Myelodysplastic syndrome after autologous peripheral blood stem cell transplantation for multiple myeloma.

Long-term survivors after autologous peripheral blood stem cell transplantation (APBSCT) for lymphoma or Hodgkin's disease are known to have a high risk of developing myelodysplastic syndrome (MDS), but the risk of MDS is not clear for patients transplanted for myeloma. We reviewed the outcomes for 82 myeloma patients who underwent APBSCT at our center. The group included 47 men and 35 women of median age 56 years (range: 37-74 years). Median time from diagnosis to APBSCT was 8.2 months (range: 2.6-86.1 months). Before coming to transplantation, 28% had received oral melphalan (MEL), 98% received other chemotherapy and 34% received radiation. A single APBSCT was provided for 68, and 32% underwent APBSCT more than once. High-dose MEL alone was used as the preparative regimen for 83%, and the remainder received at least one APBSCT with a more intensive preparative regimen. Ten patients (12%) developed MDS. The 5-year cumulative incidence is 18% (95% confidence interval, 9-30%). There were no demographic factors associated with an increased risk of developing MDS. Median survival after the diagnosis of MDS was 18 months. There is a relatively high risk of MDS after APBSCT for myeloma, and optimal therapy has not been established for these patients.

Prognostic factors for disease progression after high-dose chemotherapy and autologous hematopoietic stem cell transplantation for recurrent or refractory Hodgkin's lymphoma.

Our purpose was to study the risk factors associated with disease progression after high-dose chemotherapy followed by autologous stem cell transplantation in patients with recurrent or refractory Hodgkin's lymphoma (HL). We analyzed the long-term outcome of 184 patients with recurrent or refractory HL who underwent autologous hematopoietic stem cell transplantation. At the time of transplantation, 82 patients were in first relapse or second remission, 46 patients were refractory to the primary induction chemotherapy, and 56 patients were beyond first relapse or second remission. In 64 patients, the disease had proved refractory to the chemotherapy regimen administered immediately prior to transplantation. The median follow-up of patients who were alive and free of disease at the time of this report was 8.9 years (range, 0.1-19.0 years). At 10 years, the overall and disease-free survival rates were 34% (95% CI 27-42) and 29% (95% CI 22-36) respectively. The major cause of treatment failure was disease relapse. Chemotherapy resistance prior to transplantation, advanced stage, and higher number of chemotherapy regimens administered prior to transplantation were adverse prognostic factors for disease progression. We conclude that autologous transplantation is an effective salvage treatment for recurrent HL.

The effect of hematopoietic growth factors on the risk of graft-vs-host disease after allogeneic hematopoietic stem cell transplantation: a meta-analysis.

The effect of hematopoietic growth factors on neutrophil recovery after allogeneic transplantation is well-recognized. Recent laboratory studies demonstrated that these cytokines may also modify T-cell and dendritic cell function, but whether the effect is strong enough to alter the risk of GVHD is unclear. We performed a meta-analysis to determine the effect of G-CSF or GM-CSF on the risk of nonhematopoietic outcomes after allogeneic transplantation. A search of the literature from 1986 to present yielded 18 publications in which data were provided for cohorts receiving growth factor vs either placebo or no therapy. These included nine prospective randomized studies, eight retrospective cohort studies, and one case-control study comprising a total of 1198 patients. The publication types were heterogeneous with regard to demographic and treatment characteristics, although within publications, comparative groups were generally balanced. The pooled risk ratio estimates with use of growth factor was 1.08 (95% CI 0.87-1.33, P=0.48) for grades 2-4 acute GVHD, 1.22 (95% CI 0.80-1.86, P=0.99) for grades 3-4 acute GVHD, and 1.02 (95% CI 0.82-1.26, P=0.87) for chronic GVHD. This analysis did not detect a significant change in the risk of acute or chronic GVHD after allogeneic hematopoietic stem cell transplantation when hematopoietic growth factors were used to shorten the initial period of neutropenia.

