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Biomedical subjects

Martin S Tallman

Publications and source records attributed to Martin S Tallman.

At least 37 records · Page 2Linked to original sources
PubMed2006

2-CdA in the treatment of hairy cell leukemia: a review of long-term follow-up.

Hairy cell leukemia is a rare, indolent, chronic lymphoproliferative disorder characterized by the proliferation of a malignant B-cell clone with irregular cytoplasmic projections. Treatment with purine analogs such as 2-chlorodeoxyadenosine (2-CdA) is associated with excellent remission rates and long-term survival. Although the majority of patients achieve a complete remission (CR), most have minimal residual disease detected by sensitive methods. Despite the long term disease-free survival, approximately 36% of patients relapse and many require further therapy. Repeat administration of 2-CdA is very effective in achieving a second CR. Recently, new agents such rituximab and BL22 were shown to be effective in the treatment of relapsed and refractory disease.

Cladribine↗
PubMed2006

Activation of mammalian target of rapamycin and the p70 S6 kinase by arsenic trioxide in BCR-ABL-expressing cells.

Arsenic trioxide (As(2)O(3)) exhibits important antitumor activities in vitro and in vivo, but the precise mechanisms by which it induces its effects are not known. We provide evidence that during treatment of BCR-ABL-expressing cells with As(2)O(3), there is activation of a cellular pathway involving the p70 S6 kinase (p70S6K). Our data show that p70S6K is rapidly phosphorylated on Thr(421) and Ser(424) and is activated in an As(2)O(3)-inducible manner. The mammalian target of rapamycin (mTOR) is also phosphorylated/activated in an As(2)O(3)-inducible manner, and its activity is required for downstream engagement of p70S6K. p70S6K subsequently phosphorylates the S6 ribosomal protein on Ser(235)/Ser(236) and Ser(240)/Ser(244) to promote initiation of mRNA translation. Treatment of chronic myelogenous leukemia-derived cell lines with As(2)O(3) also results in phosphorylation of the 4E-BP1 repressor of mRNA translation on Thr(37)/Thr(46) and Thr(70), sites required for its deactivation and its dissociation from the eukaryotic initiation factor 4E complex to allow cap-dependent mRNA translation. In studies to determine the functional relevance of this pathway, we found that inhibition of mTOR and downstream cascades enhances induction of apoptosis by As(2)O(3). Consistent with this, the mTOR inhibitor rapamycin strongly potentiated As(2)O(3)-mediated suppression of primitive leukemic progenitors from the bone marrow of chronic myelogenous leukemia patients. Altogether, our data show that the mTOR/p70S6K pathway is activated in a negative feedback regulatory manner in response to As(2)O(3) in BCR-ABL-transformed cells and plays a key regulatory role in the induction of anti-leukemic responses.

Antineoplastic Agents↗
PubMed2006

Immunophenotypic variations in hairy cell leukemia.

Hairy cell leukemia (HCL) exhibits a characteristic immunophenotypic profile that is strongly positive for pan-B-cell markers; positive for CD103, CD11c. and CD25; and usually negative for CD5, CD10, and CD23. We evaluated 35 HCL cases and identified atypical immunophenotypes in 12 cases (34%), including CD103- in 2 (6%), CD25- in 1 (3%), CD10+ in 5 (14%), and CD23+ in 6 (17%) cases. Among these cases one was CD103-/CD10+ and one was CD10+/CD23+. All available specimens from the 12 cases were reviewed and showed morphologic features characteristic for HCL. The initial clinical information was reviewed and showed no significant differences with that reported for typical HCL. Of the 12 cases, 11 patients received purine analogue therapy and achieved complete remissions. Our study indicates that it is not uncommon for HCL to display an unusual immunophenotype, including negativity for CD103 or CD25. Recognizing the variability of immunophenotype and correlating with morphologic and clinical features are essential for establishing an accurate diagnosis of HCL.

Adult↗
PubMed2006

Monoclonal antibodies for the treatment of acute myeloid leukemia.

