Pharmacodynamic activity of BMS-986156, a glucocorticoid-induced TNF receptor-related protein agonist, alone or in combination with nivolumab in patients with advanced solid tumors

BACKGROUND

The success of immune checkpoint inhibitors has revolutionized cancer treatment options and triggered development of new complementary immunotherapeutic strategies, including T-cell co-stimulatory molecules, such as glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR). BMS-986156 is a fully agonistic human immunoglobulin G subclass 1 monoclonal antibody targeting GITR. We recently presented the clinical data for BMS-986156 with or without nivolumab, which demonstrated no compelling evidence of clinical activity in patients with advanced solid tumors. Here, we further report the pharmacodynamic (PD) biomarker data from this open-label, first-in-human, phase I/IIa study of BMS-986156 ± nivolumab in patients with advanced solid tumors (NCT02598960).

MATERIALS AND METHODS

We analyzed PD changes of circulating immune cell subsets and cytokines in peripheral blood or serum samples collected from a dataset of 292 patients with solid tumors before and during treatment with BMS-986156 ± nivolumab. PD changes in the tumor immune microenvironment were measured by immunohistochemistry and a targeted gene expression panel.

RESULTS

BMS-986156 + nivolumab induced a significant increase in peripheral T-cell and natural killer (NK) cell proliferation and activation, accompanied by production of proinflammatory cytokines. However, no significant changes in expression of CD8A, programmed death-ligand 1, tumor necrosis factor receptor superfamily members, or key genes linked with functional parameters of T and NK cells were observed in tumor tissue upon treatment with BMS-986156.

CONCLUSIONS

Despite the robust evidence of peripheral PD activity of BMS-986156, with or without nivolumab, limited evidence of T- or NK cell activation in the tumor microenvironment was observed. The data therefore explain, at least in part, the lack of clinical activity of BMS-986156 with or without nivolumab in unselected populations of cancer patients.

Abstract P2-08-01: PIK3CA mutations associate with decreased Ki67 in early stage breast cancer (BC) and better outcomes in patients even among those with low Ki67 tumors

Background: In studies of over 450 BC patients (pts) with > 10 years follow-up, pts with PIK3CA-mutated primary tumors had improved clinical outcome (Kalinsky et al 2009, Cizkova et al 2012). PIK3CA mutations associated with favorable clinicopathologic features: lower grade, smaller size, lymph node negativity (−), ER positivity (+), HER2−. In BC, several studies have suggested that PIK3CA mutations do not associate with PI3K/mTOR pathway activation (Loi et al 2010, Stemke-Hale et al 2008). To gain additional insight into the favorable biology imparted by a PIK3CA mutation in early stage BC and to identify predictive biomarkers, we performed immunohistochemistry (IHC) on tissue microarrays (TMA) constructed from 590 primary BCs.

Methods: TMAs derived from FFPE tumors previously genotyped for PIK3CA mutations (rate of 32.5%, 192/590) were stained for ER, HER2 and AR (Kalinsky et al 2009). Here, we performed additional stains for MIB1 (Ki67 proliferation index, Ki67), p53 and markers of PI3K pathway activation (pS6, PTEN). Slides were scanned with Aperio ScanScope XT and segmented using TMALab (Aperio). Images were analyzed with the Aperio algorithm based on staining pattern (nuclear, cytoplasmic, membrane) and scored for % + and intensity. Manual review was performed for tumors with less than 3 cores or discordant results. PTEN was scored manually: 0 (no tumor staining, PTEN loss), 1 (tumor < stroma), or 2 (tumor ≥ stroma). P values were based on the log-rank test for comparison of Kaplan-Meier curves for disease free survival (DFS), Chi-square test for categorical variables and t-test for continuous variables.

Results: On average, 66 cases (11%) were non-informative for each IHC stain, due to missing cores or insufficient tumor cells. In a binary analysis of Ki67 using a cutoff of ≥10% + cells, PIK3CA mutated tumors demonstrated significantly lower proliferation index with only 9.4% of tumors (16/170) having high Ki67 as compared to 23.6% of wild-type PIK3CA tumors (82/347) (P = .001). Ki67 was also highly associated with PIK3CA genotype when analyzed with a cutoff of ≥13.25% + cells or as a continuous variable. Importantly, DFS was significantly different when analyzed by PIK3CA genotype and Ki67 (P = .01). Among pts with low Ki67 tumors (n = 419), PIK3CA mutation associated with longer DFS (10yr 79%, CI 69–85) as compared to wild-type PIK3CA (10yr 71%, CI 64–77). When PI3K pathway interactions were analyzed, PTEN loss associated with wild-type PIK3CA (P<.001), although PTEN loss occurred with mutated PIK3CA in 11 hormone receptor (HR)+ tumors. In analysis of pS6 with a binary cutoff of ≥20% + cells, high pS6 associated with HER2+ (P<.001), HR- (P<.001) and high tumor grade (P = 0.003), but did not associate with PIK3CA genotype (P = .13). PIK3CA mutation was associated with lower pS6 when pS6 % + cells was analyzed as a continuous variable (P = .01).

