Biomedical subjects

Moshe Talpaz

Publications and source records attributed to Moshe Talpaz.

At least 19 recordsLinked to original sources

PubMed2007

Activation of a novel Bcr/Abl destruction pathway by WP1130 induces apoptosis of chronic myelogenous leukemia cells.

Imatinib mesylate (Gleevec) is effective therapy against Philadelphia chromosome-positive leukemia, but resistance develops in all phases of the disease. Bcr/Abl point mutations and other alterations reduce the kinase inhibitory activity of imatinib mesylate; thus, agents that target Bcr/Abl through unique mechanisms may be needed. Here we describe the activity of WP1130, a small molecule that specifically and rapidly down-regulates both wild-type and mutant Bcr/Abl protein without affecting bcr/abl gene expression in chronic myelogenous leukemia (CML) cells. Loss of Bcr/Abl protein correlated with the onset of apoptosis and reduced phosphorylation of Bcr/Abl substrates. WP1130 did not affect Hsp90/Hsp70 ratios within the cells and did not require the participation of the proteasomal pathway for loss of Bcr/Abl protein. WP1130 was more effective in reducing leukemic versus normal hematopoietic colony formation and strongly inhibited colony formation of cells derived from patients with T315I mutant Bcr/Abl-expressing CML in blast crisis. WP1130 suppressed the growth of K562 heterotransplanted tumors as well as both wild-type Bcr/Abl and T315I mutant Bcr/Abl-expressing BaF/3 cells transplanted into nude mice. Collectively, our results demonstrate that WP1130 reduces wild-type and T315I mutant Bcr/Abl protein levels in CML cells through a unique mechanism and may be useful in treating CML.

Animals↗

PubMed2006

New insights into the pathophysiology of chronic myeloid leukemia and imatinib resistance.

Chronic myeloid leukemia (CML) was the first human malignant disease to be linked to a single, acquired genetic abnormality. Identification of the BCR-ABL kinase fusion protein and its central role in the pathogenesis of CML provided new opportunities to develop rational molecular targeted therapies. This review provides an update on the underlying pathophysiologies of disease progression and imatinib mesylate resistance, leading to the development of new targeted tyrosine kinase inhibitors for managing CML. Imatinib, a selective inhibitor of BCR-ABL, represents a major success in the era of target-directed cancer chemotherapy. However, patients with advanced CML have been less sensitive to therapy and responses have been short. In addition, treatment resistance is an emerging problem at all disease stages. Insight into factors involved in imatinib resistance and disease progression has highlighted a role for such BCR-ABL-dependent factors as amplification and overexpression of the BCR-ABL gene and the emergence of mutant isoforms of BCR-ABL. However, BCR-ABL-independent factors, including leukemogenic pathways involving kinases other than BCR-ABL, also play a part. In light of the limitations of imatinib against these factors, newer tyrosine kinase inhibitors, including dasatinib (a multitargeted kinase inhibitor of BCR-ABL and Src family kinases) and nilotinib (AMN107, a selective BCR-ABL inhibitor), may provide promising treatment options for patients with CML.

Antineoplastic Agents↗

PubMed2006

Dasatinib (BMS-354825) is active in Philadelphia chromosome-positive chronic myelogenous leukemia after imatinib and nilotinib (AMN107) therapy failure.

Developing strategies to counteract imatinib resistance constitutes a challenge in chronic myelogenous leukemia (CML). Therapy with the tyrosine kinase inhibitors nilotinib (AMN107) and dasatinib (BMS-354825) has produced high rates of hematologic and cytogenetic response. Src kinase activation has been linked to Bcr-Abl-mediated leukemogenesis and CML progression. In addition to binding Abl kinase with less stringent conformational requirements than imatinib, dasatinib is a potent Src kinase inhibitor. In the current study, we report on 23 patients with CML (19 of them in accelerated or blastic phases) treated with dasatinib after treatment failure with both imatinib and nilotinib. More than half (13; 57%) of 23 patients responded to dasatinib: 10 (43%) had a complete hematologic response (CHR), including 7 (30%) who had a cytogenetic response (2 complete, 4 partial, and 1 minor). These results suggest that dasatinib may be active in some patients after failure with both imatinib and nilotinib.

