Glucocorticoid Receptor Modulators Research Articles

Neuroprotective efficacy of the glucocorticoid receptor modulator PT150 in the rotenone mouse model of Parkinson’s disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder worldwide. Current treatments for PD largely center around dopamine replacement therapies and fail to prevent the progression of pathology, underscoring the need for neuroprotective interventions. Approaches that target neuroinflammation, which occurs prior to dopaminergic neuron (DAn) loss in the substantia nigra (SN), represent a promising therapeutic strategy. The glucocorticoid receptor (GR) has been implicated in the neuropathology of PD and modulates numerous neuroinflammatory signaling pathways in the brain. Therefore, we investigated the neuroprotective effects of the novel GR modulator, PT150, in the rotenone mouse model of PD, postulating that inhibition of glial inflammation would protect DAn and reduce accumulation of neurotoxic misfolded ⍺-synuclein protein. C57Bl/6 mice were exposed to 2.5 mg/kg/day rotenone by intraperitoneal injection for 14 days. Upon completion of rotenone dosing, mice were orally treated at day 15 with 30 mg/kg/day or 100 mg/kg/day PT150 in the 14-day post-lesioning incubation period, during which the majority of DAn loss and α-synuclein (α-syn) accumulation occurs. Our results indicate that treatment with PT150 reduced both loss of DAn and microgliosis in the nigrostriatal pathway. Although morphologic features of astrogliosis were not attenuated, PT150 treatment promoted potentially neuroprotective activity in these cells, including increased phagocytosis of hyperphosphorylated α-syn. Ultimately, PT150 treatment reduced the loss of DAn cell bodies in the SN, but not the striatum, and prohibited intra-neuronal accumulation of α-syn. Together, these data indicate that PT150 effectively reduced SN pathology in the rotenone mouse model of PD.

Abstract PO-006: ABBV-319: A CD19–targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies

Abstract Glucocorticoids such as prednisone (P) and dexamethasone (D) are key components in standard-of-care immuno-chemotherapy regimens (e.g., R-CHOP, EPOCH-R, Hyper-CVAD) for the treatment of B-cell malignancy. However, prolonged systemic glucocorticoid treatment is associated with several adverse events that often result in dose reduction and reduced therapeutic efficacy. ABBV-319 is a CD19-targeting antibody-drug conjugate (ADC) with a glucocorticoid receptor modulator (GRM) payload engineered to reduce glucocorticoid-associated toxicities while possessing three distinct mechanisms of action (MOA) to increase therapeutic efficacy: (1) CD19 receptor-mediated delivery of potent glucocorticoid receptor modulator (GRM) payload to induce apoptosis, (2) inhibition of B-cell receptor (BCR) stimulated CD19 signaling, and (3) enhanced Fc-mediated effector function via afucosylation of the antibody backbone. ABBV-319 elicited potent GRM-driven anti-tumor activity against multiple malignant B-cell lines in vitro as well as in cell line-derived xenografts (CDXs) and patient-derived xenografts (PDXs) in vivo. Remarkably, a single-dose of ABBV-319 induced sustained tumor regression and enhanced anti-tumor activity compared to repeat dosing of systemic prednisolone at the maximum tolerated dose (MTD) in mice. The unconjugated CD19 monoclonal antibody (mAb) also displayed anti-proliferative activity on a subset of B-cell lymphoma cell lines through the inhibition of PI3K signaling. Moreover, afucosylation of the CD19 mAb enhanced Fc-mediated antibody-dependent cellular cytotoxicity (ADCC), and this activity was maintained after conjugation with GRM payload. Notably, ABBV-319 displayed superior efficacy compared to afucosylated CD19 mAb in human CD34+ PBMC-engrafted NSG-tg(Hu-IL15) transgenic mice, demonstrating enhanced anti-tumor activity in vivo when multiple MOAs are enabled concurrently. ABBV-319 also showed potent anti-tumor activity across multiple B-cell lymphoma models, including non-germinal center B-cell (GCB) DLBCL and relapsed lymphoma treated with R-CHOP treatment. Collectively, these data support the ongoing evaluation of ABBV-319 for the treatment of B-cell malignancy in Phase I clinical trial (NCT05512390). Disclosures: All authors are employees of AbbVie. The design, study conduct, and financial support for this research were provided by AbbVie. AbbVie participated in the interpretation of data, review, and approval of the publication. Citation Format: Chewei (Anderson) Chang. ABBV-319: A CD19–targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-006.

Anti-TNF Thioester Glucocorticoid Antibody-Drug Conjugate Fully Inhibits Inflammation with Minimal Effect on Systemic Corticosterone Levels in a Mouse Arthritis Model.

