CXCL12 and lymphoid leukemia: Finally, there is one CXCL12 antagonist, olaptesed pegol (NOX-A12), a pegylated structured L-oligoribonucleotide that binds and neutralizes CXCL12, which is in a phase 2a study of relapsed and refractory lymphocytic leukemia (NCT01486797) [132].