Adult↗

PubMed2006

TRAIL-induced cleavage and inactivation of SPAK sensitizes cells to apoptosis.

Ste20-related proline-alanine-rich kinase (SPAK) has been linked to various cellular processes, including proliferation, differentiation, and ion transport regulation. Recently, we showed that SPAK mediates signaling by the TNF receptor, RELT. The presence of a caspase cleavage site in SPAK prompted us to study its involvement in apoptotic signaling induced by another TNF member, TRAIL. We show that TRAIL stimulated caspase 3-like proteases that cleaved SPAK at two distinct sites. Cleavage had little effect on the activity of SPAK but removed its substrate-binding domain. In addition, TRAIL reduced the activity of SPAK in HeLa cells in a caspase-independent manner. Thus, TRAIL inhibited SPAK by two mechanisms: activation of caspases, which removed its substrate-binding domain, and caspase-independent down-regulation of SPAK activity. Furthermore, reducing the amount of SPAK by siRNA increased the sensitivity of HeLa cells to TRAIL-induced apoptosis. Thus, TRAIL down-regulation of SPAK is an important event that enhances its apoptotic effects.

Apoptosis↗

PubMed2006

Dasatinib in imatinib-resistant Philadelphia chromosome-positive leukemias.

BACKGROUND: The BCR-ABL tyrosine kinase inhibitor imatinib is effective in Philadelphia chromosome-positive (Ph-positive) leukemias, but relapse occurs, mainly as a result of the outgrowth of leukemic subclones with imatinib-resistant BCR-ABL mutations. We evaluated dasatinib, a BCR-ABL inhibitor that targets most imatinib-resistant BCR-ABL mutations, in patients with chronic myelogenous leukemia (CML) or Ph-positive acute lymphoblastic leukemia (ALL). METHODS: Patients with various phases of CML or with Ph-positive ALL who could not tolerate or were resistant to imatinib were enrolled in a phase 1 dose-escalation study. Dasatinib (15 to 240 mg per day) was administered orally in four-week treatment cycles, once or twice daily. RESULTS: A complete hematologic response was achieved in 37 of 40 patients with chronic-phase CML, and major hematologic responses were seen in 31 of 44 patients with accelerated-phase CML, CML with blast crisis, or Ph-positive ALL. In these two phases, the rates of major cytogenetic response were 45 percent and 25 percent, respectively. Responses were maintained in 95 percent of patients with chronic-phase disease and in 82 percent of patients with accelerated-phase disease, with a median follow-up more than 12 months and 5 months, respectively. Nearly all patients with lymphoid blast crisis and Ph-positive ALL had a relapse within six months. Responses occurred among all BCR-ABL genotypes, with the exception of the T315I mutation, which confers resistance to both dasatinib and imatinib in vitro. Myelosuppression was common but not dose-limiting. CONCLUSIONS: Dasatinib induces hematologic and cytogenetic responses in patients with CML or Ph-positive ALL who cannot tolerate or are resistant to imatinib. (ClinicalTrials.gov number, NCT00064233 [ClinicalTrials.gov].).

Adolescent↗

PubMed2006

Survival benefit with imatinib mesylate versus interferon-alpha-based regimens in newly diagnosed chronic-phase chronic myelogenous leukemia.

A survival benefit for imatinib mesylate versus interferon-alpha therapy could not be demonstrated in the randomized study in newly diagnosed Philadelphia chromosome (Ph)-positive chronic-phase chronic myelogenous leukemia (CML) due to the high rate of crossover (90%) from interferon-alpha to imatinib mesylate within a year of study entry. We compared survival in 279 patients with newly diagnosed CML treated with imatinib mesylate at our institution (2000-2004) to 650 patients treated with interferon-alpha (1982-1997). The complete cytogenetic response rates were 87% with imatinib mesylate and 28% with interferon-alpha (P < .001). The estimated 3-year survival rates were 96% with imatinib mesylate and 81% with interferon-alpha (P < .01). Survival rates with imatinib mesylate were significantly better than with interferon-alpha within each of the CML prognostic risks groups. By multivariate analysis, imatinib mesylate therapy was identified as an independent favorable prognostic factor, after accounting for the impact of pretreatment factors (hazard ratio, 0.44; P < .01). By landmark analysis at 12 months, survival within each cytogenetic response category was similar with imatinib mesylate or interferon-alpha, suggesting that the survival benefit of imatinib mesylate (versus interferon-alpha in newly diagnosed CML) is through improving cytogenetic response.

