Calistoga Pharmaceuticals Research Articles

LAM-003, a Novel Oral Heat Shock Protein 90 Inhibitor for Treatment of Acute Myeloid Leukemia, Including Wild-Type and FMS-like Tyrosine Kinase 3 (FLT3)-Mutant Disease

Acute myeloid leukemia (AML) remains a disease with high unmet medical need. While most patients respond to initial therapy, few are cured, relapse rates are high, and most patients eventually develop life-threatening complications. FLT3-mutant disease is a particularly aggressive subtype. Recent approval of drugs targeting FLT3-mutant disease have improved short-term outcomes but not all patients respond, and duration of response is limited by secondary mutations that impede FLT3 inhibitor (FLT3i) binding (intrinsic factors) and by secreted stromal factors that activate alternative pro-survival pathways (extrinsic factors). Heat-shock protein 90 (HSP90) is a chaperone protein involved in many cellular processes and inhibition of HSP90 can have pleiotropic effects in targeting cancer cells such as degradation of oncoproteins that drive survival and proteins that mediate protective signaling. Here, we describe the nonclinical activity of LAM-003, an orally bioavailable HSP90 inhibitor (HSP90i) under clinical development for AML. To assess the anti-leukemic activity of LAM-003, we tested a panel of AML cell lines and primary AML samples. LAM-003 inhibited proliferation of both FLT3-mutant and wild-type cell lines, with preferential activity against cells harboring FLT3-ITD (geometric mean FLT3-ITD EC50 = 670 nM [n=8] vs FLT3 WT EC50 = 1400 nM [n=16]). Additionally, we observed that LAM-003 was potent in a subset of the FLT3 WT cells. To explore whether LAM-003 was effective against tumors driven by oncoproteins that are client proteins of HSP90, we focused on AML cells harboring FLT3-ITD. We confirmed that LAM-003 reduced cell surface FLT3-ITD expression and downstream signaling in MV-4-11 and MOLM-13 cells, consistent with HSP90i-mediated degradation of FLT3-ITD. In BA/F3 cells expressing FLT3-ITD with various secondary resistance mutations, we observed that LAM-003 elicited a dose-dependent reduction of FLT3 mutant cell surface expression. Moreover, BA/F3 cells expressing FLT3-ITD and the F691L mutation exhibited the expected resistance to crenolanib, yet LAM-003 retained anti-proliferative activity. Additionally, MOLM-13 cells harboring a FLT3 D835Y mutation demonstrated expected resistance to the FLT3i sorafenib and tandutinib yet remained sensitive to LAM-003. Finally, primary AML blasts harboring a D835 mutation displayed sensitivity to LAM-003 when tested ex vivo. To evaluate the potential of LAM-003 to overcome bone-marrow-stroma-derived resistance, FLT3-ITD AML cell lines (MV-4-11, MOLM-13, MOLM-14) were assayed in unconditioned or stromal-cell-conditioned medium. Conditioned medium dramatically reduced the potency of FLT3i but LAM-003 demonstrated equal potency under both conditions. We also showed that stromal cell co-culture induced FLT3i resistance in MOLM-13 cells whereas LAM-003 retained potent activity. Recognizing that the inherent genetic heterogeneity of AML blasts limits the curative potential of a single drug, we performed in vitro studies to identify drugs that synergize with LAM-003 in 3 FLT3-ITD AML cell lines. Synergy was demonstrated with FLT3i, daunorubicin, azacitidine or cytarabine, with the most robust synergy being observed with venetoclax. Extending the evaluation to AML cells wild type for FLT3 and cell lines from other hematologic indications (multiple myeloma, diffuse large B-cell lymphoma and mantle cell lymphoma), we found that the synergy was not limited to cells harboring FLT3-ITD, but rather correlated with BCL-2 abundance, suggesting a fundamental mechanism of action that depends on BCL-2 family-mediated survival. Mechanistic studies demonstrated that the combination of LAM-003 and venetoclax inhibited AKT-mediated regulation of GSK3B, resulting in MCL-1 degradation. In vivo studies using a MOLM-13 systemic model of FLT3-ITD AML demonstrated that LAM-003 monotherapy significantly improved animal survival and that the combination of LAM-003 and venetoclax significantly prolonged animal survival compared with each single agent. These nonclinical studies demonstrate that LAM-003 exhibits antileukemic activity, overcomes mechanisms of FLT3i resistance and potently synergizes with existing AML drugs. As such, our data provide strong rationale for evaluation of LAM-003 in an ongoing clinical trial in patients with AML (NCT03426605). Disclosures Beeharry: AI Therapeutics: Employment, Equity Ownership. Landrette:AI Therapeutics: Employment. Grotzke:AI Therapeutics: Employment. Gayle:AI Therapeutics: Equity Ownership. Young:AI Therapeutics: Employment, Equity Ownership. Miller:Incuron, Inc.: Consultancy; Cleveland Biolabs, Inc: Employment, Equity Ownership; Calistoga Pharmaceuticals, Inc.: Equity Ownership; AI Therapeutics: Consultancy, Equity Ownership; VelosBio Inc.: Employment, Equity Ownership; Acerta Pharma, Inc.: Equity Ownership. Xu:AI Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Rothberg:AI Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Lichenstein:AI Therapeutics: Employment, Equity Ownership.

Idelalisib Monotherapy and Durable Responses in Patients with Relapsed or Refractory Small Lymphocytic Lymphoma (SLL)

Idelalisib Monotherapy and Durable Responses in Patients with Relapsed or Refractory Small Lymphocytic Lymphoma (SLL)

Prevalence and Prognostic Value of BCL2 and MYC Protein Expression within ABC and GCB Subtypes in Patients with Previously Untreated, Diffuse Large B-Cell Lymphoma: Analysis from the Phase III MAIN Study

Introduction. Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma (NHL). Although more than half of patients are cured with standard immunochemotherapy (R-CHOP) in first-line therapy, the disease relapses or is refractory to R-CHOP in ~40% of cases, with limited options for second-line treatment. Molecular characteristics, including Cell-of-Origin (COO), BCL2 expression and concomitant BCL2/MYC expression, contribute to differences in outcome for DLBCL patients (Alizadeh, Nature 2000, Iqbal Clin Cancer Res. 2011, Johnson JCO. 2012). Understanding these molecular risk factors is potentially of value to guide treatment decisions and optimize therapy. Here, we used assays validated for formalin-fixed, paraffin-embedded (FFPE) specimens to retrospectively assess the prevalence and prognostic value of BCL2 and MYC in patients from MAIN, a Phase III trial that evaluated bevacizumab plus R-CHOP in frontline, CD20-positive DLBCL (NCT00486759). This analysis will help assess markers relevant for risk assessment and may guide use of new investigational agents in DLBCL. Methods. Tissue microarrays (TMAs) from FFPE tumor samples were evaluated using immunohistochemistry (IHC) for BCL2 (clone 124 DAKO), and MYC (clone Y69 Epitomics). FFPE cell pellets from 26 NHL cell lines were also stained as above. BCL2 staining was scored on a 0-3 intensity scale; the BCL2 cutoff was determined by the expression level that conferred sensitivity ( Results. Baseline tissue samples were available from 230/787 (29%) patients from MAIN, with baseline characteristics and survival similar to the overall ITT population. TMAs were available for IHC evaluation in 184/230 (80%) samples, 88/184 (48%) of which were BCL2 positive. BCL2-positivity rates in various sub-sets were: 58% of IPI high, poor prognostic group vs. 41% of IPI low, good prognostic group, and 64% of ABC vs. 40% of GCB samples (Figure 1). BCL2 expression appeared to associate with adverse PFS in the GCB subtype (HR adjusted for IPI, 3.89; 95% CI: 1.30-11.68, Figure 2a) but not in the ABC subtype (HR adjusted for IPI: 0.81; 95% CI: 0.3-2.2, Figure 2b). BCL2 mRNA expression or BCL2 gene rearrangements by FISH showed no association with PFS. Thirty-two of 174 (18%) samples evaluated for MYC and BCL2 by IHC were DP (95% CI: 13%-25%). PFS was similar in non-DP and DP group (HR adjusted by IPI, 0.77; 95% CI: 0.40-1.48), but the DP group appeared to have inferior OS (HR adjusted by IPI, 0.45; 95% CI: 0.22-0.93). These data should be interpreted cautiously due to the small number of PFS/OS events. BCL2 IHC, BCL2 rearrangements and MYC IHC data were available for 40 ABC and 59 GCB samples. DP by IHC was observed in 10/40 (25%) ABC subtype and 10/59 (17%) GCB subtype samples. BCL2 translocations were observed in 6/40 (15%) of ABC, vs. 19/59 (32%) of GCB samples. Conclusions. Using validated assays developed for FFPE tissue testing, we determined the prevalence and prognostic value of BCL2 in a frontline DLBCL population enrolled in a clinical trial. BCL2 expression appeared to be higher in the poor prognostic groups (high IPI and ABC), and appeared to be an independent prognostic factor in the GCB subtype. BCL2 expression, DP and COO may identify patients with DLBCL who could benefit from BCL2 inhibition; the assays employed here are currently in use to evaluate BCL2 as a predictive biomarker for the BCL2 inhibitor venetoclax in lymphoma trials. Disclosures Punnoose:Genentech, Inc.: Employment. Off Label Use: This abstract reports on biomarker analyses using samples taken from previously untreated patients with DLBCL who received bevacizumab in combination with R-CHOP in the MAIN study. Peale:Roche: Equity Ownership; Genentech, Inc.: Employment. Lei:Roche: Employment. Sandmann:F. Hoffmann-La Roche AG: Employment, Equity Ownership. Bourgon:Roche: Equity Ownership; Genentech, Inc.: Employment. Szafer-Glusman:Genentech, Inc.: Employment. Do:Genentech, Inc.: Employment. Salles:Celgene Corporation; Roche: Speakers Bureau; Celgene Corporation; Roche and Gilead Sciences: Research Funding; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy. Seymour:Roche: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: Travel support, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Incyte: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Infinity: Honoraria, Membership on an entity9s Board of Directors or advisory committees; Phebra: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: Travel support, Research Funding, Speakers Bureau; Genentech, Inc.: Membership on an entity9s Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity9s Board of Directors or advisory committees. Trneny:Roche: Consultancy, Membership on an entity9s Board of Directors or advisory committees, Research Funding. Munoz:Roche: Employment, Equity Ownership. Mundt:Roche: Employment.