Currently, patients with acute myeloid leukemia (AML) are treated with cytotoxic chemotherapy and hematopoietic stem cell transplantation (HSCT). With this approach, the majority of patients still die of their disease because of both treatment-related mortality and relapse. Recently, monoclonal antibodies and immunoconjugates have been developed which potentially may increase the efficacy of treatment and decrease morbidity and mortality by specifically targeting the malignant cell. Unconjugated monoclonal antibodies have shown only moderate activity. A second, more effective, approach involves antibody conjugation with radioactive particles or chemotherapeutic agents, such as, immunotoxins, targeted delivery of cell killing. The antigens CD33, CD45, and CD66, are three antigens to which monoclonal antibodies have been directed. Most experience has been with gemtuzumab ozogamicin (Mylotarg) which is an immunoconjugate of an anti-CD33 antibody chemically linked to a potent cytotoxic agent, calicheamicin. Gemtuzumab ozogamicin appears to be particularly active in patients with acute promyelocytic leukemia, possibly related to the high expression of the CD33 antigen on the cell surface. Although gemtuzumab ozogamicin has activity as a single agent, the most promising result may be seen when this agent is combined with conventional cytotoxic chemotherapy. Preliminary studies have suggested a high complete remission rate and randomized clinical trials are underway. A unique potential toxicity has been identified, namely venoocclusive disease or sinusoidal obstructive syndrome which may be problematic among patients who subsequently undergo HSCT. An additional strategy includes radiolabeled monoclonal antibodies to intensify the conditioning regimen prior to HSCT. The most promising results have been obtained with radiolabeled anti-CD45 antibodies.

Antibodies, Monoclonal↗
PubMed2006

Strategies for the treatment of acute promyelocytic leukemia.

The outcome of acute promyelocytic leukemia (APL) has improved dramatically during the past 40 years. Insights into the genetic and biologic mechanisms of APL lead to the development of specific and effective therapeutic strategies. This article discusses the therapeutic interventions that transformed APL from one of the most lethal leukemias to one that is highly curable.

Antibiotics, Antineoplastic↗
PubMed2005

T-cell non-Hodgkin lymphoma.

T-cell non-Hodgkin lymphomas (NHLs) are uncommon malignancies. The current WHO/EORTC classification recognizes 9 distinct clinicopathologic peripheral T-cell NHLs. These disorders have unique characteristics and require individualized diagnostic and therapeutic strategies. Tremendous progress has been made in recent years in the understanding of the pathogenesis of these disorders. Specific chromosomal translocations and viral infections are now known to be associated with certain lymphomas. In this review, we describe their clinical and pathologic features. We also discuss the use of molecular studies in the diagnostic work-up of T-cell lymphomas. Because of the rarity of these disorders and the lack of well-designed clinical trials, the treatment of peripheral T-cell NHLs is often challenging. Additional studies are required to learn more about the biology of these diseases, which may lead to more optimal and possibly targeted therapies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Role of the p38 mitogen-activated protein kinase pathway in cytokine-mediated hematopoietic suppression in myelodysplastic syndromes.

The p38 mitogen-activated protein kinase (MAPK) pathway is activated by IFNs and other cytokines to mediate signals for important cellular functions, including transcriptional regulation and apoptosis. We examined the role of the p38 pathway in the generation of the effects of myelosuppressive cytokines on human hematopoiesis. Pharmacologic inhibition of p38 using BIX-01208 resulted in reversal of IFN-, tumor necrosis factor-alpha (TNF-alpha)-, and transforming growth factor-beta (TGF-beta)-mediated suppression of human erythroid (blast-forming unit-erythroid) and myeloid (granulocyte-macrophage colony-forming unit) colony formation, consistent with a key role for p38 in the generation of myelosuppressive signals by different cytokines. Similarly, the myelosuppressive effects of TNF-alpha and TGF-beta were reversed by small interfering RNAs targeting p38alpha expression, further establishing the requirement of this kinase in the induction of myelosuppressive responses. As TNF overproduction has been implicated in the pathophysiology of bone marrow failure states, we determined whether pharmacologic inhibition of p38 reverses the hematopoietic defects seen in bone marrows from patients with myelodysplastic syndromes (MDS) and the anemia of chronic disease. Addition of pharmacologic inhibitors of p38 on such bone marrows resulted in increased numbers of erythroid and myeloid progenitors. Similarly, inhibition of the activity of the downstream effectors of p38, MAPK activated protein kinase-2, and mitogen and stress activated kinase 1 partially restored the hematopoietic defect seen in these bone marrows. Taken altogether, our data implicate the p38 MAPK in the pathophysiology of myelodysplasias and suggest that p38 pharmacologic inhibitors may have therapeutic applications in the treatment of MDS.

Aged↗
PubMed2005

Induction therapy for adults with acute lymphoblastic leukemia: results of more than 1500 patients from the international ALL trial: MRC UKALL XII/ECOG E2993.

