Immunosuppressive therapy of LGL leukemia: prospective multicenter phase II study by the Eastern Cooperative Oncology Group (E5998).

Failure to undergo activation-induced cell death due to global dysregulation of apoptosis is the pathogenic hallmark of large granular lymphocyte (LGL) leukemia. Consequently, immunosuppressive agents are rational choices for treatment. This first prospective trial in LGL leukemia was a multicenter, phase 2 clinical trial evaluating methotrexate (MTX) at 10 mg/m(2) orally weekly as initial therapy (step 1). Patients failing MTX were eligible for treatment with cyclophosphamide at 100 mg orally daily (step 2). The overall response in step 1 was 38% with 95% confidence interval (CI): 26 and 53%. The overall response in step 2 was 64% with 95% CI: 35 and 87%. The median overall survival for patients with anemia was 69 months with a 95% CI lower bound of 46 months and an upper bound not yet reached. The median overall survival for patients with neutropenia has not been reached 13 years from study activation. Serum biomarker studies confirmed the inflammatory milieu of LGL but were not a priori predictive of response. We identify a gene expression signature that correlates with response and may be STAT3 mutation driven. Immunosuppressive therapies have efficacy in LGL leukemia. Gene signature and mutational profiling may be an effective tool in determining whether MTX is an appropriate therapy.

Peripheral T-cell lymphomas in a large US multicenter cohort: prognostication in the modern era including impact of frontline therapy.

BACKGROUND: Optimal frontline therapy for peripheral T-cell lymphoma (PTCL) in the modern era remains unclear. PATIENTS AND METHODS: We examined patient characteristics, treatment, and outcomes among 341 newly diagnosed PTCL patients from 2000 to 2011. Outcome was compared with a matched cohort of diffuse large B-cell lymphoma (DLBCL) patients, and prognostic factors were assessed using univariate and multivariate analyses. RESULTS: PTCL subtypes included PTCL, not otherwise specified (PTCL-NOS) (31%), anaplastic large T-cell lymphoma (ALCL) (26%), angioimmunoblastic T-cell lymphoma (23%), NK/T-cell lymphoma (7%), acute T-cell leukemia/lymphoma (6%), and other (7%). Median age was 62 years (range 18-95 years), and 74% had stage III-IV disease. Twenty-three (7%) patients received only palliative care whereas 318 received chemotherapy: CHOP-like regimens (70%), hyperCVAD/MA (6%), or other (18%). Thirty-three patients (10%) underwent stem-cell transplantation (SCT) in first remission. The overall response rate was 73% (61% complete); 24% had primary refractory disease. With 39-month median follow-up, 3-year progression-free survival (PFS) and overall survival (OS) were 32% and 52%. PFS and OS for PTCL patients were significantly inferior to matched patients with DLBCL. On multivariate analysis, stage I-II disease was the only significant pretreatment prognostic factor [PFS: hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.34-0.85, P = 0.007; OS: HR 0.42, 95% CI 0.22-0.78, P = 0.006]. ALK positivity in ALCL was prognostic on univariate analysis, but lost significance on multivariate analysis. The most dominant prognostic factor was response to initial therapy (complete response versus other), including adjustment for stage and SCT [PFS: HR 0.19, 95% CI 0.14-0.28, P < 0.0001; OS: HR 0.26, 95% CI 0.17-0.40, P < 0.0001]. No overall survival difference was observed based on choice of upfront regimen or SCT in first remission. CONCLUSIONS: This analysis identifies early-stage disease and initial treatment response as dominant prognostic factors in PTCL. No clear benefit was observed for patients undergoing consolidative SCT. Novel therapeutic approaches for PTCL are critically needed.

A multicenter phase II study incorporating high-dose rituximab and liposomal doxorubicin into the CODOX-M/IVAC regimen for untreated Burkitt's lymphoma.