Idelalisib Treatment Is Associated with Improved Cytopenias in Patients with Relapsed/Refractory iNHL and CLL

BACKGROUNDChronic lymphocytic leukemia (CLL) and indolent non-Hodgkin lymphoma (iNHL) are B-cell malignancies associated with neutropenia, anemia and thrombocytopenia.The etiology of impaired hematopoiesis is not well understood, however the bone marrow leukemia/lymphoma cell infiltrates that often occur with these diseases is thought to contribute. In studies evaluating the selective PI3Kd inhibitor idelalisib (IDL) in B-cell malignancies, hematologic responses across all 3 lineages were observed in a majority of patients (pts) with baseline (BL) cytopenias.This post hoc analysis reports hemogram changes in pts with relapsed or refractory (R/R) CLL/iNHL treated with IDL in two pivotal studies and describes trends in hematologic parameters over time during IDL treatment in pts with or without BL cytopenias.METHODSIn phase 3 study 312-0116 (NCT01539512), frail pts with R/R CLL were randomized to receive a combination of 8 doses of rituximab (R) with IDL 150 mg BID or placebo (P). In phase 2 study 101-09 (NCT01282424), pts with refractory iNHL received IDL 150 mg BID. In both studies, IDL was continued until disease progression (PD) or unacceptable toxicity. Trial inclusion criteria allowed enrollment of pts with BL cytopenias of any grade (CLL) or grade ˂3 (iNHL).Hematologic profiles for pts in each study were categorized as normal or abnormal (any grade of cytopenia) at BL. In the iNHL study, pts with PD at the first assessment were excluded from this analysis to avoid confounding by underlying uncontrolled disease.RESULTSA total of 345 pts participated in the 2 trials. The overall response rates of IDL-treated patients in the CLL and iNHL studies were 81% and 57%, respectively.For pts with CLL on IDL+R (n=110), BL cytopenias (grade ≥1) included anemia (76%), thrombocytopenia (62%), and neutropenia (34%). For pts with iNHL on IDL-mono (n=115), BL cytopenias included anemia (50.4%), thrombocytopenia (64.3%), and neutropenia (75.7%). We present changes in hemoglobin (Hgb), platelet (PLT), or neutrophil (ANC) counts over time (BL, peak, and time to peak) in pts with an abnormal BL hemogram in Table 1.Median hematologic lab values over time were unchanged in pts with normal hemograms at BL. Among patients with BL cytopenia, anemia and thrombocytopenia improved over time in pts with CLL and iNHL while on treatment with IDL. For pts with CLL, the magnitude of improvement was larger for pts in the IDL+R arm compared to those in the P+R arm. For pts in the IDL+R arm, median peak values of Hgb and PLT were observed within 6 months of IDL initiation. For pts with iNHL, median peak values for Hgb and PLT were observed within 3 months. ANC remained stable over time in CLL, and increased in iNHL.CONCLUSIONSIdelalisib treatment was associated with improvement in Hgb and PLT counts in this population of pts with R/R CLL or iNHL. In those pts with BL anemia or thrombocytopenia, peak improvement in Hgb or PLT values occurred early in treatment (≤3 months for iNHL and ≤6 months for CLL). [Display omitted] DisclosuresO'Brien:Gilead: Research Funding. Davies:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Flinn:Cephalon, Inc; Teva Pharmaceutical Industries Ltd; Genentech, inc; Gilead: Research Funding. Gopal:Spectrum, Pfizer, BioMarin, Cephalon/Teva, Emergent/Abbott. Gilead, Janssen., Merck, Milennium, Piramal, Seattle Genetics, Giogen Idec, BMS: Research Funding; Gilead, Spectrum, Pfizer, Janssen, Seattle Genetics: Consultancy; Millennium, Seattle Genetics, Sanofi-Aventis: Honoraria. Kipps:Pharmacyclics Abbvie Celgene Genentech Astra Zeneca Gilead Sciences: Other: Advisor. Salles:Celgene Corporation; Roche and Gilead Sciences: Research Funding; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche: Speakers Bureau. Newcomb:Gilead: Employment. Waldapfel:Gilead: Employment. Zhang:Gilead: Employment. Stilgenbauer:Gilead: Honoraria, Research Funding.

Outcomes in Diffuse Large B-Cell Lymphoma (DLBCL) Patients Relapsing after Autologous Stem Cell Transplantation (ASCT): An Analysis of Patients Included in the Coral Study

Introduction and Methods: Salvage chemotherapy followed by high-dose therapy and autologous stem cell transplantation (ASCT) is standard care for relapsed/refractory DLBCL. In the CORAL study, 477 patients were assigned to one of two salvage regimens (R-DHAP or R-ICE). Only the 240 responding patients underwent per protocol ASCT and were randomly assigned to rituximab or observation. The four-year event-free survival (EFS) post ASCT were 52 and 53% for the rituximab and observation groups, respectively (p=.7). Secondary IPI (sIPI) independently predicted EFS, PFS and OS after ASCT (Gisselbrecht et al, JCO 2010 & 2012). Outcome data are limited in DLBCL patients who relapse after ASCT, with reported overall survival (OS) of 9.9 months in rituximab-pretreated patients (Nagle et al, AJH 2013). To shed more light on outcome and prognostic factor in this population, 75 patients included in the CORAL study who relapsed after scheduled BEAM/ASCT were reviewed.Results:Median time between ASCT scheduled in CORAL and relapse was 7.1 months (range 3.1-61.9) with 32.9% relapsing > 12 months. Median age was 56.1y (range 20.9-67.7), M/F ratio 51/24, sIPI 0-2 in 71.6%, >2 in 28.4%. 49.3% were in the rituximab and 45.3% in the observation arm of the CORAL. All patients had previously received rituximab. Third-line therapy consisted of ICE-type (17.3%), DHAP-type (24%), gemcitabine-containing (28%), CHOP-like (13.3%), and miscellaneous regimens (17.3%). Overall response rate to third-line chemotherapy was 44%, with 32% complete response (CR)/CR unconfirmed (CRu), and 12% PR. Among the 75 patients, 16 (21.6%) could eventually be transplanted 3 ASCT and 13 allogeneic SCT with conditioning regimens including fludarabine. Median OS, calculated from time of relapse until death, was 10.0 months (95% CI 6.6-12.6; min: 0.9-max: 55.2 months; median follow-up: 32.8 months) with an estimated 1-y OS of 39.1%. Median OS was statistically different (p=.0007) according to sIPI at CORAL failure: sIPI 0-2: 12.6 months (1-y OS 51.3%), sIPI > 2: 5.3 months (1-y OS 21.6%, HR 2.805). Median OS in patients achieving CR/CRu, PR, or no response after third-line regimen was 37.7 m (1-y OS 90.5%, p<.0001, HR 0.132), 10.0 m (1-y OS 44.4%, p=.03, HR 0.375), and 6.3 months (1-y OS 13.4%), respectively. Median OS of patients who could eventually be transplanted was 17.4 months (1-y OS 68.2%), as compared to a median OS of 8.0 months in those who were not transplanted (1-y OS 31.2%) with a HR of 0.575 (p=.11). Median OS was particularly dismal among patients who relapsed < 6 months after CORAL-scheduled ASCT (5.7 months, n=28), as compared to those relapsing either > 6 and < 12 months (11.3 months, n=21) or > 12 months after ASCT (12.6 months, p=0.01, fig. 1)). In multivariate Cox analysis (with the following variables entered: age, sex, sIPI, response to third line and time between CORAL ASCT and relapse), sIPI >2 (HR 2.464, p=0.01), achievement of CR (HR 0.1, p<.0001) or PR (HR 0.242, p=0.02), and post-ASCT remission lasting < 6 months (HR 2.270, p=0.05) independently predicted for OS.Conclusions: Overall, the outcome of DLBCL patients relapsing after second-line R-DHAP/R-ICE followed by ASCT is poor. However, prognostic factors predicting better outcome in this group are late (> 6 months) relapse, lower sIPI and achieving at least PR after third-line salvage followed by transplantation. In the transplanted patients (allo SCT or second ASCT) a 2-year OS of 50% was observed. Thus, new salvage regimens can be a bridge to transplantation in patients with late relapse and/or low sIPI,. New drugs improving salvage efficacy are urgently needed, especially for patients relapsing < 6 months following ASCT. [Display omitted] DisclosuresSchmitz:Roche, Takeda, Gillead, Riemser und ctilifesciences: Other: Advisory board, Speakers Bureau. Gill:Sanofi Aventis: Research Funding; Roche: Honoraria; AbbVie: Honoraria; Roche: Research Funding. Milpied:Celgene: Honoraria, Research Funding. Briere:St. Louis Hospital, Paris, France: Employment. Thieblemont:St. Louis Hospital, Paris, France: Employment. Salles:Celgene Corporation; Roche and Gilead Sciences: Research Funding; Celgene Corporation; Roche: Speakers Bureau; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy. Gisselbrecht:roche: Research Funding, Speakers Bureau.

