Docetaxel effectively mobilizes peripheral blood CD34+ cells

Feasibility and kinetics of CD34+ hematopoietic progenitor cell mobilization in response to a single administration of docetaxel chemotherapy and pegfilgrastim in a contemporary cohort of patients with metastatic breast cancer

AIM

Autologous hematopoietic stem cell transplantation (auto-HSCT) remains an experimental therapy for metastatic breast cancer (MBC) and there is no established protocol for cluster of differentiation 34⁺ (CD34⁺ ) hematopoietic progenitor cell (HPC) mobilization with historic studies using growth factors with or without chemotherapy. This study describes the feasibility and kinetics of CD34⁺ HPC mobilization following a single administration of docetaxel and the pegylated form of recombinant human granulocyte colony-stimulating factor analogue filgrastim (pegfilgrastim).

METHODS

The study design was serial measurement of peripheral blood CD34⁺ HPC in patients with MBC following a single administration of intravenous (IV) docetaxel 100 mg/m² on day 1 and subcutaneous (SC) pegfilgrastim 6 mg on day 2.

RESULTS

Eight patients with MBC were enrolled. The median age was 56 years (range 51-75 years). All patients had human epidermal growth factor receptor 2 (HER2) negative disease and either hormone refractory or negative disease. Three patients had bone only disease, four had visceral organ disease with or without bone involvement and one had locally unresectable disease only. All patients had prior therapy for early-advanced stage disease and prior therapy for MBC included seven patients receiving at least one line of hormone therapy and three having palliative chemotherapy. Six patients recorded a rise in the CD34⁺ count greater than 20 cells/μL. The median peak level was 40.2 cells/μL (standard deviation = 28.7) occurring on day 9 and with an average duration of 4 days. Overall, treatment was well tolerated with manageable side-effects.

CONCLUSION

The single administration of docetaxel and pegfilgrastim was effective in mobilization of CD34⁺ HPC and peak levels followed a predictable course. This approach needs validation in prospective studies by preparation of auto-HSCT by leukapheresis and quantification of total CD34⁺ HPC yields.

Mobilization of Peripheral Blood Stem Cells Using Regimen Combining Docetaxel with Granulocyte Colony-stimulating Factor in Breast Cancer Patients

OBJECTIVE

To evaluate the effectiveness and safety of the mobilization of peripheral blood hematopoietic stem cells by combining docetaxel with granulocyte colony-stimulating factor (G-CSF) in breast cancer patients.

METHODS

A total of 57 breast cancer patients were treated with docetaxel 120 mg/m(2). When the white blood cell (WBC) count decreased to 1.0×10(9)/L, patients were given G-CSF 5 μg/kg daily by subcutaneous injection until the end of apheresis. Peripheral blood mononuclear cells (MNC) were isolated by Cobe Spectra Apheresis System. The percentage of CD34(+) cell was assayed by flow cytometry.

RESULTS

At a median 6 of days (range 3-8) after the administration of docetaxel, the median WBC count decreased to 1.08×10(9)/L (range 0.20-2.31). The median duration of G-CSF mobilization was 3 days (range 2-7). The MNC collection was conducted 8-12 days (median 10 days) after docetaxel treatment. The median MNC was 5.35×10(8)/kg (range 0.59-14.07), the median CD34(+) cell count was 2.43×10(6)/kg (range 0.16-16.69). The CD34(+) cell count was higher than 1.00×10(6)/kg in 47 of 57 cases (82.46%) and higher than 2.00×10(6)/kg in 36 cases (63.16%). The CD34(+) cell count was higher than 2.00×10(6)/kg in 27 collections (23.68%). The MNC count and the CD34(+) cell count were correlated with the bottom of WBC after docetaxel chemotherapy (r=0.364, 0.502, P=0.005, 0.000). The CD34(+) cell count was correlated with the MNC count (r=0.597, P=0.000). The mobilization and apheresis were well tolerated in all patients. Mild perioral numbness and numbness of hand or feet were observed in 3 cases. No serious adverse events were reported.

CONCLUSION

Mobilization of peripheral blood hematopoietic stem cell by combining docetaxel with G-CSF was effective and safety in breast cancer patients.