Conclusions: PIK3CA mutation associates with lower Ki67 in early stage BC. Even among pts with low Ki67 tumors, PIK3CA mutation associates with improved clinical oucome. pS6 is not increased in PIK3CA-mutated tumors which likely indicates that mTORC1 signaling is not activated as a result of PIK3CA mutation in early stage ER+ BC.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-08-01.

Mutant PIK3CA Is Detected in Both Pre-Invasive and Recurrent Breast Cancer

BackgroundWe identified somatic PIK3CA mutations in 32.5% of 590 primary invasive breast cancers (BC) (manuscript in press: Clinical Cancer Research). Detected by massARRAY genotyping, PIK3CA mutations significantly associate with favorable clinicopathologic features and improved clinical outcome, including overall and breast cancer-specific survival. Given the strong association between PIK3CA mutations and hormone receptor (HR) positivity, one hypothesis is that PIK3CA mutations 'drive' HR positive BC and will be detected in pre-invasive breast tumors. As PIK3CA mutations offer a protective effect in BC, it has not been determined whether PIK3CA mutations are selected for in disease progression or whether additional collaborating mutations are required.MethodsTo determine the concordance of PIK3CA mutations and assess the acquisition of additional oncogene mutations, available matched tissue samples, from the previous database, were procured and underwent massARRAY genotyping (n = 83). Two mm cores were macro-dissected from matched formalin-fixed, paraffin embedded tissue, including normal breast tissue, benign lymph nodes (LN), ductal carcinoma-in-situ (DCIS), regional LN metastases (mets), and distant mets. MassARRAY (Sequenom) genotyping was performed on native DNA to identify rare and hotspot PIK3CA mutations, as well as AKT1 (E17K), RAS, and RET mutations.ResultsConcordance of PIK3CA mutations is noted between primary BC and DCIS, except for one rare PIK3CA mutation (Q546R) not detected in DCIS (4/5). No PIK3CA mutations are detected in normal breast tissue (0/8) or benign LN (0/6). Rare and hotspot PIK3CA mutations in primary BC are detected in 87.5% (7/8) matched regional LN met and 80 % (4/5) distant mets. For the patient with the disconcordant regional LN met, the rare PIK3CA mutation (H1047L) identified in primary BC is also present in the distant met site. Notably, for the single disconcordant PIK3CA met site, a rare PIK3CA mutation (E545A) is detected in a primary tumor, regional LN met, and bone met and is absent in a second bone met, in which a KRAS (G12C) mutation has been identified. One concomitant hotspot PIK3CA (E542K)/KRAS (G12C) mutation is present in both primary BC and paired DCIS. Complete concordance of AKT1 (E17K) mutations has been identified between in DCIS, primary BC, regional LN met, and distant mets (n=4).ConclusionsWe recently defined the positive prognostic significance of PIK3CA mutations in breast cancer. PIK3CA and AKT1 (E17K) mutations are early events in breast cancer, occurring in pre-invasive tumors. Despite the protective effect of PIK3CA mutations on clinical outcome, they persist and are selected for in disease progression, as they are detected in regional LN and distant mets. Complete concordance is identified between hotspot PIK3CA mutated primary BC and matched tumors samples, suggesting that PIK3CA mutations with higher oncogenic potency are maintained in tumor progression. These findings support that targeting the PI3K pathway may assist in tailoring therapy to appropriate patient populations. We are expanding matched tissue collection from a separate patient cohort to further assess genomic and functional genomic change with disease progression.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 5164.

