A Novel Bruton′s Tyrosine Kinase Inhibitor CC-292 In Combination With The Proteasome Inhibitor Carfilzomib Iimpacts Multiple Myeloma Bone Microenviroment With Resultant Anti-Myeloma Activity

Abstract A member of the Tec family kinases, Bruton’s tyrosine kinase (Btk) modulates B-cell development and activation, and plays an important role in antibody production. Interestingly, Btk and Tec (the other Tec kinase family) regulate osteoclast (OC) differentiation via Receptor Activator of Nuclear Factor κ B (RANK) signaling. Moreover, OCs derived from X-linked agammaglobulinemia (XLA) patients who harbor Btk null mutations have impaired function. Here we show that a potent and specific Btk inhibitor, CC-292 inhibits OC function in multiple myeloma (MM) patients. CC-292 is a highly selective, covalent Btk inhibitor. OC derived from MM patient monocytes were assayed with or without CC-292. Interestingly, OC function was significantly inhibited in the presence of CC-292 (100 nM and 1000 nM) as demonstrated by pit formation assay. However, mRNA expression for TRAP and Cathepsin K, two OC differentiation markers were increased in the presence of CC-292 suggesting that CC-292 inhibits OC function without inhibiting OC differentiation. OC sealing zone contributes to OC bone resorption function. Given the role of c-Src and Proline-rich tyrosine Kinase 2 (Pyk2) signaling in sealing zone formation and OC function we next evaluated CC-292’s effect on Pyk2 and c-Src. Pyk2 plays a role in OC activation and localizes to the sealing zone in OC. RANK signaling activates c-Src, which phosphorylates Pyk2. Moreover c-Src controls OC bone resorption by regulating actin organization via cortactin. Interestingly, CC-292 (100 nM) inhibited c-Src total protein, c-Src phosphorylation and Pyk2 phosphorylation. Furthermore, CC-292 (100 nM) inhibited cortactin protein and mRNA expression, and upregulated c-Cbl protein (E3 ubiquitin ligase for c-Src) expression in OC derived from MM patient monocytes with resultant inhibition of OC sealing zone formation. However, at the same low doses (100 nM) CC-292 did not show any direct in vitro effect against MM cell viability. Because carfilzomib, a proteasome inhibitor that binds irreversibly to its target, has potent anti-MM activity and also inhibits OC resorptive activity, we studied CC-292 in combination with carfilzomib. Our data suggests that carfilzomib (1.25 nM) has no impact on OC sealing zone formation but inhibits OC differentiation. CC-292 (100 nM) in combination with carfilzomib (1.25 nM) inhibited not only sealing zone formation but also OC differentiation, resulting in stronger suppression of OC function than carfilzomib alone. The combination of CC-292 (30mg/kg p.o. for 5 days per week for 6 weeks) and carfilzomib (3 mg/kg i.v. x 2 days per week for 4 weeks and 2 mg/kg i.v. x 2 days per week for 2 weeks) significantly inhibited tumor burden and myeloma cell numbers in a diffuse NOD-SCID MM model. The calvarial cells derived from these mice treated with CC-292 alone, carfilzomib alone or the combination showed higher osteocalcin mRNA (osteoblast differentiation marker) expression. A specific bone resorption marker, carboxy-terminal telopeptide collagen crosslinks (CTX) in mouse serum was significantly inhibited in CC-292 and CC-292 in combination with carfilzomib treatment groups in comparison with control mice. Furthermore, 3D microCT reconstructions showed increase in cancellous bone volume in lumbar vertebrae in mice treated with CC-292 or carfilzomib, while the combination treatment resulted in an increase in cancellous bone volume in an additive manner. These data demonstrate that the novel BTK inhibitor CC-292 inhibits OC function through inhibition of OC sealing zone formation. Moreover, CC-292 in combination with carfilzomib augments effects against the bone microenvironment with resultant anti-MM activity. Disclosures: Arastu-Kapur: Onyx Pharmaceuticals, Inc.: Employment. Evans:Celgene Avilomics Research: Employment, Equity Ownership. Singh:Celgene Avilomics Research: Employment, Equity Ownership. Kirk:Onyx Pharmaceuticals, Inc.: Employment. Westlin:Celgene Avilomics Research: Employment, Equity Ownership. Raje:Celgene: Consultancy; Millenium: Consultancy; Onyx: Consultancy; Amgen: Consultancy; Acetylon: Research Funding; Eli Lilly: Research Funding.

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AVL-292, a Bruton's Tyrosine Kinase Inhibitor Impacts Bone Resorption by Abrogating Osteoclast Sealing Zone Formation in Multiple Myeloma

Blood ◽

10.1182/blood.v120.21.1822.1822 ◽

2012 ◽

Vol 120 (21) ◽

pp. 1822-1822

Author(s):

Homare Eda ◽

Loredana Santo ◽

Diana Cirstea ◽

Andrew J. Yee ◽

Anuj Mahindra ◽

...

