Burixafor Demonstrates Rapid Mobilization Advantage in Multiple Myeloma Stem Cell Collection

Exicure Inc.'s (XCUR) stock rallied over 65% to $8.69 in overnight trading following encouraging clinical trial outcomes for Burixafor, an investigational compound designed to mobilize hematopoietic stem cells in multiple myeloma patients. The breakthrough findings were presented at the ASH Annual Meeting, where researchers detailed how the drug’s unique mechanism enables same-day treatment and cell collection procedures.

Understanding Burixafor’s Clinical Mechanism

Burixafor operates by inhibiting CXCL12 binding to CXCR4 receptors on hematopoietic progenitor cells, effectively mobilizing these cells from bone marrow reserves into the circulatory system. When used in combination with propranolol and granulocyte colony-stimulating factor, the investigational small molecule facilitates the rapid movement of CD34+ stem cells into peripheral blood, where they can be harvested via leukapheresis for transplantation purposes. This approach addresses a critical need in treating multiple myeloma, a rare hematologic malignancy affecting plasma cells in bone marrow that disrupts normal blood production, compromises immune function, and frequently leads to bone deterioration and renal complications.

Trial Results: Remarkable Collection Efficiency

The phase 2 study evaluated whether Burixafor could optimize CD34+ cell collection for patients requiring autologous hematopoietic cell transplantation (AHCT), the established standard of care following high-dose chemotherapy in newly diagnosed multiple myeloma. Among 19 study participants, 17 individuals (89.5%) successfully collected the required minimum threshold of 2 × 10^6 CD34+ cells per kilogram of body weight during their initial two leukapheresis sessions, while only 2 participants required a third collection session to achieve adequate cell counts.

Post-transplant engraftment data proved equally compelling: patients demonstrated median neutrophil recovery in 13 days and platelet reconstitution in 17.5 days, indicating robust hematopoietic recovery.

Speed Advantage Over Existing Therapies

What distinguishes Burixafor from currently FDA-approved CXCR4 antagonists such as plerixafor and motixafortide is its mobilization kinetics. The drug achieves peak CD34+ peripheral levels within one hour of administration, making simultaneous Burixafor dosing and leukapheresis feasible in a single-day protocol. In contrast, existing CXCR4 inhibitors typically require overnight pretreatment before apheresis procedures can commence.

XCUR closed Monday’s trading session at $5.33, reflecting a 3.50% gain prior to the trial announcement. The data positions Burixafor as a potential advance in streamlining stem cell mobilization procedures for multiple myeloma patients undergoing transplantation.