A drug which failed to reach the market as a treatment for HIV/AIDS has recently been shown to improve the survival of mice infected with West Nile virus, a virus that can cause encephalitis. It is believed that the drug, AMD-3100, acts by allowing T-cells to cross the blood-brain barrier and combat virus infecting the brain.
The drug works by blocking the receptor for the chemokine, CXCR4, and was originally developed to prevent the syncytium-forming variant of HIV using this receptor to gain entry to cells. Clinical trials, however, failed to show robust anti-viral activity.
The CXCR4 receptor and its physiological ligand, SDF-1, are also involved in mobilisation of hematopoietic stem cells into the bloodstream. Genzyme has recently filed applications in the US and Europe for AMD-3100 (Mozobil™, plerixafor) to enhance mobilization of hematopoietic stem cells for collection and subsequent autologous transplantation in patients with lymphoma and multiple myeloma. Because patients receive high-dose chemotherapy, which destroys bone marrow, a stem cell transplant is needed after chemotherapy to replenish blood-forming bone marrow cells. Genzyme has been developing Mozobil since its acquisition of AnorMED in 2006.