THU0329 SAFETY, TARGET ENGAGEMENT, AND INITIAL EFFICACY OF AVID200, A FIRST-IN-CLASS POTENT AND ISOFORM-SELECTIVE INHIBITOR OF TGF-BETA 1 AND 3, IN PATIENTS WITH DIFFUSE CUTANEOUS SYSTEMIC SCLEROSIS (DCSSC): A PHASE 1 DOSE ESCALATION STUDY

Background:

AVID200 is a novel, potent TGF-beta receptor ectodomain-based trap designed to selectively neutralize TGF-beta 1 and 3. These two isoforms have been implicated as central mediators of the pathogenesis of systemic sclerosis (SSc). AVID200 avoids inhibition of TGF-beta 2, the isoform that supports normal cardiac function and hematopoiesis.

Objectives:

This first-in-human study (AVID200-01;NCT03831438) is a Phase 1, open label, multicenter, cohort dose-escalation trial designed to evaluate safety, tolerability, pharmacokinetic (PK) profile, pharmacodynamic (PD) effects, target engagement, and preliminary efficacy in patients with diffuse cutaneous SSc (dcSSc).

Methods:

Eligible patients must have dcSSc of <5 years (y) duration and a modified Rodnan Skin Score (MRSS) ≥15. AVID200 at dose levels of 1, 3, 9, or 15 mg/kg IV is administered every 2 weeks (Q2W) for 6 weeks (3 doses). Patients tolerating dosing and who have not experienced disease worsening during the initial Treatment Period may receive up to 6 additional doses Q2W (Extension Period). The ability of AVID200 to selectively sequester its target is assessed in plasma by TGF-beta quantification per ELISA and a cell-based functional readout. Expression of biomarkers of TGF-beta inhibition and genes correlating with MRSS are assessed.

Results:

The first 2 dose cohorts have completed treatment: male/female 3 each, median age 61y (range 45-70), median MRSS at baseline 31 (range 23-39). Recruitment into cohort 3 is complete. AVID200 was well tolerated with no dose limiting toxicities or serious adverse events (SAEs). AEs, all considered possibly related, included single cases of Grade 1 dizziness and CPK elevation, and Grade 2 anemia. All patients demonstrated a decline in MRSS at 6 weeks by 3, 4, and 9 points in Cohort 1, and 2, 8, and 9 points in Cohort 2. Four of 6 patients demonstrated continued decrease in MRSS 12 weeks after the last dose, with all patients showing a decline in MRSS relative to baseline at this timepoint by 7, 6, and 7 points in Cohort 1 and 4, 8, and 13 points in Cohort 2. AVID200 in plasma engaged endogenous activated TGF-beta and potently neutralized signaling from exogenous TGF-beta 1 and 3, but not TGF-beta 2, across the treatment period. PD effects in skin biopsies, including expression of markers of SSc activity, TGF-beta activity, and myofibroblast-associated genes were assessed. Five of 6 patients showed decreased expression of PD biomarker genes, THBS1 and MS4A4A, comparing end of treatment biopsies to baseline, and all patients showed a decline in SERPINE1 expression, a marker gene for TGF-beta activity. Clustering of RNA-seq expression data showed close coregulation of COMP, THBS1, SERPINE1, LOXL, COL10A1, COL11A1, COL12A1, CTGF, and CDH11, suggesting that blocking TGF-beta inhibits this group of profibrotic genes. Single-cell sequencing data show that expression of these genes is upregulated by subsets of SSc fibroblasts.

Conclusion:

AVID200 at doses of 1 and 3 mg/kg was well-tolerated in this first study in dcSSc patients. Evidence of anti-fibrotic effects as indicated by rapid, persistent and clinically meaningful declines in MRSS was observed in all patients, as well as AVID200 target engagement and modulation. Recruitment into additional dose and extension cohorts is ongoing. Together, these clinical data support selective TGF-beta 1 and 3 inhibition by AVID200 as a promising therapeutic approach for dcSSc.

Disclosure of Interests:

Robert Lafyatis Grant/research support from: Forbius, Consultant of: Certa Therapeutics, Forbius, FBM Therapeutics, Robert Spiera Grant/research support from: Roche-Genetech, GSK, Boehringer Ingelheim, Chemocentryx, Corbus, Forbius, Sanofi, Inflarx, Consultant of: Roche-Genetech, GSK, CSL Behring, Sanofi, Janssen, Chemocentryx, Forbius, Mistubishi Tanabe, Robyn Domsic Consultant of: Forbius, Anna Papazoglou: None declared, Colin Ligon Grant/research support from: Forbius, Christina Mae Zinger Morse: None declared, Jean-François Denis Employee of: Forbius, Margaret Davis Employee of: Forbius, Tina Gruosso Employee of: Forbius, Gilles Tremblay Employee of: Forbius, Maureen O’Connor McCourt Employee of: Forbius, Sandra Sinclair Employee of: Forbius, Jonathan Delara Employee of: Forbius, Krista Alvarado Employee of: Forbius, Debra Wood Consultant of: Forbius, Symphogen, Paul Nadler Consultant of: Forbius, Symphogen, Karyopharm, Elizabeth Volkmann Grant/research support from: Forbius, Corbus Pharmaceuticals, Consultant of: Boehringer Ingelheim, Forbius, Speakers bureau: Boehringer Ingelheim