Keyword(s):

Bone Resorption ◽

Tyrosine Kinase ◽

Mrna Expression ◽

Mechanism Of Action ◽

Research Funding ◽

Bruton's Tyrosine Kinase ◽

Zone Formation ◽

Sealing Zone ◽

Btk Inhibitor ◽

Rank Signaling

Abstract Abstract 1822 The activation of Bruton's tyrosine kinase (Btk), a member of the Tec family of tyrosine kinases regulates B-cell development and activation, and plays a key role in antibody production. Interestingly, Btk and the other Tec kinase family, Tec, regulate OC differentiation via Receptor Activator of Nuclear Factor κ B (RANK) signaling. Moreover, patients with X-linked agammaglobulinemia (XLA) who harbor Btk null mutations have impaired OC function. Here we show that, a potent and specific inhibitor of Btk, AVL-292, inhibits OC function in MM patients. AVL-292 is a highly selective, covalent Btk inhibitor that potently silences Btk enzymatic activity (IC50 < 0.5nM) with high selectivity towards Btk with lack of significant inhibition against other kinases involved in BCR signaling (Syk, Lyn). We examined the mechanism of action of AVL-292 in the context of OCs function. OC derived from MM patient monocytes were assayed with or without AVL-292. Interestingly, OC function was inhibited in the presence AVL-292 as demonstrated by pit formation assay. However, mRNA expression of Cathepsin K and TRAP, markers of OC differentiation, were increased in the presence of AVL-292. These data suggest AVL-292 inhibits OC function without affecting the OC differentiation. It has been shown that BTK and Tec regulation of OC differentiation is related to calcium (Ca2+) signaling by increasing Ca2+ flux through direct phosphorylation of phospholipase C2 (PLCγ2). To delineate the mechanism of action of the BTK inhibitor against OC function, the RANK signaling proteins were detected by western blotting and Ca2+ concentration was measured by flourescence. AVL-292 inhibited phosphorylation of the BTK substrate, PLCγ2 in OCs. This was associated with an inhibition of intracellular Ca2+ release by AVL-292 which otherwise increased with RANKL stimulation in OCs. Given the effect of AVL-292 on RANK signaling we next evaluated its effect on Proline-rich tyrosine Kinase 2 (Pyk2) and c-Src. Pyk2 plays a role in OC activation and localizes to the sealing zone in OC. RANK signaling activates c-Src, which phosphorylates Pyk2. Moreover c-Src controls OC bone resorption by regulating actin organization via cortactin. Interestingly, AVL-292 inhibited c-Src and Pyk2 phosphorylation. Furthermore, AVL-292 inhibited cortactin protein and mRNA expression, and upregulated c-Cbl protein (E3 ubiquitin ligase for c-Src) expression in OCs derived from MM patient monocytes. These data demonstrate that the novel BTK inhibitor AVL-292 inhibits OC function through inhibition of OC sealing zone formation. These results suggest a potential novel mechanism of Btk inhibition with AVL-292 on osteoclast function and therefore bone resorption. Disclosures: Evans: Celgene: Employment. Singh:Celgene: Employment. Westlin:Celgene: Employment. Raje:Onyx: Consultancy; Celgene: Consultancy; Millenium: Consultancy; Acetylon: Research Funding; Amgen: Research Funding; Eli-Lilly: Research Funding.

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Specific Antagonists of NMDA Receptors Prevent Osteoclast Sealing Zone Formation Required for Bone Resorption

Biochemical and Biophysical Research Communications ◽

10.1006/bbrc.2000.2097 ◽

2000 ◽

Vol 268 (1) ◽

pp. 201-209 ◽

Cited By ~ 43

Author(s):

Cécile Itzstein ◽

Léon Espinosa ◽

Pierre D. Delmas ◽

Chantal Chenu

Keyword(s):

Bone Resorption ◽

Nmda Receptors ◽

Zone Formation ◽

Sealing Zone

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Phase 1 Clinical Trial of the Novel Structure Proteasome Inhibitor NPI-0052.

Blood ◽

10.1182/blood.v114.22.2693.2693 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2693-2693 ◽

Cited By ~ 2

Author(s):

Andrew Spencer ◽

Michael Millward ◽

Paul Mainwaring ◽

Simon Harrison ◽

Laurence Catley ◽

...

Keyword(s):

