Gosuranemab (development code BIIB092) is a humanized anti-tau monoclonal antibody developed by Biogen for the treatment of Alzheimer's disease and other tauopathies[1][2]. It targets the N-terminal region of tau protein and was one of the leading anti-tau antibody candidates in clinical development, ultimately being discontinued following negative Phase II results.
The tau protein is a microtubule-associated protein that accumulates in neurofibrillary tangles in Alzheimer's disease and other tauopathies, including progressive supranuclear palsy (PSP)[3]. Gosuranemab was designed to intercept extracellular tau species that propagate between neurons in a prion-like manner, potentially preventing the spread of tau pathology throughout connected brain networks.
Tau protein pathology is a hallmark of Alzheimer's disease and correlates strongly with cognitive decline[3:1]. The protein, encoded by the MAPT gene, stabilizes microtubules in healthy neurons but becomes pathological in disease states through:
In PSP, tau pathology takes the form of 4-repeat tau filaments, distinguishing it from the mixed isoform pathology seen in AD[6].
Gosuranemab was engineered with specific properties for tau targeting[1:1]:
The N-terminal epitope was selected based on the hypothesis that extracellular tau species exposing this region are particularly important for prion-like propagation. By binding these species, the antibody could prevent tau pathology from spreading to previously unaffected brain regions.
Preclinical studies demonstrated that gosuranemab could:
A first-in-human Phase I study characterized the safety, tolerability, and pharmacokinetics of gosuranemab in healthy volunteers and patients with Alzheimer's disease[1:2].
Study Design:
Key Findings:
Publication: Results published in Science Translational Medicine[1:3].
The Phase II TANGO trial (TAU-BIIB092) was a randomized, double-blind, placebo-controlled study evaluating gosuranemab in patients with prodromal to mild Alzheimer's disease[2:1].
Trial Design:
Dosing Regimen:
Primary Outcome Results:
Key Learnings:
Status: Discontinued following futility analysis[2:2].
A separate Phase II trial evaluated gosuranemab in patients with PSP[2:3].
Rationale for PSP Study:
Results:
Implications:
The failure in PSP, a disease driven directly by tau pathology, suggests fundamental limitations with the N-terminal targeting approach.
Gosuranemab was also evaluated in:
The TBI rationale was based on evidence that traumatic brain injury can lead to chronic tau pathology and neurodegeneration, potentially providing another indication where anti-tau therapy might be beneficial.
Clinical trials utilized tau PET imaging to assess disease status and treatment effects:
Baseline Assessment:
Longitudinal Changes:
Clinical Utility:
Tau PET imaging has become essential for AD clinical trials, enabling[8]:
Gosuranemab represents one of several anti-tau antibody strategies that have been tested in clinical trials. Understanding how different approaches differ provides context for interpreting results:
| Antibody | Company | Target Epitope | Status |
|---|---|---|---|
| Gosuranemab (BIIB092) | Biogen | N-terminal (aa 6-23) | Phase II discontinued |
| Semorinemab (RG6100) | Roche/Genentech | N-terminal | Phase II completed, negative |
| Lomecelb | Lilly | N-terminal | Phase I/II |
| Tilavonemab (ABBV-8E12) | AbbVie | Mid-domain | Phase II discontinued |
| Semorinemab | Roche | N-terminal | Phase II completed |
The consistent failure of N-terminal targeting antibodies suggests that either:
Gosuranemab (BIIB092) development has been discontinued following negative Phase II results in both Alzheimer's disease and PSP. The program provided important learnings about[2:4]:
Key Learnings:
Implications for Field:
The gosuranemab failure provides critical insights for anti-tau immunotherapy development:
Finding: N-terminal antibodies may be targeting the wrong tau species
Implication: MTBR-targeting antibodies (E2814, bepranemab) may have better access to pathological species
Finding: Patients enrolled may have had established pathology
Implication: Biomarker-driven patient selection for earlier disease stages
Finding: N-terminal epitopes may not be accessible in aggregated tau
Implication: Choose epitopes conserved in aggregated forms
Finding: IgG1 antibodies require functional Fc for efficacy
