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Exicure, Inc. (Nasdaq: XCUR), a clinical-stage biotechnology company developing therapeutics for hematologic diseases, today announced positive results from its completed Phase 2 trial evaluating burixafor (GPC-100) in combination with propranolol and granulocyte colony-stimulating factor (G-CSF) for the mobilization of hematopoietic progenitor cells (HPCs) in patients with multiple myeloma undergoing autologous hematopoietic cell transplantation (AHCT). The data, which showed that approximately 90% of study participants achieved the primary endpoint, were presented today in an oral session at the 67th American Society of Hematology (ASH) Annual Meeting in Orlando, Florida.
Burixafor is an investigational small molecule that blocks CXCL12 binding to CXCR4 receptors on HPCs, rapidly mobilizing these cells from the bone marrow into the peripheral blood. In preclinical studies, propranolol enhanced burixafor-induced mobilization by inhibiting the β2-adrenergic receptor (β2AR).
In the open-label, multicenter Phase 2 trial (NCT05561751), 17 of 19 participants (89.5%) achieved the primary endpoint of collecting ≥2 × 10⁶ CD34+ cells/kg within two leukapheresis sessions. Two required another session to achieve 2x10 6 CD34+ cells/kg. Among participants who proceeded to transplant, the median time to neutrophil engraftment was 13 days, and the median time to platelet engraftment was 17.5 days. Burixafor has a differentiated and rapid mobilization kinetics, with peak peripheral levels of CD34+ cells observed within one hour of administration. This distinguishes it from other CXCR4 inhibitors and allows for same day burixafor administration and apheresis.
Notably, 16 of 19 participants (84.2%) had prior exposure to daratumumab, a therapy associated with reduced mobilization, yet 14 of those 16 participants (87.5%) achieved the primary endpoint, including 12 of 14 participants (85.7%) who had received both daratumumab and lenalidomide. Longer intervals between the last dose of daratumumab and leukapheresis were associated with higher CD34+ cell yields.
Burixafor administered in combination with propranolol and G-CSF was well tolerated and demonstrated an excellent safety profile. There were no burixafor-related adverse events higher than Grade 2.
"In this Phase 2 study, the combination of burixafor, G-CSF and propranolol showed an excellent safety profile and supported reliable mobilization of hematopoietic progenitor cells, allowing all participants who elected to proceed with transplant to undergo AHCT and successfully engraft," said Jack Khouri, M.D., Associate Professor of Medicine at the Cleveland Clinic Lerner College of Medicine, Case Western Reserve University and the study's lead investigator. "We're encouraged by these results, particularly given the high proportion of participants previously treated with daratumumab, an agent which may reduce stem cell yield. The ability to achieve peak circulating HPC levels rapidly after burixafor administration for immediate leukapheresis also has the potential to meaningfully improve the patient experience by reducing the burden of the mobilization process."
Oral Presentation Details
Abstract Number: 1050
Title: An open-label, multi-center Phase 2 study to assess the safety and efficacy of burixafor (GPC-100) and propranolol with G-CSF for the mobilization of hematopoietic progenitor cells in patients with multiple myeloma
Presenter: Dr. Jack Khouri, Associate Professor of Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University
Session: 711. Cell Collection and Manufacturing of HSPCs, CAR-T Cells, and Other Cellular Therapy Products: Refining CAR-T Cells and Engineered HSPCs; New Approaches to HSPC mobilization
Date and Time: December 8, 2025, 5:45-6:00pm EST
Location: Hyatt - Regency Ballroom R
About Burixafor (GPC-100)
Burixafor (GPC-100) is a highly selective small molecule antagonist of CXCR4, a chemokine receptor that plays a central role in retaining hematopoietic stem cells in the bone marrow niche. By blocking CXCR4, burixafor may enhance the mobilization of these cells into the peripheral blood for collection and use in autologous stem cell transplant (ASCT) procedures. Originally developed by GPCR Therapeutics, Inc., burixafor became part of Exicure's pipeline following the company's acquisition in January 2025. In addition to multiple myeloma, burixafor is also being considered in other diseases where improved stem cell mobilization could help enable more efficient and effective treatment approaches, such as sickle cell disease, rare diseases requiring autologous transplant, and cell and gene therapy settings. A chemosensitization trial in AML is also being planned, leveraging burixafor's mechanism of mobilizing malignant cells from protective bone marrow niches into the peripheral blood, where they may be more effectively targeted by chemotherapy.
About Exicure
Exicure, Inc. (Nasdaq: XCUR) is a clinical-stage biotechnology company developing therapies to address key challenges in hematologic diseases. The company's lead program, burixafor (GPC-100), is being evaluated for its ability to improve stem cell mobilization in multiple myeloma, sickle cell disease, and in support of cell and gene therapy. It is also being studied as a potential chemosensitizing agent in acute myeloid leukemia (AML). For more information, visit www.exicuretx.com .
Media Contact:
Sarah Ellinwood, PhD
Kendall Investor Relations
sellinwood@kendallir.com
