Rankings / Longevity — Senolytics & Polyphenols

Foselutoclax (UBX1325)

Longevity · Senolytic (Bcl-xL inhibitor)

Tier C-

Reviewed by Read Off Label · Last reviewed · How we grade

senolyticinvestigational
4.1 / 10
Tier C-
Ev 4 Bn 2 Sf 5

Bottom line

Read Off Label grades Foselutoclax (UBX1325) as C- (4.1/10) based on mixed evidence, low benefit magnitude, and a med-risk safety profile.

The most informative human test the senolytic idea has had — and not the clean win it is often summarized as.

Studied, labeled, or reported-use context: Intravitreal injection, 10 µg; ASPIRE dosed at randomization then every 8 weeks over 6 months — Investigational; not individualized guidance.

What the evidence says

The most informative human test the senolytic idea has had — and not the clean win it is often summarized as. ASPIRE (Phase 2b, n=52, randomized, double-masked, active-controlled) put foselutoclax against aflibercept, the standard of care, in diabetic macular edema. Its pre-registered primary endpoint was the mean change in visual acuity averaged over weeks 20 and 24 — and that is precisely the endpoint where non-inferiority was not met, while 9 of 10 other timepoints through week 36 came out comparable. Coverage emphasizing the 9 obscures which one was primary. The vision gains were real but were not shown to match an existing drug. Unity then cut its whole workforce in May 2025, moved its executives to consulting roles and started exploring a sale, license or winddown, so the program stalled for financial reasons rather than a safety signal. Earlier studies, all completed: Phase 1 (n=19, DME), Phase 2 BEHOLD (n=65, DME) and a Phase 2 in neovascular AMD (n=51). Two points matter for the wider senolytic class. First, the strongest clinical test of clearing senescent cells had to be injected directly into the eye because systemic Bcl-xL inhibition drops platelets — local delivery is a constraint of the mechanism, not a trial-design preference. Second, even with that advantage it did not beat standard care. Industry-sponsored throughout.

Mechanism

Small-molecule Bcl-xL inhibitor. Senescent cells depend on Bcl-xL to stay alive, so blocking it pushes them into apoptosis while sparing normal cells. Given by injection into the eye so the senolytic effect stays local to the retina — systemic Bcl-xL inhibition causes dose-limiting thrombocytopenia

Studied, labeled, or reported dose & route

Intravitreal injection, 10 µg; ASPIRE dosed at randomization then every 8 weeks over 6 months

This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.

Citations

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Common questions

What does the evidence show about Foselutoclax (UBX1325)'s effects?
Read Off Label rates the evidence for Foselutoclax (UBX1325) as Mixed and the benefit magnitude as low, producing an overall grade of C- (4.1/10). The most informative human test the senolytic idea has had — and not the clean win it is often summarized as.
What safety findings are reported for Foselutoclax (UBX1325)?
Foselutoclax (UBX1325) has a med risk profile in the database. Med (intravitreal injection carries endophthalmitis, intraocular inflammation and retinal-detachment risk; systemic Bcl-xL inhibition causes thrombocytopenia, which is why the drug is delivered locally) Legal status: Investigational (Phase 2 complete; program shelved — Unity Biotechnology cut its entire workforce in May 2025 and began exploring sale, licensing or dissolution).
What doses or routes are reported for Foselutoclax (UBX1325)?
Intravitreal injection, 10 µg; ASPIRE dosed at randomization then every 8 weeks over 6 months This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
How does Foselutoclax (UBX1325) work?
Small-molecule Bcl-xL inhibitor. Senescent cells depend on Bcl-xL to stay alive, so blocking it pushes them into apoptosis while sparing normal cells. Given by injection into the eye so the senolytic effect stays local to the retina — systemic Bcl-xL inhibition causes dose-limiting thrombocytopenia

This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.