An MDS-specific frailty index based on cumulative deficits adds independent prognostic information to clinical prognostic scoring

The frailty index (FI) is based on the principle that the more deficits an individual has, the greater their risk of adverse outcomes. It is expressed as a ratio of the number of deficits present to the total number of deficits considered. We developed an MDS-specific FI using a prospective MDS registry and assessed its ability to add prognostic power to conventional prognostic scores in MDS. The 42 deficits included in this FI included measurements of physical performance, comorbidities, laboratory values, instrumental activities of daily living, quality of life and performance status. Of 644 patients, 440 were eligible for FI calculation. The median FI score was 0.25 (range 0.05-0.67), correlated with age and IPSS/IPSS-R risk scores and discriminated overall survival. With a follow-up of 20 months, survival was 27 months (95% CI 24-30.4). By multivariate analysis, age >70, FI, transfusion dependence, and IPSS were significant covariates associated with OS. The incremental discrimination improvement of the frailty index was 37%. We derived a prognostic score with five risk groups and distinct survivals ranging from 7.4 months to not yet reached. If externally validated, the MDS-FI could be used as a tool to refine the risk stratification of current clinical prognostication models.

Overexpression of Arginase 1 is linked to DNMT3A and TET2 mutations in lower-grade myelodysplastic syndromes and chronic myelomonocytic leukemia

Immune dysregulation is a common feature of myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML), particularly in early stages. However, the genetic basis remains poorly understood. We recently reported that macrophages from mice deficient in tet methylcytosine dioxygenase 2 (Tet2), a model of MDS/CMML, are hyperinflammatory and have increased expression of arginase 1 (Arg1). In macrophages and myeloid derived suppressor cells (MDSCs) expression of Arg1 contributes to T-cell suppression and immune evasion by L-arginine depletion, in the setting of chronic inflammation and cancer. Since human MDS and CMML are driven by TET2 mutations and associated with chronic inflammation, we hypothesized that arginase enzymatic activity and ARG1 expression would be increased in human MDS/CMML bone marrow. Elevated arginase activity was observed in bone marrow mononuclear cells of MDS and CMML patients with lower-grade features. Immunohistochemical studies confirmed that myelomonocytic cells overexpress ARG1. Additionally, mutations in the epigenetic regulators TET2 and DNMT3A corresponded to high ARG1 expression and activity. These findings suggest ARG1 is a biomarker of immune dysregulation in early MDS and CMML. Recent murine findings have implicated Tet2 and Dnmt3a in regulation of innate immunity. Our study suggests similar changes may be driven by human TET2 and DNMT3A mutations.

Granulocyte colony-stimulating factor in secondary prophylaxis for advanced-stage Hodgkin lymphoma treated with ABVD chemotherapy: a cost-effectiveness analysis

Granulocyte colony-stimulating factor (G-CSF) is commonly administered to patients with Hodgkin lymphoma (HL) with neutropenia. We constructed a decision-analytic model to compare the cost-effectiveness of secondary prophylaxis with G-CSF to a strategy of 'no G-CSF' in response to severe neutropenia for adults with advanced-stage HL treated with ABVD. A Canadian public health payer's perspective was considered and costs were presented in 2013 Canadian dollars. The quality-adjusted life years (QALYs) attained with the G-CSF and 'no G-CSF' strategies were 1.403 and 1.416, respectively. Costs for the strategies with and without G-CSF were $38,971 and $33,982, respectively. In the base case analysis, the 'no G-CSF' strategy was associated with cost savings and improved QALYs; therefore, 'no G-CSF' was the dominant approach. For patients with severe neutropenia during ABVD chemotherapy for advanced-stage HL, a strategy without G-CSF support is associated with improved quality-adjusted outcomes, cost savings, and is the preferred approach.

Monthly blood transfusions decrease after four months of azacitidine

BACKGROUND AND OBJECTIVES

Azacitidine (AZA) improves overall survival and transfusion independence in patients with myelodysplastic syndrome (MDS). We aimed to quantify the reduction in red blood cell (RBC) transfusions and to determine when this reduction occurs, in MDS patients treated with AZA.

MATERIALS AND METHODS

We performed a retrospective audit of changes in RBC transfusion burden in 51 patients with predominantly higher risk MDS (26.5% high risk, 51.0% intermediate-2) who received AZA. Transfusion requirements were audited 6 months prior to and up to 18 months after therapy initiation, and data were analysed using a generalized linear mixed model.