BACKGROUND: Despite improvement with intensive multi-agent chemotherapy, 2-year progression-free survival (PFS) rates for adults with high-risk Burkitt's lymphoma (BL) remains <55%. PATIENTS AND METHODS: We conducted a phase II trial for newly diagnosed classic BL utilizing liposomal doxorubicin (Adriamycin) in lieu of doxorubicin and incorporating intravenous rituximab (at 500 mg/m(2) twice/cycle) into the CODOX-M/IVAC regimen. Correlative analyses included paired serum and cerebrospinal fluid (CSF) rituximab levels and close examination of cardiac function. RESULTS: Among 25 BL patients, the median age was 44 years (23-70) and 4 patients were HIV positive. There were 20 high-risk and 5 low-risk patients. At baseline, 40% of high-risk patients had bone marrow involvement, 35% had bulky disease and 15% had central nervous system involvement. The overall response rate was 100% (complete remission 92%). At 34-month median follow-up, the 2-year PFS and overall survival (OS) rates for all patients were 80% and 84%, respectively (low-risk: both 100%; high-risk: 76% and 81%, respectively). Furthermore, the 2-year PFS, OS, and disease-specific survival (DSS) rates for high-risk, HIV-negative patients were 84%, 89% and 100%, respectively. Adverse events (AEs) appeared to be consistent with prior CODOX-M/IVAC data, although there were several grade 3 cardiac events noted (all declined ejection fraction without clinical symptoms). The mean serum rituximab levels at 24 h after cycles 1 and 3 for patients without relapse were 258 and 306 µg/ml, respectively, versus 131 and 193 µg/ml, respectively, for patients with early progression (P = 0.002 and 0.002, respectively). The mean CSF rituximab levels for all patients were 0.11 and 0.24 µg/ml, respectively, at cycle 1 (24/72 h), which equated to serum:CSF ratios of 0.05% and 0.20%, respectively. CONCLUSIONS: The integration of rituximab into CODOX-M/IVAC for adult BL was feasible and tolerable, while changes in cardiac function warrant continued examination. This regimen was associated with excellent survival rates for HIV-negative BL. Further investigation of the predictive value of serum rituximab is needed. Clinicaltrials.gov NCT00392990.

Primary CNS posttransplant lymphoproliferative disease (PTLD): an international report of 84 cases in the modern era.

We performed a multicenter, International analysis of solid organ transplant (SOT)-related primary central nervous system (PCNS) posttransplant lymphoproliferative disease (PTLD). Among 84 PCNS PTLD patients, median time of SOT-to-PTLD was 54 months, 79% had kidney SOT, histology was monomorphic in 83% and tumor was EBV+ in 94%. Further, 33% had deep brain involvement, 10% had CSF involvement, while none had ocular disease. Immunosuppression was reduced in 93%; additional first-line therapy included high-dose methotrexate (48%), high-dose cytarabine (33%), brain radiation (24%) and/or rituximab (44%). The overall response rate was 60%, while treatment-related mortality was 13%. With 42-month median follow-up, three-year progression-free survival (PFS) and overall survival (OS) were 32% and 43%, respectively. There was a trend on univariable analysis for improved PFS for patients who received rituximab and/or high-dose cytarabine. On multivariable Cox regression, poor performance status predicted inferior PFS (HR 2.61, 95% CI 1.32-5.17, p = 0.006), while increased LDH portended inferior OS (HR 4.16, 95% CI 1.29-13.46, p = 0.02). Moreover, lack of response to first-line therapy was the most dominant prognostic factor on multivariable analysis (HR 8.70, 95% CI 2.56-29.57, p = 0.0005). Altogether, PCNS PTLD appears to represent a distinct clinicopathologic entity within the PTLD spectrum that is associated with renal SOT, occurs late, is monomorphic and retains EBV positivity.

An open-label, multicenter, phase II study of bevacizumab for the treatment of angiosarcoma and epithelioid hemangioendotheliomas.

