## Abstract

Autologous stem cell transplantation (ASCT) remains the standard consolidation therapy for patients with multiple myeloma (MM) and chemosensitive relapsed lymphoma (r-Ly). Peripheral blood as a source of stem cells (PBSC) has largely replaced marrow and has the advantage of improved engraftment rates. PBSC are routinely collected following administration of chemotherapy in combination with GCSF. However, the resultant pancytopenia poses a significant risk to patients and additional chemotherapy prior to ASCT may lead to increased end organ damage potentially precluding future therapies (including ASCT). Novel agents can achieve PBSC mobilisation without the use of cytotoxics. In the advent of such drugs, we reviewed the efficacy of, and complications experienced by patients during PBSC mobilisation. We also analysed the cost implications of adverse events. Of 151 consecutive attempts, 13.2% of patients failed to reach our criteria in order to attempt pheresis (1 × 104 CD34 cells/ml). Of those achieving target and undergoing pheresis, 6% did not achieve an adequate cell dose for future ASCT (2 × 106CD34+cells/kg) giving an overall failure rate of 19.2%. Furthermore 17.9% failed to harvest our ideal of 4 × 106/kg (permitting >1 ASCT procedure). Factors contributing to failure in achieving target CD34+ve PB count on univariate analysis were; >2 lines of previous chemotherapy and occurrence of neutropenic sepsis (NS (p=0.002, and 0.005 respectively). These factors remained significant on multivariate analysis (RR: 4.4 and 6.2). These same factors also affected CD34+ cell yield on both univariate and multivariate analysis (RR: 3.3 and 4.6). No differences were seen between MM and r-Ly. Overall, the complication rate was 34.4%, with 24.1% of patients suffering NS requiring admission. The mortality rate was 1.3% (NS and intra-cranial bleed). Of those developing NS, only 52% eventually harvested sufficient cells, but with a median delay of 3 days. The median cost of PBSC collection was $17,381.46 ($1,978.97–$39,355.73). NS significantly increased the cost of mobilisation at a median cost of$25,532.95 vs \$16,4921) (p=<0.0001).

Conclusion: Our results suggest that patients who are potential candidates for ASCT should be harvested as soon as they achieve remission to prevent failure following additional therapy upon relapse. One fifth of patients will fail. The risks associated with current mobilisation protocols are substantial, and also impact greatly on cost, particularly relevant in the current climate of economic probity. Therefore these data suggests that transplant centres should consider the use of non-myelosuppressive agents either in place of, or as a dose reduction strategy for autologous stem cell procurement.

Disclosures: Gabriel:Genzyme pharmaceuticals: Research Funding.

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