The international acute lymphoblastic leukemia (ALL) study was designed to prospectively define the optimal therapy for adults 60 years of age or younger with newly diagnosed ALL. All patients received identical induction therapy, and 91% achieved complete remission (CR). Patients 50 years of age or younger with a compatible sibling were assigned to undergo allogeneic transplantation; the others were randomly assigned to autologous transplantation or to consolidation/maintenance therapy for 2.5 years. Patients who did not achieve CR after induction had an overall survival rate of 5% compared with 45% for patients who achieved CR. Factors at diagnosis predictive of overall survival and disease-free survival were age (P = .001), white blood cell count less than 30 x 10(9)/L for B lineage or less than 100 x 10(9)/L for T lineage (P = .001) and immunophenotype, T lineage versus B lineage (P = .001). The data demonstrate that achieving CR with induction therapy is indispensable for long-term survival in adult patients with ALL. Furthermore, with a response rate greater than 90%, the induction regimen was highly efficacious as remission-inducing therapy. This large database has validated several previously identified independent prognostic factors in ALL, such as age, white blood cell count at presentation, cytogenetics, and immunophenotype. However, the achievement of CR within 4 weeks does not appear to be an independent prognostic factor.

Adult↗
PubMed2005

Long-term outcome of individuals with pure red cell aplasia and antierythropoietin antibodies in patients treated with recombinant epoetin: a follow-up report from the Research on Adverse Drug Events and Reports (RADAR) Project.

Since its introduction in 1988, recombinant human erythropoietin (epoetin) has been standard treatment for patients with anemia due to chronic kidney disease. From 1998 to 2004, nearly 200 epoetin-treated persons with chronic kidney disease developed antibodies to epoetin, resulting in pure red cell aplasia (PRCA). The majority of these patients received Eprex, an epoetin alfa product marketed exclusively outside the United States. Herein, we report on the long-term outcome of these individuals. For 170 chronic kidney disease patients who developed epoetin-associated PRCA and had 3 months or more follow-up information available, case reports from the Food and Drug Administration and epoetin manufacturers were reviewed for information on clinical characteristics of the patients, immunosuppressive treatments, epoetin responsiveness, and hematologic recovery. Overall, 64% of the PRCA patients received immunosuppressive therapy, including 19 who also underwent a renal transplantation. Thirty-seven percent experienced a hematologic recovery, with higher hematologic recovery rates among PRCA patients who received immunosuppressive therapy (57% vs 2%, P < .001). Among 34 patients who received epoetin after the onset of PRCA, 56% regained epoetin responsiveness. The highest rates of epoetin responsiveness were observed among persons whose antierythropoietin antibodies were undetectable when epoetin was administered (89%). Among chronic kidney disease patients with epoetin-associated PRCA, epoetin discontinuation and immunosuppressive therapy or renal transplantation is necessary for hematologic recovery. Reinitiation of epoetin therapy among individuals could be considered if antierythropoietin antibodies are undetectable.

Autoantibodies↗
PubMed2005

The Research on Adverse Drug Events and Reports (RADAR) project.

CONTEXT: In 1998, a multidisciplinary team of investigators initiated RADAR (Research on Adverse Drug events And Reports), a clinically based postmarketing surveillance program that systematically investigates and disseminates information describing serious and previously unrecognized adverse drug and device reactions (ADRs). OBJECTIVE: To describe the structure, operations, and preliminary findings from the RADAR project and related dissemination efforts by pharmaceutical suppliers and the US Food and Drug Administration (FDA). DESIGN: After identifying a serious and unexpected clinical event suitable for further investigation, RADAR collaborators postulated clinical hypotheses and derived case series and incidence estimates from physician queries, published and unpublished clinical trials, published case reports, FDA databases, and manufacturer sales figures. RESULTS: RADAR investigators identified 16 types of serious ADRs among 1699 patients, of whom 169 (10%) died as a result of the reaction. Initial cases were identified by 7 RADAR investigators, 4 collaborating physicians, 2 attorneys, and by reviewing 3 published reports. Additional sources included queries of occupational health programs and medical directors of interventional cardiology laboratories (3 types of ADRs), published manuscripts and clinical trials (11 types of ADRs), review of medical records at a RADAR site (2 types of ADRs), unpublished clinical trial reports (3 types of ADRs), and reports from attorneys, family members, or patients (4 types of ADRs). Incidence estimates, ranging from 0.4% to 33%, were derived from 5 clinical trial reports, 2 physician queries, and 2 observational databases. Laboratory support for hypotheses included identification of 3 neutralizing antibodies and 3 histopathological findings. ADR reports were disseminated as 8 revised package inserts, 7 "dear doctor" letters, and 9 peer-reviewed articles. CONCLUSION: A new, clinically based, hypothesis-driven approach to postmarketing surveillance may supplement existing regulatory surveillance systems and improve patient safety.

