Lewis J. Cohen

Asparaginase antibody and asparaginase activity in children with higher-risk acute lymphoblastic leukemia: Children's Cancer Group Study CCG-1961.

We investigated the anti-asparaginase antibody (Ab) and asparaginase enzymatic activity in the sera of 1,001 patients (CCG-1961) with high-risk acute lymphoblastic leukemia (HR-ALL). Patients received nine doses of native Escherichia coli asparaginase during induction. Half of rapid early responders (RER) were randomly assigned to standard intensity arms and continued to receive native asparaginase. The other RER patients and all slow early responders received 6 or 10 doses of PEG-asparaginase. Serum samples (n = 3,193) were assayed for determination of asparaginase Ab titers and enzymatic activity. Three hundred ninety of 1,001 patients (39%) had no elevation of Ab among multiple evaluations—that is, were Abnegative (<1.1 over negative control)—and 611 patients (61%) had an elevated Ab titer (>1.1). Among these 611 patients, 447 had no measurable asparaginase activity during therapy. Patients who were Ab-positive but had no clinical allergies continued to receive E. coli asparaginase, the activity of which declined precipitately. No detectable asparaginase activity was found in 81 of 88 Ab-positive patients shortly after asparaginase injections (94% neutralizing Ab). The Ab-positive patients with clinical allergies subsequently were given Erwinase and achieved substantial activity (0.1–0.4 IU/ml). An interim analysis of 280 patients who were followed for 30 months from induction demonstrated that the Ab-positive titers during interim maintenance-1 and in delayed intensification-1 were associated with an increased rate of events. The CCG-1961 treatment schedule was very immunogenic, plausibly due to initially administrated native asparaginase. Anti-asparaginase Ab was associated with undetectable asparaginase activity and may be correlated with adverse outcomes in HR ALL.

BMS-936564/MDX-1338: A Fully Human Anti-CXCR4 Antibody Induces Apoptosis In Vitro and Shows Antitumor Activity In Vivo in Hematologic Malignancies

Purpose: CXCR4 has been identified as a prognostic marker for acute myeloid leukemia (AML) and other malignancies. We describe the development and characterization of a fully human antibody to CXCR4 and its application for therapy of AML, non–Hodgkin lymphoma (NHL), chronic lymphoid leukemia (CLL), and multiple myeloma. Experimental Design: Human transgenic mice were immunized with CXCR4-expressing cells, and antibodies reactive with CXCR4 were analyzed for apoptosis induction and ability to interfere with CXCL12-induced migration and calcium flux. In vivo efficacy was determined in multiple AML, NHL, and multiple myeloma xenograft tumors in severe combined immunodeficient mice. Results: BMS-936564/MDX-1338 is a fully human IgG4 monoclonal antibody that specifically recognizes human CXCR4. In vitro studies show that MDX-1338 binds to CXCR4-expressing cells with low nanomolar affinity, blocks CXCL12 binding to CXCR4-expressing cells, and inhibits CXCL12-induced migration and calcium flux with low nanomolar EC50 values. When given as monotherapy, MDX-1338 exhibits antitumor activity in established tumors including AML, NHL, and multiple myeloma xenograft models. In addition, we show that MDX-1338 induced apoptosis on a panel of cell lines and propose that antibody-induced apoptosis is one of the mechanisms of tumor growth inhibition. Conclusions: BMS-936564/MDX-1338 is a potent CXCR4 antagonist which is efficacious as monotherapy in tumor-bearing mice and is currently in phase I for the treatment of relapsed/refractory AML, NHL, CLL, and multiple myeloma. Clin Cancer Res; 19(2); 357–66. ©2012 AACR.

C1013G/CXCR4 acts as a driver mutation of tumor progression and modulator of drug resistance in lymphoplasmacytic lymphoma

The C-X-C chemokine receptor type 4 (CXCR4) plays a crucial role in modulating cell trafficking in hematopoietic stem cells and clonal B cells. We screened 418 patients with B-cell lymphoproliferative disorders and described the presence of the C1013G/CXCR4 warts, hypogammaglobulinemia, infections, and myelokathexis-associated mutation in 28.2% (37/131) of patients with lymphoplasmacytic lymphoma (Waldenström macroglobulinemia [WM]), being either absent or present in only 7% of other B-cell lymphomas. In vivo functional characterization demonstrates its activating role in WM cells, as demonstrated by significant tumor proliferation and dissemination to extramedullary organs, leading to disease progression and decreased survival. The use of a monoclonal antibody anti-CXCR4 led to significant tumor reduction in a C1013G/CXCR4 WM model, whereas drug resistance was observed in mutated WM cells exposed to Brutons tyrosine kinase, mammalian target of rapamycin, and phosphatidylinositol 3-kinase inhibitors, but not proteasome inhibitors. These findings demonstrate that C1013G/CXCR4 is an activating mutation in WM and support its role as a critical regulator of WM molecular pathogenesis and as an important therapeutic target.