Adolescent↗

PubMed2006

Staging of chronic myeloid leukemia in the imatinib era: an evaluation of the World Health Organization proposal.

BACKGROUND: Several staging classification systems, all of which were designed in the preimatinib era, are used for chronic myeloid leukemia (CML). The World Health Organization (WHO) recently proposed a new classification system that has not been validated clinically. The authors investigated the significance of the WHO classification system and compared it with the classification systems used to date in imatinib trials ("standard definition") to determine its impact in establishing the outcome of patients after therapy with imatinib. METHODS: In total, 809 patients who received imatinib for CML were classified into chronic phase (CP), accelerated phase (AP), and blast phase (BP) based on standard definitions and then were reclassified according to the new WHO classification system. Their outcomes with imatinib therapy were compared, and the value of individual components of these classification systems was determined. RESULTS: With the WHO classification, 78 patients (10%) were reclassified: 45 patients (6%) were reclassified from CP to AP, 14 patients (2%) were reclassified from AP to CP, and 19 patients (2%) were reclassified from AP to BP. The rates of complete cytogenetic response for patients in CP, AP, and BP according to the standard definition were 72%, 45%, and 8%, respectively. After these patients were reclassified according to WHO criteria, the response rates were 77% (P = 0.07), 39% (P = 0.28), and 11% (P = 0.61), respectively. The 3-year survival rates were 91%, 65%, and 10%, respectively, according to the standard classification and 95% (P = 0.05), 63% (P = 0.76), and 16% (P = 0.18), respectively, according to the WHO classification. Patients who had a blast percentage of 20-29%, which is considered CML-BP according to the WHO classification, had a significantly better response rate (21% vs. 8%; P = 0.11) and 3-year survival rate (42% vs. 10%; P = 0.0001) compared with patients who had blasts > or = 30%. CONCLUSIONS: Different classification systems had an impact on the outcome of patients, and some prognostic features had different prognostic implications in the imatinib era. The authors believe that a new, uniform staging system for CML is warranted, and they propose such a system.

Adolescent↗

PubMed2006

The TNF receptor, RELT, binds SPAK and uses it to mediate p38 and JNK activation.

Receptor expressed in lymphoid tissues (RELT) is a new member of the TNFR family with little known regarding its signaling. Typically, TNFRs engage TRAFs for activation of NF-kappaB and MAPK cascades. We found that RELT does not use the standard signaling pathways characteristic of other TNFRs. While overexpression of RELT in 293 cells induced p38 and JNK activation, it did not activate NF-kappaB. In addition, no binding of RELT to TRAF1,2,3,5, or 6 was detected. Using a yeast two-hybrid system, we identified a Ste20-related proline-alanine-rich kinase (SPAK) that binds RELT. Disruption of the SPAK binding motif, 349RFRV, in RELT inhibited RELT activation of p38 and JNK. In addition, a kinase-dead SPAK acted as an inhibitor of RELT signaling. Thus, we conclude that RELT does not rely on the canonical TRAF pathways for its function, but instead uses a kinase, SPAK, to mediate p38 and JNK activation.

Animals↗

PubMed2006

Pregnancy among patients with chronic myeloid leukemia treated with imatinib.

