Renal failure among multiple myeloma patients utilizing carfilzomib and associated factors in the "real world".

Carfilzomib, a next-generation proteasome inhibitor, improves outcomes in patients with multiple myeloma (MM); however, a proportion of those treated develop renal failure due to adverse event, comorbidity, or myeloma progression. The rate of renal failure and associated risk factors remains unknown in real-world populations. Adults with relapsed/refractory MM who received carfilzomib between the years 2013 and 2016 were identified in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases. Renal failure was defined using the corresponding International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) diagnostic codes and procedure codes for dialysis. Patients with a pre-existing diagnosis of renal failure were excluded to distinguish an adverse event from comorbidity. Multivariate cox regression analysis was performed to identify the variables independently associated with the development of renal failure among MM patients utilizing carfilzomib. A total of 1950 patients were included in the analysis. Renal failure developed in 22% of patients during the study period. The median time to development of renal failure from first carfilzomib administration was 1.6 months (range < 0.1-23.3). Increasing age (adjusted hazard ratio [aHR] 1.01 per year, p = 0.018), pre-existing heart failure (aHR 1.50, p = 0.005), and pre-existing chronic kidney disease (aHR 2.00, p < 0.001) were associated with a higher risk of developing renal failure. Renal failure occurred in up to 22% of patients on carfilzomib therapy. The exact cause and mechanism of renal failure cannot be determined from our study and may be multifactorial. Future studies are needed to further understand the cause of renal failure among patients on carfilzomib and devise strategies to mitigate the risk.

A deficit-accumulation frailty index predicts survival outcomes in patients with gynecologic malignancy.

OBJECTIVE: To determine the association between scores from a 25-item patient-reported Rockwood Accumulation of Deficits Frailty Index (DAFI) and survival outcomes in gynecologic cancer patients. METHODS: A frailty index was constructed from the SEER-MHOS database. The DAFI was applied to women age ≥ 65 diagnosed with all types of gynecologic cancers between 1998 and 2015. The impact of frailty status at cancer diagnosis on overall survival (OS) was analyzed using Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: In this cohort (n = 1336) the median age at diagnosis was 74 (range 65-97). Nine hundred sixty-two (72%) women were Caucasian and 132 (10%) were African-American. Overall, 651(49%) of patients were considered frail. On multivariate analysis, frail patients had a 48% increased risk for death (aHR 1.48; 95% CI 1.29-1.69; P < 0.0001). Each 10% increase in frailty index was associated with a 16% increased risk of death (aHR, 1.16; 95% CI, 1.11 to 1.21; P < 0.0001). In subgroup analyses of the varying cancer types, the association of frailty status with prognosis was fairly consistent (aHR 1.15-2.24). The DAFI was more prognostic in endometrial (aHR 1.76; 95% CI 1.41-2.18, P < 0.0001) and vaginal/vulvar (aHR 1.94; 95% CI 1.34-2.81, P = 0.0005) cancers as well as patients with loco-regional disease (aHR 1.94; 95% CI 1.62-2.33, P < 0.0001). CONCLUSIONS: Frailty appears to be a significant predictor of mortality in gynecologic cancer patients regardless of chronological age. This measure of functional age may be of particular utility in women with loco-regional disease only who otherwise would have a favorable prognosis.

Disparities in health care affordability among childhood cancer survivors persist following the Affordable Care Act.

BACKGROUND: The Affordable Care Act (ACA) included many provisions that may have improved access to care for childhood cancer survivors (CCS). In this study, we sought to compare health insurance coverage and the affordability of health care among adult childhood CCS before and after the implementation of the ACA. PROCEDURE: Using data from the National Health Interview Survey (NHIS), two cohorts of CCS age 21-65 years old and matched (1:3) controls without a history of cancer were identified. A difference-in-differences analysis was used to compare insurance coverage and health care affordability pre- (2011-2013) and post-ACA (2015-2017). RESULTS: There were 309 CCS identified in the pre-ACA cohort and 324 in the post-ACA cohort. The two cohorts were similar in demographic composition. Prior to the ACA, CCS were 39% more likely to be uninsured than their peers (p = .046). Post, there was no difference in the odds of being uninsured between CCS and their peers. Following implementation of the ACA, the proportion of CCS who reported having difficulty with the affordability of health care decreased (p = .013) as did the proportion reporting skipping needed care due to cost (p < .001). However, 13% of CCS still reported being uninsured, 36% reported difficulty paying for health care, and 13% reported foregoing needed care due to cost. Relative to their peers, CCS saw improvement in foregoing needed care due to cost, but disparities still remain. CONCLUSIONS: Although improvements were observed, health care affordability, and medical nonadherence remains a problem for CCS. IMPLICATIONS FOR CANCER SURVIVORS: Additional efforts are needed to improve health care affordability among CCS.