Stage specific gene expression of serpins and their cognate proteases during myeloid differentiation

Proteases and their serpin inhibitors are abundantly expressed in haemopoietic and peripheral blood cells. There is, however, relatively little information about the role played by serpins in the control of protease activity within these cells and in the pericellular region. The observation that mutations in the neutrophil elastase gene, which cause cyclic and severe congenital neutropenia, are associated with protease maldistribution gives some clue as to the potential importance of inhibitor proteins. To begin to address the role of protease/inhibitor balance in blood cells we used reverse transcription polymerase chain reaction to examine protease and serpin gene expression in mature peripheral blood cells, differentiating haemopoietic progenitors, leukaemic blasts and haemopoietic cell lines. The results demonstrate stage-specific expression of proteases together with widespread expression of intra- and extra-cellular serpins. The elastase inhibitors monocyte neutrophil elastase inhibitor (MNEI) and antitrypsin (AT) showed overlapping expression. MNEI is predominantly expressed in early haemopoietic progenitors while antitrypsin is mainly expressed in more mature myeloid precursors, peripheral blood granulocytes and mononuclear cells. Our results give an overall picture of serpin and protease gene expression and draws attention to the potential importance of elastase regulators at all stages of myelopoiesis.

Improved haematopoietic recovery following transplantation with ex vivo -expanded mobilized blood cells*

Infusions of ex vivo-expanded (EXE) mobilized blood cells have been explored to enhance haematopoietic recovery following high dose chemotherapy (HDT). However, prior studies have not consistently demonstrated improvements in trilineage haematopoietic recovery. Three cohorts of three patients with breast cancer received three cycles of repetitive HDT supported by either unmanipulated (UM) and/or EXE cells. Efficacy was assessed by an internal comparison of each patient's consecutive HDT cycles, and to 106 historical UM infusions. Twenty-one cycles were supported by EXE cells and six by UM cells alone. Infusions of EXE cells resulted in fewer days with an absolute neutrophil count (ANC) <0.1 x 10(9)/l (median 2 vs. 4 d, P = 0.002) and 3 d faster ANC recovery to >0.1 x 10(9)/l (median 5 vs. 8 d, P = 0.0002). This resulted in a major reduction in the incidence of febrile neutropenia compared with UM cycles (0% vs. 83%; P = 0.008) and in 66% of historical UM cycles (P = 0.01) and a marked reduction in hospital re-admission. There were also fewer platelet transfusions required (43% vs. 100%; P = 0.009). We conclude that EXE cells enhance both neutrophil and platelet recovery and reduce febrile neutropenia, platelet transfusion and hospital re-admission.

A phase II study of escalated-dose docetaxel with granulocyte colony-stimulating factor support in patients with advanced breast cancer

PURPOSE

Docetaxel is highly active in the treatment of patients with breast cancer. The principal dose-limiting toxicities of the 3-weekly regimen are neutropenia and febrile neutropenia. In a previous phase I dose-escalation study with granulocyte colony-stimulating factor (G-CSF) support, the recommended dose was determined to be docetaxel 160 mg/m(2) 3-weekly. The objectives of this phase II study were to determine the response rate and toxicity of this dose and schedule, given as first-line in patients with advanced breast cancer. Mobilisation of peripheral blood stem cells (PBSCs) was also investigated.

PATIENTS AND METHODS

Eligible women had metastatic breast cancer and were aged 18-75 years with ECOG performance status < or =2. Strict criteria for liver function were followed, and adjuvant chemotherapy must have been completed at least 6 months previously. Treatment was docetaxel 160 mg/m(2) over 60-90 min every 21 days with G-CSF 5 micro g/kg/day until neutrophil recovery, for up to six cycles. A 3-day corticosteroid prophylaxis was given. Bloods samples to determine PBSC levels [CD34+, granulocyte-macrophage colony-forming cells (GM-CFC) and burst-forming units-erythroid (BFU-E)] were taken on days 6, 8, 9 and 11 following docetaxel.

RESULTS

Twenty-five women with median age 50 years (range 35-66) were included. Seventeen (68%) had previously received adjuvant chemotherapy. In total, 112 cycles were delivered (median four per patient), with dose reductions required in 12.5% of cycles. G-CSF was given for a median of 6 days. The median neutrophil nadir was 0.5 x 10(9)/l and occurred a median 5 days after treatment. The median duration of grade 3 or 4 neutropenia was 2 days (range 1-7). Grade 4 neutropenia occurred in 44% of patients, but there was only one episode of febrile neutropenia. Five patients were taken off study due to toxicities that included oedema, neurosensory toxicity and asthenia. Confirmed partial response was seen in nine patients (37.5%; 95% confidence interval 19% to 59%). CD34+ cells, GM-CFC and BFU-E levels peaked at day 8 following docetaxel administration. The median CD34+ cell peak was 6.5 x 10(4)/ml, with only 20% of patients <2 x 10(4)/ml, a level below which leukapheresis is not usually attempted.

