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

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

Docetaxel effectively mobilizes peripheral blood CD34+ cells

We prospectively evaluated docetaxel (100 mg/m2) with G-CSF (10 microg/kg S.C., daily) for mobilization efficiency in 26 patients with breast cancer. The minimum target yield was >4.5 x 10(6) CD34+ cells/kg (optimum = 9 x 10(6)/kg), sufficient to support the subsequent three cycles of high-dose therapy (HDT). The peak days for peripheral blood (PB) CD34+ cells were day 8 and day 9. Seven collections began on day 7, 16 on day 8 and three on day 9. The median peripheral blood progenitor cell (PBPC) CD34+ cell content ranged from 1.2 to 5.9 x 10(6)/kg per day during days 7 to 11 with a median CD34+ content of the total 72 PBPC collections of 3.4 x 10(6)/kg (0.07-15.6). Fifteen patients obtained a PBPC collection exceeding 5 x 10(6)/kg on a single day of collection. Following a median 3 days collection for each patient (range 2-4), the median total CD34+ for all individual sets of collections was 9.7 x 10(6)/kg (range 1.0-28.4). We were able to achieve the minimum CD34+ cell target yield in 22 of 26 patients with one cycle of mobilisation chemotherapy and in two of these patients a second collection yielded sufficient cells. Twenty-two patients have subsequently received repetitive HDT and PBPC transplantation with 57 cycles of HDT having been delivered. For all 57 cycles, the median time to absolute neutrophil count (ANC) >0.5 x 10(9)/l and 1.0 x 10(9)/l was 10 days (range 8-22) and 11 days (range 8-23), respectively. The median time to platelets greater than 20 x 10(9)/l, 50 x 10(9)/l and 100 x 10(9)/l was 13 days (range 11-23), 17 days (range 12-53) and 23 days (range 18-70), respectively. We conclude that docetaxel with G-CSF effectively mobilises PBPCs with apheresis needing to be commenced approximately 8 days after docetaxel administration.

Serological diagnosis of idiopathic pulmonary alveolar proteinosis

Previously, we reported the specific occurrence of neutralizing autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF) in the bronchoalveolar lavage fluid from 11 Japanese patients with idiopathic pulmonary alveolar proteinosis (I-PAP). The autoantibody was also detected in sera from all 5 I-PAP patients examined. To determine that the existence of the autoantibody is not limited to the Japanese patients, we examined sera from 24 I-PAP patients in five countries and showed that the autoantibody was consistently and specifically present in such patients. Thus, detection of the autoantibody in sera can be used for diagnosis of I-PAP. To establish a simple and convenient method for diagnosis of I-PAP, we developed a novel latex agglutination test using latex beads coupled with recombinant human GM-CSF. GM-CSF binding proteins isolated from the sera using the latex beads were identified as the autoantibodies of IgG(1) and IgG(2). The titer of the autoantibody determined by this test correlated with that determined by ELISA. Agglutination was positive in 300-fold diluted sera from all 24 I-PAP patients, but negative in sera from four secondary PAP patients, two congenital PAP patients, 40 patients with other lung diseases, and 38 of 40 normal subjects. These results establish that the latex agglutination test is a reliable method for serological diagnosis of I-PAP with high sensitivity (100%) and specificity (98%).

Deafness from eighth cranial nerve involvement in a patient with large-cell transformation of mycosis fungoides

Central nervous system (CNS) involvement by mycosis fungoides (MF) is rare and is usually seen in advanced stages with lymph node or visceral involvement. We describe a patient with advanced stage MF in large-cell transformation who presented with profound hearing loss after chemotherapy. Despite an initial differential diagnosis of vincristine-related neurotoxicity based on clinical, audiometric, and MRI investigations, CSF examination revealed lymphomatous leptomeningeal involvement. This case illustrates the importance of an awareness of the possibility of CNS involvement by MF and underlines the need for a complete neurologic evaluation including CSF examination in a patient with underlying MF who presents with a new neurological problem.

Sequential cis-platinum and fludarabine with or without arabinosyl cytosine in patients failing prior fludarabine therapy for chronic lymphocytic leukemia: a phase II study

Patients with chronic lymphocytic leukemia (CLL) who fail fludarabine (Fluda) therapy have a poor response to subsequent salvage regimens and a poor prognosis. This study was undertaken to determine the efficacy and toxicity of a cis-platinum, (cis-p)fluda and arabinosyl cytosine (ara-C) combination in patients who were refractory to fluda or had relapsed following prior fluda therapy for CLL. Forty-one patients who had progressive CLL were treated on study. Eleven patients (27%) were sensitive to fluda and thirty (73%) refractory prior to study entry. Therapy consisted of cis-p 100 mg/m2 continuous intravenous (i.v.) infusion over 4 days, fluda 30 mg/m2 i.v. over 15 minutes on Days 3 and 4 either given alone (PF) or with ara-C 500 mg/m2 i.v. over 1 hour on Day 4 (PFA). The median number of PF or PFA courses received was two. No patient achieved a complete response. Eight patients (19%) achieved a partial response (PR), 28 were taken off study with progressive or refractory disease and 5 had induction deaths. The overall median survival was 6 months, 15 months in responding patients, and 4 months in non-responding patients. Rai stage I-II patients had a median survival of 7 months and stage III-IV patients had a median survival of 3 months. Major toxicities (myelosuppression, sepsis, renal failure and tumor lysis syndrome) were frequent. In conclusion, it can be said that the PF and PFA regimens have equivalent modest activity in patients with progressive CLL following prior fluda therapy, predominantly among patients whose disease was sensitive to fluda at last prior exposure. Ara-C did not add to the activity of the cis-p/fluda combination in this study group.

