Inhibition Of PI3K-δ and -γ Isoforms By IPI-145 In Chronic Lymphocytic Leukemia Overcomes Signals From PI3K/AKT/S6 Pathway and Promotes Apoptosis

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4167-4167 ◽  
Author(s):  
Kumudha Balakrishnan ◽  
Marisa Peluso ◽  
Min Fu ◽  
Nathalie Y. Rosin ◽  
Jan A. Burger ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Therapeutic Potential ◽  
Lymphocytic Leukemia ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Enhanced Production ◽  
Significant Difference ◽  
Equity Ownership

Abstract The functional relevance of the B cell Receptor (BCR) pathway and identification of protein kinases as therapeutic targets have recently shifted the paradigm for treatment of B cell malignancies. Inhibition of protein and lipid kinases (Bruton Tyrosine Kinase [BTK] and phosphoinositide 3-kinase [PI3K]) with ibrutinib and GS-1101 has been shown to be active in treatment of chronic lymphocytic leukemia (CLL). Importantly, differential expression and function of PI3K isoforms support isoform-selective inhibition of this kinase in CLL. Whilst PI3K-α and PI3K-β are ubiquitously expressed, PI3K-δ and PI3K-γ are primarily restricted to leukocytes. Since CLL cells generally express high levels of active PI3K-δ, great interest has been focused on inhibition of PI3K-δ. However, given the distinct and non-overlapping roles of PI3K-δ and PI3K-γ in immune cells, exploration of the therapeutic potential of combined inhibition of both PI3K-δ and PI3K-γ in CLL patients is warranted. IPI-145 is a potent, orally bioavailable, inhibitor of PI3K-δ and PI3K-γ isoforms with KD values of 0.023 nM and 0.24 nM, respectively. Treatment of primary CLL cells (n=51) with IPI-145 (1 µM) resulted in significant apoptosis (median 33%; range 12 – 40%). Patients with mutated (n=13) or unmutated IGHV gene status (n=13), previously untreated (n=21) or treated (n=8), displayed no significant difference in apoptosis from IPI-145. Samples with different prognostic markers such as 13q (del) or FISH negative samples were equally sensitive to IPI-145. Side by side studies of IPI-145 with ibrutinib and GS-1101, revealed that IPI-145 is comparatively potent (IC50 7.6 µM, compared to >10 µM) in promoting apoptosis. Crosslinking with anti-IgM enhanced the survival of primary CLL cells in association with activation of PI3K-δ,γ/AKTSer473/pBadSer136/S6Ser235/236 pathway, which was in turn mitigated upon treatment with IPI-145 (n=9). Consistent with cell death, cleavage of PARP and decrease in anti-apoptotic protein Mcl-1 (but not Bcl-2 or Bcl-xL) was observed. Measurement of the C-C chemokine, CCL3, a biomarker for BCR signaling inhibition in CLL, demonstrated 15 to 48 – fold increase upon anti-IgM stimulation, which was reversed when cells were treated with 1 µM IPI-145 (10 to 80-fold decrease; n=6). Alternatively, co-culturing CLL primary cells with bone marrow stromal cells to mimic the leukemic microenvironment induced the protein levels of all four Class I PI3K isoforms and downstream PI3K/AKT/S6 signaling axis, which was significantly attenuated by IPI-145. To mimic the proliferative state in lymph node pseudofollicles, CLL cells were stimulated to proliferate with CD40L/IL-2/IL-10 and the effect of IPI-145 was measured. Both pAKT and Ki-67 expression were markedly inhibited in primary CLL cells at concentrations of IPI-145 in the low nanomolar range (EC50<10nM; n=2), suggesting a potent anti-proliferative effect of IPI-145 on CLL cells in the nodal environment. Given the significant role of the chemo-attractant, SDF-1, in the directed migration of B-cells, chemotaxis assay demonstrated reduction in migration of CLL cells towards SDF-1 in presence of IPI-145 (% control reduction - median 23%; range 2-42%; n=8). Furthermore, IPI-145 treatment enhanced production of reactive oxygen species (n=6). Taken together, these results demonstrate the potential of combined inhibition of the PI3K-δ and -γ isoforms in CLL, and support clinical investigation of IPI-145 in B-cell malignancies, including CLL. Disclosures: Balakrishnan: Infinity Pharmaceuticals Inc: Research Funding. Peluso:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Faia:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Kutok:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. McGovern:Infinity Pharmaceuticals., Inc.: Employment, Equity Ownership. Gandhi:Infinity Pharmaceuticals., Inc: Research Funding.

scholarly journals Duohexabody-CD37, a Novel Bispecific Antibody with a Hexamerization-Enhancing Mutation Targeting CD37, Demonstrates Superior Complement-Dependent Cytotoxicity in Preclinical B-Cell Malignancy Models

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4170-4170
Author(s):  
Simone C. Oostindie ◽  
Hilma J. Van Der Horst ◽  
Marije B. Overdijk ◽  
Kristin Strumane ◽  
Sandra Verploegen ◽  
...  
Keyword(s):  
B Cell ◽  
Research Funding ◽  
Bispecific Antibody ◽  
Lymphocytic Leukemia ◽  
Single Point Mutation ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Healthy Human ◽  
Complement Dependent Cytotoxicity ◽  
Equity Ownership