Immunomodulatory Activity of Nivolumab in Metastatic Renal Cell Carcinoma

Purpose: Nivolumab, an anti-PD-1 immune checkpoint inhibitor, improved overall survival versus everolimus in a phase 3 trial of previously treated patients with metastatic renal cell carcinoma (mRCC). We investigated immunomodulatory activity of nivolumab in a hypothesis-generating prospective mRCC trial. Experimental Design: Nivolumab was administered intravenously every 3 weeks at 0.3, 2, or 10 mg/kg to previously treated patients and 10 mg/kg to treatment-naïve patients with mRCC. Baseline and on-treatment biopsies and blood were obtained. Clinical activity, tumor-associated lymphocytes, PD-L1 expression (Dako immunohistochemistry; ≥5% vs. <5% tumor membrane staining), tumor gene expression (Affymetrix U219), serum chemokines, and safety were assessed. Results: In 91 treated patients, median overall survival [95% confidence interval (CI)] was 16.4 months [10.1 to not reached (NR)] for nivolumab 0.3 mg/kg, NR for 2 mg/kg, 25.2 months (12.0 to NR) for 10 mg/kg, and NR for treatment-naïve patients. Median percent change from baseline in tumor-associated lymphocytes was 69% (CD3+), 180% (CD4+), and 117% (CD8+). Of 56 baseline biopsies, 32% had ≥5% PD-L1 expression, and there was no consistent change from baseline to on-treatment biopsies. Transcriptional changes in tumors on treatment included upregulation of IFNγ-stimulated genes (e.g., CXCL9). Median increases in chemokine levels from baseline to C2D8 were 101% (CXCL9) and 37% (CXCL10) in peripheral blood. No new safety signals were identified. Conclusions: Immunomodulatory effects of PD-1 inhibition were demonstrated through multiple lines of evidence across nivolumab doses. Biomarker changes from baseline reflect nivolumab pharmacodynamics in the tumor microenvironment. These data may inform potential combinations. Clin Cancer Res; 22(22); 5461–71. ©2016 AACR.

Ulocuplumab (BMS-936564 / MDX1338): a fully human anti-CXCR4 antibody induces cell death in chronic lymphocytic leukemia mediated through a reactive oxygen species-dependent pathway.

The CXCR4 receptor (Chemokine C-X-C motif receptor 4) is highly expressed in different hematological malignancies including chronic lymphocytic leukemia (CLL). The CXCR4 ligand (CXCL12) stimulates CXCR4 promoting cell survival and proliferation, and may contribute to the tropism of leukemia cells towards lymphoid tissues. Therefore, strategies targeting CXCR4 may constitute an effective therapeutic approach for CLL. To address that question, we studied the effect of Ulocuplumab (BMS-936564), a fully human IgG4 anti-CXCR4 antibody, using a stroma – CLL cells co-culture model. We found that Ulocuplumab (BMS-936564) inhibited CXCL12 mediated CXCR4 activation-migration of CLL cells at nanomolar concentrations. This effect was comparable to AMD3100 (Plerixafor - Mozobil), a small molecule CXCR4 inhibitor. However, Ulocuplumab (BMS-936564) but not AMD3100 induced apoptosis in CLL at nanomolar concentrations in the presence or absence of stromal cell support. This pro-apoptotic effect was independent of CLL high-risk prognostic markers, was associated with production of reactive oxygen species and did not require caspase activation. Overall, these findings are evidence that Ulocuplumab (BMS-936564) has biological activity in CLL, highlight the relevance of the CXCR4-CXCL12 pathway as a therapeutic target in CLL, and provide biological rationale for ongoing clinical trials in CLL and other hematological malignancies.

