A polymorphism associated with STAT3 expression and response of chronic myeloid leukemia to interferon ��

Interferon α (IFN) induces variable responses in chronic myeloid leukemia (CML), with 8–30% of early chronic phase cases achieving a complete cytogenetic response. We hypothesized that polymorphic differences in genes encoding IFN signal transduction components might account for different patient responses. We studied 174 IFN-treated patients, of whom 79 achieved less than 35% Philadelphia-chromosome (Ph) positive metaphases (responders) and 95 failed to show any cytogenetic response (more than 95% Ph-positive metaphases; non-responders). We compared 17 single nucleotide polymorphisms (SNPs) at IFNAR1, IFNAR2, JAK1, TYK2, STAT1, STAT3 and STAT5a/b between the two groups and found a significant difference for rs6503691, a SNP tightly linked to STAT5a, STAT5b and STAT3 (minor allele frequency 0.16 for non-responders; 0.06 for responders, P=0.007). Levels of STAT3 mRNA correlated with rs6503691 genotype (P<0.001) as assessed by real time quantitative PCR and therefore we conclude that rs6503691 is associated with the STAT3 expression levels and response of CML patients to IFN.     

Elevated nerve growth factor and neurotrophin-3 levels in cerebrospinal fluid of children with hydrocephalus

Background

Elevated intracranial pressure (ICP) resulting from impaired drainage of cerebrospinal fluid (CSF) causes hydrocephalus with damage to the central nervous system. Clinical symptoms of elevated intracranial pressure (ICP) in infants may be difficult to diagnose, leading to delayed treatment by shunt placement. Until now, no biochemical marker of elevated ICP has been available for clinical diagnosis and monitoring. In experimental animal models, nerve growth factor (NGF) and neurotrophin-3 (NT-3) have been shown to be produced by glial cells as an adaptive response to hypoxia. We investigated whether concentrations of NGF and NT-3 are increased in the CSF of children with hydrocephalus.

Methods

NGF was determined in CSF samples collected from 42 hydrocephalic children on 65 occasions (taps or shunt placement surgery). CSF samples obtained by lumbar puncture from 22 children with suspected, but unconfirmed bacterial infection served as controls. Analysis was performed using ELISA techniques.

Results

NGF concentrations in hydrocephalic children were over 50-fold increased compared to controls (median 225 vs 4 pg/mL, p < 0.0001). NT-3 was detectable (> 1 pg/mL) in 14/31 hydrocephalus samples at 2–51 pg/mL but in none of 11 control samples (p = 0.007).

Conclusion

NGF and NT-3 concentrations are increased in children with hydrocephalus. This may represent an adaptive response of the brain to elevated ICP.     

Dasatinib induces rapid hematologic and cytogenetic responses in adult patients with Philadelphia chromosome positive acute lymphoblastic leukemia with resistance or intolerance to imatinib: interim results of a phase 2 study

Patients with Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL) have a rapid disease course and a poor prognosis. Dasatinib, a novel, oral, multitargeted kinase inhibitor of BCR-ABL and SRC family kinases, has previously induced responses in patients with imatinib-resistant or -intolerant Ph-positive ALL. We present the interim results of a phase 2 study designed to further assess the efficacy, safety, and tolerability of dasatinib 140 mg in this patient population (n = 36). With a minimum follow-up of 8 months, treatment with dasatinib resulted in substantial hematologic and cytogenetic response rates. Major hematologic responses were achieved in 42% (15/36) of patients, 67% of whom remained progression-free. Complete cytogenetic responses were attained by 58% (21/36) of patients. The presence of BCR-ABL mutations conferring imatinib resistance did not preclude a response to dasatinib. Dasatinib was also tolerable, with 6% (2/36) of patients discontinuing therapy as a result of study-drug toxicity. Most adverse events (AEs) were grade 1 or 2; febrile neutropenia was the most frequent severe AE, but this and other cytopenias were manageable with dose reduction. Dasatinib represents a safe and effective treatment option and an important therapeutic advance for patients with Ph-positive ALL. This trial was registered at www.clinicaltrials.gov as #CA180015.     

Older patients with chronic myeloid leukemia (≥65 years) profit more from higher imatinib doses than younger patients: a subanalysis of the randomized CML-Study IV

The impact of imatinib dose on response rates and survival in older patients with chronic myeloid leukemia in chronic phase has not been studied well. We analyzed data from the German CML-Study IV, a randomized five-arm treatment optimization study in newly diagnosed BCR-ABL-positive chronic myeloid leukemia in chronic phase. Patients randomized to imatinib 400 mg/day (IM400) or imatinib 800 mg/day (IM800) and stratified according to age (≥65 years vs. <65 years) were compared regarding dose, response, adverse events, rates of progression, and survival. The full 800 mg dose was given after a 6-week run-in period with imatinib 400 mg/day. The dose could then be reduced according to tolerability. A total of 828 patients were randomized to IM400 or IM800. Seven hundred eighty-four patients were evaluable (IM400, 382; IM800, 402). One hundred ten patients (29 %) on IM400 and 83 (21 %) on IM800 were ≥65 years. The median dose per day was lower for patients ≥65 years on IM800, with the highest median dose in the first year (466 mg/day for patients ≥65 years vs. 630 mg/day for patients <65 years). Older patients on IM800 achieved major molecular remission and deep molecular remission as fast as younger patients, in contrast to standard dose imatinib with which older patients achieved remissions much later than younger patients. Grades 3 and 4 adverse events were similar in both age groups. Five-year relative survival for older patients was comparable to that of younger patients. We suggest that the optimal dose for older patients is higher than 400 mg/day. ClinicalTrials.gov identifier: NCT00055874     

Definitions, methodological and statistical issues for phase 3 clinical trials in chronic myeloid leukemia: a proposal by the European LeukemiaNet

The treatment policy of chronic myeloid leukemia (CML), particularly with tyrosine kinase inhibitors, has been influenced by several recent studies that were well designed and rapidly performed, but their interpretation is of some concern because different end points and methodologies were used. To understand and compare the results of the previous and future studies and to translate their conclusion into clinical practice, there is a need for common definitions and methods for analyses of CML studies. A panel of experts was appointed by the European LeukemiaNet with the aim of developing a set of definitions and recommendations to be used in design, analyses, and reporting of phase 3 clinical trials in this disease. This paper summarizes the consensus of the panel on events and major end points of interest in CML. It also focuses on specific issues concerning the intention-to-treat principle and longitudinal data analyses in the context of long-term follow-up. The panel proposes that future clinical trials follow these recommendations.     

Enhanced ABL-inhibitor-induced MAPK-activation in T315I-BCR-ABL-expressing cells: a potential mechanism of altered leukemogenicity

Background  

Targeted treatment of chronic myelogenous leukemia using imatinib has dramatically improved patient outcome. However, residual disease can be detected in the majority of patients treated with imatinib. Compensatory activation of MAP kinases (MAPK1/2) in response to BCR-ABL-inhibitors has been reported as a potential cytokine-dependent resistance mechanism leading to the rescue of leukemic progenitor cells.