We describe the discovery of a thioester-containing glucocorticoid receptor modulator (GRM) payload and the corresponding antibody-drug conjugate (ADC). Payload 6 was designed for rapid hepatic inactivation to minimize systemic exposure of nonconjugated GRM. Mouse PK indicated that 6 is cleared 10-fold more rapidly than a first-generation GRM payload, resulting in 10-fold lower exposure and 3-fold decrease in Cmax. The anti-mTNF conjugate ADC5 fully inhibited inflammation in mouse contact hypersensitivity with minimal effects on corticosterone, a biomarker for systemic GRM effects, at doses up to and including 100 mg/kg. Concomitant inhibition of P1NP suggests potential delivery to cells involved in the remodeling of bone, which may be a consequence of TNF-targeting or bystander payload effects. Furthermore, ADC5 fully suppressed inflammation in collagen-induced arthritis mouse model after one 10 mg/kg dose for 21 days. The properties of the anti-hTNF conjugate were suitable for liquid formulation and may enable subcutaneous dosing.

ABBV-319: a CD19-targeting glucocorticoid receptor modulator antibody-drug conjugate therapy for B-cell malignancies

AbstractGlucocorticoids are key components of the standard-of-care treatment regimens for B-cell malignancy. However, systemic glucocorticoid treatment is associated with several adverse events. ABBV-319 is a CD19-targeting antibody-drug conjugate engineered to reduce glucocorticoid-associated toxicities while possessing 3 distinct mechanisms of action (MOA) to increase therapeutic efficacy: (1) antibody-mediated delivery of a glucocorticoid receptor modulator (GRM) payload to activate apoptosis, (2) inhibition of CD19 signaling, and (3) enhanced fragment crystallizable (Fc)–mediated effector function via afucosylation of the antibody backbone. ABBV-319 elicited potent GRM-driven antitumor activity against multiple malignant B-cell lines in vitro, as well as in cell line-derived xenografts and patient-derived xenografts (PDXs) in vivo. Remarkably, a single dose of ABBV-319 induced sustained tumor regression and enhanced antitumor activity compared with repeated dosing of systemic prednisolone at the maximum tolerated dose in mice. The unconjugated CD19 monoclonal antibody (mAb) also displayed antiproliferative activity in a subset of B-cell lymphoma cell lines through the inhibition of phosphoinositide 3-kinase signaling. Moreover, afucosylation of CD19 mAb enhanced Fc-mediated antibody-dependent cellular cytotoxicity. Notably, ABBV-319 displayed superior efficacy compared with afucosylated CD19 mAb in human CD34+ peripheral blood mononuclear cell–engrafted NSG-Tg(Hu-IL15) transgenic mice, demonstrating enhanced antitumor activity when multiple MOAs are enabled. ABBV-319 also showed durable antitumor activity across multiple B-cell lymphoma PDX models, including nongerminal center B-cell diffuse large B-cell lymphoma and relapsed lymphoma after R-CHOP treatment. Collectively, these data support the ongoing evaluation of ABBV-319 in a phase 1 clinical trial.

The effect of AZD9567 vs. prednisolone on glycaemic control in patients with type 2 diabetes mellitus: Results from a phase 2a clinical trial.

Corticosteroids are the treatment of choice for many inflammatory diseases but often lead to adverse effects, including hyperglycaemia. This study investigated the mechanisms driving differential effects on glucose control for AZD9567, an oral nonsteroidal selective glucocorticoid receptor modulator vs. prednisolone in 46 patients with type 2 diabetes mellitus. In this randomized, double-blind, 2-way cross-over study (NCT04556760), participants received either AZD9567 72 mg and prednisolone 40 mg daily (cohort 1); AZD9567 40 mg and prednisolone 20 mg daily (cohort 2); or placebo and prednisolone 5mg daily (cohort 3). Treatment duration was 3days with a 3-week washout between treatment periods. Glycaemic control was assessed after a standardized meal and with continuous glucose monitoring. A significant difference between AZD9567 and prednisolone in favour of AZD9567 was observed for the change from baseline to Day 4 glucose excursions postmeal in cohort 1 (glucose area under the curve from 0 to 4h -4.54%; 95% confidence interval [CI]: -8.88, -0.01; P = .049), but not in cohort 2 (-5.77%; 95% CI: -20.92, 12.29; P = .435). In cohort 1, significant differences between AZD9567 and prednisolone were also seen for the change from baseline to day 4 in insulin and glucagon secretion postmeal (P < .001 and P = .005, respectively) and change from baseline to Day 4 in GLP-1 response (P = .022). Significant differences between AZD9567 and prednisolone for 24-h glucose control were observed for both cohort 1 (-1.507 mmol/L; 95% CI: -2.0820, -0.9314; P < .001) and cohort 2 (-1.110 mmol/L; 95% CI -1.7257, -0.4941; P < .001). AZD9567 significantly reduced treatment-induced hyperglycaemia compared with prednisolone.