PURPOSE: Imatinib has potential teratogenicity in animals, but the effect of exposure to imatinib during conception and pregnancy in humans is not known. PATIENTS AND METHODS: The records of all patients with chronic myeloid leukemia (CML) treated with imatinib were reviewed. We report the experience on 19 pregnancies involving 18 patients (10 females and eight males) who conceived while receiving imatinib for the treatment of CML. RESULTS: All female patients discontinued therapy immediately on recognition of pregnancy. Three pregnancies (involving two female patients and one male patient) ended in spontaneous abortion, and one patient had an elective abortion. All other pregnancies were uneventful. Two of the 16 babies had minor abnormalities at or shortly after birth (hypospadias in one baby and rotation of small intestine in one baby) that were surgically repaired. All babies have continued normal growth and development. Among female patients who interrupted therapy, five of nine in complete hematologic remission (CHR) at the time of treatment interruption eventually lost CHR, and six experienced an increase in Philadelphia chromosome-positive metaphases. At a median of 18 months after resuming therapy with imatinib, eight patients had a cytogenetic response (complete in three patients). CONCLUSION: Although there is no evidence that a brief exposure to imatinib during conception and pregnancy adversely affects the developing fetus, most patients lose their response after treatment interruption. Patients receiving imatinib should be advised to practice adequate contraception.

Abortion, Spontaneous↗

PubMed2006

Pilot study of lonafarnib, a farnesyl transferase inhibitor, in patients with chronic myeloid leukemia in the chronic or accelerated phase that is resistant or refractory to imatinib therapy.

BACKGROUND: Lonafarnib (SCH66336) is a nonpeptidomimetic farnesyl transferase inhibitor that has demonstrated significant preclinical activity against chronic myelogenous leukemia (CML) cells and in CML animal models. METHODS: In the current study, the efficacy of lonafarnib was investigated in patients with CML in the chronic or accelerated phase that was resistant or intolerant to imatinib. Thirteen patients with CML in the chronic (n = 6 patients) or accelerated (n = 7 patients) phase were treated with lonafarnib at a dose of 200 mg orally twice daily. Ten patients had failed therapy with imatinib and 3 patients were intolerant to imatinib. The median age of the patients was 62 years (range, 38-80 yrs) and the median time from the diagnosis of CML to therapy with lonafarnib was 5 years (range, 0.3-13 yrs). In addition to imatinib mesylate, all patients had received prior therapy with interferon-alpha and seven patients had received other treatments. The median duration of therapy with lonafarnib was 8 weeks (range, 2-41 wks). RESULTS: Two patients responded. One patient in the accelerated phase of CML returned to the chronic phase, a response that lasted for 3 months. Another patient with chronic phase disease had lowering of the leukocyte count without the need for hydroxyurea and normalization of the differential count that lasted for 5 months. The most common adverse event was diarrhea, which was noted in 11 patients (84%) (Grade > or = 3 in 4 patients; 31%; toxicity was graded according to the National Cancer Institute Common Toxicity Criteria [version 2.0]). Therapy was discontinued in one patient because of diarrhea not responding to dose adjustments. CONCLUSIONS: Single-agent lonafarnib appears to have clinical activity in a small proportion of patients with CML refractory to imatinib.

Adult↗

PubMed2006

Distinct biological impact of dephosphorylation vs. downregulation of p210Bcr-Abl: implications for imatinib mesylate response and resistance.

Imatinib mesylate suppresses phosphorylation of its kinase target, Bcr-Abl. We hypothesized that loss of p210Bcr-Abl (the kinase target) may lead to imatinib mesylate resistance. We studied K562 cells [chronic myelogenous leukemia (CML) blast crisis line] and MO7E/MBA-1 cells (with MBA-1 cells representing MO7E cells stably transfected with BCR-ABL). Imatinib mesylate resistance developed when p210Bcr-Abl expression was abolished. Furthermore, K562 cells were significantly more growth suppressed after imatinib mesylate exposure than after downregulation of Bcr-Abl expression. Signaling pathways which were functional in the absence of Bcr-Abl expression (NF-kappaB and mitogen-activated protein kinase activation or the growth factor pathway) were disrupted when p210Bcr-Abl was present but dephosphorylated, suggesting that an intact, but enzymatically inactive Bcr-Abl, may interfere with critical growth/signaling pathways. Downregulation of p210Bcr-Abl may be a mechanism by which imatinib mesylate resistance emerges. Samples from three of 15 patients with imatinib mesylate-resistant CML blast crisis had undetectable levels of p210Bcr-Abl. We conclude that retention of a dephosphorylated p210Bcr-Abl has a biologic impact distinct from that of downregulation/loss of p210Bcr-Abl and, in a subset of patients, loss of the target of the kinase inhibitor may lead to imatinib mesylate resistance.