Abstract CD37 is a tetraspanin plasma membrane protein abundantly expressed on B-cells and represents a promising therapeutic target for the treatment of B-cell malignancies. Although complement-dependent cytotoxicity (CDC) has proven to be a powerful Fc-mediated effector function for killing hematological cancer cells, CD37 antibody-based therapeutics currently in clinical development are poor inducers of CDC. Here we present DuoHexaBody-CD37, a novel humanized IgG1 bispecific antibody targeting two different CD37 epitopes, with an E430G hexamerization-enhancing mutation, for the potential treatment of B-cell malignancies. The natural process of antibody hexamer formation through intermolecular Fc-Fc interactions between IgG molecules after cell surface antigen binding can be improved by introducing a single point mutation such as E430G in the IgG Fc domain, thereby facilitating more efficient C1q binding and complement activation (Diebolder et al., Science 2014; de Jong et al., PLoS Biol 2016). The hexamerization-enhancing mutation E430G was introduced into two humanized CD37 monoclonal antibodies (mAbs) that bind non-overlapping CD37 epitopes. Different antibody formats and combinations, including the single antibodies, combinations of the mAbs and bispecific mAbs were tested for their capacity to induce CDC and antibody-dependent cellular cytotoxicity (ADCC). The bispecific hexamerization-enhanced antibody variant DuoHexaBody-CD37, showed superior CDC activity compared to the single hexamerization-enhanced mAbs and the combination thereof, both in vitro over a range of different B-cell lines, and ex vivo in tumor cell samples obtained from patients with chronic lymphocytic leukemia (CLL). In a CDC assay using tumor cells obtained from a relapsed/refractory CLL patient who received prior treatment with rituximab, ibrutinib and idelalisib, DuoHexaBody-CD37 induced almost complete lysis (84% lysis at a concentration 100 µg/mL), thereby outperforming the single HexaBody molecules (15% and 23% lysis) and the combination (57%) (Figure 1). In addition to its potent CDC activity, DuoHexaBody-CD37 was also capable of inducing potent ADCC of Daudi cells (EC50 = 12.3 ± 9.5 ng/mL), as assessed using peripheral blood mononuclear cells from 8 healthy human donors in a standard chromium release assay. In assays using whole blood from 6 healthy human donors, DuoHexaBody-CD37 showed efficient B-cell binding and potent and specific depletion of the B-cell population (98% ± 1.3% depletion at 10 µg/mL, EC50 = 0.85 ± 0.284 µg/mL). Furthermore, DuoHexaBody-CD37 induced significant inhibition of tumor growth in vivo in Daudi-luc Burkitt's lymphoma and JVM-3 CLL mouse xenograft models, at doses as low as 0.1 and 1 mg/kg (p<0.05), respectively. In summary, we present a novel therapeutic antibody that, for the first time, combines proprietary DuoBody® and HexaBody® platforms. DuoHexaBody-CD37 induced highly potent CDC and efficient ADCC in preclinical models, suggesting that DuoHexaBody-CD37 may serve as a potential therapeutic mAb for the treatment of human B-cell malignancies. Disclosures Oostindie: Genmab: Employment, Equity Ownership. Van Der Horst:Genmab: Research Funding. Overdijk:Genmab: Employment, Equity Ownership. Strumane:Genmab: Employment, Equity Ownership. Verploegen:Genmab: Employment, Equity Ownership. Lindorfer:Genmab: Research Funding. Cook:Genmab: Research Funding. Chamuleau:Gilead: Research Funding; BMS: Research Funding; celgene: Research Funding; Genmab: Research Funding. Mutis:Gilead: Research Funding; Celgene: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genmab: Research Funding; Novartis: Research Funding; OnkImmune: Research Funding. Schuurman:Genmab: Employment, Other: Warrants. Sasser:Genmab: Employment, Equity Ownership. Taylor:Genmab: Research Funding. Parren:Genmab: Equity Ownership; Lava Therapeutics: Employment. Beurskens:Genmab: Employment, Equity Ownership. Breij:Genmab: Employment, Equity Ownership.

A Phase 2 Study of Idelalisib Monotherapy in Previously Untreated Patients ≥65 Years with Chronic Lymphocytic Leukemia (CLL) or Small Lymphocytic Lymphoma (SLL)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1986-1986 ◽  
Author(s):  
Andrew D. Zelenetz ◽  
Nicole Lamanna ◽  
Thomas J. Kipps ◽  
Steven E. Coutre ◽  
Susan O'Brien ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Lymphoid Tissues ◽  
Small Lymphocytic Lymphoma ◽  
Employment Equity ◽  
Treatment Naïve ◽  
Equity Ownership ◽  
Systemic Therapies