A Multicenter, Case-Control Study Evaluating the Characteristics and Outcome of ITP Patients Refractory to, Rituximab, Splenectomy and Both TPO Receptor Agonists

▪Introduction: Before the emergence of new treatments, refractory immune thrombocytopenia (ITP) was defined as the failure to achieve a minimum response to splenectomy and the requirement of long-term treatments to reduce risk of significant bleeding events. These patients experience a significant morbidity and mortality rate (1). The first aim of this study was to describe the characteristics of patients with multirefractory ITP (multi-ref ITP) according to an updated definition, i.e., patients who failed to respond to splenectomy, monoclonal anti-CD20 antibodies (rituximab, RTX) and both thrombopoietin-receptor agonists (TPO-RAs), as well as to identify associated factors with this phenotype. The second aim was to examine the long-term outcome of these patients.Patients and Methods: We carried out a multicenter retrospective study in France. Inclusion criteria of patients with multi-ref ITP were failure to splenectomy, rituximab and the two marketed TPO-RAs, or presentation of an absolute contraindication to these treatments. Failure to treatment was defined according to standardized international criteria and bleeding score as described by Khellaf et al. Physicians were interviewed and patients' medical charts collected using the standardized form of the Referral Center for Adult ITP. In order to assess the variables associated with multirefractory occurrences, patients with multi-ref ITP were compared with non-multirefractory patients: for each case, 5 controls were randomly selected from the ITP clinical research database at Henri-Mondor Hospital, matched on the year of diagnosis. This database includes all ITP patients followed in the French national center for autoimmune cytopenias. Univariate and multivariate conditional logistic regression models were performed (backward procedure, α=5%).Results: Thirty-seven patients (12 men/25 women) with multi-ref ITP and 183 controls were included in the study. Patients with multi-ref ITP have presented more initial bleeding symptoms than controls (75.6% vs 52.75%, p=.012)), had more frequently secondary ITP (35% vs 8.74%, p<.001), presented more clinical/biological auto-immune abnormalities (59.46% vs 28.42%, p=0008) and had more frequently a monoclonal gammopathy of undetermined significance than controls (19% vs 2.89%, p<.001). Only 24 patients with multi-ref ITP (68.57%) achieved initial transient response to steroid therapy (CR: n=10, R: n=12), compared to 91.61% responders in controls (p<.0001). In multivariate analysis, 4 factors were found to be associated with multi-ref ITP occurrence: (1) secondary ITP (OR: 4.81, 95%CI [1.31-17.86], p=.018), (2) presence of monoclonal gammopathy (OR: 5.93, 95%CI [1.08-32.48], p<.04), (3) bleeding symptoms at diagnosis (OR: 3.54 95%CI [1.11-11.22], p=.032) and (4) no response to steroid therapy (OR: 0.38 95%CI [0.20-0.72], p= .003). After a median follow-up of 84 months (range: 12-455), patients with multi-ref ITP have received a median of 10.5 lines of treatments (range: 6-15) including splenectomy, TPO-RAs and RTX, 5 patients (14%) died (intracranial hemorrhage, n=2; sepsis, n=1; breast cancer, n=1; unknown, n=1). Throughout the course of ITP, all patients required hospitalization; 22 (60%) received platelet transfusion, and 6 red-blood cells transfusion, 9 (24%) were admitted to intensive care units, 15 (40%) presented at least one bacterial infection, and 9 experienced at least one thrombosis (arterial, n=3; venous, n=6). At the end of follow-up, 20 patients (54%) were still non responders. Nine patients achieved a complete response: one after autologous hematopoietic stem cell transplantation, 2 after chemotherapy for hematological malignancy, and 5 after a combination of immunosuppressive therapy and TPO-RA.Conclusion: Our study demonstrated that multirefractory ITP is an extremely serious condition, associated with a high morbidity and mortality. Factors significantly associated with this phenotype were secondary ITP, association with autoimmune disorders, monoclonal gammopathy and no response to steroids. Most of these patients remained non-responsive to alternative lines of rescue treatment, but some successes has been obtained with the combination of immunosuppressive therapy and TPO-RA.(1) McMillan R, Durette C. Long-term outcomes in adults with chronic ITP after splenectomy failure. Blood 2004;104(4):956-60 DisclosuresSalles:Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche and Gilead Sciences: Research Funding; Celgene Corporation; Roche: Speakers Bureau. Cheze:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Michel:GSK: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; AMGEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Godeau:Roche: Research Funding; Amgen: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Integrative Analysis of Diffuse Large B Cell Lymphoma Mutational Landscape: A Lysa Study

