Stimulation of adrenergic activity by desipramine enhances hematopoietic stem and progenitor cell mobilization along with G-CSF in multiple myeloma: A pilot study

Hematopoietic stem cell (HSC) release is positively regulated by the sympathetic nervous system through the β3 adrenergic receptor. Preclinical studies have demonstrated that the combination of desipramine and G-CSF resulted in improved HSC mobilization. Here, we present the results of an open-label single-arm pilot study in patients with multiple myeloma undergoing autologous stem cell transplantation (ASCT) to assess the safety and efficacy of desipramine combined with G-SCF to induce HSC mobilization. The primary endpoint was safety of the combination including engraftment kinetics. The secondary endpoint was the proportion of patients who collected ≥5 × 10⁶ CD34⁺ cells/kg. Outcomes were compared with historical matched controls during the same time period with multiple myeloma mobilized with G-CSF. All study patients received desipramine 100 mg daily for 7 days, starting 4 days prior to G-CSF administration (D-3) and continued taking it along with G-CSF for a total of 7 days. Six of ten patients enrolled completed the protocol with minimal side effects. All of them achieved the target collection of 5 × 10⁶ CD34 cells/kg in a median of 1.5 apheresis session with two patients needing additional plerixafor (16%), while 11 out of 13 patients (85%) achieved the target of 5 × 10⁶ CD34 cells/kg in the historical control group in a median of 2 apheresis procedures and seven patients needed plerixafor (54%). The combination of desipramine and G-CSF is safe and signals improved mobilization over G-CSF alone, providing a possible alternative means of mobilization that needs further investigation.