Combination treatment with SCH 546738 and IFN-β had a significant additive effect in delaying disease onset and attenuating disease severity compared to treatment with either SCH 546738 or IFN-β alone (Figure 7) suggesting that a CXCR3 antagonist may offer substantial 'add-on' efficacy onto existing IFN-β therapy and further delay the occurrence of relapses in MS patients. Here, CXCR3 is linked to myeloid sarcoma.