Randomized trial of low-dose interleukin-2 vs cyclosporine A and interferon-gamma after high-dose chemotherapy with peripheral blood progenitor support in women with high-risk primary breast cancer.

High-risk primary breast cancer patients treated with high-dose chemotherapy (HDC) and stem cell support (SCS) have shown prolonged disease-free survival (DFS) in many studies; however, only one trial has demonstrated an overall survival benefit (OS). We hypothesize that the period following myeloablative therapy is ideal for immunologic manipulation and studied the effects of two different methods of immunotherapy following HDC with SCS aimed at the window of immune reconstitution. Seventy-two women with high-risk stage II or III breast cancer were randomized following HDC to receive either interleukin 2 (IL-2) at 1 million units/m(2) SQ daily for 28 days or combined cyclosporine A (CsA) at 1.25 mg/kg intravenously daily from day 0 to +28 and interferon gamma (IFN-gamma) 0.025 mg/m(2) SQ every 2 days from day +7 to +28. At a median follow-up of 67 months, no significant difference was observed in DFS or OS between the two treatment groups. The IL-2 arm had a 59% DFS (95% CI (0.45, 0.78)) and a 72% OS (95% CI (0.58, 0.88)) at 5 years. The CsA/INF-gamma arm had a similar outcome with a 55% DFS (95% CI (0.40, 0.76)) and a 78% OS (95% CI (0.65, 0.94)) at 5 years. Treatment was well tolerated, without increased toxicity.

Allogeneic stem cell transplantation corrects biochemical derangements in MNGIE.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a multisystemic autosomal recessive disease due to primary thymidine phosphorylase (TP) deficiency. To restore TP activity, we performed reduced intensity allogeneic stem cell transplantations (alloSCTs) in two patients. In the first, alloSCT failed to engraft, but the second achieved mixed donor chimerism, which partially restored buffy coat TP activity and lowered plasma nucleosides. Thus, alloSCT can correct biochemical abnormalities in the blood of patients with MNGIE, but clinical efficacy remains unproven.

Phase I/II study of tandem cycles of high-dose chemotherapy followed by autologous hematopoietic stem cell support in women with advanced ovarian cancer.

The objectives of this study were to investigate the tolerability of a novel high-dose chemotherapy (HDC) regimen with peripheral blood progenitor cell (PBPC) support in patients with pretreated advanced ovarian cancer and to determine the maximum-tolerated dose (MTD) of topotecan in this setting. Advanced ovarian cancer patients previously treated with platinum-based first-line therapy were enrolled. After PBPC mobilization and harvesting, patients received three consecutive cycles of HDC with PBPC support. Cycle 1 was carboplatin area under the concentration curve 20 and paclitaxel 250 mg/m(2). Cycle 2 was topotecan starting at 5 mg/m(2), dose escalated in 2 mg/m(2) increments, and etoposide 600 mg/m(2). Cycle 3 was thiotepa 500 mg/m(2). After each cycle, PBPCs were infused. Granulocyte colony stimulating factor (5 microg/kg/day) was administered until neutrophil recovery occurred. Seventeen patients were enrolled; all were safety evaluable. The most common nonhematologic toxicity was grade 3 mucositis (44%). Engraftment of PBPCs was successful in all patients after each cycle, and no treatment-related deaths occurred. Of 14 patients with measurable disease, 5 (36%) had complete responses, 2 (14%) had partial responses, and 4 (29%) had stable disease. The median progression-free and overall survivals were 7 and 18 months, respectively. The MTD of topotecan was not reached. The tolerability and activity of this regimen in patients with advanced ovarian cancer warrant further investigation.

Pilot study of tandem high-dose chemotherapy and autologous stem cell transplantation with a novel combination of regimens in patients with poor risk lymphoma.

