Comparison of autologous peripheral blood stem cell dosing by ideal vs actual body weight

In this retrospective study, we evaluated the predictability of PBSC dose f or hematopoietic engraftment comparing that calculated by ideal body weight (IBW) vs another calculated by actual body weight (ABW) for each patient. Sixty-three consecutive patients treated similarly using one transplant pro tocol were analyzed. While all patients had data available on CFU-CM and nu cleated cells (NC), data on CD34(+) enumeration was present only in 34 pati ents. We found that 49% of the patients were greater than 25% over their IB W. In addition, least-squares linear regression was used to assess the stre ngth of the linear relationship between the inverse of cell dose/kg of ABW or IBW and time to AGC or platelet engraftment and showed no difference in r(2) values for platelet engraftment, while using dose/kg of IBW greatly im proved the ability of NC (r(2) improved from 0.19 for ABW to 0.35 for IBW) and CFU-GM (r(2) improved from 0.35 for ABW to 0.53 for IBW) to predict tim e to AGC engraftment, but did not change the CD34 r(2). Hazard ratios were estimated using Cox proportional hazards regression and in all instances we re found greater than 1.0 indicating that the probability of engraftment in creased as cell dose/kg ABW or IBW increased, Finally, our data showed that 10 patients (16%) could have had one less apheresis procedure performed to obtain their set target stem cell dose calculated per kg IBW rather than A BW, In conclusion, PBSC dose per kg IBW is as good or better predictor of e ngraftment of AGC and may lead to cost savings in a certain subset of patie nts.