Spleen Tyrosine Kinase (Syk) Inhibitors Block B Cell Receptor Signaling and Survival In Chronic Lymphocytic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3604-3604
Author(s):  
Julia Hoellenriegel ◽  
Greg Coffey ◽  
Uma Sinha ◽  
Anjali Pandey ◽  
William G. Wierda ◽  
...  
Keyword(s):  
Cell Viability ◽  
B Cell ◽  
Cell Activation ◽  
Kinase Inhibitor ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Clinical Activity ◽  
B Cell Malignancies ◽  
Bcr Signaling ◽  
Syk Inhibitor

Abstract Abstract 3604 B cell antigen receptor (BCR) signaling is increasingly recognized as a key factor promoting clonal expansion in various B cell malignancies, such as diffuse large B cell lymphoma and CLL. Engagement of the BCR receptor activates Syk, which leads to a number of downstream events that promote cell survival and growth. Therefore, inhibition of Syk represents a novel therapeutic approach in CLL. Another Syk inhibitor (fostamatinib disodium/R788) has clinical activity in patients with CLL (Blood 115: 2570, 2010). R788 is a relatively selective Syk inhibitor, but also displays activity against Flt3, Jak, and Lck. In this study we tested two highly selective Syk inhibitors (P142-76 and P505-15) and a multi-kinase inhibitor (P420-89) for their efficacy to antagonize BCR-related CLL cell activation and survival responses. We found that BCR crosslinking with anti-IgM significantly increased CLL cell viability compared to controls, and this pro-survival effect of BCR triggering was abrogated by treatment with the Syk inhibitors P142-76 and P505-15. Figure A shows contour plots that depict CLL cell viability in a representative case, treated with anti-IgM in the presence or absence of the Syk inhibitors. The mean relative CLL cell viability at 48 hours was decreased to 78% ± 4% (P142-76), 62% ± 5% (P505-15) or 50% ± 4.5% (P420-89) of controls (means ± SEM, n=19). Additionally, we found that the inhibitors induce apoptosis in CLL cells in co-culture with nurselike cells (NLC), indicating that Syk inhibition antagonizes microenvironment-derived survival signals which may or may not be related to the BCR. For example, P505-15 significantly reduced CLL cell viability in NLC co-cultures from 84.4% ± 5% to 46% ± 8% at 48 hours (mean ± SEM, n=6,*P< 0.05, summarized in Fig. B). The chemokines CXCL12 and CXCL13 regulate migration and homing of CLL cells within the CLL microenvironment, and CLL cell responsiveness to these chemokines is modulated by BCR signaling. Therefore, we evaluated the effects of the Syk inhibitors on CLL cell chemotaxis towards these chemokines. P505-15 decreased chemotaxis toward CXCL12 and CXCL13 to levels that were 49.5% ± 5% or 32.8% ± 6% of respective controls. In response to BCR crosslinking, CLL cells secrete the chemokines CCL3 and CCL4, which foster interactions between CLL cells and the leukemia microenvironment. This was almost completely abrogated by inhibiting Syk. For example, preincubation with P505-15 significantly reduced CCL3 supernatant levels from 8400 pg/mL ± 1166 pg/mL to 2263 pg/mL ± 744 pg/mL (mean ± SEM, n=5, *P< 0.05). This inhibition of CCL3/4 secretion by CLL cells could also be demonstrated in CLL co-cultures with NLC. Finally, we found that P505-15 blocked BCR-induced activation of the p44/42 MAP kinase, using anti-phospho-MAPK (ERK1/2) antibodies. In summary, our findings demonstrate that specific Syk inhibitors are highly effective in disrupting BCR-derived survival and cell migration-related responses in CLL cells. These data support the clinical development of these new, promising agents in patients with CLL and other selected B cell malignancies. Disclosures: Coffey: Portola Pharmaceuticals: Employment. Sinha:Portola Pharmaceuticals: Employment. Pandey:Portola Pharmaceuticals: Employment.

Phosphoinositide 3’-Kinase (PI3K) Delta Inhibition with CAL-101 Blocks B-Cell Receptor (BCR) Signaling and the Prosurvival Actions of Nurslike Cells (NLC), In Chronic Lymphocytic Leukemia

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 48-48
Author(s):  
Julia Hoellenriegel ◽  
Sarah A Meadows ◽  
William G. Wierda ◽  
Michael J Keating ◽  
Brian Lannutti ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Cell Viability ◽  
B Cell ◽  
Cell Activation ◽  
Lymphocytic Leukemia ◽  
Cytotoxic Agents ◽  
Cross Linking ◽  
Clinical Activity ◽  
Bcr Signaling

