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Heart & blood

Motixafortide

EvidenceFDA approved

ClassCXCR4 antagonist peptide

Motixafortide is an FDA-approved CXCR4-blocking peptide that moves stem cells into the blood for collection in multiple myeloma. Learn how it works.

Reviewed by: William Maish, MD MBA MPH, Clinical Product Lead
Published: October 5, 2026
Last updated: October 5, 2026

Key takeaway

Motixafortide (sold as Aphexda) is a peptide that blocks the CXCR4 receptor to pull stem cells out of the bone marrow into the blood, where they can be collected for a transplant in people with multiple myeloma. Used with a standard mobilizing drug, it raises the yield of stem cells collected. It has been FDA-approved in the U.S. since 2023 and is given as a subcutaneous injection.

At a glance

What it is	A CXCR4 receptor antagonist peptide
Approved for	Mobilizing stem cells for collection and autologous transplant in multiple myeloma, in combination with filgrastim
Key fact	In the GENESIS trial, far more patients collected the target stem-cell dose in up to two sessions with motixafortide plus filgrastim than with filgrastim alone
Route	Subcutaneous injection
Evidence strength	FDA approved

What is motixafortide?

Motixafortide, sold under the brand Aphexda, is a synthetic cyclic peptide that blocks the CXCR4 receptor. It is used in stem-cell transplantation for multiple myeloma, specifically to help collect enough of a patient's own blood-forming stem cells before a transplant. It was developed under the codes BL-8040 and BKT140 and approved in the United States in 2023.

How does motixafortide work?

Blood-forming stem cells are normally held in the bone marrow by the interaction between the CXCR4 receptor on the stem cells and a marrow signal called CXCL12 (also known as SDF-1). Motixafortide is a high-affinity, long-acting CXCR4 antagonist that interrupts this anchoring signal, releasing stem cells from the marrow into the bloodstream, where they can be collected by apheresis.

It is used together with filgrastim, a growth factor that also mobilizes stem cells, and the two work synergistically to raise the yield. Collecting enough stem cells in as few sessions as possible matters for the success and efficiency of an autologous transplant. In the phase 3 GENESIS trial, far more patients reached the target collection of CD34-positive cells in up to two apheresis sessions with motixafortide plus filgrastim than with filgrastim alone¹.

Is it FDA-approved?

Yes. Motixafortide was approved² by the FDA in 2023 for use in combination with filgrastim to mobilize stem cells for collection and subsequent autologous transplantation in patients with multiple myeloma. It is given as a subcutaneous injection, with premedication to reduce the risk of reactions.

What is motixafortide prescribed for?

Motixafortide is prescribed, alongside filgrastim, to mobilize blood-forming stem cells into the circulation so they can be collected for an autologous (self) stem-cell transplant in people with multiple myeloma. Patients receive an antihistamine and other premedication before dosing.

What are the side effects?

According to the prescribing information², common side effects include:

Injection-site reactions such as pain, redness, and itching
Flushing
Back pain and nausea

More serious considerations include:

Serious hypersensitivity or systemic reactions, so premedication and monitoring are used
The potential to mobilize tumor cells, which is why it is not used in leukemia
Embryo-fetal toxicity

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Sources: FDA prescribing information for Aphexda; the GENESIS trial (Crees et al., Nature Medicine, 2023, DOI: 10.1038/s41591-023-02273-z¹), indexed on PubMed. This document is educational and does not constitute medical advice.