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    Treatment of Newly Diagnosed Myeloma (excluding t-cell redirection therapy)

    Category: Treatment of Newly Diagnosed Myeloma (excluding t-cell redirection therapy)

    Cytarabine plus G-CSF as second attempt in very poor mobilizer myeloma patients after Cyclophosphamide plus G-CSF and Plerixafor: efficacy of Peripheral Blood Stem Cell (PBSC) Collection

    (PA-410) Cytarabine Plus G-CSF as Second Attempt in Very Poor Mobilizer Myeloma Patients After Cyclophosphamide Plus G-CSF and Plerixafor: Efficacy of Peripheral Blood Stem Cell (PBSC) Collection

    Friday, September 19, 2025

    • GIUSEPPE MELE

      doctor
      Haematology and Stem Cell Transplant Unit, Presidio Ospedaliero A. Perrino, Brindisi (BR), Italy


    Introduction:      Daratumumab plus bortezomib, thalidomide and dexamethasone (D-VTd) strategy represents the current standard of care in transplant-eligible patients with newly diagnosed multiple myeloma (NDTEMM). Data from the trials, metanalysis and real-world experiences showed that, using conventional strategy with cyclophosphamide (CTX) combined with granulocyte colony-stimulating factor (G-CSF) and plerixafor, the median number of CD34+ collected was significantly lower in patients receiving D-VTd. We evaluated the efficacy and safety of cytarabine (Ara-C) plus G-CSF in the subgroup of poor mobilizer myeloma patients following historical mobilization strategy with CTX plus G-CSF and plerixafor.

    Methods:   This observational, retrospective study was conducted across 5 Italian centers. 19 patients affected by NDTEMM and treated with D-VTd induction regimen (8 F and 11 M - mean age 57.5 years [range 43–68]) were included in this analy­sis. The number of induction cycles was 4. One 57-year-old man patient with IgGλ MM, ISS stage I, had previously undergone chemotherapy using the R-CHOP scheme (rituximab, cyclophosphamide, epirubicin, vincristine and prednisone) due to asynchronous non-Hodgkin's lymphoma. All patients were treated with intermediate-dose CTX (2-4 g/m2) plus G-CSF (non-pegylated G-CSF only) at the dose of 5 µg/kg/day in the morning from d5 by subcutaneous injection. On day 12, prior to stem cell collection, only if peripheral CD34+ count was ≤20 μL, patients received 10 µg/kg/day G-CSF via two consecutive subcutaneous injections plus plerixafor (0.24 mg/kg/day) as a subcutaneous injection, without benefit. After the declaration of mobilization failure (CD34+ cell count < 20 μL), all poor mobilizer patients received a second chemo-based strategy to harvest stem cells. The chemotherapy consisted of ARA-C (800 mg/m2 d1 and d2 or 1.600 mg/m2 d1, according to the medi­cal decisions) plus G-CSF 5 µg/kg/day in the morning from d5 until the day of apheresis.

    Results:   All patients achieved adequate CD34+ cell collection without plerixafor. The median of CD34+ cells har­vested was 7.6x106/kg (range 4.3-11.3), with 17/19 (89%) of patients yielding more than 5.0x106/kg. The median number of apheresis was 1 (range 1-2). No red blood cell and platelet transfusions were used. One patient (5%) had febrile neutropenia. 16/19 patients (84%) underwent transplant as planned, receiving a conditioning regimen with high-dose melphalan (200 mg/m2 d2), followed by infusion of autologous PBSC on day 0, and received G-CSF 5 μg/kg from d5 until neutrophil engraftment. The post-transplant course was regular. The time of neutrophil and platelet engraftment was 12 days (range 9-150) and 14 days (range 10-25), respectively. The median length of hospitalization was 21 days (range 17-22).

    Conclusions:   

    Our study showed that the mobilization with Ara-C plus G-CSF, without plerixafor, was highly efficient and safe for patients with MM who were very poor mobilizers after CTX plus G-CSF and plerixafor.