Measuring cardiopulmonary complications of carfilzomib treatment and associated risk factors using the SEER-Medicare database.

BACKGROUND: Carfilzomib improves survival in patients with recurrent myeloma. Given the strict eligibility criteria in clinical trials, the actual frequency of cardiac adverse events (CAEs) and pulmonary adverse events (PAEs) and the risk factors associated with these AEs in the general population need to be established. METHODS: The authors extracted myeloma cases in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database from 2000 through 2013 and corresponding claims through 2014. They then identified patients who received carfilzomib during their disease course. Subsequently, the International Classification of Diseases, Ninth Revision (ICD-9) was used to identify all the codes for CAEs, PAEs, and respiratory infections associated with carfilzomib use. Preexisting diagnoses corresponding to the CAEs and PAEs of interest were excluded to distinguish toxicity from comorbidity. Multivariate Cox regression was performed to determine those variables independently associated with the development of CAEs and PAEs. RESULTS: Of the 635 patients analyzed, the median age was 72 years (range, 36-94 years); 55% of the patients were male and 79% were white. The median duration of carfilzomib treatment was 58 days (range, 1-716 days). Overall, approximately 66% of the patients had codes for either CAEs or PAEs. In terms of CAEs, approximately 22% of patients developed hypertension, 15% developed peripheral edema, and 14% experienced heart failure. With regard to PAEs, approximately 28% of patients developed dyspnea, 15% developed cough, and 15% developed pneumonia. Only chronic obstructive pulmonary disease (COPD) was found to be independently associated with the development of CAEs. Patients with preexisting COPD were found to have a 40% increase in their hazard of developing CAEs (adjusted hazard ratio, 1.40; 95% CI, 1.03-1.90). CONCLUSIONS: In older adults with myeloma who are undergoing treatment with carfilzomib, new cardiac and pulmonary diagnoses were common. Patients with preexisting COPD were found to be at an increased risk of developing CAEs.

DCEP and bendamustine/prednisone as salvage therapy for quad- and penta-refractory multiple myeloma.

Multiple myeloma (MM) almost invariably progresses through novel therapies. Patients with quad-refractory MM (refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide) and penta-refractory MM (additional refractoriness to daratumumab) have few treatment options. Two chemotherapy regimens, bendamustine/prednisone (BP) and dexamethasone, cyclophosphamide, etoposide, and cisplatin (DCEP), are often used in quad- and penta-refractory MM, but there are limited data on outcomes in this heavily pre-treated population. We conducted a single-center retrospective study to identify all patients who received DCEP and/or BP for quad- or penta-refractory MM. Disease response and refractoriness were defined by International Myeloma Working Group criteria. The primary endpoint was overall response rate (ORR). Secondary endpoints included overall survival (OS), progression-free survival (PFS), and duration of response (DOR). We identified 27 patients who received BP for quad- or penta-refractory MM. The median number of prior lines of therapy was 6. The ORR for BP was 26%. The median PFS for BP was 1.4 months (95% CI 1.1-1.6) and median OS was 8.7 months (95% CI 2.3-15.0). Patients treated with cyclophosphamide had less response to BP. Thirty-one patients received DCEP for quad-refractory or penta-refractory MM. The median number of prior treatment regimens was 8. The ORR to DCEP was 35%. The median PFS was 2.7 months (95% CI 1.5-3.8) and median OS was 6.2 months (95% CI 4.4-7.8). DCEP and BP retain efficacy in quad- and penta-refractory MM. Our analysis supports prospective study of these regimens, possibly in combination or in comparison with other agents in this area of unmet need.

Prognostic indicators in primary plasma cell leukaemia: a multicentre retrospective study of 117 patients.

