Dose capping of plerixafor in patients weighing more than 100 kg at one vial led to successful mobilization outcomes and significant cost savings.

BACKGROUND: Plerixafor is frequently used as an adjunct agent to improve mobilization of peripheral blood stem cells in many clinical settings. However, its high cost (>$8000 per single-use 24-mg vial) is a significant concern. The manufacturer-recommended dose is 0.24 mg/kg. Therefore, patients weighing more than 100 kg would require a second vial, thus doubling the drug cost per dose. We implemented a policy of capping the dose of plerixafor at 24 mg, or one vial, for patients weighing more than 100 kg. This retrospective study compares the mobilization of patients more than 100 kg who received capped doses, with historical control patients who received full, uncapped doses.

STUDY DESIGN AND METHODS: Consecutive, eligible patients weighing more than 100 kg who received capped (n = 47) and full doses of plerixafor (n = 40) were identified. Plerixafor was given up-front, as a rescue agent due to suboptimal mobilization, or during remobilization. Baseline characteristics and mobilization data were collected and compared.

RESULTS: Patients in the two groups showed comparable baseline characteristics. They collected similar total numbers of CD34+ cells/kg (median, 4.08 × 106 vs. 3.36 × 106 CD34+ cells/kg; p = 0.86) and achieved comparable collection success rates as defined by collecting more than 2.0 × 106 CD34+ cells/kg (98% vs. 90%, p = 0.21). However, patients who received capped doses required only half of the number of vials of plerixafor (median, 3 vials vs. 6 vials; p < 0.0001).

CONCLUSION: Dose capping plerixafor at 24 mg for patients more than 100 kg is a cost-effective strategy, which achieved comparable mobilization outcomes and reduced the total number of vials of plerixafor used by half.