Prospective Comparative Study of Etoposide plus G-CSF versus G-CSF Alone, Followed by Risk-Adapted Plerixafor for Peripheral Blood Stem Cell Mobilization in Patients with Newly Diagnosed Multiple Myeloma: CAtholic REsearch Network for Multiple Myeloma Study (CAREMM-2001).

To explore the optimal mobilization for multiple myeloma (MM) patients, we conducted a prospective trial comparing single-dose etoposide (375 mg/m 2 for one day) plus G-CSF versus G-CSF alone, followed by risk-adapted plerixafor. After randomization, 27 patients in the etoposide group and 29 patients in the G-CSF alone group received mobilizations. Six (22.2%) patients in the etoposide group and 15 (51.7%) patients in the G-CSF alone group received plerixafor based on a peripheral blood CD34+ cell count of < 15/mm 3 ( p = 0.045). The median count of CD34+ cells collected was significantly higher in the etoposide group (9.5 × 10 6 /kg vs. 7.9 × 10 6 /kg; p = 0.018), but the optimal collection rate (CD34+ cells ≥ 6 × 10 6 /kg) was not significantly different between the two groups (96.3% vs. 82.8%; p = 0.195). The rate of CD34+ cells collected of ≥ 8.0 × 10 6 /kg was significantly higher in the etoposide group (77.8% vs. 44.8%; p = 0.025). Although the rates of grade II-IV thrombocytopenia (63.0% vs. 31.0%; p = 0.031) and grade I-IV nausea (14.8% vs. 0%; p = 0.048) were significantly higher in the etoposide group, the rates of adverse events were low in both groups, with no neutropenic fever or septic shock. Thus, both single-dose etoposide plus G-CSF and G-CSF alone with risk-adapted plerixafor were effective and safe, but the former may be the better option for patients who are expected to receive two or more transplantations.