Showing papers by "Jan A. Burger published in 2014"
TL;DR: The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or smallymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials.
Abstract: Summary Background Chemoimmunotherapy has led to improved numbers of patients achieving disease response, and longer overall survival in young patients with chronic lymphocytic leukaemia; however, its application in elderly patients has been restricted by substantial myelosuppression and infection. We aimed to assess safety and activity of ibrutinib, an orally administered covalent inhibitor of Bruton tyrosine kinase (BTK), in treatment-naive patients aged 65 years and older with chronic lymphocytic leukaemia. Methods In our open-label phase 1b/2 trial, we enrolled previously untreated patients at clinical sites in the USA. Eligible patients were aged at least 65 years, and had symptomatic chronic lymphocytic leukaemia or small lymphocytic lymphoma requiring therapy. Patients received 28 day cycles of once-daily ibrutinib 420 mg or ibrutinib 840 mg. The 840 mg dose was discontinued after enrolment had begun because comparable activity of the doses has been shown. The primary endpoint was the safety of the dose-fixed regimen in terms of frequency and severity of adverse events for all patients who received treatment. This study is registered with ClinicalTrials.gov, number NCT01105247. Findings Between May 20, 2010, and Dec 18, 2012, we enrolled 29 patients with chronic lymphocytic leukaemia and two patients with small lymphocytic lymphoma. Median age was 71 years (range 65–84), and 23 (74%) patients were at least 70 years old. Toxicity was mainly of mild-to-moderate severity (grade 1–2). 21 (68%) patients had diarrhoea (grade 1 in 14 [45%] patients, grade 2 in three [10%] patients, and grade 3 in four [13%] patients). 15 (48%) patients developed nausea (grade 1 in 12 [39%] patients and grade 2 in three [10%] patients). Ten (32%) patients developed fatigue (grade 1 in five [16%] patients, grade 2 in four [13%] patients, and grade 3 in one [3%] patient). Three (10%) patients developed grade 3 infections, although no grade 4 or 5 infections occurred. One patient developed grade 3 neutropenia, and one developed grade 4 thrombocytopenia. After a median follow-up of 22·1 months (IQR 18·4–23·2), 22 (71%) of 31 patients achieved an objective response (95% CI 52·0–85·8); four patients (13%) had a complete response, one patient (3%) had a nodular partial response, and 17 (55%) patients had a partial response. Interpretation The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or small lymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials. Funding Pharmacyclics, Leukemia and Lymphoma Society, D Warren Brown Foundation, Mr and Mrs Michael Thomas, Harry Mangurian Foundation, P50 CA140158 to Prof J C Byrd MD.
429 citations
TL;DR: The encouraging safety and activity of ibrutinib and rituximab in this population of patients with high-risk CLL merits further investigation of this combination.
Abstract: Summary Background Ibrutinib, an orally administered covalent inhibitor of Bruton's tyrosine kinase (BTK), is an effective treatment for relapsed chronic lymphocytic leukaemia (CLL). We investigated the activity and safety of the combination of ibrutinib with the monoclonal antibody rituximab in patients with high-risk CLL. Methods In this single-arm phase 2 study, we enrolled adult patients with high-risk CLL at the MD Anderson Cancer Center (Houston, TX, USA). All enrolled participants had high-risk cytogenetic abnormalities (deletion 17p, TP53 mutation, or deletion 11q) or a short progression-free survival (PFS 2 , intravenously, every week during cycle 1, then once per cycle until cycle 6), followed by continuous daily single-agent ibrutinib 420 mg until disease progression or until toxicities or complications precluded further treatment. The primary endpoint was progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov number NCT01520519, and is no longer accruing patients. Findings Between Feb 28, 2012, and Sept 11, 2012, we enrolled 40 patients with CLL with high-risk disease features, 20 of whom had deletion 17p (del[17p]) or TP53 mutations (16 previously treated, four untreated), 13 had relapsed CLL with deletion 11q (del[11q]), and seven a PFS less than 36 months after first-line chemoimmunotherapy. 18-month PFS in all patients was 78·0% (95% CI 60·6–88·5), whereas in those with a del(17p) or TP53 mutation it was 72·4% (45·6–87·6) Toxicity was mainly mild to moderate in severity (grade 1–2). Diarrhoea occurred in ten (25%) patients (grade 1 in nine patients and grade 2 in one), bleeding events in 14 (33%) patients (eight grade 1 and five grade 2), nausea or vomiting in 15 patients (38%) (ten grade 1 and five grade 2), and fatigue in seven (18%) patients (four grade 1 and three grade 2). Five patients (13%) had grade 3 infections (two lung infections, one upper respiratory tract infection, one sepsis, and one mucositis), and no grade 4 or 5 infections occurred. One patient had grade 4 neutropenia. Interpretation The encouraging safety and activity of ibrutinib and rituximab in this population of patients with high-risk CLL merits further investigation of this combination. Funding Pharmacyclics Inc, Cancer Prevention and Research Institute of Texas, Leukemia and Lymphoma Society, National Cancer Institute, MD Anderson Cancer Center.
