Sustained decrease of peripheral lymphocytes after allogeneic blood stem cell aphereses

48 healthy donors underwent peripheral blood stem cell (PBSC) apheresis for allogeneic transplantation beginning on day 4 of G-CSF (2 × 5 μg/kg) mobilization. In one to four (median two) large-volume mononuclear cell aphereses, a median of 55.9 × 10⁹ of lymphocytes (range 21.0–109.2 × 10⁹) were collected, an amount comparable to lymphocyte numbers removed by therapeutic lymphaphereses in autoimmune diseases. Mean peripheral lymphocyte counts decreased from premobilization values of 2.31 × 10⁹/l to 1.31 × 10⁹/l at a median of 34 d (1 month) and 1.53 × 10⁹/l at a median of 327 d (11 months). The decrease in peripheral lymphocyte counts was significantly correlated with the number of lymphocytes removed and the number of aphereses. Neutrophil and platelet counts returned to normal values after 1 month whereas monocyte counts and haemoglobin concentrations were significantly decreased at 1 month but not at 11 months.     

Flow cytometric detection of cytomegalovirus antigen in peripheral blood cells after bone marrow transplantation

We report 13 normal peripheral blood stem cell (PBSC) donors who had a second PBSC collection for allogeneic transplantation performed after the first. The median interval between the first and second collection was 5 months. Mobilization was achieved with filgrastim (12 μg/kg/d). No significant difference was found in the median pre-apheresis leucocyte count (×10⁹/l) between the two donations (40.2 v 38.5; P  = 0.91). The median apheresis yield (×10⁶ CD34⁺ cells/litre blood processed, first apheresis) was also similar (28 v 27.3; P  = 0.91). Filgrastim-related adverse events were comparable. These data suggest that second PBSC collections are feasible, similarly tolerated and provide comparable apheresis yields.     

Collection of peripheral blood stem cells from normal donors 60 years of age or older

We report 14 normal peripheral blood stem cell (PBSC) donors ≥ 60 years of age who had cytokine mobilization followed by PBSC apheresis for allogeneic transplantation. Mobilization was achieved with filgrastim (6 μg/kg twice daily). Their median age was 63.5 years (range 60–77), and 43% had a positive medical history, mainly hypertension and/or cardiac problems. Their median pre-apheresis leucocyte count (×10⁹/l) was 38.6 (range 29.6–63.4). The median apheresis yield (×10⁶ CD34⁺ cells/litre blood processed, first apheresis) was 27.9 (range 1.6–54.8). The target cell dose (≥4& times; 10⁶ CD34⁺ cells/kg recipient) was reached with one procedure in eight (57%) donors. Filgrastim-related adverse events were acceptable and apheresis was well tolerated. When compared to younger donors (<60 years of age), a trend to a lower CD34⁺ apheresis yield and a requirement for more than one apheresis to achieve the collection target (≥4 ×10⁶ CD34⁺ cells/kg) was evident. Although older (≥60 years) donors seem to mobilize less effectively, these data suggest that PBSC collection from them is feasible and has an acceptable short-term safety profile.     

STEM CELL MOBILIzATION IN NORMAL DONORS FOR ALLOGENEIC TRANSPLANTATION: ANALYSIS OF SAFETY AND FACTORS AFFECTING EFFICACY

The use of peripheral blood stem cells instead of bone marrow as the source of haemopoietic cells for allogeneic transplantation is being increasingly explored. We have analysed data from 17 normal donors who underwent stem cell mobilization for allogeneic transplantation with an identical protocol using G-CSF at a dose of 10 μg/kg/d, with the first leukapheresis (LP) on the day following the fourth dose of G-CSF. Both G-CSF administration and leukapheresis were well tolerated. Donors underwent a median of two leukaphereses (range one to three) and a median of 6.80 × 10⁶ CD34⁺ cells/kg recipient weight (range 2.4–15.6 × 10⁶) were collected. The median number of CD34⁺ cells per kg donor weight was 6.05 × 10⁶, when corrected for a 12 litre leukapheresis, this gave a median total of 3.89 × 10⁶ CD34⁺ cells/kg donor weight. When analysed with respect to factors which might influence the efficacy of mobilization, male donors were associated with a superior yield. The median number of CD34⁺ cells/kg/LP harvested was 4.96 × 10⁶ in males and 2.79 × 10⁶ in females ( P <0.05). The results suggested that, given a recipient of 75 kg, in a male donor a single 12 litre leukapheresis should yield sufficient CD34⁺ cells (4 × 10⁶/kg), whereas a female donor would be likely to need two leukaphereses. Age was not found to affect donor yield. In summary, these data confirm that leukapheresis is a safe procedure in normal donors and suggest that males may be more efficient mobilizers of stem cells than females.     

