Third time's a charm? Mobilization of autologous peripheral blood stem cells in patients with two previous failed...

Patients who respond inadequately to plerixafor salvage during autologous peripheral blood stem cell (PBSC) collection are frequently remobilized with plerixafor to collect additional stem cells. However, in patients who fail remobilization, it is unclear whether additional mobilization efforts with plerixafor are useful.

We retrospectively examined the PBSC collections of 15 consecutive patients with lymphoma and multiple myeloma who underwent three mobilizations with plerixafor.

Of the 821 patients who underwent autologous stem cell collections, 15 patients were mobilized three times with plerixafor (1.8%), which enabled 11 (73.3%) patients to reach 2.0 × 10⁶ CD34+ cells/kg or greater. Among patients who eventually collected successfully the median yields from the three collection attempts were 0.46, 0.76, and 1.54 × 10⁶ CD34+ cells/kg, respectively. Among those who collected less than 2.0 × 10⁶ CD34+ cells/kg cumulatively, the median yields were 0.14, 0.33, and 0.22 × 10⁶ CD34+ cells/kg from the three collection attempts. The combined collection yields from the first two mobilization attempts were significantly lower (p = 0.003; range, 0.09-0.73 vs. 0.63-1.84; median, 0.51 vs. 1.36) in those who failed collection.

The majority (73.3%) of patients who underwent three mobilization attempts were eventually able to collect enough cells to permit autologous transplantation. Extremely low peripheral blood CD34+ count after the first dose of plerixafor and collection yields during the first two attempts were associated with a poor collection yield on the third attempt. The risks and benefits of a third mobilization should be weighed to facilitate judicious use of resources.