Abstract
Introduction:
Intensive chemotherapy followed by autologous stem cell transplantation (ASCT) is currently the treatment of choice in multiple myeloma (MM). Mobilization of hematopoietic stem cell blood (HSCs) can be achieved either by the combination of chemotherapy plus growth factors or by growth factors alone. However, there is no consensus concerning the dose of growth factor alone that should be administered, with ranges varying from 5 microgr to 16 microgr/kg body weight.
In this context, we report our experience in mobilization of HSCs using growth factor alone at the dose between 15 microgr /kg and 10 microgr /kg in MM.
Patients and methods:
A total of 340 ASCT were performed in our center, from May 2009 until June the 31st 2016. These concerned 221 patients with MM. Patients were hospitalized at day -5 on which mobilization started with G-CSF alone (filgrastim) at the dose of 15 microgr /kg/daily subcutaneously for 5 days from May 2009 to October 2012 and at the dose of 10 microgr /kg from November 2012 to June 2016. The white blood cell count was assessed daily. Apheresis was performed at day -2 and day -1 using a Spectra Optia CMN device, and the CD34+ count was assessed by flow cytometry. A single leukapheresis was performed if the number of CD34+ cells was above 2.106/kg. Failure of mobilization was defined as a level of CD34+ less than 2.106/kg, after two leukapheresis.
In our study patients were divided into two groups: Group1 (G-CSF=15 microgr /kg) and Group 2 (G-CSF=10 microgr /kg) and the number of CD34+ were divided into three groups: optimal (³5.0 x 106 CD34+ cells/kg), suboptimal (2.0Ð5.0 x 106 CD34+ cells/kg) and poor (<2.0 x 106 CD34+ cells/kg) mobilization. Intensification was done using melphalan 200 mg/m2 on day -1.
Results:
Patient's characteristics are shown in Table 1. No significant difference was observed between the 2 groups. In this study, we found no significant difference in terms of optimal (p= 0.73), sub-optimal (p= 0.19) or poor (p= 0.11) harvest of stem cells between the 2 groups (table 2). Among the poor mobilizators with G-CSF, only 4 of them had a level of CD34+ harvest less than 0.5 x 106/kg. These patients did not receive an ASCT. 1,3% (4) of all apheresis failed to achieve acceptable harvest level.
Conclusion:
Our study showed that the mobilization regimen with G-CSF alone at the doses of 10 microgr/kg have the same efficacy as the doses of 15 microgr/kg and is interesting alternative to chemotherapy and G-CSF in patients with MM because it can be administered as an outpatient and is not associated with the risk of febrile neutropenia.
No relevant conflicts of interest to declare.