RESULTS

At baseline, 30 patients (58.8%) were transfusion dependent (TD). Seventeen patients (56.7%) achieved transfusion independence (TI) by 18 months, and 8 of these patients (47.1%) achieved this response by 4 months on therapy. Achievement of TI was not consistently durable in these 17 patients, as 11 patients reverted to TD while on therapy. Meanwhile, 6 of 21 patients who were TI at baseline became TD on therapy. The monthly average of RBC units transfused decreased significantly beginning at 4 months, with a reduction from 2.50 units per month at baseline to 1.00 units per month at month 4. This 60% reduction was significant (P = 0.002) and sustained beyond 12 months.

CONCLUSION

These results bolster the notion that AZA significantly reduces transfusion burden and resource utilization and illustrate the limitations of the current WHO erythroid response criteria which do not account for differing durability and fluctuations of response.

Do quality of life or physical function at diagnosis predict short-term outcomes during intensive chemotherapy in AML?

BACKGROUND

Intensive chemotherapy (IC) used to treat acute myeloid leukemia (AML) is associated with toxicity, particularly in older adults. Emerging data suggest that baseline quality of life (QOL) and physical function may predict outcomes in oncology, although data in AML are limited. We investigated the association between baseline QOL and physical function with short-term treatment outcomes in adults and elderly AML patients.

MATERIALS AND METHODS

We conducted a prospective, longitudinal study of adults (age 18+) AML patients undergoing IC. Before starting IC, patients completed the European Organisation for the Research and Treatment of Cancer (EORTC) 30-item questionnaire (QLQ-C30) and Functional Assessment of Cancer Therapy Fatigue subscale (FACT-Fatigue) in addition to physical function tests (grip strength, timed chair stands, 2-min walk test). Outcomes included 60-day mortality, intensive care unit (ICU) admission and achievement of complete remission (CR). Logistic regression was carried out to evaluate each outcome.

RESULTS

Of the 239 patients (median age 57.5 years), 56.7% were male and median Charlson comorbidity score was 0. Sixty-day mortality, ICU admission and CR occurred in 9 (3.7%), 15 (6.3%) and 167 (69.9%) patients, respectively. Using univariate regression, neither QOL nor physical function at presentation was predictive of 60-day mortality (all P > 0.05), whereas ICU admission (P < 0.001) and remission status at 30 days (P = 0.007) were. Fatigue (P = 0.004) and role functioning (P = 0.003) were predictors of ICU admission; QOL and physical function were not. A higher Charlson score predicted ICU admission (P = 0.01) and remission status (P = 0.002). The cytogenetic risk group was associated with achievement of CR (P = 0.02); QOL and physical function were not (all P > 0.05). Findings were similar when patients age 60+ were examined. Relationships between fatigue and role functioning with ICU admission deserve further exploration.

CONCLUSIONS

Baseline QOL and physical function tests in this prospective study were not associated with short-term mortality, ICU admission or achievement of CR after the first cycle of chemotherapy.

Cost-effectiveness in Canada of azacitidine for the treatment of higher-risk myelodysplastic syndromes

OBJECTIVE

Our goal was to determine the economic value of azacitidine in Canada compared with conventional care regimens (ccrs), including best supportive care (bsc) and low- or standard-dose chemotherapy plus bsc in the treatment of higher-risk myelodysplastic syndromes (mdss) and acute myeloid leukemia (aml) with 20%-30% blasts.

METHODS

The cost-utility model is a lifetime probabilistic Markov model with a 35-day cycle length consisting of 3 health states: mds; transformation to aml with more than 30% blasts; and death. A third-party public payer perspective was adopted. Overall survival was extrapolated beyond the time horizon of the aza-001 trial comparing azacitidine with ccr. Resource use was determined through a questionnaire completed by Canadian hematologists. Utility values were obtained from two studies in which EQ-5D health questionnaire values were mapped from the European Organization for Research and Treatment of Cancer qlq-C30 survey, and SF-6D scores were mapped from the Short Form 12, elicited from 191 and 43 patients in two different trials.