Abstract Abstract 48 BCR signaling is increasingly recognized as a central mechanism for disease progression in CLL. PI3K transmits various external, microenvironment-derived signals that influence survival, drug resistance, and cell migration of CLL cells. PI3K isoforms have distinct functions and tissue distributions. P110δ mutant mice display defective BCR signaling, along with impaired B cell development and differentiation. Because of this unique role of p110δ in BCR signaling, p110δ inhibitors have been developed for treatment of B cell malignancies and autoimmune disorders. CAL-101, a potent and selective p110δ showing an IC50 of 2.5 nM in vitro and >200-fold selectivity relative to other PI3K isoforms, displays pre-clinical and clinical activity in CLL. Prior in vitro CLL studies revealed that CAL-101 induces caspase-dependent apoptosis, and inhibits CD40L-, BAFF-, TNF-alpha- and fibronectin-derived survival signals. Because of the importance of p110δ in BCR signaling, we tested the effects of CAL-101 on BCR-derived CLL cell activation, and confirmed our findings in correlative studies related to an ongoing CAL-101 phase I clinical trial. We found that BCR cross-linking with anti-IgM significantly increased CLL cell viability to 121 ± 5 % of controls (mean ± SEM, n=15, *P< 0.05).This pro-survival effect was abrogated by CAL-101, which reduced CLL cell viability to 85± 3 % of controls at 48 hours (mean ± SEM, n=15, *P< 0.05). CLL cell viability in co-culture with NLC was also significantly reduced by CAL-101 to 64± 6% of untreated controls at 48 hours (mean ± SEM, n=10, *P< 0.05). BCR cross-linking induces secretion of the chemokines CCL3 and CCL4 by CLL cells, which was quantified in CLL supernatants by ELISA. CAL-101 significantly reduced supernatant CCL3 concentrations from 4060 ± 1392 pg/mL to 2901 ± 1220 pg/mL, and CCL4 levels from 5721 ± 1789 pg/mL to 3223 ± 1311 pg/mL (mean ± SEM, n=6, *P<0.05). In CLL-NLC co-cultures, CAL-101 also inhibited CCL3/4 secretion by CLL cells.Here, the CCL3 concentrations were reduced by CAL-101 from 943 ± 535 pg/mL to 156 ± 8 pg/mL, and the CCL4 concentrations from 7433 ± 4463 pg/mL to 316 ± 53 pg/mL (mean ± SEM, n=5, *P<0.05).CAL-101 also decreased CXCL13 levels in CLL-NLC co-cultures from 151 ± 35 to 70 ± 27 pg/mL (mean ± SEM, n=4, *P=0.05), indicating that CAL-101 has pharmacological actions on both, CLL cells and the CLL microenvironment as represented by the NLC. Given the importance of cytotoxic agents in the therapy of patients with CLL, we evaluated whether a combination of CAL-101 with bendamustine, could overcome stroma-mediated drug resistance in CLL cells co-cultures with marrow stromal cells (MSC). Fig A shows contour plots of a representative case that depict CLL cell viability after treatment with CAL-101, bendamustine, or the two drugs combined. Fig. B displays a bar diagram that depicts the mean relative viabilities of CLL cells treated with CAL-101 (5 mM),bendamustine(10 mM),or the drug combination (mean ± SEM, n=4). The consistently higher CLL cell death of CLL cells treated with the combination of both drugs indicates an additive effect. Next, we used phospho-flow to demonstrate that CAL-101 inhibits constitutive and BCR-induced PI3K pathway activation in samples obtained from CLL patients undergoing treatment with CAL-101. CAL-101 treatment down regulated pAkt(T308) in peripheral CLL cells by >90% (n=12). Plasma samples from 14 CLL patients obtained before and after 28 days of daily treatment with CAL-101 were analyzed for concentrations of various cytokines. Interestingly, these analyses revealed substantial decreases from baseline to Day28+ of CAL-101 treatment in mean plasma levels of CCL3 (from 186 pg/mL to 29 pg/mL), CCL4 (from 303 to 70 pg/mL),CCL22 (1067 to 533 pg/mL), CXCL13 (316 pg/mL to 40 pg/mL), and TNFα(104 to 29 pg/mL), confirming our in vitro data related to CCL3/4 and CXCL13. Collectively, our data demonstrate that CAL-101 effectively inhibits BCR- and NLC-mediated CLL cell survival and activation in vitro. Also, CAL-101 enhances the activity of cytotoxic agents such as bendamustine against CLL cells. Our in vivo data indicate that CAL-101 decreases elevated pre-treatment CCL3 and CCL4 levels. These findings are consistent with the concept that inhibition of BCR-derived signals could be a key mechanism of action of CAL-101 in CLL. The results also support clinical evaluation of CAL-101 in combination with bendamustine for the treatment of CLL. Disclosures: Meadows: Calistoga Pharmaceuticals: Employment. Lannutti:Calistoga Pharmaceutical Inc.: Employment.

The Bruton's Tyrosine Kinase Inhibitor, PCI-32765, Is Well Tolerated and Demonstrates Promising Clinical Activity In Chronic Lymphocytic Leukemia (CLL) and Small Lymphocytic Lymphoma (SLL): An Update on Ongoing Phase 1 Studies

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 57-57 ◽  
Author(s):  
Jan A. Burger ◽  
Susan O'Brien ◽  
Nathan Fowler ◽  
Ranjana Advani ◽  
Jeff Porte Sharman ◽  
...  
Keyword(s):  
B Cell ◽  
Phase 1 ◽  
Study Drug ◽  
Lymphocytic Leukemia ◽  
Clinical Activity ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Bcr Signaling ◽  
Equity Ownership ◽  
Grade 3

