Impact of quadruplet induction therapy on stem cell mobilization yields in newly diagnosed multiple myeloma

Daratumumab-containing quadruplet induction regimens have recently become the standard of care for patients with newly diagnosed multiple myeloma who are candidates for autologous hematopoietic stem cell transplantation. Daratumumab is a known immunosuppressant, and previous studies have shown that it may impair stem cell mobilization yields. We report a retrospective study of 104 newly diagnosed multiple myeloma patients comparing mobilization yields between those who received quadruplet daratumumab-containing induction and those who received traditional three-drug induction. Our results demonstrated that there were no statistically significant differences in achieving the patient-specific minimally required CD34+ cell yield after the first mobilization attempt between patients in the daratumumab-containing arm and those in the non-daratumumab-containing arm (P = 0.28).However, patients who received the quadruplet induction regimen with daratumumab experienced a statistically significant longer duration of apheresis collection (median of 2 days in the daratumumab-containing arm vs. 1 day in the non-daratumumab-containing arm, P = 0.011) than those who received traditional three-drug induction.Our findings reinforce the importance of incorporating both granulocyte-colony stimulating factors and plerixafor upfront into mobilization practices. Furthermore, the findings of this study may have implications for the judicious use of apheresis machines and further inform the optimal delivery of daratumumab-containing induction therapies for newly diagnosed multiple myeloma.