(HealthDay News) – The addition of plerixafor to standard chemotherapy is feasible in acute myeloid leukemia (AML), resulting in reasonable rates of remission, according to the results of a Phase 1/2 study published online February 2 in Blood.

To investigate whether inhibition of the chemokine receptor and associated ligand axis by plerixafor would increase the sensitivity of AML blasts to chemotherapy, Geoffrey L. Uy, MD, and colleagues from the Washington University School of Medicine in St. Louis, treated 52 patients with relapsed or refractory AML with plerixafor in combination with mitoxantrone, etoposide, and cytarabine.

In the Phase 1 study, the researchers escalated plerixafor to a maximum dosage of 0.24mg/kg/day without dose-limiting toxicities. In the Phase 2 study, 46 patients were treated with plerixafor at the same dosage, in combination with chemotherapy. An overall complete remission rate of 46% was achieved. There was a two-fold mobilization of leukemic blasts into the peripheral circulation. The addition of plerixafor was not associated with symptomatic hyperleukocytosis or delayed count recovery.

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“This is one of the first clinical examples of targeting the environment that leukemia cells live in,” a coauthor of the study said in a statement. “In the future, we may find other drugs, or combinations of drugs, that work better. There are now a number of groups around the world putting together similar approaches.”

Several authors disclosed financial ties, including employment, to Genzyme Oncology/Sanofi. The study was partially funded by Genzyme, which manufactures plerixafor.

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