BACKGROUND: To determine efficacy and safety of bevacizumab, a recombinant humanized antibody against vascular endothelial growth factor (VEGF), in the treatment of metastatic or locally advanced angiosarcoma and epithelioid hemangioendotheliomas. PATIENTS AND METHODS: In this single-arm phase II trial, 32 patients were enrolled and they received bevacizumab 15 mg/kg IV infusion in 21-day cycles. Patients had disease that was deemed not surgically resectable, Eastern Cooperative Oncology Group (ECOG) performance status of ≤1, adequate organ function and had not received any radiation treatment in the last 28 days. RESULTS: Of the 30 patients evaluated for efficacy and toxic effect, four (two angiosarcoma and two epithelioid hemangioendothelioma; 17%) had a partial response. Fifteen patients (11 angiosarcoma and 4 epithelioid hemangioendothelioma; 50%) showed stable disease with a mean time to progression of 26 weeks. Bevacizumab was well tolerated with only one grade 4 adverse event. Expected known toxic effects of the drug were manageable. CONCLUSION: Bevacizumab is an effective and well-tolerated treatment for metastatic or locally advanced angiosarcoma and epithelioid hemangioendotheliomas. Further phase III studies of bevacizumab in combination with other chemotherapeutic agents and/or radiation treatment are warranted.

Racial disparities in Hodgkin's lymphoma: a comprehensive population-based analysis.

BACKGROUND: Racial disparity has been investigated in a number of cancers; however, there remains a comparative paucity of data in Hodgkin's lymphoma (HL). PATIENTS AND METHODS: We examined time-, age-, and gender-specific incidence, disease characteristics, and survival across and within races for adolescent/adult HL (age 10-79 years) diagnosed during 1992-2007 in the SEER 13 registries. RESULTS: A total of 15 662 HL cases were identified [11,211 non-Hispanic whites, 2067 Hispanics, 1662 blacks, and 722 Asian/Pacific Islanders (A/PI)]. Similar to whites, A/PIs had bimodal age-specific incidence, while blacks and Hispanics did not. Further, HL was significantly more common in Hispanics versus whites age>65 years (7.0/1×10(6) versus 4.5/1×10(6), respectively, P<0.01). By place of birth, US-born Hispanics and A/PIs age 20-39 years had higher incidence of HL versus their foreign-born counterparts (P<0.05), however, rates converged age>40 years. Interestingly, from 1992-1997 to 2003-2007, A/PI incidence rates increased >50% (P<0.001). Moreover, this increase was restricted to US-born A/PI. We also identified a number of disease-related differences based on race. Finally, 5-, 10-, and 15-year overall survival rates were inferior for blacks and Hispanics compared with whites (P<0.005 and P<0.001, respectively) and A/PI (P<0.018 and P<0.001, respectively). These differences persisted on multivariate analysis. CONCLUSION: Collectively, we identified multiple racial disparities, including survival, in adolescent/adult HL.

Rituximab-associated hepatitis B virus (HBV) reactivation in lymphoproliferative diseases: meta-analysis and examination of FDA safety reports.

BACKGROUND: Rituximab has been associated with hepatitis B virus reactivation (HBV-R). However, the characteristics and scope of this association remain largely undefined. METHODS: We completed a comprehensive literature search of all published rituximab-associated HBV-R cases and from the Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) MedWatch database. Literature and FDA cases were compared for completeness, and a meta-analysis was completed. RESULTS: One hundred and eighty-three unique cases of rituximab-associated HBV-R were identified from the literature (n = 27 case reports, n = 156 case series). The time from last rituximab to reactivation was 3 months (range 0-12), although 29% occurred >6 months after last rituximab. Within FDA data (n = 118 cases), there was a strong signal for rituximab-associated HBV-R [proportional reporting ratio = 28.5, 95% confidence interval (CI) 23.9-34.1; Empiric Bayes Geometric Mean = 26.4, 95% CI 21.4-31.1]. However, the completeness of data in FDA reports was significantly inferior compared with literature cases (P < 0.0001). Among HBV core antibody (HBcAb(+)) series, the pooled effect of rituximab-based therapy showed a significantly increased risk of HBV-R compared with nonrituximab-treated patients (odds ratio 5.73, 95% CI 2.01-16.33; Z = 3.33, P = 0.0009) without heterogeneity (χ(2) = 2.12, P = 0.5473). CONCLUSIONS: The FDA AERS provided strong HBV-R safety signals; however, literature-based cases provided a significantly more complete description. Furthermore, meta-analysis of HBcAb(+) series identified a more than fivefold increased rate of rituximab-associated HBV-R.