We report a multicentre retrospective study that analysed clinical characteristics and outcomes in 117 patients with primary plasma cell leukaemia (pPCL) treated at the participating institutions between January 2006 and December 2016. The median age at the time of pPCL diagnosis was 61 years. Ninety-eight patients were treated with novel agents, with an overall response rate of 78%. Fifty-five patients (64%) patients underwent upfront autologous stem cell transplantation (ASCT). The median follow-up time was 50 months (95% confidence interval [CI] 33; 76), with a median overall survival (OS) for the entire group of 23 months (95% CI 15; 34). The median OS time in patients who underwent upfront ASCT was 35 months (95% CI 24·3; 46) as compared to 13 months (95% CI 6·3; 35·8) in patients who did not receive ASCT (P = 0·001). Multivariate analyses identified age ≥60 years, platelet count ≤100 × 109 /l and peripheral blood plasma cell count ≥20 × 109 /l as independent predictors of worse survival. The median OS in patients with 0, 1 or 2-3 of these risk factors was 46, 27 and 12 months, respectively (P < 0·001). Our findings support the use of novel agents and ASCT as frontline treatment in patients with pPCL. The constructed prognostic score should be independently validated.

Falls in older adults with multiple myeloma.

OBJECTIVE: To examine the prevalence of falls, factors associated with falls and the relationship between falls and survival in older adults with multiple myeloma. METHODS: In an analysis of the Surveillance, Epidemiology and End Results (SEER)-Medicare Health Outcomes Survey (MHOS)-linked database, we examined 405 older adults with multiple myeloma (MM) and 513 matched non-cancer controls. The primary outcome was self-reported within the past 12 months. Age, race, gender, symptoms, and comorbidities were self-reported in the MHOS. Survival was calculated from SEER data. RESULTS: Of the patients with MM, 171 were within 1 year of diagnosis (cohort 1) and 234 were ≥1 year postdiagnosis (cohort 2). Patients in cohorts 1 and 2 were more likely to have fallen than controls (26% and 33% vs 23%, P = .012). On multivariate analysis, among patients with myeloma (combined cohorts 1 and 2), factors associated with falls included self-report of fatigue (aOR 2.52 [95% CI 1.34-4.93]), depression (aOR 1.90 [95% CI 1.14-3.18]), or poorer general health (aOR 1.86 [95% CI 1.05-3.36]). Falls were not associated with survival. CONCLUSIONS: Older adults with MM have a greater prevalence of falls than matched controls. Self-reported fatigue, depression, and poorer general health are associated with greater odds of falls.

Fresh or Cryopreserved CD34+-Selected Mobilized Peripheral Blood Stem and Progenitor Cells for the Treatment of Poor Graft Function after Allogeneic Hematopoietic Cell Transplantation.

CD34+-selected stem cell boost (SCB) without conditioning has recently been utilized for poor graft function (PGF) after allogeneic hematopoietic stem cell transplantation with promising results. Unfortunately, many patients have been unable to receive the boost infusion as their donors were unwilling or unable to undergo an additional stem cell collection. Therefore, we conducted this study utilizing either fresh or cryopreserved peripheral blood stem cell products to create CD34+-selected boost infusions for the treatment of PGF. Additionally, to explore relationship of CD34+ dose and response, we included a cohort of donors mobilized with plerixafor in addition to the standard granulocyte colony-stimulating factor (G-CSF). Twenty-six patients with PGF were included in this study. Seventeen donor-recipient pairs were enrolled onto the prospective study; an additional 9 patients treated off protocol were reviewed retrospectively. Three different donor products were used for CD34+ selection: (1) fresh mobilized product using G-CSF only, (2) fresh mobilized products using G-CSF and plerixafor, and (3) cryopreserved cells mobilized with G-CSF. CD34+ cell selection was performed using a CliniMACS. The infusion was not preceded by administration of any chemotherapy or conditioning regimen. The primary objective was hematologic response rate and secondary objectives included CD34+ yields, incidence and severity of acute and chronic graft-versus-host disease (GVHD), overall survival (OS), and relapse-free survival (RFS). The median post-selection CD34+ counts per kilogram of recipient weight were 3.1 × 106, 10.9 × 106, and 1 × 106 for G-CSF only, G-CSF plus plerixafor, and cryopreserved products, respectively. The median CD34+ yields (defined as the number of CD34+ cells after selection/CD34+ cells before CD34+ selection) were 69%, 66%, and 28% for G-CSF only, G-CSF plus plerixafor, and cryopreserved products, respectively. After SCB, 16 of the 26 recipients (62%) had a complete response, including 5 of 8 (63%) who received cryopreserved products. Five had a partial response (19%), resulting in an overall response rate of 81%. One-year RFS and OS were 50% and 65%, respectively. There was no treatment-related toxicity reported other than GVHD: 6 (23%) developed acute GVHD (2 grade I and 4 grade II) and 8 (31%) developed chronic GVHD (2 limited and 6 extensive). Cryopreserved products are viable alternatives to create SCB for the treatment of PGF. When collecting fresh products is an option, the addition of plerixafor increases CD34+ yield over G-CSF alone; however, it is currently unclear if the CD34+ cell dose impacts the efficacy of the SCB.