Solid Tumor ◽

Whole Blood ◽

Proteasome Inhibitor ◽

Mononuclear Cells ◽

Proteasome Inhibitors ◽

Proteasome Inhibition ◽

Pharmacokinetic Data ◽

Employment Equity ◽

Cognitive Changes ◽

Equity Ownership

Abstract Abstract 2693 Poster Board II-669 Background: NPI-0052 is a proteasome inhibitor with a novel bicyclic structure (other proteasome inhibitors in clinical use are peptide based). Preclinical studies indicate rapid, broad and prolonged inhibition of all 3 catalytic sites of the proteasome, and subsequently unique proteasome inhibition, signal transduction, toxicology and efficacy profiles. Taken together these suggest the potential for improvements in therapeutic ratio and activity in hematologic and solid tumor malignancies. Materials and Methods: Patients with solid tumor, lymphoma, leukemia or myeloma diagnoses without standard treatment options have been treated with IV NPI-0052 on one of two arms (weekly or twice weekly) in this 3+3 design dose escalation study. This is followed by 10 patient Recommended Phase 2 dose Cohorts of patients with lymphomas, CLL and myeloma respectively. Proteasome inhibition (pharmacodynamics) and pharmacokinetics are also assayed in whole blood, and proteasome inhibition in peripheral blood mononuclear cells (PBMC). Results: 44 patients have been treated with NPI-0052 at doses ranging from 0.075 mg/m2 to 0.9 mg/m2. Common adverse events include fatigue, parosmia/dysgeusia, transient peri-infusion site pain, lymphopenia, headaches, dizziness / unsteady gait, closed-eye visuals, cognitive changes. Incidence and grade of these events correlate with dose, being quite tolerable at the MTD of 0.7 mg/m2 on the weekly dosing arm. An MTD has not yet been determined for the twice weekly dosing arm. Pharmacokinetic data has demonstrated a rapid elimination half-life (<20 minutes) and relatively large volume of distribution. Assessment of proteasome inhibition has demonstrated increasing inhibition of chymotrypsin-like activity of up to 88% Day 1 and 100% Day 15. Inhibition of caspase-like and trypsin-like activity of up to 52% and 71% respectively has also been seen. Inhibition remains between doses in whole blood (principally RBC), but recovers between doses in PBMC. Clinical benefit, including stable disease, regression or response, was reported in patients with mantle cell lymphoma, myeloma, Hodgkin's lymphoma, cutaneous marginal zone lymphoma, follicular lymphoma, sarcoma, prostate carcinoma and melanoma. Conclusions: NPI-0052 produces dose-dependent pharmacologic effects through the predicted efficacious range, while producing a toxicity profile that is dissimilar to what is reported with other proteasome inhibitors (notably deficient in peripheral neuropathy, neutropenia and thrombocytopenia) in spite of producing equal or greater proteasome inhibition. These data indicate a broad range of potential uses, and led to additional studies in hematologic malignancies and solid tumors alone and in combination. Disclosures: Longenecker: Nereus Pharmaceuticals: Employment. Palladino:Nereus Pharmaceuticals: Employment, Equity Ownership. Lloyd:Nereus Pharmaceuticals: Employment, Equity Ownership. Neuteboom:Nereus Pharmaceuticals: Employment, Equity Ownership. Spear:Nereus Pharmaceuticals: Employment, Equity Ownership.

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Dual SYK/JAK Inhibition Overcomes Ibrutinib Resistance in Chronic Lymphocytic Leukemia

Blood ◽

10.1182/blood.v128.22.5377.5377 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5377-5377

Author(s):

Yue Lynn Wang ◽

Pin Lu ◽

Greg P Coffey ◽

Anjali Pandey ◽

Ailin Guo

Keyword(s):

Cell Death ◽

Research Funding ◽

Single Agent ◽

Lymphocytic Leukemia ◽

Prognostic Indicators ◽

Employment Equity ◽

Btk Inhibitor ◽

Equity Ownership ◽

Ibrutinib Resistance ◽

Novel Therapeutic Strategies

Abstract Ibrutinib (a BTK inhibitor) has generated remarkable responses in CLL. However, the drug, to a large extent, does not cause cell death directly and does not eradicate CLL malignant clones. Inability to eradicate CLL has fostered resistance generation. Once patients become resistant, they do poorly with a median survival of 3-4 months. Novel therapeutic strategies are needed to prevent resistance, improve treatment outcome and ultimately cure the disease. Herein, we explore dual targeting of the BCR and JAK-STAT pathways with a novel single agent, cerdulatinib, which selectively inhibits both SYK (a BCR component) and JAK kinases. We demonstrated that cerdulatinib delivered potent tumor inhibition in 60 primary CLL patient samples, especially in those with poor prognostic indicators. Importantly, cerdulatinib, but not ibrutinib, is able to overcome the support of microenvironment and induces CLL cell death at clinically achievable concentrations. Further, cerdulatinib blocked proliferation of ibrutinib-sensitive and ibrutinib-resistant primary CLL cells and of BTKC481S-transfected cells. These anti-tumor effects are correlated with the inhibition of BCR and JAK-STAT signaling and downstream inhibition of the functions of AKT, ERK and NFκB. Collectively, our results show that simultaneous targeting of BCR and JAK-STAT pathways is a more effective strategy relative to single BTK inhibition. Disclosures Coffey: Portola Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties, Research Funding. Pandey:Portola Pharmaceuticals: Employment, Equity Ownership, Patents & Royalties, Research Funding.

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Acalabrutinib in Patients with Relapsed/Refractory (R/R) and High-Risk, Treatment-Naive (TN) Chronic Lymphocytic Leukemia (CLL)

Blood ◽

10.1182/blood-2018-99-110395 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4424-4424 ◽

Cited By ~ 3

Author(s):

Clare C. Sun ◽

Pia Nierman ◽

Inhye E. Ahn ◽

Janet Valdez ◽

Jennifer Lotter ◽

...

Keyword(s):

