Summary:The number of CD34+ cells infused influences the speed of hematologic recovery post-transplant. There are limited data on whether ideal (IBW) or actual (ABW) body weight should be used to calculate CD34+ cell dose. We compared the correlation between recovery to 0.5 Â 10 9 /l neutrophils and the CD34+ cell dose based upon ABW as well as IBW in 87 patients autografted for cancer. ABW was X25% over IBW in 43% of patients. The median number of CD34+ cells administered was 3.6 Â 10 6 /kg ABW and 4.2 Â 10 6 /kg IBW. The time to neutrophil recovery was 8-15 days (median 10). There was a stronger inverse correlation between CD34+ cell dose/IBW and neutrophil recovery (r 2 ¼ 0.308; Po0.0001) than between CD34+ cell dose/ABW and neutrophil recovery (r 2 ¼ 0.267; Po0.0001). The median time to neutrophil recovery was comparable for those receiving X2 Â 10 6 /kg CD34+ cells/kg IBW as well as ABW (10 days) and those receiving X2 Â 10 6 /kg CD34+ cells/kg IBW but o2/kg ABW (10 days), but was significantly slower for those receiving o2 Â 10 6 /kg CD34+ cells/kg IBW (12 days). These data show that the CD34+ cell dose based on IBW is a better predictor of neutrophil recovery after autotransplantation.

Summary:The time to myeloid recovery after autologous hematopoietic stem cell transplantation (HSCT) is usually defined as the first of 3 consecutive days with an absolute neutrophil count (ANC) of у0.5 ؋ 10 9 /l (ANC500). Universal documentation of ANC500 for 3 consecutive days, historically required to ensure robust myeloid recovery, has become difficult with a trend towards early discharge and outpatient HSCT. We studied 90 autografted patients to see how frequently ANC declined after having reached у0.5 ؋ 10 9 /l. ANC500 was documented on 2 and 3 consecutive days in 14 and 63 patients, respectively. ANC increased by a median of 213% from the 1st to the 2nd day (rise in 75 and unchanged in two), and by a median of 142% from the 2nd day to the 3rd (rise in 60, unchanged in one, and decline in two; higher than the 1st day in the latter three). The increase from the 1st to the 3rd day was 13-3433% (median, 557%). Thus, in all 63 patients, no decline below ANC500 was seen, and the first day with ANC500 was also the first of 3 consecutive days with ANC500. The remaining 13 patients had repeat counts 2-7 days after the 1st day with ANC500 documenting further increase in ANC with no evidence of failed engraftment. These data show that the first day with ANC500 is also consistently the first of 3 consecutive days with ANC500 in autografted patients. Therefore, the traditional definition of myeloid engraftment should be changed to consider the first day with ANC500 as the day of engraftment without necessarily documenting ANC500 on the subsequent 1-2 days. This simple change in definition has significant implications for how data are reported to transplant registries and how peerreview organizations such as the Foundation for the Accreditation of Hematopoietic Cell Therapy (FAHCT) define completeness of data.

CD34 þ cell dose calculations are usually based on actual body weight (ABW). We have shown that ideal body weight (IBW) may provide a better basis for this in a small population of patients with hematologic malignancies. This was studied further in 514 myeloma autografts. The CD34 þ cell doses (10 /l platelets 0.85 versus 0.84. CD34 þ cell doses based on IBW as well as ABW significantly affected engraftment when analyzed separately as continuous variables. However, when analyzed together, only the dose based on IBW retained significance. We conclude that calculation of CD34 þ cell numbers for autotransplantation should be based on IBW.

Summary:The number of CD34 þ cells infused influences hematologic recovery after transplantation. Limited data suggest that cell dose should be based on ideal (IBW) rather than actual (ABW) body weight for autotransplantation, but none in allografts. We compared the correlation between recovery to 0.5 Â 10 9 /l neutrophils and the CD34 þ cell dose based upon ABW and IBW in 78 allograft recipients. ABW was X25% over IBW in 47% of patients. The median CD34 þ cell dose was 5.1 Â 10 6 /kg IBW and 4.4 Â 10 6 /kg ABW. The time to neutrophil recovery was 8-26 days (median 12). There was a stronger inverse correlation between CD34 þ cell dose/IBW and neutrophil recovery (r 2 ¼ 0.160; Po0.0001) than between CD34 þ cell dose/ABW and neutrophil recovery (r 2 ¼ 0.138; P ¼ 0.001). When neutrophil recovery in patients receiving o3 or o5 Â 10 6 CD34 þ cells/kg was compared to those receiving X3 or X5 Â 10 6 CD34 þ cells/kg, respectively, separately by IBW and ABW, the magnitude and significance of the differences were greater for IBW-based comparisons. These data suggest the CD34 þ cell dose based on IBW is a better predictor of neutrophil recovery after allografting. Further work in a larger, more homogeneous group of patients is required to confirm this observation.

After a hospital-wide formulary change resulted in the replacement of filgrastim with TBO-filgrastim for all on- and off-label indications, we performed a retrospective comparison of patients with myeloma receiving 200 mg/m(2) melphalan with autologous hematopoietic stem cell transplantation to see whether the type of growth factor used post-transplant made a difference. One hundred and eighty-two consecutive patients with myeloma were studied, 91 receiving filgrastim immediately prior to the change and 91 receiving TBO-filgrastim afterward. The CD34(+) cell dose was comparable, as were other characteristics. Although the overall time to neutrophil recovery was similar for both groups, early engraftment (≤ 12 d) occurred more often (p = 0.05), and late engraftment (≥ 14 d) less often (p = 0.09) in filgrastim-treated patients. The number of documented infections was significantly less in the TBO-filgrastim group. Day 100 mortality and hospital stay were similar for the two groups. These data indicate that there is no material difference between filgrastim and TBO-filgrastim in this clinical setting.