In an effort to improve the outcome of poor-risk lymphoma patients, we evaluated a novel regimen of tandem high-dose chemotherapy (THDC) with autologous stem cell transplantation. A total of 41 patients (median age 40 years, range 15-68 years) with poor-risk non-Hodgkin's lymphoma and Hodgkin's disease were enrolled. THDC consisted of melphalan (180 mg/m2) and escalating dose mitoxantrone (30-50 mg/m2) (MMt) for the first conditioning regimen, and thiotepa (500 mg/m2), carboplatin (800 mg/m2), and escalating dose etoposide phosphate (400-850 mg/m2), (ETCb) as the second regimen. In all, 31 patients (76%) completed both transplants, with a median time between transplants of 55 days (range 26-120). The maximum tolerated dose was determined as 40 mg/m2 for mitoxantrone and 550 mg/m2 for etoposide phosphate. The overall toxic death rate was 12%. Following high-dose chemotherapy, 10 of 24 evaluable patients (42%) were in CR. The two-year overall survival and event-free survival is 67% (95% CI, 52-81%) and 45%, (95% CI, 29-61%) for the 41 patients enrolled; and 69% (95% CI, 525-586%) and 48% (95% CI, 30-67%) for the 31 patients completing both transplants. This THDC regimen is feasible but with notable toxicity in heavily pretreated patients; its role in the current treatment of high-risk lymphoma remains to be determined.

Glutamine as a neuroprotective agent in high-dose paclitaxel-induced peripheral neuropathy: a clinical and electrophysiologic study.

AIMS: The appearance of peripheral neuropathy is the dose-limiting toxicity in many chemotherapy protocols, and glutamine has been proposed as a potentially neuroprotective agent in patients receiving paclitaxel. MATERIALS AND METHODS: In this non-randomised study, we assessed neurologic signs and symptoms, and changes in nerve-conduction studies in 46 consecutive patients given high-dose paclitaxel either with (n=17) or without (n=29) glutamine. Neurological assessments and electrodiagnostic studies were carried out at baseline and at least 2 weeks (median 32 days) after treatment. RESULTS: Patients who received glutamine developed significantly less weakness (P = 0.02), less loss of vibratory sensation (P = 0.04) and less toe numbness (P = 0.004) than controls. The per cent change in the compound motor action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes after paclitaxel treatment was lower in the glutamine group, but this finding was not statistically significant in these small groups. CONCLUSIONS: In this study, serial neurologic assessment of patient symptoms and signs seemed to be a better indicator of a possible glutamine effect than sensory- or motor-nerve-conduction studies. Prospective randomised trials are needed to clarify the effect of glutamine on paclitaxel and other types of chemotherapy-induced neuropathy.

Therapy-related myelodysplastic syndrome after autologous stem cell transplantation for breast cancer.

Therapy-related myelodysplastic syndrome and acute myelogenous leukemia (t-MDS/AML) are serious complications of chemotherapy and radiotherapy for cancer. High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) may be associated with an increased incidence of these complications. The frequency of t-MDS/AML after ASCT for breast cancer is uncertain. We reviewed our database of 379 consecutive breast cancer ASCT patients treated with alkylator-based chemotherapy, followed for a median of 1.52 years (range 0-8.97), with a median survival of 6.16 years. Three patients have developed tMDS/AML. The probability of developing this complication at 5 years is 0.032 in our series. We have used pathologic, cytogenetic and molecular methods to evaluate which portions of therapy may have predisposed to the development of this complication. Cytogenetic abnormalities were not found in the stem cell harvests of these patients by metaphase analysis or by fluorescence in situ hybridization (FISH). One patient demonstrated a clonal X chromosome inactivation pattern in her stem cell harvest, indicating pre-transplant chemotherapy may have been responsible for the development of her leukemia. As two of our patients developed this complication at greater than 4 years post-transplant, the number of cases may increase with longer follow-up. While the incidence appears to be low, further prospective and retrospective analysis will be necessary to determine which portions of therapy predispose to the development of t-MDS/AML in patients undergoing ASCT for treatment of breast cancer.

Phase II trial of sequential high-dose chemotherapy with paclitaxel, melphalan and cyclophosphamide, thiotepa and carboplatin with peripheral blood progenitor support in women with responding metastatic breast cancer.

A single high-dose cycle of chemotherapy can produce response rates in excess of 50%. However, disease-free survival (DFS) is 15-20% at 5 years. The single most important predictor of prolonged DFS is achieving a complete response (CR). Increasing the proportion of patients who achieve a complete response may improve disease-free survival. Women with metastatic breast cancer and at least a partial response (PR) to induction chemotherapy received three separate high-dose cycles of chemotherapy with peripheral blood progenitor support and G-CSF. The first intensification was paclitaxel (825 mg/m(2)), the second melphalan (180 mg/m(2)) and the third consisted of cyclophosphamide 6000 mg/m(2) (1500 mg/m(2)/day x 4), thiotepa 500 mg/m(2) (125 mg/m(2)/day x 4) and carboplatin 800 mg/m(2) (200 mg/m(2)/day x 4) (CTCb). Sixty-one women were enrolled and 60 completed all three cycles. Following the paclitaxel infusion most patients developed a reversible, predominantly sensory polyneuropathy. Of the 30 patients with measurable disease, 12 converted to CR, nine converted to a PR*, and five had a further PR, giving an overall response rate of 87%. The toxic death rate was 5%. No patient progressed on study. Thirty percent are progression-free with a median follow-up of 31 months (range 1-43 months) and overall survival is 61%. Three sequential high-dose cycles of chemotherapy are feasible and resulted in a high response rate. The challenge continues to be maintenance of response and provides the opportunity to evaluate strategies for eliminating minimal residual disease.

