immunotherapy-update

AAIC 2026: Immunotherapy and Antibody Therapeutics Update

Conference: [AAIC 2026](/events/aaic-2026) | Dates: July 12-15, 2026 | Location: Excel London, UK

Overview

AAIC 2026: Immunotherapy and Antibody Therapeutics Update

Conference: [AAIC 2026](/events/aaic-2026) | Dates: July 12-15, 2026 | Location: Excel London, UK

Overview

The 2026 Alzheimer's Association International Conference (AAIC) features landmark developments in immunotherapy approaches for Alzheimer's disease and related dementias. With three anti-amyloid antibodies now approved and a robust pipeline of anti-tau immunotherapies in development, the field continues to evolve toward more effective disease-modifying treatments.

This summary captures key presentations on amyloid-targeting immunotherapies, including [Lecanemab (Leqembi)](/therapeutics/lecanemab), [Donanemab (Kisunla)](/therapeutics/donanemab), and emerging antibody therapeutics, along with updates on tau immunotherapy clinical trials.

Anti-Amyloid Immunotherapies: Approved Therapies

Lecanemab (Leqembi)

[Lecanemab](/therapeutics/lecanemab) (brand name Leqembi; development code BAN2401) is a humanized IgG1 monoclonal antibody developed by Eisai and Biogen for the treatment of early Alzheimer's disease. It received full FDA approval in January 2023, representing the first amyloid-targeting antibody to achieve traditional approval based on Phase III clinical trial data[@van2023].

Mechanism of Action

Lecanemab selectively targets soluble [amyloid-beta](/proteins/amyloid-beta) (Aβ) protofibrils, which are highly toxic intermediate aggregates in the amyloid cascade. Unlike earlier anti-amyloid antibodies that primarily targeted monomers or mature plaques, lecanemab's specificity for protofibrils allows it to intercept the most toxic form of Aβ before it can cause widespread neuronal damage.

The antibody-Aβ complex is cleared through multiple pathways:

• Microglial-mediated phagocytosis: Fcγ receptor engagement triggers microglia to engulf antibody-Aβ complexes
• Peripheral sink effect: Binding to plasma Aβ creates a gradient drawing brain Aβ into circulation
• Direct plaque disaggregation: May destabilize existing plaque structure

Clinical Efficacy (Clarity-AD)

The Phase III Clarity-AD trial enrolled 1,795 patients with early AD:

• Primary endpoint: Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB) at 18 months
• Result: Met primary and all key secondary endpoints
• Efficacy: 27% slower clinical decline vs. placebo (difference of 0.45 CDR-SB points)
• Amyloid reduction: Centiloid reduction from 53 to approximately 10 (~81% reduction)

AAIC 2026 Updates

Expected presentations at AAIC 2026 include:

• Long-term safety and efficacy data from the Clarity-OLE open-label extension
• Real-world effectiveness data from clinical practice settings
• Subgroup analyses by genetic background and biomarker status
• New analyses on ARIA (Amyloid-Related Imaging Abnormalities) management protocols

Donanemab (Kisunla)

[Donanemab](/therapeutics/donanemab) (brand name Kisunla) is an intravenous monoclonal antibody approved in the United States for treatment of early symptomatic Alzheimer's disease in adults with confirmed amyloid pathology. It received FDA approval in July 2024[@sims2023][@mcdade2024].

Mechanism of Action

Donanemab differs from other anti-amyloid antibodies in its key mechanism:

• Pyroglutamate Aβ targeting: Binds specifically to N3pG-Aβ, a modification found in mature plaques
• Plaque-selective binding: Prefers deposited plaques over soluble monomers
• Fc-mediated clearance: Triggers microglial phagocytosis through Fcγ receptor engagement
• Rapid plaque reduction: Achieves substantial amyloid clearance within months

Clinical Development

TRAILBLAZER-ALZ 2 (Phase 3):

• Enrolled 1,736 patients with early AD
• Primary endpoint: Change in CDR-SB at 18 months
• Results: Statistically significant slowing of clinical progression
• Tau stratification: Participants divided into low/medium and high tau groups
• Greater benefit observed in participants with lower baseline tau burden

This approach may reduce cumulative ARIA risk, lower treatment costs, and improve patient convenience.