Vamorolone: revolutionizing Duchenne muscular dystrophy treatment

Duchenne muscular dystrophy (DMD) is a severe inherited neuromuscular disorder characterized by a dystrophin gene mutation, leading to progressive muscle weakness and structural degradation. Current management strategies focus on multidisciplinary approaches to mitigate symptoms and enhance quality of life. Conventional glucocorticoids present challenges due to their complex nature and severe side effects. Vamorolone, a first-in-class dissociative steroidal drug recently Food and Drug Administration (FDA) - approved, distinguishes itself through enduring anti-inflammatory effects with reduced safety concerns. Pharmacologically, Vamorolone's mechanism of action, differentiating it from traditional corticosteroids, involves selective glucocorticoid receptor (GR) modulation and mineralocorticoid receptor (MR) antagonism, offering improved safety and tolerability. Notably, its unique Δ9,11 modification prevents adverse receptor interactions, demonstrating superior safety in inhibiting inflammation across various cell types. This article explores Vamorolone's pharmacokinetics, drug interactions, and adverse effects, underscoring its well-tolerated profile with reversible hypothalamic-pituitary-adrenal axis suppression as a notable concern. Comparative studies against prednisone reveal Vamorolone's efficacy in improving muscle strength with minimal side effects, validated through the pivotal Phase IIb VISION-DMD study. Ultimately, Vamorolone has attained a breakthrough status in DMD treatment. Its endorsement by the FDA underscores Vamorolone as a transformative linchpin, heralding a new era in revolutionizing DMD care.

Characterization of a new selective glucocorticoid receptor modulator with anorexigenic activity

Obesity, a worldwide epidemic, leads to various metabolic disorders threatening human health. In response to stress or fasting, glucocorticoid (GC) levels are elevated to promote food intake. This involves GC-induced expression of the orexigenic neuropeptides in agouti-related protein (AgRP) neurons of the hypothalamic arcuate nucleus (ARC) via the GC receptor (GR). Here, we report a selective GR modulator (SGRM) that suppresses GR-induced transcription of genes with non-classical glucocorticoid response elements (GREs) such as Agrp-GRE, but not with classical GREs, and via this way may serve as a novel anti-obesity agent. We have identified a novel SGRM, 2-O-trans-p-coumaroylalphitolic acid (Zj7), a triterpenoid extracted from the Ziziphus jujube plant, that selectively suppresses GR transcriptional activity in Agrp-GRE without affecting classical GREs. Zj7 reduces the expression of orexigenic genes in the ARC and exerts a significant anorexigenic effect with weight loss in both high fat diet-induced obese and genetically obese db/db mouse models. Transcriptome analysis showed that Zj7 represses the expression of a group of orexigenic genes including Agrp and Npy induced by the synthetic GR ligand dexamethasone (Dex) in the hypothalamus. Taken together, Zj7, as a selective GR modulator, showed beneficial metabolic activities, in part by suppressing GR activity in non-classical GREs in orexigenic genes. This study demonstrates that a potential anorexigenic molecule may allow GRE-specific inhibition of GR transcriptional activity, which is a promising approach for the treatment of metabolic disorders.

A Phase I Trial of Enzalutamide Plus Selective Glucocorticoid Receptor Modulator Relacorilant in Patients with Metastatic Castration-Resistant Prostate Cancer.

The majority of patients with metastatic prostate cancer who receive androgen-deprivation therapy and androgen receptor (AR) signaling inhibitors (ARSI) progress. Activation of the glucocorticoid receptor (GR) is associated with ARSI resistance. This single-arm phase I trial assessed safety and pharmacokinetic (PK) feasibility of a combined AR antagonist (enzalutamide) and selective GR modulator (relacorilant) in patients with metastatic castration-resistant prostate cancer (mCRPC). This was a phase I trial (NCT03674814) of relacorilant and enzalutamide in patients with refractory mCRPC enrolled using a 6+3 design. The enzalutamide dose was kept constant at 120 mg/d with escalating doses of relacorilant based on safety and PK measures in cohorts of ≥6 patients. The primary objective was safety and establishment of pharmacologically active doses. Secondary objectives were related to antitumor activity. Thirty-five patients with mCRPC were enrolled. Twenty-three were accrued across three dose cohorts in the dose-escalation phase, and 12 enrolled at the recommended phase II dose. The combination was generally well tolerated, safe, and achieved desirable enzalutamide PK. RP2D of 120 + 150 mg/d, respectively, was established. Median time on study was 2.2 months with four patients remaining on study for longer than 11 months. Four of 12 evaluable patients had a prostate-specific antigen (PSA) partial response. This is the first prospective trial combining an AR antagonist and a nonsteroidal selective GR modulator. The combination was safe and well tolerated with PSA response and prolonged disease control observed in a limited subset of patients. Further prospective trials are justified to evaluate efficacy and identify predictive biomarkers of response.