Adverse Drug Reaction Reporting Systems↗
PubMed2005

Drug therapy for acute myeloid leukemia.

Although improvement in outcomes has occurred in younger adults with acute myeloid leukemia (AML) during the past 4 decades, progress in older adults has been much less conspicuous, if at all. Approximately 50% to 75% of adults with AML achieve complete remission (CR) with cytarabine and an anthracycline such as daunorubicin or idarubicin or the anthracenedione mitoxantrone. However, only approximately 20% to 30% of the patients enjoy long-term disease survival. Various postremission strategies have been explored to eliminate minimal residual disease. The optimal dose, schedule, and number of cycles of postremission chemotherapy for most patients are not known. A variety of prognostic factors can predict outcome and include the karyotype of the leukemic cells and the presence of transmembrane transporter proteins, which extrude certain chemotherapy agents from the cell and confer multidrug resistance and mutations in or over expressions of specific genes such as WT1, CEBPA, BAX and the ratio of BCL2 to BAX, BAALC, EVI1, KIT, and FLT3. Most recently, insights into the molecular pathogenesis of AML have led to the development of more specific targeted agents and have ushered in an exciting new era of antileukemia therapy. Such agents include the immunoconjugate gemtuzumab ozogamicin, multidrug resistance inhibitors, farnesyl transferase inhibitors, histone deacetylase and proteosome inhibitors, antiangiogenesis agents, Fms-like tyrosine kinase 3 (FLT3) inhibitors, and apoptosis inhibitors.

Acute Disease↗
PubMed2005

Arsenic trioxide: new clinical experience with an old medication in hematologic malignancies.

Arsenic trioxide has shown great promise in the treatment of patients with relapsed or refractory acute promyelocytic leukemia (APL). In clinical trials, arsenic trioxide induces complete remission in 87% of patients and molecular remission in 83% of patients. Two-year overall and relapse-free survival estimates are 63% and 49%, respectively. Treatment with arsenic trioxide may be associated with the APL differentiation syndrome, leukocytosis, and electrocardiographic abnormalities. The expanded use of arsenic trioxide in APL for postremission therapy, in conjunction with transplantation, and in patients with newly diagnosed APL is under investigation. The multiple mechanisms of action of arsenic trioxide suggest that it may have antitumor activity in malignancies other than APL and that it may be used in combination with other agents to expand its potential use. This article reviews the clinical use of arsenic trioxide to date and discusses new therapeutic strategies evolving from its diverse biologic activities.

Antineoplastic Agents↗
PubMed2005

Differential regulation of the p70 S6 kinase pathway by interferon alpha (IFNalpha) and imatinib mesylate (STI571) in chronic myelogenous leukemia cells.

The precise mechanisms by which imatinib mesylate (STI571) and interferon alpha (IFNalpha) exhibit antileukemic effects are not known. We examined the effects of IFNs or imatinib mesylate on signaling pathways regulating initiation of mRNA translation in BCR-ABL-expressing cells. Treatment of IFN-sensitive KT-1 cells with IFNalpha resulted in phosphorylation/activation of mammalian target of rapamycin (mTOR) and downstream activation of p70 S6 kinase. The IFN-activated p70 S6 kinase was found to regulate phosphorylation of S6 ribosomal protein, which regulates translation of mRNAs with oligopyrimidine tracts in the 5'-untranslated region. In addition, IFNalpha treatment resulted in an mTOR- and/or phosphatidyl-inositol 3'(PI 3') kinase-dependent phosphorylation of 4E-BP1 repressor of mRNA translation on sites that are required for its deactivation and dissociation from the eukaryotic initiation factor-4E (eIF4E) complex. In contrast to the effects of IFNs, imatinib mesylate suppressed p70 S6 kinase activity, consistent with inhibition of BCR-ABL-mediated activation of the mTOR/p70 S6 kinase pathway. Moreover, the mTOR inhibitor rapamycin enhanced the suppressive effects of imatinib mesylate on primary leukemic granulocyte macrophage-colony-forming unit (CFU-GM) progenitors from patients with chronic myelogenous leukemia (CML). Taken altogether, our data demonstrate that IFNs and imatinib mesylate differentially regulate PI 3' kinase/mTOR-dependent signaling cascades in BCR-ABL-transformed cells, consistent with distinct effects of these agents on pathways regulating mRNA translation. They also support the concept that combined use of imatinib mesylate with mTOR inhibitors may be an appropriate future therapeutic strategy for the treatment of CML.

