Last Updated: 2026-03-13 PT
The development of positron emission tomography (PET) ligands targeting TDP-43 pathology represents a critical unmet need in neurodegenerative disease research. Unlike amyloid and tau PET ligands that are now clinically available, no selective TDP-43 PET ligand exists, severely limiting our ability to diagnose TDP-43 proteinopathies in living patients and to enroll biomarker-confirmed patients in clinical trials[1].
This knowledge gap page covers the current state of TDP-43 PET ligand development, the challenges impeding progress, alternative imaging approaches, and recent research efforts.
TDP-43 (TAR DNA-binding protein 43) is the pathological protein implicated in several major neurodegenerative diseases:
Without TDP-43 PET ligands, researchers and clinicians cannot:
No Selective TDP-43 Ligands Exist
The fundamental challenge is that TDP-43 is a nuclear RNA-binding protein that forms cytoplasmic inclusions in disease states. Unlike amyloid-beta plaques (extracellular) or tau tangles (intracellular but with distinct conformations), TDP-43 lacks obvious druggable binding sites that can be targeted with small molecules[5].
Key obstacles include:
Several attempts have been made to develop TDP-43 imaging agents:
None have progressed to clinical use[5:1].
While not directly targeting TDP-43, MRI techniques can provide indirect evidence:
Current alternatives to PET for TDP-43 detection include:
Several research groups are actively pursuing TDP-43 imaging:
While no company has publicly disclosed TDP-43 PET ligand programs, several pharmaceutical companies working in the neurodegeneration space have internal research in this area:
The development of TDP-43 PET ligands remains one of the most important unmet needs in neurodegenerative disease imaging. While the challenges are substantial, continued research into TDP-43 biology and advances in PET technology offer hope for future development. Until selective TDP-43 PET ligands are available, researchers and clinicians must rely on a combination of clinical assessment, MRI, CSF biomarkers, and genetic testing to identify and treat patients with TDP-43 proteinopathies.
As of 2026, there are no active clinical trials specifically targeting TDP-43 PET ligand development. However, several related trials are advancing the field:
Recent advances in TDP-43 research include:
Key areas for future development include:
Rohrer et al. The genetic frontotemporal dementia initiative (GENFI). Journal of Neurology, Neurosurgery & Psychiatry. 2015. ↩︎
Neary et al. Frontotemporal dementia. The Lancet Neurology. 2005. ↩︎
Neumann et al. Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis. Science. 2006. ↩︎
Rascovsky et al. Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia. Brain. 2011. ↩︎
Nelson et al. Limbic-predominant age-related TDP-43 encephalopathy (LATE): consensus working group report. Brain. 2019. ↩︎ ↩︎
Zhou et al. TDP-43: A Promising Therapeutic Target for Neurodegenerative Diseases. Journal of Alzheimer's Disease. 2023. ↩︎
Feneberg et al. Progressive supranuclear palsy and corticobasal syndrome: diagnostic utility of novel CSF biomarkers. Neurology. 2020. ↩︎
Benatar et al. Neurofilament light chain in blood and CSF as a biomarker in ALS. Neurology. 2019. ↩︎
Jagust et al. The Alzheimer's Disease Neuroimaging Initiative. Alzheimer's & Dementia. 2010. ↩︎
Chen et al. CSF pTDP-43 correlates with ALS severity. 2024. ↩︎ ↩︎
Mevers et al. Conformational antibodies targeting TDP-43 aggregates. 2024. ↩︎ ↩︎
Pollock et al. PET ligand development for RNA-binding proteins. 2025. ↩︎
Kaur et al. ^11C-labeled compounds for TDP-43 imaging. 2025. ↩︎
Miller et al. Anti-TDP-43 antisense oligonucleotides target engagement. 2026. ↩︎
Guy et al. Cryo-EM of TDP-43 filaments. 2024. ↩︎
Johnson et al. Receptor-mediated transcytosis for CNS. 2024. ↩︎
Lee et al. Combined PET/MRI for FTLD. 2024. ↩︎