Serum oncostatin M in multiple myeloma: association with prognostic factors

We report on five children with haematological malignancies who underwent allogeneic peripheral blood progenitor cell (PBPC) transplantation. PBPC were harvested from HLA-identical sibling donors after G-CSF (10 μg/kg/d s.c.) mobilization. Aphereses were carried out on day 5 after G-CSF using a Cobe Spectra blood cell separator. All PBPC allografts were cryopreserved before transplantation. The median of CD34⁺ cells and CD3⁺ cells infused were 14.1×10⁶/kg recipient body weight (range 4.92–22.3) and 2.40×10⁸/kg recipient body weight (range 0.54–4.82), respectively. Engraftment occurred in all cases. The median time to a neutrophil count >0.5×10⁹/l and a platelet count >20×10⁹/l were 15 and 14 d, respectively. The incidence of severe acute graft-versus-host disease was 20%. These data suggest that allogeneic PBPC transplantation might be an alternative to bone marrow transplantation in children.     

Intermediate-dose melphalan (IDM) combined with G-CSF (filgrastim) is an effective and safe induction therapy for autologous stem cell transplantation in multiple myeloma

Twenty-one previously untreated multiple myeloma (MM) patients and 10 previously treated patients with refractory or relapsed disease received two or three cycles of intermediate-dose melphalan (70 mg/m²) (IDM), administered intravenously every 6 weeks. Seven previously untreated patients received three and all other patients received two courses of IDM. The objective of the study was to reduce the toxicity of high-dose melphalan (140 mg/m²) (HDM) while maintaining its cytotoxic efficacy and secondly to ensure the possibility of collecting sufficient numbers of peripheral blood stem cells (PBSC) for transplantation. 18 (85%) previously untreated patients responded, of whom four achieved CR (18%). In addition five out of 10 previously treated patients with refractory or relapsed disease responded although bone marrow toxicity in this category was a major drawback. Toxicity was moderate, consisting of alopecia and moderate bone marrow suppression: the granulocyte count dropped below 0.5 × 10⁹/l and platelets below 25 × 10⁹/l for a median of 8 and 6 d, respectively. No serious infections occurred and the majority of patients attended the out-patient clinic. In 12/14 previously untreated patients sufficient peripheral blood CD34⁺ cells for harvest were present in the repopulation phase after the first IDM. In nine patients peripheral blood stem cells were collected and eight patients have undergone succesful transplantation.
Repeated IDM followed by filgrastim is highly effective in untreated MM and may be safely administered to reduce tumour load prior to PBSC collection. Autologous stem cells harvested after repeated IDM have a full long-term repopulating capacity.     

Transplantation of HLA-mismatched CD34+ selected cells in patients with advanced malignancies: severe immunodeficiency and related complications

This trial was designed to test the use of CD34⁺ selected haemopoietic stem cells (HSC) in HLA-mismatched donor–recipient pairs, following intensive conditioning with thiotepa, antilymphocyte globulin (ALG), cyclophosphamide and single-dose total-body irradiation (sTBI). 10 patients aged 16–50 with advanced malignancies and a two- or three-antigen mismatched family donor entered this study. Donor marrow and G-CSF primed peripheral blood cells were processed separately on CD34 columns (Ceprate). The median number of infused CD34⁺ cells were 5.66 × 10⁶/kg, with 0.55 × 10⁶/kg CD3⁺ cells. Nine patients received cyclosporin for graft-versus-host disease (GvHD) prophylaxis. Median neutrophil counts on day 21 were 2 × 10⁹/l with a median platelet count of 60 × 10⁹/l, but CD4 counts remained extremely depressed throughout the study. Acute GvHD was scored as grade 0–I in two patients, as grade II in seven, and grade III in one. Eight patients died at a median interval of 72 d from HSCT (range 20–144) due to cytomegalovirus (CMV) associated interstitial pneumonitis (IP) ( n  = 5), renal failure ( n  = 1), GvHD ( n  = 1) and Aspergillus meningitis ( n  = 1). Two patients are alive 365–495 d post transplant, one in remission and one in relapse.
This study suggests that large numbers of positively selected mismatched HSC can rapidly engraft after intensive conditioning regimen: however, profound post-transplant immunodeficiency leads to a high risk of lethal infectious complications.     