Abstract Abstract 57 Introduction: Bruton's tyrosine kinase (Btk) is a downstream mediator of B-cell receptor (BCR) signaling and is not expressed in T-cells or NK-cells. As such, Btk represents an ideal therapeutic target for B-cell malignancies dependent upon BCR signaling. Chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL) has been reported to have constitutively active BCR signaling. PCI-32765 is a potent, selective, irreversible and orally bioavailable small molecule inhibitor of Btk that has pre-clinical activity in B-cell malignancies (Proc Natl Acad Sci 2010;107(29):13075-80). PCI-32765 was therefore moved forward to a Phase 1 study in B-cell malignancies including patients (pts) with CLL/SLL. A subsequent CLL/SLL-specific Phase 1b study was initiated to further explore safety, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy of PCI-32765. This report includes a composite summary of the CLL/SLL experience in both of these studies. Pts and Methods: Pts with CLL/SLL who had relapsed or refractory disease after >1 prior treatment regimens were eligible for treatment in each of the studies whereas the second Phase 1b study also included a cohort of elderly pts (aged ≥ 65 years) with CLL/SLL who required treatment and were “treatment-naive”. Responses were assessed by the investigator using the International Working Group CLL criteria (Hallek et al, Blood 2008 for pts with CLL) and the International Workshop to Standardize Response Criteria for Non-Hodgkin's Lymphomas (Cheson et al, J Clin Oncol 2007 for pts with SLL). Results: To date, 30 CLL/SLL patients (including 4 treatment-naive) have been enrolled across the 2 studies. Eighty-four percent of subjects are men with an overall median age of 68 (range 44–82) years. Of the subjects with prior therapy for CLL/SLL the median number of prior therapies is 3 (range 1–4). Treatment has been well-tolerated; Grade ≥ 3 toxicities have been infrequent (10/30 pts; 33%). Two study-drug related serious adverse events have been reported: 1 case of viral adenitis (Grade 3) and 1 case of viral infection (Grade 2). Two adverse events have led to discontinuation of study drug: a small bowel obstruction (Grade 3) and exacerbation of chronic obstructive disease (Grade 3); both events were reported as unrelated to study drug. No study-drug related deaths have reported. There has been no change in either NK cell or T cell counts. Target inhibition as measured by a probe of Btk drug occupancy showed inhibition of Btk at PCI-32765 exposure levels of ≥ 245 ng•h/mL. Of the 14 patients currently evaluable for response using the pre-defined criteria, the overall response rate is 64% (1 complete remission [CR], 8 partial remissions [PR], and 4 SD). Both studies are ongoing and open to enrollment. An update on response rate, response duration, safety, and PD information will be presented on enrolled patients based on a November 2010 database cut-off. Conclusion: PCI-32765 is a novel oral and selective “first-in-human” inhibitor of Btk that induces objective partial and complete responses in a substantial proportion of pts with CLL/SLL and has a favorable safety profile. These data support further studies of both monotherapy and also combination treatment with PCI-32765 in CLL/SLL. Disclosures: O'Brien: Pharmacyclics, Inc: Honoraria, PI grant. Fowler:Pharmacyclics: Consultancy, Research Funding. Advani:Pharmacyclics, Inc: Honoraria, PI grant. Sharman:Pharmacyclics, Inc: Honoraria, PI grant. Furman:Pharmacyclics, Inc: PI grant. Izumi:Pharmacyclics, Inc: Employment. Buggy:Pharmacyclics, Inc: Employment, Equity Ownership. Loury:Pharmacyclics: Employment, Equity Ownership. Hamdy:Pharmacyclics, Inc: Employment, Equity Ownership.

scholarly journals Recurrent Mutations within the Nfkbie gene: A Novel Mechanism for NF-κB Deregulation in Aggressive Chronic Lymphocytic Leukemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 297-297
Author(s):  
Larry Mansouri ◽  
Lesley-Ann Sutton ◽  
Viktor Ljungstrom ◽  
Sina Bondza ◽  
Linda Arngarden ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Mutant Allele ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
B Cell Lymphomas ◽  
Tlr Signaling ◽  
B Cell Malignancies ◽  
Recurrent Mutations ◽  
Genomic Aberrations

