The late-breaking science sessions at AAN Annual Meeting 2026, Chicago, IL, USA brought together a wide range of pivotal and practice-shaping data spanning rare disease, neuroimmunology, headache, epilepsy, neurodegeneration and neuromuscular medicine.
Several presentations reported positive phase III findings, while others offered important lessons from negative studies, biomarker research and emerging therapeutic platforms.
This article covers presentations highlighted in the LS1: Late-breaking Science 1 and LS2: Late-breaking Science 2 sessions at the AAN Annual Meeting 2026.
Rare disease and neurometabolic disorders
Levacetylleucine meets primary endpoint in ataxia-telangiectasia
One of the headline positive studies from Session 1 was the global phase III IB1001-303 trial of levacetylleucine in children and adults with ataxia-telangiectasia, presented by Dr Marc Patterson. The study met its primary endpoint, demonstrating a statistically significant improvement in Scale for the Assessment and Rating of Ataxia scores versus placebo. Investigators also reported gains in function and quality of life, with a favorable tolerability profile.1
The results position levacetylleucine as a potential targeted treatment option in a rare condition with major unmet need.
Tiomolibdate choline outperforms standard care in Wilson disease
In neurologic Wilson disease, phase III FoCus data suggested tiomolibdate choline may offer superior outcomes versus standard care. The data, presented by Dr Peter Hedera, showed patients receiving therapy showed significant improvements in neurologic rating scales at 48 weeks, with continued benefit through 96 weeks. Fewer patients worsened clinically compared with standard treatment.2
Negative pivotal result for ManNAc in GNE myopathy
The MAGiNE study of N-acetylmannosamine in GNE myopathy did not meet its primary endpoint, with no significant slowing in muscle strength decline versus placebo. The data, presented by Dr Francis Rossignol, while disappointing, provided important insight into disease biology and may guide future combination or next-generation strategies.3
Headache and pain medicine
Three-year atogepant data reinforce durability in migraine prevention
Long-term extension data for atogepant showed sustained reductions in monthly migraine days through 156 weeks, with no new safety signals. The results, presented by Dr Jonathan Smith, strengthen confidence in long-term use of oral calcitonin gene-related peptide receptor antagonists for preventive migraine management.4
Crisugabalin shows phase III efficacy in central neuropathic pain
A separate phase III study, presented by Dr Xiaochong Fan, found crisugabalin significantly reduced pain scores in patients with moderate-to-severe central neuropathic pain, including post-stroke pain and pain following spinal cord injury. Improvements in sleep, mood and quality of life were also reported.5
Epilepsy and seizure disorders
Azetukalner advances in focal onset seizures
The phase III X-TOLE2 study, presented by Prof. Jacqueline French, evaluated azetukalner, a novel KV7 channel opener, in adults with focal onset seizures. While full efficacy results were reserved for presentation, the program is considered pivotal and may support regulatory submission. If positive, azetukalner could represent a mechanistically distinct addition to the antiseizure treatment landscape.6
Reassuring breastfeeding data from the MONEAD trial
The MONEAD study, presented by Prof. Kimford Meador, delivered clinically relevant reassurance for women with epilepsy. Investigators found breastfeeding while taking antiseizure medications was not associated with adverse verbal or behavioral outcomes in children at six years of age.7
Multiple sclerosis and neuroimmunology
Fenebrutinib phase III data highly anticipated in relapsing MS
Among the most closely watched presentations was the FENhance 1 and 2 program evaluating fenebrutinib versus teriflunomide in relapsing multiple sclerosis, presented by Dr Jiwon Oh. Bruton’s tyrosine kinase inhibition remains one of the most competitive areas in multiple sclerosis drug development, and these studies may help determine whether fenebrutinib can succeed where earlier agents have struggled.8
Results showed superiority of investigational fenebrutinib compared to teriflunomide in reducing relapses and brain lesions in relapsing multiple sclerosis (RMS). Both studies showed positive trends in reducing disability progression with fenebrutinib compared to teriflunomide.
Rapid aquaporin-4 antibody testing shows promise in NMOSD
An international evaluation of a rapid immunodot assay (iDOT) for aquaporin-4 antibodies demonstrated strong specificity and encouraging sensitivity for neuromyelitis optica spectrum disorder, presented by Dr Matteo Gastaldi. If validated further, rapid testing could improve diagnostic access and speed in NMOSD care pathways.9
Novel immune reconstitution strategy explored in progressive multifocal leukoencephalopathy (PML)
Pilot data, presented by Dr Yair Mina, on long-acting interleukin-7 (NT-I7) in PML showed meaningful lymphocyte expansion in most treated patients. Although survival benefits were limited, the study provides proof of concept for immune reconstitution approaches in this devastating condition.10
High-throughput antibody profiling may transform encephalitis diagnosis
Researchers also presented a high-throughput reactome platform capable of distinguishing infectious from autoimmune encephalitis with strong accuracy. Such tools may eventually shorten time to diagnosis in complex neuroinflammatory presentations.11
Neurodegeneration and biomarkers
Plasma neurofilament light may predict amyotrophic lateral sclerosis (ALS) years before diagnosis
A notable biomarker study reported elevated plasma neurofilament light levels up to 14 years before diagnosis of amyotrophic lateral sclerosis. The findings suggest a much longer prodromal phase than previously recognized and could have major implications for future prevention trials.12
Donanemab extension data support continued amyloid lowering
Dr Curt Schreiber presented further analysis from TRAILBLAZER-ALZ 2 examined participants who required extended donanemab treatment. Clinical slowing of decline remained consistent, while higher baseline amyloid burden and APOE4 carriership were linked to longer treatment duration.13