Secondary acute myeloid leukemia with inv(16): report of two cases following paclitaxel-containing chemotherapy and review of the role of intensified ara-C therapy

Acute myeloid leukemia developing secondary to prior cytotoxic chemotherapy (s-AML) encompasses a range of distinct entities. We report two cases of s-AML with inv(16)(p13q22) who had prior exposure to paclitaxel. Additionally, two previously reported cases of s-AML with inv(16) had prior paclitaxel exposure raising the possibility that the taxanes may predispose to this specific syndrome of s-AML. One of our patients received escalated-dose ara-C chemotherapy, achieving a complete remission (12+ months). We therefore examined the prognosis of previously reported cases of s-AML with inv(16) and analyzed the influence of escalated-dose ara-C (>/=400 mg/m2/day). A total of 25 evaluable cases were identified, with 96% attaining CR independent of ara-C dose. The estimated median remission duration was 40 months and the median survival has not been reached (actuarial 5-year survival 52 +/- 18%). Although not achieving statistical significance, patients treated with escalated dose ara-C (n = 15) had longer remission duration and overall survival than those treated with standard dose ara-C (n = 10) (P = 0.063 and 0.20, respectively). In univariate analysis, younger age, male gender, and the presence of additional cytogenetic abnormalities were associated with a tendency towards adverse outcomes (P< 0.1). Age and gender were equally distributed between ara-C dose cohorts, but more patients treated with standard-dose ara-C had additional cytogenetic abnormalities (P = 0.048). Within the limitations of this retrospective study, this analysis suggests that, similar to de novo AML with inv(16), secondary cases may also potentially benefit from treatment with escalated-dose ara-C. This is consistent with the premise that the underlying molecular defect, rather than the presence of prior cytotoxic drug exposure, may be the most important determinant of disease behavior and chemotherapy responsiveness in AML.

Mini-allografts' for haematological malignancies: an alternative to conventional myeloablative marrow transplantation

BACKGROUND

Considerable morbidity and mortality are consequences of the myeloablative chemoradiotherapy utilised in conventional allogeneic marrow transplantation. This has generally restricted such potentially curative treatment to patients <50-55 years with normal organ function. Recent studies suggest that purine-analogue based non-myeloablative regimens are sufficiently immunosuppressive to facilitate allogeneic donor cell engraftment.

AIM

To review the outcome of HLA-compatible sibling allogeneic peripheral blood progenitor cell (PBPC) transplants using fludarabine-based conditioning in patients ineligible for a conventional transplant, with emphasis on engraftment, graft vs host disease (GVHD) and graft vs tumour effects.

METHODS

Eleven patients (nine > or = 47 years age) with advanced haematological malignancies received one of three different fludarabine-based chemotherapy followed by infusion of granulocyte colony-stimulating factor mobilised PBPC. Cyclosporin-methotrexate was used as GVHD prophylaxis.

RESULTS

Two patients died early; minimal non-haematological toxicity apart from mucositis occurred in the other nine. Eight of the nine evaluable patients had evidence of durable donor cell engraftment in preference to recipient cells. Acute GVHD (> or = grade 2) occurred in seven of eight patients with donor engraftment who survived beyond two months. Four patients are alive in complete remission 8-28 months post-transplant; another is alive in probable remission at four months.

CONCLUSIONS

Fludarabine-based non myeloablative chemotherapy facilitates rapid engraftment of allogeneic donor cells, which produce powerful GVHD and graft vs tumour effects. This approach has the potential to extend the applicability of allogeneic stem cell transplants to patients traditionally regarded as too old or sick for conventional marrow transplants.

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

BACKGROUND

This phase I study was designed to determine the optimal dosages of a novel repetitive high-dose therapy regimen for patients with metastatic breast cancer (MBC).

PATIENTS AND METHODS

The planned treatment was three cycles of high-dose ifosfamide, thiotepa and conventional-dose paclitaxel delivered every 28 days with progressive dose-escalation in successive cohorts. Each cycle was supported by peripheral blood progenitor cells (PBPC) and filgrastim.

RESULTS

Twenty-three patients were entered into this trial. Of the planned 69 treatment cycles, 59 were delivered and fifteen patients completed all three cycles. The dose-limiting toxicities were renal tubular acidosis, encephalopathy, mucositis and enterocolitis. There was one treatment-related hemorrhagic death.

CONCLUSIONS

The recommended doses for phase II or III studies are ifosfamide (10 g/m2), thiotepa (350 mg/m2) and paclitaxel (175 mg/m2).

Fludarabine-based non-myeloablative chemotherapy followed by infusion of HLA-identical stem cells for relapsed leukaemia and lymphoma

Many patients have not been offered potentially curative allogeneic marrow transplants because of the toxicity of myeloablative regimens in the setting of advanced age or organ dysfunction. We treated five patients, ineligible for myeloablative chemotherapy due to one of these criteria, with fludarabine-based non-myeloablative chemotherapy followed by reinfusion of G-CSF-mobilised allogeneic peripheral blood progenitor cells (PBPC). Two patients died early of multi-organ failure. Another patient with massive splenomegaly was infused with a suboptimal number of PBPC; no engraftment was documented. The remaining two patients demonstrated mixed chimerism early post-transplant, but by 3 and 6 months respectively, engraftment was almost entirely of donor origin. One of these patients, transplanted with relapsed AML, remains in remission with extensive chronic GVHD at 17 months. The other patient, transplanted with chemorefractory mantle cell lymphoma, progressed early post-transplant but entered remission coincident with the onset of severe GVHD following cessation of cyclosporin A, suggesting a powerful graft-versus-mantle cell lymphoma effect. These preliminary observations suggest this approach results in engraftment and GVHD/graft-versus-tumour effects similar to myeloablative regimens and may provide an alternative in patients ineligible for conventional conditioning regimens.

Attenuated hematopoietic response to granulocyte-macrophage colony-stimulating factor in patients with acquired pulmonary alveolar proteinosis