RESULTS

In the base case, azacitidine had an incremental cost-effectiveness ratio (icer) of $86,182 (95% confidence limits: $69,920, $107,157) per quality-adjusted life year (qaly) gained relative to ccr. Comparing azacitidine with bsc, low-dose chemotherapy plus bsc, and standard-dose chemotherapy plus bsc, the icers were, respectively, $86,973, $84,829, and $2,152 per qaly gained. Results were most sensitive to the utility for azacitidine after 6 months of treatment and to overall survival.

CONCLUSIONS

The prolonged 9-month median overall survival with azacitidine relative to ccr fills a gap w hen treating patients with higher-risk mds and aml with 20%-30% blasts. The economic value of azacitidine is within the threshold of willingness-to-pay for third-party public payers for oncology treatments in Canada.

An international phase II trial of single-agent lenalidomide for relapsed or refractory aggressive B-cell non-Hodgkin's lymphoma

BACKGROUND

Lenalidomide is an immunomodulatory agent with antitumor activity in B-cell malignancies. This phase II trial aimed to demonstrate the safety and efficacy of lenalidomide in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), follicular grade 3 lymphoma (FL-III), or transformed lymphoma (TL).

METHODS

Patients received oral lenalidomide 25 mg on days 1-21 every 28 days as tolerated or until progression. The primary end point was overall response rate (ORR).

RESULTS

Two hundred and seventeen patients enrolled and received lenalidomide. The ORR was 35% (77/217), with 13% (29/217) complete remission (CR), 22% (48/217) partial remission, and 21% (45/217) with stable disease. The ORR for DLBCL was 28% (30/108), 42% (24/57) for MCL, 42% (8/19) for FL-III, and 45% (15/33) for TL. Median progression-free survival for all 217 patients was 3.7 months [95% confidence interval (CI) 2.7-5.1]. For 77 responders, the median response duration lasted 10.6 months (95% CI 7.0-NR). Median response duration was not reached in 29 patients who achieved a CR and in responding patients with FL-III or MCL. The most common adverse event was myelosuppression with grade 4 neutropenia and thrombocytopenia in 17% and 6%, respectively.

CONCLUSION

Lenalidomide is well tolerated and produces durable responses in patients with relapsed or refractory aggressive non-Hodgkin's lymphoma.

Efficacy and safety of lenalidomide oral monotherapy in patients with relapsed or refractory diffuse large B-cell lymphoma: Results from an international study (NHL-003)

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Background: Patients with diffuse large-B-cell lymphoma (DLBCL) who are not cured with R-CHOP or high-dose chemotherapy with autologous stem cell rescue have a dismal prognosis. A recent phase II trial (NHL-002) of lenalidomide in patients with relapsed or refractory aggressive non-Hodgkin's lymphoma (NHL) demonstrated a 19% overall response rate (ORR) with a 7-month median duration of response (DR) in the subset of patients with DLBCL. A supporting international phase II trial (NHL-003) of single-agent lenalidomide was initiated for patients with relapsed or refractory aggressive NHL that had received at least one prior treatment and had measurable disease. Herein, we report the data from the DLBCL patients enrolled in this trial. Methods: Patients received 25 mg oral lenalidomide once daily on days 1–21 of every 28-day cycle and continued therapy until disease progression or toxicity. The 1999 IWLRC methodology was used to assess response and progression. Results: One hundred-three DLBCL patients were enrolled and were evaluable for response assessment. The median age was 66 years (21–87) and 70 patients (68%) were male. Median time from diagnosis was 2 years (0.4–18.6), patients had received a median of 3 prior treatment regimens (1–10) and 46 of the patients (45%) had received a prior stem cell transplant (DLBCL-stem cell). Response rates are shown in the Table . Grade 3 or 4 adverse events occurring in more than 5% of patients were neutropenia (34%), thrombocytopenia (18%), asthenia (9%), anemia (8%), leucopenia (7%), back pain (6%) and dyspnea (6%). Conclusions: This international study demonstrates that lenalidomide is active in heavily pre-treated patients with relapsed or refractory DLBCL and has manageable side effects.