Benzamides↗

PubMed2006

Chronic myeloid leukemia: changing the treatment paradigms.

Molecular discoveries and clinical advances over the past few decades have made the treatment of chronic myeloid leukemia (CML) one of the great success stories of modern medicine. Before the 1980s, the focus was on maintaining normal white blood cell counts with agents such as hydroxyurea and busulfan. With the use of interferon, treatment strategies turned more toward cytogenetic remission. In 1998, targeted therapy was introduced to this setting with the first studies of imatinib mesylate. Since then, treatment objectives have shifted toward the attainment of molecular remission. In this review, we consider the variety of approaches to treating CML, efforts to minimize treatment failures, and possible future directions in therapy.

Antineoplastic Agents↗

PubMed2005

Adaphostin-induced oxidative stress overcomes BCR/ABL mutation-dependent and -independent imatinib resistance.

The BCR/ABL kinase has been targeted for the treatment of chronic myelogenous leukemia (CML) by imatinib mesylate. While imatinib has been extremely effective for chronic phase CML, blast crisis CML and Ph+ acute lymphoblastic leukemia (ALL) are often resistant. In particular, mutation of the T315 residue in the bcr/abl activation loop renders cells highly resistant to imatinib and to second-generation kinase inhibitors such as BMS-354825 or AMN107. Adaphostin is a tyrphostin that was originally intended to inhibit the BCR/ABL kinase by competing with its peptide substrates. Recent findings have in addition implicated reactive oxygen species (ROS) in the cytotoxic mechanism of adaphostin. In view of this unique mode of action, we examined the effects of adaphostin on numerous imatinib-resistant leukemia models, including imatinib-resistant CML and Ph+ ALL cell lines, cells harboring point mutations in BCR/ABL, and specimens from imatinib-resistant CML patients, using assays for intracellular ROS, apoptosis, and clonogenicity. Every model of imatinib resistance examined remained fully sensitive to adaphostin-induced cell death. Collectively, these data suggest that ROS generation by adaphostin overcomes even the most potent imatinib resistance in CML and Ph+ ALL.

Adamantane↗

PubMed2005

Dasatinib (BMS-354825) tyrosine kinase inhibitor suppresses invasion and induces cell cycle arrest and apoptosis of head and neck squamous cell carcinoma and non-small cell lung cancer cells.

PURPOSE: Epithelial tumors, including non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC), present clinical challenges. One potential target for systemic therapy is Src family nonreceptor tyrosine kinases, which are overexpressed in these tumors and induce pleiotropic effects, including increased proliferation, enhanced survival, stimulation of angiogenesis, and changes in motility. Dasatinib (BMS-354825), an ATP-competitive, small molecule tyrosine kinase inhibitor, suppresses the activity of these kinases at subnanomolar concentrations. Therefore, we tested the antitumor effects of this inhibitor in vitro to determine whether in vivo analyses were warranted. EXPERIMENTAL DESIGN: The antitumor effects of dasatinib on HNSCC and NSCLC cells were evaluated using assays to measure cell cycle progression, apoptosis, migration, and invasion. Western blotting was used to monitor its effects on cell signaling. RESULTS: Dasatinib inhibited migration and invasion in all cell lines and induced cell cycle arrest (blocking the G1-S transition) and apoptosis in some lines. The effects on migration and invasion correlated with the inhibition of Src and downstream mediators of adhesion [e.g., focal adhesion kinase (FAK), p130, and paxillin], and the cell cycle effects and apoptosis correlated with the induction of p27 and the dephosphorylation of Rb. Dasatinib also induced morphologic changes that were consistent with an upstream role for Src in regulating focal adhesion complexes. CONCLUSIONS: This study showed that Src inhibition in HNSCC and NSCLC has antitumor effects in vitro. This suggests that dasatinib would have therapeutic activity against these tumors. Clinical studies in these tumor types are warranted.

Adenosine Triphosphate↗

PubMed2005

Phase I evaluation of a 40-kDa branched-chain long-acting pegylated IFN-alpha-2a with and without cytarabine in patients with chronic myelogenous leukemia.