Lymph Node ◽

High Risk ◽

Peripheral Blood ◽

Progressive Disease ◽

Lung Infection ◽

Lymphocytic Leukemia ◽

Employment Equity ◽

Time Points ◽

Btk Inhibitor ◽

Equity Ownership

Abstract Background: Bruton tyrosine kinase (BTK) is a critical component of B-cell receptor signaling and a validated target for CLL. Acalabrutinib is a highly selective, potent, covalent BTK inhibitor, which has shown promising efficacy and safety in patients with CLL, including high-risk patients. We present preliminary efficacy, safety, and pharmacodynamic results from an ongoing single-center, open-label, phase 2 study of acalabrutinib monotherapy in patients with R/R and high-risk, TN CLL. Methods: Patients with R/R or high-risk (chromosome 17p deletion [del17p] or mutation in TP53 or NOTCH1) TN CLL/small lymphocytic lymphoma (SLL) who met International Workshop on Chronic Lymphocytic Leukemia (IWCLL) 2008 criteria for treatment and had an Eastern Cooperative Oncology Group performance status ≤2 were eligible. Patients who had prior BTK inhibitor therapy were excluded. Patients were randomized to receive oral acalabrutinib 100 mg twice daily (BID) or 200 mg daily (QD) until progressive disease or unacceptable toxicity. The primary endpoint was investigator-assessed overall response rate (ORR) by IWCLL 2008 criteria with modification for lymphocytosis. Secondary endpoints included safety and BTK occupancy. BTK occupancy was measured with a biotin-tagged analogue probe in peripheral blood cells at drug trough time points after 3 days of dosing and after 1, 6, and 12 mo of treatment. BTK occupancy in lymph node samples was measured at drug trough time points after 3 days of dosing. Results: Forty-six patients were enrolled and treated (100 mg BID, n=22; 200 mg QD, n=24). The median age was 64 years (range, 45-83), and 35% (16/46) were TN. Approximately 39% of patients (25% of TN) had bulky lymph nodes ≥5 cm, 37% (50% of TN) had Rai stage III-IV disease at baseline, 76% (88% of TN) had unmutatedIGHV, 21% (40% of TN) had del(17p), 21% (23% of TN) had TP53 mutation, and 47% (54% of TN) had NOTCH1 mutation. As of April 13, 2018, the median time on study for all treated patients was 20 mo (range 1-39), with 89% (41/46) remaining on acalabrutinib. Two patients (9%) in the BID group and 3 patients (13%) in the QD group discontinued treatment due to an adverse event (AE; n=1), progressive disease (n=1), and other reasons (n=3). The patient who discontinued due to progressive disease (BID group) achieved partial response at 2 mo and developed Richter transformation at 6 mo. The ORR was 90% (95% CI: 76, 97) for efficacy evaluable patients (N=39), defined per protocol as patients who had ≥ 6 mo of acalabrutinib (Table). ORR was 95% (75, 100) and 84% (60, 97) for the BID and QD group, respectively. For the intent-to-treat population (N=46), ORR was 80% (66, 91). Most AEs were grade 1/2 and did not require dose delays or modifications. The most common AEs (all grades; >25%) were headache (63%), contusion (50%), diarrhea (43%), upper respiratory tract infection (43%), arthralgia (33%), influenza-like illness (28%), maculo-papular rash (28%), myalgia (26%), and nausea (26%). Grade 3/4 AEs occurred in 33% (15/46) of patients (BID, 27% [6/22]; QD, 38% [9/24]), most commonly (>10%) infections (13%; urinary tract infection, lung infection, hepatitis B reactivation, which led to treatment discontinuation and fatal hepatic failure after 10 mo of treatment, and an invasive pulmonary aspergillosis at 2 mo in the setting of prolonged neutropenia and recent systemic corticosteroid use that led to treatment discontinuation) and neutropenia (11%). Approximately 33% (15/46) of patients (BID, 23% [5/22]; QD, 42% [10/24]) reported serious AEs (all grades), most commonly (>5%) lung infection (7%). No atrial fibrillation was reported, and one grade 1 atrial flutter occurred (BID). On day 4 of cycle 1, median trough BTK occupancy was significantly higher for the BID group versus the QD group in the peripheral blood (95% vs 87%; P<0.001) and in the lymph node (98% vs 90%, P<0.001). Median trough BTK occupancy in the peripheral blood was also higher for the BID group at 1, 6, and 12 mo (range, 98%-99% for BID vs 95%-97% for QD; P<0.05 at all time points). Conclusion: Acalabrutinib monotherapy produced high ORR in R/R and high-risk TN CLL, with an acceptable safety profile. The study was not designed to detect a statistically significant difference in clinical outcomes between the dosing groups. Near complete target coverage (>95%) was more rapidly achieved with 100 mg BID than 200 mg QD dosing in the lymph node and peripheral blood. Disclosures Nierman: National Institutes of Health: Employment. Covey:Acerta Pharma: Employment; AstraZeneca: Equity Ownership. Hamdy:Acerta Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: various patents for ACP-196. Izumi:Acerta Pharma: Employment, Equity Ownership, Patents & Royalties: Acerta Pharma, various patents for ACP-196. Liu:Acerta Pharma: Employment. Patel:Acerta Pharma: Employment, Equity Ownership. Wiestner:Pharmacyclics LLC, an AbbVie Company: Research Funding.

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Partial Reconstitution of Humoral and Cellular Immunity in Patients with Chronic Lymphocytic Leukemia Treated with Acalabrutinib

Blood ◽

10.1182/blood-2018-99-111919 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1874-1874 ◽

Cited By ~ 3

Author(s):

Christopher Pleyer ◽

Clare C. Sun ◽

Pia Niermann ◽

Xin Tian ◽

Inhye E. Ahn ◽

...