333 citations
TL;DR: The cellular and molecular interactions between B cell lymphoma/leukemia cells and their microenvironment, and the therapeutic targets that are emerging, focusing on small molecule inhibitors that are targeting B cell receptor-associated kinases SYK, BTK, and PI3Ks, as well as on immunomodulatory agents and T cell mediated therapies are summarized.
261 citations
TL;DR: It is found that NOX-A12 effectively inhibited CXCL12-induced chemotaxis of CLL cells and increased CLL migration underneath a confluent layer of BM stromal cells (BMSCs) due to interference with the CxCL12 gradient established by BMSCs.
179 citations
TL;DR: In this analysis of approximately 3,000 patients, CD49d emerged as the strongest flow cytometry-based predictor of OS and TFS in CLL.
Abstract: Purpose Although CD49d is an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL), definitive validation evidence is lacking. A worldwide multicenter analysis was performed using published and unpublished CLL series to evaluate the impact of CD49d as an overall (OS) and treatment-free survival (TFS) predictor. Patients and Methods A training/validation strategy was chosen to find the optimal CD49d cutoff. The hazard ratio (HR) for death and treatment imposed by CD49d was estimated by pooled analysis of 2,972 CLLs; Cox analysis stratified by center and stage was used to adjust for confounding variables. The importance of CD49d over other flow cytometry–based prognosticators (eg, CD38, ZAP-70) was ranked by recursive partitioning. Results Patients with ≥ 30% of neoplastic cells expressing CD49d were considered CD49d+. Decrease in OS at 5 and 10 years among CD49d+ patients was 7% and 23% (decrease in TFS, 26% and 25%, respectively). Pooled HR of CD49d for OS was 2.5 (2.3 for TFS) in univariate...
162 citations
TL;DR: Early MRD eradication may be a desirable goal, prompting consideration of early discontinuation of treatment, and MRD-negative patients had comparable PFS and OS, independent of the number of courses received or interim staging.
135 citations
TL;DR: The clinical advances with BTK inhibitor therapy are discussed, as well as its pathophysiological basis, and perspectives for future use of BTK inhibitors are outlined.
Abstract: BTK is a cytoplasmic, non-receptor tyrosine kinase that transmits signals from a variety of cell-surface molecules, including the B-cell receptor (BCR) and tissue homing receptors Genetic BTK deletion causes B-cell immunodeficiency in humans and mice, making this kinase an attractive therapeutic target for B-cell disorders The BTK inhibitor ibrutinib (PCI-32765, brand name: Imbruvica) demonstrated high clinical activity in B-cell malignancies, especially in patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenstrom's macroglobulinemia (WM) Therefore, ibrutinib was granted a ‘breakthrough therapy’ designation for these indications and was recently approved for the treatment of relapsed MCL by the US Food and Drug Administration Other BTK inhibitors in earlier clinical development include CC-292 (AVL-292), and ONO-4059 In CLL and MCL, ibrutinib characteristically induces redistribution of malignant B cells from tissue sites into the peripheral blood, along with rapid resolution of enlarged lymph nodes and a surge in lymphocytosis With continuous ibrutinib therapy, growth- and survival-inhibitory activities of ibrutinib result in the normalization of lymphocyte counts and remissions in a majority of patients This review discusses the clinical advances with BTK inhibitor therapy, as well as its pathophysiological basis, and outlines perspectives for future use of BTK inhibitors
104 citations
TL;DR: Ibrutinib (PCI-32765) is the most advanced BTK inhibitor in clinical testing, with ongoing phase III clinical trials in patients with chronic lymphocytic leukemia and mantle-cell lymphoma.
