Long-term outcome of a pediatric-inspired regimen used for adults aged 18-50 years with newly diagnosed acute lymphoblastic leukemia.

On the basis of the data suggesting that adolescents and young adult patients with acute lymphoblastic leukemia (ALL) have improved outcomes when treated on pediatric protocols, we assessed the feasibility of treating adult patients aged 18-50 years with ALL with the DFCI Pediatric ALL Consortium regimen utilizing a 30-week course of pharmacokinetically dose-adjusted E. coli L-asparaginase during consolidation. Between 2002 and 2008, 92 eligible patients aged 18-50 years were enrolled at 13 participating centers. Seventy-eight patients (85%) achieved a complete remission (CR) after 1 month of intensive induction therapy. With a median follow-up of 4.5 years, the 4-year disease-free survival (DFS) for the patients achieving a CR was 69% (95% confidence interval (CI) 56-78%) and the 4-year overall survival (OS) for all eligible patients was 67% (95% CI 56-76%). The 4-year DFS for the 64 patients who achieved a CR and were Philadelphia chromosome negative (Ph-) was 71% (95% CI 58-81%), and for all 74 Ph- patients the 4-year OS was 70% (95% CI 58-79%). We conclude that a pediatric-like treatment strategy for young adults with de novo ALL is feasible, associated with tolerable toxicity, and results in improved outcomes compared with historical regimens in young adult patients with ALL.

Patient preferences for stopping tyrosine kinase inhibitors in chronic myeloid leukemia.

BACKGROUND: We used an interview-assisted survey of patients with chronic myeloid leukemia (cml) at a single tertiary care centre to explore patient reactions to and preferences for, and the risk-acceptability of, stopping tyrosine kinase inhibitor (tki) treatment. METHODS: The study included patients with confirmed cml currently being treated with a tki. The survey was conducted by structured interview using a standard form. Patient preferences were explored in a case-based scenario using 0%-100% visual analog scales and 5-point Likert scales. Data were analyzed using proportions for dichotomous variables and medians and interquartile ranges for continuous variables. RESULTS: Of 63 patients approached, 56 completed the survey. Participant responses suggest that the idea of stopping tki use is appealing to many patients if there is a chance of long-term stable disease and a high probability of response upon restarting a tki. Participants were more likely to stop their tki as the risk of relapse decreased. Participants reported loss of disease control and failure of disease to respond to treatment as important concerns if they chose to stop their tki. CONCLUSIONS: Given the current 60% estimated rate of relapse after discontinuation of tki therapy, most patients with cml chose to continue with tki. However, at the lower relapse rates reported with second-generation tkis, participants were more undecided, demonstrating a basic understanding of risk. Contrary to our hypothesis, neither compliance nor occurrence of side effects significantly affected patient willingness to stop their tki.

A phase I study of tipifarnib combined with conventional induction and consolidation therapy for previously untreated patients with acute myeloid leukemia aged 60 years and over.

Patients aged 60 years and over with previously untreated acute myeloid leukemia were enrolled in a Phase I study combining tipifarnib with standard induction therapy. The regimen consisted of cytarabine 100 mg/m(2)/day continuous intravenous (i.v.) infusion on days 1-7, daunorubicin 60 mg/m(2)/day i.v. push x 3 on days 6-8 and tipifarnib twice daily on days 6-15. Tipifarnib was escalated over four dose levels (200, 300, 400 and 600 mg). Patients achieving complete response (CR) were eligible to receive one consolidation using the same regimen. The following dose-limiting toxicities (DLTs) were identified during induction: dose level I: 2/6 (hyperbilirubinemia, respiratory arrest), level II: 0/3, level III: 0/3 and level IV: 4/10 (one each of diarrhea, neutropenic enterocolitis, arrhythmia and delayed hematologic recovery post-consolidation). There were no DLTs due to delayed hematologic recovery post-induction. Of 22 evaluable patients, there were 10 CR, 2 morphologic leukemia-free state (MLFS), 2 partial remission (PR) and 8 non-responders. Of seven patients with adverse risk cytogenetics, there were four CR/MLFS and one PR. In summary, this regimen was well tolerated and the maximum tolerated dose was not reached, although somewhat more severe gastrointestinal toxicity was seen at dose level IV. Tipifarnib 600 mg b.i.d. is considered the recommended dose for further study using this regimen.