Prognostic value of quantitative image analysis (QIA) for determination of proliferative index in mantle cell lymphoma (MCL) treated with sequential chemotherapy followed by high-dose therapy and autologous stem cell rescue (HDT/ASCR)

e19522

Background: Gene expression studies have demonstrated that the proliferation signature is the most important factor in determination of outcome in MCL. However, visual assessment of immunohistochemical staining is not standardized. QIA of MIB-1/Ki67 staining may have a greater reliability for determination of the PI. We tested the agreement between manual counting (MC) and QIA and its prognostic value in patients with MCL. Methods: 105 patients with MCL underwent therapy for de novo MCL, of these, 66 had slides stained with MIB-1 for the analysis. The PI was determined in three ways: 1) estimation by a hematopathologist using a microscope (manual count, MC); 2) visual estimation by an independent hematopathologist after whole slide digitization; and 3) QIA software (color deconvolution algorithm). The survival analysis was restricted to 47 patients that were treated with sequential therapy followed by upfront consolidation with HDT/ASCR. Results: A median of 612,394 cells per slide were analyzed by QIA. There was a good correlation between the QIA and both the MC under the microscope and digital image (0.9061, P<0.001 and 0.9336, P<0.001; Spearman test) as well as between the pathologists (0.897, P<0.001). Based on a 30% cutoff, the agreements (kappa test) were: interobserver, 0.6 (80% of slides); between QIA and MC of visual image, 0.86 (94% of slides); and between the QIA and MC using standard microscopy, 0.72 (86% of slides). In the survival analysis, the median PI was 25% (0.7% to 74%). By QIA, 27 patients had a low PI (<30%) and 20 patients had a high PI. At a median follow-up of 4.4 years, the 5 year overall survival (OS) and event free survival (EFS) were inferior in the high PI cohort (66% v 93%, P=0.003 and 0 v 71%, P<0.001, respectively). In a Cox regression analysis, both OS and EFS were significantly associated with PI and not associated with either MIPI or inclusion of rituximab during therapy. No event was reported after 4.7 years of follow-up in the low-PI group. Conclusions: Digital image analysis of MIB-1/Ki67 staining is highly reproducible and further validates the prognostic significance of a high PI in MCL using a threshold of 30%.

No significant financial relationships to disclose.

Use of multiplex mutation genotyping to identify novel and protective mutations in breast cancer

11004

Background: We recently analyzed 590 primary invasive breast tumors for PIK3CA mutations by multiplex massARRAY genotyping. We identified a 32.5% PIK3CA mutation rate (manuscript submitted). Associations between PIK3CA mutation status and favorable pathology, such as lower grade tumors, lymph node negativity and hormone receptor (HR) positivity, were observed. Multiplex analysis allows the rapid assessment of mutations not commonly described in breast cancer. To identify activated pathways that may serve as predictive biomarkers, tissue microarrays (TMA) underwent immunohistochemical (IHC) analysis. Methods: 590 archival formalin-fixed paraffin embedded (FFPE) tumors > 1 cm were used to ensure adequate tissue procurement for mutation detection and TMA construction. MassARRAY (Sequenom) genotyping was performed on native DNA to identify PIK3CA, RAS, RET, and other known mutations. IHC staining of the TMAs included assessment of steroid nuclear receptors, HER2 expression, Akt pathway activation (including pAKT, p70S6K, eIF4E), and PTEN. Stained TMAs underwent digital quantitative image analysis and scoring (Aperio, Vista, CA). The Kaplan-Meier method and Cox models were used in univariate and multivariate analysis for associations of mutation status and clinicopathologic features on overall survival (OS) and breast cancer-specific survival (BCSS). Results: Compared to wild-type, PIK3CA mutated tumors (median f/u: 12.8 years) demonstrate a significant improvement in OS (p=0.03) and BCSS (p=0.004). For patients with any PIK3CA mutation, the improvement in BCSS is maintained in HR positive and ER negative subgroups. In addition to PIK3CA mutations, RAS and RET mutations are identified in a small proportion of breast tumors. Additional analysis to evaluate the association of mutation status and biomarker data derived from the TMA analysis will be performed for meeting presentation. Conclusions: We have recently defined the positive prognostic significance of PIK3CA mutations in breast cancer. RAS mutations are confirmed to occur rarely in breast cancer. The finding of RET mutations in breast cancer is novel. Future tumor biomarker identification directed towards predictive measurement will assist in tailoring therapy to appropriate patient populations.

No significant financial relationships to disclose.

Hematopoietic stem cell mobilization with intravenous melphalan and G-CSF in patients with chemoresponsive multiple myeloma: report of a phase II trial