Keyword(s):

Bone Marrow ◽

T Cell ◽

Lymphocytic Leukemia ◽

Light Chains ◽

Free Light Chains ◽

Employment Equity ◽

Cell Numbers ◽

Serum Iga ◽

Btk Inhibitor ◽

Equity Ownership

Abstract Introduction Immune dysregulation in chronic lymphocytic leukemia (CLL) contributes to a high rate of infections and morbidity. We previously reported that treatment of CLL with ibrutinib, a Bruton tyrosine kinase (BTK) inhibitor, leads to partial reconstitution of humoral immunity and fewer infections, especially in patients who achieved a ≥50% increase in serum IgA levels. Acalabrutinib is also an irreversible BTK inhibitor that is more selective than ibrutinib and has demonstrated safety and efficacy in the treatment of relapsed or refractory CLL. It is currently unclear how the increased specificity of acalabrutinib affects immune reconstitution and infection rates. We assessed the immunological impact of acalabrutinib in patients with CLL treated with single-agent acalabrutinib. Methods Samples originated from a phase 2, single-center trial studying acalabrutinib 100 mg twice daily (BID) or acalabrutinib 200 mg once daily (QD) in patients with relapsed/refractory (RR) CLL or high-risk, treatment naïve (TN) CLL (chromosome 17p deletion or mutation in TP53 or NOTCH1) (NCT02337829). Patients who received at least 6 months of acalabrutinib and had paired longitudinal data available were included in the analyses. Patients receiving IV immunoglobulin replacement were excluded from analysis of IgG levels. Additionally, patients with detectable monoclonal IgG, IgA and/or IgM proteins on serum immunofixation were excluded from analysis of the corresponding immunoglobulin isotype. The analysis of free light chains was stratified based on k or λ restriction of CLL cells determined by flow cytometry. Immunohistochemical staining of bone marrow biopsies was performed: T cell numbers were estimated by CD3 staining and the degree of CD68-positive macrophage extensions in contact with CLL cells were semi-quantitatively assessed on a scale from 0 (no extensions) to 4 (maximum number of extensions). The Wilcoxon signed-rank test and the Mann-Whitney U test were used to compare paired and unpaired data, respectively. Differences in the rate of infection between groups were examined using the Cox regression model for recurrent events. Results Serum IgA levels increased as early as 3 months after the initiation of acalabrutinib (median increase 35.7%, P = .0001), with levels sustained up to 24 months (Figure 1), whereas serum IgG and IgM levels were not affected by acalabrutinib. There was no difference (P > .05) in IgA, IgG, IgM trend between TN or RR CLL. Furthermore, there was no difference (P > .05) in IgA, IgG and IgM trends between patients treated with QD compared to BID dosing of acalabrutinib. Among 20 k-restricted and 18 λ-restricted CLL cases, the involved (tumor-derived) free light chain was elevated at baseline and trended toward the normal range after 3 months of acalabrutinib therapy consistent with an anti-tumor effect (k: median decrease 55.4%; P < .0001 and λ: median decrease 49.1%; P = .0003). The uninvolved free light chain did not change (P > .05). Peripheral blood CD3+, CD4+ and CD8+ T cell counts were elevated above the laboratory reference range at baseline and normalized after 6 months (CD4+ median decrease 49.2%; P = .0074 and CD8+ median decrease 54.8%; P = .003). T cell numbers in the bone marrow did not appreciably change. However, treatment-induced changes of the immune microenvironment were apparent in tumor-macrophage interactions. At baseline, macrophages tightly interacted with CLL cells, often with multiple podocytes making contact with CLL cells. On acalabrutinib, we observed a decrease in these macrophage podocyte interactions (P = .0007). At a median follow-up of 20 months, 31 (68.9%) patients developed a total of 68 infections, including 7 (10.3%) grade 3 and 1 (1.5%) grade 4 infections. Patients with superior immune reconstitution, as defined by an increase in serum IgA of ≥ a median of 36% from baseline to 3 months, had a significantly lower rate of infections (risk ratio = 0.52, P = 0.029). Conclusions These data indicate that acalabrutinib allows for partial reconstitution of humoral and cell-mediated immunity and disrupts macrophage-CLL cell interaction in the bone marrow microenvironment in patients with CLL. Furthermore, acalabrutinib did not interfere with uninvolved free light chains, suggesting that acalabrutinib selectively inhibits CLL B-cells and does not impair normal B-cell function. Disclosures Izumi: Acerta Pharma: Employment, Equity Ownership, Patents & Royalties: Acerta Pharma, various patents for ACP-196. Hamdy:Acerta Pharma: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Acerta Pharma, various patents for ACP-196. Wiestner:Pharmacyclics LLC, an AbbVie Company: Research Funding.

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Health Care Utilization and Costs Among Patients with Chronic Myeloid Leukemia Using Tyrosine Kinase Inhibitors

Blood ◽

10.1182/blood-2018-99-113809 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3537-3537

Author(s):

Joanna C Huang ◽

Sudeep Karve ◽

Sanchita Porwal ◽

Kushan Thakkar ◽

Thomas Marshall ◽

...