[Table: see text]

[Table: see text]

Efficacy and safety of lenalidomide oral monotherapy in patients with relapsed or refractory mantle-cell lymphoma: Results from an international study (NHL-003)

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Introduction: Relapsed or refractory MCL patients demonstrated a promising overall response rate (ORR) of 53% with a median duration of response (DR) of 13.7 months to single-agent lenalidomide when analyzed as a subset in a recent a phase II study (NHL-002). A supporting international phase II trial (NHL-003) of single-agent lenalidomide was initiated for patients with relapsed or refractory aggressive NHL. In this report, we analyze the current results from the MCL patients enrolled in this trial. Methods: Patients with relapsed or refractory MCL and measurable disease 2 cm after at least 1 prior treatment regimen were eligible. Patients received 25 mg of lenalidomide orally once daily on days 1–21 of every 28-day cycle. Patients continued therapy until disease progression or toxicity. The 1999 IWLRC methodology was used to assess response and progression. Results: Fifty-four MCL patients were enrolled and were evaluable for response assessment. Median age was 69 years (33–82) and 40 patients (74%) were male. Median time from diagnosis was 3.2 years (0.4–10.4), patients had received a median of 3 prior treatments (1–8), 17 of the patients (32%) had received prior bortezomib therapy (MCL-bortezomib), and 14 (26%) had received a prior stem cell transplant (MCL-stem cell). Response rates are shown in the Table. The most common grade 3 or 4 adverse events were neutropenia (43%), thrombocytopenia (22%) and anemia (11%). Conclusions: This is the second study to demonstrate that lenalidomide oral monotherapy is effective in the treatment of patients with relapsed or refractory MCL, with manageable side effects.

[Table: see text]

[Table: see text]

Phase II testing of sunitinib: the National Cancer Institute of Canada Clinical Trials Group IND Program Trials IND.182-185

Sunitinib (SU11248) is an orally bioavailable inhibitor that affects the receptor tyrosine kinases involved in tumour proliferation and angiogenesis, including vascular endothelial growth factor (VEGF) receptors 1, 2, 3, and platelet-derived growth factor receptors alpha (PDGFRA) and beta (PDGFRB). Because angiogenesis is necessary for the growth and metastasis of solid tumours, and VEGF is believed to have a pivotal role in that process, SUNITINIB treatment may have broad-spectrum clinical utility. In the present article, we discuss the biologic and clinical rationales that have recently led the Investigational New Drug Program of the National Cancer Institute of Canada Clinical Trials Group to initiate four phase ii trials testing this agent in the following four different tumour types: relapsed diffuse large cell lymphoma, malignant pleural mesothelioma, locally advanced or metastatic cervical cancer and recurrent epithelial ovarian, fallopian tube, or primary peritoneal carcinoma.

Intensive chemotherapy and autologous stem-cell transplantation plus rituximab is superior to conventional chemotherapy for newly diagnosed advanced stage mantle-cell lymphoma: a matched pair analysis

BACKGROUND

The outcome of 20 patients with newly diagnosed mantle-cell lymphoma (MCL) treated on a prospective trial of autologous stem-cell transplantation (ASCT) and rituximab immunotherapy was compared with the outcome of 40 matched historical control patients treated with standard combination chemotherapy.

PATIENTS AND METHODS

Control patients with MCL were identified from a lymphoma database, and pairs were matched with patients receiving ASCT-rituximab for stage of disease, gender and age (+/-5 years). Only patients treated with an anthracycline- or cyclophosphamide-fludarabine-based regimen were included.

RESULTS

Seventeen of 20 patients who received ASCT-rituximab remain alive in remission at a median of 30 months from diagnosis; one patient relapsed 2 years post-ASCT, and two died at 7 and 11 months post-ASCT without evidence of lymphoma. Of 40 patients treated with conventional chemotherapy, with a median follow-up of 80 months, 33 have relapsed or progressed and 29 have died. Overall (OS) and progression-free (PFS) survival were superior in patients treated with ASCT-rituximab compared with those treated with conventional chemotherapy (PFS at 3 years, 89% versus 29%, P <0.00001; OS at 3 years, 88% versus 65%, P = 0.052).

CONCLUSIONS

This matched-pair analysis suggests that patients with advanced-stage MCL treated with ASCT-rituximab had statistically significantly better PFS and a trend toward better OS than patients treated with conventional chemotherapy. Longer follow-up will determine response duration and the true impact of this treatment strategy on PFS and OS.