An anti-TNF-glucocorticoid receptor modulator antibody-drug conjugate is efficacious against immune-mediated inflammatory diseases.

Glucocorticoids (GCs) are efficacious drugs used for treating many inflammatory diseases, but the dose and duration of administration are limited because of severe side effects. We therefore sought to identify an approach to selectively target GCs to inflamed tissue. Previous work identified that anti-tumor necrosis factor (TNF) antibodies that bind to transmembrane TNF undergo internalization; therefore, an anti-TNF antibody-drug conjugate (ADC) would be mechanistically similar, where lysosomal catabolism could release a GC receptor modulator (GRM) payload to dampen immune cell activity. Consequently, we have generated an anti-TNF-GRM ADC with the aim of inhibiting pro-inflammatory cytokine production from stimulated human immune cells. In an acute mouse model of contact hypersensitivity, a murine surrogate anti-TNF-GRM ADC inhibited inflammatory responses with minimal effect on systemic GC biomarkers. In addition, in a mouse model of collagen-induced arthritis, single-dose administration of the ADC, delivered at disease onset, was able to completely inhibit arthritis for greater than 30 days, whereas an anti-TNF monoclonal antibody only partially inhibited disease. ADC treatment at the peak of disease was also able to attenuate the arthritic phenotype. Clinical data for a human anti-TNF-GRM ADC (ABBV-3373) from a single ascending dose phase 1 study in healthy volunteers demonstrated antibody-like pharmacokinetic profiles and a lack of impact on serum cortisol concentrations at predicted therapeutic doses. These data suggest that an anti-TNF-GRM ADC may provide improved efficacy beyond anti-TNF alone in immune mediated diseases while minimizing systemic side effects associated with standard GC treatment.

Selective Modulation of the Human Glucocorticoid Receptor Compromises GR Chromatin Occupancy and Recruitment of p300/CBP and the Mediator Complex

Exogenous glucocorticoids are frequently used to treat inflammatory disorders and as adjuncts for the treatment of solid cancers. However, their use is associated with severe side effects and therapy resistance. Novel glucocorticoid receptor (GR) ligands with a patient-validated reduced side effect profile have not yet reached the clinic. GR is a member of the nuclear receptor family of transcription factors and heavily relies on interactions with coregulator proteins for its transcriptional activity. To elucidate the role of the GR interactome in the differential transcriptional activity of GR following treatment with the selective GR agonist and modulator dagrocorat compared to classic (ant)agonists, we generated comprehensive interactome maps by high-confidence proximity proteomics in lung epithelial carcinoma cells. We found that dagrocorat and the antagonist RU486 both reduced GR interaction with CREB-binding protein/p300 and the mediator complex compared to the full GR agonist dexamethasone. Chromatin immunoprecipitation assays revealed that these changes in GR interactome were accompanied by reduced GR chromatin occupancy with dagrocorat and RU486. Our data offer new insights into the role of differential coregulator recruitment in shaping ligand-specific GR-mediated transcriptional responses.

Clinical Trial Protocol for ROSELLA: a phase 3 study of relacorilant in combination with nab-paclitaxel versus nab-paclitaxel monotherapy in advanced platinum-resistant ovarian cancer.