Latozinemab raises progranulin but misses clinical endpoints in FTD-GRN
Arthur Mayorga presented results from the INFRONT-3 trial, which showed robust target engagement for latozinemab, with substantial increases in progranulin levels in frontotemporal dementia caused by GRN mutations. However, no slowing of disease progression was observed, highlighting the challenge of translating biomarker success into clinical benefit.14
ATH434 suggests disease-modifying potential in multiple system atrophy
Dr Daniel Claassen presented results on ATH434, an iron chaperone designed to reduce alpha-synuclein aggregation. The study demonstrated signals of slowed functional decline in multiple system atrophy using the MuSyCA composite scale. The findings may help reinvigorate disease-modifying research in MSA.15
Neuromuscular and autoimmune breakthroughs
Deramiocel slows upper limb decline in Duchenne muscular dystrophy
Phase III HOPE-3 results, presented by Dr Aravindhan Veerapandiyan, showed deramiocel significantly slowed upper limb functional decline in Duchenne muscular dystrophy over 12 months, including preservation of feeding-related function. These clinically meaningful outcomes could be particularly relevant for later-stage disease.16
CAR T-cell therapy shows striking activity in stiff person syndrome
One of the most talked-about datasets came from KYSA-8, where CD19 CAR T-cell therapy miv-cel produced rapid and durable improvements in stiff person syndrome. Dr Amanda Piquet presented the results, showing how patients achieved immunotherapy-free remissions with manageable toxicity, raising the prospect that cell therapy may reshape treatment of severe autoimmune neurology disorders.17
Outlook from AAN 2026
Across both late-breaking sessions, the message was clear: neurology innovation is accelerating. From cell therapy in autoimmune disease to biomarker-led prevention strategies and new options in rare genetic disorders, AAN Annual Meeting 2026 showcased a pipeline that is increasingly precise, biologically targeted and clinically ambitious.
References
- Patterson M. Results from the Global Phase 3 Trial (IB1001-303) Evaluating Levacetylleucine in Children and Adults with Ataxia-Telangiectasia. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Hedera P. Greater Clinical Benefit with Tiomolibdate Choline Versus Standard-of-Care in Neurologic Wilson Disease Patients in the Phase 3 FoCus Trial. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Rossignol F. A Pivotal, Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial of N-acetylmannosamine in GNE Myopathy: Results from the NN109 MAGiNE Study. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 21 April 2026.
- Smith J. Long-Term Safety, Tolerability, and Efficacy of Atogepant for the Preventive Treatment of Migraine: Final Results from a Phase 3, Open-Label, 156-Week, Long-Term Safety Extension Study. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Fan X. Efficacy and Safety of Crisugabalin in Patients with Moderate-to-Severe Central Neuropathic Pain: A Phase 3 Randomized Clinical Trial. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
- French J. Results from the Phase 3 X-TOLE2 Study Evaluating Azetukalner, a Novel, Potent KV7 Channel Opener, in Adults with Focal Onset Seizures. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Meador K. Breastfeeding and Subsequent Neuropsychological Outcomes at Age 6 Years in the MONEAD Study. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
- Oh J. Efficacy and Safety of Fenebrutinib versus Teriflunomide in Relapsing Multiple Sclerosis: Results of the FENhance 1 and 2 Studies. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
- Gastaldi M. International Evaluation of the Aquaporin-4 Antibody Rapid iDOT Test. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Mina Y. Long-Acting IL-7 (NT-I7) as an Immune Reconstitution Strategy in PML: Immunological and Clinical Outcomes from a Pilot Study. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Acero-Garces D. High-Throughput Profiling of Anti-Viral and Self-Antigen Antibodies to Identify Etiology in Encephalitis. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Davias A. Association between Pre-Disease Plasma Neurofilament Light Polypeptide Biomarker and Amyotrophic Lateral Sclerosis Risk in the Danish Diet, Cancer and Health Study Cohort. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 19 April 2026.
- Schreiber C. Characterization of “Early-Start” Participants that Continued Receiving Donanemab in the TRAILBLAZER-ALZ 2 Long-Term Extension Period. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
- Mayorga A. Efficacy and Safety Results of INFRONT-3: A Phase 3 Randomized, Double-Blind, Placebo-Controlled Study Evaluating Latozinemab in FTD-GRN. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 21 April 2026.
- Claassen D. ATH434 Demonstrates Disease-Modifying Signal in Multiple System Atrophy Using the MuSyCA Composite Scale. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
- Veerapandiyan A. Deramiocel Significantly Slows Upper Limb Functional Decline in Duchenne Muscular Dystrophy: Skeletal Muscle Outcomes from the Phase 3 HOPE-3 Trial. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 21 April 2026.
- Piquet A. Miv-cel CD19 CAR T-Cell Therapy Shows Efficacy and Safety in Stiff Person Syndrome in a Pivotal, Multicenter, Phase 2 Study. Presented at: AAN Annual Meeting 2026, Chicago, IL, USA, 22 April 2026.
Presented at AAN 2026: International Evaluation of the Aquaporin-4 Antibody Rapid Idot Test. LS1: Late-breaking Science 1. Presented at American Academy of Neurology 2026. April 18-22, Chicago, USA.
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Cite: Late-breaking Science at AAN Annual Meeting 2026: Key trial data across neurology. touchNEUROLOGY. 30 April 2026.
Editor: Katey Gabrysch, Editorial Director.
Disclosures: The content was developed and edited by human editors. No fees or funding were associated with its publication. touchNEUROLOGY utilize AI as an editorial tool (ChatGPT (GPT-4o) [Large language model]. https://chat.openai.com/chat).
This content has been developed independently by Touch Medical Media for touchNEUROLOGY. Views expressed are the speaker’s own and do not necessarily reflect the views of Touch Medical Media.
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