Abstract Dysregulated NF-κB signaling appears to be particularly important in B-cell malignancies, with recurrent mutations identified within both the canonical and non-canonical NF-κB pathways, as well as in components of the B-cell receptor (BcR) and Toll-like receptor (TLR) signaling pathways. In chronic lymphocytic leukemia (CLL), although recurrent mutations have been identified in MYD88 (TLR signaling) and BIRC3 (non-canonical NF-κB pathway), their frequency is low (<3%) and hence the extent to which genetic aberrations may contribute to constitutional NF-κB activation remains largely unknown. To gain further insight into this issue, we designed a HaloPlex gene panel (Agilent Technologies) and performed targeted next-generation sequencing (NGS) (HiSeq 2000/Illumina) of 18 NF-κB genes in a discovery cohort of 124 CLL patients, intentionally biased towards poor-prognostic patients with either unmutated IGHV genes or high-risk genomic aberrations. Using a conservative cutoff of >10% for the mutant allele, we identified mutations (n=35) within 30/124 (24%) patients in 14/18 NF-κB genes analyzed. IκB genes, which encode for cytoplasmic inhibitor proteins, accounted for 20/35 (57%) mutations, with IκBε (encoded by NFKBIE) mutated in 8 patients; notably, 3/8 cases carried an identical 4bp deletion within exon 1 of NFKBIE. Prompted by these findings, we proceeded to validate our findings in an independent CLL cohort (n=168) using the same methodology as above and primarily focusing on cases with poor-prognostic features. We identified 30 mutations within 28 CLL patients in 11/18 NF-κB genes analyzed. Strikingly, 13/30 mutations were found within IκBε, with 10/13 patients carrying the same 4bp NFKBIE deletion. Notably, investigations into whether additional cases (within both the discovery and validation cohort) may harbor mutations of low clonal abundance (<10% mutant allele), led to the detection of the NFKBIE deletion in another 18 cases. Owing to the prevalence of this 4bp deletion within the NFKBIE gene, we developed a GeneScan assay and screened an additional 312 CLL cases. Collectively, 40/604 (6.6%) CLL patients were found to carry this frame-shift deletion within the NFKBIE gene, which is in line with a recent publication reporting that 10% of Binet stage B/C patients carried this mutation (Damm et al. Cancer Discovery 2014). Remarkably, the majority of these NFKBIE mutations (16/40) were found in a subgroup of patients that expressed highly similar or stereotyped BcRs and are known to have a particularly poor outcome, denoted as subset #1. This finding thus alludes to a subset-biased acquisition and/or selection of genomic aberrations, similar to what has been reported for subset #2 and SF3B1, perhaps as a result of particular modes of BcR/antigen interaction. We utilized proximity-ligation assays to test the functional impact of the NFKBIE deletion by investigating protein-protein interactions. This analysis revealed reduced interaction between the inhibitor IκBε and the transcription factor p65 in NFKBIE-deleted CLL cells; IκBε-knock-down shRNA experiments confirmed dysregulated apoptosis/NF-κB signaling. Finally, to assess whether the NFKBIE deletion could also be present in other B-cell malignancies, we screened 372 mature B-cell lymphoma cases using NGS or the GeneScan assay and found the deletion in 7/136 (5.1%) mantle cell lymphomas, 3/66 (4.5%) diffuse large B-cell lymphomas and 3/170 (1.8%) splenic marginal zone lymphomas. Taken together, our analysis revealed that inactivating mutations within the NFKBIE gene lead to NF-κB activation in CLL and potentially several other B-cell-derived malignancies. Considering the central role of BcR stimulation in the natural history of CLL, the functional loss of IκBε may significantly contribute to sustained CLL cell survival and shape the disease evolution. This novel data strongly indicates that components of the NF-κB signaling pathway may be prime targets for future targeted therapies not only in CLL but also other mature B-cell lymphomas. Disclosures No relevant conflicts of interest to declare.

A Phase II Trial of Ofatumumab In Subjects with Waldenstrom's Macroglobulinemia.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1795-1795 ◽  
Author(s):  
Richard R. Furman ◽  
Herbert Eradat ◽  
Julie C. Switzky ◽  
Suzanne R. Hayman ◽  
Craig C. Hofmeister ◽  
...  
Keyword(s):  
B Cell ◽  
Research Funding ◽  
Plasma Cells ◽  
Cell Lymphoma ◽  
International Workshop ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Clinical Activity ◽  
Rapid Rise ◽  
Grade 3