The pathogenesis of acquired pulmonary alveolar proteinosis (PAP), a rare lung disease characterized by excessive surfactant accumulation within the alveolar space, remains obscure. Gene-targeted mice lacking the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) or the signal-transducing beta-common chain of the GM-CSF receptor have impaired surfactant clearance and pulmonary pathology resembling human PAP. We therefore investigated the hematopoietic effects of GM-CSF in patients with PAP. The hematologic response of 5 infants with congenital PAP to 5 microgram/kg/d was of normal magnitude. By contrast, despite normal expression of GM-CSF receptor alpha- and beta-common chains on peripheral blood myelomonocytic cells (n = 6) and normal binding affinity of bone marrow mononuclear cells for GM-CSF (n = 3), each of the 12 patients with acquired PAP treated displayed impaired responses to GM-CSF; 5 microgram/kg/d produced only minor eosinophilia, and doses of 7.5 to 20 microgram/kg were required to induce >/=1.5-fold neutrophil increments in the 3 patients who underwent dose-escalation. However, neutrophilic responses to 5 microgram/kg granulocyte colony-stimulating factor (G-CSF) were normal (n = 4). In vitro, the proportion of hematopoietic progenitors responsive to GM-CSF (16.1% +/- 8.9%; P = .042) or interleukin-3 (IL-3; 19.3% +/- 7.7%; P = .063), both of which utilize the beta-common chain of the GM-CSF receptor complex, were reduced among patients with acquired PAP (n = 4) compared with normal bone marrow donor controls (47.2% +/- 25.9% and 40.9% +/- 18.6%, respectively). In the one individual who had complete resolution of lung disease during the period of study, this was temporally associated with correction of this defective in vitro response to GM-CSF and IL-3 on serial assessment. These data establish that patients with acquired PAP have an associated impaired responsiveness to GM-CSF that is potentially pathogenic in the development of their lung disease. Based on these observations, we propose a model of the pathogenesis of acquired PAP that suggests the disease arises as a consequence of an acquired clonal disorder within the hematopoietic progenitor cell compartment.

Progress in management of acute myeloid leukaemia (AML) in Australia since 1980: a single institution retrospective study

BACKGROUND

Much research has been conducted into the pathobiology, diagnosis, and management of acute myeloid leukaemia (AML) since 1980, with major contributions from Australian studies in this period.

AIMS

To determine whether advances in basic and clinical research into AML have translated into improved survival for patients in the community.

METHODS

A retrospective survey of records of all patients with AML presenting to the Royal Melbourne Hospital (RMH) over a 16 year period, analysed according to induction therapy and established prognostic factors. Between 1980 and December 1996 223 (98%) of 227 patients were evaluable.

RESULTS

The probability of survival at five years for patients treated since 1990 has improved significantly compared to the cohort treated between 1980-89 (34 +/- 5% vs 4 +/- 2%; mean +/- standard error). This benefit is most evident in patients less than 60 years of age (50 +/- 7% vs 11 +/- 4%). Successive induction protocols in the context of clinical trials conducted since 1985 contributed to improved outcomes. The selective application of bone marrow transplantation, and use of retinoic acid as induction therapy for acute promyelocytic leukaemia has also improved survival. Despite increases in dose-intensity, early death rates for patients undergoing induction therapy fell during the study period.

CONCLUSIONS

Participation in clinical and basic research with the development of more intense and specific treatments for patients with AML has contributed to better outcomes, underpinned by improvements in supportive care.

Mice lacking both granulocyte colony-stimulating factor (CSF) and granulocyte-macrophage CSF have impaired reproductive capacity, perturbed neonatal granulopoiesis, lung disease, amyloidosis, and reduced long-term survival

Mice lacking granulocyte colony-stimulating factor (G-CSF) are neutropenic with reduced hematopoietic progenitors in the bone marrow and spleen, whereas those lacking granulocyte-macrophage colony-stimulating factor (GM-CSF) have impaired pulmonary homeostasis and increased splenic hematopoietic progenitors, but unimpaired steady-state hematopoiesis. These contrasting phenotypes establish unique roles for these factors in vivo, but do not exclude the existence of additional redundant functions. To investigate this issue, we generated animals lacking both G-CSF and GM-CSF. In the process of characterizing the phenotype of these animals, we further analyzed G-CSF- and GM-CSF-deficient mice, expanding the recognized spectrum of defects in both. G-CSF-deficient animals have a marked predisposition to spontaneous infections, a reduced long-term survival, and a high incidence of reactive type AA amyloidosis. GM-CSF-deficient mice have a modest impairment of reproductive capacity, a propensity to develop lung and soft-tissue infections, and a similarly reduced survival as in G-CSF-deficient animals. The phenotype of mice lacking both G-CSF and GM-CSF was additive to the features of the constituent genotypes, with three novel additional features: a greater degree of neutropenia among newborn mice than in those lacking G-CSF alone, an increased neonatal mortality rate, and a dominant influence of the lack of G-CSF on splenic hematopoiesis resulting in significantly reduced numbers of splenic progenitors. In contrast to newborn animals, adult mice lacking both G-CSF and GM-CSF exhibited similar neutrophil levels as G-CSF-deficient animals. These findings demonstrate that the additional lack of GM-CSF in G-CSF-deficient animals further impairs steady-state granulopoiesis in vivo selectively during the early postnatal period, expand the recognized roles of both G-CSF and GM-CSF in vivo, and emphasize the utility of studying multiply deficient mouse strains in the investigation of functional redundancy.

Role of splenectomy in chronic lymphocytic leukemia

BACKGROUND

The benefit of splenectomy, performed for complications of chronic lymphocytic leukemia (CLL) including autoimmune hemolytic anemia, thrombocytopenia, hypersplenism, and symptomatic splenomegaly, has not been clearly demonstrated. The objective of this study was to determine if splenectomy achieves a predictable hematologic and survival advantage over conventional chemotherapy in patients with CLL.

STUDY DESIGN

A retrospective review was performed of 77 consecutive patients with CLL who underwent splenectomy between 1970 and 1994 at the University of Texas M. D. Anderson Cancer Center. Indications for splenectomy, pre- and postoperative hematologic profiles, response to splenectomy, and time to progression and death were recorded. Kaplan-Meier life tables were constructed, and a comparison to an age- and gender-matched cohort of CLL patients treated with fludarabine and no splenectomy was performed using log rank statistical analysis.

RESULTS

Seventy-six percent of the patients studied were Rai stage III/IV. Twenty of 29 patients with hemoglobin counts (Hb) < or = 10 g/dL and 11 of 18 patients with platelet counts (plt) < 50 x 10(9)/L achieved an excellent hematologic response to splenectomy. Splenectomy significantly improved survival in patients with Hb < or = 10 g/dL or plt < or = 50 x 10(9)/L (p = 0.025). Thrombocytopenia did not significantly increase postoperative morbidity, and mortality rate was not significantly different between treatment groups.