Use of antithymocyte globulin for treatment of steroid-refractory acute graft-versus-host disease: an international practice survey.

Antithymocyte globulin (ATG) is accepted as a treatment option for steroid-refractory acute graft-versus-host disease (GVHD). We conducted an international survey to determine how steroid refractoriness is defined and how ATG is used in clinical practice. Responses were received from 153 centers in 36 countries. The most common threshold steroid dose to define steroid refractoriness was 2 mg/kg/day (67% of respondents), and the median duration of treatment before failure was declared varied from 3 to 5.5 days, depending on whether failure was defined as 'progressed', 'not improved' or 'not resolved'. The threshold corticosteroid dose was significantly higher in pediatric centers than in adult or combined programs (P = 0.003). ATG was used routinely for treatment of steroid-refractory GVHD by 67% of the respondents. Horse ATG was used more frequently than rabbit ATG overall (50% vs 24%, P < 0.001), and predominance of horse ATG was most evident in the western hemisphere, in small- to medium-sized centers, and in pediatric centers. A wide variety of dose schedules for both drugs was reported. We conclude that there is some degree of variation in the definition of steroid refractoriness, especially between pediatric and nonpediatric programs, and no consensus has emerged in identifying the optimal ATG dose schedule in this setting.

Chronic graft-versus-host disease after allogeneic blood stem cell transplantation.

The incidence, characteristics, risk factors for, and impact of chronic graft-vs-host disease (GVHD) were evaluated in a consecutive series of 116 evaluable HLA-identical blood stem cell transplant recipients. Minimum follow-up was 18 months. Limited chronic GVHD occurred in 6% (95% confidence interval [CI], 0%-13%), and clinical extensive chronic GVHD in 71% (95% CI, 61%-80%). The cumulative incidence was 57% (95% CI, 48%-66%). In univariate analyses, GVHD prophylaxis other than tacrolimus and methotrexate, prior grades 2 to 4 acute GVHD, use of corticosteroids on day 100, and total nucleated cell dose were significant risk factors for clinical extensive chronic GVHD. On multivariate analysis, GVHD prophylaxis with tacrolimus and methotrexate was associated with a reduced risk of chronic GVHD (hazard ratio [HR], 0.35; P =.001), whereas the risk was increased with prior acute GVHD (HR, 1.67; P =.046). When adjusted for disease status at the time of transplantation, high-risk chronic GVHD had an adverse impact on overall mortality (HR, 6.6; P <.001) and treatment failure (HR, 5.2; P <.001) at 18 months. It was concluded that there is a substantial rate of chronic GVHD after HLA-identical allogeneic blood stem cell transplantation, that clinical factors may alter the risk of chronic GVHD, and that high-risk chronic GVHD adversely affects outcome.

Thiotepa, busulfan, and cyclophosphamide as a preparative regimen for allogeneic transplantation for advanced myelodysplastic syndrome and acute myelogenous leukemia.

Sixty-two adults underwent marrow or blood stem cell transplantation from an HLA-matched related donor using high-dose thiotepa, busulfan, and cyclophosphamide (TBC) as the preparative regimen for treatment of advanced myelodysplastic syndrome (MDS) (refractory anemia with excess blasts with or without transformation) or acute myelogenous leukemia (AML) past first remission. All evaluable patients engrafted and had complete donor chimerism. A grade 3-4 regimen-related toxicity occurred in eight (13%) patients, and a diagnosis of MDS was the only independent risk factor for grade 3-4 regimen-related toxicity (hazard ratio 9.25, P = 0.01). Day-100 treatment-related mortality (TRM) was 19%. Poor-prognosis cytogenetics increased the risk of day-100 TRM (hazard ratio 11.4, P = 0.003), and use of tacrolimus for graft-versus-host disease prophylaxis reduced the risk of day-100 TRM (hazard ratio 0.13, P = 0.027). For all patients, the three-year relapse rate was 43% (95% CI, 28%-58%). Refractoriness to conventional induction chemotherapy prior to transplantation was an independent risk factor for relapse (hazard ratio 10.8, P = 0.02). Three-year survival was 26% (95% CI, 14%-37%); survival rates were 29% for those transplanted for AML in second remission, 31% transplanted for AML in relapse, and 17% with MDS, and there were no independent risk factors for survival. TBC is an active preparative regimen for advanced AML. Patients with advanced MDS appeared to have a higher risk of toxicity and early mortality, and alternative preparative regimens should be considered for these patients.