Successful treatment of chronic severe neutropenia with weekly recombinant granulcyte-colony stimulating factor

Daily treatment for symptomatic chronic neutropenia with recombinant granulocyte-colony stimulating factor (rhG-CSF) filgrastim is costly and sometimes causes neutrophillia. We report the use of weekly filgrastim in a 40-year-old man with life-long symptomatic neutropenia. Baseline neutrophil counts were <1×10⁹/l 60% of the time, and fell below 0.5×10⁹/l for 7 d periods every 22 d. Following 1 year of weekly filgrastim treatment, the absolute neutrophil count was maintained >1×10⁹/l (averaging 2×10⁹/l) and the frequency and severity of symptoms were reduced by 85%. Therefore the benefits of filgrastim for the treatment of at least one form of chronic severe neutropenia can be derived from weekly rather than daily doses.     

Evaluation of a new, integral, whole blood filter (RS2000) system for prestorage leucodepletion of SAG-M red cells

Residual donor leucocytes are responsible for many adverse transfusion reactions. Prestorage leucodepletion may ameliorate these effects and enhance product quality. We studied a bottom and top (BAT) system incorporating an integral filter for whole blood leucodepletion. Our evaluation assessed leucodepletion efficiency as well as in vitro SAG-M red cell quality and storage characteristics.   Sixty-six units of blood were collected; test units into the Optipac^®- p L u S system and controls into the standard triple pack configuration. Test units were held for 4–6 h at room temperature (rt) or 12–18 h at 4°C. The mean leucocyte counts for the SAG-M red cells in the quality and storage trial were 0.6×10⁶ (rt hold), 0.05×10⁶ (4°C hold) and 2500×10⁶ (controls). We observed no significant differences between the groups for Na⁺, ATP, 2,3-DPG, glucose, lactate and pH during the 49 d storage. The control group, however, showed a greater increase in haemolysis and K⁺ with time. Autologous in vivo 24 h red cell recovery, after 42 d storage, was >75%. Adjustment of processing parameters in subsequent studies gave leucodepleted SAG-M red cells with minimal cell loss (9–19%) plus acceptable haemoglobin content (46–76 g/U) and haematocrit (54–62%). This system achieved >3.5 log leucodepletion with all but one unit containing <1×10⁶ leucocytes. The product quality is good and the system suitable for routine use in blood centres.     

COLLECTION AND TRANSPLANTATION OF PERIPHERAL BLOOD PROGENITOR CELLS MOBILIzED BY G-CSF ALONE IN CHILDREN WITH MALIGNANCIES

Results of collection and transplantation of peripheral blood progenitor cells (PBPC) mobilized by G-CSF in 31 children with different malignancies were analysed. A total of 43 aphereses were performed, following administration of granulocyte colony-stimulating factor (G-CSF), using a continuous flow blood cell separator (Cobe Spectra) through a central venous catheter. For patients weighing ≤25 kg the extracorporeal line was primed with red blood cells. The mean blood flow rate was 33.2ml/min (range 12–56ml/min). The mean number of mononuclear cells (MNC), granulocyte-macrophage colony-forming units (CFU-GM) and CD34⁺ cells collected were 7.22×10⁸/kg body weight (b.w.), 15.9×10⁴/kg and 5.44×10⁶/kg respectively.
The morbidity related to PBPC collection was low and the mean apheresis time was 302.7min (range 115–492). The volume of processed blood for apheresis (per kilogram body weight) ranged from 117 to 539.6 (mean 309.13ml/kg). 20 patients required only one apheresis to collect the minimum requirement of 5–7×10⁸/kg of MNC.
All patients subsequently underwent autografting with PBPC after myeloablative therapy. Days to achieve an absolute count of neutrophils (ANC) <0.5×10⁹/l and a platelet count of 20×10⁹2/l without platelet support were 9.5 and 18, respectively. The number of CD34⁺ cells infused correlated highly with engraftment kinetics. The extramedullary toxicity was low and manageable.     