Membranous glomerulopathy associated with graft-versus-host disease following allogeneic stem cell transplantation. Report of 2 cases and review of the literature.

We report two cases of nephrotic syndrome presenting 18 and 20 months after allogeneic stem cell transplantation (alloSCT) with chronic myelogenous leukemia. Both patients had acute and chronic graft-versus-host disease (GVHD) and renal biopsy findings of membranous glomerulopathy (MG). A review of the literature revealed 10 additional cases of immune-complex-mediated glomerular disease following alloSCT, 8 of which were diagnostic of MG. All patients showed evidence of acute or chronic GVHD. Patients typically presented with preserved renal function (mean creatinine 1.2 mg/dl) and full nephrotic syndrome including heavy proteinuria (mean 9.2 g/24 h), edema, hypoalbuminemia (mean 2.1 g/dl) and hypercholesterolemia (mean 472 mg/dl). Most patients showed stabilization of renal function and significant decreases in proteinuria when treated with steroids and/or cyclosporine. The close temporal association as well as evidence from murine models of GVHD support a pathogenetic association between GVHD and the development of MG.

Tandem transplantation in lymphoma.

The majority of poor-risk lymphoma patients are not cured with conventional chemotherapy. There is evidence for the superiority of single high-dose chemotherapy in such patients, but many still die from recurrent disease. Strategies to improve survival in these poor-risk patients include dose-intensification with high-dose chemotherapy and PBPC support, tandem autologous HDC with PBPC support, and autologous followed by non-myeloablative allogeneic transplantation. These more aggressive strategies are feasible and tolerable. Whether tandem transplantation will prove more effective than current single high-dose therapy in appropriately selected patients remains to be determined.

Transcript profiling of human dendritic cells maturation-induced under defined culture conditions: comparison of the effects of tumour necrosis factor alpha, soluble CD40 ligand trimer and interferon gamma.

Using cDNA arrays, we characterized patterns of gene expression in populations of human dendritic cells (DCs) produced for clinical use. Culture and maturation induction of myeloid adherent cells under serum-free conditions yielded DCs with phenotypes similar to those described in serum-based systems. Analysis of gene expression in DCs treated with tumour necrosis factor alpha, soluble CD40L trimer or interferon gamma, however, showed specific patterns for each factor examined. Our studies document the expression of several transcripts that have not hitherto been described in DCs and/or differentially regulated according to the differentiation state of the DCs, and suggest important functional differences among the DC populations examined. In addition, DC maturation directs changes in the levels of mRNA specific for transcriptional regulators that effect the production of cytokines (e.g. BCL-6, c-rel). Other changes observed, including alteration in the gene expression profile of adhesion molecules and chemokine receptors such as CD44H, CD 49B, Rantes R, CXCR5 and CD37, suggest differences in trafficking potential between the populations studied. This broad-based description of DC populations, produced under serum-free conditions, has enabled us to better define intermediate stages of DC maturation as well as the differentiation-inducing effects of cytokines on these cells.

Reduction of paclitaxel-induced peripheral neuropathy with glutamine.

