NEW YORK – X4 Pharmaceuticals has initiated a early-phase safety study of mavorixafor and ibrutinib (AbbVie's Imbruvica) for patients with CXCR4-mutated Waldenström’s macroglobulinemia (WM), a rare type of non-Hodgkin's lymphoma.
The Phase Ib dose-escalation study will evaluate the safety and tolerability of mavorixafor plus ibrutinib in patients with WM who have a gain-of-function mutation in CXCR4, in addition to the MYD88 mutation that shows up in 90 percent of WM. Between 30 percent and 40 percent of WM patients have a CXCR4 mutation, which is associated with treatment resistance and greater disease burden.
Mavorixafor is an antagonist of CXCR4 and X4's lead therapeutic candidate. The firm is conducting the trial in collaboration with the Leukemia & Lymphoma Society.
Within this trial, researchers expect to enroll between a dozen and 18 WM patients, and they will measure how the combination treatment changes patients' serum immunoglobulin M and hemoglobin from baseline, which are biomarkers of clinical response in WM.