New Findings From Sunbird Bio Reveal Significant Potential of Specific Tau Proteins to Serve as Blood-Based Biomarker for Alzheimer's Disease

Sunbird Bio, a biotechnology company developing proprietary protein- and blood-based technologies to improve diagnosis and treatment of neurological disorders and early-stage cancer, today announced new findings revealing a significant correlation between heightened levels of extracellular vesicle (EV)-bound tau proteins in blood and the presence of Alzheimer's disease-associated tau tangles in the brain, as validated by positron emission tomography (PET) imaging. Results from the study will be shared tomorrow in a poster presentation at the Tau2024 Global Conference.

"These results validate the potential of EV-bound tau proteins to serve as reliable blood-based biomarkers in accurately detecting Alzheimer's disease," said John McDonough, executive chair and CEO of Sunbird Bio. "This confirmed correlation between EV-bound tau in the blood and tau tangles in the brain combined with the early validation of our new tau assays is incredibly exciting. It means we can take the next step toward initiating more robust studies evaluating the capabilities of our APEX diagnostic in detecting EV-bound tau to potentially provide earlier detection of neurological diseases."

Alzheimer's disease is marked by the accumulation of misfolded proteins in the brain, notably amyloid beta (A?) and tau, leading to cognitive decline. In Alzheimer's, tau becomes hyperphosphorylated, misfolding and forming tangles within neurons, disrupting their function and contributing to their degeneration. When the aggregated proteins bind to nanoscale EVs in the brain, scarce levels are able to pass through the blood-brain barrier into the bloodstream. These EV-bound particles are difficult for most blood tests to accurately detect.

The Sunbird Bio study being shared at Tau2024 evaluated the potential of EV-bound tau proteins in the blood as a method of directly detecting the tau proteins that aggregate in the brain. Researchers prospectively collected blood samples from 10 individuals who were tau-PET positive, as well as from 22 age-matched healthy individuals. They then used Sunbird Bio's new proprietary tau assays to distinguish between EV-bound and unbound soluble forms of tau in plasma. Results suggest that unbound soluble tau was unable to classify PET-positive samples, while blood-based brain EV-bound tau accurately classified tau-PET positive samples with an area under the curve (AUC) of 0.93, and blood-based brain EV-bound phosphorylated tau (pTau) accurately classified tau-PET positive samples with an AUC of 0.90. These preliminary findings suggest that Sunbird Bio's blood-biomarker signatures, consisting of multiple forms of tau bound to specific types of brain-derived EVs, have the potential to accurately and directly detect tau aggregation in the brain via blood test.

"In contrast to soluble forms of proteins, the superior sensitivity and specificity of EV-bound biomarkers observed in studies to date underscore their potential as a reliable and accessible diagnostic marker for distinguishing individuals with tau pathology," said Huilin Shao, Ph.D., founder of Sunbird Bio. "The findings we're sharing are particularly notable for us given that we developed our APEX technology to detect EV-bound proteins that aggregate, cross the blood-brain barrier and denote the presence of neurological conditions such as Alzheimer's disease and Parkinson's disease. If we're able to identify these pathological signatures sooner, it creates the possibility to diagnose disease earlier and pave the way for patients to access new therapies that could potentially alter the trajectory of these devastating disorders."

The results shared at Tau2024 reinforce the expanded potential of Sunbird Bio's protein-based APEX diagnostic platform to overcome the limitations of PET, cerebrospinal fluid (CSF)-based tests and other blood-based diagnostics. APEX uses a proprietary sensor platform and optical amplification to directly detect and measure very low concentrations of EV-bound, aggregated proteins in blood. The company plans to initiate a larger clinical study to further validate its tau blood-biomarker signatures and has an active pipeline that includes protein- and blood-based tests for A?, tau, alpha synuclein and other biomarkers for neurological diseases.

Sunbird Bio is actively securing partnerships with biopharma companies and others to accelerate the development of its APEX platform and conduct clinical studies; use cases include longitudinal monitoring, patient stratification and target engagement.

About Sunbird Bio

Sunbird Bio is a biotechnology company developing proprietary protein- and blood-based diagnostic tests that provide unprecedented insights to enable earlier, more accurate diagnosis and treatment of neurological disorders and early-stage cancer. Sunbird's innovative technologies uniquely detect the property and activity of proteins to empower researchers and clinicians with actionable information that is not available or accessible from current tests. Sunbird Bio's unparalleled leadership in protein- and blood-based diagnostics positions the company to become a global leader in the field, addressing significant research and clinical gaps, and serving multiple, sizable markets. For more information, please visit sunbirdbio.com.