Feasibility of peripheral blood progenitor cell harvest and transplantation in patients with poor-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of clonal haematological disorders with a highly unfavourable prognosis. Allogeneic bone marrow transplantation offers the sole possibility for cure and prolonged survival, but is only available for a minority of patients. Therefore, we investigated the feasibility of PBPC collection and transplantation in 11 patients with high-risk myelodysplasia who were not eligible for allogeneic bone marrow transplantation. In six patients, PBPC were harvested after mobilization with G-CSF alone. Five patients were harvested during the recovery phase of intensive chemotherapy combined with G-CSF. This resulted in seven patients in an adequate CD34 progenitor yield >1 × 10⁶/kg. Six patients obtained a CFU-GM content of the PBPC harvest >10 ×10⁴/kg. Five patients were subsequently transplanted following a standard BuCy4 regimen. The median to ANC (absolute neutrophil count) ≥0.5 and 1.0 × 10⁹/l was respectively 14 d (range 10–18) and 16 d (range 11–25). Platelets were self-supporting ≥20 × 10⁹/l after a median of 41 d (range 8–144). One patient had a persistent lack of platelet engraftment unresponsive to infusion of back-up bone marrow.
These data demonstrate that in selected patients with high-risk MDS, adequate PBPC collection appears feasible, enabling the harvest of sufficient cell numbers required for rapid and stable engraftment after reinfusion. Improvement in mobilization efficiency may enable the collection of higher CD34⁺ progenitor cell numbers required for more rapid platelet engraftment. PBPC transplantation may be an alternative treatment option for patients who lack an allogeneic marrow donor. Follow-up is, however, still too limited to draw any conclusion regarding the long-term cure rate.     

Increased number of peripheral blood CD34+ cells in lithium-treated patients

Eight adult patients with bipolar disorder were prospectively examined to find whether lithium carbonate increased their peripheral blood CD34⁺ haemopoietic stem cells. Following lithium therapy for 3–4 weeks their neutrophil counts increased by a mean of 88% (from 4625 ± 1350 × 10⁹/l, mean ± SD pretreatment, to a peak of 8300 ± 3910 × 10⁹/l). Concommitantly, there was a significant increment in their CD34⁺ cells (from 0.11 ± 0.01% to a peak of 0.18 ± 0.08%). There was a significant correlation between the rise in neutrophil count and that of the CD34⁺ cells ( r  = 0.795, P  = 0.019). Lithium therapy may be used to mobilize peripheral blood CD34⁺ cells for marrow transplantation.     

Blood neutrophil increment after a single injection of rhG-CSF or rhGM-CSF correlates with marrow cellularity and may predict the grade of neutropenia after chemotherapy

Summary. The grade of neutropenia after chemotherapy seems to be correlated to the bone marrow cellularity as judged by biopsies. Prolonged blood neutropenia after sequential chemotherapy reduces dose intensity and increases the risk of severe infections. A predictive non-invasive test for marrow cellularity is needed in the attempt to predict chemotherapy-induced blood neutropenia.
Thirty-one patients with haematological disorders were studied with measurements of blood absolute neutrophil counts (ANC) 24 h after a single subcutaneous injection of recombinant human granulocyte colony stimulating factor (rhG-CSF) or granulocyte-macrophage CSF (rhGM-CSF). Before cytokine administration all patients had bone marrow biopsies performed.
The median increase in blood ANC 24 h after cytokine administration was 15·9 × 10⁹/l (range 3·7–34·2) in 18 patients with normo- or hypercellular marrows and only 0·4 × 10⁹/l (range 0·0–11·2) in 13 patients with hypocellular marrows ( P <0·00001). An increase in ANC or more than 5 × 10⁹/l was predictive for normo- or hypercellular bone marrows with a sensitivity and specificity of 94% and 84%, respectively.
A subsequent pilot study in selected patients with prolonged neutropenia was performed. The ANC increment in 12 cases before chemotherapy correlated to the grade of neutropenia and may predict the risk of febrile neutropenia.
It is suggested that blood responsiveness to myeloid growth factors correlates with marrow cellularity and may identify outpatients with risk for severe neutropenia after cyclic chemotherapy.     

G-CSF alone mobilizes sufficient peripheral blood CD34+ cells for positive selection in newly diagnosed patients with myeloma and lymphoma

We have evaluated CD34⁺ cell positive selection from granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPC) in 26 patients with either multiple myeloma (MM, n  = 18) or follicular non-Hodgkin's lymphoma (NHL, n  = 8). 26 PBPC were collected with two leukaphereses: 16 contained sufficient numbers of CD34⁺ cells and were selected. The absolute number of CD34⁺ cells in the leukapheresis products was found to be significantly related to the duration of underlying disease and exposure to prior treatment. CD34⁺ cell positive selection allowed recovery of a median of 35% of CD34⁺ cells, the selected fraction containing a median number of 1.43 × 10⁶/kg CD34⁺ cells/kg (range 0.48–41.5). 10 patients were transplanted and received a median dose of 1.51 × 10⁶ CD34⁺ cells (range 0.48–4.2). The median time to granulocyte (>0.5 × 10⁹/l) and platelet (>20 × 10⁹/l) engraftment was 12 and 13 d respectively (ranges 10–13 and 0–95). Lymphoma cells were found by a sensitive polymerase chain reaction technique in four out of five CD34⁺ cell fractions tested.     

