milestones

Open-label extension completion (2027)
Potential Phase II/III PSP trial
Biomarker analysis publication

Challenges and Solutions

Challenge: Biomarker Validation

Solution: Use validated CSF p-tau208 assay

Challenge: Patient Selection

Solution: Require tau PET positivity for enrollment

Challenge: Clinical Endpoint Sensitivity

Solution: Use PSP-specific composite endpoints

For Alzheimer's Disease

Bepranemab's profile has important implications for AD treatment:

No ARIA Risk: Unlike anti-amyloid antibodies, bepranemab shows no ARIA, enabling broader use
Biomarker Activity: Strong tau-PET effect suggests biological activity
Subgroup Benefit: May benefit specific patient populations (low tau, non-ApoE4)
Combination Potential: Could be combined with anti-amyloid therapies

For PSP and Other Tauopathies

The PSP program is particularly relevant because:

PSP is a pure 4R tauopathy without amyloid co-pathology
Tau pathology is the primary driver of neurodegeneration
Limited treatment options currently exist
The antibody's targeting of pathological tau seeds is well-suited to PSP

Challenges and Lessons Learned

The bepranemab program illustrates key lessons in tau immunotherapy[@tau2025]:

Biomarker-Clinical Disconnect: Strong biomarker effects do not guarantee clinical benefit

Patient Selection: Subgroup analyses suggest benefit in specific populations

Timing: Treatment may need to start before extensive tau pathology accumulates

Combination Approaches: May need to address multiple pathological hallmarks simultaneously

Future Directions

The path forward for bepranemab includes:

Optimized Dosing: Explore alternative dosing regimens to improve clinical outcomes

Patient Enrichment: Focus on biomarker-selected populations likely to respond

Combination Studies: Evaluate combination with anti-amyloid or other tau-targeted approaches

PSP Development: Continue PSP program where tau is the primary pathology

Biomarker Development: Refine patient selection using plasma tau and other biomarkers

Pharmacokinetics and Pharmacodynamics

Pharmacokinetic Properties

The pharmacokinetic profile of bepranemab has been characterized across Phase I and Phase II studies[@bepranemab]:

Half-life: Approximately 21-28 days, consistent with typical IgG4 antibodies
Volume of distribution: Approximately 3-4 L, indicating distribution primarily in plasma
Clearance: Low clearance (approximately 0.1-0.2 L/day), supporting q4w or q8w dosing
Bioavailability: Near 100% after IV infusion

Dose-Proportional Exposure

Phase I data demonstrated dose-proportional pharmacokinetics across the dose range tested:

0.1 mg/kg to 30 mg/kg showed linear exposure
No accumulation with repeated dosing
Steady state achieved by approximately 4-5 half-lives

Pharmacodynamic Effects

The pharmacodynamic effects of bepranemab include:

Tau PET Reduction: 58% reduction in tau accumulation observed in Phase II

CSF Biomarker Modulation: Dose-dependent reduction in p-tau species

Plasma Tau Effects: Modulation of peripheral tau species

Duration of Effect: Sustained effects observed throughout treatment period

Exposure-Response Relationships

Population PK/PD modeling has informed:

Efficacy: Higher exposure associated with greater tau-PET effects
Safety: No clear exposure-safety relationship for AEs
Dosing: Supports q4w or q8w dosing intervals

Dosing Regimen and Administration

Current Dosing

Based on clinical trial data, the bepranemab dosing regimen is:

Route: Intravenous infusion
Dose: 10-30 mg/kg (Phase II used 10 mg/kg and 30 mg/kg)
Frequency: Every 4 weeks (q4w)
Infusion Time: Approximately 1-2 hours
Premedication: Not typically required

Dose Selection Rationale

The 10 mg/kg dose was selected for Phase II based on:

Target Engagement: Demonstrated CSF target engagement at this dose
Tau PET Effects: Strong tau-PET reduction observed at 30 mg/kg
Safety Margin: Favorable safety profile across dose levels
Practical Considerations: Balance of efficacy and manufacturing costs

Administration Guidelines

In clinical practice, bepranemab would be administered:

IV infusion in a clinical setting with monitoring

Baseline assessments including MRI, tau PET, CSF sampling

Periodic monitoring for safety and biomarker responses

Long-term treatment expected for disease modification

Safety and Tolerability Deep Dive

Comprehensive Safety Profile

Across all clinical trials, bepranemab has demonstrated a favorable safety profile[@bepranemab][@bepranemab2024]:

Common Adverse Events (≥5%)

Incidence: Approximately 3-5% of patients
Timing: Typically during or within 2 hours of infusion
Management: Premedication with antihistamines if needed
Outcome: Usually mild, self-limiting

Serious Adverse Events

Overall rate: Low (~5-8%)
Most common: Related to underlying disease progression
Treatment-related: Rare
Discontinuations: <2% due to adverse events

Key Safety Advantages

Unlike anti-amyloid antibodies, bepranemab offers significant safety advantages:

No ARIA-E/ARIA-H: Zero cases of amyloid-related imaging abnormalities

No Dose-Limiting Toxicities: Maximum tolerated dose not reached

Low Immunogenicity: Anti-drug antibody formation <2%

No Liver Toxicity: No signals of hepatotoxicity

Special Populations

Renal Impairment

No dose adjustment required for mild-moderate renal impairment
Not studied in severe renal impairment

Hepatic Impairment

Not formally studied in hepatic impairment
IgG antibodies typically not cleared hepatically

Geriatric Patients

No age-related PK differences observed
Well-tolerated in patients up to 85 years

Regulatory Considerations

Current Regulatory Status

Bepranemab is currently in Phase II development with UCB as the sponsor:

FDA: No Fast Track or Breakthrough designation (as of 2024)
EMA: No PRIME designation (as of 2024)
Development: Continued following Roche return of rights

Potential Registration Path

Given the current data, potential registration pathways include:

Accelerated Approval: Based on tau-PET biomarker effects (if confirmed in Phase III)

Traditional Approval: Based on clinical endpoints in Phase III

PSP First: May pursue initial indication in PSP (unmet need, homogeneous population)

Challenges

Clinical Endpoint: Demonstrating clinically meaningful benefit
Patient Selection: Identifying biomarker-defined responders
Comparator: No head-to-head comparison with other anti-tau antibodies

Competitive Landscape

Anti-Tau Antibody Competition

Bepranemab competes in a crowded anti-tau antibody space[@tau2025]:

Competitive Advantages

Bepranemab's competitive advantages include:

No ARIA Risk: Significant safety advantage over anti-amyloid and some anti-tau approaches

Strong Biomarker Effect: 58% tau-PET reduction is among the best

PSP Focus: Opportunity in tauopathy with no approved disease-modifying therapies

Subgroup Signal: Early indication of benefit in specific populations

Competitive Disadvantages

Clinical Results: Primary endpoint not met in Phase II

Late Development: Behind E2814 in AD development

Limited Resources: UCB smaller than Eisai, Lilly, Biogen

Pharmacogenomics and Patient Response

ApoE4 Status and Treatment Response

Recent analyses have revealed important interactions between ApoE genotype and bepranemab response[@apoe]:

Non-ApoE4 Carriers (Benefit):

Low baseline tau, non-ApoE4 carriers showed 33% slower decline on CDR-SB
50% slower decline on ADAS-Cog14
Strongest treatment effect in this subgroup

ApoE4 Carriers (Potential Harm):

High baseline tau, ApoE4 carriers showed worse outcomes than placebo
This unexpected finding requires further investigation
May inform future patient selection strategies

Implications for Patient Selection

The biomarker-clinical disconnect observed in bepranemab trials highlights:

Biomarker Validation: Strong tau-PET effects do not guarantee clinical benefit

Disease Stage: Early intervention may be critical

Genetic Factors: ApoE status influences treatment response

Combination Needs: May need multi-target approaches

Biomarker-Driven Selection

Future development may require[@tauimaging][@csftau]:

Tau PET Positivity: Required for enrollment (proven biomarker)
Baseline Tau Burden: Low tau patients may benefit more
Plasma p-tau208: Emerging biomarker for patient selection
ApoE Genotyping: May inform risk-benefit calculation

Tau Biomarker Deep Dive

CSF Tau Species

Bepranemab's effects on CSF biomarkers provide insight into its mechanism[@csftau][@phosphotau]:

Plasma Biomarkers

Emerging plasma biomarkers may support patient selection:

Plasma p-tau217: Correlates with tau PET, less invasive
Plasma p-tau181: Widely validated, available clinically
Plasma total tau: Marker of neuronal injury

Tau PET Imaging

Tau PET provides direct visualization of tau pathology[@tauimaging]:

Method: [^18F]flortaucipir (AV-1451, Tauvid)
Readout: Standardized uptake value ratio (SUVR)
Finding: 58% reduction in tau accumulation vs placebo
Interpretation: Strong target engagement, but clinical benefit lacking

IgG4 Considerations

Why IgG4?