Ovarian cancer has the highest mortality among gynecologic cancers, primarily because it typically is diagnosed at a late stage and because of the development of chemoresistance in recurrent disease. Improving outcomes in women with platinum-resistant ovarian cancer is a substantial unmet need. Activation of the glucocorticoid receptor (GR) by cortisol has been shown to suppress the apoptotic pathways used by cytotoxic agents, limiting their efficacy. Selective GR modulation may be able to counteract cortisol's antiapoptotic effects, enhancing chemotherapy's efficacy. A previous phase 2 study has shown that adding intermittently dosed relacorilant, a selective GR modulator, to nab-paclitaxel improved outcomes, including progression-free survival (PFS) and overall survival (OS), with minimal added toxicity, in women with recurrent platinum-resistant ovarian cancer. The ROSELLA study aims to confirm and expand on these findings in a larger population. ROSELLA is a phase 3, randomized, 2-arm, open-label, global multicenter study in women with recurrent, platinum-resistant, high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancer. Eligible participants have received 1 to 3 lines of prior systemic anticancer therapy, including ≥1 prior line of platinum therapy and prior treatment with bevacizumab, with documented progressive disease or intolerance to the most recent therapy. There is no biomarker-based requirement for participant selection. Participants are randomized 1:1 to receive intermittently dosed relacorilant in combination with nab-paclitaxel or nab-paclitaxel monotherapy. The study's primary efficacy endpoint is PFS as assessed by blinded independent central review. Secondary efficacy endpoints include OS, investigator-assessed PFS, objective response rate, best overall response, duration of response, clinical benefit rate at 24 weeks, and cancer antigen 125 response. The study is also evaluating safety and patient-reported outcomes. ClinicalTrials.gov Identifier: NCT05257408; European Union Drug Regulating Authorities Clinical Trials Database Identifier: 2022-000662-18.

Minimising the payload solvent exposed hydrophobic surface area optimises the antibody-drug conjugate properties.

Glucocorticoid receptor modulators (GRMs) are an established and successful compound class for the treatment of multiple diseases. In addition, they are an area of high interest as payloads for antibody-drug conjugate s(ADCs) in both immunology and oncology. Solving the crystal structure of compound 2, the GRM payload from ABBV-3373 and ABBV-154, in the ligand binding domain of the glucocorticoid receptor (GR) revealed key information to facilitate optimal ADC payload design. All four critical H-bonds between the oxygen functional groups on the hexadecahydro-1H-cyclopenta[a]phenanthrene ring system of the small molecule and protein were shown to be made (carbonyl at C3 to Gln570 and Arg611 and Asn564, carbonyl at C20 to Thr739, hydroxyl at C21 to Asn 564 and Thr739). In addition, an extra H-bond between the linker attachment site on compound 2, the aniline in the biaryl region, was observed. Confirmation of the stereochemistry of the acetal in compound 2 as (R) was established. Finally, the importance of minimising the exposed hydrophobic surface area of a payload to reduce the negative impact on the properties of resulting ADCs, like aggregation, was rationalised by comparison of (R)-acetal compound 2 and (S)-acetal compound 3.

Impact of dipeptide on ADC physicochemical properties and efficacy identifies Ala-Ala as the optimal dipeptide.

Side chains of natural occurring amino acids vary greatly in terms of charge state, polarity, size and hydrophobicity. Using a linear synthetic route, two amino acids were sequentially coupled to a potent glucocorticoid receptor modulator (GRM) to afford a library of dipeptide-GRM linker payloads with a range of in silico properties. The linker payloads were conjugated to a mouse anti-TNF antibody through interchain disulfide Cys. Impact of various dipeptide linkers on ADC physical properties, including solubility, hydrophobicity, and aggregation were evaluated and the in silico properties pI, Log P and tPSA of the linker drugs used to correlate with these properties. ADCs were screened in a GRE luciferase reporter assay to compare their in vitro efficacy. Data identified Ala-Ala as a superior dipeptide linker that allowed a maximum drug load of 10 while affording ADCs with low aggregation.

Impact of atropisomerism on a non-steroidal glucocorticoid receptor agonist.

To investigate atropisomers of non-steroidal glucocorticoid receptor modulator GSK866, a virtual library of substituted benzoic acid analogues was enumerated. Compounds from this library were subjected to a torsion angle scan using Spartan'20 to calculate the torsion rotation energy barrier which identified compounds predicted to be stable as atropisomers. After synthesis of the library, analysis showed that compounds 13 and 14 existed as stable atropisomers 13a, 13b, 14a and 14b, in agreement with the earlier calculations. Screening in a glucocorticoid receptor cellular assay showed that one compound from each atropisomer pair was significantly more potent than the other. Docking in a public structure of the glucocorticoid receptor (PBD code 3E7C) enabled the stereochemistry of the two most potent compounds 13a and 14b to be assigned as (R a) and (S a), respectively.