IntroductionDiffuse Large B Cell Lymphoma (DLBCL) is the most common lymphoid malignancy, accounting for 30-40% of all Non Hodgkin Lymphomas. Gene expression profiling (GEP) has identified three main subtypes of DLBCL: Germinal Center B-cell like (GCB), Activated B-Cell like (ABC) and Primary Mediastinal B-cell Lymphoma (PMBL). Recently, Next Generation Sequencing (NGS) has enabled a more detailed characterization of DLBCL mutational profiles. Conventional techniques such as immunohistochemistry (IHC) and FISH are also widely used to describe DLBCL. However, no study has yet performed an integrative analysis of the mutational, gene expression, IHC and FISH profiles of DLBCL, in order to provide a comprehensive view of this disease.Methods215 patients with de novo DLBCL in the prospective, multicenter and randomized LNH-03B clinical trials led by the LYmphoma Study Association (LYSA) were included in this study. Microarray-based GEP identified 81 ABC, 83 GCB, 18 PMBL and 33 other. Mutational profiles of patients' tumor DNA were established using Lymphopanel NGS, designed to identify mutations in 34 genes important for lymphomagenesis. For each recurrently mutated gene, we applied ROMER (Ritchie, Nucleic Acids Res, 2015) to perform gene set enrichment analysis on differential expression profiles of mutant and wild-type patients, using a multifactorial model accounting for subtype. The gene sets were obtained from the MSIGDB Hallmarks (Subramanian A, PNAS, 2005) and Signaturedb (Schaffer, Immunol Rev, 2006) collections. When possible, IHC was performed for IgM (n=150), MYC (n=140), BCL2 (n=148), BCL6 (n=146), CD10 (n=152), FOXP1 (n=147) and MUM1 (n=152); FISH was performed for MYC (n=131), BCL2 (n=133) and BCL6 (n=131).ResultsAs expected, EZH2 mutations were significantly associated with upregulation of GCB gene expression (p<10-3), as well as downregulation of bivalent genes (p<10-2), H3K27me3 targets (p<10-2) and GSK343 upregulated genes (p=0.02) (Beguelin et al, Cancer Cell, 2013). IHC and FISH data further cemented EZH2 mutations' link to GCB subtype, and particularly the t(14;18)-positive subset (CD10+: OR=3.9 and p=0.01, MUM1-: OR=0.12 and p<10-3, BCL2+: OR=8.1 and p=0.04, BCL2 rearranged: OR=6.1 and p=0.04). BCL2 and CREBBP mutations were also linked to GCB subtype (CD10+ and MUM1-), and BCL2 mutations correlated with double-hit GCB DLBCL (Myc+: OR=6.6 and p<10-2, MYC rearranged: OR=7.6 and p=0.03, BCL2 rearranged: OR=20 and p<10-3).An association between BCL6 translocations and ABC subtype was confirmed, via a correlation with ABC-enriched CD79B mutations (p=0.02), although interestingly not with MYD88 mutations. MYD88 mutations were correlated with an upregulation of genes involved in proliferation or repressed by PRDM1 (FDR=0.04 each), as well as with an upregulation of genes involved in checkpoint controls, such as E2F targets and genes involved in DNA repair (FDR=0.03 each). All MYD88 mutants expressed FOXP1 in IHC (p<10-3) and MYD88 mutations were also correlated with IgM IHC positivity (OR=3.3 and p<10-2). TNFAIP3 mutations, also involved in constitutive NFkB activation, were associated with an upregulation of genes regulated by NFkB in response to TNF (FDR=0.02), as well as with an upregulation of KRAS-activated genes (FDR<10-2).PMBL-enriched mutations in our cohort were frequently associated with IgM and FoxP1 negative IHC, as expected (WHO 2008 and Roschewski, Nat Rev Clin Onc). XPO1 and ITPKB mutations were correlated with JAK-STAT pathway activation in the total cohort, including upregulation of interferon-inducible genes for both gene mutations (FDR=0.02 and FDR=0.08 respectively) and upregulation of BCL6-repressed genes for XPO1 mutations only (FDR=0.02). Interestingly, CD58 mutations were significantly correlated with upregulation of Nfkb pathway target genes (FDR=0.06), perhaps due to their negative impact on CD2 activation and ROS production inhibition.ConclusionThe results herein provide steps toward a comprehensive, multi-level overview of DLBCL. We highlight differential gene set expression linked to gene mutation status, as well as driver translocation-associated mutational profiles. By using an integrative analysis approach, this study broadens our understanding of DLBCL subtypes' diverse genetic backgrounds. DisclosuresBriere:St. Louis Hospital, Paris, France: Employment. Salles:Celgene Corporation; Roche: Speakers Bureau; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche and Gilead Sciences: Research Funding.

Baseline Metabolic Tumour Volume Predicts Outcome in High Tumor Burden Follicular Lymphoma. A Pooled Analysis of Three Multicenter Studies

Introduction The prognosis for patients with high tumor burden follicular lymphoma (FL) continues to improve in the modern immunochemotherapy era. However there is still a subgroup of 20% of patients who progress within 2 years of first line R-CHOP, (rituximab, doxorubicin, vincristine, prednisone) and experience a poor outcome (Casulo JCO 2015). To date, early identification of these high risk patients has been unsatisfactory.FDG-PET-CT (PET) is now the recommended imaging technique for staging and response assessment in FL and central scan review in a pooled analysis from three prospective studies has shown that post induction PET identifies a population with a high risk of death (Trotman, Lancet Haematol 2014). From this new pooled analysis we aimed to determine the prognostic impact of the total metabolic tumour volume (TMTV) measured on baseline PET and its added value to existing clinical prognostic indexes.Material and Methods 161 FL patients who had measurable quantitative data on baseline PET were selected from PET-FL, n=84 (Dupuis, JCO 2012), PRIMA, n=36 (Trotman, JCO 2011) and FOLL05 studies, n=41 (Luminari, Ann Oncol 2014). All met criteria for treatment of symptomatic high tumour burden or advanced stage disease. They received R-CHOP (80%), R-CVP (17%) or R-FM (4%) induction therapy with 24% receiving Rituximab maintenance. TMTV was computed on baseline PET by summing the metabolic volumes of all nodal and extranodal lesions using the established 41% SUVmax thresholding method (Meignan, Eur J Nucl Med Mol Imaging 2013). Optimal cut-points for binary outcomes were determined using X-tile® and ROC analysis. Prognostic value was assessed using univariate analysis and Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) and compared to other prognostic factors.Results 156 patients with available survival data were analyzed. Median age was 56 years; 92% were stage III/IV; 38% had FLIPI 3-5; and 29% had FLIPI2 3-5. Median SUVmax was 10 (Q1-Q3: 7-14). Median TMTV was 260 cm3 (Q1-Q3: 131-513 cm3). With a median follow-up of 64 months, 5-yr PFS and OS were 56% and 92% respectively in the whole population. Using a cut-off of 510 cm3, 39 patients (25%) had a high TMTV (>510cm3). Patients with high TMTV (>510cm3) had a significantly shorter PFS (Figure 1) and OS (Figure 2) than those with low TMTV (≤510cm3), (5-yrs PFS was 37% vs 62% p=.0007, HR=2.3 and 5-yr OS 83% vs 95% p=.0045, HR=4.1). Median PFS was not reached for patients with low TMTV vs. 34.8 months for patients with high TMTV. Beta2 microglobulin (Β2Μ) >ULN and FLIPI2 3-5 were also predicted factor of poor PFS, whereas FLIPI and LDH were not. When combined, FLIPI2 and TMTV had a significant impact on PFS and OS . The 5-yr PFS was 67%, 45% and 27% respectively for patients with: low TMTV and FLIPI2 0-2, high TMTV or FLIPI2 3-5, and high TMTV and FLIPI2 3-5. Incorporating TMTV >510cm3 into the FLIPI2 instead of the longest diameter of the largest lymph node >6cm improved results for PFS and OS. Patients with 3-5 factors with this revised index had a significantly worse outcome than patients with 0-2 factors (5yr PFS 38% vs 66%, p=0.001, HR=2.62, 5yr OS 84% vs 97%, HR=4.98, p=0.013).Conclusions In this pooled analysis from three prospective studies baselineTMTV is a strong predictor of outcome in high tumor burden FL. It adds value to existing pre-treatment prognostic indices in identifying a population for whom FL can no longer be characterized as indolent. The prognostic value of TMTV in stratifying patient outcomes needs to be validated in other populations treated with both R-CHOP +/- maintenance and R-Bendamustine. [Display omitted] [Display omitted] DisclosuresDupuis:ABBVIE: Membership on an entity's Board of Directors or advisory committees; ROCHE: Speakers Bureau. Haioun:Roche: Honoraria. Salles:Celgene Corporation; Roche and Gilead Sciences: Research Funding; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche: Speakers Bureau. Luminari:Roche: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Teva: Membership on an entity's Board of Directors or advisory committees.

Impact of 18 f-Fluoro-Deoxyglucose Positron Emission Tomography Imaging in the Management of Mantle Cell Lymphoma