Optimising parameters for peripheral blood leukapheresis after r-metHuG-CSF (filgrastim) and r-metHuSCF (ancestim) in patients with multiple myeloma: a temporal analysis of CD34(+) absolute counts and subsets.

Patients (n = 69) with multiple myeloma undergoing peripheral blood stem cell collection (PBSC) were treated with cyclophosphamide and a combination of recombinant methionyl human granulocyte colony-stimulating factor (r-metHuG-CSF, filgrastim) and recombinant methionyl human stem cell factor (r-metHuSCF, ancestim). The objectives of this study were to determine: (1) The proportion of patients reaching a target yield of >or=5 x 10(6) CD34(+) cells/kg in one or two successive large-volume (20 liter) leukapheresis procedures; (2) the optimal collection time for leukapheresis; (3) mobilization kinetics of CD34(+) subsets in response to G-CSF/SCF. All patients were mobilized with cyclophosphamide (2.5 g/m(2)) on day 0 followed by filgrastim (10 microg/kg ) plus ancestim (20 microg/kg) commencing day 1 and continuing to day 11 or 12. Of the 65 evaluable patients, 57 were considered not heavily pretreated and 96.5% obtained a target of >or=5 x 10(6)/kg in one collection. The median CD34(+) cells/kg was 39.5 x 10(6) (range: 5.2-221.2 x 10(6)). Subset analysis demonstrated the number of CD38(-), CD33(-), and CD133(+) peaked at day 11; and CD34(+), CD90(+) cells peaked at day 10. The optimum day for leukapheresis was determined to be day 11. The median absolute peripheral blood CD34(+) cell numbers on day 11 was 665 x 10(6)/l (range: 76-1481 x 10(6)/l). Eight of the 10 heavily pretreated patients were evaluable: three achieved the target dose in one leukapheresis (37.5%) and three (37.5%) achieved the target dose with two leukaphereses. Use of this mobilization strategy allowed the collection of high numbers of CD34(+) cells and early progenitors and the ability to predictably schedule leukapheresis.

Number of viable CD34(+) cells reinfused predicts engraftment in autologous hematopoietic stem cell transplantation.

Reduced CD34(+) cell viability due to cryopreservation has unknown effects on subsequent hematopoietic engraftment in autologous transplantation. Thirty-six consecutive autologous peripheral stem cell collections were analyzed for absolute viable CD34(+) cell numbers at the time of stem cell collection and prior to re-infusion. Viable CD34(+) cells were enumerated using single platform flow cytometry and the molecular exclusion dye 7-amino actinomycin D. The median number of viable CD34(+) cells was 3.6 x 10(6)/kg at the time of harvest and 2.0 x 10(6)/kg after thawing. When viable CD34(+)cells enumerated after thawing were <2.0, 2.0-5.0, or >5.0 x 10(6)/kg, the median time to platelet engraftment was 17, 12 and 10 days, respectively (P < 0.05 for comparison of the group with <2.0 x 10(6)/kg and the other two groups), and the median time to neutrophil engraftment was 13, 14 and 12 days, respectively (P = NS). A minimum of 2.0 x 10(6) CD34(+) cells/kg was harvested in 33 of 36 patients (92%) but only 19 of 36 (52%) patients met this threshold at the time of reinfusion. The reduced numbers of viable CD34(+) cells measured prior to re-infusion is associated with time to platelet engraftment and may be useful in monitoring stem cell loss during processing and identifying patients at risk of graft failure.

Characterization of chemokine receptors expressed in primitive blood cells during human hematopoietic ontogeny.

