1. KLRS's TH103 shows significant visual acuity improvements in Phase 1a trials. 2. The therapy's pharmacokinetics indicate effective intraocular retention over current treatments. 3. Initial findings suggest potential for extended treatment durability and reduced patient burden. 4. Conference call scheduled to discuss promising Phase 1a data insights.
FAQ
Why Bullish?
Positive data from TH103 trials suggests strong efficacy and patient adherence, reminiscent of successful drug launches like Eylea, benefiting KLRS.
How important is it?
The encouraging efficacy data is likely to enhance KLRS's market position in retinal disease treatments, driving stock interest.
Why Long Term?
The accelerated development timeline to Phase 3 pending better results implies sustained interest and valuation increases over time.
Kalaris Therapeutics Reports Positive Initial Phase 1a Data for TH103 in Treatment-Naïve Neovascular AMD
BERKELEY HEIGHTS, N.J., Dec. 17, 2025 (GLOBE NEWSWIRE) — Kalaris Therapeutics, Inc. (NASDAQ: KLRS), a clinical-stage biopharmaceutical company focused on developing treatments for common retinal diseases, has announced promising initial results from its Phase 1a trial of TH103. This trial investigates a fully humanized recombinant fusion protein that targets VEGF as a decoy receptor in treatment-naïve patients suffering from neovascular age-related macular degeneration (nAMD).
Key Findings from the Phase 1a Trial
The initial data reveal that TH103 achieved significant improvements in visual acuity and anatomical structure after just one injection. Key outcomes include:
- Mean 10-letter gain in best-corrected visual acuity (BCVA)
- Mean 129 μm reduction in central subfield thickness (CST)
- Approximately 95% reduction in central subfield intraretinal fluid (IRF)
These results are expected to be presented during a conference call today at 4:30 PM EST.
TH103: Engineered for Enhanced Potency
TH103, developed by Dr. Napoleone Ferrara, a co-founder of Kalaris, is designed for extended intraocular retention and increased efficacy in inhibiting VEGF. Preclinical studies have shown that TH103 binds more effectively to heparan sulfate proteoglycans (HSPG) and clears from the circulation more slowly than current leading agents, suggesting that it may offer longer-lasting results.
Initial Data Supports Clinical Efficacy
The Phase 1a trial involved thirteen treatment-naïve nAMD patients who received varying dosages of TH103 (0.5 mg, 1.5 mg, and 2.5 mg) and underwent six months of follow-up. The findings support the hypothesis that TH103 offers substantial visual and anatomical improvements, confirming its potential clinical benefits.
Dr. Ferrara stated, "These initial Phase 1a data are highly encouraging and validate the molecular engineering approach we pursued in developing TH103."
Tolerability and Safety of TH103
TH103 was generally well tolerated among participants:
- No dose-limiting toxicities (DLTs) reported
- No serious adverse events (SAEs) related to TH103 observed
- No instances of retinal vascular occlusion, retinal vasculitis, cataracts, or elevated intraocular pressure
While two cases of mild to moderate intraocular inflammation were noted, subsequent changes in the manufacturing process alleviated these issues, prompting Kalaris to advance with the revised product for future trials.
Clinical Implications and Future Directions
The pharmacokinetic profile of TH103 demonstrates a 27 to 51-fold lower plasma Cmax than current anti-VEGF therapies, indicating significant intraocular retention and minimal systemic exposure. Additionally, a retreatment analysis revealed that 31% of patients did not require further anti-VEGF treatment, suggesting the potential for prolonged efficacy following a single injection.
Andrew Oxtoby, CEO of Kalaris, added, "These data are consistent with preclinical studies and support our expectations based on TH103's molecular design."
In light of these encouraging findings, Kalaris is moving forward with a Phase 1b/2 study to further explore different dosing regimens and potentially set the stage for Phase 3 trials by the second half of 2026.
Conference Call and Further Information
Interested parties can listen to the live conference call with Kalaris management today at 4:30 PM EST by dialing 1-877-407-0784 or by participating in the webcast here. The event will include a slide presentation and a Q&A session.
About Neovascular Age-Related Macular Degeneration
Neovascular AMD is a major cause of vision loss in individuals over 50, impacting millions globally. The condition leads to abnormal blood vessel growth in the retina, resulting in fluid leakage and progressive vision impairment. Although anti-VEGF therapies have significantly improved patient outcomes, many individuals face restrictions due to the need for frequent injections, which can affect treatment adherence.
About Kalaris Therapeutics
Kalaris Therapeutics, recognized for its commitment to retinal disease treatment, is advancing novel therapies underpinned by the pioneering work of Dr. Napoleone Ferrara. As a leader in clinical-stage biopharmaceutical development, Kalaris is dedicated to addressing unmet medical needs with innovative solutions. To learn more, visit www.kalaristx.com.
Forward-Looking Statements
This communication includes forward-looking statements as defined by the U.S. Private Securities Litigation Reform Act of 1995, which are subject to risks and uncertainties that could affect Kalaris Therapeutics' strategies and future operations.