Impact of 18 F-fluoro-deoxyglucose positron emission tomography (PET) imaging has become increasingly important in recent years in the management of patients with malignant lymphomas and is recommended for the staging and response to treatment assessment of both diffuse large B-cell and Hodgkin's lymphoma. Few data on the relevance of PET in the management of patients with mantle cell lymphoma (MCL) are available so far. Then, we retrospectively investigated the PET value for initial staging, interim response and predicting outcome in patients with MCL treated in two French institutions (Dijon University Hospital and the Centre Leon Berard, Lyon).From 2004 to 2013, a total of 61 de novo MCL patients assessed by PET were included. For each patient, were collected at baseline, the whole body SUVmax site, the presence of a bone marrow (BM) uptake, total metabolic tumour volume (TMTV) and total tumour glycolysis (TLG). The interim PET response after 3 or 4 cycles of induction treatment was assessed using the Deauville score and the quantitative variation of SUV between the baseline PET and the PET performed after 4 cycles of immunochemotherapy (ΔSUV).Patient's median age was 64 years [38 - 84]. At diagnosis, 92% presented a disseminated disease (stage III-IV). Mean MCL International Prognostic Index (MIPI) was 6.09 [5.89 - 6.29]. All patients received a first-line induction treatment. Twenty-eight (46%) received an autologous stem cell transplantation as consolidation treatment and 10 (16%) a rituximab maintenance. The baseline FDG uptake intensity was low (median SUVmax: 6.93 [2.5 - 25]) leading to consider that baseline PET was informative and suitable for a further PET reassessment in 40 (93%) patients. 72% of the patients with an informative baseline PET, had a SUVmax < 10 making the metabolic quantitative analyses (TMTV, TLG, ΔSUV) uninformative. Among the 46 (75%) patients with histologically proven BM involvement, only 14% of them had BM FDG uptake. After 3 to 4 cycles of induction treatment, 27 (75%) patients achieved a negative PET. With a median follow up of 27 months, a shorter PFS was related to a disseminated disease (stage III-IV) on the basis of baseline PET (2y-PFS: 47% vs 80% p = 0.03) and an insufficient interim metabolic response according to the Deauville score (score ≥ 4) (16% vs 64% p<0.01). However, in multivariate analysis, using the MIPI, the stage and the interim PET response as covariates, only a score of Deauville ≥ 4 (p = 0.0018, HR = 32.6 IC 95% [3.7 - 286.82]) and a MIPI>=6 (p = 0.04, HR = 7.1 IC 95% [1.1 - 46]) retained an independent negative impact on PFS.FDG avidity of LCM is usually low. PET underestimates BM involvement at diagnosis in 86 % of patients, compared with cytological and histological techniques, and has no independent prognostic value. The interim metabolic response assessed using the Deauville criteria is a prognosis factor independent from MIPI in patients with MCL. DisclosuresSalles:Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche and Gilead Sciences: Research Funding; Celgene Corporation; Roche: Speakers Bureau. Casasnovas:Gilead: Consultancy; Takeda: Consultancy; Roche: Consultancy, Research Funding.

Randomized Phase III Study Comparing an Early PET Driven Treatment De-Escalation to a Not PET-Monitored Strategy in Patients with Advanced Stages Hodgkin Lymphoma: Interim Analysis of the AHL2011 Lysa Study

BACKGROUNDEscalated BEACOPP (BEAesc) demonstrated a better disease control than ABVD but no overall survival (OS) improvement in patients with advanced Hodgkin Lymphoma (HL) (Federico et al , J Clin Oncol 2009, Viviani et al, N Engl J Med 2011, Mounier et al, Ann Oncol 2014). The superior efficiency of BEAesc is associated to a substantially higher immediate hematological toxicity, and an increased risk of secondary myelodysplasia/leukemia and infertility. So, to better manage HL treatment there is a need to identify early responding patients able to benefit from a strategy of dose intensity de-escalation after upfront BEAesc, without impairing the disease control. PET performed after 2 cycles of chemotherapy (PET2) might identify such a population suitable for receiving ABVD after 2 cycles of upfront BEAesc, and was implemented in the present study.METHODSThe AHL 2011 trial (NCT01358747) was designed to evaluate in 16 to 60 years old HL patients with Ann Arbor stage III, IV or high risk IIB, a treatment strategy driven by PET after 2 BEAesc cycles (PET2), delivering 4 cycles of ABVD for PET2 negative patients and 4 cycles of BEAesc for PET2 positive patients. This PET-driven strategy was randomly compared to a standard treatment not monitored by PET and delivering 6 cycles of BEAesc. A baseline PET was mandatory before treatment and PET2 were centrally reviewed and interpreted according to Deauville criteria within 48 hours. The allocation of treatment in the experimental arm was based on the PET2 central review results. PFS was the primary endpoint of the study with a hypothesis of non-inferiority of the PET driven arm compared to the standard arm with a margin of 10% (85% 5y-PFS in the standard arm vs >75% in the PET driven arm). An interim analysis of the primary endpoint was planned after 50% (n = 49) of the 97 scheduled events needed for the final analysis.RESULTSFrom May 2011 to May 2014, 823 patients were registered and 782 were eligible for the interim analysis including 401 patients in the arm A, and 381 in arm B. Patients characteristics were well balanced in both arms: median age was 30 years (16 - 60), 64% were male, 81% had nodular sclerosis and 12% mixed cellularity HL, 12% had stage IIB, 28% stage III, 60% stage IV, and 58% had an international prognosis score ≥3.After 2 cycles of BEAesc PET was positive in 97 (12%) patients and PET2 positivity was similar in the standard and experimental arms (n = 48, 12% and n = 49, 13% respectively). Based on PET2 results, 319 (84%) patients received 4 cycles of ABVD and 49 (13%) 4 additional cycles of BEAesc in the experimental arm.Grade ≥3 toxicity was significantly higher in patients receiving 6 cycles of BEAesc compared to those who received 2 cycles of BEAesc + 4 cycles of ABVD with more frequent anemia (11% vs 2%), leukopenia (85% vs 72%), thrombocytopenia (44% vs 13%), febrile neutropenia (6% vs 3%), and sepsis (7% vs 4%). 182 serious adverse events (SAE) related to treatment occurred in 108 (24%) patients treated with 6 cycles of BEAesc (leading to death in 4 cases), compared to 72 SAE (leading to death in 1 case) in 50 (15%) patients treated with 2 x BEAesc + 4 x ABVD (p<0.002). In these latter patients most of SAE (67%) occurred during the 2 first cycles of chemotherapy.With a median follow up of 16.3 months, in an intent to treat basis, the estimated 2y-PFS was similar in the standard (91.6%) and the PET driven arms (88.3%; p = 0.79). PET2 positivity was related to a significantly lower 2y-PFS compared to PET2 negative patients in the whole population (72.9% vs 92.8%; p<0.0001) and in both randomization arms (75.1% vs 94% and 70.8% vs 91.6% in the standard and PET driven arms, respectively; p<0.0001 for both). Overall survival was similar in both randomization arms and in PET2 positive or negative subsets of patients.CONCLUSIONSThis interim analysis suggests that PET performed after 2 cycles of BEAesc can be safely used to guide subsequent treatment and supports the response-adapted strategy delivering 4 cycles of ABVD for patients with negative PET2 (84%) without impairing the disease control. This approach allows to significantly reduce the treatment-related immediate toxicity in most patients and provides similar patients' outcome compared to standard BEAesc treatment. Still, PET positivity after 2 cycles of BEAesc is related to a higher risk of disease progression, encouraging to develop new treatment options in patients with PET2 positive advanced stage HL. DisclosuresCasasnovas:Roche: Consultancy, Research Funding; Takeda: Consultancy; Gilead: Consultancy. Salles:Celgene Corporation; Roche and Gilead Sciences: Research Funding; Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche: Speakers Bureau. Dupuis:ABBVIE: Membership on an entity's Board of Directors or advisory committees; ROCHE: Speakers Bureau. Morschhauser:Genentech Inc./Roche: Other: Advisory boards. Tempescul:Gilead: Other: Export Board Committee.

Updated Safety and Preliminary Efficacy Data from a Phase 1b Study Combining Venetoclax (GDC-0199, ABT-199) with Bendamustine/Rituximab in Patients with Relapsed/Refractory or Previously Untreated Chronic Lymphocytic Leukemia

Updated Safety and Preliminary Efficacy Data from a Phase 1b Study Combining Venetoclax (GDC-0199, ABT-199) with Bendamustine/Rituximab in Patients with Relapsed/Refractory or Previously Untreated Chronic Lymphocytic Leukemia

Activity of Idelalisib in High-Risk Follicular Lymphoma with Early Relapse Following Front Line Immunochemotherapy