Abstract Abstract 1795 Background: Waldenstrom's macroglobulinemia (WM) is an indolent B-cell lymphoma characterized by a heterogeneous population of lymphocytes, plasmacytoid lymphocytes and plasma cells with variable CD20 expression. Rituximab (R) achieves an overall response rate (ORR) of 25–50% in relapsed/refractory WM and is associated with IgM flares, manifested by a rapid rise in IgM, potentially leading to complications of hyperviscosity. Ofatumumab (OFA) is a fully human monoclonal antibody that targets an epitope encompassing both the large and small extracellular loops of CD20 and effectively induces complement-dependent cytotoxicity of B-lymphoma cells. OFA is approved for the treatment of fludarabine- and alemtuzumab-refractory chronic lymphocytic leukemia (CLL) and has demonstrated clinical activity in non-Hodgkin's lymphoma. Given the efficacy of OFA in CLL, with its decreased CD20 antigen density, similar to WM where CD20 is down-regulated with differentiation of cells into plasma cells, a Phase II, open-label, single-arm trial of OFA in patients (pts) with WM was initiated to examine the safety and efficacy of OFA in this population. We report data from a planned interim analysis, which was performed to examine IgM flare, toxicity and response data. Methods: Pts (age ≥18 years) with WM requiring therapy by 2nd International Workshop on WM criteria were eligible. Pts received OFA 300 mg week 1 and 1000 mg weeks 2–4. Premedication included acetaminophen and antihistamine (all infusions) and glucocorticoid (infusions 1 and 2). Pts who experienced grade 3–4 infusion-related adverse events (AEs) during weeks 1 and 2 also received glucocorticoid during weeks 3 and 4. The primary endpoint was ORR assessed by 3rd International Workshop on WM criteria, and toxicity was assessed according to NCI-CTCAE, v3.0. Results: Fifteen pts were enrolled between March 2009 and January 2010. Median age was 59 years (range 43–85), and 9 pts were male. Pts had a median IgM level of 3.70 g/dL (range 1.21–6.62) and median hemoglobin (hgb) of 9.8 g/dL (range 5.3–11.7). Three pts were previously untreated; 12 pts had received a median of 3 therapies (range 2–5), including 11 pts who had received R, and 7 pts who had received a purine analog. Fourteen pts completed all 4 infusions of OFA. One pt withdrew from study after infusion 3 due to a drug-related serious AE (SAE). One pt had cryoglobulinemia, which interfered with IgM assessment. Of the 14 pts with evaluable IgM levels, 3 achieved partial response (PR), and 3 achieved minor response (ORR=43%) 8 weeks to 5 months after start of OFA therapy. One of 3 previously untreated pts and 5 of 12 relapsed pts responded. Four of 11 pts who had received prior R and 2 of 4 R-naïve pts responded. Five of 9 pts with IgM <4 g/dL and 1 of 5 pts with IgM >4 g/dL responded. Four pts with a median hgb of 8.0 g/dL (range 5.3–9.2) experienced ≥2.8 g/dL increase in hgb, including 3 pts who had >5 g/dL increase; median time to reach hgb ≥11.0 was 4 weeks. Infusion-related events occurred with dose 1 (300 mg) in 12 pts and with dose 2 (1000 mg) in 7 pts; all infusion events were grade 1–2 except 2 grade 3 events (rash, serum sickness). Nine pts developed 11 infections: 7 URI, 2 UTI, 1 sinusitis, 1 oral candidiasis (all grade 2). One pt developed grade 3 febrile neutropenia. Two pts developed SAEs possibly related to OFA. One pt developed grade 3 Coombs-negative hemolytic anemia after infusion 3 resulting in study withdrawal, and 1 pt with a baseline IgM level of 6.62 g/dL developed grade 3 renal insufficiency due to a rapid rise in IgM and cast nephropathy 6 weeks after starting OFA. One additional pt, with a baseline IgM level of 4.69 g/dL, developed a rapid rise in IgM and hyperviscosity symptoms. Both pts with a rapid rise in IgM underwent plasmapheresis with resolution of symptoms. No other OFA-related hematologic toxicity was observed. Conclusions: OFA has an acceptable toxicity profile, although a rapid rise in IgM requiring plasmapheresis was observed in 2 pts with high baseline IgM levels. OFA shows clinical activity in pts with WM, including those who relapse after R therapy, with rapid improvement in hgb and slower reduction of IgM levels. Based on the acceptable safety profile in this study and the dose of OFA approved for refractory CLL, the study was amended to increase the OFA dose to 2000 mg and allow a 2nd cycle of therapy for pts who do not attain PR after cycle 1. Accrual to the amended study is ongoing. Disclosures: Furman: GlaxoSmithKline: Consultancy, Speakers Bureau; Genentech: Consultancy, Speakers Bureau; Cephalon, Inc.: Speakers Bureau; Celegene: Consultancy; Calistoga: Consultancy. Off Label Use: Ofatumumab is an investigational anti-CD20 monoclonal antibody, currently under development for the treatment of B-cell malignancies (chronic lymphocytic leukemia, diffuse large B-cell lymphoma, Waldenstroms macroglobulinemia and follicular lymphoma) as well as autoimmune diseases (rheumatoid arthritis and multiple sclerosis). Switzky:GlaxoSmithKline: Employment, Research Funding; Genmab: Employment, Research Funding. Leonard:GlaxoSmithKline: Consultancy. Liao:GSK: Employment. Shah:GlaxoSmithKline: Employment; Genmab: Research Funding. Brownell-Buttich:GlaxoSmithKline: Employment. Lisby:Genmab A/S: Employment. Lin:GlaxoSmithKline: Consultancy, Employment.

TGR-1202, a Novel Once Daily PI3Kδ Inhibitor, Demonstrates Clinical Activity with a Favorable Safety Profile, Lacking Hepatotoxicity, in Patients with Chronic Lymphocytic Leukemia and B-Cell Lymphoma

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1984-1984 ◽  
Author(s):  
Howard A. Burris ◽  
Manish R. Patel ◽  
Danielle M. Brander ◽  
Owen A. O'Connor ◽  
Changchun Deng ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Hematologic Malignancies ◽  
Tumor Burden ◽  
Lymphocytic Leukemia ◽  
Clinical Activity ◽  
Employment Equity ◽  
Previous Formulation ◽  
Equity Ownership