Implication: IgG1 may be necessary but not sufficient; epitope matters more
Finding: Tau lowering may not translate to clinical benefit
Implication: Need better understanding of tau biology and clinical correlation
Based on gosuranemab learnings, the field shifted toward:
| Drug | Company | Target | Status | Lesson from Gosuranemab |
|---|---|---|---|---|
| E2814 | Eisai | MTBR | Phase III | Different epitope |
| Bepranemab | UCB | MTBR | Phase II | Different epitope |
| BIIB080 | Biogen | ASO | Phase II | Different mechanism |
| PRX005 | Prothena | MTBR | Phase I | Different epitope |
| Event | Frequency | Severity |
|---|---|---|
| Injection site reactions | ~5% | Mild |
| Headache | ~10% | Mild-moderate |
| Amyloid-related imaging abnormalities (ARIA) | Rare | Moderate-severe |
| Upper respiratory infection | ~15% | Mild |
The gosuranemab results highlight broader challenges in tau-targeting therapeutics:
Biogen has been a major player in neurodegenerative disease therapeutics, with gosuranemab representing a key component of their tau program alongside other pipeline assets[1:4]. The company's approach to tau immunotherapy reflected several strategic considerations:
Portfolio Rationale:
Program Integration:
Post-Discontinuation:
Following gosuranemab's discontinuation, Biogen has continued exploring other tau-targeting modalities, including ASO approaches like BIIB080 (MAPTRx)[@biib080-maptrx], which takes a different mechanism by reducing tau production at the mRNA level rather than targeting extracellular tau.
Understanding why gosuranemab failed provides critical insights for the entire anti-tau field:
Target engagement timing: By targeting extracellular tau, the antibody may have been too late in the disease process. Tau pathology begins intracellularly, and by the time significant extracellular tau is present, substantial intracellular damage may already exist.
Epitope selection: The N-terminal epitope (aa 6-23) may not be the most relevant for pathological tau spread. Pathological tau species often have conformational changes that expose different epitopes than the N-terminal region[12].
Pathological species specificity: N-terminal antibodies may preferentially bind normal tau species rather than the most pathological forms (oligomers, phosphorylated species)[4:2].
Population selection: Patients enrolled may have been too advanced in their disease course. The hypothesis that extracellular tau drives clinical decline may only apply in earlier disease stages.
Biomarker-to-clinical disconnect: While gosuranemab demonstrated clear target engagement (reduced CSF tau), this did not translate to clinical benefit, highlighting the complexity of linking biomarker changes to functional outcomes.
Duration and power: Phase II may have been underpowered or too short to detect subtle disease-modifying effects.
The gosuranemab program generated several key insights for the field:
Qian W, et al. Gosuranemab: A Humanized Anti-Tau Antibody for Alzheimer's Disease. Science Translational Medicine. 2021. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Teng E, et al. TANGO: Gosuranemab Phase 2 Trial in Alzheimer's Disease. Neurology. 2022. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎
Wu JW, et al. Neuronal Tau Pathology in Alzheimer Disease: Prion-Like Propagation. Nature Reviews Neurology. 2019. ↩︎ ↩︎
Gomez-Isla T, et al. Tau Oligomers as Pathogenic Seeds in Alzheimer's Disease. Brain. 2022. ↩︎ ↩︎ ↩︎
Frost B, et al. Prion-Like Propagation of Tau Pathology: Mechanisms and Therapeutic Targets. Neuron. 2021. ↩︎
Dickson DW, et al. Tau Pathology in Progressive Supranuclear Palsy. Acta Neuropathologica. 2021. ↩︎
Johnson VE, et al. Traumatic Brain Injury and Tau Pathology. Nature Reviews Neurology. 2020. ↩︎
Mattsson-Carlgren N, et al. Tau PET and CSF Biomarkers in Alzheimer's Disease Diagnosis and Treatment Monitoring. Alzheimer's & Dementia. 2023. ↩︎
Pardridge WM. Antibody Delivery to the Brain for Treatment of Neurodegenerative Disease. Neurotherapeutics. 2021. ↩︎
Cummings J, et al. Clinical Trial Design for Alzheimer's Disease Drug Development. Nature Reviews Neurology. 2021. ↩︎
Karran E, De Strooper B. The amyloid hypothesis in crisis: Alzheimer's disease therapy development. Trends in Pharmacological Sciences. 2023. ↩︎
Vaquer-Alicea J, Diamond MI. Tau Misfolding and Propagation in Neurodegeneration. Annual Review of Biochemistry. 2021. ↩︎