Clinical characteristics predict response to antithymocyte globulin in paroxysmal nocturnal haemoglobinuria

Seven patients with paroxysmal nocturnal haemoglobinuria (PNH) were treated with antithymocyte globulin (ATG). Each patient received ATG (20 mg/kg/d) for 8 d and prednisone to prevent or control serum sickness. Three patients experienced a sustained improvement in at least one peripheral blood cytopenia, including one patient who had a complete trilineage response. Several pre-treatment clinical features appeared to be associated with response to ATG. All responding patients had hypoproliferative features including depressed platelet counts (<30×10⁹/l), and a minor degree of chronic haemolysis as indicated by relatively low reticulocyte counts (<100×10⁹/l), lactate dehydrogenase (<1000 U/l) and total bilirubin (<17μmol/l) levels. Responding patients continued to have chronic low-grade haemolysis after their response to immunosuppression that was similar to that observed prior to treatment. The non-responding patients had a classic haemolytic form of PNH characterized by elevated reticulocyte counts (>100×10⁹/l), lactate dehydrogenase (>2000 U/l) and total bilirubin (>17μmol/l) levels.
The impaired haemopoiesis that occurs in hypoproliferative PNH may respond to ATG treatment, but the haemolytic component of the disease, and hence the PNH clone, is not altered by immunosuppressive therapy.     

The risk of spinal haematoma following neuraxial anaesthesia or lumbar puncture in thrombocytopenic individuals

Neuraxial anaesthesia is increasingly performed in thrombocytopenic patients at the time of delivery of pregnancy. There is a lack of data regarding the optimum platelet count at which spinal procedures can be safely performed. Reports are often confounded by the presence of other risk factors for spinal haematomata, such as anticoagulants, antiplatelet agents and other acquired or congenital coagulopathies/platelet function defects or rapidly falling platelet counts. In the absence of these additional risk factors, a platelet count of 80 × 10⁹/l is a 'safe' count for placing an epidural or spinal anaesthetic and 40 × 10⁹/l is a 'safe' count for lumbar puncture. It is likely that lower platelet counts may also be safe but there is insufficient published evidence to make recommendations for lower levels at this stage. For patients with platelet counts of 50–80 × 10⁹/l requiring epidural or spinal anaesthesia and patients with a platelet count 20–40 × 10⁹/l requiring a lumbar puncture, an individual decision based on assessment of risks and benefits should be made.     

Granulocyte colony-stimulating factor given in addition to interferon-α to mobilize peripheral blood stem cells for autologous transplantation in chronic myeloid leukaemia

In order to potentially mobilize and harvest the Ph⁻ cells observed in most patients with chronic myeloid leukaemia (CML) during interferon-α (IF-α) therapy, G-CSF (filgrastim), 5 μg/kg/d, was administered subcutaneously together with IF-α to 30 CML patients in haematological remission but with various degrees of cytogenetic remission, after IF-α therapy. Peripheral blood stem cells (PBSC ) were harvested using standard aphereses from day 5 of G-CSF. Patients underwent one to four (median three) aphereses. Median total yields/kg were 7.6 (range 3.8–25) × 10⁸ MNC, 3.4 (0–140) × 10⁶ CD34⁺ cells, and 17 (1.1–107) × 10⁴ CFU-GM. No patient had a significant increase in the percentage of Ph⁺ cells in the bone marrow under G-CSF therapy. The percentage of Ph⁺ cells in apheresis products tended to decrease between the first and the last apheresis ( P  = 0.05). 14 patients who were not responsive to IF-α were transplanted after conditioning with busulphan 16 mg/kg and melphalan 140 mg/m². Median time to neutrophils > 0.5 × 10⁹/l was 20 d (16–114 d) and to platelets > 50 × 10⁹/l 18 d (12–149 d). Nine patients had a major cytogenetic response post graft, which correlated with the amount of Ph⁺ cells reinfused with the graft ( P  = 0.02). We conclude that this procedure is feasible, allowing the harvest of enough PBSC, some of them Ph⁻ in patients who responded to IF-α, to allow autologous transplantation.     