Follow-up of patients with Hodgkin's disease following curative treatment: the routine CT scan is of little value

A total of 10-40% of patients with Hodgkin's disease relapse following initial curative therapy. Intensive follow-up is resource intensive and may identify false relapses. We performed a retrospective review of all patients with Hodgkin's disease treated at our centre between 1990 and 1999 to evaluate the utility of the components of follow-up. A total of 107 patients met the inclusion and exclusion criteria. The median age was 33 years and the median duration of follow-up 38 months. The total number of follow-up visits was 1209 and total number of CT scans 283. There were 109 suspected relapses of which 22 proved to be true relapses. Of the latter, 14 were identified clinically, six radiologically and two via lab testing. The routine CT scan detected only two relapses (9%), yet accounted for 29% of the total follow-up costs. Based on data from our centre, the cost per true relapse was $6000 US, 49% incurred by radiological tests. The majority of the cost of follow-up was incurred by routine follow-up (84%) as opposed to the investigation of suspected relapses (16%). We conclude that most true relapses are clinically symptomatic and that the routine CT is an expensive and inefficient mode of routine follow-up.

Pharmacokinetic study of patients with follicular or mantle cell lymphoma treated with rituximab as 'in vivo purge' and consolidative immunotherapy following autologous stem cell transplantation

BACKGROUND

Little is known about the pharmacokinetics of rituximab in an autologous stem cell transplant (ASCT) setting.

PATIENTS AND METHODS

We evaluated serum rituximab levels in 26 patients with follicular or mantle cell lymphoma treated with a combination of ASCT and immunotherapy. Patients received nine infusions of rituximab (375 mg/m(2)): one dose as an 'in vivo purge' prior to stem cell collection, and two 4-week cycles at 8 and 24 weeks following ASCT. Pre- and post-infusion serum rituximab levels were measured during the purging dose, with doses 1 and 4 of both sets of maintenance rituximab cycles, and 12 weeks and 24 weeks following treatment.

RESULTS

Rituximab levels were detectable after the first infusion, and peaked at a mean concentration of 463.8 micro g/ml after the final dose. Levels remained detectable 24 weeks after completion of treatment. There was a trend toward higher rituximab levels in patients with follicular lymphoma. Serum concentrations achieved during the maintenance cycles were similar to levels observed in patients with measurable lymphoma treated during 'the pivotal trial'. No correlation was observed between serum rituximab levels achieved in the minimal disease state and the risk of later clinical relapse, nor with the ability to achieve a molecular remission following ASCT.

CONCLUSIONS

The finding that patients treated in minimal disease states and at the time of active disease both achieve similar final serum rituximab concentrations after four infusions suggests that the pharmacokinetics are complex, and may not necessarily correlate with disease burden. The precise factors influencing rituximab clearance in patients with lymphoma are unresolved, and this remains an area of active research.

The development of marked elevation in white blood cell count does not predict inferior outcome in chronic lymphocytic leukemia

Although elevation of the white blood cell (WBC) count at diagnosis of chronic lymphocytic leukemia (CLL) appears to predict shortened survival, its significance later in the course of the disease remains unclear. We reviewed all cases of CLL seen in our center between 1980 and 1999 to evaluate the frequency and clinical significance of WBC elevation > 100 x 10(9)/L. CLL was confirmed according to standard diagnostic criteria and data was collected from diagnosis, occurrence of WBC > 100 x 10(9)/L, and last follow-up. 235 consecutive patients with CLL were identified; 94 were excluded. 141 included patients had a median age of 61 years and median WBC 19.7 x 10(9)/L at diagnosis. Median follow-up for all patients was 56 months, and median survival was 104 months. 41 patients (29%) had > or = 1 episode of WBC > 100 x 10(9)1/L, occurring at a median of 38 months from diagnosis. Compared to controls matched for modified Rai stage, development of a WBC > 100 x 10(9)/L did not predict inferior survival (median 107 vs. 101 months, p = 0.72). We conclude that the occurrence of a WBC count > 100 x 10(9)/L in patients with CLL does not shorten the survival, and patients require therapy only if other indications for treatment are present.