Abstract BACKGROUND: PI3K-delta (δ) is critical for activation, proliferation and survival of B cells and plays a role in homing and retention in lymphoid tissues. PI3Kδ signaling is hyperactive in many B-cell malignancies. Idelalisib (Zydelig, IDELA,), a potent and selective orally administered inhibitor of PI3Kδ, in combination with rituximab weekly x 8 has yielded an ORR of 97% in patients (pts) ≥65 years with previously untreated CLL or SLL (O’Brien, ASCO 2013). This report describes the preliminary experience in treating a similar cohort of pts with IDELA monotherapy. METHODS: Enrollment began in November, 2013. Treatment-naive pts ≥65 yrs with CLL or SLL, requiring treatment per IWCLL 2008 criteria, and with measurable lymphadenopathy, were treated with IDELA 150 mg bid continuously. Response assessment, at pre-determined time points, was investigator determined using either physical exam or CT scans per investigator discretion, using modified IWCLL guidelines (Hallek 2008, Cheson 2012). RESULTS: As of 21 July 2014, 37 pts were enrolled: 78% male; CLL/SLL in 92%/8%; median age 70 years; 73% Rai III or IV; WHO 0-1/2 in 97%/3%. 46% had ≥1 B-symptom. Hepatomegaly and splenomegaly were present in 14% and 57% respectively. Adverse prognostic factors: 14% del(17p) and/or TP53 mutated; 22% del(11q); 41% IGHV unmutated; β-2 microglobulin median 4.35 mg/L (range: 2.1-12.4). The median idelalisib exposure was 4.8 months (range 0.9-8.5). There has been one discontinuation at 3 mo for respiratory distress, assessed as related to a prior condition. The median absolute lymphocyte count was 59.7 K/µl (range: 0.8-294) at baseline peaking at 100 K/µl (range: 2-385) at week 4. 27 pts were evaluable for response, having reached the first evaluation time point of 8 weeks. Of these 27, the ORR was 81% with 9 (33%) PR and 13 (48%) PR with lymphocytosis. Splenomegaly has responded in 88% of 17 evaluable pts and hepatomegaly in 75% of 4 evaluable pts. The most frequent treatment emergent adverse events (TEAE) (% all Grade/% Grade ≥3) were rash (27/3), URI (16/0), constipation (14/0), cough (14/0), nausea (11/0), pyrexia (11/0), arthralgia (8/0), back pain (8/0), diarrhea (8/3), and pneumonia (8/5). Pneumonitis was observed in 2 pts (5%), Gr ≥3 in 1(3%). Gr ≥3 treatment emergent lab abnormalities included transaminase elevation (8%), anemia (5%), and neutropenia (20%); there was no Gr ≥3 thrombocytopenia. One pt had a TEAE leading to dose reduction. CONCLUSIONS: IDELA has substantial single agent activity in treatment-naïve pts with CLL or SLL. Early lymphocytosis is observed with monotherapy in this population, as opposed to an attenuation of lymphocytosis seen in the earlier cohort treated with IDELA plus weekly rituximab. IDELA was well tolerated and had a manageable safety profile in this preliminary analysis. Disclosures Zelenetz: Gilead Sciences: Research Funding. Off Label Use: Zydelig is a kinase inhibitor indicated for the treatment of patients with: 1) Relapsed chronic lymphocytic leukemia (CLL), in combination with rituximab, in patients for whom rituximab alone would be considered appropriate therapy due to other co-morbidities; 2) Relapsed follicular B-cell non-Hodgkin lymphoma (FL) in patients who have received at least two prior systemic therapies; and 3) Relapsed small lymphocytic lymphoma (SLL) in patients who have received at least two prior systemic therapies.. Lamanna:Gilead Sciences: Research Funding. Kipps:Gilead Sciences: Research Funding. Coutre:Gilead Sciences: Research Funding. O'Brien:Gilead Sciences: Research Funding. Aiello:Gilead Sciences: Employment, Equity Ownership. Cho:Gilead Sciences: Employment, Equity Ownership. Dubowy:Gilead Sciences: Employment, Equity Ownership. Flinn:Gilead Sciences: Research Funding.

Correlation Between Serum Ofatumumab Concentrations, Baseline Patient Characteristics and Clinical Outcomes in Patients with Fludarabine-Refractory Chronic Lymphocytic Leukemia (CLL) Treated with Single-Agent Ofatumumab.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3433-3433 ◽  
Author(s):  
Anders Österborg ◽  
Birgitte Biilmann Ronn ◽  
Roxanne C Jewell ◽  
Thomas J Kipps ◽  
Jiri Mayer ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Pivotal Trial ◽  
Employment Equity ◽  
Baseline Factors ◽  
Equity Ownership ◽  
Univariate Analyses

Abstract Abstract 3433 Poster Board III-321 Introduction Monoclonal antibody (mAb) therapies represent an important clinical advance for patients (pts) with CLL, yet little is known about the pharmacokinetics (PK) and pharmacodynamics of mAb therapy in these pts. Ofatumumab is a human mAb targeting a membrane-proximal small-loop epitope on CD20 and mediates efficient complement-dependent cytotoxicity in vitro. Ofatumumab is being evaluated in a pivotal trial for pts with fludarabine-refractory CLL also refractory to alemtuzumab (FA-ref; n=59) or less suitable for alemtuzumab due to bulky (>5 cm) lymphadenopathy (BF-ref; n=79). Overall response rate (ORR; primary endpoint) was 58% in FA-ref and 47% in BF-ref pts at an interim analysis; median progression-free survival (PFS) was 5.7 and 5.9 months, respectively. We evaluated relationships between baseline factors and ofatumumab PK and between PK parameters and treatment outcomes from the pivotal trial. Patients and Methods Pts received 8 weekly infusions of ofatumumab followed by 4 monthly infusions (Dose 1, 300 mg; Doses 2-12, 2000 mg). Response (1996 NCI-WG criteria) was assessed by an Independent Review Committee over 24 weeks of therapy. Blood samples for PK analysis were collected at Dose 1, Dose 8 (last weekly dose), and Dose 12 (last monthly dose). A population PK model was employed that included data from a previous study (Coiffier et al, Blood 2008;111:1094). For Dose 1, Cmax was determined; for Doses 8 and 12, Cmax, Cmin, AUC, clearance (CL), volume of distribution (Vss) and t½ were determined. The relationships between baseline pt characteristics and disease factors and PK parameters were evaluated by multivariate regression analysis. Associations between PK and ORR or PFS were explored using univariate and multivariate logistic regression or Cox regression analyses. Results 90% of the 154 pts received 8 weekly infusions of ofatumumab and 55% received all 12 infusions. PK parameters were similar between FA-ref and BF-ref pts. In multivariate analysis, higher Cmax at Dose 1 was significantly associated with lower % of bone marrow infiltration (p<0.001), lower Rai stage (p=0.002), lower lymphocyte count (p=0.006), smaller BSA (p<0.001) and lower total bilirubin (p=0.013). The majority of responders and non-responders were still receiving treatment at Dose 8; thus, this dose represents an informative time point for analysis. Baseline factors that influenced PK parameters at Dose 8 are shown in the table. Based on univariate analyses, higher Cmax and Cmin at Dose 8 were associated with increased likelihood of response (Table); in addition, significantly higher Cmax, Cmin and AUC were observed in responders versus non-responders (p<0.05 for each; data not shown). Higher Cmax, AUC and Cmin and lower CL at both Doses 8 and 12 were significantly correlated with longer PFS (p<0.05 for each). Based on exploratory multivariate analyses, PK parameters were not independent predictors of ORR or PFS. Conclusions These data demonstrate that baseline factors reflecting disease burden significantly influenced ofatumumab PK. Additionally, higher serum concentrations of ofatumumab at Doses 8 and 12 were associated with positive clinical outcomes in univariate analyses. The pivotal study is ongoing, and further analyses of associations between disease-related factors, PK and treatment response will be performed at study completion. Such analyses will help us to better understand the response kinetics of biological therapy and to optimize the dose. Disclosures Österborg: Celgene: Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Research Funding. 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). Biilmann Ronn:Genmab: Employment. Jewell:GlaxoSmithKline: Employment, Equity Ownership. Kipps:Physicians' Educational Resource, Educational Concepts: Speakers Bureau; Genmab, Abbott Industries, Celgene, Biogen Idec, Cephalon, sanofi-aventis, Medimmune, Memgem, Genentech: Research Funding. Mayer:GlaxoSmithKline: Consultancy. Stilgenbauer:GlaxoSmithKline, Genmab: Consultancy, Honoraria, Research Funding. Hellmann:Novartis, BMS: Consultancy, Honoraria. Robak:GlaxoSmithKline, Roche: Advisory Board, Research Funding. Furman:GlaxoSmithKline: Consultancy, Speakers Bureau. Hillmen:GlaxoSmithKline: Consultancy, Honoraria for Advisory Boards. Trneny:GlaxoSmithKline: Honoraria. Padmanabhan:GlaxoSmithKline: Consultancy, Honoraria; Celgene, Genentech: Consultancy. Kozak:GlaxoSmithKline, Amgen: Consultancy. Chan:GlaxoSmithKline: Employment. Arning:GlaxoSmithKline: Employment, Equity Ownership. Losic:Genmab: Employment, Stock Ownership. Davis:GlaxoSmithKline: Employment, Stock ownership. Wilms:Genmab: Employment, Equity Ownership. Russell:Genmab: Employment, Equity Ownership. Wierda:Genmab, GlaxoSmithKline: Honoraria, Research Funding.