Abstract Background: TGR-1202 is a novel oral, next generation PI3Kδ inhibitor which notably lacks the hepatotoxicity associated with other PI3Kδ inhibitors. Preliminary data from an ongoing Ph I study of TGR-1202 demonstrated clinical activity in patients with advanced hematologic malignancies (ASCO 2014). Herein we present updated results from this Phase I, first in human study of TGR-1202 in patients with relapsed and/or refractory CLL and B-cell lymphoma. Methods: TGR-1202 is administered orally once daily following a 3+3 dose escalation design. Previously treated patients with an ECOG PS ≤ 2 and confirmed diagnosis of B-cell non-Hodgkin lymphoma (NHL), chronic lymphocytic leukemia (CLL), or other lymphoproliferative disorders are eligible. Endpoints include safety, PK/PD, and efficacy. Results: 49 patients have been enrolled to date of various lymphoma subtypes including CLL, follicular lymphoma (FL), Hodgkin’s lymphoma (HL), DLBCL, mantle cell lymphoma (MCL), and marginal zone lymphoma (MZL). Demographics: 76% male, ECOG 0/1/2: 17/31/1, median age of 59 yrs (range: 22-85), median prior treatment regimens: 3 (range: 1-14), and 43% were refractory to prior treatment. 35 patients have been treated at doses ≥ 800 mg of a previous formulation where a threshold effect in activity was observed, and 6 have been treated with an improved micronized formulation (≥ 200 mg). TGR-1202 was well tolerated and no MTD has been reached to date. The only Gr≥3 AE occurring in >5% of patients was neutropenia (8%). AE’s of all grades occurring in >20% of patients were limited to diarrhea (24%), cough (22%), fatigue (20%), and nausea (20%). Notably, in comparison to other PI3Kδ inhibitors, no hepatotoxicity and no cases of colitis have been observed to date. Rates of infection and pneumonia have also been low (12% and 6%, respectively), and no cases of febrile neutropenia have been reported. Of the 41 patients treated at ≥ 800 mg of the previous formulation or with the micronized formulation, 32 are evaluable for efficacy (6 too early to evaluate, 2 non-compliant, 1 did not meet I/E criteria). Responses have been limited in patients with aggressive lymphoma and HL. Of the 9 evaluable CLL patients, 8 (89%) achieved a nodal PR (median nodal reduction of 71%), of which 5 achieved a PR per Hallek 2008 criteria with the remaining 4 having persistent lymphocytosis. The 1 CLL patient with SD had a >40% nodal reduction and remains on study. Of the 7 evaluable FL patients, all have shown clinical benefit with a reduction in tumor burden with 2 having achieved a PR, and the remaining 5 patients in SD. Additionally 2 MZL patients each achieved SD with >25% nodal reductions and remain on study. Notably, no patient with CLL or indolent lymphoma (FL & MZL) treated at ≥800 mg has progressed to date (median time on study of 20 weeks, range 6 – 73+), and no patient who achieved >50% reduction in tumor burden (including patients with CLL, FL, and HL) has progressed, with median time on study of 34 weeks (range 7 – 68+). Pharmacodynamic analysis in CLL patients indicates rapid suppression of pAKT at doses of 400 mg QD of the previous formulation. Conclusions: TGR-1202 is well tolerated in patients with relapsed and/or refractory hematologic malignancies with no reported hepatotoxicity or events of colitis and promising clinical activity. Enrollment continues in expansion cohorts and with the micronized formulation. Disclosures Brander: Celgene: Mentor received research funding Other. O'Connor:Celgene: Consultancy; Millennium Pharmaceuticals: Consultancy. Miskin:TG Therapeutics, Inc.: Employment, Equity Ownership. Sportelli:TG Therapeutics: Employment, Equity Ownership. Vakkalanka:Rhizen: Employment, Equity Ownership. Flinn:Infinity Pharmaceuticals: Consultancy.

SYK Is Involved in the CD38 Signal Transduction Pathway in Chronic Lymphocytic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2910-2910
Author(s):  
Marco Benkisser-Petersen ◽  
Maike Buchner ◽  
Arlette Dörffel ◽  
Marcus Dühren von Minden ◽  
Kerstin Leberecht ◽  
...  
Keyword(s):  
B Cell ◽  
Signal Transduction Pathway ◽  
Lymphocytic Leukemia ◽  
Transduction Pathway ◽  
Cd38 Expression ◽  
Bcr Signaling ◽  
Syk Inhibitor ◽  
And Migration ◽  
Stimulation Of ◽  
Proliferation And Migration

Abstract B-cell chronic lymphocytic leukemia (CLL) is one of the most prevalent B cell malignancies in adults and characterized by expansion of monoclonal mature B cells. Survival and proliferation of CLL cells depends on microenvironmental contact in lymphoid organs. The transmembrane glycoprotein CD38 acts as an important mediator of survival, proliferation and migration signals for CLL cells, and its expression is associated with poor prognosis. Spleen tyrosine kinase (SYK) is a central element of the B-cell receptor signal transduction pathway and has additionally been shown to be involved in cytokine and integrine signaling. In this study we demonstrate direct involvement of SYK in the CD38 signaling pathway in primary CLL samples. CD38-stimulation of primary CLL cells by its ligand CD31 induced a consistent phosphorylation of the tyrosine residue Y352, the first activation site that releases SYK from its autoinhibitory conformation (p<0.001). SYK downstream targets AKT (p<0.05) and ERK (p<0.05) were subsequently induced and prolonged CD38-stimulation increased MCL-1-expression (p<0.05). Concomitant inhibition of SYK with the SYK inhibitor R406 resulted in inhibition of AKT- and ERK-activation (p<0.05 and p<0.01) and prevented upregulation of MCL-1 (p<0.01). Moreover, we observed SYK-dependent enhancement of BCR-signaling after CD38 ligation. Short-term exposure of CLL cells to CD31 led to an increase of ERK-phosphorylation after BCR-engagement by 41.9% (p<0.05). This effect was completely abolished by concomitant R406-treatment (p<0.05). Additionally, we observed a SYK-dependent increase of Ca2+-flux in response to BCR-stimulation after previous CD38 activation. Moreover, preliminary experiments show that prolonged CD38-stimulation led to a SYK-dependent increase of baseline Ca2+-flux in CLL cells, indicating a potential involvement of CD38 in autonomous BCR-signaling. CD38 acts as an enhancer of migratory stimuli in CLL cells. We therefore analysed, whether SYK is also involved in this interaction process. CXCL12-dependent migration was increased by CD38 stimulation with the agonistic CD38 antibody IB4 by 28.3% (p=0.12). Treatment of CLL cells with R406 completely inhibited IB4-mediated migration (p<0.01). The expression of CD38 is regulated by a variety of mechanisms, including CD40 ligation. SYK is involved in CD40 signaling. We therefore tested, whether SYK-inhibition affects CD38-expression. Stimulation of CLL cells with recombinant CD40L resulted in a significant increase of CD38-expression (p<0.05). This effect was reversed by concomitant SYK-inhibition (p<0.01). In addition, we observed marked down-regulation of CD38 surface-expression (p<0.05) and mRNA-expression (p<0.05) for CLL cells treated with SYK-inhibitors R406 or P505-15 compared to vehicle control. This effect is at least partly based on transcriptional inhibition of CD38-regulators NF-kB (p<0.05) and E2A (p<0.05). Finally, we observed a clear correlation between CD38 expression on CLL cells and SYK-inhibitor efficacy (p<0.01). In conclusion, our data show that SYK acts as a central downstream effector of CD38 signaling regulating survival-, proliferation-, and migration pathways in CLL and also functions as a strong regulator of CD38 expression. The interaction of CD38 and SYK involves the BCR pathways, where CD38 enhances the response to BCR-stimulation and, moreover, may act as an enhancer of autonomous BCR-signaling in CLL. Additionally, the CD38-SYK interaction involves BCR-independent microenvironmental pathways as shown for CD40 and CXCL12. CD38 expression not only serves as a negative prognostic marker but has also been shown to possess biological significance in CLL. We therefore propose that disruption of the CD38-SYK axis may represent a promising therapeutic option in CLL. Disclosures No relevant conflicts of interest to declare.