Bcl-2 clearance: optimising outcomes in follicular non-Hodgkin's lymphoma

The long median survival time of patients with follicular non-Hodgkin's lymphoma (NHL), means that the efficacy of new treatments are difficult to assess in the short term. Bcl-2 is an inhibitor of apoptosis and overexpression of the bcl-2 gene in the blood or bone marrow is a feature in up to 85% of patients with follicular NHL. Levels of bcl-2(+) cells in the peripheral blood or bone marrow therefore are a useful measure of disease status in such patients and can be detected by polymerase chain reaction (PCR). Complete bcl-2 clearance from the bone marrow (molecular remission) following autologous stem cell transplant (ASCT) for follicular NHL is considered to be an important prognostic factor for disease-free survival. Tumour cell contamination of the stem cell grafts used in ASCT is commonly associated with relapse. This can be addressed by purging the stem cell harvest prior to transplantation. Various methods of in vitro purging after stem cell collection have been shown to reduce the level of contamination but yield is invariably reduced and grafts remain bcl-2 positive. However, in vivo purging with rituximab during the process of collection has been used to obtain bcl-2-negative stem cell harvests without compromising the yield. Rituximab is a monoclonal antibody licensed for treatment of relapsed and refractory low-grade or follicular NHL. Rituximab targets the CD20 antigen, which is found on cells of the B cell lineage. When used for in vivo purging it depletes the peripheral blood of CD20-positive cells and prevents contamination by lymphoma cells. Molecular remission, as measured by bone-marrow bcl-2 clearance, has been achieved in 7/7 patients with follicular NHL at 1 year after treatment with ASCT using rituximab as an 'in vivopurse', followed by rituximab maintenance. Early clinical outcomes are also encouraging.

ALVAC-mediated gene transfer is efficient in lymphoid malignancies of T-and early B-cell origin, but not in tumors arising from mature B-cells

Natural attenuation of ALVAC virus in mammals makes it an attractive vector for cancer vaccine therapy of immunocompromised hosts, such as patients with lymphoid malignancies. However, the transduction efficiency of ALVAC constructs in lymphoid tumors has not yet been characterized. We studied a wide spectrum of human T- and B-cell leukemia and lymphomas and found significant heterogeneity of the ALVAC-mediated gene product expression in these tumors. While ALVAC-B7.1, ALVAC-B7.2, or ALVAC-luciferase vectors effectively expressed recombinant genes in malignancies arising from T- or early B-cell precursors, negative or low expression of ALVAC recombinant genes occurred in tumors arising from mature B-cells. We showed that ALVAC-encoded B7.1 or B7.2 was continuously expressed on the infected, and subsequently irradiated, leukemia cells, and only cells with ALVAC-mediated expression of costimulatory molecules (but not unmodified leukemia cells or those infected with the ALVAC-parental vector) induced significant proliferation and IFN-gamma production by alloreactive T-cells. These data provide the rationale for clinical studies using the ALVAC vector system for gene transfer into lymphoid tumors of T- and early B-cell origin to render them more immunogenic, while alternative strategies should be considered for immunotherapy of mature B-cell malignancies.

Outpatient supportive care following chemotherapy for acute myeloblastic leukemia

Treatment of acute myeloid leukemia (AML) involves aggressive myelosuppressive chemotherapy that is generally administered on an inpatient basis. In our centre, AML therapy has been initiated in hospital and followed by early outpatient supportive care according to guidelines established in 1996. We conducted a review of all patients presenting with AML in our centre between January 1996 and July 1998 to evaluate the safety and feasibility of early outpatient supportive care. Nineteen consecutive patients treated with induction chemotherapy were analyzed. Patients were treated with cytosine arabinoside and an anthracycline as aggressive AML induction therapy with the intent for early discharge. Ten patients (53%) were discharged within 10 days of starting induction chemotherapy (median 4.5 days). Reasons for remaining in hospital included sepsis, serious medical complications, and social and geographic factors. Patients discharged early had a median of 1.5 readmissions (range 0-3), but had 30% fewer in-hospital days than inpatients (p = 0.03), and 57% fewer days of in-hospital antibiotic therapy (p = 0.01). There were no significant differences in transfusion requirements or episodes of febrile neutropenia between the two groups. Thirty-one cycles of consolidation therapy were administered to the 18 patients who survived induction. Early discharge from hospital was achieved for 30 cycles (97%). Nine cycles of consolidation chemotherapy were delivered using outpatient intravenous infusion pumps (29%). This study supports the feasibility and safety of early discharge and outpatient supportive care following chemotherapy for AML.