scholarly journals Role of NFAT in Chronic Lymphocytic Leukemia and Other B-Cell Malignancies

2021 ◽  
Vol 11 ◽  
Author(s):  
Ilenia Sana ◽  
Maria Elena Mantione ◽  
Piera Angelillo ◽  
Marta Muzio
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Therapeutic Potential ◽  
Cell Receptor ◽  
Distinct Pattern ◽  
B Cell Receptor ◽  
Lymphocytic Leukemia ◽  
B Cell Malignancies ◽  
Activated T Cells ◽  
Inflammatory Microenvironment

In recent years significant progress has been made in the clinical management of chronic lymphocytic leukemia (CLL) as well as other B-cell malignancies; targeting proximal B-cell receptor signaling molecules such as Bruton Tyrosine Kinase (BTK) and Phosphoinositide 3-kinase (PI3Kδ) has emerged as a successful treatment strategy. Unfortunately, a proportion of patients are still not cured with available therapeutic options, thus efforts devoted to studying and identifying new potential druggable targets are warranted. B-cell receptor stimulation triggers a complex cascade of signaling events that eventually drives the activation of downstream transcription factors including Nuclear Factor of Activated T cells (NFAT). In this review, we summarize the literature on the expression and function of NFAT family members in CLL where NFAT is not only overexpressed but also constitutively activated; NFAT controls B-cell anergy and targeting this molecule using specific inhibitors impacts on CLL cell viability. Next, we extend our analysis on other mature B-cell lymphomas where a distinct pattern of expression and activation of NFAT is reported. We discuss the therapeutic potential of strategies aimed at targeting NFAT in B-cell malignancies not overlooking the fact that NFAT may play additional roles regulating the inflammatory microenvironment.

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 Improvements in Health-Related Quality of Life and Symptoms in Patients with Previously Untreated Chronic Lymphocytic Leukemia: Results from the Phase II GIBB Study of the Combination of Obinutuzumab and Bendamustine

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 683-683
Author(s):  
Jeffrey P. Sharman ◽  
Habte Yimer ◽  
Michael Boxer ◽  
Nicholas Di Bella ◽  
Sunil Babu ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Chronic Lymphocytic Leukemia ◽  
Research Funding ◽  
Lymphocytic Leukemia ◽  
Induction Treatment ◽  
Future Health ◽  
Employment Equity ◽  
Equity Ownership ◽  
Eortc Qlq