CONCLUSIONS

Splenectomy significantly improves survival in selected subgroups of patients with advanced-stage CLL over that achieved with conventional chemotherapy. Based on these results, splenectomy should be performed early in the course of the disease in CLL patients with either an Hb < or = 10 g/dL or plt < or = 50 x 10(9)/L.

Prognostic value of serum interleukin-6 in diffuse large-cell lymphoma

BACKGROUND

Interleukin-6 has important lymphoid bioregulatory effects, and serum levels of interleukin-6 are often elevated in patients with lymphoma.

OBJECTIVE

To determine the relation between serum levels of interleukin-6 before treatment and outcome in patients with diffuse large-cell lymphoma.

DESIGN

Retrospective cohort analysis with multivariate analysis.

SETTING

Tertiary referral center.

PARTICIPANTS

118 untreated patients with diffuse large-cell lymphoma who were enrolled in frontline chemotherapy protocols and 45 healthy controls.

MEASUREMENTS

Serum levels of interleukin-6 were measured by using a sensitive enzyme-linked immunosorbent assay. Levels below the upper limit of the range for controls were considered normal. Outcomes were complete response, failure-free survival, and overall survival.

RESULTS

Serum levels of interleukin-6 were higher in patients with lymphoma (median, 4.6 pg/ml [range, undetectable to 224 pg/mL]) than in controls (median, undetectable [range, undetectable to 4.3 pg/mL]) (P = 0.009). The complete response rate was 95% for persons with normal interleukin-6 levels and 55% for persons with high interleukin-6 levels (P = 0.001). Patients with high interleukin-6 levels had inferior failure-free and overall survival rates (P < 0.001 for both comparisons). The actuarial 4-year failure-free and overall survival rates were 72% and 85%, respectively, for persons with normal interleukin-6 levels and 37% and 46%, respectively, for persons with high interleukin-6 levels. In multivariate analysis, interleukin-6 was selected as the most significant predictor of complete response and failure-free survival. Failure-free and overall survival of patients stratified according to International Prognostic Index score could be further stratified by interleukin-6 level (P < or = 0.03 for all comparisons).

CONCLUSION

In patients with diffuse large-cell lymphoma, serum interleukin-6 levels are an independent prognostic factor for complete response and failure-free survival.

Bilateral fracture of the mandible in chronic lymphocytic leukaemia. Case report

The development of osteolytic bone lesions in patients with chronic lymphocytic leukaemia (CLL) is extremely rare and has not been reported to involve the mandible. A case of bilateral pathologic fracture of the mandible extensively involved with multiple bony deposits of CLL is reported.

Clinical correlates of elevated serum levels of interleukin 6 in patients with untreated Hodgkin's disease

BACKGROUND

Interleukin-6 (IL-6) is a potent immunomodulatory cytokine that may have pathogenetic significance in several malignancies. In addition, high IL-6 levels have been associated with a poor prognosis in multiple myeloma, nonHodgkin's lymphoma, ovarian cancer, and renal cancer, as well in advanced Hodgkin's lymphoma. In this study, we analyzed IL-6 levels in newly diagnosed Hodgkin's disease and determined clinical correlates of elevated levels.

PATIENTS AND METHODS

Using a sensitive enzyme-linked immunosorbent assay (lower limit of sensitivity = 0.35 pg/mL) we measured IL-6 levels in sera from 33 healthy controls and 65 untreated patients with Hodgkin's disease.

RESULTS

Interleukin-6 levels in the Hodgkin's patients (median 2.7 pg/mL; range < 0.35 to 38.4 pg/mL) were significantly higher than in the controls (median < 0.35 pg/mL; range < 0.35 to 1.87 pg/mL; P < 0.0001). Interleukin-6 levels were also higher in males (P = 0.03) and in patients with bulky disease (P = 0.026) or advanced Ann Arbor stage (P = 0.017). In addition, serum levels of IL-6 also showed direct linear correlations with the erythrocyte sedimentation rate (r = 0.64, P = 0.0007), platelet count (r = 0.53, P < 0.0001), leukocyte count (r = 0.36, P = 0.003), and beta (2)-microglobulin level (r = 0.4, P = 0.0012); and an inverse linear correlation with serum albumin level (r = -0.43, P = 0.0003). In the 10 patients tested who had elevated serum IL-6 levels pretherapy and who achieved complete remission, serum IL-6 values decreased at the time of remission to the range found in healthy controls.

CONCLUSIONS

Our observations suggest that, in patients with Hodgkin's disease, serum levels of IL-6 are frequently elevated at diagnosis, normalize during remission, and are associated with specific disease characteristics including several adverse prognostic features.

Case/control study of the role of splenectomy in chronic lymphocytic leukemia

PURPOSE

This retrospective analysis was performed to evaluate critically the morbidity and mortality of splenectomy in patients with chronic lymphocytic leukemia and to determine the probability of hematologic response. Further, using a case/control format based on multivariate analysis-derived predictors of survival, we evaluated the influence of splenectomy on survival.

PATIENTS AND METHODS

Between 1971 and 1993, 55 patients with chronic lymphocytic leukemia underwent splenectomy. They were compared with 55 fludarabine-treated patients who had been matched for age, serum albumin level, sex, hemoglobin level, Rai stage, number of prior therapies, and time from diagnosis.

RESULTS

In the perioperative period, blood-product usage was modest, and common morbidities were limited to minor infections in 18% of the patients and pneumonia/atelectasis in 25%. Perioperative mortality was 9%. Deaths were related to septic complications in all cases and associated with a preoperative performance status > or = 2 (P = .05). The only predictor identified for hemoglobin and neutrophil increments was spleen weight (P < .05). No factors predictive of platelet increment were identified. The early death rate (within 30 days) and overall survival of splenectomy and control patients were not significantly different (P > .2). Among Rai stage IV patients, those who were splenectomized displayed a strong trend for improved overall survival (P = .15 by log-rank test). The 2-year actuarial survival rate of Rai stage IV patients was 51% +/- 9% in the splenectomy group and 28% +/- 9% in the control group.