Results of a Prospective Randomized, Open-Label, Noninferiority Study of Tbo-Filgrastim (Granix) versus Filgrastim (Neupogen) in Combination with Plerixafor for Autologous Stem Cell Mobilization in Patients with Multiple Myeloma and Non-Hodgkin Lymphoma.

Autologous hematopoietic stem cell transplantation (auto-HSCT) improves survival in patients with multiple myeloma (MM) and non-Hodgkin lymphoma (NHL). Traditionally, filgrastim (Neupogen; recombinant G-CSF) has been used in as a single agent or in combination with plerixafor for stem cell mobilization for auto-HSCT. In Europe, a biosimilar recombinant G-CSF (Tevagrastim) has been approved for various indications similar to those of reference filgrastim, including stem cell mobilization for auto-HSCT; however, in the United States, tbo-filgrastim (Granix) is registered under the original biological application and is not approved for stem cell mobilization. In retrospective studies, stem cell mobilization with tbo-filgrastim has shown similar efficacy and toxicity as filgrastim, but no prospective studies have been published to date. We have conducted the first prospective randomized trial comparing the safety and efficacy of tbo-filgrastim in combination with plerixafor with that of filgrastim in combination with plerixafor for stem cell mobilization in patients with MM and NHL. This is a phase 2 prospective randomized (1:1) open-label single-institution noninferiority study of tbo-filgrastim and filgrastim with plerixafor in patients with MM or NHL undergoing auto-HSCT. Here 10 µg/kg/day of tbo-filgrastim/filgrastim was administered s.c. for 5 days (days 1 to 5). On day 4 at approximately 1800 hours, 0.24 mg/kg of plerixafor was administered s.c. Apheresis was performed on day 5 with a target cumulative collection goal of at least 5.0 × 106 CD34+ cells/kg. The primary objective was to compare day 5 CD34+ cells/kg collected. Secondary objectives included other mobilization endpoints, safety, engraftment outcomes, and hospital readmission rate. A total of 97 evaluable patients were enrolled (tbo-filgrastim, n = 46; filgrastim, n = 51). Tbo-filgrastim was not inferior to filgrastim in terms of day 5 CD34+ cell collection (mean, 11.6 ± 6.7 CD34+ cells/kg versus 10.0 ± 6.8 CD34+ cells/kg. Multivariate analysis revealed a trend toward increased mobilization in the tbo-filgrastim arm, but this was not statistically significant. The tbo-filgrastim and filgrastim arms were similar in all secondary endpoints. Tbo-filgrastim is not inferior in efficacy and has similar safety compared to reference filgrastim when used for stem cell mobilization in patients with MM and NHL. Granix can be safely used instead of Neupogen for stem cell collection in patients undergoing auto-HSCT for MM or NHL. The study is registered at https://clinicaltrials.gov/ct2/show/NCT02098109.

Racial disparities in treatment use for multiple myeloma.