Chemokines are capable of regulating a variety of fundamental processes of hematopoietic cells that include proliferation, differentiation, and migration. To evaluate potential chemokine signaling pathways important to the regulation of primitive human hematopoietic cells, we examined chemokine receptor expression of highly purified subpopulations of uncommitted human blood cells. CXCR1-, CXCR2-, CXCR4-, and CCR5-expressing cells were detected by flow cytometry among human blood subsets depleted of lineage-restricted cells (Lin(-)) derived from adult bone marrow, mobilized peripheral blood, cord blood (CB), and circulating fetal blood. Although these chemokine receptors could be detected on Lin(-) cells throughout human development, only CXCR4 could be detected in CD34(-)CD38(-)Lin(-) and CD34(+)CD38(-)Lin(-) subfractions enriched for stem cell function, suggesting that independent of ontogeny, CXCR4-mediated signals are critical to primitive hematopoiesis. Distinct to other stages of human hematopoietic development, primitive CB cells expressed higher levels of CXCR1, CXCR2, CCR5, and CXCR4 on both CD34(-)CD38(-)Lin(-) and CD34(+)CD38(-)Lin(-) subsets. Isolation of these fractions revealed expression of additional chemokine receptors CCR7, CCR8, and Bonzo (STRL133), whereas BOB (GPR15) could not be detected. Our study illustrates that rare uncommitted hematopoietic cells express chemokine receptors not previously associated with primitive human blood cells. Based on these results, we suggest that signaling pathways mediated by chemokine receptors identified here may play a fundamental role in hematopoietic stem cell regulation and provide alternative receptor targets for retroviral pseudotyping for genetic modification of repopulating cells.

Acquired factor VIII inhibitor in a patient with chronic myelogenous leukemia receiving interferon-alfa therapy.

OBJECTIVE: To report a case of an acquired factor VIII inhibitor associated with the use of interferon-alfa. CASE SUMMARY: A 58-year-old white man with newly diagnosed chronic myelogenous leukemia (CML) was initially treated with hydroxyurea. Interferon-alfa therapy was started six weeks later in order to enhance the response, with gradual reduction and eventual discontinuation of hydroxyurea. Interferon-alfa was continued for one year. Following bone marrow aspiration at one year, the patient developed significant bleeding and bruising at the site of extraction. His hemoglobin decreased from 11.3 to 9.3 g/dL and his activated partial thromboplastin time was elevated at 72 seconds. The factor VIII concentration was 0.02 units/mL; factor VIII inhibitor concentration was 58 Bethesda units. A diagnosis of an acquired factor VIII inhibitor was made, and the patient was treated with activated factor VII concentrates and prednisone. Interferon-alfa was discontinued, and the inhibitor subsequently disappeared over the next six weeks. The patient did not have any further bleeding problems. DISCUSSION: Acquired factor VIII inhibitors other than in patients with hemophilia are rare. To date, there are no reported cases of factor VIII inhibitors associated with CML. Moreover, the temporal association with interferon-alfa administration suggests a causal relationship. There are only two previous case reports suggesting interferon-alfa as a cause of factor VIII inhibitors. CONCLUSIONS: Induction of factor VIII inhibitors is a serious potential complication of therapy with interferon-alfa. We suggest that a diagnosis of an acquired factor VIII inhibitor be considered in patients who experience unexplained bleeding with interferon-alfa therapy.

Prevention of bladder tumor formation in mice by a novel bone marrow-derived factor, reptimed.

BACKGROUND: Reptimed is a novel, species-conserved, bone marrow-derived molecule which possesses anti-neoplastic activity. Previously, we established an orthotopic murine bladder tumor (MBT-2) model and reported accurate documentation of the presence and the extent of intravesical involvement of bladder tumor implants using magnetic resonance imaging (MRI) (1). Herein, we investigated the activity of exogenously administered Reptimed in the MBT-2 model. MATERIALS AND METHODS: Intravesicular and intraperitoneal administration of Reptimed concurrently with and following transurethral tumor cell implantation was performed and MBT-2 tumor response was assessed at several time points post tumor implant. RESULTS: Serial MRI scans of Reptimed-treated mice at days 14 to 33 post tumor transplant revealed significant inhibition of bladder tumor growth with no significant tumor growth observed by MRI on day 33 post-implant. The corresponding histological examination of the whole mount bladder sections revealed similar inhibitory effects of Reptimed with respect to the topography and depth of intravesical tumor involvement. In contrast, control, untreated bladders revealed extensive exophytic tumors with deeply invasive transitional cell carcinoma. CONCLUSIONS: These studies demonstrate the anti-tumor effect of Reptimed and highlight its importance as a potential therapy for cancer.

Suppression of myelopoiesis and myeloid leukemia cell line proliferation by a novel bone marrow-derived factor, reptimed.