Shiga-like toxin-1 receptor on human breast cancer, lymphoma, and myeloma and absence from CD34(+) hematopoietic stem cells: implications for ex vivo tumor purging and autologous stem cell transplantation

The ribosome-inactivating protein, Shiga-like toxin-1 (SLT-1), targets cells that express the glycolipid globotriaosylceramide (CD77) on their surface. CD77 and/or SLT-1 binding was detected by flow cytometry and immunocytochemistry on lymphoma and breast cancer cells recovered from biopsies of primary human cancers as well as on B cells or plasma cells present in blood/bone marrow samples of multiple myeloma patients. Breast cancer cell lines also expressed receptors for the toxin and were sensitive to SLT-1. Treatment of primary B lymphoma, B-cell chronic lymphocytic leukemia, and myeloma B or plasma cells with SLT-1-depleted malignant B cells by 3- to 28-fold, as measured by flow cytometry. Depletion of myeloma plasma cells was confirmed using a cellular limiting dilution assay followed by reverse transcriptase-polymerase chain reaction analysis of clonotypic IgH transcripts, which showed a greater than 3 log reduction in clonotypic myeloma cells after SLT-1 treatment. Receptors for the toxin were not detected on human CD34(+) hematopoietic progenitor cells (HPC). HPC were pretreated with a concentration of SLT-1 known to purge primary malignant B cells and cultured for 6 days. The number of HPC was comparable in toxin-treated and untreated cultures. HPC were functionally intact as well. Colony-forming units (CFU) were present at an identical frequency in untreated and SLT-1 pretreated cultures, confirming that CFU escape SLT-1 toxicity. The results suggest the ex vivo use of SLT-1 in purging SLT-1 receptor-expressing malignant cells from autologous stem cell grafts of breast cancer, lymphoma, and myeloma patients.

Stem cell function and engraftment is not affected by "in vivo purging" with rituximab for autologous stem cell treatment for patients with low-grade non-Hodgkin's lymphoma

The chimeric anti-CD20 monoclonal antibody rituximab (Rituxan; IDEC Pharmaceuticals, San Diego, CA, and Genentech, Inc, San Francisco, CA) has recently been approved by the US Food and Drug Administration as single-agent treatment of relapsed/refractory low-grade or follicular non-Hodgkin's lymphoma. Initial results from the pivotal clinical trial revealed that response rates to rituximab were higher in patients who previously had high-dose therapy and autologous stem cell transplantation. We have initiated a clinical trial that combines the use of rituximab with high-dose chemotherapy followed by autologous stem cell transplantation for patients with chemosensitive relapsed follicular small cleaved or mantle cell lymphoma. A unique feature of this study is that in addition to eight maintenance infusions of rituximab after autologous stem cell transplantation, patients also received rituximab 375 mg/m2 2 days before a granulocyte colony-stimulating factor-mobilized stem cell collection as "in vivo purge." We report on preliminary results demonstrating the safety and efficacy of the in vivo purge on 10 patients undergoing stem cell mobilization, nine of whom have already undergone transplantation. The peripheral blood CD34+ counts were 14.92 and 20 x 10(6)/L on day 4 and day 5, respectively, of the stem cell mobilization with granulocyte colony-stimulating factor. This compares with 11.7 and 11.8 x 10(6)/L, respectively, for the control population. The median CD34 stem cell yield in the graft collection was 3.7 x 10(6)/kg in patients receiving rituximab in vivo purge compared with 3.1 x 10(6)/kg in the control population. The target stem cell collection was successfully collected in six of 10 patients in a 1-day single large-volume leukapheresis collection, while two patients required 2 days and the last two patients required 3 days. Functional assays revealed the stem cell colony-forming unit-granulocyte monocyte and burst-forming unit-erythrocyte to be 55 and 44 colonies per plate, respectively, for the patients receiving the in vivo rituximab purge. This compares favorably with 37 and 38.5 colonies per plate, respectively, for the control population. Neutrophil engraftment took a median of 11 days for both cohorts; platelet independence was achieved in 8 days compared with 10 days for the control population. The median number of platelet transfusions was two for patients receiving rituximab and 2.5 for the control group. Assessment of serum cytokines immediately before the rituximab infusion during the stem cell mobilization and immediately after revealed a twofold to sevenfold increase in interleukin-1beta, tumor necrosis factor-alpha, and interleukin-6. The polymerase chain reaction analysis for minimal residual disease in stem cell collections and in peripheral blood and bone marrow samples of these patients will help to determine the efficacy of rituximab in vivo purge on disease progression.