Characteristics of human dendritic cells generated in a microgravity analog culture system.

Generation of an effective immune response requires that antigens be processed and presented to T lymphocytes by antigen-presenting cells, the most efficient of which are dendritic cells (DC). Because of their influence on both the innate and the acquired arms of immunity, a defect in DC would be expected to result in a broad impairment of immune function, not unlike that observed in astronauts during or after space flight. In the study reported here, we investigated whether DC generation and function are altered in a culture environment that models microgravity, i.e., the rotary-cell culture system (RCCS). We observed that RCCS supported the generation of DC identified by morphology, phenotype (HLA-DR+ and lacking lineage-associated markers), and function (high allostimulatory activity). However, the yield of DC from RCCS was significantly lower than that from static cultures. RCCS-generated DC were less able to phagocytose Aspergillus fumigatus conidia and expressed a lower density of surface HLA-DR. The proportion of DC expressing CD80 was also significantly reduced in RCCS compared to static cultures. When exposed to fungal antigens, RCCS-generated DC produced lower levels of interleukin-12 and failed to upregulate some costimulatory/adhesion molecules involved in antigen presentation. These data suggest that DC generation, and some functions needed to mount an effective immune response to pathogens, may be disturbed in the microgravity environment of space.

Controlled trial of filgrastim for acceleration of neutrophil recovery after allogeneic blood stem cell transplantation from human leukocyte antigen-matched related donors.

The rapid recovery of hematopoiesis after allogeneic blood stem cell transplantation has been attributed to the quality and quantity of hematopoietic progenitors in the blood stem cell grafts from filgrastim-stimulated donors. To determine whether further stimulation with filgrastim after transplantation would affect hematopoietic recovery, a prospective, randomized, controlled study was performed. Forty-two adult recipients of allogeneic blood stem cells from human leukocyte antigen-matched related donors were randomized to receive 10 microg/kg per day filgrastim subcutaneously from day 1 through neutrophil recovery or no growth factor support after transplantation. There was no significant difference between the 2 groups in the number of CD34(+) cells infused (median, 4.8 vs 4.3 x 10(6)/kg). Graft-versus-host (GVHD) disease prophylaxis consisted of tacrolimus and steroids for 9 patients and tacrolimus and minimethotrexate for 33 patients. The group receiving filgrastim had a shorter time to neutrophil levels greater than 0.5 x 10(9)/L (day 12 vs day 15, P =.002) and to neutrophil levels greater than 1.0 x 10(9)/L (day 12 vs day 16, P =.01). The filgrastim group also had a trend for earlier discharge (day 16 vs 20, P =.05). There was no significant difference between the groups in time to platelet recovery, number of transfusions, regimen-related toxicity, infection, incidence of GVHD, relapse, survival, or hospital charges. It can be concluded that the administration of filgrastim after allogeneic blood stem cell transplantation shortens the time to neutrophil recovery. (Blood. 2001;97:3405-3410)

Preemptive control of graft-versus-host disease in a murine allogeneic transplant model using retrovirally transduced murine suicidal lymphocytes.