CONCLUSION

Splenectomy can be performed with modest morbidity, mortality, and resource utilization in patients with advanced chronic lymphocytic leukemia and significant cytopenias. The procedure results in major hematologic benefits in most patients, with hemoglobin and neutrophil increments correlated with spleen weight. Overall, the survival of splenectomized patients is equivalent to control patients. Thrombocytopenic patients (< 100 x 10(9)/L) are most likely to obtain hematologic benefit, and potentially enjoy improved survival. These patients would be suitable for a randomized study to establish definitively the role of splenectomy in chronic lymphocytic leukemia.

Response duration and recovery of CD4+ lymphocytes following deoxycoformycin in interferon-alpha-resistant hairy cell leukemia: 7-year follow-up

The long-term outcome of patients with hairy cell leukemia resistant to interferon-alpha (IFN-alpha) following treatment with deoxycoformycin (DCF) was examined, and the kinetics of recovery of lymphocyte subsets and factors influencing the rate of recovery investigated. Between May 1986 and May 1989, 15 patients with histologically confirmed hairy cell leukemia resistant to IFN-alpha received DCF 4 mg/m2 every 2 weeks with 12 cycles planned. All 15 patients were evaluable for response and have been followed for a median of 88 months (range, 72 to 106 months) from the start of therapy. Fourteen patients responded to DCF, all attaining complete remission (CR) (response rate 93%; 95% confidence interval, 69% to 100%). Seven patients have developed recurrent disease after 45 to 74 months. Using the method of Kaplan and Meier, the median remission duration is 74 months and, at 8 years, 46% (95% confidence interval, 33% to 59%) of patients are projected to be in ongoing CR. The seven relapsing patients have responded to treatment with 2-chlorodeoxyadenosine (2-CdA) and all 15 patients remain alive. After DCF, nadir CD4+ and CD8+ lymphocyte counts were significantly lower than prior to therapy (P < 0.0001 and P = 0.05, respectively), but returned to baseline levels during follow-up. Median times to attainment of the lower limit of the normal range of CD4+ and CD8+ lymphocytes were 54 and 36 months, respectively. Those patients who had previously undergone splenectomy (n=7) had higher baseline CD4+ (P= 0.073) and CD8+ (P= 0.043) lymphocyte counts and more rapid recovery of both CD4+ (P= 0.027) and CD8+ lymphocyte counts (P = 0.016) than non-splenectomized patients. One elderly patient (age, 78 years) was diagnosed with subsequent malignancy. No late opportunistic infections were observed. Resistance to IFN-alpha does not impair subsequent responsiveness of patients with hairy cell leukemia to treatment with DCF. Responses are durable and without evidence of long-term sequelae. CD4+ and CD8+ lymphocyte subsets recover slowly without clinical manifestations of immunodeficiency. Splenectomized patients appear to have higher baseline lymphocyte counts and more rapid lymphocyte recovery following treatment with DCF.

Parathyroid hormone-related protein in hypercalcaemia associated with haematological malignancy

The incidence of hypercalcaemia and its association with humoral mechanisms involving parathyroid hormone-related protein (PTHrP), parathyroid hormone (PTH), or 1.25(OH)2 vitamin D were assessed in a prospective study of patients admitted to a clinical haematology unit. Hypercalcaemia was detected in 18/165 patients, and was due to primary hyperparathyroidism in 3/17 patients in whom results of humoral mediator assessments were obtained. In the other patients, hypercalcaemia was associated in nine instances with myeloma, in five with B-cell non-Hodgkin's lymphoma (NHL), and in one with myeloid neoplasia. No evidence was obtained of a humoral mechanism involving 1.25(OH)2 vitamin D, but elevated circulating levels of PTHrP, comparable with those in humoral hypercalcaemia of malignancy, were present in 2/4 patients with NHL, and in 3/9 with myeloma. The relationship between presence or absence of elevated circulating PTHrP, and presence or absence of hypercalcaemia during the course of treatment, indicated PTHrP was involved in the production of hypercalcaemia. Such an association raises the possibility that PTHrP released by neoplastic cells in these disorders acts in a paracrine manner to produce local bone resorption, and when produced in greater amounts causes elevated circulating levels which make an additional humorally-mediated contribution to the development of hypercalcaemia.

Influence of fludarabine on pharmacokinetics and pharmacodynamics of cytarabine: implications for a continuous infusion schedule

Arabinosylcytosine (ara-C) is a cytotoxic agent with major activity against acute leukemias. To exert this effect, it must first be phosphorylated to its active 5'-triphosphate, ara-CTP, which is incorporated into DNA. Our previous studies demonstrated that preincubation with arabinosyl-2-fluoroadenine (F-ara-A) increased the rate of ara-CTP accumulation in leukemia cells when incubated with 10 microM ara-C. Such concentrations of ara-C are readily obtained during intermittent bolus infusions of ara-C, and clinical trials were conducted using fludarabine in combination with 2-h infusions of intermediate-dose ara-C. During continuous infusion of ara-C, however, serum ara-C levels are <10 microM. Because the effectiveness of ara-C depends on the levels of intracellular ara-CTP and its incorporation into DNA, we sought to investigate the influence of fludarabine on pharmacodynamics of ara-C at concentrations of ara-C achieved during continuous infusion. Using the K562 human leukemic cell line, we established that incubation with 30 microM F-ara-A was able to modulate intracellular dNTP pools and achieve maximum enhancement of ara-CTP levels at all concentrations of ara-C tested (0.3-10.0 microM). The relative enhancement of ara-CTP concentrations ranged from 2.2- to 2.8-fold. Combination of F-ara-A with 1.0 and 3.0 microM ara-C also increased the incorporation of ara-CTP into DNA. To model the influence of F-ara-A on continuous infusion ara-C, cells were incubated with 1 microM ara-C alone or in combination with F-ara-A. The F-ara-A-incubated cells accumulated effective intracellular concentrations of F-ara-ATP, which resulted in greatly increased intracellular ara-CTP levels. These studies demonstrate the capacity of clinically attainable concentrations of F-ara-ATP to enhance the formation of ara-CTP at concentrations of ara-C that are achieved during a continuous infusion schedule. Given the important role intracellular ara-CTP concentrations and ara-CMP incorporation into DNA have on the ultimate cytotoxic capacity of ara-C against acute myelogenous leukemia blasts, these studies suggest a promising pharmacological model for improving the efficacy of the continuous infusion ara-C regimen.