Multiple myeloma (MM) is an incurable hematologic malignancy for which autologous hematopoietic stem cell transplantation (HCT) is a standard therapy. The optimal method of stem cell mobilization is not defined. We evaluated intravenous melphalan (60 mg/m2), the most effective agent for MM, and G-CSF (10 microg/kg/day) for mobilization. End points were safety, adequacy of CD34+ collections, MM response, and contamination of stem cell components (SCC). In total, 32 patients were mobilized. There were no deaths or significant bleeding episodes; 14 patients (44%) required hospitalization for neutropenic fever. Median days of grade 3 or 4 neutropenia or thrombocytopenia were 7 (2-20) and 8 (3-17). Median mobilization days, CD34+ cells/kg and total leukaphereses were 16 (12-30), 12.1 million (2.6-52.8), and 2 (1-5) respectively. Four patients (12.5 %) failed to achieve the target of 4 million CD34+ cells/kg in five leukaphereses. Reduction in myeloma was seen in 11 patients (34%) with 3 (9%) achieving complete response; 15 (47%) maintained prior responses. Estimated MM contamination per SCC (N=48) was 0.0009% (range 0-0.1) and 0.21 x 10(4) cells per kg (range 0-41.2). Increased contamination was associated with increased patient age. This strategy for mobilization is feasible, frequently requires hospitalization and transfusion, and controls disease in most patients.

Molecular biology of leukemia

Identification and characterization of leukemia-related chromosomal translocations have had significant impact on all aspects of the management of acute leukemia, including its diagnosis, assignment of prognosis, and development of an appropriate treatment plan. Several genes are recurrent targets of chromosomal abnormalities, suggesting that they play a key role in leukemogenesis. Significant progress has been made to define potentially unifying molecular mechanisms of leukemic transformation. Hopefully, these findings will provide the basis for molecularly targeted therapies for leukemia.

Characterization of the soluble human granulocyte-macrophage colony-stimulating factor receptor complex

The human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GM-R) is expressed on both hematopoietic and non-hematopoietic tissues. Although the receptor has been identified by cross-linking studies as an 84,000-dalton protein, very little is known about its biochemistry. In this report, we describe a soluble binding assay for the human GM-R which allowed us to characterize the receptor complex from various sources, including plasma membranes of placenta, neutrophils, and human myeloid leukemia cell lines. Preparation of membranes as well as solubilization by Triton X-100 and N-octylglucoside resulted in a 5-10-fold lower affinity of the receptor for GM-CSF. The Kd decreased from 20 to 80 pM in intact cells to 200-500 pM in both intact and solubilized membranes. Binding in solution was rapid, specific for GM-CSF, and best fit a "one-site" model with an approximate Kd of 500 pM. The dissociation rate constant for the soluble GM-R was very similar to that of intact cells (k2 = 0.013 min-1 versus 0.017 min-1, respectively). As expected, solubilized membranes obtained from those cells expressing the highest number of GM-R (neutrophils and dimethyl sulfoxide-induced HL-60 cells; approximately 500-800 sites/cell) possessed the highest concentration of soluble GM-R (approximately 2-3 x 10(8) GM-R/micrograms). Cross-linking of 125I-GM-CSF to soluble GM-R resulted in the appearance of two specifically labeled complexes. A major 110-kDa receptor-ligand complex is found when cross-linking is performed with intact cells; both 110- and 200-kDa species are seen when cross-linking is performed with either intact membranes or soluble GM-R. These studies define methods by which intact GM-R can be solubilized and measured in solution, permitting a more complete biochemical characterization of the intact GM-R complex.

Human granulocyte colony-stimulating factor: biologic activities and receptor characterization on hematopoietic cells and small cell lung cancer cell lines

Human granulocyte colony-stimulating factor (G-CSF) is a regulatory glycoprotein that stimulates the production of neutrophilic granulocytes from committed hematopoietic progenitor cells both in vitro and in vivo. In this report, we show that biosynthetic (recombinant) human G-CSF enhances colony formation by normal human bone marrow and the human myeloid leukemic cell lines, HL-60 and KG-1, as well as nonhematopoietic small cell lung cancer lines, H128 and H69. G-CSF also modulates multiple differentiated functions of human neutrophils, including enhanced oxidative metabolism in response to f-Met-Leu-Phe (f-MLP), increased antibody-dependent cell-mediated cytotoxicity (ADCC), and augmented arachidonic acid release in response to ionophore and chemotactic agents. These effects are all maximal at a concentration of 100 to 500 pmol/L. Using 125I-labeled recombinant human G-CSF, high affinity binding sites were identified on human neutrophils, the myeloid leukemia cell lines KG-1 and HL-60, and the small cell carcinoma cell lines, H128 and H69. G-CSF receptor numbers ranged between 138 and 285 sites per cell with a kd of 77 to 140 pmol/L, consistent with the concentrations of G-CSF that elicit biologic responses in vitro. Decreased specific binding of 125l-G-CSF by human neutrophils was consistently observed in the presence of excess unlabeled human granulocyte-macrophage colony-stimulating factor (GM-CSF), suggesting competition or down modulation by GM-CSF of the G-CSF receptor.