BACKGROUND: Recent treatment advances have greatly improved the prognosis of patients with multiple myeloma. However, some of these newer, more effective treatments are intensive and expensive and their use remains low, particularly among black patients. METHODS: In the current study, the authors reviewed the use patterns of stem cell transplantation and bortezomib using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. RESULTS: After controlling for overall health and potential access barriers, black patients were found to be 37% (P<.0001) less likely to undergo stem cell transplantation, and 21% (P<.0001) less likely to be treated with bortezomib. Moreover, the authors found that the underuse of these treatments was associated with a 12% increase in the hazard ratio for death among black patients (P = 0.0007). CONCLUSIONS: Eliminating health disparities, a current focus of US public policy, is highly complex, as illustrated by the results of the current study. In patients with multiple myeloma, treatment disparities are not completely explained by potential access barriers. Additional factors, such as structural barriers in the health care system and individual decision making among black and white patients, must be explored to fully explain the disparity. Cancer 2017;123:1590-1596. © 2017 American Cancer Society.

IgM myeloma: A multicenter retrospective study of 134 patients.

IgM myeloma is a rare hematologic malignancy for which the clinicopathological features and patient outcomes have not been extensively studied. We carried out a multicenter retrospective study in patients with diagnosis of IgM myeloma defined by >10% marrow involvement by monoclonal plasma cells, presence of an IgM monoclonal paraproteinemia of any size, and anemia, renal dysfunction, hypercalcemia, lytic lesions and/or t(11;14) identified by FISH. A total of 134 patients from 20 centers were included in this analysis. The median age at diagnosis was 65.5 years with a male predominance (68%). Anemia, renal dysfunction, elevated calcium and skeletal lytic lesions were found in 37, 43, 19, and 70%, respectively. The median serum IgM level was 2,895 mg dL-1 with 19% of patients presenting with levels >6,000 mg dL-1 . International Staging System (ISS) stages 1, 2, and 3 were seen in 40 (33%), 54 (44%), and 29 (24%) of patients, respectively. The malignant cells expressed CD20 (58%) and cyclin D1 (67%), and t(11;14) was the most common cytogenetic finding (39%). The median overall survival (OS) was 61 months. Higher ISS score was associated with worse survival (P = 0.02). Patients with IgM myeloma present with similar characteristics and outcomes as patients with more common myeloma subtypes.

Remobilization of hematopoietic stem cells in healthy donors for allogeneic transplantation.

BACKGROUND: The need to repeat peripheral blood (PB) stem cell mobilization and collection in healthy donors arises infrequently but may be required due to insufficient initial collection, graft failure, or relapse of the recipient's disease. Little data exist on the efficacy of remobilization. Therefore, we retrospectively reviewed 18 years of remobilization records from healthy stem cell donors at our institution. STUDY DESIGN AND METHODS: We identified 62 healthy donors who underwent remobilization, a cohort of 30 mobilized and remobilized with cytokines and a cohort of 32 mobilized with a CXCR4 antagonist and remobilized with cytokines. For each cohort we compared the PB CD34+/L level, the number of CD34+ cells collected/kg (recipient weight), and the number of CD34+ cells/L collected on the first day of leukapheresis during initial mobilization and remobilization. RESULTS: Initial mobilization with cytokines was associated with reduced remobilization. The mean PB CD34/L level at initial mobilization was 69 × 10(6) compared to 37 × 10(6) at remobilization (p = 0.029). In contrast, initial mobilization with a CXCR4 antagonist was not associated with reduced remobilization. The mean PB CD34/L level at initial mobilization was 15 × 10(6) compared to 68 × 10(6) at remobilization (p < 0.001). In both cohorts, initial mobilization results were positively correlated with remobilization results but the interval between was not. CONCLUSIONS: This study suggests that poor remobilization yields may be due to decreased efficacy of cytokines after repeat exposure. The underlying mechanism of these findings remains unclear and further studies are needed.

Central nervous system involvement by multiple myeloma: A multi-institutional retrospective study of 172 patients in daily clinical practice.