PURPOSE: Pegasys (PEG-IFN) is a modified form of recombinant human IFN-alpha-2a in which IFN-alpha is attached to a branched methoxypolyethylene glycol (PEG) moiety of large molecular weight (40 kDa). Such molecular modification results in sustained absorption after s.c. drug administration and a prolonged half-life. A phase I study of PEG-IFN was conducted in patients with chronic myelogenous leukemia (CML) who were previously treated with IFN-alpha to evaluate the effect of sustained exposure to IFN on patients with CML. EXPERIMENTAL DESIGN: Twenty-seven patients with long-term or IFN-refractory CML were enrolled in cohorts of three or six patients. PEG-IFN was given once weekly by s.c. injections starting at a dose of 270 microg/wk to a maximum dose of 630 microg/wk. Sixteen additional patients were treated with escalating doses of PEG-IFN ranging from 450 to 540 microg/wk in combination with two different schedules of low-dose cytarabine (1-beta-D-arabinofuranosylcytosine, ara-C). Serial venous blood samples were collected to evaluate the pharmacokinetic and pharmacodynamic characteristics of PEG-IFN in these patients. RESULTS: The dose-limiting toxicity (DLT) as defined by the protocol was not achieved at the highest dose tested of 630 mug/wk. With the addition of ara-C, the DLT was reached at 540 microg/wk. The safety profile was similar to that of unmodified IFNs. Of 27 patients treated with PEG-IFN, 14 (52%) achieved or maintained a complete hematologic response and three (11%) achieved a complete cytogenetic response. Among 16 patients treated with the combination of PEG-IFN and ara-C, 11 (69%) achieved or maintained complete hematologic remission and two (13%) achieved complete cytogenetic remission. The mean serum peak concentration (C(max)) of PEG-IFN increased from 9.4 to 28 ng/mL as the dose increased from 270 to 450 microg/wk, with no further increases in C(max) at higher dose levels. Serum concentration reached peak value starting about 48 hours after drug administration and was maintained at close to peak value throughout the dosing interval. The mean +/- SD area under the serum concentration-time curve (AUC) calculated after the first dose also increased from 1,022 +/- 694 to 3,343 +/- 2,728 ng hour/mL as dose was increased from 270 to 450 microg/wk, showing a dose-related increase in systemic exposure of PEG-IFN. As with C(max), the AUC did not increase at higher dose levels. The maximum induction (E(max)) of neopterin, the surrogate marker of the pharmacodynamic activity of PEG-IFN, increased from 120% to 361% over baseline values as the dose was increased from 270 to 540 microg/wk. On the once-weekly multiple dosing schedule, both the PEG-IFN and neopterin concentration seemed to reach steady state by week 5 and the steady-state values were maintained with chronic dosing over 6 months. CONCLUSION: Pegasys provided a significant advantage over standard IFN-alpha by enabling once-weekly dosing while maintaining acceptable safety, tolerability, and activity profiles. This branched 40-kDa PEG-IFN was well tolerated both as a monotherapy as well as in combination with ara-C. Demonstration of its sustained exposure, pharmacodynamic activity, hematologic response, and evidence of cytogenetic response in several patients in this limited study with either IFN-refractory or INF-intolerant patients provides a promise for further investigation in combination with new agents like imatinib.

Adult↗

PubMed2005

Significance of myelofibrosis in early chronic-phase, chronic myelogenous leukemia on imatinib mesylate therapy.

BACKGROUND: Myelofibrosis is associated historically with a poor prognosis in patients with chronic myelogenous leukemia (CML). Its significance in the recent era of effective therapy with imatinib mesylate is unknown. METHODS: The current study evaluated the significance of the degree of pretreatment myelofibrosis on response and survival with imatinib therapy in patients with newly diagnosed CML. The study group comprised 198 patients with newly diagnosed Philadelphia chromosome-positive, chronic-phase CML treated with imatinib mesylate therapy. They were analyzed for the prognostic significance of bone marrow reticulin fibrosis. RESULTS: Severe reticulin (Grade 3-4) fibrosis was observed in 75 patients (38%): Grade 3 in 46 (23%) patients and Grade 4 in 29 (15%) patients. There was a trend towards a lower incidence of a complete cytogenetic response in patients with Grade 4 reticulin fibrosis (76% vs. 89%; P = 0.07), and a significantly worse survival (estimated 3-year survival rate of 87% vs. 97%; P = 0.04). CONCLUSIONS: Although the prognostic significance of severe reticulin fibrosis in patients with newly diagnosed CML receiving imatinib therapy was better, 15% of patients with Grade 4 reticulin fibrosis still had a worse outcome.