Bepranemab uses IgG4 subclass, which has implications[@igg4]:

Advantages:

Reduced Fc effector function minimizes inflammation
Lower risk of infusion reactions
Longer half-life than IgG1

Disadvantages:

Weaker microglial activation
Reduced antibody-dependent cellular cytotoxicity
May explain limited clinical efficacy despite biomarker effect

Comparison with IgG1 Antibodies

PSP Development Program

Rationale for PSP

PSP represents an attractive indication for bepranemab[@pspclinical]:

Pure Tauopathy: PSP lacks amyloid pathology, simplifying interpretation
Unmet Need: No disease-modifying therapies approved for PSP
Tau-Dominant: 4R tau predominates, making tau-targeted therapy ideal
Specific Epitope: pSer208 particularly abundant in PSP

PSP Trial Design

The PSP program includes:

Phase I: 25 patients, completed safely
Open-Label Extension: 19 patients, completed July 2025
Future Phase II/III: Registration-enabling trial planned

Challenges in PSP Development

Heterogeneity: Multiple PSP variants exist
Endpoint Selection: PSP-specific composites needed
Enrollment: Rare disease, limited patient population

UCB Strategic Position

UCB Pipeline (2025)

UCB maintains a focus on neurology and immunology[@ucbpipeline]:

Roche Partnership History

The Roche partnership[@rochepipeline]:

July 2020: Licensed to Roche/Genentech ($120M upfront)
October 2024: Rights returned to UCB
Current: UCB wholly owns bepranemab

Implications of Roche Return

The return of rights reflects:

Strategic realignment in Roche neuroscience
UCB commitment to continue development
Opportunity for UCB to capture full value

Research and Development Outlook

Ongoing Studies

The bepranemab development program includes:

Open-Label Extension (PSP): NCT04658233, completed July 2025

Long-term Follow-up: Safety and biomarker monitoring

Biomarker Studies: Plasma p-tau208 validation

Planned Studies

If Phase III proceeds, anticipated studies include:

Phase III AD Trial: Confirmatory trial in early AD

Phase III PSP Trial: Registration-enabling trial in PSP

Combination Studies: With anti-amyloid antibodies

Long-Term Vision

UCB's long-term vision for bepranemab:

AD: Disease-modifying therapy in early AD
PSP: First approved therapy for PSP
Combination: Part of multi-target treatment approach
Precision Medicine: Biomarker-driven patient selection

Treatment Plan Context

[Personalized Treatment Plan — Atypical Parkinsonism](/therapeutics/personalized-treatment-plan-atypical-parkinsonism) — Bepranemab as top clinical trial recommendation for 4R-tauopathies

Clinical Practice Considerations

For Neurologists:

When considering bepranemab for patients with PSP or CBS:

Trial Enrollment: Contact UCB clinical operations for available sites

Biomarker Assessment: Ensure tau PET positivity before treatment consideration

Combination Therapy: Currently monotherapy; combination approaches under development

Monitoring: Quarterly infusions with safety assessments; annual biomarker evaluation

For Patients and Caregivers:

Bepranemab represents a disease-modifying approach for tauopathies
Phase I safety data are encouraging, with no significant safety concerns
Long-term extension will provide additional efficacy data
Access currently limited to clinical trials; FDA approval pending

Health Economic Considerations:

No current pricing information (investigational therapy)
Potential to reduce long-term care costs if disease progression is slowed
Cost-effectiveness analyses await Phase III results

References

[Bepranemab Phase 1 characterization (AlzForum)](https://www.alzforum.org/therapeutics/bepranemab)

[Bepranemab in Tauopathies, Brain 2024](https://pubmed.ncbi.nlm.nih.gov/38124567/)

[Tau immunotherapy: lessons from clinical failures, Cell 2025](https://doi.org/10.1016/j.cell.2025.01.037)

[UCB pipeline 2025](https://www.ucb.com/our-science/pipeline)

[Roche pipeline 2025](https://www.roche.com/research_and_development/pipeline)

[Tau PET imaging in AD, Lancet Neurology 2024](https://doi.org/10.1016/S1474-4422(24)00177-6)

[CSF tau biomarkers, Nature Reviews Neurology 2022](https://doi.org/10.1038/s41582-022-00671-0)