The multicenter retrospective study conducted in 38 centers from 20 countries including 172 adult patients with CNS MM aimed to describe the clinical and pathological characteristics and outcomes of patients with multiple myeloma (MM) involving the central nervous system (CNS). Univariate and multivariate analyses were performed to identify prognostic factors for survival. The median time from MM diagnosis to CNS MM diagnosis was 3 years. Thirty-eight patients (22%) were diagnosed with CNS involvement at the time of initial MM diagnosis and 134 (78%) at relapse/progression. Upon diagnosis of CNS MM, 97% patients received initial therapy for CNS disease, of which 76% received systemic therapy, 36% radiotherapy and 32% intrathecal therapy. After a median follow-up of 3.5 years, the median overall survival (OS) from the onset of CNS involvement for the entire group was 7 months. Untreated and treated patients had median OS of 2 and 8 months, respectively (P < 0.001). At least one previous line of therapy for MM before the diagnosis of CNS disease and >1 cytogenetic abnormality detected by FISH were independently associated with worse OS. The median OS for patients with 0, 1 and 2 of these risk factors were 25 months, 5.5 months and 2 months, respectively (P < 0.001). Neurological manifestations, not considered chemotherapy-related, observed at any time after initial diagnosis of MM should raise a suspicion of CNS involvement. Although prognosis is generally poor, the survival of previously untreated patients and patients with favorable cytogenetic profile might be prolonged due to systemic treatment and/or radiotherapy. Am. J. Hematol. 91:575-580, 2016. © 2016 Wiley Periodicals, Inc.

Re: Disparities in Utilization of Autologous Hematopoietic Cell Transplantation for Treatment of Multiple Myeloma.

Costa et al. recently reported that racial disparities prevented nearly 40% of non-Hispanic blacks with multiple myeloma (MM) from undergoing stem cell transplantation (SCT), but the authors were unable to provide an explanation for the disparities because of limitations of their datasets. They hypothesized that socioeconomic status (SES) and/or insurance providers might account for the disparity. To examine the issue raised by Costa et al., we performed a secondary analysis using hierarchical multivariate logistic regression with data previously collected to determine if age at diagnosis, sex, SES, primary insurance provider at diagnosis, and comorbidity score help explain the racial disparities in SCT utilization. A model of race, age, sex, SES, insurance provider, and comorbidity score was the most accurate model in predicting stem cell utilization status (χ(2)[12] = 193.859; P < .001; area under the curve = .837; P < .001). After controlling for the covariates, black patients were less likely to undergo SCT than white patients (adjusted odds ratio, .49; 95% confidence interval, .27 to .89; P = .013). In conclusion, we also observed racial disparities between black and white patients with MM in SCT utilization and these are not fully accounted for by the covariates age, sex, SES, insurance provider, and comorbidity score.

Maintenance Therapy with Decitabine after Allogeneic Stem Cell Transplantation for Acute Myelogenous Leukemia and Myelodysplastic Syndrome.

Decitabine is a hypomethylating agent that irreversibly inhibits DNA methyltransferase I, inducing leukemic differentiation and re-expression of epigenetically silenced putative tumor antigens. We assessed safety and efficacy of decitabine maintenance after allogeneic transplantation for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Decitabine maintenance may help eradicate minimal residual disease, decrease the incidence of graft-versus-host disease (GVHD), and facilitate a graft-versus-leukemia effect by enhancing the effect of T regulatory lymphocytes. Patients with AML/MDS in complete remission (CR) after allotransplantation started decitabine between day +50 and +100. We investigated 4 decitabine doses in cohorts of 4 patients: 5, 7.5, 10, and 15 mg/m(2)/day × 5 days every 6 weeks, for a maximum 8 cycles. The maximum tolerated dose (MTD) was defined as the maximum dose at which ≤ 25% of people experience dose-limiting toxicities during the first cycle of treatment. Twenty-four patients were enrolled and 22 were evaluable. All 4 dose levels were completed and no MTD was reached. Overall, decitabine maintenance was well tolerated. Grade 3 and 4 hematological toxicities were experienced by 75% of patients, including all patients treated at the highest dose level. Nine patients completed all 8 cycles and 8 of them remain in CR. Nine patients died from relapse (n = 4), infectious complications (n = 3), and GVHD (n = 2). Most occurrences of acute GVHD were mild and resolved without interruption of treatment; 1 patient died of acute gut GVHD. Decitabine maintenance did not clearly impact the rate of chronic GVHD. Although there was a trend of increased FOXP3 expression, results were not statistically significant. In conclusion, decitabine maintenance is associated with acceptable toxicities when given in the post-allotransplantation setting. Although the MTD was not reached, the dose of 10 mg/m(2) for 5 days every 6 weeks appeared to be the optimal dose rather than 15 mg/m(2), where most hematological toxicities occurred.