Phase I/II study of MEDI-551, a humanized monoclonal antibody targeting CD19, in subjects with relapsed or refractory advanced B-cell malignancies.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 8065-8065 ◽  
Author(s):  
Trishna Goswami ◽  
Andres Forero ◽  
Mehdi Hamadani ◽  
Anne Sonet ◽  
Gregor Verhoef ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Phase I ◽  
B Cell ◽  
Transmembrane Protein ◽  
Single Agent ◽  
Tumor Lysis Syndrome ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
B Cell Malignancies ◽  
Antibody Targeting

8065 Background: Novel B-cell targeting agents, including monoclonal antibodies such as rituximab, are among recent advances in treatment of B-cell malignancies. New approaches are needed for patients progressing after rituximab-based therapies. MEDI-551 is an afucosylated monoclonal antibody targeting CD-19, a B-cell restricted transmembrane protein with enhanced affinity and antibody-dependent cellular cytotoxicity. Methods: Pts with relapsed or refractory follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia, or multiple myeloma received single agent MEDI-551 at dosages ranging from 0.5 mg/kg to 12 mg/kg via intravenous infusion over 28-day cycles; cohorts 1-6 received 0.5, 1, 2, 4, 8, and 12 mg/kg, respectively. Results: 25 pts were enrolled in the phase I portion Jun 2010–Aug 2011. No maximum tolerated dose (MTD) was achieved. Most AEs were grade 1/2 with dose-independent frequency and severity (Table). Six pts had grade 3 toxicities including tumor lysis syndrome, infusion reaction, thrombocytopenia, and neutropenia, or grade 4 neutropenia. No grade 5 AEs were seen. All pts recovered. Three partial responses (PR) and 2 complete responses (CR) were seen in DLBCL and FL pts at 0.5, 4, and 8 mg/kg. Activity included a CR lasting 9 mo. in a FL pt in cohort 1, who is currently being retreated with MEDI-551 on relapse. Conclusions: MEDI-551 demonstrated a safety profile warranting further study and showed no MTD reached at the highest dose studied. Anti-tumor activity is suggested by the responses achieved across dose levels. Phase II is currently enrolling subjects. This study is funded by MedImmune, LLC. [Table: see text]

scholarly journals Cooperation between SYK and ZAP70 Kinases As a Driver of Oncogenic BCR-Signaling in B-Cell Malignancies

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3922-3922
Author(s):  
Teresa Sadras ◽  
Jevon Cutler ◽  
Julia Aguade-Gorgorio ◽  
Zhengshan Chen ◽  
Kadriye Nehir Cosgun ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
B Cell Lymphoma ◽  
Kinase Domain ◽  
Leukemic Cells ◽  
B Cell Malignancies ◽  
Linker Region ◽  
Sh2 Domains ◽  
Bcr Signaling ◽  
Survival Signals