Suicidal lymphocytes could greatly expand the role of allogeneic transplantation by reducing graft-versus-host disease (GVHD) as a barrier to transplantation, but optimization of their use is hindered by the lack of adequate animal models. To develop an animal model that used retrovirally transduced suicidal lymphocytes in a GVHD setting, a well-characterized MHC-matched murine transplant model (B10.BR-->AKR/J) was adapted. B10.BR splenic lymphocytes stimulated with concanavalin A and interleukin 2 were infected with a retrovirus containing the low-affinity nerve growth factor receptor (LNGFR) and the HSV-TK gene and immunomagnetically selected; these LNGFR+/TK+ allogeneic lymphocytes were then cotransplanted with 1 x 10(7) bone marrow cells into lethally irradiated AKR/J recipients. The LNGFR+/TK+ donor lymphocytes persisted in the peripheral circulation for 6 months in both syngeneic and allogeneic settings. Doses of 2 x 10(6) TK+ allogeneic lymphocytes produced GVHD with a severity and time course similar to that induced by naive lymphocytes. Survival of TK+ allogeneic lymphocyte-bearing mice was significantly improved (P = 0.01) when ganciclovir (GCV; 2 mg/day) was administered on days 7-13 post transplant by i.p. injection, demonstrating that GVHD could be prevented. Fluorescence-activated cell sorting analysis demonstrated 4-fold reduction but persistent circulation of LNGFR+ lymphocytes in mice treated with GCV at various time points 1-3 months after transplantation, demonstrating selective killing of GVHD-reactive cells. We conclude that retrovirally transduced LNGFR+/TK+ murine lymphocytes can be produced, persist after transplant, remain alloreactive, and can be killed by GCV administration, resulting in reduced GVHD.

Dendritic cell-mediated stimulation of the in vitro lymphocyte response to Aspergillus.

Lymphocytes play a major role in host defense against Aspergillus, but little is known about the contribution of dendritic cells (DC) to antifungal immunity in humans. We have observed that DC derived from normal volunteers phagocytose heat-killed A. fumigatus conidia. Following 24 h of exposure to the fungus, DC displayed an increase in the mean fluorescence intensity of HLA-DR, CD80, and CD86, and an increase in the percentage of CD54(+) cells. These DC also displayed increased production of IL-12. DC derived from CD34(+) progenitors or monocytes stimulated autologous lymphocytes to proliferate and produce high levels of interferon-gamma, but not interleukin-10, in response to fungal antigen. DC generated from CD34(+) progenitors collected prior to autologous or allogeneic stem cell transplantation also partially restored the in vitro antifungal proliferative response of lymphocytes obtained from patients 1 month after transplantation. These results suggest that DC are important to host-response to A. fumigatus, and that ex vivo-generated DC might be useful in restoring or enhancing the antifungal immunity after hematopoietic stem cell transplantation.

Melphalan and purine analog-containing preparative regimens: reduced-intensity conditioning for patients with hematologic malignancies undergoing allogeneic progenitor cell transplantation.

A reduced-intensity preparative regimen consisting of melphalan and a purine analog was evaluated for allogeneic transplantation in 86 patients who had a variety of hematologic malignancies and were considered poor candidates for conventional myeloablative therapies because of age or comorbidity. Seventy-eight patients received fludarabine 25 mg/m(2) daily for 5 days in combination with melphalan 180 mg/m(2) (n = 66) or 140 mg/m(2) (n = 12). Eight patients received cladribine 12 mg/m(2) continuous infusion for 5 days with melphalan 180 mg/m(2). The median age was 52 years (range, 22-70 years). Disease status at transplantation was either first remission or first chronic phase in 7 patients, untreated first relapse or subsequent remission in 16 patients, and refractory leukemia or transformed chronic myelogenous leukemia in 63 patients. Nonrelapse mortality rates on day 100 were 37.4% for the fludarabine/melphalan combination and 87.5% for the cladribine/melphalan combination. The median percentage of donor cells at 1 month in 75 patients was 100% (range, 0%-100%). The probability of grade 2-4 and 3-4 acute graft-versus-host disease was 0.49 (95% CI, 0.38-0.60) and 0.29 (95% CI, 0.18-0.41), respectively. Disease-free survival at 1 year was 57% for patients in first remission or chronic phase and 49% for patients with untreated first relapse or in a second or later remission. On multivariate analysis the strongest predictor for disease-free survival was a good or intermediate risk category. In summary, fludarabine/melphalan combinations are feasible in older patients with associated comorbidities, and long-term disease control can be achieved with reduced-intensity conditioning in this population.