5' Untranslated Regions↗
PubMed2005

Treatment of hairy cell leukemia with 2-chlorodeoxyadenosine (2-CdA): long-term follow-up of the Northwestern University experience.

2-Chlorodeoxyadenosine (2-CdA), a purine analog, has become universally accepted as the agent of choice in treating hairy cell leukemia (HCL). However, few studies have reported long-term outcomes after 2-CdA treatment. Between January 1990 and June 2003, 86 consecutive patients with HCL were treated with a single 7-day course of 2-CdA by continuous infusion at a dose of 0.1 mg/kg per day. Of the 86 patients (mean age: 49 years), 67 patients (79%) achieved a complete remission (CR); 18 patients (21%) achieved a partial remission (PR); and 1 patient's response was unable to be assessed. The progression-free survival (PFS) for initial relapse after 12 years was 54%. At a median follow-up of 9.7 years (range, 0.3-13.8 years), 31 (36%) of 85 patients relapsed. There were 23 relapsed patients treated with a second cycle of 2-CdA; 2 patients were treated with alternative agents; and 6 patients were observed. Of the 23 relapsed patients retreated with 2-CdA, 12 (52%) achieved a CR and 7 (30%) patients achieved a PR (overall response rate: 83%). The overall survival (OS) rate after 12 years was 87%. There were 15 patients (17%) who developed other malignancies. Long-term follow-up of up to 14 years (median: 9.7 years) showed an excellent PFS and OS for HCL patients after 2-CdA treatment.

Adult↗
PubMed2005

Molecular target-based treatment of human cancer: summary of the 10th international conference on differentiation therapy.

The 10th International Conference on Differentiation Therapy was held between April 29 and May 3, 2004, in Shanghai, China. In the tradition of previous conferences from this series, which have been held biannually since the first meeting organized 20 years ago by Samuel Waxman and Giovanni Rossi in Sardinia, the organizers of the 10th International Conference on Differentiation Therapy aimed to gather basic and clinical cancer investigators in a setting of plenary sessions, workshops, and poster presentations to maximize the effective exchange of information and foster the establishment of collaborative interactions. Approximately 300 scientists attended the meeting with a mission to discuss targeted approaches to cancer treatment, which stem from our understanding of basic biological processes and the mechanisms of their deregulation during tumorigenesis.

Apoptosis↗
PubMed2005

Role of protein kinase C-delta (PKC-delta) in the generation of the effects of IFN-alpha in chronic myelogenous leukemia cells.

OBJECTIVE: The mechanisms by which interferon alpha (IFN-alpha) induces antileukemic responses in chronic myelogenous leukemia (CML) cells are not known. We examined whether a member of the protein kinase C (PKC) family of proteins, PKC-delta, is activated during treatment of BCR-ABL cells with IFN-alpha and participates in the induction of interferon responses. METHODS: Immunoblots and immune complex kinase assays were performed to study the phosphorylation and activation of PKC-delta in response to IFN-alpha in CML-derived cell lines. The effects of pharmacological inhibition of PKC-delta on the suppressive effects of IFN-alpha on leukemic CFU-GM progenitors from CML patients were assessed by clonogenic assays in methylcellulose. RESULTS: IFN-alpha treatment of the sensitive CML-derived KT-1 cell line resulted in phosphorylation of PKC-delta and activation of its kinase domain. Such phosphorylation/activation of PKC-delta was required for phosphorylation of Stat1 on serine 727, as inhibition of PKC-delta activity blocked the IFN-alpha-dependent serine phosphorylation of Stat1 and IFN-alpha-inducible gene transcription. IFN-alpha treatment strongly inhibited leukemic CFU-GM progenitor colony formation from bone marrow or peripheral blood of patients with CML, and such inhibition was reversed by concomitant treatment of the cells with the PKC-delta pharmacologic inhibitor rottlerin. CONCLUSION: Taken altogether, our data demonstrate that PKC-delta plays a critical role in Type I IFN signaling in BCR-ABL expressing cells, acting as a serine kinase for Stat1, to regulate transcriptional activation of interferon-regulated genes and induction of antileukemic responses.

Cell Line, Tumor↗