CONCLUSIONS

Docetaxel 160 mg/m(2) was delivered with G-CSF support with a very low rate of febrile neutropenia. Non-haematological toxicity was significant, causing five patients to go off study. Effective mobilisation of PBSCs was seen. The response rate of 37.5% was less than that obtained in first-line studies using standard-dose docetaxel 100 mg/m(2), suggesting that there is no additional benefit in dose escalation of this cytotoxic agent in breast cancer patients using this schedule.

Comparison of three methods of CD34+ cell enumeration in peripheral blood: dual-platform ISHAGE protocol versus single-platform, versus microvolume fluorimetry

BACKGROUND

Quantitation of peripheral blood (PB) CD34(+) cells is now an established method for timing PBPC harvesting. Recent refinements to the dual-platform ISHAGE gating strategy for CD34(+) cells has seen the introduction of microbeads to enable absolute counting of cells on a single instrument platform. This eliminates the need for total WBCC performed on an automated hematology analyzer and potentially increases the analytical precision of the methodology. At the same time, alternative methods for CD34(+) cell enumeration have started to emerge, notably microvolume fluorimetry, which forms the basis of the fully-automated STELLer CD34 method using the Imagn 2000.

METHODS

We performed a three-way evaluation of these methods. Sixty-eight samples of PB from 42 patients undergoing PBPC mobilization were analyzed by all three methods and correlations between all three calculated. The two-platform ISHAGE method was used as the reference method.

RESULTS

Precision and linearity of the single-platform and STELLer CD34 assays were excellent. Correlation with the dual-platform reference method was also excellent (single-platform method slope = 1.03, intercept = -0.03 and R(2) = 0.9325, STELLer CD34 assay slope = 0.827, intercept = 4.27, R(2) =0.8215). Bias, determined by Bland-Altman analysis, was 1.16 and -1.62 for single platform and STELLer CD34 assay respectively.

CONCLUSION

The three methods of CD34(+) cell enumeration gave equivalent results. The single-platform methodology negated the need for a separate white cell analyzer, while the STELLer CD34 methodology was technically the simplest.

CliniMACS CD34-selected cells to support multiple cycles of high-dose therapy

BACKGROUND

Traditionally, following high-dose therapy (HDT), unmanipulated autologous PBPC are infused. Alternatively, purified CD34+ cells can now be obtained by immunomagnetic separation using the CliniMACS device. Limited data currently exist examining hemopoietic recovery with such cells.

METHODS

Ten patients with advanced breast cancer had PBPC mobilized with docetaxel (100 mg/m2) and G-CSF (10 microg/kg per day), harvested and processed using the CliniMACS CD34-selection device and equally divided into three aliquots for cryopreservation. Unmanipulated 'back-up' cells were also collected on a separate day of the same mobilization, divided into three and cryopreserved. Patients subsequently received three cycles of HDT with cyclophosphamide (4 g/m2), thiotepa (300 mg/m2) and paclitaxel (175 mg/m2). The intent was for patients to receive CD34-selected cells to support each of the three cycles of HDT (i.e., 1/3 for each cycle). If, however, hemopoietic recovery was delayed after Cycle 1, 1/3 of the unmanipulated cells were infused following Cycle 2 and the remaining CD34-selected cells (2/3) were used to support Cycle 3.

RESULTS

PBPC from 10 patients underwent CD34-selection with a resulting median purity of 93% (range: 76-98%) and yield of 62% (range: 16-93%). Of the 10 patients, only two were able to be supported with CD34-selected cells for all three cycles of HDT. The remaining eight patients required unmanipulated 'back-up' cells to support Cycle 2. Three patients also required infusion of 'back-up' unmanipulated cells because of persistent neutropenia (n = 1) or thrombocytopenia (n = 2) following cycles initially supported by CD34-selected cells. The median number of CD34-selected cells (x 10(6)/kg) infused per cycle was 1.5 (0.7-2.6) (n = 20) and unselected cells was 1.7 (1.4-2.8) (n = 10). Comparing hemopoietic recovery between cycles of HDT supported by CD34-selected (n = 20) and unmanipulated cells (n = 10) there was a significant slowing with the CD34-selected cells; time to ANC > 1.0 = 13 days versus 10 days, platelets > 20 = 17 days versus 13 days, > 50 = 25 versus 17 days (all P values < 0.001). There was no correlation between the dose of CD34-selected cells infused and neutrophil/platelet recovery.