Individualizing high-dose oral busulfan: prospective dose adjustment in a pediatric population undergoing allogeneic stem cell transplantation for advanced hematologic malignancies.

We investigated whether adjusting the oral busulfan (BU) dosage on the basis of early pharmacokinetic data to achieve a targeted drug exposure could reduce transplant-related complications in children with advanced hematologic malignancies. Twenty-five children received a preparative regimen consisting of thiotepa (250 mg/m2 i.v. daily for 3 days), BU (40 mg/m2 per dose p.o. every 6 h for 12 doses), and cyclophosphamide (60 mg/kg i.v. daily for 2 days) and then underwent allogeneic stem cell transplantation. Busulfan clearance and area under concentration time-curve (AUC) were determined after the first dose using a one-compartment pharmacokinetic (PK) model with first-order absorption. The initial PK analysis was successfully completed after the first BU dose in 21 patients (84%). A final AUC of 1000-1500 microM x min/dose was targeted and subsequent doses were modified as necessary to achieve this value. Fourteen of the 25 patients (56%) required dose adjustment. Follow-up PK analysis was completed in 21 patients and 16 of these achieved the targeted BU exposure for the course of therapy. Interpatient variability in BU clearance was high (up to five-fold). The most frequent regimen-related toxicities were cutaneous and gastrointestinal (stomatitis and diarrhea). Only one patient developed hepatic veno-occlusive disease. Our study demonstrates the feasibility of adjusting the oral BU dose in individual pediatric patients. Although toxicity associated with BU seemed to be reduced, this conclusion is tempered by the fact that the overall regimen-related toxicity (RRT) remains substantial and reflected the effects of all agents used in the preparative regimen.

Tacrolimus clearance is age-dependent within the pediatric population.

For prevention of graft-versus-host disease, the consensus initial intravenous dose of tacrolimus for adults is 0.03 mg/kg/day. Whether target whole blood concentrations of tacrolimus in children undergoing hematopoietic stem cell transplantation can be achieved reproducibly with this dose is not known. We reviewed the tacrolimus blood levels and calculated clearances for 55 children (aged 6 months to 18 years, median 9 years) using tacrolimus after allogeneic marrow, blood stem cell or cord blood transplantation. The tacrolimus dose regimen was 0.03 mg/kg/day by continuous infusion starting on day -1 or day -2. At the first sampling in the peritransplant period, 71% of the tacrolimus blood levels were within the target range of 5-15 ng/ml, 87% were in the safe range of 5-20 ng/ml, 9% were toxic, and 4% were subtherapeutic. Twenty-five children were converted to oral drug using the recommended oral/intravenous dose ratio of 4.0. At the first sampling after oral conversion, 80% were in the target range, and 20% were subtherapeutic. Clearance of tacrolimus was calculated from the blood levels for patients during intravenous dosing and normalized by ideal body weight. There was a decreased clearance over the first 2 weeks only for the children >12 years old (P = 0.014). The initial calculated clearances of tacrolimus did not differ between age groups, but at steady state the mean tacrolimus clearance (+/- s.d.) was higher for those <6 years old (0.159+/-0.082 l/h/kg) than for those 6-12 years old (0.109+/-0.053 l/h/kg) or >12 years old (0.104 +/-0.068 l/h/kg). Children <6 years old undergoing hematopoietic stem cell transplantation have a higher weight-normalized tacrolimus clearance than older children and adults, and careful therapeutic monitoring is needed in the first 2 weeks after transplantation to avoid prolonged subtherapeutic dosing for this age group.

Phase 3 study comparing methotrexate and tacrolimus with methotrexate and cyclosporine for prophylaxis of acute graft-versus-host disease after marrow transplantation from unrelated donors.