Abstract Introduction: Maintenance and/or improvements in health-related quality of life (HRQoL) are important in patients with chronic lymphocytic leukemia (CLL). GIBB (NCT02320487) is an ongoing, open-label, single-arm Phase II study of the combination of obinutuzumab (GA101; G) and bendamustine (B) (BG) in patients with previously untreated CLL. A previous report from the GIBB study demonstrated an investigator-assessed objective response rate of 89.2%, a complete response rate of 49.0%, and no unexpected safety signals with BG (Sharman et al. ASCO 2017). Here, we present the HRQoL data from GIBB. Methods: In the GIBB trial, patients received BG by intravenous infusion over six 28-day cycles: obinutuzumab 100mg on Day (D)1, 900mg on D2, and 1000mg on D8 and D15 of Cycle 1, then 1000mg on D1 of Cycles 2-6; B 90mg/m2 on D2-3 of Cycle 1, and on D1-2 of Cycles 2-6. The European Organisation for Research and Treatment of Cancer Quality of Life - Core (EORTC QLQ-C30) questionnaire includes a global health status measure, 5 functional scales (physical, emotional, cognitive, social, and role functioning), 8 symptom scales/items (fatigue, nausea and vomiting, pain, dyspnea, insomnia, appetite loss, constipation, and diarrhea), and an item on financial difficulties (Aaronson et al. J Natl Cancer Inst 1993). The EORTC Quality of Life Questionnaire-Chronic Lymphocytic Leukemia 16 (QLQ-CLL16) is a 16-item module, specific to CLL, containing 4 multi-item scales (fatigue, treatment side effects, disease symptoms, and infection) and 2 single items (social activities and future health worries; EORTC website, accessed July 25, 2017). Both questionnaires were completed by patients on D1 of Cycles 1 (baseline), 3, and 6, at the end of induction treatment (defined as +28 days from D1 of Cycle 6 or early treatment termination visit), at the response visit (defined as 2-3 months after the end of induction treatment, for all patients who received study treatment and had not experienced disease progression), and every 3 months thereafter at follow-up visits. HRQoL scores were linear transformed to a 0-100 point scale. Mean baseline scores and mean score changes at each visit were evaluated. A threshold of ≥10-point change in score represents a clinically meaningful difference. Results: Of 102 patients enrolled in the trial, 98 completed a questionnaire at baseline and at least one other questionnaire during a follow-up visit. Questionnaire completion rates were 86.7%, 77.6%, 80.6%, and 86.7% at Cycles 3, 6, at the end of induction treatment, and at the response visit, respectively. Median age was 61 years and 68.4% of patients were male. According to the EORTC QLQ-C30 (Figure 1), clinically meaningful improvements were observed for global health status at the response visit, and for role functioning at the end of induction treatment and at the response visit. A trend was observed for improvement in emotional functioning. The greatest improvement in HRQoL score was observed for fatigue (mean baseline score: 37.64), with mean changes from baseline of −4.01, −5.48, −11.67, and −16.34 at Cycles 3, 6, at the end of induction treatment, and at the response visit, respectively. Improvements were also observed for insomnia (mean baseline score: 33.33), with mean changes from baseline of −6.59, −9.09, −9.7, and −10.98, respectively. There was no worsening in other patient-reported symptoms or functional status over time. Similarly, with the EORTC QLQ-CLL16 (Figure 2), clinically meaningful improvements in symptoms were observed for fatigue, disease symptoms, and future health worries during treatment, at the end of induction treatment and/or at the response visit. The greatest change at the response visit was observed for fatigue (−21.23) and future health worries (−20.24). A positive trend was also observed for improvements in the social activities scale. Conclusions: We previously reported that BG is an effective regimen for first-line treatment of CLL with no unexpected safety signals. In addition, the HRQoL data from the GIBB trial suggest that BG treatment improves patient HRQoL. Several clinically meaningful improvements were observed in HRQoL, including global health status, functioning, symptoms, and future health worries at the time of the response visit. Disclosures Sharman: Acerta: Consultancy, Research Funding; TG Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Research Funding; Gilead: Consultancy, Research Funding; Genentech: Consultancy, Honoraria, Other: GIBB is sponsored by Genentech Inc. Third-party editorial support, under the direction of Anthony Masaquel, was provided by Lynda McEvoy of Gardiner-Caldwell Communications, and was funded by F. Hoffmann-La Roche Ltd, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Yimer: Juno pharma: Equity Ownership; Bellucum Pharma: Equity Ownership. Babu: Alexion: Speakers Bureau; Abbvie: Consultancy. Li: Genentech: Employment, Equity Ownership. Mun: Genentech: Employment, Equity Ownership. Trask: Genentech: Employment, Other: stock. Masaquel: Genentech Inc.: Employment, Other: I Receive Roche stock options. Reyes: Genentech Inc.: Employment, Equity Ownership.

Ibrutinib Plus Bendamustine/Rituximab (BR) Is Associated with Greater Reductions in Fatigue Than Placebo Plus BR Among Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia and Fatigue

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 267-267
Author(s):  
Shana Traina ◽  
Graeme Fraser ◽  
Paula Cramer ◽  
Rodrigo Santucci Silva ◽  
Sebastian Grosicki ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Research Funding ◽  
Group Performance ◽  
Eastern Cooperative Oncology Group ◽  
Lymphocytic Leukemia ◽  
Employment Equity ◽  
Fatigue Score ◽  
Travel Grant ◽  
Equity Ownership ◽  
Over Time

Abstract Introduction: Patients with chronic lymphocytic leukemia (CLL) may have reduced health-related quality of life (HRQL) such as severe fatigue during the course of their disease and its treatment. While current treatments aim to increase progression-free survival, it is also important to maintain good HRQL for as long as possible. Methods: Ibrutinib, a first-in-class, once-daily, oral, covalent inhibitor of Bruton's tyrosine kinase, is approved in patients with previously treated CLL and in patients with CLL with del17p, and has recently been shown to reduce the risk of disease progression or death by 80% when added to standard chemoimmunotherapy with BR. In this randomized, double-blind, placebo-controlled, phase 3 study, where patients with active CLL following ≥ 1 prior therapy were randomized 1:1 to receive BR (≤ 6 cycles) with either ibrutinib (420 mg daily) (n = 289) or placebo (n = 289), HRQL and fatigue data were examined. Measures included the FACIT-Fatigue, EORTC QLQ-C30-CLL16, and EQ-5D-5L, which capture general physical and emotional impacts of disease and treatments as well as CLL-specific symptoms. Because examination of mean values may obscure meaningful changes in outcomes, fatigue scores were also examined by baseline quartile with respect to clinical, sociodemographic, and HRQL factors as well as for change over time. Individual CLL symptom items were also examined. The association between changes in hemoglobin levels and fatigue was also examined. Results: Of the 578 patients enrolled, 540 (93%) provided FACIT-Fatigue responses at baseline. No notable mean changes from baseline over time were observed in any HRQL scores within or between the treatment groups. Those in the lowest fatigue score quartile (ie, worst baseline fatigue) were more likely to have an Eastern Cooperative Oncology Group performance score of 1, be in a later stage of disease, have more cytopenias, a greater number of prior therapies, and worse HRQL. Among those with the worst baseline fatigue, unadjusted results indicate apparent improvements in fatigue score over time for both treatments during the first 6 cycles of BR therapy, and subsequently greater continued improvements in fatigue were observed with ibrutinib + BR versus placebo + BR (p < 0.05 at cycle 10) (Figure 1). Similarly, for those with the worst baseline fatigue, mean hemoglobin values appear to increase over time after cycle 2, with comparable changes in each arm (Figure 2). In addition, of the patients who reported feeling ill or unwell at baseline (item 38 on CLL16), a greater proportion reported a return to wellness with ibrutinib + BR (40.0%) versus placebo + BR (27.3%) at cycle 10. This pattern was consistently observed from cycle 2 through cycle 19. Conclusions: These data suggest that addition of ibrutinib to BR is not associated with a negative impact on HRQL and that, among patients with the worst fatigue at baseline, ibrutinib appears to be associated with greater reductions in fatigue versus placebo. Improvements in fatigue appear to be consistent with improvements in hemoglobin and improvements in CLL disease status. Disclosures Traina: Janssen: Employment. Fraser:Hoffman LaRoche: Consultancy, Honoraria; Janssen: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding. Cramer:Astellas: Other: Travel grant; Mundipharma: Other: Travel grant; Glaxo Smith Klein/Novartis: Research Funding; Janssen: Other: Travel grant, Research Funding, Speakers Bureau; Hoffman LaRoche: Other: Travel grant, Research Funding, Speakers Bureau; Gilead: Other: Travel grant, Research Funding. Santucci Silva:Novartis: Other: Travel reimbursement; Merck: Research Funding; Celgene: Research Funding; GSK: Research Funding; Janssen: Other: Travel reimbursement, Research Funding; Hoffman LaRoche: Other: Travel reimbursement, Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Mahler:Janssen: Employment, Other: Travel reimbursement. Salman:Janssen/J&J: Employment, Equity Ownership. Howes:Janssen/J&J: Employment, Equity Ownership.