Background: Follicular lymphoma (FL) is the most common indolent NHL with a heterogenous natural history of disease and a median survival of 8 to 12 y, albeit ranging between 1 to 20 y. Casulo et al. (2015) identified a high-risk FL cohort of patients with progression of disease (POD) at ≤24 months following initiation of immunochemotherapy with R-CHOP. Idelalisib (Zydelig) is a first-in-class, highly selective, oral inhibitor of PI3Kd which is indicated for relapsed FL or SLL following receipt of at least two lines of systemic chemotherapy. Retrospective subgroup analysis of the idelalisib registrational trial NCT01282424 (101-09) of a cohort with early POD following immunochemotherapy was performed to assess possible activity of idelalisib in this population.Methods: A subset of 46 patients enrolled in study 101-09 were identified as having been diagnosed with FL and having received first-line immunochemotherapy, of which 37 experienced early POD, defined as starting second-line treatment within 24 months of initial first-line treatment. For the latter group, descriptive statistics of demographic and baseline characteristics and inter-treatment intervals in months as well as Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) following initiation of immunochemotherapy and idelalisib were calculated.Population: Demographic characteristics of these 37 patients included median (range) age at initiation of idelalisib of 64 (33-84) y and 18 (48.6%) females. Histologic grade at diagnosis included 33 (89.2%) with grades 1 or 2 as well as 4 (10.8%) with grade 3A, while 21 (56.8%) patients had a FLIPI score ≥3. The mean (s.d.) number of prior therapies was 3.4±1.4, with a range of 2 to 8, while first-line therapies included 21 (56.8%) patients who received R-CHOP-based regimens, 7 (18.9%) who received BR, and 5 (13.5%) who received R-CVP. Mean (s.d.) inter-treatment intervals included 12.5±6.1 months between first- and second-line for all patients, 9.7±9.3 months between second- and third-line for all patients, 11.9±12.0 months between third- and fourth-line for 24 (64.9%) patients, and 11.8±7.6 months between fourth- and fifth-line for 15 (40.5%) patients. Median (range) time from first-line therapy to idelalisib initiation was 30.3 (8.9-94.7) months; no patient received idelalisib as second-line therapy.Results: Best responses included 5 (13.5%) patients with CR, 16 (43.2%) with PR, 2 (5.4%) with SD, and 1 (2.7%) with PD; median duration of response for those with CR or PR was 11.8 months (95% CI: 3.8 months, not evaluable). There were 7 (18.9%) deaths and 21 (56.8%) PFS events in this group. Estimated probabilities of survival (s.e.) and progression-free status at 2 y following initiation of idelalisib were 79%±7% and 29%±10%, respectively. Median PFS was 11.1 months (95% CI: 5.5, 19.3 months). Estimated probability of survival (s.e.) at 5 years following initiation of first-line treatment was 79%±8%. Median overall survival from both initiation of first-line immunochemotherapy as well as with idelalisib was not reached during the course of this study.Conclusions: Idelalisib may have significant clinical activity in high-risk and doubly-refractive FL following early relapse status post first-line immunochemotherapy. Given the small size of the studied subset population which may not be representative, further characterization in additional patients is warranted to ensure the generalizability of this finding, including consideration of further investigational protocols featuring targeted therapies employed both as single agents and in combination. [Display omitted] [Display omitted] [Display omitted] DisclosuresGopal:Gilead, Spectrum, Pfizer, Janssen, Seattle Genetics: Consultancy; Spectrum, Pfizer, BioMarin, Cephalon/Teva, Emergent/Abbott. Gilead, Janssen., Merck, Milennium, Piramal, Seattle Genetics, Giogen Idec, BMS: Research Funding; Millennium, Seattle Genetics, Sanofi-Aventis: Honoraria. Kahl:Roche/Genentech: Consultancy; Seattle Genetics: Consultancy; Millennium: Consultancy; Cell Therapeutics: Consultancy; Celgene: Consultancy; Infinity: Consultancy; Pharmacyclics: Consultancy; Juno: Consultancy. Flowers:Infinity Pharmaceuticals: Research Funding; Genentech: Research Funding; Spectrum: Research Funding; Millennium/Takeda: Research Funding; Seattle Genetics: Consultancy; Spectrum: Research Funding; Pharmacyclics: Research Funding; AbbVie: Research Funding; AbbVie: Research Funding; Gilead Sciences: Research Funding; Pharmacyclics: Research Funding; Onyx Pharmaceuticals: Research Funding; Celegene: Other: Unpaid consultant, Research Funding; OptumRx: Consultancy; Gilead Sciences: Research Funding; Janssen: Research Funding; Acerta: Research Funding; Millennium/Takeda: Research Funding; Acerta: Research Funding; Infinity Pharmaceuticals: Research Funding; Janssen: Research Funding; Onyx Pharmaceuticals: Research Funding. Martin:Janssen: Consultancy, Honoraria; Acerta: Consultancy; Gilead: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Bayer: Consultancy. Link:Genentech: Consultancy, Research Funding; Kite Pharma: Research Funding. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding. Ye:Gilead: Employment. Koh:Gilead: Employment. Abella:Gilead: Employment. Barr:Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Abbvie: Consultancy; Gilead: Consultancy. Salles:Calistoga Pharmaceuticals, Inc.; Celgene Corporation; Genentech, Inc.; Janssen Pharmaceutica Products, L.P.; Roche: Consultancy; Celgene Corporation; Roche and Gilead Sciences: Research Funding; Celgene Corporation; Roche: Speakers Bureau.

Response to Rituximab Induction Is a Predictive Biomarker in Post-Transplant Lymphoproliferative Disorder (PTLD) and Allows Successful Treatment Stratification in an International Phase II Trial Including 152 Patients

Response to Rituximab Induction Is a Predictive Biomarker in Post-Transplant Lymphoproliferative Disorder (PTLD) and Allows Successful Treatment Stratification in an International Phase II Trial Including 152 Patients

Gilead Continues its Diversification Strategy with Acquisition of Calistoga Pharmaceuticals

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CAL-101, An Isoform-Selective Inhibitor of Phosphatidylinositol 3-Kinase P110δ, Demonstrates Clinical Activity and Pharmacodynamic Effects In Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia

AbstractAbstract 55 Introduction:The class I phosphatidylinositol 3-kinases (PI3Ks) regulate cellular functions relevant to oncogenesis. Expression of the PI3K p110δ isoform (PI3Kδ) is restricted to cells of hematopoietic origin where it plays a key role in B cell proliferation and survival. In chronic lymphocytic leukemia (CLL) the PI3K pathway is constitutively activated and dependent on PI3Kδ. CAL-101 is an isoform-selective inhibitor of PI3Kδ (EC50 of 62 nM in a whole-blood assay with >200-fold selectivity relative to other PI3K isoforms) that inhibits PI3K signaling and induces apoptosis of CLL cells in vitro. Methods and Patients:This Phase 1 study evaluated the safety, pharmacokinetics, pharmacodynamics and clinical activity of CAL-101 in patients with relapsed or refractory hematologic malignancies. Sequential cohorts of patients were enrolled at progressively higher dose levels with cohort expansion based on toxicity profile and plasma exposure. CAL-101 was administered orally one or 2 times per day (QD or BID) continuously for 28-day cycles for up to 12 cycles (with the potential for more prolonged therapy on an extension protocol thereafter). Clinical response was evaluated according to standard criteria. Results:At data cutoff, the study had enrolled 37 patients with CLL. Patients included: males/females n=31 (84%)/6 (16%) with median age of 65 [range 37–82] years, refractory/relapsed disease n=24 (65%)/13 (35%), bulky disease n= 29 (81%), and adverse cytogenetics of del(17p), del(11q) or both n=22 (63%). The median number of prior therapies was 5 [range 2–14]. The number (%) of patients with specific prior therapies included: rituximab n=37 (100%), purine analog n=37 (100%), alkylating agent n= 31 (84%), and alemtuzumab n=12 (32%). CAL-101 dose levels were 50 mg BID (n=1), 100 mg BID (n=4), 150 mg BID (n=11), 200 mg BID (n=10), 350 mg BID (n=7) and 300 mg QD (n=4). The median number of treatment cycles was 9 [range 1–13], with 21 (57%) patients continuing on treatment (11 on study and 10 on the extension protocol after 12 cycles). Symptomatic adverse events were infrequent, usually low-grade, and not clearly CAL-101-related. Grade ≥3 pneumonias occurred in 9 (24%) patients. Grade ≥3 hematological laboratory abnormalities included neutropenia n=9 (24%), thrombocytopenia n=4 (11%) and anemia n=3 (8%) that were not usually considered CAL-101-related. A pharmacokinetic analysis of dose-proportionality showed minimal increases in plasma Cmax and AUC at CAL-101 doses >150 mg BID; these data, taken together with the tumor regression results, have proved helpful in supporting Phase 2–3 dose selection. Flow cytometry of CLL cells from patients showed that CAL-101 reduced constitutive expression of phospho-AKT to background levels when measured after 1 week of treatment (p<0.0001), demonstrating pharmacodynamic inhibition of activated PI3K signaling. Plasma concentrations of chemokines CCL3, CCL4, and CXCL13 were elevated at baseline and decreased significantly within 1 cycle of CAL-101 administration (p<0.001 for all comparisons). CAL-101 reduced lymphadenopathy in all 32 (100%) patients with at least 1 post-treatment tumor assessment; 29/32 (91%) achieved a lymph node response (≥50% reduction in target nodal lesions). An initial increase in peripheral absolute lymphocyte counts of >50% from baseline was observed in 21/35 (60%) patients; increases were maximal during the first 2 cycles and decreased thereafter; the pattern suggested drug-mediated lymphocyte redistribution. Considering nodal and peripheral blood changes together, partial responses were observed in 11/33 (33%) of patients. The median duration of response had not been reached; 7 patients had response durations of ≥6 months. Of 20 patients with CLL-related thrombocytopenia (baseline platelet counts <100,000/μ L), 15 (75%) had either an improvement to >100,000/μ L or a >50% increase from baseline. Conclusions:CAL-101, an oral PI3Kδ isoform-selective inhibitor, shows acceptable toxicity, positive pharmacodynamic effects, and favorable clinical activity in heavily pretreated patients with CLL, including patients with refractory disease, bulky lymphadenopathy, and poor-prognosis cytogenetics. The high level of lymph node regression and prolonged duration of symptomatic tumor control strongly support evaluation of CAL-101 alone and in combination with other chemo/immunotherapy approaches to CLL management. Disclosures:Byrd:Calistoga Pharmaceuticals: Consultancy, Equity Ownership. Brown:Calistoga: Consultancy. Kahl:Calistoga Pharmaceuticals: Consultancy, Research Funding. Lannutti:Calistoga Pharmaceutical Inc.: Employment. Giese:Calistoga Pharmaceuticals: Equity Ownership. Webb:Calistoga Pharmaceuticals: Employment. Ulrich:Calistoga Pharmaceuticals: Employment, Equity Ownership. Peterman:Calistoga Pharmaceuticals: Employment. Holes:Calistoga Pharmaceuticals: Employment. Yu:Calistoga Pharmaceuticals: Employment, Equity Ownership.