After the transplantation of unmodified marrow from human leukocyte antigen-matched unrelated donors receiving cyclosporine (CSP) and methotrexate (MTX), the incidence of acute graft-versus-host disease (GVHD) is greater than 75%. Tacrolimus is a macrolide compound that, in previous preclinical and clinical studies, was effective in combination with MTX for the prevention of acute GVHD. Between March 1995 and September 1996, 180 patients were randomized in a phase 3, open-label, multicenter study to determine whether tacrolimus combined with a short course of MTX (n = 90), more than CSP and a short course of MTX (n = 90), would reduce the incidence of acute GVHD after marrow transplantation from unrelated donors. There was a significant trend toward decreased severity of acute GVHD across all grades (P =.005). Based on the Kaplan-Meier estimate, the probability of grade II-IV acute GVHD in the tacrolimus group (56%) was significantly lower than in the CSP group (74%; P =.0002). Use of glucocorticoids for the management of GVHD was significantly lower with tacrolimus than with CSP (65% vs 81%, respectively; P =. 019). The number of patients requiring dialysis in the first 100 days was similar (tacrolimus, 9; CSP, 8). Overall and relapse-free survival rates for the tacrolimus and CSP arms at 2 years was 54% versus 50% (P =.46) and 47% versus 42% (P =.58), respectively. The combination of tacrolimus and MTX after unrelated donor marrow transplantation significantly decreased the risk for acute GVHD than did the combination of CSP and MTX, with no significant increase in toxicity, infections, or leukemia relapse.

Tacrolimus does not abrogate the increased risk of acute graft-versus-host disease after unrelated-donor marrow transplantation with allelic mismatching at HLA-DRB1 and HLA-DQB1.

One hundred patients of median age 34 years (range, 14-53) received bone marrow transplants from unrelated donors serologically matched for human leukocyte antigen HLA-A, HLA-B, and HLA-DR using tacrolimus and minimethotrexate for prevention of acute graft-versus-host disease (GVHD). Sixty-eight patient-donor pairs had allelic matches at HLA-DRB1 and HLA-DQB1, 20 pairs had a single mismatch at HLA-DRB1 or HLA-DQB1, and 12 were mismatched at both HLA-DRB1 and HLA-DQB1. Minimum follow-up time was 6 months. Grades 2 to 4 GVHD occurred in 43% of patients with matched donors, 69% with single allele-mismatched donors, and 71% with double allele-mismatched donors; grades 3 to 4 GVHD occurred in 22%, 43%, and 64%, respectively. On multivariate analysis, the relative risk of grades 2 to 4 GVHD was 2.2 (95% CI, 1.1-4.5; P = .03) with a single allele mismatch and 2.7 (95% CI, 1.2-6.0; P = .02) with a double allele mismatch. The relative risks of grades 3 to 4 GVHD were 3.0 (95% CI, 1.2-7.6; P = .02) and 5.0 (95% CI, 1.9-12.6; P = .001), respectively. Day 100 treatment-related mortality was also adversely affected by allelic mismatching, occurring in 21% of those with matched donors, 50% with single allele-mismatched donors, and 42% with double allele-mismatched donors (P = .02), but overall survival at day 180 did not differ significantly among the 3 groups. Tacrolimus does not abrogate the adverse impact of allele mismatching at HLA-DRB1 and HLA-DQB1 on the risk of moderate-to-severe acute GVHD.

Daclizumab, a humanized anti-interleukin-2 receptor alpha chain antibody, for treatment of acute graft-versus-host disease.

