Influence of Stem Cell Mobilization After Cyclophosphamide, Thalidomide and Dexamethasone (CTD) Regimen in Patients with Newly Diagnosed Multiple Myeloma

CTD regimen has been known as an effective induction therapy in patients with newly diagnosed MM. But, there were inconsistent results for the autologous stem cell yield for transplantation. The aim of present study was to identify the influence of CTD therapy on outcome of peripheral blood stem cell (PBSC) collection.

Forty-eight patients received 4 cycles of CTD therapy. Stem cells were mobilized with cyclophosphamide (3.0 g/m²) and G-CSF (10 ƒÝg/kg, daily) or G-CSF alone. Patients failing to collect ≤ 4.0 × 10⁶ CD34⁺ cells /kg received a second mobilization courses.

The median age at diagnosis was 56 years (range, 39–69). Median duration from start of CTD therapy to first collection was 4.6 months (range, 3.3–8.7). Forty-four patients were mobilized with cyclophosphamide following with G-CSF and 4 patients with G-CSF alone. The median day of apheresis was 3 days (range, 2–7). The response rate for CTD regimen at mobilization was 10% (5/48) of CR, 25% (12/48) of VGPR and 63% (30/48) of PR. A median number of harvested CD34⁺ cells was 8.6 × 10⁶ cells/kg. At the first mobilization, 83% (40/48) of patients had been reached the minimal PBSC collection target of ≥ 2.0 × 10⁶ CD34⁺ cells/kg and 71% (34/48) of patients achieved the collection ≥ 4.0 × 10⁶ CD34⁺ cells/kg. At the end of second mobilization, 90%(43/48) of patients had yields of at least ≥ 2.0 × 10⁶ CD34⁺ cells/kg and 77% (37/48) of patients had yields of ≥ 4.0 × 10⁶ CD34⁺ cells/kg. During mobilization period, three patients were developed grade 3/4 non-hematologic adverse events.

CTD regimen is an effective induction therapy in patients with newly diagnosed MM showing high response rate and acceptable rate of autologuos stem cell yield without any detrimental effect for the following stem cell collection.

No relevant conflicts of interest to declare.