Progenitor cell subsets and engraftment kinetics in children undergoing autologous peripheral blood stem cell transplantation

The main objective of the present study was to determine the role of CD34⁺ cell subsets in the haemopoietic recovery of children undergoing peripheral blood stem cell transplantation. For this purpose, 38 leukaphereses from 33 children with malignancies mobilized with G-CSF were analysed. Using dual-colour flow cytometry, different subpopulations of CD34⁺ cells were quantified and the number of each reinfused subsets correlated with haemopoietic resurgence. Multivariate analysis showed that the number of CD34⁺CD38⁻ cells and CD34⁺CD38⁺ cells correlated better with time to neutrophil and platelet recovery, respectively, than the total number of CD34⁺ cells. Threshold values for rapid haemopoietic recovery, determined by the receiver operating characteristic analysis, were found to be 0.5 × 10⁶ CD34⁺CD38⁻ cells for neutrophil engraftment, and 2.0 × 10⁶ CD34⁺CD38⁺ cells for platelet recovery. It is suggested that the analysis of CD34⁺ cell subsets could increase understanding of the repopulation capacity of a given leukapheresis product in peripheral blood stem cell transplantation procedures in children. In particular, this procedure could be extremely useful when low numbers of CD34⁺ cells are collected.     

A randomized phase II study of BB-10010: a variant of human macrophage inflammatory protein-1α for patients receiving high-dose etoposide and cyclophosphamide for malignant lymphoma and breast cancer

Macrophage inflammatory protein-1α (MIP-1α) is a chemokine that can inhibit the cell cycle progression of both primitive haemopoietic and epidermal progenitor cells. This property could potentially be exploited to attenuate both the myelosuppressive effects of chemotherapy as well as mucositis. We evaluated both the biological and clinical effects of BB-10010, a genetically engineered variant of MIP-1α, in patients with malignant lymphoma or breast cancer receiving high-dose etoposide (VP 3.6 g/m²) and cyclophosphamide (Cy 200 mg/kg). 52 patients were randomized to one of three cohorts. Cohort A received no BB-10010; cohorts B and C received 10 μg/kg and 100 μg/kg of BB-10010, respectively. All patients received post-chemotherapy G-CSF. BB-10010 was well tolerated. There were no significant differences between groups in recovery to an ANC > 0.5 × 10⁹/l, 1 × 10⁹/l or 1.5 × 10⁹/l, the number of days with an ANC < 0.5 × 10⁹/l, days to a platelet count >50 × 10⁹/l or 100 × 10⁹/l, or the incidence and severity of mucositis. There was no evidence of any effect of BB-10010 on colony-forming cell (CFC) or long-term culture-initiating cell (LTC-IC) mobilization, cycling activity in the marrow or on chemotherapy-induced changes in CFC or LTC-IC number both of which were in the normal range by 22 d after completion of the chemotherapy. To our knowledge this is the first report of a myelointensive regimen having no apparent long-term effect on the LTC-IC compartment. In summary, BB-10010 is safe when used in patients receiving high-dose therapy but has no effect on reducing the toxicity of such therapy.     

Intensive chemotherapy with blood progenitor transplantation for primary resistant multiple myeloma

Summary. This study assessed the feasibility and effect of blood progenitors as the only source of haemopoietic support for myeloablative therapy for patients with primary resistant multiple myeloma and markedly infiltrated bone marrow. 17 patients with advanced, primary resistant myeloma received a priming regimen of cyclophosphamide (3 g/m²) and etoposide (900 mg/m²) with GM-CSF. During haematological recovery, at least 2 × 10⁶ CD34⁺ mononuclear cells/kg were collected from each patient with 4-12 leukaphereses. High-dose chemotherapy was then given which consisted of thiotepa (750 mg/m²), busulfan (10 mg/kg) and cyclophosphamide (120 mg/kg) followed by reinfusion of the blood progenitors. Haemopoietic reconstitution was rapid with recovery of granulocytes to >1.0 × 10⁹/1 after a median of 10 d and of platelets to 50 × 10⁹/1 after a median of 29 d. The myeloma responded in 10/17 patients for a projected median duration of at least 12 months. Survival was prolonged significantly in comparison with the outcome of control patients who did not receive intensive treatment. Blood progenitors, assessed from the number of CD34⁺ cells, produced early haemopoietic recovery after myeloablative therapy that induced sustained control of advanced and resistant multiple myeloma.