Abstract: Discovery of Bruton's tyrosine kinase (BTK) mutations as the cause for X-linked agammaglobulinemia was a milestone in understanding the genetic basis of primary immunodeficiencies. Since then, studies have highlighted the critical role of this enzyme in B-cell development and function, and particularly in B-cell receptor signaling. Because its deletion affects mostly B cells, BTK has become an attractive therapeutic target in autoimmune disorders and B-cell malignancies. Ibrutinib (PCI-32765) is the most advanced BTK inhibitor in clinical testing, with ongoing phase III clinical trials in patients with chronic lymphocytic leukemia and mantle-cell lymphoma. In this article, we discuss key discoveries related to BTK and clinically relevant aspects of BTK inhibitors, and we provide an outlook into clinical development and open questions regarding BTK inhibitor therapy.
94 citations
TL;DR: In this article, the authors proposed a model to predict the frequency, timing, and individual risk of developing resistance to BTKi-resistant patients, based on measured kinetic parameters of patients, and developed a roadmap for personalized prognosis and treatment management.
Abstract: The Bruton tyrosine kinase inhibitor (BTKi) ibrutinib is a new targeted therapy for patients with chronic lymphocytic leukemia (CLL). Ibrutinib is given orally on a continuous schedule and induces durable remissions in the majority of CLL patients. However, a small proportion of patients initially responds to the BTKi and then develops resistance. Estimating the frequency, timing, and individual risk of developing resistance to ibrutinib, therefore, would be valuable for long-term management of patients. Computational evolutionary models, based on measured kinetic parameters of patients, allow us to approach these questions and to develop a roadmap for personalized prognosis and treatment management. Our kinetic models predict that BTKi-resistant mutants exist before initiation of ibrutinib therapy, although they only comprise a minority of the overall tumor burden. Furthermore, we can estimate the time required for resistant cells to grow to detectable levels. We predict that this can be highly variable, depending mostly on growth and death rates of the individual CLL cell clone. For a specific patient, this time can be predicted with a high degree of certainty. Our model can thus be used to predict for how long ibrutinib can suppress the disease in individual patients. Furthermore, the model can suggest whether prior debulking of the tumor with chemo-immunotherapy can prolong progression-free survival under ibrutinib. Finally, by applying the models to data that document progression during ibrutinib therapy, we estimated that resistant mutants might have a small (<2%) mean fitness advantage in the absence of treatment, compared with sensitive cells.
87 citations
TL;DR: Central components of the CLL microenvironment are reviewed, with a particular emphasis on BCR signaling, and the most relevant clinical advances with inhibitors that target the BCR-associated spleen tyrosine kinase/SYK (fostamatinib), Bruton's tyrosINE kinase /BTK (ibrutinib), and PI3Kδ (idelalisib) are summarized.
Abstract: Interactions between malignant B lymphocytes and the tissue microenvironment play a major role in the pathogenesis of chronic lymphocytic leukemia (CLL) and other B-cell malignancies. The coexistence and coevolution of CLL cells with their tissue neighbors provided the basis for discovery of critical cellular and molecular drivers of the disease and identification of new therapeutic targets. Bone marrow stromal cells (BMSC), monocyte-derived nurselike cells (NLC), and T cells are key players in the CLL microenvironment, which activate and protect CLL cells within the tissues. CLL surface molecules, such as the B-cell antigen receptor (BCR), chemokine receptors, adhesion molecules, and TNF receptor superfamily members (e.g., CD40, BCMA, and BAFF-R) engage in cross-talk with respective tissue ligands. This cross-talk results in survival and expansion of the CLL clone, and protects CLL cells from conventional cytotoxic drugs. Inhibiting these pathways represents an alternative therapeutic strategy to more conventional chemoimmunotherapy. Here, we review central components of the CLL microenvironment, with a particular emphasis on BCR signaling, and we summarize the most relevant clinical advances with inhibitors that target the BCR-associated spleen tyrosine kinase/SYK (fostamatinib), Bruton's tyrosine kinase/BTK (ibrutinib), and PI3Kδ (idelalisib).