scholarly journals Targeted Alpha Therapy with 212Pb-NNV003 for the Treatment of CD37 Positive B-Cell Chronic Lymphocytic Leukemia (CLL) and Non-Hodgkin Lymphoma (NHL)

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4422-4422
Author(s):  
Amal Saidi ◽  
Astri Maaland ◽  
Julien Torgue ◽  
Helen Heyerdahl ◽  
Jostein Dahle
Keyword(s):  
B Cell ◽  
Intravenous Dose ◽  
Lymphocytic Leukemia ◽  
Single Intravenous Dose ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Non Hodgkin Lymphoma ◽  
Equity Ownership ◽  
Daudi Cells ◽  
Alpha Therapy

Abstract Background Each year more than 90,000 cases of chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL) are expected in the US. The standard of care is immuno-chemotherapy with alkylating agents in combination with an anti-CD20 monoclonal antibody (mAb). While immuno-chemotherapy regimens are initially effective in inducing responses, most patients inevitably relapse and the same therapies show decreasing efficacy with repeated administration. In recent years, CD37 has been considered as a target for B-cell malignancies. CD37 is strongly and selectively expressed on the surface of mature B lymphocytes and B-cell malignancies. Therapies targeting CD37 expressing cells may become a useful alternative to CD20 targeting agents. Alpha-emitting radionuclides have demonstrated good potential for cancer targeted therapies because of efficient energy deposition along the short alpha track (50-100 µm). The absorbed energy cause irreparable DNA double-strand breaks and localized cytotoxicity while sparing surrounding healthy tissues. We have developed a targeted alpha therapy (TAT) where the CD37-specific antibody NNV003 is coupled to the alpha-particle-emitting radioisotope 212Pb. Materials and Methods Dose-dependent efficacy and tolerability of a single-dose 212Pb-NNV003 treatment was evaluated using escalating activity levels in human disseminated models of Burkitt's lymphoma (Daudi) and CLL (MEC-2). 10 million Daudi cells or 2.5 million MEC-2 cells were intravenously injected in CB17-SCID or R2G2 mice and 212Pb-NNV003 was given two days later. Unspecific, 212Pb-labeled antibody was used as control. A study of the tolerability of 212Pb-NNV003 was performed in R2G2 mice without tumor prior to the efficacy studies. Results 212Pb-NNV003 displays a favorable toxicity profile in tumor-free mice single intravenous dose injections up to 15 µCi showing 100 % survival 4 weeks post-injection. No acute hematological toxicity was observed and animals who received 5, 10 or 15 μCi doses of 212Pb-NNV003 presented only a slight initial reduction in their platelets (PLT) counts which was fully recovered by 20 days after injection. A single intravenous dose of 10, 15 or 20 µCi of 212Pb-NNV003 lead to 70 %, 90 % and 100 % of mice injected with MEC-2 cells being tumor free 20 weeks post cell injection (Figure 1). Control animals that received saline, cold antibody or 212Pb-cetuximab presented a median survival of 4.9, 5.4 and 9.3 weeks, respectively. A single intravenous dose of 2.5, 5 and 7.5 µCi 212Pb-NNV003 lead to over 80% tumor-free mice injected with Daudi cells 15 weeks post cell injection (Figure 2). Control animals that received saline, cold antibody or 212Pb-cetuximab presented a median survival of 7, 7.8 and 7.7 weeks, respectively. Conclusion The results of preclinical studies suggest that TAT using 212Pb-NNV003 is a safe and effective method for the treatment of CD37 positive CLL and NHL. Disclosures Saidi: Orano Med: Employment. Maaland:Nordic Nanovector: Employment. Torgue:Orano Med: Employment, Membership on an entity's Board of Directors or advisory committees. Heyerdahl:Nordic Nanovector: Employment, Equity Ownership. Dahle:Nordic Nanovector ASA: Employment, Equity Ownership, Patents & Royalties.

scholarly journals Whole-Exome Sequencing Revealed No Recurrent Mutations within the PI3K Pathway in Relapsed Chronic Lymphocytic Leukemia Patients Progressing Under Idelalisib Treatment