DISCUSSION

We have demonstrated that, although unmanipulated PBPC achieve rapid hemopoietic recovery (at modest CD34 doses of < or = 2.8 x 10(6)/kg), CliniMACS-selected CD34+ cells (in the doses utilized in this study of < or = 2.6 x 10(6)/kg) result in significantly prolonged recovery.

Isolex 300i CD34-selected cells to support multiple cycles of high-dose therapy

BACKGROUND

We have previously reported that repeated cycles of high-dose therapy (HDT), can be supported by unmanipulated autologous PBPC. Here we investigate whether purified CD34+ cells, obtained by immunomagnetic separation using the Isolex 300i device, can support such therapy.

METHODS

Twenty-nine consecutive patients with metastatic breast cancer had PBPC mobilized and harvested following chemotherapy and G-CSF (10 microg/kg per day). Patients with > 4.0 x 10(6)/kg CD34+ cells in the apheresis product underwent CD34-selection using the Isolex 300i (v2.0) device. All cells collected were equally divided into three aliquots and cryopreserved. Patients who did not achieve this threshold had unmanipulated cells collected and stored. Patients subsequently received three cycles of HDT with paclitaxel (175 mg/m2), thiotepa (300 mg/m2) and either ifosfamide (10 g/m2) or cyclophosphamide (4 g/m2). It was intended for patients to receive CD34-selected cells to support each of the three cycles of HDT (i.e 1/3 for each cycle) and to compare hemopoietic recovery between patients receiving CD34-selected cells or unmanipulated cells.

RESULTS

Thirteen of the 29 patients (45%) did not mobilize sufficient CD34+ cells to undergo CD34-selection. The remaining 16 patients underwent CD34-selection with a median purity of 84.3% (range: 16.3-96.1%) and yield of 34% (range: 1-60%). Fifteen of these patients proceeded to HDT and 42 of the planned 45 cycles were administered. Nine patients had all three HDT cycles supported by CD34-selected cells. The median number of CD34-selected cells (x 10(6)/kg) infused per cycle was 1.5 (range: 0.04-3.01). Three of the 15 patients required infusion of 'back-up' unmanipulated cells because of delayed neutrophil recovery. Of the 13 patients whose PBPCs did not undergo CD34+ cell selection, 11 proceeded to HDT with a median of 3.2 x 10(6)/kg (range: 2.0-4.4) unselected cells infused per cycle and 31 of 33 planned cycles were delivered. When hemopoietic recovery was compared between cycles of HDT supported by CD34-selected (n = 34) and unmanipulated cells (n = 31), there was a modest slowing in the patients receiving CD34-selected cells; time to ANC > 1.0 x 10(9)/L = 11 days versus 10 days (P = 0.0122) and platelets > 20 x 10(9)/L = 14 days versus 13 days (P = 0.0009). No difference in recovery to 50 x 10(9)/L was observed (P = 0.54).

CONCLUSION

We have demonstrated that Isolex 300i CD34-selected cells are capable of supporting multiple cycles of HDT. However, we were unable to acquire sufficient CD34+ cells to perform this processing in 45% (13/29) of patients and further improvements in yield are required to overcome the modest delay in neutrophil and platelet recovery.

Harvesting of autologous blood stem cells after a mobilising regimen with low-dose cyclophosphamide