Keyword(s):

Tyrosine Kinase ◽

Emergency Room ◽

Tyrosine Kinase Inhibitors ◽

Health Plan ◽

Real World ◽

Index Date ◽

Kinase Inhibitors ◽

Employment Equity ◽

The Us ◽

Equity Ownership

Abstract INTRODUCTION: Tyrosine kinase inhibitors (TKIs) remain mainstay in the management of patients with CML. Several TKIs have been approved over the last two decades. Even though efficacy and safety remain as the primary drivers in treatment selection, in recent years importance has been placed on treatment affordability and economic burden associated with the long-term cancer treatments such as TKIs. However, current literature lacks real-world data on healthcare utilization (HCU) and costs among patients with CML using TKIs, which this study aims to address. METHODS: Retrospective cohort study was conducted using MarketScan Commercial, and Supplemental Medicare databases (2012-2016). Data includes medical and pharmacy utilization and costs for over 90 million individuals enrolled in employer-sponsored health-plans in the US. Data includes information on but not limited to medical diagnosis, procedures, drugs dispensed, date of service, health plan enrollment. Study involves adult patients (≥18 years) with ≥2 medical claims with a diagnosis of CML (ICD-9-CM: 205.10 - 205.12; ICD-10: C92.10-C92.12) and with a prescription claim for TKI. The date of first-TKI claim defined the index date. Patients were required to have continuous health plan enrollment ≥6 months before (defined as baseline period) and ≥6 months after index date. Selected patients were further classified into 5 sub-groups based on the index TKI observed (prescribed) post CML diagnosis (imatinib, dasatinib, nilotinib, bosutinib, ponatinib). Among the selected patients, all-cause HCU and costs were assessed from index date until end of database or end of enrollment, whichever occurred earlier. HCU and associated costs were assessed overall and by care settings including inpatient, emergency room, physician office, outpatient hospital, outpatient pharmacy, nursing facility and ancillary care. In addition, baseline (6 month) utilization and costs were assessed. Monthly and annual resource utilization and costs were reported for the overall CML cohort (across all TKI users) and by index TKI sub-groups. All costs were reported from a payer perspective (i.e., costs reimbursed by health plan) and adjusted to 2017 US dollars using the US consumer price index (medical component). All analyses were descriptive in nature. RESULTS: The study cohort included 2,213 CML patients. Distribution for the index TKI treatment was as follows: 41% imatinib, 36% dasatinib, 21% and 1% each for bosutinib and ponatinib. Mean age (standard deviation [SD]) of the cohort was 55 (15) years which was similar for individual TKI sub-groups. Majority of patients were males (55%) and 56% were enrolled in a preferred provider organization plan. The mean follow-up duration post-TKI initiation was 607 (442) days. The average baseline monthly all-cause costs were $4,365 with inpatient and pharmacy costs accounting for over 3/4th of the total costs (Figure 1). Post-TKI initiation the average monthly costs were twice ($9,288) compared with the baseline costs ($4,365) and the increase was primarily attributable to higher outpatient pharmacy costs ($6,619, accounted for 71% of total costs) (Figure 2). Monthly costs across other care settings (inpatient, outpatient, emergency room) were similar for the baseline and post-TKI initiation. On average patients had 1.4 office visits, 2.5 prescriptions and 0.7 hospital outpatient visits per month at baseline, which increased by 23%, 38% and 49%, respectively post TKI-initiation. During the 1st year post TKI-initiation, 17% patients in the overall CML cohort had at least 1 inpatient admission and this was consistent across individual TKI-sub-groups (except ponatinib, 50%). CONCLUSIONS: Findings on TKI utilization and costs in employer-sponsored health-plan database indicate that average costs and utilization were similar across the TKI sub-groups with pharmacy costs accounting for 71% of the total post TKI initiation costs. Overall, this study helps address the literature gap by providing recent real-world treatment care-setting specific utilization and costs among TKI uses and these data can be of value to several healthcare stakeholders including physicians, managed care plans and researchers in supporting clinical and formulary decisions and also serve as inputs for economic models. Finally, the sample sizes for ponatinib and bosutinb were small and results for these TKIs should be interpreted with caution. Disclosures Huang: ZS Associates: Employment; Novo Nordisk Inc: Equity Ownership; AstraZeneca: Research Funding. Karve:AbbVie: Employment, Equity Ownership. Porwal:ZS Associates: Employment. Thakkar:ZS Associates: Employment. Marshall:AbbVie: Employment, Equity Ownership. Rosenberg:AbbVie: Employment, Equity Ownership.

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Loxo-305, a Highly Selective and Non-Covalent Next Generation BTK Inhibitor, Inhibits Diverse BTK C481 Substitution Mutations

Blood ◽

10.1182/blood-2019-126114 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 4644-4644 ◽

Cited By ~ 4

Author(s):

Eliana B. Gomez ◽

Lippincott Isabel ◽

Mary S. Rosendahal ◽

Stephen M. Rothenberg ◽

Steven W. Andrews ◽

...

Keyword(s):