Clinical Pharmacokinetics of CAL-101, a p110δ Isoform-Selective PI3K Inhibitor, Following Single- and Multiple-Dose Administration In Healthy Volunteers and Patients with Hematological Malignancies

AbstractAbstract 1774Phosphatidylinositol 3-kinases (PI3Ks) regulate several cellular functions including motility, proliferation, and survival. PI3K pathway signaling is mediated by the Class I PI3K isoforms, α, β, δ and γ. The PI3K p110δ isoform is preferentially expressed in cells of hematological origin and in a variety of malignant cells. CAL-101 is a potent p110δ inhibitor with an EC50 of 62 nM in a whole-blood p110δ assay and >200-fold selectivity for p110δ relative to other PI3K isoforms. Consistent with this target selectivity, nonclinical toxicology and safety pharmacology data supported initial clinical assessment of oral CAL-101 in single-dose, multiple-dose, and food-effect studies in healthy volunteers. Because CAL-101 is a CYP450 3A4 substrate, the effect of ketoconazole (a potent CYP450 3A4 inhibitor) on CAL-101 pharmacokinetics was also evaluated in healthy volunteers. Preliminary evaluation of disposition, metabolism and elimination in healthy volunteers was achieved by coadministering a trace amount of [14C]CAL-101 and unlabeled CAL-101 either orally or intravenously (IV) with samples evaluated by accelerator mass spectrometry. CAL-101 pharmacokinetics (PK) were subsequently evaluated in patients with lymphoid malignancies. In healthy volunteers, CAL-101 was well tolerated at 400 mg (the highest single dose tested) and at 200 mg BID through 7 days (the highest multiple dose tested). The drug has also been symptomatically well tolerated in patients with lymphoid malignancies receiving CAL-101 at dose levels through 350 mg/kg (the highest dose tested) over many months. Monitorable, reversible transaminase elevations have been observed in some patients, most commonly in patients with lymphoma. No maximum tolerated dose (MTD) has been apparent. Increases in Cmax and AUC are less than dose proportional, revealing minimal gains in plasma exposure at dose levels >150 mg BID. The mean volume of distribution was moderate at 57.7 L. The t1/2 was ∼8 hours across all dose levels and there was no plasma accumulation over 7 or 28 days. The collective data support BID dosing at ≥150 mg; dose levels in this range maintain steady-state trough plasma concentrations that are >10-fold above the EC50 for the in vitro whole-blood assay. [14C]CAL-101 was metabolized to only 1 metabolite in plasma and CAL-101-derived materials were primarily excreted in feces (>65% of total dose) with minimal elimination via urine (<15% of total dose). A high-fat, high-calorie meal had no effect on Cmax but slowed absorption, leading to a shift in observed median Tmax from 1.5 h to 4.5 h, and a moderate 1.4-fold increase in AUC; these data suggest that CAL-101 can be given with or without food. When administered following 4 days of ketoconazole, increases in mean CAL-101 Cmax and AUC values were 1.3- and 1.8-fold, respectively; thus, CAL-101 is not a sensitive substrate for CYP450 3A4 and coadministration of CAL-101 with CYP450 3A4 inhibitors does not appear to be contraindicated. Taken together with clinical data documenting PI3K pathway inhibition, modulation of chemokine signaling, and substantial dose-dependent antitumor activity, these findings provide a characterization of CAL-101 clinical pharmacology that supports CAL-101 development as an investigational therapy for cancer and other indications. Disclosures:Webb:Calistoga Pharmaceuticals: Employment. Chen:Calistoga Pharmaceuticals: Employment. Yu:Calistoga Pharmaceuticals: Employment. Peterman:Calistoga Pharmaceuticals: Employment. Holes:Calistoga Pharmaceuticals: Employment. Lannutti:Calistoga Pharmaceutical Inc.: Employment. Miller:Calistoga Pharmaceuticals: Employment. Ulrich:Calistoga Pharmaceuticals: Employment, Equity Ownership.

Clinical Safety and Activity In a Phase 1 Study of CAL-101, An Isoform-Selective Inhibitor of Phosphatidylinositol 3-Kinase P110δ, In Patients with Relapsed or Refractory Non-Hodgkin Lymphoma

AbstractAbstract 1777 Introduction:The class I phosphatidylinositol 3-kinases (PI3Ks) regulate cellular functions relevant to oncogenesis. Expression of the PI3K p110δ isoform (PI3Kδ) is restricted to cells of hematopoietic origin where it plays a key role in B-cell proliferation and survival. In non-Hodgkin lymphoma (NHL) cells, constitutive PI3Kδ-dependent PI3K pathway activation is frequently observed. CAL-101 is an isoform-selective inhibitor of PI3Kδ that inhibits PI3K signaling and induces apoptosis of NHL cell lines in vitro. Methods and Patients:This Phase 1 study evaluated the safety, pharmacokinetics and activity of orally administered CAL-101 in patients with relapsed or refractory hematologic malignancies. Sequential cohorts of patients were enrolled at progressively higher dose levels with cohort expansion based on toxicity profile and plasma exposure. CAL-101 was administered orally once or 2 times per day (QD or BID) continuously in 28-day cycles for up to 12 cycles (with the potential for more prolonged therapy on an extension protocol thereafter). Tumor response was evaluated based on standard criteria but without a requirement for PET imaging. Results:At data cutoff, the study had enrolled 55 patients with NHL; 28 patients had indolent NHL (follicular lymphoma n=15, small lymphocytic lymphoma n=6, Waldenstrom's macroglobulinemia n=4, marginal zone lymphoma n=3) and 27 had aggressive NHL (mantle cell lymphoma [MCL] n=18, diffuse large B-cell lymphoma [DLBCL] n=9). Patient characteristics included 69% males (38 vs 17 females), median age [range] of 68 [32-82] years, 44% with refractory disease and 56% with relapsed disease. The median [range] number of prior therapies was 5 [1-12]. The proportion of patients with specific prior therapies included: indolent NHL-rituximab 96%, alkylator 86%, anthracycline 50%, purine analog 36%; aggressive NHL-rituximab 100%, alkylator 100%, anthracycline/anthracenedione 96%, plus bortezomib 72% in MCL patients. CAL-101 dose levels were 50 mg BID (n=2), 100 mg BID (n=11), 150 mg BID (n=8), 200 mg BID (n=16), 350 mg BID (n=9) and 300 mg QD (n=9). The median [range] number of treatment cycles was 4 [1-16], with 16 (29%) patients continuing on treatment (11 on study and 5 on the extension protocol after 12 cycles). Symptomatic adverse events were infrequent, usually low-grade, and not clearly CAL-101-related. Grade ≥3 hematological laboratory abnormalities included neutropenia n= 5 (9%), lymphopenia n=3 (5%), and thrombocytopenia n=3 (5%) with uncertain relationship to CAL-101. Grade≥3 ALT/AST elevations occurred in 18 (33%) patients with onset 2–8 weeks after CAL-101 initiation and resolution 2–4 weeks after CAL-101 interruption; after resolution of ALT/AST changes, most patients were rechallenged at the same or a reduced dose of CAL-101 and the majority of these patients were able to resume treatment without recurrence of transaminase elevations. Partial responses were observed at all dose levels, with respective overall n/N (response rates) in evaluable patients of 15/24 (62%) for indolent NHL, 10/16 (62%) for MCL and 0/9 (0%) for DLBCL. Respective response rates by relapsed or refractory status were 9/13 (69%) and 6/11 (55%) for indolent NHL and 8/11 (73%) and 2/5 (40%) for MCL. The median duration of response had not been reached in indolent NHL patients; 5 patients have had response durations of ≥6 months with response durations ranging to >16 months. The median [range] duration of response was 3 months [1 month to 8 months] in MCL. Pharmacodynamic data have supported drug activity; plasma concentrations of chemokines CCL22 and CCL17 were elevated at baseline and showed significant decreases within 1 cycle of CAL-101 treatment (p<0.001 for both comparisons). An evaluation of pharmacokinetics indicated minimal increases in plasma Cmax and AUC at CAL 101 doses >150 mg BID; these data, taken together with the tumor regression results, have proved helpful in supporting Phase 2–3 dose selection. Conclusions:CAL-101, an oral PI3Kδ isoform-selective inhibitor, shows acceptable safety and promising pharmacodynamic and clinical activity in patients with indolent NHL and MCL. The high rate of tumor regressions and protracted durations of tumor control in heavily pretreated patients support advancing CAL-101 into additional studies, both as a single agent and in combination with chemo/immunotherapy. Disclosures:Kahl:calistoga: Consultancy, Research Funding. Off Label Use: CAL-101 for relapsed lymphoma. Byrd:Calistoga Pharmaceutical Inc.: Equity Ownership. Flinn:calistoga: Research Funding. Wagner-Johnston:calistoga: Research Funding. Spurgeon:calistoga: Research Funding. Furman:GlaxoSmithKline: Clinical research funding, Consultancy, Research Funding, Speakers Bureau; Genentech: Clinical Research Funding, Consultancy, Research Funding, Speakers Bureau; Cephalon: Speakers Bureau, Speakers bureau; Calistoga: Consultancy, Honoraria; Celgene: Clinical Research, Consultancy, Research Funding. Brown:Genzyme: Research Funding; Celgene: Consultancy, Research Funding; Calistoga: Consultancy; Genentech: Consultancy. Coutre:calistoga: Research Funding. Lannutti:Calistoga Pharmaceutical Inc.: Employment. Ulrich:Calistoga Pharmaceuticals: Employment, Equity Ownership. Webb:Calistoga Pharmaceuticals: Employment. Peterman:Calistoga Pharmaceuticals: Employment. Holes:Calistoga Pharmaceuticals: Employment.