Protective Effects of AR1001 in Alzheimer’s Disease Models: Polypharmacological Mechanisms

AbstractBackgroundNitric oxide/cGMP/CREB signaling is critical for learning and memory processes and is disturbed by Abeta amyoid and in Alzheimer’s disease. AR1001 is an inhibitor of phosphodiesterase (PDE)‐5, which degrades specifically cGMP, thus having a potential to reverse AD pathology.MethodFor the in vivo study, AR1001 was intraperitoneally administered (4 mg/kg/day) to APP‐C105 mice for 4 weeks. Then after behavioral tests (Morris‐water maze and passive avoidance tests) were done, hippocampal levels of Abeta1‐42 and p‐Tau (S199/202) were determined. In the in vitro study using human neuroblastoma SH‐SY5Y cells and mouse hippocampal HT‐22 cells, the effects of AR1001 on Abeta1‐42‐induced cytotoxicity and intracellular signaling were examined.ResultAR1001 markedly improved cognitive functions in both Morris‐water maze and passive avoidance tests and reduced hippocampal Abeta1‐42 and p‐Tau levels in the APP‐C105 mice. In the in vitro experiments, AR1001 inhibited Abeta1‐42‐induced cell death, mitochondrial membrane potential derangement, and apoptotic markers (cleaved caspase‐3 and cleaved PPAR) concentration‐dependently. AR1001 reversed Abeta1‐42‐induced decrease in phosphorylated CREB (p‐CREB), and NGF/BDNF expression. Further, AR1001 blocked Abeta1‐42‐induced pSer9‐GSK3beta decrease and p25/p35 increase. Interestingly, compared with sildenafil, vardenafil and tadalafil, AR1001 was more effective in inhibiting glucocorticoid receptor (GR) dimerization and Wnt antagonist Dickkopf‐1 (Dkk‐1) expression, and in enhancing Wnt3a expression.ConclusionAR1001 had protective effects both in vivo and in vitro models of AD. Furthermore, AR1001 showed more pronounced activity in the modulation of GR and Wnt signaling among the various PDE‐5 inhibitors. It is suggested that the multimodal activity of AR1001 contributes to the therapeutic effects of AR1001 observed in the phase 2 clinical trial in AD patients (NCT03625622).

Glucocorticoid Receptor (GR) Activation Is Associated with Increased cAMP/PKA Signaling in Castration-Resistant Prostate Cancer.

In castration-resistant prostate cancer (CRPC), increased glucocorticoid receptor (GR) expression and ensuing transcriptional activity have been proposed as an oncogenic "bypass" mechanism in response to androgen receptor (AR) signaling inhibition (ARSi). Here, we report that GR transcriptional activity acquired following ARSi is associated with the upregulation of cyclic adenosine monophosphate (cAMP)-associated gene expression pathways in both model systems and metastatic prostate cancer patient samples. In the context of ARSi, the expression of GR-mediated genes encoding cAMP signaling pathway-associated proteins can be inhibited by treatment with selective GR modulators (SGRMs). For example, in the context of ARSi, we found that GR activation resulted in upregulation of protein kinase inhibitor beta (PKIB) mRNA and protein levels, leading to nuclear accumulation of the cAMP-dependent protein kinase A catalytic subunit (PKA-c). Increased PKA-c, in turn, is associated with increased cAMP response element-binding protein phosphorylation and activity. Furthermore, enzalutamide and SGRM combination therapy in mice bearing CRPC xenografts delayed CRPC progression compared with enzalutamide therapy alone, and reduced tumor PKIB mRNA expression. Supporting the clinical importance of GR/PKA signaling activation in CRPC, we found a significant enrichment of both cAMP pathway signaling-associated gene expression and high NR3C1 (GR) activity in patient-derived xenograft models and metastatic human CRPC samples. These findings suggest a novel mechanism linking CRPC-induced GR transcriptional activity with increased cAMP signaling in AR-antagonized CRPC. Furthermore, our findings suggest that GR-specific modulation in addition to AR antagonism may delay GR+ CRPC time to recurrence, at least in part, by inhibiting tumor cAMP/PKA pathways.

THU475 Ovarian Tumor-cell Glucocorticoid Receptor Activity Modulates Cytokine Secretion Promoting Recruitment And Activation of Immunosuppressive Cells Into The Tumor Microenvironment