Abstract P4-06-03: Unravelling triple-negative breast cancer tumor microenvironment heterogeneity using an integrative multiomic analysis

Introduction: Triple negative breast cancer (TNBC) constitute 10-20% of all breast cancers and is associated with a worse prognosis and limited treatment options. Recent trials evaluating immune checkpoint blockade in TNBC demonstrated encouraging results for a subset of patients. TNBC is highly heterogeneous and its tumour microenvironment (TME) has been recognized as a critical determinant of its behavior and clinical outcome. Genome-wide gene expression profiling analyses have already improved our understanding of the complexity of this disease and have defined 6 different molecular subtypes namely Basal-like 1 (BL1), basal-like 2 (BL2), immunomodulatory (IM), mesenchymal (M), mesenchymal stem-like (MSL) and luminal androgen receptor (LAR), exhibiting distinct biological and clinical characteristic.

In this study, we aim to dissect the molecular diversity of the TME and more specifically to assess the immune landscape according to TNBC molecular subtypes.

Methods: A cohort of 485 TNBC patient with publicly available data (RNA-Seq and Illumina HT-12 v3) from the METABRIC and the TCGA consortia were used in the gene expression analysis. Gene signatures reflecting different features or cellular components (immune, stromal, angiogenesis, lymphangiogenesis, hypoxia, metabolism) of the TME were used to evaluate multiple biological processes known to contribute to tumorogenesis. A compendium of 17 immune specific gene signatures and T cell localisation classification were used to evaluate the immune composition and spatial pattern of immune infiltrates. All parameters were compared using a logistic regression model to evaluate their relative contribution according to each molecular subtype.

Results: Our analyses demonstrated that each molecular subtype exhibits different TME profiles, as well as specific immune composition and localisation. IM tumors were associated with the highest expression of immune-related gene signatures, enriched with adaptive immune cells and with a fully inflamed spatial pattern. MSL tumors were mostly associated with the expression of Lymphangiogenesis and Stromal TME signatures. They also exhibited some immune activity through the expression of immune gene signatures capturing innate immune and adaptive immunosuppressive cells. This subtype was mainly associated with margin restricted and to some extent with fully inflamed spatial pattern. BL1 tumors were associated with the expression of Metabolism TME signatures, along with fully inflamed and stroma restricted spatial pattern. To a lesser extent, this subtype was also associated with activated DC and CD4 Tem cells. LAR and M tumors exhibited an immune cold phenotype. They were associated with Stromal and Metabolism TME signatures, enriched in margin restricted spatial pattern and negatively associated with every immune cells.

Conclusions: Our results demonstrate for the first time the huge heterogeneity that characterizes the TME of TNBCs. Identification of specific TME profiles could help to design more rationale and appropriate synergistic therapeutic combinations targeting TME elements in this high-risk disease.

Citation Format: Bareche Y, Buisseret L, Gruosso T, Girard E, Venet D, Dupont F, Desmedt C, Park M, Rothé F, Stagg J, Sotiriou C. Unravelling triple-negative breast cancer tumor microenvironment heterogeneity using an integrative multiomic analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-03.

Abstract PD6-05: Distinct tumor microenvironments stratify triple negative breast cancer into immune subtypes

Background:

Triple negative breast cancer (TNBC) are especially difficult to treat effectively. While only 20-30% of TNBC patients respond to chemotherapy in the neoadjuvant setting, overall outcome remains poor for non-responding patients. Engaging the immune system promises optimal personalized cancer therapy as mounting evidence suggests that immune-checkpoint inhibitor immunotherapies may become a therapeutic option for TNBC patients. The presence of CD8+ T cells, a crucial component of the cytotoxic arm of the adaptive immune response, is associated with good clinical outcome in TNBC patients. Specifically, it is the efficient CD8+ T cell invasion and infiltration in the tumor that is associated with good outcome. On the other hand, some tumors accumulate CD8+ T cells in the tumor-associated stroma with poor infiltration in the tumor epithelium. These patients show poor outcome. As CD8+ T cell infiltration in the tumor is a crucial step to mount an efficient anti-tumor response, we thus wondered how the tumor microenvironment affects CD8+ T cell invasion into the tumor epithelial compartment of the TNBC tumors.

