Foselutoclax
Foselutoclax (UBX1325)
Also known as: UBX1325
The most advanced senolytic in humans: an injected BCL-xL inhibitor that matched the biologic aflibercept on vision at most timepoints in a Phase 2b for diabetic macular edema.
Overview
Foselutoclax (Unity Biotechnology) kills senescent cells by blocking BCL-xL, the survival protein those cells depend on. Given as an eye injection, it improved vision by 5 or more letters at weeks 24 and 36 in the ASPIRE Phase 2b and was non-inferior to aflibercept at 9 of 10 timepoints, though investors judged the result mixed. The earlier BEHOLD trial was published in NEJM Evidence. It is the clearest proof that a senolytic can produce a clinical effect in people.
Mechanism of action
Inhibition of BCL-xL removes the anti-apoptotic signal senescent cells rely on, inducing their selective death.
Key studies & citations
- Human2025
UBX1325 in diabetic macular edema (BEHOLD)
Vision gains sustained through 48 weeks after a single injection.
NEJM Evidence - Human2025
UNITY announces complete 36-week results from the ASPIRE Phase 2b study
Head-to-head against aflibercept.
Unity Biotechnology press release
Frequently asked questions
Why is a senolytic being tested in the eye?
The eye is a contained compartment where a local injection can reach senescent cells without systemic exposure, making it a practical first proving ground.
Can I take a senolytic like this?
No. Foselutoclax is an investigational injectable used only in trials. Oral senolytics such as dasatinib plus quercetin or fisetin are a different, less-proven category.