Peripheral Blood CD34+ Percentage at Hematological Recovery after Chemotherapy Is a Good Early Predictor of Harvest: A Single-Center Experience

Abstract

Several algorithms for early prediction of poor-mobilizing patients after chemotherapy and granulocyte colony-stimulating factor administration have been proposed. They generally define peripheral blood cut-off levels of CD34+ cells at a fixed day after starting chemotherapy, mostly with cyclophosphamide. To define an algorithm for early addition of plerixafor regardless of the chemotherapy regimen used, we retrospectively analyzed 280 chemomobilization attempts in 236 patients treated at our institution between 2002 and 2012. In multivariate analysis, CD34+ absolute count and CD34+ percentage upon total leukocyte count at day 1 (defined as the first day in which leukocytes reached a value > 1 × 10(9)/L) were the only factors able to predict a total harvest ≥ 2 × 10(6) CD34+/kg. In patients with day 1 CD34+ lower than 20/μL, the CD34+ percentage was a more reliable predictor of stem cell harvest in the following days than CD34+ absolute count. Upon definition of the best CD34+ cut-off value for identification of poor-mobilizing patients, an algorithm was set up to guide plerixafor administration. It was prospectively validated in 20 patients in 2013 with encouraging results in terms of low incidences of both mobilization failure and plerixafor use. Large prospective trials that define the most cost-effective strategy for just-in-time rescue plerixafor are warranted.

A nationwide survey of the use of plerixafor in patients with lymphoid malignancies who mobilize poorly demonstrates the predominant use of the “on‐demand” scheme of administration at French autologous hematopoietic stem cell transplant programs

“…One potential issue associated with this procedure is the administration of plerixafor in patients who do not necessarily need it; this may especially be of concern in individuals initially mobilized with chemotherapy plus rHuG‐CSF, since this treatment produces a dynamic situation in which circulating PB CD34+ cells increase simultaneously with neutrophil recovery: taking into account only the absolute number of circulating PB CD34+ cells may lead to a premature decision and neglecting the possibility to adequately collect a blood graft by apheresis within 24 to 72 hours, while maintaining the original plan for daily rHuG‐CSF administration. Thus, it is important that experienced professionals evaluate the quality of HSPC mobilization and consider the clinical context and additional biologic variables, including white blood cell and neutrophil counts as well as the percentage of circulating PB CD34+ cells …”

“…Thus, it is important that experienced professionals evaluate the quality of HSPC mobilization and consider the clinical context and additional biologic variables, including white blood cell and neutrophil counts as well as the percentage of circulating PB CD341 cells. 33,39 The reference to an individual ". .…”

UK consensus statement on the use of plerixafor to facilitate autologous peripheral blood stem cell collection to support high‐dose chemoradiotherapy for patients with malignancy

“…Milone et al recommend a trigger peripheral CD34+ count of 20 µl −1 which we believe may be too high; in addition, like Farina et al, the algorithm used is applicable only to one or 2 specific chemomobilization protocols. Sorasio et al suggest a rather complex algorithm which requires peripheral CD34+ count to be performed following chemomobilization at a timepoint when the patient's total white cell count (WCC) is still only 1 × 10 9 /l; this is unlikely to be optimally cost‐effective and is not standard UK practice, given that most patients achieve peak peripheral CD34+ counts after chemomobilization only once total WCC has regenerated to normal levels. The EBMT consensus statement makes recommendations that are not inconsistent with what we have suggested below.…”

“…32 3.5 | Previous published algorithms for pre-emptive plerixafor use during failing PBSC mobilization Several previous algorithms have been published for the preemptive use of plerixafor during failing PBSC mobilization, either during "steady-state" (G-CSF-only) mobilization or during chemomobilization. 18,24,29,[33][34][35] However, in brief, we consider that our suggested algorithm discussed below has the following advantages over almost all previously published algorithms: (a) it is applicable to any mobilization protocol, including many different chemomobilization approaches as well as "steady-state" mobilization; (b) it suggests a pre-apheresis peripheral CD341 threshold of 15 ml 21 as the usual trigger for plerixafor usage, rather than the thresholds of either 10 or 20 ml 21 used in other algorithms, and UK experience (as summarized in Tables 2 and 3) suggests that 15 ml 21 is the optimal threshold; and (3) it is simple.…”

New developments in the use of apheresis to collect haematopoietic cells for cell transplantation and cell therapies

“…Pharmacological modulation of several of the identified interactions that contribute to the maintenance of stem cells in the marrow niches is susceptible to produce a great increase in these numbers. Although biologically inaccurate, circulating stem and progenitor cells are routinely identified as circulating CD34 + cells, because it has proven to be a relevant surrogate marker to predict the content of the collected cell product and from there hematopoietic recovery in the future recipient of transplanted cells. Although other tests have been in existence or introduced to evaluate the hematopoietic potential of collected cell products, none of them proved superior to the detection of CD34 + cells by flow cytometry in terms of rapidity, easiness, clinical relevance or potency assessment.…”