Actual or ideal body weight to calculate CD34+ cell dose in patients undergoing autologous hematopoietic SCT for myeloma?

CD34+ cell dose calculations are usually based on actual body weight (ABW). We have shown that ideal body weight (IBW) may provide a better basis for this in a small population of patients with hematologic malignancies. This was studied further in 514 myeloma autografts. The CD34+ cell doses (10(6)/kg) by IBW and ABW were 1.37-39.36 (median 6.03) and 1.15-29.67 (median 4.84), respectively. IBW-based cell doses correlated slightly better with engraftment than ABW-based doses (higher r(2)): 0.5 x 10(9)/l neutrophils 0.83 versus 0.82, 1.0 x 10(9)/l neutrophils 0.78 versus 0.77, 20 x 10(9)/l platelets 0.54 versus 0.53 and 50 x 10(9)/l platelets 0.57 versus 0.55. When outliers (hematologic recovery in <8 or >16 days) were excluded, the findings were similar: 0.5 x 10(9)/l neutrophils 0.85 versus 0.84, 1.0 x 10(9)/l neutrophils 0.85 versus 0.84, 20 x 10(9)/l platelets 0.86 versus 0.85 and 50 x 10(9)/l platelets 0.85 versus 0.84. CD34+ cell doses based on IBW as well as ABW significantly affected engraftment when analyzed separately as continuous variables. However, when analyzed together, only the dose based on IBW retained significance. We conclude that calculation of CD34+ cell numbers for autotransplantation should be based on IBW.

Granulocyte-colony stimulating factor administration to healthy individuals and persons with chronic neutropenia or cancer: an overview of safety considerations from the Research on Adverse Drug Events and Reports project.

Granulocyte-colony stimulating factor (G-CSF) is widely administered to donors who provide peripheral blood stem cells (PBSC) for individuals who undergo hematopoietic stem cell transplants. Questions have been raised about the safety of G-CSF in this setting. Herein, the Research on Adverse Drug Events and Reports (RADAR) project investigators reviewed the literature on G-CSF-associated adverse events in healthy individuals or persons with chronic neutropenia or cancer. Toxicities identified included bone pain and rare instances of splenic rupture, allergic reactions, flares of underlying autoimmune disorders, lung injury and vascular events. Among healthy individuals, four patients developed splenic rupture shortly after G-CSF administration and three patients developed acute myeloid leukemia 1 to 5 years after G-CSF administration. Registry studies identified no increased risks of malignancy among healthy individuals who received G-CSF before PBSC harvesting. However, more than 2000 donors would have to be followed for 10 years to detect a 10-fold increase in leukemia risk. Our review identifies bone pain as the most common toxicity of G-CSF administration. There are questions about a causal relationship between G-CSF administration and acute leukemia, but more long-term safety data from database registries are needed to adequately evaluate such a relationship.

Breakthrough fungal infections after allogeneic hematopoietic stem cell transplantation in patients on prophylactic voriconazole.