Abstract Disclosure: M. Taya: None. E. LeBlanc: None. L. Bennett: None. S.D. Conzen: None. Elevated levels of immunosuppressive myeloid-derived suppressor cells (MDSCs) circulate in the peripheral blood or infiltrate both tumors and ascites in ovarian cancer patients, however the cause for this observed phenotype is unknown. MDSCs contribute to tumor immune tolerance primarily via inhibition of cytotoxic T-cells or by activation of immunosuppressive T-regulatory cells. We previously showed that high tumor cell glucocorticoid receptor (GR) expression is associated with a relatively poor prognosis in ovarian cancer patients. Additionally, using primary tumor data retrieved from the ovarian cancer TCGA dataset, we show high tumor GR expression is associated with significantly higher expression of Foxp3, a marker of immunosuppressive T-regulatory cells, as well as CD33, a marker of immunosuppressive myeloid cells, further suggesting an immunosuppressive phenotype in ovarian cancer patients. We thus hypothesize that tumor-intrinsic GR activation in ovarian cancer is associated with increased MDSC infiltration into the tumor microenvironment partly due to the modulation of tumor cell cytokine secretion. To determine whether tumor-cell GR activation modulates the cytokine secretome, we previously showed that GR activation in ovarian cancer cells upregulates secretion of immunomodulatory factors including G-CSF, TGFb and CXCL5. Moreover, co-treatment of cells with a selective GR modulator (SGRM) reverses this effect. Preliminary gene expression data indicate GR mediated cytokine secretion and signaling may involve post-transcriptional or post-translational mechanisms. Considering that elevated levels of these cytokines are necessary for the production and recruitment of MDSCs, these data highlight the relevance of this evident glucocorticoid receptor-cytokine circuit in ovarian cancer cells. Furthermore, we show that this tumor-cell cytokine secretome has the capacity to promote differentiation of MDSCs from precursor myeloid cells in healthy PBMCs. Importantly, measuring expression of activation markers such as Arginase-1 and NOS2 illustrated that these MDSCs are in their functional state. To our knowledge, this is the first evidence that a nuclear receptor in ovarian cancer tumor cells is actively driving MDSC differentiation. Finally, employing ovarian cancer xenograft models as well as a syngeneic ID8 tumor model, treatment with SGRMs demonstrated reduced levels of circulating MDSCs in the peripheral blood as well as tumor infiltrated MDSCs. Using neutralizing antibodies for cytokines, we will now identify key mechanisms, specifically, which targetable immunomodulatory factors are contributing to immune suppression. Based on the insight provided by these data, we propose to determine whether targeting ovarian tumor cell-intrinsic GR activation and resulting MDSC infiltration contributes to improved anti-tumor immune response. Presentation: Thursday, June 15, 2023

Relacorilant, a Selective Glucocorticoid Receptor Modulator in Development for the Treatment of Patients With Cushing Syndrome, Does Not Cause Prolongation of the Cardiac QT Interval

ObjectiveTo assess the effect of relacorilant, a selective glucocorticoid receptor modulator under investigation for the treatment of patients with endogenous hypercortisolism (Cushing syndrome [CS]), on the heart rate–corrected QT interval (QTc). MethodsThree clinical studies of relacorilant were included: (1) a first-in-human, randomized, placebo-controlled, ascending-dose (up to 500 mg of relacorilant) study in healthy volunteers; (2) a phase 1 placebo- and positive-controlled thorough QTc (TQT) study of 400 and 800 mg of relacorilant in healthy volunteers; and (3) a phase 2, open-label study of up to 400 mg of relacorilant administered daily for up to 16 weeks in patients with CS. Electrocardiogram recordings were taken, and QTc change from baseline (ΔQTc) was calculated. The association of plasma relacorilant concentration with the effect on QTc in healthy volunteers was assessed using linear mixed-effects modeling. ResultsAcross all studies, no notable changes in the electrocardiogram parameters were observed. At all time points and with all doses of relacorilant, including supratherapeutic doses, ΔQTc was small, generally negative, and, in the placebo-controlled studies, similar to placebo. In the TQT study, placebo-corrected ΔQTc with relacorilant was small and negative, whereas placebo-corrected ΔQTc with moxifloxacin positive control showed rapid QTc prolongation. These results constituted a negative TQT study. The model-estimated slopes of the concentration-QTc relationship were slightly negative, excluding an association of relacorilant with prolonged QTc. ConclusionAt all doses studied, relacorilant consistently demonstrated a lack of QTc prolongation in healthy volunteers and patients with CS, including in the TQT study. Ongoing phase 3 studies will help further establish the overall benefit-risk profile of relacorilant.