82 citations
TL;DR: Investigating whether BCR stimulation activates the JAK/STAT pathway in CLL cells results in activation of JAK2, which phosphorylates STAT3, and whether ruxolitinib treatment would benefit patients with CLL remains to be determined.
TL;DR: Although preclinical activity of MK-2206 can be demonstrated, this inhibitor has insufficient clinical antileukemia activity when given alone at tolerated doses, and alternative approaches to block AKT signaling should be explored.
Abstract: Purpose: Recent studies suggested that AKT activation might confer poor prognosis in acute myelogenous leukemia (AML), providing the rationale for therapeutic targeting of this signaling pathway. We, therefore, explored the preclinical and clinical anti-AML activity of an oral AKT inhibitor, MK-2206. Experimental Methods: We first studied the effects of MK-2206 in human AML cell lines and primary AML specimens in vitro . Subsequently, we conducted a phase II trial of MK-2206 (200 mg weekly) in adults requiring second salvage therapy for relapsed/refractory AML, and assessed target inhibition via reverse phase protein array (RPPA). Results: In preclinical studies, MK-2206 dose-dependently inhibited growth and induced apoptosis in AML cell lines and primary AML blasts. We then treated 19 patients with MK-2206 but, among 18 evaluable participants, observed only 1 (95% confidence interval, 0%–17%) response (complete remission with incomplete platelet count recovery), leading to early study termination. The most common grade 3/4 drug-related toxicity was a pruritic rash in 6 of 18 patients. Nevertheless, despite the use of MK-2206 at maximum tolerated doses, RPPA analyses indicated only modest decreases in Ser473 AKT (median 28%; range, 12%–45%) and limited inhibition of downstream targets. Conclusions: Although preclinical activity of MK-2206 can be demonstrated, this inhibitor has insufficient clinical antileukemia activity when given alone at tolerated doses, and alternative approaches to block AKT signaling should be explored. Clin Cancer Res; 20(8); 2226–35. ©2014 AACR .
TL;DR: The data support the clinical development of ibrutinib in patients with HCL and demonstrate uniform BTK protein expression in HCL cells, as well as inhibited also CXCL12‐induced signalling, a key pathway for bone marrow homing.
Abstract: B cell receptor (BCR) signalling plays a critical role in the progression of several B-cell malignancies, but its role in hairy cell leukaemia (HCL) is ambiguous. Bruton tyrosine kinase (BTK), a key player in BCR signalling, as well as B cell migration and adhesion, can be targeted with ibrutinib, a selective, irreversible BTK inhibitor. We analysed BTK expression and function in HCL and analysed the effects of ibrutinib on HCL cells. We demonstrated uniform BTK protein expression in HCL cells. Ibrutinib significantly inhibited HCL proliferation and cell cycle progression. Accordingly, ibrutinib also reduced HCL cell survival after BCR triggering with anti-immunoglobulins and abrogated the activation of kinases downstream of the BCR (PI3K and MAPK). Ibrutinib also inhibited BCR-dependent secretion of the chemokines CCL3 and CCL4 by HCL cells. Interestingly, ibrutinib inhibited also CXCL12-induced signalling, a key pathway for bone marrow homing. Collectively, our data support the clinical development of ibrutinib in patients with HCL.
TL;DR: New first-line strategies and agents must aim at both improving response and maintaining remission in patients with deletion 17p, particularly in the presence of complex karyotype.
Abstract: Although uncommon in treatment-naive patients with chronic lymphocytic leukemia, deletion 17p is a high-risk disease characteristic. We analyzed and reported outcomes for 63 patients with deletion 17p chronic lymphocytic leukemia who received first-line therapy at our institution; at time of first treatment, 81% had unmutated immunoglobulin heavy chain variable gene and 58% had complex karyotype. Forty-nine patients (76%) received first-line fludarabine, cyclophosphamide, rituximab-based therapy, 6 (11%) received rituximab-based and 8 (13%) received lenalidomide-based treatment. Overall, the complete plus nodular partial remission rate was 33%; on multivariable model, higher complete plus nodular partial remission rate was observed in patients with less than 50% cells positive for deletion 17p, and a higher probability of achieving at least a partial remission was observed with fludarabine, cyclophosphamide, rituximab-based treatment. After a median follow up of 33 months (range 1–89 months), the estimated median progression-free survival was 14 months (95% confidence interval 10–18) and estimated median overall survival was 63 months (95% confidence interval 43–83). In multivariable analysis, factors independently associated with longer progression-free survival were response to treatment and absence of complex karyotype. Achievement of complete plus nodular partial remission rate and mutated immunoglobulin heavy chain variable gene were independently associated with longer overall survival in multivariable model. Complex karyotype was associated with increased risk for Richter’s transformation. New first-line strategies and agents must aim at both improving response and maintaining remission in patients with deletion 17p, particularly in the presence of complex karyotype.