Seventy-one allograft recipients receiving voriconazole, in whom complete clinical, microbiologic and pharmacokinetic data were available, were studied to determine the efficacy of voriconazole in preventing fungal infections. The length of voriconazole therapy was 6-956 days (median 133). The total number of patient-days on voriconazole was 13 805 ( approximately 38 years). A total of 10 fungal infections were seen in patients on voriconazole (18% actuarial probability at 1 year): Candida glabrata (n=5), Candida krusei (n=1), Cunninghamella (n=1), Rhizopus (n=2) and Mucor (n=1). Two of the four zygomycosis cases were preceded by short durations of voriconazole therapy, but prolonged itraconazole prophylaxis. The plasma steady-state trough voriconazole levels around the time the infection occurred were <0.2, <0.2, 0.33, 0.55, 0.63 and 1.78 microg/ml in the six candidiasis cases. Excluding the four zygomycosis cases, all the six candidiasis cases were seen among the 43 patients with voriconazole levels of < or =2 microg/ml and none among the 24 with levels of >2 microg/ml (P=0.061). We conclude that voriconazole is effective at preventing aspergillosis. However, breakthrough zygomycosis is seen in a small proportion of patients. The role of therapeutic voriconazole monitoring with dose adjustment to avoid breakthrough infections with fungi that are otherwise susceptible to the drug needs to be explored prospectively.

Phase I/II trial of total lymphoid irradiation and high-dose chemotherapy with autologous stem-cell transplantation for relapsed and refractory Hodgkin's lymphoma.

BACKGROUND: The standard approach to treatment of relapsed/refractory Hodgkin's lymphoma (HL) is high-dose chemotherapy conditioning followed by autologous hematopoietic stem-cell transplantation (aHSCT). We report the results of a prospective phase I/II clinical trial of accelerated hyperfractionated total lymphoid irradiation (TLI) immediately followed by high-dose chemotherapy for relapsed/refractory HL. PATIENTS AND METHODS: Forty-eight patients underwent aHSCT with either sequential TLI/chemotherapy (n = 32) or chemotherapy-alone conditioning (n = 16), based on prior radiation exposure. The first 22 patients enrolled on trial received escalating doses of etoposide (1600-2100 mg/m(2)) with high-dose carboplatin and cyclophosphamide. RESULTS: No dose-limiting toxicity was seen and TLI/chemotherapy was well tolerated. The 5-year event-free survival (EFS) estimate for all patients was 44% with overall survival (OS) of 48%. Five-year EFS and OS for the TLI/chemotherapy group was 63% and 61%, respectively, compared with 6% and 27%, respectively, for the chemotherapy-alone group (P < 0.0001 and P = 0.04, respectively). Patients with primary induction failure HL who received TLI/chemotherapy had 5-year EFS and OS rate of 83%. The 100-day treatment-related mortality was 4.2% and two secondary cancers were seen. Significant factors predicting survival by multivariate analysis included TLI/chemotherapy conditioning and B symptoms at relapse. CONCLUSIONS: Sequential TLI/chemotherapy conditioning for relapsed/refractory HL is safe and associated with excellent long-term survival rates.

Breakthrough zygomycosis after voriconazole administration among patients with hematologic malignancies who receive hematopoietic stem-cell transplants or intensive chemotherapy.

Zygomycosis is increasingly reported as a cause of life-threatening fungal infections. A higher proportion of cases reported over the last decades have been in cancer patients, with or without hematopoietic stem cell transplantation (HSCT). The new anti-fungal agent voriconazole is a recently identified risk factor for developing zygomycosis. We reviewed the clinical characteristics and outcomes of a large cohort of cancer patients who developed zygomycosis after exposure to voriconazole. Health care professionals at 13 large cancer centers provided clinical information on cancer patients with zygomycosis and prior exposure to voriconazole. Criteria for inclusion were 5 days or more of voriconazole use and diagnostic confirmation with tissue or histology. Fifty-eight cases were identified among patients with hematologic malignancies, 62% including patients who underwent a HSCT procedure. Fifty-six patients received voriconazole for primary or secondary prophylaxis against fungal infection. In addition to prior exposure to voriconazole, patients also had several of the previously established risk factors for zygomycosis. Amphotericin B was the most commonly prescribed anti-fungal therapy. Overall mortality was 73%. We conclude that zygomycosis after exposure to voriconazole is a recently described entity that is frequently fatal, despite treatment with currently available anti-fungal agents and surgery.

Does younger donor age affect the outcome of reduced-intensity allogeneic hematopoietic stem cell transplantation for hematologic malignancies beneficially?

