Benefits of Pre-harvest Peripheral Blood CD34 Counts Guided Single Dose Therapy with PLERIXAFOR in Autologous Hematopoietic Stem Cell Transplantation: A Retrospective Study at a Tertiary Care Institute in India.

Peripheral blood is a convenient source of stem cells for hematopoietic stem cell transplantation. However, in autologous transplants, the harvest failure rates are high because of inadequate mobilization using G-CSF alone. Plerixafor is a potent mobilizer when used with G-CSF. However, its routine use is limited by high cost. This is a retrospective study done at a tertiary care oncology centre in India. All the harvest records were analyzed between Jan 2015 and Nov 2017. May 2016 onwards pre-harvest peripheral blood CD34 count was done in all cases of autologous transplants on day 4 of G-CSF therapy and they were given a single dose of Plerixafor if counts were < 20 cell per cumm. The results were compared amongst various groups. A total of 321 cases were analyzed. 172/321 were allogenic transplant cases of which 5% (n = 7) failed to achieve a target live stem cell dose of > 2 million per kg of the recipient. The overall failure rate in autologous group (n = 149) was 27% (n = 41) ( ≤ 0.001 auto vs. allo). The failure rate was higher (36%, n = 28/77) when no intervention with Plerixafor was done. The overall failure rate in the group treated with pre-harvest 34 count based single dose therapy of Plerixafor was 18% (n = 13/72,  = 0.01). However, within this intervention group, the patients who had pre-harvest peripheral blood CD34 above the desired cutoff had a higher failure rate of 21% ( = 0.13). Pre-harvest CD34 count based intervention with Plerixafor help optimizing the cost.