Acquired Resistance ◽

Binding Affinities ◽

Next Generation ◽

Wild Type ◽

Employment Equity ◽

Equilibrium Binding ◽

Btk Inhibitor ◽

Equity Ownership ◽

Substitution Mutations ◽

Btk Inhibitors

Introduction: Bruton's Tyrosine Kinase (BTK) is an essential component of normal and malignant B-cell receptor signaling. Covalent BTK inhibitors have transformed the treatment of B-cell malignancies but are limited by off-target toxicity and acquired resistance, leading to eventual treatment discontinuation and disease progression. Emerging evidence suggests that acquired resistance is mediated predominantly by BTK C481 substitution mutations at the covalent BTK inhibitors' binding site. There is significant unmet clinical need for new treatment approaches that overcome acquired resistance and minimize toxicity. LOXO-305 is a highly selective, non-covalent, next generation BTK inhibitor. We previously showed that LOXO-305 potently inhibited both wild-type (WT) BTK and BTK C481S -mediated kinase activity in enzyme and cell-based assays with nanomolar potency, caused regression of BTK-dependent lymphoma mouse xenograft models, and was more than 300-fold selective for BTK over 98% of 370 other kinases tested and showed no significant inhibition of non-kinase off targets at 1 mM (Brandhuber et al. SOHO 2018). In addition, ADME and pharmacokinetic experiments in two preclinical species predicted that LOXO-305 will have high human exposure and sustained BTK C481S target coverage in patients at clinically achievable doses. Here we describe the activity of LOXO-305 against additional BTK C481 substitution mutations, including mutations identified in patients with acquired resistance to covalent BTK inhibitors. We further determine equilibrium-binding affinities for LOXO-305 for diverse mutant BTK enzymes in comparison to other clinically available BTK inhibitors. Methods: To assess cellular BTK inhibitor potency, HEK293T cell lines transiently expressing wild-type BTK and BTK C481 substitution mutations were serum starved and incubated with LOXO-305 overnight. Cells were next incubated with serum and orthovanadate for 5 min and the phosphorylated Y223 BTK was analyzed by immunoblot. Bands were quantified and the IC50 values calculated with GraphPad Prism. The equilibrium-binding affinities for targeted BTK inhibitors to BTK enzyme variants were determined by surface plasmon resonance (SPR) using the Biacore T200. Biotinylated BTK variants were immobilized on a docked streptavidin coated sensor chip. Five concentrations of each inhibitor plus blank controls were analyzed. Association/dissociation rate constants were calculated by global fitting of the data to a 1:1 binding interaction model. Results: While BTK C481S possessed similar levels of basal Y223 autophosphorylation as wild-type BTK in cells, BTK C481T autophosphorylation was reduced by ~50%, C481R by ~90%, and mutants C481F, and C481Y were inactive in HEK293T cells. LOXO-305 inhibited Y223 phosphorylation of all active mutants with similar nanomolar potency. In contrast, autophosphorylation of all BTK C481 mutants were resistant to both Ibrutinib and acalabrutinib. Equilibrium-binding affinities of LOXO-305 for select BTK C481 substitution mutations confirmed LOXO-305's superior potency versus commercially available BTK inhibitors (ibrutinib and acalabrutinib). Conclusions: The next generation, non-covalent, highly selective BTK inhibitor LOXO-305 potently inhibited the cellular activity of BTK C481S, T and R mutations and displayed strong equilibrium binding to WT BTK and several BTK C481 substitution mutations. Together with high selectivity and significant BTK target coverage in vivo, these results indicate that LOXO-305 may overcome acquired resistance to covalent BTK inhibitors in patients without significant off-target toxicity. A phase 1 clinical trial of LOXO-305 is currently underway. Disclosures Gomez: LOXO Oncology Inc.: Employment, Equity Ownership. Isabel:Loxo Oncology: Employment. Rosendahal:Loxo Oncology: Employment. Rothenberg:LOXO Oncology Inc.: Employment. Andrews:Loxo Oncology: Employment. Brandhuber:LOXO Oncology Inc.: Employment, Equity Ownership.

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Targeting Bruton's Tyrosine Kinase As a Novel Approach to Inhibit Osteoclast Function in Multiple Myeloma

Blood ◽

10.1182/blood.v118.21.2882.2882 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2882-2882

Author(s):

Homare Eda ◽

Loredana Santo ◽

Diana D. Cirstea ◽

Samantha Pozzi ◽

Miriam Canavese ◽

...

Keyword(s):

Multiple Myeloma ◽

B Cell ◽

Board Of Directors ◽

Cell Activation ◽

B Cell Activation ◽

Advisory Committees ◽

Pit Formation ◽

Btk Inhibitor ◽

Equity Ownership ◽

Rank Signaling

Abstract Abstract 2882 Bone disease is a hallmark of multiple myeloma (MM) and targeting osteoclasts (OC) to alleviate bone destruction is a component of the standard of care for MM. The activation of Bruton's tyrosine kinase (Btk), a member of the Tec family of tyrosine kinases, regulates B-cell activation and development and plays an important role in antibody production. Interestingly, Btk activation also occurs downstream of RANK signaling in OCs and its activation stimulates essential calcium signaling which plays an important role in OC function. Given this dual role of BTK in both B cell activation and osteoclastogenesis, we studied its role in the context of multiple myeloma (MM). Accordingly, we examined the efficacy of a potent and specific inhibitor of Btk (AVL-292) in OCs derived from MM patient monocytes. AVL-292 is a highly selective, covalent Btk inhibitor that potently silences Btk enzymatic activity (IC50 < 0.5nM) and inhibits primary B cell proliferation and activation (EC50 ∼ 10nM). The compound showed high selectivity towards Btk when tested in a broad kinase panel of 62 kinases and importantly did not show significant inhibition against other kinases involved in BCR signaling (Syk, Lyn). OC derived from MM patient monocytes were assayed with or without AVL-292 for OC maturation by TRAP staining and functional activity by resorptive pit formation assay. OC function was inhibited in the presence of AVL-292 as determined by a decrease in pit formation. To delineate the mechanism of action of AVL-292 against OC function, the RANK signaling proteins were detected by western blotting and intracellular Ca2+ concentration was measured by fluorescence. AVL-292 inhibited phosphorylation of the Btk substrate, PLC γ2 in OCs. This was associated with an inhibition of intracellular Ca2+ release by AVL-292 which otherwise increased with RANKL stimulation in OCs. Although AVL-292 did not demonstrate direct cytotoxicity or inhibition of proliferation of MM cells, ongoing studies are confirming its activity in the context of co-cultures with accessory cells like OCs. These data demonstrate that the novel BTK inhibitor AVL-292 inhibits OC function through inhibition of Ca2+ mobilization through RANK signaling. These results suggest inhibition of Btk with AVL-292 has therapeutic potential for the treatment of myeloma related bone disease. Disclosures: Evans: Avila Therapeutics: Employment, Equity Ownership. Singh:Avila Therapeutics: Employment, Equity Ownership. Raje:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Millenium: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Acetylon: Research Funding.