Sixty three patients aged 27-66 years (median 52) were allografted from HLA-matched sibling (n=47), 10 of 10 allele-matched unrelated (n=19), or one-antigen/allele-mismatched (n=7) donors aged 24-69 years (median 46) after a conditioning regimen comprising 100 mg/m(2) melphalan. Cyclophosphamide (50 mg/kg) was also administered to patients who had not been autografted previously. Cyclosporine or tacrolimus, and mycophenolate mofetil were administered to prevent graft-versus-host disease (GVHD). The 2-year cumulative incidences of relapse and TRM were 55 and 24% respectively, and 2-year probabilities of overall survival (OS) and disease-free survival (DFS) were 36 and 21%, respectively. Poor performance status, donor age >45 years and elevated lactate dehydrogenase (LDH) increased the risk of treatment-related mortality (TRM), refractory disease and donor age >45 years increased the risk of relapse, and OS and DFS were adversely influenced by refractory disease, poor performance status, increased LDH, and donor age >45 years. Our data suggest that younger donor age is associated with better outcome after sub-myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) for hematologic malignancies due to lower TRM and relapse. This finding raises the question of whether a young 10-allele-matched unrelated donor is superior to an older matched sibling donor in patients where the clinical situation permits a choice between such donors.

Reduced-dose rasburicase (recombinant xanthine oxidase) in adult cancer patients with hyperuricemia.

Recombinant urate oxidase (rasburicase) lowers uric acid levels rapidly to very low levels at the labeled dose of 0.15-0.2 mg/kg daily for 5 days. Our past experience showed that a lower dose (3 mg) lowered uric acid levels sufficiently in most patients. A retrospective review was conducted to determine the effect of a fixed 3 mg dose of rasburicase in 43 adult patients with cancer undergoing hematopoietic stem cell transplantation or receiving chemotherapy who had elevated or rising uric acid levels (6.4-16.8 mg/dl; median 9.6). Six patients received a second dose of rasburicase (3 mg in four patients and 1.5 mg in two patients) 24 h later. Patients received allopurinol, adequate hydration, as well as other supportive therapy as required. Uric acid levels declined by 6-95% (median 43%) within the first 24 h after rasburicase administration, and levels at 48 h were 9-91% (median 65%) lower than the baseline levels. Serum creatinine changed by < or =10% in 21 patients, increased by >10% in four patients and decreased by >10% in 18 patients. No significant renal dysfunction developed in any of the patients. We conclude that rasburicase is effective in lowering uric acid levels at a fixed dose of 3 mg, which is much lower than the recommended dose.

Ideal rather than actual body weight should be used to calculate cell dose in allogeneic hematopoietic stem cell transplantation.

Whether the CD34+ and CD3+ cell doses in allogeneic HSCT should be estimated using actual (ABW) or ideal (IBW) body weight has never been definitively determined. We have shown that CD34+ cell doses based upon IBW are better predictive of engraftment after autologous and allogeneic HSCT. Sixty-three patients undergoing reduced-intensity HSCT after a uniform preparative regimen were evaluated to determine the effect of cell dose. ABW and IBW were 45-147 kg (median 79) and 52-85 kg (median 67) respectively. The ABW-IBW difference was -24% to +133% (median +16%); nine patients were >5% underweight and 41 were >5% overweight. The CD34+ cell dose (10(6)/kg) was 1.4-11.8 (median 5) by IBW and 1.2-9.3 (median 4.5) by ABW. The CD3+ cell dose (10(8)/kg) was 0.9-14.9 (median 3) by IBW and 0.7-19.7 (median 2.7) by ABW. While CD34+ and CD3+ cell doses based upon IBW were found to affect transplant-related mortality, and disease-free and overall survival significantly, those based on ABW were either not predictive of outcome or the differences were of borderline significance. We suggest using IBW rather than ABW to calculate cell doses for HSCT; for statistical analyses and for clinical practice if a specific cell dose is being targeted.

Use of total leukocyte and platelet counts to guide stem cell apheresis in healthy allogeneic donors treated with G-CSF.

