Balixafortide
Balixafortide, formerly POL6326, is a cyclic peptide inhibitor of CXCR4 investigated in oncology combinations. Its clinical and preclinical combination studies are distinct.
At a glance
- Evidence stage
- Early human
- Regulatory status
- Investigational; the phase 3 FORTRESS breast-cancer program failed its reported response endpoint and was subsequently closed.
- Research context
- Balixafortide, formerly POL6326, is a cyclic peptide inhibitor of CXCR4 investigated in oncology combinations. Its clinical and preclinical combination studies are distinct.
What this is
- Balixafortide, formerly POL6326, is a cyclic peptide inhibitor of CXCR4 investigated in oncology combinations. Its clinical and preclinical combination studies are distinct.
What this isn't
- A recommendation to use, prepare, combine, or administer a product
- Evidence that a related molecule or a differently formulated product has the same effects
Key terms
Balixafortide, formerly POL6326, is a cyclic peptide inhibitor of CXCR4 investigated in oncology combinations. Its clinical and preclinical combination studies are distinct.
CXCR4 signaling influences movement and organization of cancer and immune cells. Balixafortide aims to alter that tumor environment. A 2025 mouse study described inverse-agonist activity and investigated combination with an anti-PD-1 antibody. The biological rationale is specific to that model and partner therapy, rather than evidence that CXCR4 inhibition broadly improves cancer outcomes.
Evidence limits
How to read the evidence
The subsequent prospectus records closure of FORTRESS. Both development reports are sponsor-authored and should be identified as such. The newer preclinical work supports a testable hypothesis, not an established treatment or survival benefit in people. A useful guide must preserve the negative phase 3 result instead of presenting only the latest mechanistic findings.
Sources appraised 2026-10-28. Educational information; not medical advice. Study findings apply to the populations, preparations and outcomes described.
External sources and citations
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