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The Bruton's Tyrosine Kinase (BTK) Inhibitor PCI-32765 Induces Durable Responses in Relapsed or Refractory (R/R) Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL): Follow-up of a Phase Ib/II Study

Blood ◽

10.1182/blood.v118.21.983.983 ◽

2011 ◽

Vol 118 (21) ◽

pp. 983-983 ◽

Cited By ~ 9

Author(s):

Susan O'Brien ◽

Jan A. Burger ◽

Kristie A. Blum ◽

Richard R. Furman ◽

Steven E. Coutre ◽

...

Keyword(s):

B Cell ◽

Research Funding ◽

Objective Response ◽

Cellular Migration ◽

Phase Iii ◽

Employment Equity ◽

Phase Ib ◽

Btk Inhibitor ◽

Equity Ownership

Abstract Abstract 983 Introduction: Btk is a central mediator of B-cell receptor signaling which is essential for normal B-cell development. PCI-32765 is an orally-administered irreversible inhibitor of Btk which induces apoptosis and inhibits cellular migration and adhesion in malignant B-cells. An early analysis of the phase Ib/II study PCYC-1102 showed PCI-32765 to be highly active and tolerable in patients with CLL (Byrd, ASCO 2011). Here we report longer-term follow-up of this multicenter phase Ib/II trial. Methods and Patients: Two cohorts of CLL patients (previously untreated ≥65 years old and relapsed/refractory [R/R] disease following at least 2 prior therapies, including fludarabine) were treated with oral PCI-32765 administered daily for 28-day cycles until progression of disease. Doses of 420mg (previously untreated and R/R) and 840mg daily (R/R) were examined. The patients with R/R disease are the subject of this report. Results: Sixty-one R/R CLL/SLL patients were enrolled (420mg cohort n=27, 840mg cohort n=34). The median follow-up time for the 420mg cohort is 10.2 months and for the 840mg cohort is 6.5 months. The median number of prior treatment regimens for the 420mg cohort was 3 (2–10) and for the 840mg cohort was 5 (1–12). Seventy-two percent of patients had at least one poor-risk molecular feature: del(17p) 31%, del(11q) 33%, IgVH un-mutated 57%. Treatment has been well tolerated. Two patients have discontinued for adverse events (AE); 6 patients have required reduction of PCI-32765 dose (420mg cohort 2/27, 840mg cohort 4/34). Grade 1 or 2 diarrhea, fatigue, nausea, and ecchymosis have been the most frequently reported AEs. Serious AEs (SAEs) have occurred in 38% of patients; SAEs considered potentially related to PCI-32765 have occurred in 10% of patients. Grade ≥3 AEs considered potentially related to PCI-32765 occurred in 21% of patients. A characteristic pattern of response, with a transient phase of lymphocytosis typically peaking within the first 2 months of Rx, followed by resolution over time, has been observed in the majority of patients. Objective response (ORR; PR + CR) by IWCLL criteria in the 420mg cohort cohort, previously reported as 48% with 6.2 months median follow-up (Byrd, et al ASCO 2011), is now 70% with 10.2 months median follow-up. ORR in the 840mg cohort is 44% at 6.5 months median follow-up. An additional 19%, and 35% of patients in these cohorts, respectively, have a nodal PR (>50% reduction in aggregate lymph node size) with residual lymphocytosis. ORR appears to be independent of molecular risk features. Eighty-two percent of patients (50/61; 420mg cohort 22/27, 840mg cohort 28/34) remain on PCI-32765. Only 8% (5/61) of patients have had progressive disease (PD); 6-month PFS is 92% in the 420mg cohort and 90% in the 840mg cohort. Treatment cessation not related to PD or AE includes: death (n=2) or investigator discretion (n=3). Conclusions: The potent Btk inhibitor PCI-32765 is well tolerated and is associated with high rates of 6-month PFS in R/R CLL/SLL. Phase III trials of PCI-32765 in CLL/SLL are planned. Disclosures: O'Brien: Pharmacyclics, Inc: Research Funding. Burger:Pharmacyclics, Inc: Research Funding. Blum:Pharmacyclics: Research Funding. Furman:Pharmacyclics, Inc: Research Funding. Coutre:Pharmacyclics, Inc: Research Funding. Sharman:Pharmacyclics, Inc: Research Funding. Flinn:Pharmacyclics, Inc: Research Funding. Grant:Pharmacyclics, Inc: Research Funding. Heerema:Pharmacyclics, Inc: Research Funding. Johnson:Pharmacyclics, Inc: Research Funding. Navarro:Pharmacyclics, Inc: Employment, Equity Ownership. Holmgren:Pharmacyclics, Inc: Consultancy. Hedrick:Pharmacyclics: Employment, Equity Ownership. Byrd:Pharmacyclics, Inc: Research Funding.

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