PURPOSE: Dose-limiting toxicity of many newer chemotherapeutic agents is peripheral neuropathy. Prior attempts to reduce this side effect have been unsuccessful. We report on the possible successful reduction of peripheral neuropathy with glutamine administration after high-dose paclitaxel. EXPERIMENTAL DESIGN: Patients entered a high-dose chemotherapy protocol in which the first high-dose cycle was paclitaxel at 825 mg/m(2) given over 24 h. The first cohort of patients did not receive glutamine, and the second cohort of patients received glutamine at 10 g orally three times a day for 4 days starting 24 h after completion of paclitaxel. Neurological assessment was performed at baseline, and at least 2 weeks after paclitaxel, and consisted of a complete neurological exam and nerve conduction studies. RESULTS: There were paired pre- and post-paclitaxel evaluations on 33 patients who did not receive glutamine and 12 patients who did. The median interval between pre- and post-exams was 32 days. For patients who received glutamine, there was a statistically significant reduction in the severity of peripheral neuropathy as measured by development of moderate to severe dysesthesias and numbness in the fingers and toes (P < 0.05). The degree and incidence of motor weakness was reduced (56 versus 25%; P = 0.04) as well as deterioration in gait (85 versus 45%; P = 0.016) and interference with activities of daily living (85 versus 27%; P = 0.001). Moderate to severe paresthesias in the fingers and toes were also reduced (55 versus 42% and 64 versus 50%, respectively), although this value was not statistically significant. All of these toxicities were reversible over time. CONCLUSIONS: Glutamine may reduce the severity of peripheral neuropathy associated with high-dose paclitaxel; however, results from randomized, placebo-controlled clinical trials will be needed to fully assess its impact, if any. Trials are currently ongoing to assess its efficacy for standard-dose paclitaxel in breast cancer and other tumors for which peripheral neuropathy is the dose-limiting toxicity.

The pharmacokinetics and pharmacodynamics of high-dose paclitaxel monotherapy (825 mg/m2 continuous infusion over 24 h) with hematopoietic support in women with metastatic breast cancer.

PURPOSE: We evaluated the pharmacokinetics and pharmacodynamics of high-dose paclitaxel (HDP) monotherapy (825 mg/m2 continuous infusion over 24 h) with peripheral blood progenitor cell (PBPC) and G-CSF support in 17 women with metastatic breast cancer. METHODS: Pharmacokinetic and pharmacodynamic data were collected in 17 women entered in a phase II trial of sequential HDP, and high-dose melphalan and cyclophosphamide/thiotepa/carboplatin. RESULTS: The maximal plasma concentration (Cmax), area under the plasma concentration time curve (AUC), apparent clearance (Clapp), duration of plasma concentration above 0.05 microM (t > 0.05 microM) for paclitaxel were (means SD): 9.11 +/- 7.45 microM, 145 +/- 88 microM x h, 8.06 +/- 2.90 l/h per m2 and 82.4 +/- 31.2 h, respectively. There was a significant correlation between the plasma paclitaxel concentration at 1 h (r2 = 0.87), 12 h (r2 = 0.85) and 23 h (r2 =0.92) and the AUC (P < 0.0001). Duration of neutropenia was brief (median 3 days, range 0-5 days) and neutrophil recovery occurred earlier (median 6 days, range 0-7 days) than could be attributed to infused PBPC. Median nadir count for platelets was 66 x 10(9)/l (range 13-160 x 10(9)/l). Pharmacodynamic analysis showed no correlation between pharmacokinetic parameters (Cmax, AUC, t > 0.05 microM) and time to neutropenic nadir, duration of neutropenia, platelet count nadir and grades of neuropathy or mucositis. In ten patients in whom detailed neurologic and nerve conduction studies were performed, linear regression analysis showed a significant correlation between pre- and post-HDP treatment total neuropathy scores (r2 = 0.46, P = 0.03). CONCLUSIONS: HDP (825 mg/m2 continuous infusion over 24 h) did not appear to be myeloablative. The degree of neurotoxicity subsequent to HDP was associated with the degree of baseline neuropathy but was not predictable from pharmacokinetic parameters.

Bilateral facial nerve palsy secondary to the administration of high-dose paclitaxel.

Bilateral facial nerve palsy is an uncommon occurrence. We describe a case of bilateral facial nerve palsy secondary to a single cycle of high-dose paclitaxel therapy (825 mg/m2), in a woman with breast cancer. Prior to her high-dose therapy, she had a residual grade 2 peripheral neuropathy following treatment with ten cycles of standard-dose paclitaxel (total dose 3200 mg). The features of the peripheral neuropathy due to standard-dose paclitaxel, which can be both motor and sensory, are well described. Cumulative paclitaxel dose is considered a risk factor for development of the neuropathy. Although facial nerve palsy secondary to paclitaxel is not previously reported, other cranial nerve toxicity has been described. Consistent with reports of the reversibility of paclitaxel-induced peripheral neuropathy, the facial nerve palsies in our patient resolved over 23 months. Ongoing studies of high-dose paclitaxel warrant close attention to its cumulative neurotoxic effects, particularly in patients previously treated with neurotoxic chemotherapy.