Healthy stem cell donors start leukapheresis 4-5 days after starting G-CSF based on the peripheral blood CD34+ cell count (PBCD34). Data from 137 harvests (68 donors) were analyzed to determine correlation between pre-apheresis leukocytes (11.0-94.8x10(9)/l; median 38.8) and platelets (49-374x10(9)/l; median 180), and PBCD34 (3-276/microl; median 40). PBCD34 correlated positively with leukocytes (r=0.48; P<0.0001) and platelets (r=0.40; P<0.0001). When pre-apheresis leukocytes were >or=25 and platelets were >or=100, PBCD34 and CD34+ collection were 5-276/microl (median 57) and 0.5-27.6x10(6)/kg (median 4.7), respectively; significantly higher than PBCD34 of 3-74/microl (median 17) and CD34+ collection of 0.2-8.9 x 10(6)/kg (median 2.2) when leukocytes were <25 and/or platelets were <100. With leukocytes >or=25 and platelets >or=100, PBCD34 was low (<20/microl) 8% of the time, compared to 57% of the time with leukocytes <25 and/or platelets <100 (P<0.0001). Our data suggest that it is not always necessary to measure PBCD34 to guide leukapheresis in healthy donors because pre-apheresis leukocytes and platelets >or=25 and >or=100, respectively, are associated with excellent mobilization. When blood counts do not meet these criteria, PBCD34 should be determined prior to initiation of apheresis.

Can the stem cell mobilization technique influence CD34+ cell collection efficiency of leukapheresis procedures in patients with hematologic malignancies?

A total of 415 leukaphereses in 201 patients stimulated with growth factor (GF; n = 119) or chemotherapy-GF (n = 296) were studied to determine CD34+ cell collection efficiency (CE). The pre-apheresis leukocyte count was 1-93 x 10(9)/l (median 20), and peripheral blood CD34 count (PBCD34) was 1-1104/microl (median 19). The total number of CD34+ cells collected was 4-6531 x 10(6) (median 151); corresponding to 0.1-111.4 x 10(6) (median 2.3) per kg. There was strong correlation between PBCD34 and the number of CD34+ cells collected (r = 0.9; P < 0.0001). CE was 7-145% (median 46). On multiple regression analysis, a higher leukocyte count (P < 0.0001) was the most important predictor of lower CE. CE with leukocytes < 20 was 7-145% (median 53%) compared to 10-132% (median 40%) with leukocyte > or = 20 (P < 0.0001). In all, 61% of the apheresis procedures performed after chemotherapy-GF occurred when leukocytes were < 20 compared to 21% of those performed after GF alone (P < 0.0001). We conclude that mobilizing patients with the combination of chemotherapy and GF rather than GF alone leads to leukapheresis being performed when the leukocyte count is low -- in a range that results in optimum CD34+ cell CE. Autologous stem cells should be mobilized with chemotherapy-GF rather than GF alone whenever possible.

Rust and corrosion in hematopoietic stem cell transplantation: the problem of iron and oxidative stress.

Iron overload is a common acute and long-term event associated with autologous and allogeneic hematopoietic stem cell transplantation (HSCT). In a state of iron excess, free iron becomes available to catalyze the conversion of reactive oxygen species (ROS) intermediates such as superoxide anion (O2*-) and hydrogen peroxide (H2O2) to highly toxic free radicals such as hydroxyl radical (OH*). ROS may help to promote chronic liver disease, sinusoidal obstruction syndrome, idiopathic pneumonia syndrome and bacterial, fungal and other opportunistic infections. Phlebotomy has been effectively and safely used to deplete excess iron stores post-HSCT in thalassemic and other iron-overloaded patients. Intracellular iron levels may also be decreased through pharmacologic chelating agents, while antioxidants such as N-acetylcysteine, glutamine (glutathione precursor) and captopril have been shown to replenish glutathione redox potential and scavenge free radicals. A better understanding of the mechanisms involved in the iron-generated pro-oxidant state associated with HSCT will likely lead to reduced toxicity and improved patient outcomes.