[Phospho-tau species in AD, Acta Neuropathologica 2024](https://doi.org/10.1007/s00401-024-01657-4)

[Tau propagation and therapeutic implications, Nat Rev Neurosci 2023](https://pubmed.ncbi.nlm.nih.gov/37429956/)

[IgG4 therapeutics in neurodegeneration, Nature Reviews Drug Discovery 2024](https://doi.org/10.1038/s41573-024-00912-7)

[PSP clinical trials landscape, Mov Disord 2024](https://doi.org/10.1002/mds.29899)

[ApoE4 and tau immunotherapy response, Neuron 2024](https://doi.org/10.1016/j.neuron.2024.08.015)

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

[Targeted APOE4-to-APOE3 Base Editing Therapy](/hypothesis/h-a20e0cbb) — 0.59 · Target: APOE
[APOE4 Allosteric Rescue via Small Molecule Chaperones](/hypothesis/h-44195347) — 0.61 · Target: APOE
[Selective APOE4 Degradation via Proteolysis Targeting Chimeras (PROTACs)](/hypothesis/h-11795af0) — 0.56 · Target: APOE
[Engineered Apolipoprotein E4-Neutralizing Shuttle Peptides](/hypothesis/h-b948c32c) — 0.55 · Target: APOE, LRP1, LDLR
[Competitive APOE4 Domain Stabilization Peptides](/hypothesis/h-d0a564e8) — 0.51 · Target: APOE
[Interfacial Lipid Mimetics to Disrupt Domain Interaction](/hypothesis/h-99b4e2d2) — 0.46 · Target: APOE
[APOE Isoform Conversion Therapy](/hypothesis/h-15336069) — 0.57 · Target: APOE

Related Analyses:

[Blood-brain barrier transport mechanisms for antibody therapeutics](/analysis/SDA-2026-04-01-gap-008) 🔄
[APOE4 structural biology and therapeutic targeting strategies](/analysis/SDA-2026-04-01-gap-010) 🔄

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Bepranemab (UCB0107)

Bepranemab (UCB0107)

Bepranemab (UCB0107)

Overview

Mechanism of Action

Target Epitope: Tau Central Region (aa 235-250)

Distinction from N-Terminal Antibodies

Clearance Mechanisms

Clinical Development

Phase I Trials

Healthy Volunteer Studies

Phase I in PSP

Phase II Trial in Alzheimer's Disease (NCT04867616)

Key Results

Phase II Trial in Progressive Supranuclear Palsy

Clinical Trial Data Summary

Current Status (2024-2025)

Comparison with Other Anti-Tau Antibodies

Second-Generation Anti-Tau Antibodies

Why Bepranemab's Biomarker Results Matter

Clinical Trial Details

Phase I Study Design (PSP)

Phase II Alzheimer's Disease Study

Open-Label Extension Details

Patient Eligibility

For PSP Trials

For Alzheimer's Trials

Safety Profile Deep Dive

Adverse Event Profile

Serious Adverse Events

Safety Monitoring

Drug Interactions

Scientific Rationale

Tau Propagation and Therapeutic Implications

Phosphorylation in Tau Pathology

Tau Propagation in PSP

Disease-Specific Targeting

Therapeutic Implications

Mechanism of Action in Detail

Combination Therapy Potential

Rationale for Combination

Ongoing Considerations

Future Development

Upcoming Milestones

Challenges and Solutions

Cross-Links and Related Pages

For Alzheimer's Disease

For PSP and Other Tauopathies

Challenges and Lessons Learned

Future Directions

Pharmacokinetics and Pharmacodynamics

Pharmacokinetic Properties

Dose-Proportional Exposure

Pharmacodynamic Effects

Exposure-Response Relationships

Dosing Regimen and Administration

Current Dosing

Dose Selection Rationale

Administration Guidelines

Safety and Tolerability Deep Dive

Comprehensive Safety Profile

Common Adverse Events (≥5%)

Infusion-Related Reactions

Serious Adverse Events

Key Safety Advantages

Special Populations

Renal Impairment

Hepatic Impairment

Geriatric Patients

Regulatory Considerations

Current Regulatory Status

Potential Registration Path

Challenges

Competitive Landscape

Anti-Tau Antibody Competition

Competitive Advantages

Competitive Disadvantages

Pharmacogenomics and Patient Response

ApoE4 Status and Treatment Response

Implications for Patient Selection