Efficacy and safety of hematopoietic stem cell remobilization with plerixafor+G-CSF in adult patients with germ cell tumors.

Autologous hematopoietic SCT (auto-HSCT) can be curative for patients with germ cell tumors. Poor stem cell mobilization jeopardizes the ability to deliver this therapy. Herein, we describe a retrospective study examining safety and efficacy of plerixafor in combination with G-CSF for patients with germ cell tumors who had previously failed stem cell collection. Overall, 21 patients with germ cell tumors and previous mobilization failure were remobilized with G-CSF (10 μg/kg SC) and plerixafor (0.24 mg/kg SC) beginning the evening of day 4 of G-CSF treatment. Dosing of G-CSF and plerixafor was repeated until collection of ≥ 2 × 10(6) CD34+ cells/kg. Remobilization resulted in a median yield of 3.2 × 10(6) CD34+ cells/kg. A total of 17 (81%) patients collected ≥ 2 × 10(6) and 9 (43%) patients collected ≥ 4 × 10(6) CD34+ cells/kg in a median of 2 (range 1-3) and 3 (range 1-4) days, respectively. In all, 16 (76%) patients proceeded to transplant; 8 (38%) received tandem transplants. There were no serious adverse events. In summary, the majority of patients with germ cell tumors who failed prior mobilization with growth factors ± chemotherapy were remobilized with plerixafor plus G-CSF facilitating at least one auto-HSCT. Use of plerixafor plus G-CSF can increase access of this potentially life-saving procedure to patients with high-risk germ cell tumors.