CAL-101, a Potent Selective Inhibitor of the p110δ Isoform of Phosphatidylinositol 3-kinase, Attenuates Pathway Signaling, Induces Apoptosis, and Overcomes Signals From the Microenvironment In Cellular Models of Hodgkin Lymphoma

AbstractAbstract 3926Phosphatidylinositide 3-kinases (PI3Ks) are a family of lipid kinases that are involved in signaling events which control a diverse number of cellular processes. The class I kinases contain 4 isoforms designated p110α, β, δ, γ, and are activated by cell surface receptors. Aberrant regulation of the PI3K signaling pathway is frequently observed in human malignancies including those of hematological origin. CAL-101 is an oral p110δ-specific inhibitor which has shown preclinical and clinical activity in non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). This compound is a potent p110δ inhibitor (EC50 of 65 nM in a whole-blood assay) with >200-fold selectivity over the other class I PI3K isoforms and no activity against Class II and III PI3K family members or other PI3K-related proteins, including mTOR and DNA-PK. Prior in vitro NHL studies revealed that CAL-101 induces caspase-dependent apoptosis, and inhibits CD40L-, BAFF-, CXCL12- and CXCL13-derived survival signals in cellular models (Lannutti BJ, et al., Blood 2010).To investigate the potential role of p110δ in Hodgkin lymphoma (HL) we screened a number of HL cell lines for p110δ isoform expression and constitutive PI3K pathway activation. We report high levels of p110δ protein and activated Akt in 5 of 5 HL cell lines evaluated (L428, L540, L591, L1236, KM-H2). Inhibition of p110δ with CAL-101 treatment of cell lines resulted in a reduction of Akt phosphorylation and a decrease in cellular viability. Because previous studies have established the importance of signals from the microenvironment for the survival and proliferation of malignant cells as well as for their resistance to standard therapies, we investigated the effect of p110δ inhibition by CAL-101 in HL cell line-stroma cocultures. In this setting, CAL-101 overcame tumor cell growth induced by coculture of HL cells with bone marrow stromal cells. In addition, CAL-101 induced dose-dependent apoptosis of HL cells at 48 hours. Furthermore, stromal cell coculture resulted in increased CCL5, CCL17, and CCL22 levels; productions of these chemokines by HL cells cultured in the presence of stromal cells were reduced by CAL-101 in a dose-dependent manner. These results indicate that specific inhibition of p110δ may disrupt signals between HL cells and their microenvironment, thereby providing the preclinical rationale for clinical evaluation of CAL-101 as a novel therapeutic approach in patients with Hodgkin lymphoma. Disclosures:Meadows:Calistoga Pharmaceuticals: Employment. Kashishian:Calistoga Pharmaceuticals: Employment. Johnson:Calistoga Pharmaceuticals: Employment. Lannutti:Calistoga Pharmaceutical Inc.: Employment.

Lenalidomide-Dependent Activation of the Phosphatidylinositol 3-kinase-δ Pathway Is Antagonized by CAL-101 In Chronic Lymphocytic Leukemia

AbstractAbstract 1821Lenalidomide is an oral immune-modulating agent that has been shown to have clinical activity in patients with treatment-naive and previously treated chronic lymphocytic leukemia (CLL). In CLL, a disease-specific phenomenon of drug-induced tumor flare is often observed that results in lymph node enlargement, rash, and cytokine release. We and others have attributed both lenalidomide-induced tumor flare and cytokine release in part to CLL cell activation, with concomitant increase in surface co-stimulatory molecules including CD154. The potential consequences of such activation by lenalidomide in CLL are multiple. In symptomatic, previously untreated CLL, activation of tumor cells by lenalidomide likely contributes to reversal of hypogammaglobulinemia in a subset of patients. Additionally, activation of CLL cells increases their capacity for antigen presentation, potentially facilitating a clinically beneficial development of tumor-specific antibodies toward antigens such as ROR1. In patients with previously treated CLL, lenalidomide therapy does not reverse hypogammaglobulinemia. However, treatment has been documented to increase serum b-FGF and VEGF levels, which correlates with lack of response. Previous work demonstrates that CLL cells predominately utilize the PI3K p110δ isoform for activation following CD154 signaling. Given our prior findings of prominent lenalidomide induction of CD40-CD154 signaling in vitro and in vivo, we focused initially on molecular interrogation of isoforms responsible for this in CLL cells. Utilizing primary CLL cells, we demonstrated that inhibition of PI3K-δ signaling by CAL-101, a clinically relevant PI3K-δ isoform-specific inhibitor, abrogated lenalidomide-induced activation of CLL cells by directly reducing PI3K enzymatic activity and also reducing phosphorylation of the downstream PI3K target AKT. Parallel studies with siRNA targeted to the p110δ isoform of PI3K demonstrated antagonism of lenalidomide-induced AKT phosphorylation. Furthermore, we found that inhibition of PI3K-δ by CAL-101 at therapeutically relevant concentrations (1 μM) prevented up-regulation of CD40, CD154, and CD86 by lenalidomide and also antagonized production of IgM by normal B-cells co-cultured with CLL cells. Collectively, these data demonstrate the importance of PI3K-δ signaling in modulating the pharmacological effects of lenalidomide in CLL cell activation including up-regulation of CD40, CD154, CD86 and active CLL cell co-stimulation of normal B-cells. Our findings suggest that clinical evaluation of combination strategies of lenalidomide and CAL-101 in treatment-naive patients with CLL should be performed with careful pharmacodynamic monitoring of immune modulation and signaling to best preserve the clinical benefits of both drugs.This work is supported by the Leukemia and Lymphoma Society, D. Warren Brown Foundation, and The OSU Leukemia SPORE grant funded by the NCI. CAL-101 was provided by Calistoga Pharmaceuticals, Inc. Disclosures:Jones:Glaxo Smith-Kline: Consultancy; Abbott: Research Funding. Lannutti:Calistoga Pharmaceutical Inc.: Employment. Byrd:Calistoga Pharmaceutical Inc.: Equity Ownership. Johnson:Calistoga Pharmaceutical Inc.: Research Funding.

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

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