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2770-2770 ◽  
Author(s):  
Paolo Ghia ◽  
Viktor Ljungström ◽  
Eugen Tausch ◽  
Andreas Agathangelidis ◽  
Annika Scheffold ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Research Funding ◽  
Somatic Mutations ◽  
Lymphocytic Leukemia ◽  
Employment Equity ◽  
Phase 3 ◽  
Whole Exome ◽  
Equity Ownership

Abstract Introduction: Idelalisib (IDELA) is an ATP-competitive, reversible, and selective small molecule inhibitor of the delta isoform of phosphatidylinositol 3-kinase (PI3Kδ) approved for the treatment, in combination with rituximab, of patients with relapsed chronic lymphocytic leukemia (CLL). In the relapsed CLL randomized, controlled trials, IDELA + rituximab showed high response rates with improved progression-free and overall survival as compared with placebo + rituximab. While IDELA therapy has significant efficacy, disease progression after response occurs, indicating that escape mechanisms may develop. However, the molecular basis for relapse or progressive disease (PD) in CLL patients treated with IDELA has not yet been characterized. Methods: Peripheral blood mononuclear cells (PBMCs) were collected from 13 CLL patients enrolled in the phase 3 studies; NCT01539512 (study 116; IDELA + rituximab vs placebo + rituximab), 116 extension study NCT01539291 (study 117) and NCT01659021 (study 119; IDELA + ofatumumab). Sample selection criteria included treatment period of at least 180 days (range: 243-703 days), achieving at least partial nodal response followed by PD, PD did not occur within a drug interruption window, PD was not associated with Richter's transformation, and PBMC samples were available from both baseline and time of PD. Whole-exome sequencing (WES) was conducted on the matched samples from 13 subjects fitting the above criteria. In 6/13 cases, DNA was available from CD19+/CD5+ enriched tumor cells, and neutrophils or T-lymphocytes served as a source of germline DNA. These 6 patients were considered as a discovery set for mutational analysis. Established bioinformatics tools were used for detection of somatic mutations and for the comparison of baseline and PD samples. Results: Baseline clinical patient profiles indicated that 12 of 13 patients with PD had unmutated IGHV genes and 8 patients carried TP53 aberrations (ie, 17p deletion and/or TP53 mutation). WES resulted in a mean read depth of 106X within the targeted coding region across samples. In the discovery set, on average 25 somatic mutations (range: 4-44) at baseline and 32 mutations (range: 15-81) at progression were identified. By comparing baseline and PD samples, we identified 88 PD-associated mutations. These specific mutations were tested for in a complete set of 13 patient samples; however, no recurrent progression-associated mutations were identified in more than 1 patient. In particular, no progression-associated mutations were identified in the PI3K signaling pathway or in any other related pathway. Conclusion: Across 3 phase 3 studies in relapsed CLL, WES on 13 samples from patients with PD while on IDELA treatment were evaluated. This analysis detected no relapse-associated mutations in common across this patient set; in particular, no mutations were identified in the drug-binding site (ie, "gateway mutation") or in any other related signaling pathway. Based on these results, we conclude there is no common mutational mechanism of IDELA resistance in this patient group. Disclosures Ghia: Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Honoraria, Research Funding; Adaptive: Consultancy; Abbvie: Consultancy, Honoraria. Tausch:Gilead: Other: Travel support, Speakers Bureau; Celgene: Other: Travel support; Amgen: Other: Travel support. Owen:Roche: Honoraria, Research Funding; Pharmacyclics: Research Funding; Celgene: Honoraria, Research Funding; Abbvie: Honoraria; Lundbeck: Honoraria, Research Funding; Novartis: Honoraria; Janssen: Honoraria; Gilead: Honoraria, Research Funding. Barrientos:Gilead: Consultancy, Research Funding; Janssen: Consultancy; AbbVie: Consultancy, Research Funding. Munugalavadla:Gilead Sciences: Employment, Equity Ownership. Degenhardt:Gilead Sciences: Employment, Equity Ownership. Kim:Gilead Sciences: Employment, Equity Ownership. Dubowy:Gilead Sciences: Employment, Equity Ownership. Dreiling:Gilead Sciences: Employment, Equity Ownership. Rosenquist:Gilead Sciences: Speakers Bureau. Stilgenbauer:Hoffmann-La Roche: Consultancy, Honoraria, Other: Travel grants , Research Funding; AbbVie: Consultancy, Honoraria, Other: Travel grants, Research Funding; GSK: Consultancy, Honoraria, Other: Travel grants , Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: Travel grants , Research Funding; Janssen: Consultancy, Honoraria, Other: Travel grants , Research Funding; Mundipharma: Consultancy, Honoraria, Other: Travel grants , Research Funding; Celgene: Consultancy, Honoraria, Other: Travel grants , Research Funding; Amgen: Consultancy, Honoraria, Other: Travel grants, Research Funding; Novartis: Consultancy, Honoraria, Other: Travel grants , Research Funding; Sanofi: Consultancy, Honoraria, Other: Travel grants , Research Funding; Genzyme: Consultancy, Honoraria, Other: Travel grants , Research Funding; Genentech: Consultancy, Honoraria, Other: Travel grants , Research Funding; Gilead: Consultancy, Honoraria, Other: Travel grants , Research Funding; Boehringer Ingelheim: Consultancy, Honoraria, Other: Travel grants , Research Funding.