AAIC 2026 Updates

Expected presentations at AAIC 2026 include:

• New analyses on amyloid removal rates and time to plaque clearance
• Subpopulation response data across different demographic groups
• TRAILBLAZER-ALZ 3 prevention trial updates
• Long-term outcomes following limited-duration treatment

Next-Generation Anti-Amyloid Antibodies

Remternetug

Remternetug (RN-413) is a next-generation anti-amyloid antibody from Eli Lilly targeting pyroglutamate-modified amyloid-beta (N3pG-Aβ), similar to the target of donanemab but with enhanced brain penetration.

Development Status

Remternetug has progressed through Phase 1/2 clinical trials in early Alzheimer's disease. The compound represents an effort to improve upon the efficacy seen with donanemab through:

• Enhanced blood-brain barrier penetration
• Optimized Fc region for improved microglial activation
• Higher affinity for pathological Aβ species

AAIC 2026 Expectations

Anticipated data presentations include:

• Phase 1/2 efficacy and safety results
• Biomarker analyses (amyloid PET, CSF biomarkers)
• Dose-response relationships

Emerging Bispecific Antibodies

AAIC 2026 features presentations on novel bispecific antibody approaches that target multiple pathological species simultaneously:

• Dual Aβ/tau targeting: Simultaneous neutralization of amyloid and tau pathology
• Aβ/inflammation targeting: Combined anti-amyloid and microglial modulation
• Trojan horse approaches: Enhanced brain delivery through transporter-mediated uptake

Anti-Tau Immunotherapies

Pipeline Overview

Anti-tau monoclonal antibodies represent the most advanced disease-modifying approach for tauopathies. Unlike kinase inhibitors or aggregation inhibitors, these antibodies directly target pathological tau species and facilitate their clearance through the brain's innate immune system[@danysz2023][@lee2024].

Mechanism of Action

Anti-tau immunotherapies work through multiple mechanisms:

• Antibody binding: Antibodies recognize specific epitopes on tau protein (e.g., p-tau Ser396/404, p-tau Ser202/Thr205, MTBR, total tau)
• Fc receptor-mediated clearance: Antibody-tau complexes are cleared via microglia through Fcγ receptors
• Prevention of spreading: Antibodies neutralize extracellular tau seeds that propagate between neurons
• Reduction of intracellular tau: Some antibodies can enter neurons and clear intracellular aggregates

Clinical Development Pipeline

| Antibody | Company | Target | Phase | Indication |
|----------|---------|--------|-------|-----------|
| Zagotenemab (JNJ-63733657) | Janssen | p-tau | Phase 2 | AD |
| Bepranemab (UCB0107) | UCB | p-tau | Phase 2a | AD |
| Semorinemab (RO7105705) | Roche | Total tau | Phase 2 | AD |
| Tilavonemab (RO69249606) | Roche | p-tau | Phase 2 | PSP |
| Lu AF87908 | Lundbeck | p-tau | Phase 1 | AD |
| E2814 | Eisai | p-tau | Phase 1/2 | AD/DIAN |

AAIC 2026 Updates

Key anti-tau presentations expected at AAIC 2026 include:

• Phase 2 study results for leading anti-tau antibodies
• Biomarker correlations between tau PET changes and clinical outcomes
• Combination approaches with anti-amyloid therapies
• New epitope targeting strategies including MTBR-specific antibodies

Combination Therapy Approaches

Rationale

Multiple pathological pathways require simultaneous targeting in Alzheimer's disease:

• Synergistic effects between different mechanisms
• Lower doses may reduce side effects
• Addressing multiple disease drivers simultaneously

Emerging Combinations

Anti-Amyloid + Anti-Tau:

• Simultaneous pathology reduction
• Clinical trials combining lecanemab/donanemab with anti-tau antibodies
• Rationale: amyloid drives tau spread, blocking both may provide additive benefits

• Addressing microglial activation alongside amyloid clearance
• TREM2-targeting approaches in combination with anti-amyloid
• GLP-1 receptor agonists as adjunct therapy

• Anti-amyloid antibodies combined with cholinesterase inhibitors
• Adjunctive use of existing symptomatic treatments

Safety Considerations

Amyloid-Related Imaging Abnormalities (ARIA)

ARIA remains the primary safety concern for anti-amyloid immunotherapies:

| ARIA Type | Lecanemab | Donanemab |
|-----------|-----------|-----------|
| ARIA-E (edema) | 12.6% | ~24% |
| ARIA-H (hemorrhage) | 17.3% | ~7% |

Monitoring Protocols (updated for AAIC 2026):

• Baseline MRI before first infusion
• MRI at Week 12, Week 24, then as clinically indicated
• APOE ε4 carriers require closer monitoring
• Hold treatment for moderate-severe ARIA

Management Guidelines

Best Practice Updates:

• Early detection of ARIA through symptom monitoring
• Standardized MRI protocols across clinical sites
• Risk stratification based on APOE genotype and baseline imaging
• Guidance on steroid use for moderate-severe ARIA

Clinical Trial Design Innovations

Biomarker-Guided Approaches

AAIC 2026 features advances in clinical trial design:

• Adaptive treatment discontinuation: Stopping therapy based on amyloid clearance
• Personalized patient selection: Using genetic and biomarker profiles for enrollment
• Prevention trial designs: Targeting preclinical AD populations

Outcome Measure Advances

• Primary endpoints: CDR-SB, iADRS, ADAS-Cog13
• Secondary biomarkers: Amyloid PET, tau PET, CSF p-tau181/217/231
• Digital endpoints: Remote monitoring and cognitive assessments

Future Directions

Near-Term Milestones (2026-2027)

• Results from ongoing Phase 3 anti-tau trials
• FDA decisions on additional anti-amyloid antibodies
• Prevention trial results (AHEAD 3-45, DIAN)
• Combination therapy trial initiations

Long-Term Vision

• Earlier intervention in preclinical AD
• Personalized treatment based on biomarker profiles
• Disease modification through multi-target approaches
• Preventative therapies for at-risk individuals

Cross-References

Related NeuroWiki Pages

• [Lecanemab (Leqembi)](/therapeutics/lecanemab)
• [Donanemab (Kisunla)](-/therapeutics/donanemab)
• [Anti-Amyloid Immunotherapy Comparison Matrix](/therapeutics/immunotherapy-comparison)
• [Anti-Tau Immunotherapies](/therapeutics/anti-tau-immunotherapies)
• [Anti-Amyloid Therapies](/therapeutics/anti-amyloid-therapies)
• [AAIC 2026 Conference](/events/aaic-2026)
• [AAIC 2026: Therapeutic Approaches](/events/aaic-2026/therapeutic-approaches)
• [Clinical Trials in Alzheimer's Disease](/clinical-trials/alzheimers-trials)

Mechanism Pathways

• [Amyloid Cascade Hypothesis](/mechanisms/amyloid-cascade-hypothesis)
• [Tau Pathology Pathway](/mechanisms/tau-pathology-pathway)
• [Microglia in Alzheimer's Disease](/mechanisms/trem2-microglia-pathway-alzheimers)

References

External Links

• [AAIC 2026 Official Website](https://aaic.alz.org)
• [ClinicalTrials.gov: Anti-Amyloid Therapies](https://clinicaltrials.gov/search?term=amyloid+antibody+Alzheimer)
• [ClinicalTrials.gov: Anti-Tau Therapies](https://clinicaltrials.gov/search?term=tau+antibody+Alzheimer)
• [Alzforum Therapeutics Database](https://www.alzforum.org/therapeutics)