Therini Bio, Inc., a Sacramento-based clinical-stage biotech company, announced on May 14, 2025, that it has secured $39 million in Series A extension financing to advance its pipeline of fibrin-targeting immunotherapies for neurodegenerative diseases. This extension brings the company's total Series A funding to $75 million, following an initial $36 million raise.
The financing round welcomed new investors Angelini Ventures and Apollo Health Ventures, alongside existing backers including SV Health Investors' Biotech Fund, Dementia Discovery Fund, MRL Ventures Fund, Sanofi Ventures, Eli Lilly and Company, Dolby Family Ventures, and Foundation for a Better World.
Novel Approach to Neurodegeneration
Therini Bio is pioneering a distinctive approach to neurodegenerative diseases by targeting vascular dysfunction, a key underlying factor in conditions like Alzheimer's Disease (AD) and Diabetic Macular Edema (DME). The company's scientific platform focuses on addressing toxic fibrin deposits that form outside blood vessels due to vascular damage.
These fibrin deposits trigger chronic neuroinflammation, which ultimately leads to neuronal damage and progression of neurodegenerative diseases. By specifically targeting the inflammatory epitope on fibrin, Therini's therapeutic approach aims to halt the destructive cascade of neuroinflammation without interfering with normal coagulation processes.
"Factors such as aging, genetics, and prevalent diseases like hypertension and diabetes lead to vascular dysfunction and the accumulation of toxic fibrin deposits," explained Tara Nickerson, Ph.D., Chief Executive Officer of Therini Bio. "Our approach targets the root cause rather than just managing symptoms."
THN391: Lead Candidate Shows Promise
The company's lead candidate, THN391, is a potential first-in-class, high-affinity humanized monoclonal antibody designed to selectively block fibrin-mediated neuroinflammation. Importantly, it does this without affecting coagulation pathways, a critical safety consideration for any therapy targeting components of the clotting system.
In preclinical studies, THN391 demonstrated activity in preventing vascular and neuronal degeneration in models of Alzheimer's Disease and retinal diseases. The compound recently completed a Phase 1a trial in healthy volunteers with encouraging results:
- Well-tolerated safety profile
- No adverse hematological effects
- No impact on coagulation and fibrinolysis
- Absence of anti-drug antibody response
- Dose-proportional pharmacokinetics
- Half-life supporting monthly dosing
Advancing to Phase 1b Trials
With the new funding, Therini Bio plans to initiate Phase 1b trials evaluating THN391 in patients with Alzheimer's Disease and Diabetic Macular Edema. The company will also support the development of a fibrin/VEGF bispecific antibody, expanding its pipeline of potential treatments.
"We are deeply grateful to partner with such a distinguished investor group, both new and old," said Dr. Nickerson, who previously served as Chief Business Officer at Maze Therapeutics and Prothena Biosciences. "Their support enables us to significantly advance our shared vision of delivering patients a rational, innovative approach to potentially treat their debilitating conditions. We look forward to advancing the Phase 1b trials to demonstrate the potential benefit of this novel mechanism in patients."
Investor Enthusiasm
The investment reflects growing interest in novel approaches to neurodegenerative diseases, particularly those addressing underlying vascular and inflammatory mechanisms rather than focusing solely on protein aggregates like amyloid or tau.
Thomas Thestrup, Senior Principal at Angelini Ventures, who led the investment on behalf of his firm, expressed enthusiasm about Therini's approach: "We are proud to support Therini Bio's mission to address the underlying vascular and inflammatory drivers of neurodegenerative disease through a truly novel approach. As an active CNS investor, we are excited about Therini's first-in-class selective antibody therapy targeting fibrin-mediated inflammation, offering a groundbreaking path to transform the treatment of diseases such as Alzheimer's and DME."
Market Context and Unmet Need
Neurodegenerative diseases represent a significant global health burden with limited effective treatment options. Alzheimer's Disease alone affects approximately 6.7 million Americans, with numbers expected to triple by 2060 without effective interventions. Similarly, Diabetic Macular Edema affects about 7% of people with diabetes and is a leading cause of vision loss in working-age adults.
Current treatments for these conditions either provide symptomatic relief or target specific pathological features without addressing underlying vascular dysfunction. Therini's approach represents a potential paradigm shift in treating these devastating diseases by targeting a common pathological mechanism across multiple neurodegenerative conditions.
A Distinctive Therapeutic Strategy
Therini Bio's therapeutic strategy stands out in the neurodegenerative disease landscape by focusing on the role of vascular dysfunction and fibrin-mediated neuroinflammation. While many companies target protein aggregates like amyloid-beta or tau in Alzheimer's Disease, Therini's approach addresses a different but potentially crucial pathological mechanism.
The company's selective targeting of the inflammatory epitope on fibrin, without affecting coagulation, represents a careful balancing act that could potentially offer therapeutic benefits without the bleeding risks typically associated with anti-coagulant approaches.
As Therini Bio advances its clinical programs, the neuroscience community will be watching closely to see if this novel approach can translate into meaningful benefits for patients with these challenging and devastating conditions.