High rate of prolonged remissions following combined modality therapy for patients with localized low-grade lymphoma

PURPOSE

Involved field (IF) radiation can cure as many as 40% to 50% of patients with stage I-II low-grade lymphoma. We sought to improve these results by prospectively evaluating the combination of IF radiation and chemotherapy consisting of 10 courses of cyclophosphamide, vincristine, prednisone, and bleomycin, with doxorubicin added in a risk-adapted manner (COP/CHOP-Bleo).

PATIENTS AND METHODS

From 1984 until December 1992, 91 patients, median age 56 years (range 28 to 77 years), with clinical stage I-II low-grade lymphoma were treated. No patients were excluded on the basis of age or organ function.

RESULTS

A complete response was attained in 99% of evaluable patients. Treatment-related toxicity was mild, and no deaths occurred during therapy. With a median follow-up of 60 months, there have been only 16 relapses. The actuarial freedom from relapse rate at five years is 82% (95% confidence interval 71% to 89%) and at 10 years is 73%. At five years the overall survival rate is 90% (95% confidence interval 81% to 95%) and at ten years it is 82%. Of the clinical features examined, only older age (> 56 years; p = 0.07) was associated with shorter survival. No features examined were predictive of disease relapse.

CONCLUSION

The combination of IF radiation and risk-adapted COP/CHOP-Bleo chemotherapy is well-tolerated, produces a very high rate of complete remission, and with a median follow-up of five years, has produced lower rates of relapse and better overall survival than has been reported for IF radiation alone in patients with clinically-staged I-II low-grade lymphoma.

Survival of young patients with chronic lymphocytic leukemia failing fludarabine therapy: a basis for the use of myeloablative therapies

We examined the survival of 91 young patients (< or = 55 years) with chronic lymphocytic leukemia from the time of failure of fludarabine therapy, in an attempt to identify those with a poor outcome who may benefit from investigative dose-intensive therapies. The median survival of patients unresponsive to fludarabine (n = 42) was 48 weeks, and only 11% responded to subsequent therapies. The median survival of patients relapsing following a fludarabine-induced remission (n = 49) was 87 weeks, and 83% of those who had received fludarabine as their first therapy (n = 14) responded to further fludarabine-containing therapies, with 60% alive at four years. Only 7% of those relapsing patients who had received fludarabine as salvage therapy (n = 35) responded to subsequent therapies (median survival 72 weeks). The poor outlook for these patients justifies the consideration of innovative dose-intensive therapies, such as bone marrow transplantation, with their attendant risk of toxicity.

Response to interferon-alpha in patients with hairy cell leukemia relapsing after treatment with 2-chlorodeoxyadenosine

2-Chlorodeoxyadenosine (2-CdA) has recently established itself as an extremely effective therapy for patients with hairy cell leukemia. To date, the issue of how to treat patients relapsing after 2-CdA has not been adequately addressed. In our initial study, 41 of 46 patients achieved an objective response (complete or partial remission). The only persistent toxicity associated with this agent appears to be significant suppression of CD4+ lymphocyte counts, albeit without evidence of clinical sequelae at a median follow-up of 30 months (range, 7-43). Eight patients have developed recurrent disease 3-23 months (median, 16 months) after 2-CdA. Because of progressive cytopenias, three of these patients were treated with interferon-alpha (IFN-alpha) (3 x 10(6) units subcutaneously three times per week), commencing 2, 9 and 16 months after the documentation of relapse. All three patients have shown an objective response with reduction of marrow hairy cells and amelioration of neutropenia and thrombocytopenia (two patients, complete remission; one patient, partial remission). Responses were maintained while on IFN-alpha, but two patients relapsed shortly (3 and 4 months, respectively) after discontinuation of IFN. There was no significant toxicity. Prior to commencing IFN-alpha, 22-36 months after 2-CdA, these patients' absolute CD4+ counts were suppressed (mean 211/microliters, s.d. +/- 85/microliters), but have not significantly changed after 10, 11 and 18 months of IFN-alpha therapy (mean 225/microliters, s.d. +/- 93/microliters). These results suggest that in hairy cell leukemia patients relapsing after 2-CdA, IFN-alpha may be a reasonable therapeutic option, especially if persistent CD4+ lymphocytopenia is present.

Serum levels of interleukin-10 in patients with diffuse large cell lymphoma: lack of correlation with prognosis

Interleukin-10 (IL-10), also known as cytokine synthesis inhibitory factor, has multiple effects on lymphoid development. In addition, it has been previously reported that serum levels of IL-10 correlate with failure-free and overall survival in patients with non-Hodgkin's lymphoma. In this study, we used a sensitive enzyme-linked immunosorbent assay specific for human IL-10 (lower limit of sensitivity, 5 pg/mL) to measure serum levels in 52 newly diagnosed patients with diffuse large cell lymphoma and at least one adverse prognostic feature who were subsequently treated in a uniform way. Lymphoma patients had significantly higher serum levels of IL-10 (median, 7.98 pg/mL; range, < or = 5 to 27,143 pg/mL) than healthy volunteers (N = 50; median, < or = 5 pg/mL; range, < or = 5 to 19.21 pg/mL) (P = .0000012). Individuals with B symptoms had significantly higher serum levels of IL-10 than those without them (P = .03), but there was no correlation between IL-10 levels and any of the other prognostic variables analyzed, including age, lactic dehydrogenase, beta 2-microglobulin levels, performance status, bulky disease, Ann Arbor stage, or International Index score. More importantly, we found no correlation between IL-10 levels and the achievement of complete remission, nor with failure-free survival or overall survival. We conclude that in a uniform population of untreated patients with diffuse large cell lymphoma, serum levels of IL-10 do not appear to have any prognostic value.

The contribution of Auer rods to the classification and prognosis of myelodysplastic syndromes

Auer rods were first recognized at the beginning of this century. Their presence soon became considered to be an unequivocal manifestation of a leukemic process. Possibly influenced by this long-held assumption, in 1982 the French-American-British co-operative group (FAB) incorporated the presence of Auer rods into a classification system of the myelodysplastic syndromes that remains in widespread clinical usage today. Although unsubstantiated at the time, the presence of Auer rods was suggested to indicate a rapidly progressive disorder and a poor prognosis. In the absence of studies confirming the utility of Auer rods as a diagnostic criterion, the FAB classification system of myelodysplastic syndromes has been widely used to allocate therapy. In this review we examine the early descriptions of Auer rods and critically evaluate the studies examining the value their presence has in the classification and prognosis of patients with myelodysplastic syndromes.

