The interim analysis demonstrated a favorable safety and tolerability profile, clear evidence of target engagement and neuroinflammation modulation as measured by translocator protein (TSPO)-PET imaging, and preliminary signals of clinical benefit in a biomarker-selected patient subgroup. The findings support the therapeutic rationale of targeting neuroinflammation in Alzheimer's disease and provide early in vivo evidence that enrupatinib modulates disease-associated neuroinflammatory processes.

Key Interim Data Highlights

• Favorable Safety and Tolerability Profile: No drug-related serious adverse events have been observed to date across all evaluable participants (n=7). Importantly, no clinically significant hepatotoxicity has been reported, potentially differentiating enrupatinib from earlier compounds within the same therapeutic class and supporting its suitability for chronic administration.
• Proof of Target Engagement: Within a biomarker-defined subgroup, 80% (4 out of 5) of participants showed TSPO-PET signal reductions exceeding 30% on average from baseline across multiple prespecified brain regions, with a significant reduction (p < 0.05) in Posterior Cingulate/Precuneus—a magnitude consistent with meaningful target engagement and providing direct in vivo evidence of pharmacodynamic activity. In the broader PET-evaluable population (n=7), 57% of participants also demonstrated reductions in TSPO-PET neuroinflammation signal from baseline following 28 days of oral enrupatinib.
• Early Signals of Cognitive Benefit: One TSPO-PET responder demonstrated marked improvements across all exploratory cognitive and functional assessments, most notably an 8-point increase in MMSE score from baseline. While the study was not designed or powered to evaluate cognitive efficacy at this interim stage, this observation raises the possibility that reducing neuroinflammation may translate into meaningful clinical benefit and merits formal evaluation in larger, controlled trials.
• Biomarker-Guided Precision Medicine Opportunity: A candidate predictive biomarker was identified in preliminary analyses. If validated prospectively, this biomarker may enable patient stratification strategies that improve clinical trial efficiency, enrich for responders, and support a targeted precision medicine approach to AD treatment.

These are exactly the signals we were looking for — clean safety, meaningful target engagement in biomarker-selected patients, and a first glimpse that dampening neuroinflammation can translate to cognitive benefit. Neuroinflammation amplifies amyloid and tau pathology yet has remained largely beyond therapeutic reach — enrupatinib is changing that. We're advancing to a larger, placebo-controlled study with clear momentum.

— Dr. Hung-Kai Kevin Chen, Chief Executive Officer and Chief Medical Officer, Elixiron Immunotherapeutics

Elixiron plans to initiate a placebo-controlled study enriched for likely responders using the predictive biomarker identified in this interim analysis, with the goal of confirming enrupatinib's efficacy in a precision-selected patient population.

About the Study

The Phase 2 proof-of-concept study (NCT06745583) is an ongoing, open-label trial in participants with mild-to-severe Alzheimer's disease. Participants receive enrupatinib 448.2 mg orally twice daily for 28 days, with TSPO-PET as the primary pharmacodynamic endpoint and cognitive and functional assessments as exploratory endpoints. The study is supported in part by the Part the Cloud program (grant PTC-22-973334) from the Alzheimer's Association.

About Enrupatinib (EI-1071)

Enrupatinib is an investigational, brain-penetrant, oral inhibitor of colony-stimulating factor 1 receptor (CSF-1R) designed to modulate microglial-driven neuroinflammation. By targeting CSF-1R, enrupatinib aims to reduce the neuroinflammatory burden that amplifies amyloid and tau pathology in Alzheimer's disease, with potential as a disease-modifying therapy.

About Elixiron Immunotherapeutics

Elixiron Immunotherapeutics is a publicly listed biopharmaceutical company on the emerging stock board of Taipei Exchange (TPEx: 7871), with operations in Cambridge, MA and Taipei, Taiwan. For more information, visit www.elixiron.com.

About the Alzheimer's Association Part the Cloud Award

The Part the Cloud program, funded by the Alzheimer's Association, supports innovative, high-risk/high-reward clinical and translational research aimed at accelerating the development of Alzheimer's disease treatments. Elixiron Immunotherapeutics is a two-time recipient of the Part the Cloud award (grants PTCG-20-706142 and PTC-22-973334). For more information, visit www.alz.org/partthecloud.

Forward-Looking Statements

The interim findings described herein are based on a limited number of subjects and represent preliminary observations from an ongoing clinical study. The trial remains in progress, and final results may differ from those reported in this interim analysis. There can be no assurance that these findings will be replicated in larger studies, that the observed biomarker or clinical effects will translate into meaningful therapeutic benefit, or that enrupatinib will ultimately receive regulatory approval.

This press release contains forward-looking statements regarding the development, clinical potential, regulatory pathway, and future prospects of enrupatinib. These statements are based on current expectations, assumptions, and beliefs and are subject to a number of risks, uncertainties, and other factors that could cause actual results to differ materially. Such risks include, but are not limited to, those associated with clinical development, regulatory review, patient enrollment, clinical outcomes, financing requirements, and other factors beyond the Company's control. The Company undertakes no obligation to update or revise any forward-looking statements, except as required by applicable law.

Contact

Media & Investor Relations
Mr. Chi-Hung HSU
Senior Vice President
Elixiron Immunotherapeutics
ir@elixiron.com
+886-2-2782-7700