Adolescent↗

PubMed2005

Interferon alpha therapy for patients with essential thrombocythemia: final results of a phase II study initiated in 1986.

BACKGROUND: In 1986, a Phase II trial of recombinant interferon-alpha (IFN-alpha) was initiated as therapy for patients with essential thrombocythemia (ET). METHODS: Patients were treated with subcutaneous IFN-alpha at a dose of 5 x 10(6) units/m(2) daily. In responding patients, the therapy lasted at least 3 years. RESULTS: Twenty-three patients (14 females and 9 males; median age, 41 years; age range, 20-63 years) with a median platelet count of 1350 x 10(9)/L were treated. After a median follow-up of 174 months (14.5 years), 15 of 20 evaluable patients (75%) responded, including 14 patients who achieved a complete hematologic response (CHR) (6 of them with bone marrow remission) and 1 patient who demonstrated a partial response. The median time to response was 6 months (range, 0.5-36 months), and the median response duration was 48 months (range, 5-114 months). Seven patients who achieved a CHR and were taken off therapy after they completed 3 years of maintenance therapy sustained their response for a median of 28 months. No symptoms or signs of thrombosis or hemorrhage were observed in responding patients. Eleven of 14 patients (78%) who achieved a CHR developed a recurrence, and 2 of 5 patients with recurrences who were rechallenged with IFN-alpha achieved a second response. The treatment was tolerated relatively well. CONCLUSIONS: IFN-alpha was safe and effective therapy for patients with ET, and the ability of IFN-alpha to reverse disease pathology and possibly modify the clinical course of patients with ET warrants its investigation in larger, prospective trials.

Adult↗

PubMed2005

Survival benefit with imatinib mesylate therapy in patients with accelerated-phase chronic myelogenous leukemia--comparison with historic experience.

BACKGROUND: The effect of imatinib mesylate on survival in the accelerated phase of chronic myelogenous leukemia (CML) is unknown. The objectives of this study were to update the long-term experience with imatinib in patients who had accelerated-phase CML and to compare outcomes with historic experience. METHODS: The outcomes of 176 patients who received treatment with imatinib were reviewed and compared with the outcomes of 213 historic control patients with accelerated-phase CML who received treatment with interferon-alpha or with other modalities. RESULTS: With imatinib, the complete hematologic response rate was 82% versus a rate < or = 50% for others, and the complete cytogenetic response rate was 43% versus rates of 0-6% for others. The estimated 4-year survival rates were 53% with imatinib, 42% with interferon-alpha, and 0-21% for others. A multivariate analysis of the total population of 389 patients indicated that imatinib therapy (vs. other therapies) was an independent, favorable prognostic factor for survival (P < 0.0001; hazard rate, 0.62). A subset analysis that included only patients who were treated with imatinib and interferon-alpha (276 patients) also identified imatinib as an independent favorable prognostic factor (P < 0.0001; hazard rate, 0.65). The 3-month cytogenetic response to imatinib was associated with significantly different survival outcomes (P < 0.0001). A multivariate analysis that included pretreatment characteristics and 3-month cytogenetic response among 150 patients who received imatinib and were alive at 3 months identified only 2 adverse independent prognostic factors: lack of a cytogenetic response at 3 months (P < 0.001) and anemia (hemoglobin < 10 g/dL; P = 0.003). Patients who had neither factor (41%) had an estimated 4-year survival rate of 88%; in the other patients, the 4-year survival rate was < or = 60%. This may have implications in relation to subsequent therapy, because, according to the outcomes of patients who underwent allogeneic transplantation in accelerated phase at the authors' institution and from literature reports, the estimates of 5-year survival were 25-30%. CONCLUSIONS: The current results suggest that imatinib improved survival compared with other therapies in patients with accelerated-phase CML.

Adult↗