PB2365 CELL DOSE AND HEMATOLOGIC RECOVERY AFTER AUTOLOGOUS STEM CELL TRANSPLANTATION FOR MULTIPLE MYELOMA

Abstract

Background:The relation between the dose of the infused hematopoietic stem cells and the time of hematologic recovery after autologous transplantation has been investigated in different types of patients.Aims:We assessed the strength of this relation in patients with multiple myeloma, transplanted in our center.Methods:We analyzed the relation between different factors and the hematologic recovery in 277 transplantations performed on 249 patients (138 male and 111 female) with multiple myeloma, who underwent autologous transplants between 2005 and 2018. Twenty eight of them had second (tandem or not tandem) transplantation.The conditioning regimen consisted of Melphalan for most of the patients. The average age at the time of transplantation was 55 years (35 ‐ 71). Patients were transplanted with an average cell dose of 2,95 × 106/kg (1,30 – 9,20 × 106/kg) for the first transplantation and 2,36 × 106/kg (1,64 – 3,19 × 106/kg) for the second one (every patient received the same cell dose as for the first) with average cell viability 95,34 % (70 – 99%), with little difference between first and second transplantation.Results:The average time for hematological recovery was 11,60 (between 9 and 19) days for the neutrophils, and 12.11 (between 9 and 20) days for the platelets.We found no correlation between the cell dose and the hematological recovery. There was no difference in the hematopoietic recovery between the first and the second transplantation in the patients, who underwent tandem or two transplantations.Summary/Conclusion:Recovery time is considered by some to be a function of the effective stem cell number. We did not find such correlation, probably because in the analyzed group all the patients, except four of them, received a dose greater than 2 × 106/kg cell, which is accepted as a safe dose for autologous stem cell transplantation.