THU035 Impact Of Surgery Or Medical Treatment With The Selective Glucocorticoid Receptor Modulator Relacorilant On Hypercoagulopathy In Patients With Cushing Syndrome

Abstract Disclosure: C. Simeoli: None. N. Di Paola: None. A. Stigliano: None. P. Lardo: None. T. Kearney: Other; Self; Corcept Therapeutics. E. Mezosi: Grant Recipient; Self; Corcept Therapeutics. E. Ghigo: None. R. Giordano: None. C.N. Mariash: Grant Recipient; Self; Corcept Therapeutics. D. Donegan: Advisory Board Member; Self; Corcept Therapeutics. Other; Self; Corcept Therapeutics. R.A. Feelders: Consulting Fee; Self; Recordati. Grant Recipient; Self; Corcept Therapeutics. Speaker; Self; Recordati, HRA Pharma. A.L. Hand: Employee; Self; Corcept Therapeutics. A.G. Moraitis: Employee; Self; Corcept Therapeutics. R. Pivonello: Consulting Fee; Self; Corcept Therapeutics. Grant Recipient; Self; Corcept Therapeutics. In patients with Cushing syndrome (CS), hypercoagulability represents a significant concern, leading to an elevated risk for thrombotic events. Hypercoagulability persists for several months (mos) after curative surgery, and current CS treatment guidelines recommend anticoagulation therapy for up to 3 mos after surgery. In patients with Cushing disease, hemostatic parameters may even worsen after surgery, independent of surgical outcome, with improvements beginning about 3 mos after successful surgery (Casonato et al. Blood Coagul Fibrinolysis 1999). This transient worsening may be due to increased inflammation as cortisol levels, and hence cortisol’s anti-inflammatory effects, are reduced after successful surgery, leading to increased activity in the coagulation cascade, which normalizes over time. Here, we evaluate the impact of surgery or treatment with the selective glucocorticoid receptor modulator relacorilant (RELA) on the coagulation state in patients with CS, reporting findings from a retrospective, longitudinal, monocentric, surgical cohort study and an open-label phase 2 study of RELA (NCT02804750). In the surgical study, coagulation markers were assessed in 30 patients before curative surgery and in remission. In the RELA study, patients received either RELA 100-200 mg for 12 weeks or RELA 250-400 mg for 16 weeks; coagulation markers were assessed in 34 patients throughout the study. In the surgical study, baseline (BL) mean 24-h urinary free cortisol (UFC) was 615.6 mcg/day (by immunoassay; 2.1x upper limit of normal [ULN]); mean and median time to hemostasis assessment after remission were 6.2 and 6 mos, respectively. Significant mean changes from BL were observed in activated partial thromboplastin time (aPTT; +2.0 sec, P=0.031), factor VIII (fVIII; -24.2%, P=0.044), and von Willebrand factor (vWF; -20.6%, P=0.018), whereas platelet count was unchanged. In the RELA study, BL mean UFC was 211.9 mcg/day (by tandem mass spectrometry; 4.2x ULN). Similar to the surgical study, significant mean changes from BL to last observed visit were reported in aPTT (+1.5 sec, P=0.046), fVIII (-18.9%, P=0.022), and platelet count (-68.8*109/L, P&amp;lt;0.0001), while vWF was unchanged. Significant improvements in other coagulation factors, eg, fIX and fX, were seen in patients with abnormal values at BL. These studies showed that coagulation markers in patients with CS improve 6 mos after curative surgery, and that treatment with RELA may have similar effects after 3-4 mos. The previously observed transient increase in fVIII immediately after surgery was absent with RELA, where negative mean changes from BL were seen throughout the study. This is presumably due to the less abrupt reduction of cortisol activity with RELA compared to surgery. RELA’s effects on hypercoagulopathy support further investigation of preoperative use and in patients with CS who are not eligible for surgery. Presentation: Thursday, June 15, 2023

Withaferin A: A potential selective glucocorticoid receptor modulator with anti-inflammatory effect.

Glucocorticoids have been widely applied to various clinical treatment, however some serious side effects may occur during the treatment. It is widely known that glucocorticoids produce a marked effect through binding to glucocorticoid receptor (GR). As withaferin A can provide multiple health benefits, this work aims to confirm withaferin A as a potential selective GR modulator with anti-inflammatory effect. Fluorescence polarization assay confirmed that withaferin A could steadily bind to GR with an IC50 value of 203.80 ± 0.36 μM. Meanwhile, glucocorticoid receptor translocation of withaferin A was measured by nuclear fractionation assay. Dual luciferase reporter assay showed that withaferin A did not activate GR transcription. Furthermore, withaferin A decreased the GR-related protein expression with less side effects. The result of molecular docking showed that hydrogen-bonding and hydrophobic interactions contributed to the binding of withaferin A with GR. In addition, the GR-withaferin A complex maintained a stable binding throughout the dynamics simulation process. Enzyme-linked immunosorbent assay showed that withaferin A inhibited the production of cytokines, confirming its anti-inflammatory effect. These findings indicate that withaferin A is a potential selective GR modulator and this work may provide a research basis for developing dietary supplements and nutraceuticals against inflammation.