Methods:

To identify potential stroma-dependent mechanisms that potentiate or inhibit CD8+ T cells invasion into the tumor epithelium, we coupled analysis of spatial patterns of CD8+ T cell localization by Immunohistochemistry (IHC) andperformed gene expression profiling of laser-capture microdissected tumor-associated stroma (as well as matched epithelium and bulk tumor) from 38 TNBC chemotherapy-naive primary cases. GSEA-based Metasignatures were derived from bulk tumor gene expression data from our cohort. To investigate the compartment of origin of the pathways identified via the Metasignatures, the (LCM)-derived tumor stromal and epithelial gene expression were analyzed.

Results:

CD8+ T cell quantification in different compartments of the tumor identify 3 main subgroups of TNBC based on CD8+ T cell localization. Importantly we developed a 2-step classification scheme based on CD8+ T cell localization. We developed metasignatures following our 2 steps classification and identified key bulk tumor metasignatures that showed prognostic value in an independent cohort. In addition the matched LCM gene expression from the tumor epithelium and stromal compartments allowed us to identify the compartment of origin.

Importantly, while 1 group of TNBC tumor was showing a significant anti-tumor response, the 2 other groups showed absence of such environment. The 2 non inflamed immune subtypes showed distinct phenotypes and biologies associated with poor anti-tumor response that we validated by immunohistochemistry and fluorescence. These results highlight different potential mecanisms that lead to immune evasion and allow us to stratify TNBC into immune subgroups.

Citation Format: Gruosso T, Gigoux M, Bertos N, Manem VS, Zuo D, Saleg SM, Souleimanova M, Zhao H, Johnson RM, Monette A, Muñoz Ramos V, Hallett MT, Stagg J, Lapointe R, Omeroglu A, Meterissian S, Buisseret L, Van den Eyden G, Salgado R, Guiot M-C, Haibe-Kains B, Park M. Distinct tumor microenvironments stratify triple negative breast cancer into immune subtypes [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD6-05.

Abstract P4-03-08: Mechanisms of CD8+ T cell immunosuppression in triple negative breast cancer

Triple negative breast cancer (TNBC), defined as tumors lacking expression of the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), are especially difficult to treat effectively. While ER+ and HER2+ breast cancer subtypes can be treated with Tamoxifen and Herceptin, respectively, there are no targeted therapies for TNBC patients. Furthermore, while only 20-30% of TNBC patients respond to chemotherapy in the neoadjuvant setting, overall outcome remains poor for non-responding patients. However, mounting evidence suggests that immune-checkpoint inhibitor immunotherapies may be especially promising for TNBC patients. We and others have shown that the presence of CD8+ T cells, a crucial component of the cytotoxic arm of the adaptive immune response, is a sign of good clinical outcome in TNBC patients. However, good outcome only correlates with CD8 +T cell invasion of the tumor parenchyma. Some patients had an accumulation of CD8+ T cells in the surrounding tumor-associated stroma, but not the tumor epithelia, and these patients responded as poorly as patients with no CD8 T cells at all. Yet how cancer associated fibroblasts (CAFs), the dominant cell type of the tumor-associated stroma, affects CD8+ T cell invasion into the tumor epithelia is still poorly understood. To identify potential stroma-dependent mechanisms which potentiate or inhibit CD8+ T cells invasion into the tumor epithelia, we performed gene expression profiling of laser-capture microdissected tumor-associated stroma (and matched epithelia) from 38 TNBC cases. Here we identify several stromal and epithelial canonical pathways as well as biomarkers that are associated with and may explain the accumulation of CD8 T cells outside of the tumor epithelia.

Citation Format: Gruosso T, Gigoux M, Bertos N, Zuo D, Manem V, Monette A, Lapointe R, Haibe-Kains B, Park M. Mechanisms of CD8+ T cell immunosuppression in triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-03-08.

Ovarian cancer emerging subtypes: role of oxidative stress and fibrosis in tumour development and response to treatment

Epithelial ovarian cancer is a silent disease of usually late diagnosis and poor prognosis. Currently treatment options are limited and mainly consist of surgery followed by taxol- and platinum-based chemotherapy. Patient response to treatment is difficult to predict and there is a serious need for anticipating tumour response and orientating medical choices. In that aim, recent researches have focused on molecular aspects of ovarian tumours that could help patient stratification. We review here published discoveries in that field. We emphasize that signatures, defined by combining miRNA and transcriptomic data, enlighten important aspects of ovarian cancer biology and reliably stratify patients. The miR-200-dependent "Oxidative stress" and "Fibrosis" signatures are promising in patient stratification for defining oriented therapeutic strategies. Indeed, the "Stress" patients survive longer than the "Fibrosis" patients, who exhibit partial debulking and incomplete response to chemotherapy. Interestingly, these two subgroups might benefit from specifically targeted therapeutic approaches, as discussed here.