- Plerixafor is given as subcutaneous injection (under the skin). The injection should be given at approximately the same time each day (If participants would like the option to administer their Plerixfor in the evening rather than in the morning on non-clinic days, this is a possibility, provided certain conditions are met). The research doctor will specify which days participants should take plerixafor. In general, plerixafor will be given once daily during the first three weeks of every cycle (during part 3, patients will receive plerixafor the last week of each cycle, as well). For the first week (5-7 days) of Cycle 1, the injections will be given in the clinic and the nurses will teach the participant and their spouse/friend/family member how to administer the injections.