Abstract The spleen tyrosine kinase (SYK) and ζ-associated protein of 70 kD (ZAP70) tyrosine kinases play critical roles in proximal signal transduction of B-cell (BCR) and T-cell receptors (TCR), respectively. The highly similar SYK and ZAP70 kinases share a common structure composed of two tandem SH2 domains and a carboxy-terminal kinase domain. A linker region, termed interdomain B, connects the SH2 domains to the kinase domain and is important for kinase activation. Despite their conserved structure, SYK and ZAP70 are expressed in a largely mutually exclusive manner and play analogous roles in BCR- and TCR-signaling. Cross-lineage activation of ZAP70 in B cells was previously identified in chronic lymphocytic leukemia (CLL), which is characterized by clonal accumulation of malignant CD5+ B-cell cells that retain dependency on the BCR for survival signals. Nearly half of CLL cases show co-expression of SYK and ZAP70, and these patients have an aggressive disease course and a poor prognosis. Our analysis shows that in addition to CLL, aberrant ZAP70 expression occurs in other B-cell malignancies, e.g. TCF3-PBX1 pre-B ALL and B-cell lymphoma subsets that depend on survival signals from a functional (pre-) BCR. These findings suggest that interactions between SYK and ZAP70 may function to fine-tune strength of oncogenic BCR-signaling. To test this hypothesis, we have used a combination of molecular and proteomic approaches. We studied mechanisms by which ZAP70 integrates into BCR-mediated signals, and how the function of ZAP70 in B-cells differs from its native role downstream of the TCR. We demonstrate that ectopically expressed SYK and ZAP70 proteins are constitutively phosphorylated in BCR-ABL1+ B-ALL cells, but these induce distinctive signaling thresholds. CRISPR-mediated deletion of SYK or ZAP70 in leukemic cells further revealed that SYK and ZAP70 regulate unique signaling pathways in B-cells. We also demonstrate that ZAP70 is activated following BCR stimulation of lymphoma cells, and SYK/ZAP70 co-expressing cells display enhanced BCR signaling. Interestingly, enhanced BCR signaling was also observed in cells engineered to express an alternative splice variant of SYK (SYK-S). This shorter isoform of SYK, lacks a 23 amino-acid insert in the interdomain-B linker region, which is also absent in ZAP70, and may define unique protein-interactions that modulate signaling outcome. To elucidate the differential interactome of SYK, SYK-S, and ZAP70 we performed proximity-dependent biotin identification (BioID) experiments in B-cells following BCR-activation to capture the core signalling networks of these kinases in leukemic cells. In addition to expected BCR components including BLNK, PTPN6 and CBL we identified novel SYK and ZAP70 associated molecules including IKZF3, LAT2 and WAS which may play important roles in the survival of BCR-dependent malignancies. Importantly our findings highlight a role for ZAP70 in oncogenic BCR-signaling and suggest that ZAP70 promotes oncogenic BCR-signaling by limiting the ability of the BCR to induce negative B-cell selection and cell death. Disclosures No relevant conflicts of interest to declare.

scholarly journals Immunomodulatory Drugs for the Treatment of B Cell Malignancies

2021 ◽  
Vol 22 (16) ◽  
pp. 8572
Author(s):  
Nikolaos Ioannou ◽  
Khushi Jain ◽  
Alan G. Ramsay
Keyword(s):  
Combination Therapy ◽  
B Cell ◽  
Cell Lymphoma ◽  
Single Agent ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
Immune Recognition ◽  
Immunomodulatory Drugs ◽  
B Cell Malignancies ◽  
Cellular Compartments

Accumulating evidence suggests that the tumor microenvironment (TME) is involved in disease progression and drug resistance in B cell malignancies, by supporting tumor growth and facilitating the ability of malignant cells to avoid immune recognition. Immunomodulatory drugs (IMiDs) such as lenalidomide have some direct anti-tumor activity, but critically also target various cellular compartments of the TME including T cells, NK cells, and stromal cells, which interfere with pro-tumor signaling while activating anti-tumor immune responses. Lenalidomide has delivered favorable clinical outcomes as a single-agent, and in combination therapy leads to durable responses in chronic lymphocytic leukemia (CLL) and several non-Hodgkin lymphomas (NHLs) including follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL), and mantle cell lymphoma (MCL). Recently, avadomide, a next generation cereblon E3 ligase modulator (CELMoD), has shown potent anti-tumor and TME immunomodulatory effects, as well as promising clinical efficacy in DLBCL. This review describes how the pleiotropic effects of IMiDs and CELMoDs could make them excellent candidates for combination therapy in the immuno-oncology era—a concept supported by preclinical data, as well as the recent approval of lenalidomide in combination with rituximab for the treatment of relapsed/refractory (R/R) FL.

scholarly journals VLA-4 Expression and Activation in B Cell Malignancies: Functional and Clinical Aspects

2020 ◽  
Vol 21 (6) ◽  
pp. 2206 ◽  
Author(s):  
Andrea Härzschel ◽  
Antonella Zucchetto ◽  
Valter Gattei ◽  
Tanja Nicole Hartmann
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Types ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Clinical Aspects ◽  
Neoplastic Disease ◽  
B Cell Differentiation ◽  
B Cell Malignancies ◽  
Bcr Signaling

Lineage commitment and differentiation of hematopoietic cells takes place in well-defined microenvironmental surroundings. Communication with other cell types is a vital prerequisite for the normal functions of the immune system, while disturbances in this communication support the development and progression of neoplastic disease. Integrins such as the integrin very late antigen-4 (VLA-4; CD49d/CD29) control the localization of healthy as well as malignant B cells within the tissue, and thus determine the patterns of organ infiltration. Malignant B cells retain some key characteristics of their normal counterparts, with B cell receptor (BCR) signaling and integrin-mediated adhesion being essential mediators of tumor cell homing, survival and proliferation. It is thus not surprising that targeting the BCR pathway using small molecule inhibitors has proved highly effective in the treatment of B cell malignancies. Attenuation of BCR-dependent lymphoma–microenvironment interactions was, in this regard, described as a main mechanism critically contributing to the efficacy of these agents. Here, we review the contribution of VLA-4 to normal B cell differentiation on the one hand, and to the pathophysiology of B cell malignancies on the other hand. We describe its impact as a prognostic marker, its interplay with BCR signaling and its predictive role for novel BCR-targeting therapies, in chronic lymphocytic leukemia and beyond.

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