Olaptesed pegol (NOX-A12) is a PEGylated RNA Spiegelmer (L-ribonucleic acid aptamer) that specifically binds to the chemokine CXCL12 and inhibits the binding of CXCL12 to CXCR4 and CXCR7, thereby inhibiting the angiogenesis and metastasis from assisting the cancer treatment. Here, CXCL12 is linked to cancer.