Competitive repopulation of retrovirally transduced haemopoietic stem cells.

Gene transfer into haemopoietic stem cells (HSC) may be useful in gene therapy for a variety of inherited and acquired human diseases. Cell division is required for retroviral transduction, and cytokine stimulation is often used to increase mitosis of quiescent HSC. Exposure to cytokines has been shown to have an unfavourable effect on the engraftment of these cells when competed with unmanipulated HSC. We now show that a similar engraftment defect is present when HSC are manipulated and transduced with the human multiple drug resistance (MDR) gene. The extent of the unfavourable competition depended on the relative numbers of cytokine-treated and fresh cells when the two populations of cells were administered simultaneously into marrow-ablated isogenic mice. When the manipulated transduced cells were given 2 or 4 d before the unmanipulated cells there was a much greater engraftment of the manipulated cells. The data suggested that the manipulated cells were at a relative disadvantage for marrow engraftment as compared to fresh cells, presumably due to the more efficient homing and engraftment properties of these latter unmanipulated cells. However, the manipulated cells had no intrinsic inability to engraft when they were the predominant donor cell population. In all cases the percent of MDR transduced cells in the engrafting manipulated cells remained relatively constant at about 25-30%. These results have implications for the use of manipulated transduced stem cells in gene therapy, suggesting that administering them before adding fresh cells can overcome their engraftment defect.

Wild-type p53 epitope naturally processed and presented by an HLA-B haplotype on human breast carcinoma cells.

To broaden the clinical applicability of peptide-based immunotherapy in breast cancer, there is a need to identify further tumor-associated peptide epitopes that are specific for HLA alleles, in addition to HLA-A2. The HLA-B44 haplotype is one of the most common HLA-B haplotypes, occurring in 10-20% of the population. We performed the structural characterization of HLA class I-bound self-peptides presented by a human breast cancer cell line with a HLA-A68, A32, B40, B44 haplotype, to identify potential tumor-specific antigens. Of 13 sequenced peptides, 1 peptide had the HLA-A68 peptide binding motif and 12 peptides had the HLA-B40, B44 peptide binding motif. One of the latter peptides, FEVRVCACPG, shared 100% homology to residues 270-279 of wild-type P53 protein. Our study, thus, provides direct evidence for the natural processing and presentation of p53 epitope 270-279 by HLA-B40, B44-bearing human breast tumor cells. Epitopes spanning this region of P53 may have potential use for immunotherapy in patients expressing HLA-A2 and -B44 supertypes.

Up-regulation of amphotrophic retroviral receptor expression in human peripheral blood CD34+ cells.

Retroviral-mediated gene transfer into hematopoietic stem cells provides the only means of stable transduction of these cells and their progeny for use with a variety of potentially therapeutic genes. Expression of the Moloney amphotropic retroviral receptor-pit-2 or GLVR-2-is critical to the recognition and entry of Moloney leukemia virus-derived viruses into human target cells such as CD34+ hematopoietic cells. GLVR-2 functions as a sodium-dependent phosphate transporter as well as a receptor. We have previously shown that the expression of the murine homologue of the amphotropic receptor Ram 1, also a phosphate transporter, is developmentally regulated in murine hematopoietic fetal liver cells. We also demonstrated that culture of murine fetal liver cells in phosphate-free (PO(4)-free) medium increases levels of receptor mRNA and makes murine fetal liver cells susceptible to Moloney amphotropic viral gene transfer. We now examine the effect of culture conditions on the expression of GLVR-2 in human CD34+ cells. In this report, we demonstrate that there is a 2-3 fold increase in GLVR-2 mRNA levels in CD34+ cells after 3 days in culture with interleukin 3, interleukin 6, and stem-cell factor. In addition, the use of PO(4)-free medium increases expression of GLVR-2 an additional 2-fold in these cells during this time. These results indicate that GLVR-2 expression can be up-regulated on these cells, and may permit improved retroviral gene transfer efficiencies.

A phase I study of high-dose BCNU, etoposide and escalating-dose thiotepa (BTE) with hematopoietic progenitor cell support in adults with recurrent and high-risk brain tumors.

