SPX5551

SPX5551 (also known as POL5551) is a potent, selective peptidomimetic macrocycle that acts as an antagonist of the C-X-C motif chemokine receptor 4 (CXCR4). Developed by Spexis (formerly Polyphor), it is a structural analogue of balixafortide (POL6326). SPX5551 disrupts the CXCR4/CXCL12 axis, which is a key pathway involved in tumor cell survival, migration, and resistance to chemotherapy within the tumor microenvironment. Preclinical studies have demonstrated that SPX5551 can enhance the anti-tumor activity of conventional and targeted therapies, such as ibrutinib, copanlisib, and rituximab, particularly in B-cell lymphomas like mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL). It has also shown potential in overcoming resistance to BTK and PI3K inhibitors by inhibiting pro-survival signaling pathways such as AKT and NF-κB.

Other names

POL5551POL-5551POL 5551