Serum interleukin-6 levels correlate with prognosis in diffuse large-cell lymphoma

PURPOSE

Interleukin-6 (IL-6) is a potent immunomodulatory cytokine that may have pathogenetic and prognostic significance in a number of disorders. The objective of this study was to examine the correlation between serum IL-6 levels and phenotypic characteristics, as well as outcome of patients with diffuse large-cell lymphoma (DLCL).

PATIENTS AND METHODS

Using an enzyme-linked immunosorbent assay (ELISA; lower limit of sensitivity, 0.35 pg/mL), we measured IL-6 levels in frozen sera from 33 healthy controls and 58 untreated patients with DLCL who were enrolled onto a single combination chemotherapy protocol. Serum IL-6 levels were correlated with clinical and laboratory features at diagnosis and with failure-free and overall survival.

RESULTS

Serum IL-6 levels in the lymphoma patients (median, 4.37 pg/mL; range, < 0.35 to 110 pg/mL) were significantly higher than in the control group (median, < 0.35 pg/mL; range, < 0.35 to 1.87 pg/mL) (P < .0001). Serum IL-6 levels were higher in patients with B symptoms (P = .012), an elevated beta 2-microglobulin level (> or = 3.0 mg/L) (P = .017), and a poor performance status (P = .02). Direct linear correlations with the erythrocyte sedimentation rate (ESR), platelet count, and total WBC count, and an inverse linear correlation with the serum albumin level, were observed (all P < .02). Patients with elevated serum IL-6 levels had inferior failure-free (P = .042) and overall survival (P = .05) compared with those with normal serum IL-6 levels.

CONCLUSION

In patients with DLCL, elevated serum levels of IL-6 at diagnosis are frequent, strongly associated with many adverse disease features, and predictive of a poor failure-free and overall survival.

Calcitriol production in hypercalcemic and normocalcemic patients with non-Hodgkin lymphoma

OBJECTIVE

To determine the following: a reference range for serum calcitriol during hypercalcemia in a control group of patients with myeloma in whom calcitriol production is known to be appropriately suppressed; the incidence of elevated serum calcitriol levels in hypercalcemic patients with non-Hodgkin lymphoma according to this derived reference range; and the incidence of abnormal calcium metabolism in normocalcemic patients with non-Hodgkin lymphoma.

DESIGN

Prospective clinical study.

SETTING

Referral cancer center.

PATIENTS

2 groups of hypercalcemic patients: 16 control patients with myeloma and 22 patients with non-Hodgkin lymphoma divided into those with elevated or normal serum calcitriol levels; 1 group of 22 normocalcemic patients with non-Hodgkin lymphoma.

MEASUREMENTS

Serum chemistries and intact parathyroid hormone, calcitriol, parathyroid hormone-related protein, and urinary electrolyte levels.

RESULTS

On the basis of the mean serum calcitriol level of the control group plus 3 standard deviations, the reference range for serum calcitriol during hypercalcemia was defined as less than 42 pg/mL. Although serum calcium and parathyroid hormone levels in the study patients were similar to those in controls, 12 of the 22 hypercalcemic patients with non-Hodgkin lymphoma (55%) had serum calcitriol levels greater than 42 pg/mL (range, 51 to 170 pg/mL). No features distinguished the patients with elevated serum calcitriol levels from those with normal levels. Seventy-one percent of normocalcemic patients with non-Hodgkin lymphoma were hypercalciuric, and 18% had serum calcitriol levels greater than the normocalcemic reference range (20 to 76 pg/mL).

CONCLUSIONS

Serum calcitriol levels are elevated in most hypercalcemic patients with non-Hodgkin lymphoma in the absence of elevated serum levels of parathyroid hormone, which implicates extrarenal calcitriol production in the pathogenesis of this syndrome. Abnormal calcium metabolism, hypercalciuria, and dysregulated calcitriol production are also common in normocalcemic patients with non-Hodgkin lymphoma.

2-chlorodeoxyadenosine induces durable remissions and prolonged suppression of CD4+ lymphocyte counts in patients with hairy cell leukemia

A number of effective treatments are available for patients with hairy cell leukemia (HCL). 2-Chlorodeoxyadenosine (2-CdA) induces more than 80% complete responses, but is associated with profound suppression of CD4+ lymphocyte counts. However, the duration of each is uncertain. We have analyzed a previously reported cohort of 40 patients who had responded to 2-CdA. Eight patients (20%) have relapsed at a median of 16 months (range, 3 to 23 months). The remaining 32 patients were observed for a median of 30 months (range, 7 to 43 months). No patients have died. At 3 years, the actuarial disease-free survival rate is 77% (95% confidence interval, 70% to 84%). The median CD4+ lymphocyte count before therapy was 743/microL (range, 58 to 2,201/microL). The median CD4+ nadir after treatment was 139/microL (range, 25 to 580/microL). There was a single opportunistic infection and no second malignancies observed. Although there was evidence of some improvement in CD4+ lymphocyte counts on sequential testing, CD4+ counts remained significantly lower than baseline (P < .0001) at a median of 23 months after therapy (median, 237/microL; range, 25 to 514/microL), and were also lower than baseline (P < .002) in those patients with more than 1 year of follow-up (median, 27 months; range, 13 to 42 months). The median time to reach an absolute CD4+ lymphocyte count of 365/microL, the lower limit of the normal range, was 40 months. Although responses to 2-CdA are durable in the majority of patients with HCL, the uncertain long-term consequences of the observed CD4+ lymphocytopenia suggest caution in the broad application of this therapy.