Although high-dose cyclophosphamide (HD-CTX) is commonly used as a mobilising regimen for autologous peripheral blood stem cell (PBSC) collection, significant morbidity and insufficient harvesting may complicate the procedure. Alternative regimens and lower doses of cyclophosphamide (CTX) have been investigated as possible ways of overcoming these difficulties. Low-dose CTX (1.5 g/m2) was administered to 102 lymphoma patients as an autologous PBSC mobilising regimen. The collection of 6 x 10(6) CD34+ cells/kg was chosen as the target of the apheresis sessions, whereas 3 x 10(6)/kg were considered the minimum necessary to perform autologous stem cell transplantation (ASCT) safely. The apheretic sessions were started a median of eight days after CTX administration; a median of two aphereses was required. More than 6 x 10(6) CD34+ cells/kg were collected from 78 patients, between 3 and 6 x 10(6)/kg from 19, and fewer than 3 x 10(6)/kg from 5, two of whom underwent bone marrow harvesting and one a successful second PBSC harvesting session using the same mobilising regimen. Eighty-two patients underwent autografting, six of whom received a second transplant after relapse (five using autologous PBSCs coming from the first apheretic course). Low-dose CTX proved to be a safe and effective regimen for autologous PBSC mobilization and also compared favourably with alternative regimens in terms of the rate of harvesting insufficiency. This does not imply that low-dose CTX is the best mobilising regimen for all patients, and the identification of prognostic factors predicting mobilising potential may help in choosing the best individualised regimen.

A phase II trial of docetaxel for peripheral blood stem cell mobilization for patients with breast cancer and ovarian cancer

As docetaxel is known to have significant antineoplastic activity against breast and ovarian cancer, we explored its application as a peripheral blood stem cell mobilizing agent in 33 women with stage lll-IV ovarian carcinoma (n = 10) or stage ll-lV breast cancer (n = 23) who were in preparation for high-dose chemotherapy. Eleven patients had bone and/or bone marrow involvement with their disease. The median number of prior regimens received before mobilization was two (range 1-3). The three dose levels administered were 100 mg/m(2), 110 mg/m(2) and 120 mg/m(2). Patients received one dose of docetaxel in the outpatient setting followed by G-CSF (10 microg/kg/day) starting 4 days after docetaxel administration. Leukapheresis commenced when WBC >1.0 x 10(9)/l or when the WBC began to rise after reaching a nadir. Ninety-seven percent of patients began leukapheresis within 7-9 days after receiving docetaxel (range 7-10 days). The collection goal was >/=2 x 10(6) CD34(+) cells/kg. Twenty-seven (82%) patients reached this goal in a median of 2 leukapheresis days (range 1-3). No grade 2-4 nonhematologic toxicities were noted. Thirteen patients (55%) showed a WBC nadir >1.0 x 10(9)/l. None of the patients experienced neutropenic fever or required blood or platelet transfusion support. In conclusion, docetaxel + G-CSF is an effective, well-tolerated regimen for PBPC mobilization which can be safely administered in the outpatient setting with minimal toxicity.

Severe interstitial pneumonitis following high-dose cyclophosphamide, thiotepa and docetaxel: two case reports and a review of the literature

The use of high-dose chemotherapy for metastatic breast cancer has been an area of recent interest and the role of such treatment in the management of metastatic breast cancer is still to be defined. Multiple studies have suggested that such treatment can be given with minimal morbidity and mortality. We describe two cases of life-threatening interstitial pneumonitis, following high-dose chemotherapy (HDT) with cyclophosphamide, thiotepa and docetaxel with stem cell rescue given for metastatic breast cancer. The available relevant literature is reviewed.

Repetitive high-dose therapy with cyclophosphamide, thiotepa and docetaxel with peripheral blood progenitor cell and filgrastim support for metastatic and locally advanced breast cancer: results of a phase I study

This phase I study was designed to determine the optimal dosages of a novel repetitive high-dose therapy regimen for patients with metastatic breast cancer (MBC). The planned treatment was three cycles of high-dose cyclophosphamide, thiotepa and docetaxel delivered every 35 days with progressive dose-escalation in successive cohorts. Each cycle was supported by peripheral blood progenitor cells (PBPC) and filgrastim. Eighteen patients were entered into this trial. Of the planned 54 treatment cycles, 44 were delivered and 11 patients completed all three cycles. The dose-limiting toxicities were interstitial pneumonitis and mucositis with moderately severe diarrhea (n = 3) and rash (n = 3). There were no treatment-related deaths. Of the 17 patients with evaluable disease, 16 patients responded with six patients achieving a complete remission and an additional four patients achieving no detectable disease (negative restaging including PET scan) but a persistently abnormal bone scan. At a median follow-up of 12 months, median progression-free survival was 11 months with the median overall survival not reached. The recommended doses for phase II/III studies are cyclophosphamide (4 g/m2), thiotepa (300 mg/m2) and docetaxel (100 mg/m2).