TL;DR: The remarkable clinical efficacy of inhibitors targeting the BCR-associated kinases Bruton's tyrosine kinase (BTK) and phosphoinositide 3-kinase delta (PI3Kδ) challenges established therapeutic paradigms and corroborates the central role of BCR signaling in CLL pathogenesis.
TL;DR: The combination of HyperCVAD regimen with dasatinib is effective in patients with relapsed Ph‐positive ALL and CML‐LB.
Abstract: Dasatinib is a second generation tyrosine kinase inhibitor, with activity in imatinib resistant Ph-positive ALL.We have treated 34 patients with relapsed Philadelphia chromosome positive acute lymphoblastic leukemia(ALL) (n519) or lymphoid blast phase of chronic myelogenous leukemia (CML-LB) (n515) with the combination of dasatinib and the hyper CVAD regimen. Prior regimens included hyper CVAD plus imatinib(n511, 4 had transplant in first CR), other combination chemotherapy (n512), monotherapy with kinase inhibitors other than dasatinib (n59), and investigational agents (n52). Pretreatment ABL mutations were noted in 10 patients. The overall response rate was 91%, with 24 patients (71%) achieving complete response(CR), and 7(21%) CR with incomplete platelet recovery (CRp). Two patients died during induction and one had progressive disease. Twenty-six patients (84%) achieved complete cytogenetic remission after one cycle of therapy. Overall, 13 patients (42%) achieved complete molecular response, and 11 patients (35%) had major molecular response (BCR-ABL/ABL<0.1%). Nine patients proceeded to allogeneic transplantation.Grades 3 and 4 toxicities included hemorrhage, pleural and pericardial effusions and infections. The median follow-up for patients with CML-LB is 37.5 months (range, 7–70 months) with a 3-year overall survival of 70%;68% remained in CR at 3 years. For ALL patients, the median follow-up is 52 months (range, 45–59 months)with a 3-year survival of 26%; 30% remain in CR at 3 years. The combination of Hyper CVAD regimen with dasatinib is effective in patients with relapsed Ph-positive ALL and CML-LB.
TL;DR: The presence of persistent cytopenia (lasting up to 9 months after the completion of therapy) should not raise concern about CLL recurrence of the development of TRMM, but should encourage surveillance for bacterial infections for an additional 9 months.
Abstract: BACKGROUND
The combination of fludarabine, cyclophosphamide, and rituximab (FCR) has produced improved response rates and a prolonged survival in patients with chronic lymphocytic leukemia (CLL). However, its therapeutic power is counterbalanced by significant hematologic toxicity. Persistent and new-onset cytopenia after the completion of FCR raise concern about disease recurrence, the development of therapy-related myeloid malignancies (TRMM), and infections.
TL;DR: Idelalisib as mentioned in this paper intercepts critical communications between B cells and the microenvironment, including B cell receptor signalling and chemokine networks, and has excellent activity in patients with chronic lymphocytic leukaemia and indolent B cell lymphomas, heralding a new era of targeted therapy for these types of cancer.
Abstract: Idelalisib, the first PI3Kδ inhibitor in clinical use, has excellent activity in patients with chronic lymphocytic leukaemia and indolent B cell lymphomas, heralding a new era of targeted therapy for these types of cancer. Idelalisib intercepts critical communications between B cells and the microenvironment, including B cell receptor signalling and chemokine networks.
TL;DR: The combination of hyper-CVAD plus nelarabine as frontline therapy in adult T-cell acute lymphoblastic leukemia and T-lymphoblastic lymphoma: MD Anderson Cancer Center experience.