Investigation of karyotypic, morphologic and clinical features in patients with acute myeloid leukemia blast cells expressing the neural cell adhesion molecule (CD56)

The mechanisms of extramedullary leukemic infiltration are not well characterized. The cell-surface glycoprotein CD56, which is identical to the neural cell adhesion molecule, may be involved. Using the Leu-19 antibody and flow cytometric methods, the leukemic blasts of 22% (70 of 314) of patients were CD56 positive. This was most common in acute monocytic leukemia (15 of 18, 83%) and in patients with the cytogenetic abnormalities t(8;21) (seven of 13, 54%) and trisomy 8 (nine of 22, 41%). CD56 expression was not associated with extramedullary leukemic infiltration, but was correlated with positivity for CD11b (p < 0.001), CD14 (p < 0.001) and CD19 (p = 0.018). Although associated with morphologic and cytogenetic features, CD56 expression alone cannot account for most instances of tissue infiltration in acute myeloid leukemia (AML).

Lymphomatous presentation of CD4+/CD8+ HTLV-1-related adult T-cell leukemia/lymphoma in an Iranian woman

Adult T-cell leukemia/lymphoma (ATLL) remains an uncommon disorder outside well-defined risk groups. We describe the case of an Iranian woman, who presented with isolated meningeal relapse of diffuse large-cell lymphoma. The malignant cells coexpressed CD4 and CD8 and HTLV-1 seropositivity was confirmed. Despite combination chemotherapy disseminated lymphoma developed. Preterminally the characteristic features of ATLL were noted; hypercalcemia, with normal parathyroid hormone-related protein and vitamin D levels, and peripheral blood leukemic involvement.

Acute leukemia complicating bone marrow hypoplasia in an adult with Shwachman's syndrome

Shwachman's syndrome is a rare congenital disorder associated with neutropenia and exocrine pancreatic insufficiency. We describe the development of acute myeloid leukemia in a 38-year-old patient with Shwachman's syndrome following three years of pancytopenia. After chemotherapy the leukemic clone was eradicated, however, the patient's bone-marrow hypoplasia persisted beyond 180 days with neutropenia that responded to administration of granulocyte colony-stimulating factor. Despite the patient's low erythropoietin levels, administration of erythropoietin did not improve his hemoglobin. We review previously reported cases of leukemia complicating Shwachman's syndrome with emphasis on the persistent risk of complications in patients with congenital bone-marrow failure syndromes.

Hypercalcemia in the blastic phase of chronic myeloid leukemia associated with elevated parathyroid hormone-related protein

We describe a case of hypercalcemia without lytic bone lesions complicating myeloid blast crisis of chronic myeloid leukemia (CML). Serum levels of parathyroid hormone-related protein (PTHrP) were elevated during the initial hypercalcemic period and became undetectable during chemotherapy-induced chronic phase, only to become elevated again during subsequent recurrent blastic periods repeatedly associated with hypercalcemia. Previously reported cases of hypercalcemia complicating CML are reviewed. It is suggested that PTHrP was responsible for the hypercalcemia in this case and may be an important mediator of hypercalcemia in CML.

The prognostic significance of auer rods in myelodysplasia

The category of refractory anaemia with excess blasts in transformation (RAEBt) of the French-American-British (FAB) classification system comprises a heterogeneous group of patients: those with any combination of 5% or more blood blast cells, more than 20% but no more than 30% marrow blast cells, or the presence of auer rods and 30% or less marrow blast cells. To determine the prognostic significance of auer rods in RAEBt, we classified the 208 patients with RAEBt seen between 1973 and 1992 as (1) those having RAEBt solely on the basis of auer rods (RAEBta, n = 29), (2) those meeting blood or marrow blast criteria for RAEBt and also having auer rods (RAEBtpos, n = 40) or (3) those meeting blood or marrow blast criteria for RAEBt without having auer rods (RAEBtneg, n = 139). The RAEBta group had a higher survival probability than either of the other two groups. Within RAEBta, those patients who, without auer rods, would be considered RAEB by the FAB system (n = 19) had a higher probability of survival than patients with RAEB as conventionally defined. Furthermore, patients with RAEBtpos were more likely to live longer than those with RAEBtneg. The RAEBta, RAEBtpos and RAEBtneg groups were similar with regard to the usual haematologic parameters. However, patients with auer rods were more likely to have a normal karyotype and less likely to have prognostically unfavourable cytogenetic abnormalities. When analysis was performed within cytogenetic groups, the favourable prognostic impact of auer rods was still evident. Similarly, the favourable prognostic significance of auer rods was discernible both among patients who did not receive intensive therapy and those who received induction chemotherapy. The complete remission rate in auer rod positive patients was 77%, compared to 27% in those without auer rods. There were no differences in remission duration. Our results suggest that: (1) patients with auer rods without blood or bone marrow blast criteria for RAEBt should not be grouped with those patients with such criteria, and (2) patients with auer rods and other criteria for RAEBt have a higher complete remission rate following induction therapy of the type frequently reserved for patients with acute myeloid leukaemia.

Induction of hypomagnesemia during Amsacrine treatment

Serious cardiac arrhythmias and QT interval prolongation have been reported following Amsacrine chemotherapy. The underlying mechanism is unknown. In this study, electrolyte and electrocardiographic parameters were prospectively studied in patients with acute myeloid leukemia (AML) treated with an Amsacrine containing combination chemotherapy regime. Data were collected immediately before and at 20 (+20) and 90 (+90) min after commencement of Amsacrine administration. Sixteen episodes were studied in six consecutive patients over a continuous 9 month period. One patient developed asymptomatic ventricular tachycardia during administration. Results from +20 and +90 min were compared with baseline by Wilcoxon matched pairs test. There was no significant change in potassium, albumin, or ionized calcium concentration at +20 or +90 min. The magnesium concentration at +20 min was significantly reduced (mean -0.04 mmol/liter; P < 0.05) but not so at +90 min. Sodium concentration at +20 min was significantly reduced (mean - 1.9 mmol/liter; P < 0.01). Electrocardiographic analysis showed no significant alteration in PR interval or QRS duration. Heart rate fell significantly from baseline, mean change -10 and -8 min-1 at +20 and +90 min, respectively (P < 0.01 for both). Corrected QT interval (QTc) was significantly prolonged at +20 min (+0.05) and +90 min (+0.05) (P = 0.0001 and P < 0.0001, respectively). This study confirms the high incidence of QTc prolongation with Amsacrine administration and suggests that transient hypomagnesemia may contribute to the risk of cardiac arrhythmia in this setting.