Daclizumab, a humanized monoclonal IgG1 directed against the alpha chain of the interleukin-2 receptor (IL-2R), is a competitive inhibitor of IL-2 on activated lymphocytes. To test the hypothesis that specific inhibition of activated lymphocytes in patients with ongoing acute graft-versus-host disease (GVHD) might ameliorate the process, we treated 43 patients with advanced or steroid-refractory GVHD with daclizumab. The first cohort of 24 patients was treated with daclizumab 1 mg/kg on days 1, 8, 15, 22, and 29. On day 43, the complete response (CR) rate was 29% (95% confidence interval [CI], 13%-51%). Survival on day 120 was 29% (95% CI, 13%-51%). A second cohort of 19 patients was treated with daclizumab 1 mg/kg on days 1, 4, 8, 15, and 22. For these patients, the CR rate on day 43 was 47% (95% CI, 24%-71%), and survival on day 120 was 53% (95% CI, 29%-76%). There were no infusion-related reactions and no serious side effects related to daclizumab. Following treatment, there was a reduction in serum concentrations of soluble IL-2R and peripheral blood CD3( + )25(+) lymphocytes, but these changes were not predictive of response. Daclizumab has substantial activity for the treatment of acute GVHD, and the second regimen evaluated is recommended for a controlled study. (Blood, 2000; 95:83-89)

High CD34 cell doses do not worsen regimen-related toxicity or early mortality after autologous blood stem cell transplantation for breast cancer.

BACKGROUND: Some transplant-related complications, such as the engraftment syndrome, are thought to be mediated by cytokines released during expansion of hematopoietic progenitors at the time of neutrophil recovery. Since there is an inverse correlation between CD34(+) cell dose and time to neutrophil recovery, we sought to determine if peritransplant toxicity and early mortality were adversely affected by high CD34(+) cell doses. METHODS: The study group included 186 women with breast cancer who received high-dose cyclophosphamide, carmustine, thiotepa and an autologous PBSC transplant. The median CD34(+) cell dose was 5.9 x 10(6)/kg (1.0-154.7 x 10(6)/kg). Patients were categorized by CD34(+) cell dose (1.0-3.5, 3.6-5.9, 6.0-19.9, and 20.0-154.7 x 10(6)/kg) for assessment of outcomes. RESULTS: Grades 2-4 mucositis occurred in 49%, cardiac toxicity in 7%, pulmonary toxicity in 5%, cystitis in 4%, diarrhea in 3%, renal toxicity in 1%, and central nervous system toxicity in 1%. A Grade 2-4 regimen-related toxicity occurred in 109 patients (59%) and Grade 3-4 in eight patients (4%). Overall survival was 100% at Day 30, 96% at Day 90, and 89% at 1 year. Treatment-related mortality was 3.8%. In multivariate analyses that included prior chemotherapy, disease status, visceral metastases, prior chest radiation and age, CD34(+) cell dose group was not an independent risk factor for Grade 2-4 mucositis, Grade 2-4 maximum toxicity, Grade > or =3 cumulative toxicity, 90 day survival or 1 year survival. DISCUSSION: We conclude that CD34(+) cell doses >20 x 10(6)/kg do not affect transplant outcome in a negative or positive fashion.

Clinical trials of HER-2/neu-specific vaccines.

Recently there has been a renewed interest in developing vaccines for use in cancer treatment. Part of this interest stems from a better understanding of the immune system, the identification of a number of T-cell-specific tumor antigens, more effective adjuvants, and the ability to construct more immunogenic molecules using recombinant DNA techniques. Studies from several laboratories have shown that breast cancer patients have preexisting immunity to the HER-2/neu oncoprotein receptor (HER-2) in the form of elevated antibody titers and T-cell immunity. Preclinical studies showed enhanced delayed-type hypersensitivity and cytotoxic T-lymphocyte precursors in spleens from animals immunized with several human leukocyte antigen class I and class II peptides derived from the HER-2 protein. Phase I trials of these peptides combined with the cytokine granulocyte-macrophage colony-stimulating factor as a part of therapy in patients with HER-2-positive cancers have shown minimal local toxicity, along with enhanced helper T-cell activity and antibody production in patients with minimal disease. Increases in cytotoxic T-lymphocyte precursor activity were less frequent, but in some cases could be enhanced when patient lymphocytes were incubated ex vivo with the proinflammatory cytokine interleukin-12. Other preclinical studies designed to enhance HER-2 peptide immunogenicity are in progress. Additional current and future clinical trials using HER-2-derived vaccines will be discussed.