Abstract: The combination of hyper-CVAD plus nelarabine as frontline therapy in adult T-cell acute lymphoblastic leukemia and T-lymphoblastic lymphoma: MD Anderson Cancer Center experience
TL;DR: AT9283 tolerability was strongly dose-dependent, with reversible myelosuppression predominating at lower doses and events such as cardiovascular toxicities manifesting at higher doses.
Abstract: Background This study sought to identify the maximum tolerated dose (MTD) of AT9283, an inhibitor of Aurora kinases A and B, in patients with relapsed or refractory leukemias. Other endpoints included pharmacokinetics, safety and tolerability, pharmacodynamics, and preliminary evidence of efficacy. Patients and Methods AT9283 was administered as a continuous 72-hour infusion every 21 days. Doses were escalated by a standard 3 + 3 design. After the MTD for the 72-hour infusion was identified, infusion duration was increased incrementally to 96 hours and 120 hours. In total, 48 patients received ≥ 1 cycle of AT9283. Median age was 61 years (range, 22-86 years); 56% were men; 75% were diagnosed with AML; and 89% had received ≥ 3 (up to 16) prior lines of therapy. Results 324 mg/m 2 /72 h AT9283 was determined to be the MTD. Dose-limiting toxicities (DLTs) were myocardial infarction, hypertension, cardiomyopathy, tumor lysis syndrome, pneumonia, and multiorgan failure. Other AT9283-related toxicities (non-DLT) included myelosuppression, predominantly leukopenia and mucositis. Bone marrow blasts decreased ≥ 38% after AT9283 treatment in approximately one-third of patients with relapsed/refractory AML; however, this effect was transient and no objective responses were achieved, despite evidence of Aurora kinase B inhibition. Two patients with accelerated-phase chronic myeloid leukemia showed evidence of benefit, manifested as a cytogenetic response in 1 case; 1 patient completed 6 cycles of treatment. Exposure to AT9283 was generally dose proportional. Conclusion AT9283 tolerability was strongly dose-dependent, with reversible myelosuppression predominating at lower doses and events such as cardiovascular toxicities manifesting at higher doses. Clinical trials with AT9283 are ongoing in alternative patient populations.
Harvard University1, University of Texas MD Anderson Cancer Center2, Vanderbilt University3, Stanford University4, Peter MacCallum Cancer Centre5, Royal North Shore Hospital6, Medical University of Vienna7, University of Rochester Medical Center8, NewYork–Presbyterian Hospital9, University of California, San Diego10, Beaumont Hospital11, Vita-Salute San Raffaele University12, University of California, Los Angeles13, Fred Hutchinson Cancer Research Center14, Ohio State University15
TL;DR: Byrd et al. as discussed by the authors reported updated efficacy results for the phase 3 RESONATETM(PCYC-1112) study of ibrutinib (ibr) vs ofatumumab (ofa), relative to genetic features and prior treatment exposure, and provide updated adverse event (AE) data.
TL;DR: Collectively, stroma-induced apoptosis resistance is mediated through signaling proteins that regulate transcriptional and translational expression and post-translational modification of Mcl-1 in CLL cells in context to bone marrow stromal microenvironment.
TL;DR: The selectivePI3K-delta inhibitor Idelalisib (Zydelig®, IDELA), in combination with rituximab (R), has been previously reported to yield a 97% ORR in treatment naive patients (pts) ≥65 years with CLL or SLL, and this report is an update on that initial cohort of study pts.
TL;DR: A large number of patients treated for R/R CLL with investigational ibrutinib-based regimens had at least one patient with a complex metaphase karyotype associated with TP53 loss, and the following were significantly associated with event-free survival (EFS): fludarabine-refractory CLL and non-del(17p).
TL;DR: This data indicates that repeat treatment with del(17p) is associated with poor outcomes using all curr...
Abstract: 7014 Background: CLL/SLL is generally very responsive to chemoimmunotherapy. However, relapses occur and resistance develops. In particular, del(17p) is associated with poor outcomes using all curr...
TL;DR: It was determined that overexpression of GM-CSFRα protected MM1 cells from dexamethasone-induced apoptosis, and GM- CSFRα knockdown induced apoptosis in CLL cells, suggesting that GM-csFRα provides a ligand-independent survival advantage.