Target Engagement, Pathway Inhibition, and Efficacy Of The Bruton’s Tyrosine Kinase (Btk) Inhibitor CC-292

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4169-4169 ◽  
Author(s):  
Daniel W Pierce ◽  
Sabine Ponader ◽  
Kumudha Balakrishnan ◽  
Varsha Gandhi ◽  
William G. Wierda ◽  
...  
Keyword(s):  
B Cell ◽  
Research Funding ◽  
Phase 1 ◽  
Clinical Activity ◽  
B Cell Malignancies ◽  
Employment Equity ◽  
Post Dose ◽  
Equity Ownership

Abstract Introduction The B-cell receptor (BCR) and its downstream effectors have emerged as important therapeutic targets in B-cell malignancies. CC-292 is a novel, potent, covalent, and highly selective inhibitor of Btk (IC50apparent of 0.5 nM, kinact/KI ratio of 7.69 × 104 M-1s-1), that does not appreciably inhibit other kinases involved in BCR signaling (eg, IC50 Lyn kinase, 4401 nM) (Evans et al., J Pharmacol Exp Ther. 2013). Here, we report preclinical characterization and clinical data in CLL from a single-agent phase 1 dose-escalation trial of CC-292 in B-cell malignancies, with a focus on how target engagement and downstream events correlate with clinical activity. Results Pharmacodynamic effects of Btk inhibition by CC-292 can be monitored by occupancy of the Btk catalytic site, Btk autophosphorylation on Y223, and downstream phosphorylation of Plc-γ2 and Erk. We developed a sensitive (10 pg/mL lower limit of quantification) and quantitative assay to measure covalent binding of CC-292 to Btk (Evans et al., J Pharmacol Exp Ther. 2013), as well as Western and novel phos-flow assays to probe downstream signal transduction. These methods showed that CC-292 treatment blocks Btk autophosphorylation and downstream pathway activation in both tumor cells and human peripheral blood mononuclear cells (PBMCs). The extent of CC-292 binding to Btk correlated with its in vitro and in vivo effects. The occupancy assay demonstrated that CC-292 effectively targets Btk in tumor cell lines, PBMCs, spleen, and lymph nodes (LNs) in animal models, and in PBMC and lymph node samples from clinical trial subjects. In rats and non-human primates treated with CC-292, Btk occupancy in spleen and LNs was dose-dependent. Measured occupancy in rat spleen and axillary, mesenteric, and superficial cervical LNs was 94%, 92%, 90%, and 76% respectively, 4 hours (hrs) after a single 30-mg/kg dose. Interim data from the phase 1 CLL trial showed that PBMC Btk was completely occupied in the majority of subjects 4 hrs post-dose with both QD and BID dosing. Twenty-four hrs post-dose at 750 and 1000 mg QD, CC-292 exhibited 83% ± 17% Btk occupancy, whereas with BID dosing at 375 and 500 mg, occupancy was 94% ± 16% at the corresponding time point (12 hrs after the second dose). Thus, while both schedules achieved extensive and sustained Btk occupancy, residual free Btk levels were lower with the BID schedule, offering a rationale for an early trend towards more rapid nodal responses, lymphocytosis, and partial responses on the BID schedule observed to date in the phase 1 study. In the 10 clinical LN biopsies tested to date, no measurable levels of unoccupied Btk have been detected, although Btk protein was present as determined by Western blotting, showing that CC-292 was able to penetrate LNs and inhibit Btk in human subjects as it did in preclinical models. For monitoring downstream signal transduction, we developed reagents and assays including a phos-flow assay based on a novel rabbit monoclonal antibody to detect Btk pY223 levels in PBMC subsets. CC-292 effectively inhibited constitutive and induced phosphorylation of Btk and Plc-γ2 at low nanomolar concentrations. CC-292 also inhibited BCR activation and nurse-like cell–supported survival of CLL cells. Furthermore, CC-292 reduced CLL cell migration and actin polymerization in response to chemokines (CXCL12, CXCL13) and inhibited secretion of the chemokines CCL3 and CCL4 by CLL cells. These chemokines are essential for migration and retention of normal and neoplastic B cells in the marrow and secondary lymphatic tissues. Consistent with this preclinical data, CC-292 treatment resulted in rapid reductions in circulating CCL3 and CCL4 levels. In subjects treated at the 750 mg QD, 1000 mg QD, 375 mg BID, and 500 mg BID dose levels, plasma CCL3 was reduced from 99 ± 16 pg/ml before treatment to 28 ± 5 pg/ml (N = 48, mean ± SEM) at 24 hrs after the first dose, while CCL4 was reduced from 235 ± 59 pg/ml to 74 ± 16 pg/ml (N = 51). Conclusions These data demonstrate that CC-292 achieves significant and durable occupancy of Btk in vitro and in vivo, inhibits Btk-mediated downstream signaling events and chemokine production, and that these preclinical activities have translated into the clinic. Taken together, these results argue that Btk inhibition is necessary and sufficient for clinical activity in CLL. These emerging data support continued development of CC-292 for the treatment of B-cell malignancies. Disclosures: Pierce: Celgene: Employment, Equity Ownership. O'Brien:Genentech: Consultancy, Research Funding; Emergent: Consultancy, Research Funding; CLL Global Research Foundation: Membership on an entity’s Board of Directors or advisory committees; Celgene: Consultancy; Gilead Sciences: Consultancy, Research Funding; Infinity: Consultancy, Research Funding; MorphoSys: Research Funding; Pharmacyclics: Consultancy, Research Funding; Talon: Consultancy, Research Funding; Teva/Cephalon: Consultancy. Heise:Celgene: Employment, Equity Ownership. Nacht:Celgene: Employment, Equity Ownership. Aslanian:Celgene: Employment, Equity Ownership. Liu:Celgene: Employment, Equity Ownership. Hong:Celgene: Employment, Equity Ownership. Wu:Celgene: Employment, Equity Ownership. Zavodovskaya:Celgene: Employment, Equity Ownership. Marine:Celgene: Employment, Equity Ownership. Barnett:Celgene: Employment, Equity Ownership. Nava-Parada:Celgene: Employment, Equity Ownership. Mei:Celgene: Employment, Equity Ownership. Chopra:Celgene: Employment, Equity Ownership. Burger:Pharmacyclics: Research Funding; Gilead: Research Funding. Singh:Celgene: Employment, Equity Ownership.

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