Abstract 502

Autologous stem cell transplantation with PBSC after high-dose chemotherapy remains standard therapy for patients with symptomatic Multiple Myeloma (MM). Strategies to minimize complications could significantly reduce the morbidity of that procedure. One possibility could be to shorten the duration of induced neutropenia through the injection of an ex-vivo expanded graft. Nineteen patients (pts) received EVEC after high-dose Melphalan (HDM) (200 mg/m2) as the only graft. The ex-vivo expanded procedure has been described elsewhere (Boiron et al. Transfusion 2006 and Ivanovic et al. Transfusion 2006). Briefly, thawed peripheral blood CD 34+ cells collected after G-CSF mobilisation and selected with immunomagnetic devices were incubated for 10 days in a serum free medium (Maco Biotech HP01) with Stem Cell Factor (Amgen), G-CSF (Amgen) and TPO (Amgen: 7 pts; Cellgenix:12 pts). The expanded cells were then thoroughly washed and injected 48h after the HDM injection. The ex-vivo expansion lead to a median fold of 5,4 for CD34+ cells (1,3-11,8); 118 for CD33+ (1-703880); 3386 for CD14+ (4-101075); 28,5 for CD13+ (10-703880) and 13 for CFUs (6-21). The median N° of CD34+ cells injected was 14×10e6/kg (5,3-48). The results of these transplants were compared to those achieved in 38 pts who received unmanipulated PBSC after HDM. Pts and controls were matched for age, sex, stage of the disease, first line chemotherapy ( VAD or VD) status of the disease at time of transplant, year of transplant, time between diagnosis and transplant, CD34+ mobilisation technique (HD cytoxan + G-CSF or G-CSF alone) and the median N° of total nucleated cells and of CD34+ collected. The results are summarized on the table:

EVECPBSCP
19 38  
CD34+ injected cells (x10e6/kg) 14 (5,8-48) 2,6 (1,2-32,5) <0.0001 
Days with < 500 PMN 2 (0-5) 7 (3-17) <0.0001 
Days with <20 000 Plt 0 (0-3) 2,5 (0-12) <0.0001 
Septicemia (N) 11 NS 
Days of febrile neutropenia 1,5 (1-2) 4 (1-16) 0.024 
Hospitalisation (days) 14 (10-22) 19 (15-26) <0.0001 
EVECPBSCP
19 38  
CD34+ injected cells (x10e6/kg) 14 (5,8-48) 2,6 (1,2-32,5) <0.0001 
Days with < 500 PMN 2 (0-5) 7 (3-17) <0.0001 
Days with <20 000 Plt 0 (0-3) 2,5 (0-12) <0.0001 
Septicemia (N) 11 NS 
Days of febrile neutropenia 1,5 (1-2) 4 (1-16) 0.024 
Hospitalisation (days) 14 (10-22) 19 (15-26) <0.0001 

There was no secondary neutropenia in the patients who received EVEC. With a median FU of the entire cohort of 30 m, the median OS for pts who received their first transplant with EVEC and with PBSC is 69 m and not reached respectively (p=NS), the median PFS is 18 m and 27 m (p = NS) and the median time to progression is 14 m and 15 m (p=NS).

Conclusion:

EVEC is feasible, safe and reduce significantly the morbidity of autologous stem cell transplantation after HDM for multiple myeloma.

Disclosures:

Milpied:Amgen France: Honoraria.

Author notes

*

Asterisk with author names denotes non-ASH members.

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