Bone marrow is the major site of hematopoiesis in the adult mammal. Bone marrow contains a highly organized microenvironment for the support of hematopoietic stem and progenitor cells, including the production of growth factors. Bone marrow cells also produce negative regulatory factors which may regulate hematopoiesis and inflammatory responses. In this paper we describe Reptimed, a unique bone marrow-derived factor with inhibitory activity for myelopoiesis and in vitro growth of myeloid cell lines. Reptimed was partially purified from bone marrow supernatants using a combination of solid-phase extraction and size exclusion chromatography. Reptimed is < 1000 Da MW and is water soluble. Reptimed inhibited growth of granulocyte-macrophage and macrophage colonies as well as proliferation of several myeloid leukemia cell lines. Reptimed may be part of a hemoregulatory circuit.

In utero engraftment of fully H-2-incompatible versus congenic adult bone marrow transferred into nonanemic or anemic murine fetal recipients.

We have established a murine in utero bone marrow transplantation model system and have investigated the effects of donor strain differences, cell dose, and the number of injections on murine fetal survival and engraftment rates. In a series of experiments, 1221 nonanemic C57BL/6 fetuses were injected transplacentally on day 11 of gestation with 10(6) non-T-depleted adult bone marrow cells (BMC) from C57BL/6-CAST (congenic), BALB/c and DBA/1 (allogeneic) strains without recipient conditioning. Overall fetal survival was 45%, with a 4% engraftment rate in 475 evaluable day 5 newborns. Engrafted newborns initially had up to 75-100% donor peripheral blood cell engraftment, particularly with DBA/1 BMC. Surprisingly, a significantly (P < 0.05) higher incidence of engraftment was observed using allogeneic (5.2%) as compared with congenic donors (0.7%). However, engraftment in all groups was transient since engrafted recipients studied > or = 6 weeks post-natally had nondetectable levels of donor cells. In contrast, engraftment of congeneic marrow into anemic, stem cell-defective Wv/Wv recipients lead to a higher incidence (40%) of engraftment that persisted for > or = 6 weeks, increasing in the level of engraftment over time. Additional studies were performed in an attempt to further increase the incidence and permanence of engraftment. Neither doubling the cell dose nor doubling the number of injections improved engraftment rates in recipients of allogeneic bone marrow. Similarly, pretreatment of congeneic donors with 5-fluorouracil 4 days prior to harvesting marrow was not effective in increasing engraftment. Despite the inability to detect donor cells > or = 6 weeks postallografting, 2 of 10 evaluable recipients engrafted with DBA/1 BMC had specific and permanent (> 6 months observation time) tolerance to the donor skin graft with an intact capacity to reject third-party grafts. Thus short-term engraftment of allogeneic adult marrow stem cells can be successfully accomplished in a proportion of nonanemic fetal recipients. Engraftment of allogeneic donor cells can also lead to induction of a degree of tolerance in a proportion of recipients at maturity. These data form the basis of future studies directed toward understanding the mechanisms involved in in utero and postnatal marrow graft resistance, which will ultimately lead to designing strategies that will further enhance the permanence of engraftment with the use of adult marrow cells.

Treatment of idiopathic thrombocytopenic purpura with ascorbate.

The treatment of idiopathic thrombocytopenic purpura (ITP) includes corticosteroids, danazol, splenectomy and various immunosuppressives. Treatment can be difficult for those patients refractory to these modalities and/or those patients intolerant of the secondary effects. In this paper we report on the use of ascorbate in the treatment of ITP and its successful use in seven of 11 patients studied. We found that therapy with ascorbate appeared to improve the platelet count and the intravascular survival of platelets. Because of excellent patient compliance and its lack of toxicity, it may be an alternative for the treatment of ITP. The exact role of ascorbate in the treatment of ITP, as well as its mechanism of action, await further study.

[Immune regulation of hematopoiesis]. / Immunregulation der Hämatopoese.

Effective hematopoiesis is a multistep phenomenon. It consists in the presence of pluripotent hematopoietic stem cells (HSC), their proliferation and self-maintenance, their differentiation into various committed lineages of specific progenitors, their orderly maturation into functional cells that are released into the circulation in an orderly fashion in response to the body's demand. Increasing numbers of hematopoietic factors are being purified to homogeneity and/or cloned. The availability of sufficient quantities of these regulators promises a new area for research into the physiology and pathophysiology of the hematopoietic system. The purpose of this overview is to consider some newly-developed concepts in the field of hematopoiesis, with regard to regulatory control mechanisms and cellular interactions.