Abstract: Here, it was determined that chronic lymphocytic leukemia (CLL) cells express the α subunit, but not the β subunit, of the granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR/CSF2R). GM-CSFRα was detected on the surface, in the cytosol, and in the nucleus of CLL cells via confocal microscopy, cell fractionation, and GM-CSFRα antibody epitope mapping. Because STAT3 is frequently activated in CLL and the GM-CSFRα promoter harbors putative STAT3 consensus binding sites, MM1 cells were transfected with truncated forms of the GM-CSFRα promoter, then stimulated with IL6 to activate STAT3 and to identify STAT3-binding sites. Chromatin immunoprecipitation (ChIP) and an electoromobility shift assay (EMSA) confirmed STAT3 occupancy to those promoter regions in both IL6-stimulated MM1 and CLL cells. Transfection of MM1 cells with STAT3-siRNA or CLL cells with STAT3-shRNA significantly downregulated GM-CSFRα mRNA and protein levels. RNA transcripts, involved in regulating cell survival pathways, and the proteins KAP1 (TRIM28) and ISG15 coimmunoprecipitated with GM-CSFRα. GM-CSFRα–bound KAP1 enhanced the transcriptional activity of STAT3, whereas GM-CSFRα-bound ISG15 inhibited the NF-κB pathway. Nevertheless, overexpression of GM-CSFRα protected MM1 cells from dexamethasone-induced apoptosis, and GM-CSFRα knockdown induced apoptosis in CLL cells, suggesting that GM-CSFRα provides a ligand-independent survival advantage. Implications: Constitutively, activation of STAT3 induces the expression of GM-CSFRα that protects CLL cells from apoptosis, suggesting that inhibition of STAT3 or GM-CSFRα may benefit patients with CLL. Mol Cancer Res; 12(9); 1267–82. ©2014 AACR.
Ohio State University1, Stanford University2, Peter MacCallum Cancer Centre3, NewYork–Presbyterian Hospital4, University of Rochester Medical Center5, University of California, San Diego6, Sarah Cannon Research Institute7, Medical University of Vienna8, University of Texas MD Anderson Cancer Center9
TL;DR: The concomitant use of anticoagulant or antiplatelet agent was common in 2 clinical trials of single-agent ibrutinib in patients with CLL and the pattern of use of these agents was characterized and bleeding adverse events (AEs) observed in 2 trials were described.
TL;DR: The efficacy observed in studies of the Bruton tyrosine kinase inhibitor, ibrutinib, confirms that BCR signaling is critical for the growth of B-cell malignancies.
Abstract: B-cell receptor (BCR) signaling plays a vital role in B-cell malignancies; Bruton tyrosine kinase is a critical mediator of this signaling. BCR signaling, either constitutively or following antigen binding, leads to activation of several downstream pathways involved in cell survival, proliferation and migration. The efficacy observed in studies of the Bruton tyrosine kinase inhibitor, ibrutinib, confirms that BCR signaling is critical for the growth of B-cell malignancies. Ibrutinib characteristically induces redistribution of malignant B cells from tissues into the peripheral blood and rapid resolution of adenopathy. Furthermore, ibrutinib therapy results in normalization of lymphocyte counts and improvement in cytopenias. Ibrutinib has been shown to have an excellent safety profile and does not cause myelosuppression. Early data from combination studies of ibrutinib with anti-CD20 monoclonal antibodies have shown more rapid responses compared to those seen with ibrutinib monotherapy. Current data strongly support continued clinical evaluation of ibrutinib in B-cell malignancies.
TL;DR: This study explored the combination of Len and rituximab in relapsed CLL with results suggesting TN pts could derive greater benefit than relapsed pts from Len + R given their less compromised immune function and a trend toward inferior ORR for patients with complex metaphase cytogenetics.
TL;DR: The group identified sorafenib (S) as potent inhibitor of FLT3-ITD mutant AML and demonstrated increased preclinical activity of S, which is associated with poor prognosis.
Abstract: 7033 Background: FLT3-ITD mutant AML is associated with poor prognosis. Our group identified sorafenib (S) as potent inhibitor of FLT3-ITD AML. We demonstrated increased preclinical activity of S w...