1051PDIMMUNOMODULATORY ACTIVITY OF NIVOLUMAB IN PREVIOUSLY TREATED AND UNTREATED METASTATIC RENAL CELL CARCINOMA (MRCC): BIOMARKER-BASED RESULTS FROM A RANDOMIZED CLINICAL TRIAL

ABSTRACT Aim: Nivolumab, a fully human IgG4 programmed death-1 (PD-1) immune checkpoint inhibitor antibody, has shown encouraging activity in mRCC. This trial assessed immunomodulatory activity, antitumor response, and safety of nivolumab in patients (pts) with mRCC. Methods: 91 pts received nivolumab IV Q3W: previously treated pts (1-3 prior therapies; ≥1 anti-angiogenic agent) received 0.3 (n = 22), 2 (n = 22), or 10 mg/kg (n = 23); untreated pts received 10 mg/kg (n = 24). Fresh biopsies and serum were obtained at baseline (BL) and at nivolumab cycle 2 day 8 (C2D8; biopsy) and cycle 4 day 1 (C4D1; serum). The primary objective assessed immunomodulatory activity of nivolumab on serum chemokines (CXCL9, CXCL10) and tumor T cell infiltrates from BL to posttreatment. Secondary/exploratory objectives included safety, antitumor activity (ORR, RECIST 1.1; PFS), BL and treatment-induced changes in PD-1 ligand (PD-L1) expression (Dako immunohistochemistry assay; PD-L1 positivity: >5% tumor membrane staining at any intensity) and association of clinical activity with BL PD-L1 expression. Results: T cell infiltrates increased by a median of 70% (CD3 + ; range 53-220%) and 88% (CD8 + ; 61-257%) from BL to C2D8. Mean increase from BL to C4D1 was 180% for CXCL9 and 79% for CXCL10. In evaluable pts ORR was 17% (15/90); 18% previously treated, 13% untreated pts. Median duration of response was 64 weeks; 6 (43%) responses are ongoing. PFS rate at 48 wks was 18% (16/90). Grade 3-4 AEs occurred in 15% (14/91): colitis and elevated AST (n = 2 each), diarrhea, elevated ALT and pneumonitis (n = 1 each). Of 56 evaluable pretreatment biopsies, 18 (32%) were PD-L1+. ORR was 22% (4/18) for PD-L1+ pts vs 8% (3/38) for PD-L1–. In 5/27 (19%) matched biopsy pairs PD-L1 expression increased >5% by C2D8. Conclusions: In this prospective study, changes in biomarkers were consistent with PD-1 inhibition, evidence of nivolumabs immunomodulatory effects in serum and the tumor microenvironment. Nivolumab demonstrated antitumor activity and manageable safety in pts with previously treated or untreated mRCC. Responses were numerically higher in PD-L1+ pts, but also present in PD-L1– pts. Disclosure: T. Choueiri: Ad Board: Pfizer, Novartis, GSK, Bayer, Aveo Research: Pfizer; M.N. Fishman: I have received funding for research trials from Bristol Myers Squibb; B. Escudier: I have received compensation for consultation/ advisory position to the following: Bayer, Pfizer, Novartis I have received honoraria from the following: Bayer, Roche, Pfizer, Genentech, Novartis, AVEO, GSK; W.M. Stadler: University of Chicago/I has received funding for research from Bristol Myers-Squibb; J.L. Perez-Garcia: I have received funding for research from Bristol Myers Squibb; M.R. Harrison: I have consulted/worked in advisory role to: Novartis, AVEO, Exelixis, Bayer; I have received honoraria from: Novartis, Prometheus; I have received funding for research from: BMS, Argos, Exelixis, Pfizer, Exelixis; E.R. Plimack: Has received grants and/or personal fees from: BMS, GSK, Dendreon, Astellas, Pfizer, Amgen, Acceleron, MedImmune, Merck, Lilly, AZ; L. Appleman: I have received funding from Bristol Myers-Squibb; L. Fong: I have received funding for research from Bristol Myers-Squibb; C.G. Drake: Sponsored Research: Aduro Biotech, BMS, Janssen, I have consulted to: BMS, Compugen, Dendreon, Pfizer, Roche/ Genentech, NexImmune; L. Cohen: I am an employee of Bristol Myers Squibb; S. Srivastava: I am an employee of Bristol Myers Squibb; M. Jure-Kunkel: I am an employee of and have stock or other ownership interest in BMS; Q. Hong: I am an employee of and have stock or other ownership interest in BMS; J. Kurland: I am an employee of and have stock or other ownership interest in BMS; M. Sznol: I have received personal Fees from BMS, Amgen, Medimmune, Genentech, Symphogen, Nektar, Anaeropharma, Immune Design, Merus, Lion Biotechnologies, Kyowa-Kirin, Astra-Zeneca-Medimmune. All other authors have declared no conflicts of interest.