Exicure’s open-label, multicenter Phase 2 trial in multiple myeloma reported that 89.7% of patients met the study’s primary mobilization endpoint on a regimen of burixafor plus propranolol and G-CSF, with same-day administration and leukapheresis and a favorable safety profile in previously disclosed topline results.
The company will deliver an encore poster of the dataset at the ASTCT/CIBMTR Tandem Meetings on February 5. The study evaluates burixafor, a small-molecule CXCR4 antagonist, as part of a three-drug approach to mobilize hematopoietic progenitor cells ahead of autologous transplantation. The poster comes as Exicure consolidates around a hematology-focused strategy built on assets acquired with GPCR Therapeutics in early 2025, with parallel development lines in multiple myeloma, sickle cell disease, cell and gene therapy support, and a planned AML chemosensitization study leveraging CXCR4 blockade to dislodge malignant cells from marrow niches.
The positioning is explicit: Exicure is aiming to differentiate in a mobilization market reshaped by modern induction regimens that blunt collection yields and by the emergence of CXCR4-directed competitors. Plerixafor remains widely used as an add-on to G-CSF, while motixafortide’s approval added a potent option geared toward single-session collections. Burixafor’s bet is twofold. First, it leans into operational simplicity by claiming predictable mobilization that allows same-day apheresis, a scheduling lever that matters to sites under capacity strain. Second, it layers propranolol onto CXCR4 inhibition, a mechanistic twist that, if reproducible across centers, could carve out a niche in poor mobilizers without adding significant toxicity or monitoring burden.
For sites, a regimen that reliably enables one-day mobilization and collection could reduce apheresis chair time, compress G-CSF dosing windows, and minimize rescue mobilization logistics. That directly impacts throughput and staffing flexibility, especially in centers where lenalidomide- and daratumumab-exposed patients drive higher failure rates. For sponsors and CROs, the operational read-through is a Phase 3 design problem: single-arm signals must translate into a comparator-based trial that captures the right endpoints—CD34+ yield, proportion collecting in one session, need for rescue agents, and failure rates—against either plerixafor or a more recent standard. Regulators will also expect clarity on the role of propranolol within the label strategy and on subgroup performance within contemporary induction backbones.
Cost and access dynamics will matter as much as efficacy. If same-day mobilization consistently trims apheresis sessions and ancillary resource use, payers may weigh those offsets against drug acquisition costs in a market that now has multiple CXCR4 options. For sickle cell disease, where G-CSF is often avoided due to safety concerns, Exicure’s broader development plan will need to demonstrate that burixafor-based regimens can mobilize effectively without G-CSF, a different risk-benefit calculus than in myeloma. The AML chemosensitization concept is strategically adjacent rather than overlapping, but positive signals there could strengthen the CXCR4 franchise narrative and de-risk manufacturing and supply planning across indications.
What to watch next is straightforward. The ASTCT poster should specify the primary endpoint definition, one-session collection rates, rescue usage, and adverse event granularity, particularly cardiovascular signals given concomitant propranolol. The pivotal path will hinge on comparator selection, statistical strategy, and the feasibility of a same-day workflow across diverse transplant programs. Any update on SCD trial design will be a litmus test for the platform’s breadth. Ultimately, adoption will turn on whether Exicure can prove repeatable, center-agnostic operational gains that translate into fewer collection days and lower failure rates, not just incremental mobilization biology.