This phase I dose-escalation study was performed to determine the tolerability of three-drug combination high-dose BCNU (B) (450 mg/m2), escalating-dose thiotepa (500-800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days in 22 adults with malignant primary brain tumors. Patients received G-CSF and hematopoeitic support with peripheral blood progenitor cells (PBPC) (n = 18) or both PBPC and marrow (n = 4). The maximum tolerated dose of thiotepa with acceptable toxicity was determined as 800 mg/m2. The 100-day mortality rate was 9% (2/22). Grade III/IV toxicities included mucositis (71%), diarrhea (29%), nausea/vomiting (19%), and hepatic toxicity (14%). Neurological toxicities occurred in 24% and included seizures (two patients) and encephalopathy (three patients). Encephalopathy was transient in two patients and progressive in one patient. All patients had neutropenic fever. Median time to engraftment with absolute neutrophil count (ANC) >0.5 x 10(9)/l was 10 days (range 8-30 days). Platelet engraftment >20 x 10(9)/l occurred after 11 days (range 9-65 days). In the eighteen patients supported solely with PBPC, there was a significant inverse correlation between CD34+ dose and days to ANC (rho = -0.78, p = 0.001) and platelet engraftment (rho = -0.76, p = 0.002). Overall, 11% of evaluable patients (2/18) had a complete response to BTE. Median time to tumor progression (TTP) was 9 months, with an overall median survival of 17 months. BCNU (450 mg/m2), thiotepa (800 mg/m2) and etoposide (1200 mg/m2) in divided doses over four days is a tolerable combination HDC regimen, the efficacy of which warrants further investigation in adults with optimally resected chemoresponsive brain tumors.

CD34+ cell dose requirements for rapid engraftment in a sequential high-dose chemotherapy regimen of paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) with PBPC support in metastatic breast cancer.

Sequential high-dose chemotherapy may increase the threshold dose of CD34+ cells necessary for rapid and successful hematologic recovery. There are limited data regarding the pharmacodynamics and threshold CD34+ cell dose required for engraftment following high-dose paclitaxel. To determine the dose of CD34+ PBPC sufficient for rapid engraftment, 65 women with metastatic breast cancer undergoing a sequential high-dose paclitaxel, melphalan, and cyclophosphamide, thiotepa, and carboplatin (CTCb) chemotherapy regimen were evaluated. The intertreatment interval was a median of 27 days. Paclitaxel was escalated from 400 to 825 mg/m2, infused continuously (CI) over 24 h on day -4 with PBPC reinfusion on day 0. Following marrow recovery, 90 mg/m2/day of melphalan was given over 30 min on days -2 and -1, with PBPC reinfusion on day 0. On recovery, patients received CTCb on days -7 to -3, with PBPC reinfusion on day 0. G-CSF was administered after each cycle until WBCC recovery. For paclitaxel, an ANC >0.5 x 10(9)/L occurred at a median of 6 days (range 0-7 days) after PBPC reinfusion. The median nadir platelet count was 63 x 10(9)/L (range 6 x 10(9)/L-176 x 10(9)/L). Eight patients (12%) had platelet nadir <20 x 10(9)/L, and all recovered their counts to >20 x 10(9)/L on day 7. There was no clinical difference in days to engraftment between women receiving <2 or > or =2 x 10(6) CD34+ PBPC/kg following paclitaxel. All patients recovered neutrophil and platelet counts within 7 days after reinfusion of > or =1 x 10(6) CD34+ cells/kg and G-CSF. The data suggest that a paclitaxel dose of 825 mg/m2 is not myeloablative. For melphalan, median days to ANC >0.5 x 10(9)/L was 10 days (range 9-15), and platelet recovery to >20 x 10(9)/L was 13 days (range 0-28) after PBPC reinfusion. Median time to engraftment was more rapid in patients receiving > or =2 x 10(6) CD34+/kg versus <2 x 10(6)CD34+/kg, for both neutrophils (11 days versus 10 days, p = 0.05) and platelets (14 days versus 12 days, p < 0.01). Ninety-eight percent of patients infused with > or =2 x 10(6) CD34+/kg engrafted within 21 days. Following CTCb in this sequential regimen, a dose of > or =2 x 10(6) CD34+ cells/kg provided for significantly more rapid neutrophil engraftment than <2 x 10(6) CD34+ cells/kg (9 days versus 10 days,p = 0.01), but a dose > or =3 X 10(6) CD34+ cells/kg is necessary for reliable, rapid, and sustained neutrophil and platelet engraftment by day 21.