FOXO4-DRI
Retro-inverso D-amino acid peptide that disrupts the FOXO4-p53 nuclear interaction in senescent cells, restoring apoptotic capacity and selectively clearing senescent cell burden. Experimental compound with animal model evidence only.
Overview
Key Properties
| Property | Value |
|---|---|
| Type | D-retro-inverso peptide |
| Length | 34 amino acids |
| Stability | High — protease resistant (D-form) |
| Target | FOXO4-p53 nuclear interaction |
| Selectivity | p21-high senescent cells |
| Status | Experimental Only |
Evidence Landscape
| Model | Finding |
|---|---|
| Mouse (fast aging) | Positive — de Keizer 2017 |
| Mouse (chemotherapy) | Restored fur/fitness |
| Mouse (obesity) | Reduced NAFLD markers |
| Human cell lines | In vitro selectivity shown |
| Human clinical | No data |
Mechanism of Action
Senescent Cell Pathway (Target)
| Step | Action |
|---|---|
| 1. Senescence state | p21/p16 upregulated, DNA damage foci |
| 2. FOXO4 nuclear retention | FOXO4 binds p53, prevents apoptosis |
| 3. SASP secretion | IL-6, IL-8, MMP-3 inflammatory factors |
| 4. FOXO4-DRI binding | Competitively displaces p53 from FOXO4 |
| 5. p53 liberation | p53 activates Puma/NOXA → mitochondrial apoptosis |
| 6. Senescent cell clearance | Selective removal of p21-high cells |
Downstream Effects (Mouse Data)
| Effect | Observation |
|---|---|
| Physical fitness | Improved exercise capacity and fur density |
| Tissue regeneration | Reduced liver fat, improved kidney markers |
| Inflammatory markers | Reduced circulating IL-6, TNF-alpha |
| Lifespan | Trend toward extension (not powered for significance) |
| p21 clearance | Reduced SA-β-gal positive cells in liver/kidney |
Senolytic Comparison
FOXO4-DRI
- FOXO4-p53 competitive inhibitor
- D-retro-inverso — protease resistant
- Selective for p21-high cells (preclinical)
- No thrombocytopenia in mice
- Grade C+ — 1 landmark mouse study
Dasatinib + Quercetin
- BCR-Abl / PI3K pathway inhibition
- Oral administration, broader targets
- Human Phase 1/2 data available
- GI side effects common
- Most human-validated senolytic combo
Navitoclax (ABT-263)
- Bcl-2/Bcl-xL inhibitor (BH3 mimetic)
- Strong preclinical senolytic evidence
- Causes significant thrombocytopenia
- Platelet apoptosis limits clinical use
- Moved toward oncology applications
Research Protocol
Animal → Human Equivalent Dose (HED) Calculation
| Parameter | Mouse (de Keizer 2017) | Human Extrapolation |
|---|---|---|
| Effective dose | 5 mg/kg × 3×/week × 3 weeks | ~0.4 mg/kg HED (÷12.3 factor) |
| For 80 kg subject | — | ~32 mg per administration |
| Route | IP (intraperitoneal) | SubQ or slow IV |
| Cycle | 3 weeks continuous | 3–5 pulsed administrations |
Extrapolated Human Research Protocols
| Protocol | Dose | Frequency | Duration | Notes |
|---|---|---|---|---|
| Conservative Pulse | 1 mg/kg SubQ | Weekly × 3 | 3 doses total | Minimal exposure, first exploration |
| Moderate Pulse | 2 mg/kg SubQ | 2× weekly × 2 weeks | 4 doses total | Closer to HED range |
| Monthly Maintenance | 1–2 mg/kg | Once monthly | Ongoing | Speculative maintenance approach |
| Intensive (Animal-matched) | 3–5 mg/kg | 3× weekly × 3 weeks | 9 doses total | Closest to de Keizer protocol |
Note: All human dosing above is speculative extrapolation from animal data. FOXO4-DRI is not approved for human use. Run intermittent pulse cycles — not continuous — given the senolytic mechanism of action.
Reconstitution Calculator
Calculate per-dose volume based on body weight, dose, and vial concentration.
Side Effects & Safety Profile
Clinical Evidence
Evidence base is limited to a single landmark publication and supporting in vitro work. No clinical trials have been registered or completed for FOXO4-DRI in humans.
| Study | Key Finding | Grade |
|---|---|---|
| de Keizer et al. 2017PMID 28340339 | FOXO4-DRI (5 mg/kg 3×/wk) cleared senescent cells in fast-aging and chemotherapy-treated mice; restored fitness, fur, kidney function; no overt toxicity observed | C+ — Animal only |
| de Keizer et al. 2017PMID 28340339 | In vitro: FOXO4-DRI selectively induced apoptosis in p21-high human IMR90 senescent cells vs proliferating controls | C+ — In vitro |
| Baar et al. 2017Related commentary | FOXO4-p53 interaction confirmed as key anti-apoptotic mechanism in multiple senescent cell types; target validation | C+ — Mechanistic |
No registered clinical trials found on ClinicalTrials.gov for FOXO4-DRI as of April 2026. This compound has not advanced to IND or Phase 1 studies.
Stacking Strategies
FOXO4-DRI addresses cellular senescence — one of the primary hallmarks of aging. Complementary stacks cover other hallmarks. Run FOXO4-DRI in short pulse cycles, not concurrent with all compounds.
Frequently Asked Questions
What is FOXO4-DRI and how does it work as a senolytic?
FOXO4-DRI is a retro-inverso D-amino acid peptide. In senescent cells, FOXO4 binds p53 in the nucleus to prevent apoptosis. FOXO4-DRI competitively disrupts this interaction, releasing p53 to activate Puma/NOXA apoptotic programs, selectively killing senescent cells while theoretically sparing healthy cells where the FOXO4-p53 interaction is not present.
What is the experimental dosing for FOXO4-DRI?
Based on the de Keizer 2017 mouse study (5 mg/kg × 3×/week × 3 weeks), using FDA allometric scaling (÷12.3), the human equivalent dose is approximately 0.4 mg/kg. For an 80 kg subject, this approximates ~32 mg per administration. Community protocols range from 1–5 mg/kg with 3–5 intermittent pulse doses, but no human data validates any of these extrapolations.
How does FOXO4-DRI differ from dasatinib/quercetin?
Dasatinib/quercetin (D+Q) is the most human-validated senolytic combination with Phase 1/2 trial data. FOXO4-DRI claims higher selectivity via its mechanism-specific FOXO4-p53 targeting, versus D+Q's broader kinase and antioxidant pathways. However, D+Q has actual human safety data; FOXO4-DRI does not.
Is FOXO4-DRI safe for human use?
No formal human safety data exists. The mouse study did not report significant toxicity at effective doses. However, extrapolating animal tolerability to humans is unreliable, and the experimental nature of senolytic therapy means unknown risks remain. This compound carries the highest risk level among the peptides on this platform.
Can FOXO4-DRI be stacked with Epithalon?
Conceptually yes — they are complementary. FOXO4-DRI clears existing senescent cells; Epithalon (via telomerase activation) slows formation of new senescent cells. Run in sequential cycles rather than concurrent dosing, and allow recovery time between FOXO4-DRI pulse doses.
