Selective Glucocorticoid Receptor Modulators Research Articles

The glucocorticoid receptor modulator relacorilant reverses the immunosuppressive effects of cortisol

Cortisol, an endogenous glucocorticoid receptor (GR) agonist, controls a broad transcriptional program that affects T-cell activation, pro-inflammatory cytokine secretion, apoptosis, and immune-cell trafficking. The degree to which endogenous cortisol blunts the anti-tumor immune response checkpoint inhibitors stimulate had not been assessed. We addressed this question using relacorilant, a selective GR modulator (SGRM) that competitively antagonizes the effects of cortisol activity. GR expression in human tumor and immune cells positively correlated with PD-L1 expression and tumor infiltration of Th2 and Treg cells, and negatively correlated with Th1-cell infiltration. In vitro, cortisol inhibited, and relacorilant restored, T-cell activation and pro-inflammatory cytokine secretion in human peripheral blood mononuclear cells. In the ovalbumin-expressing EG7 and MC38 immune-competent tumor models, relacorilant significantly improved anti-PD-1 antibody efficacy and showed favorable effects on antigen-specific T-cells and systemic TNFα and IL-10. These data characterize the broad immunosuppressive effects of endogenous cortisol and highlight the potential of combining an SGRM with an immune checkpoint inhibitor.

Impact of Surgery or Medical Treatment with the Selective Glucocorticoid Receptor Modulator Relacorilant on Hypercoagulopathy in Patients with Cushing Syndrome

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Abstract #1403093: Absence of QT Prolongation Associated with Relacorilant, a Selective Glucocorticoid Receptor Modulator in Development for the Treatment of Cushing Syndrome

QT prolongation is a significant concern for patients with Cushing syndrome (CS). Approximately 26% of men with CS present with QT prolongation, and the risk of cardiac arrhythmic events correlates with the extent of QT prolongation. All currently approved CS medications are associated with QT prolongation, posing a significant risk for the management of CS. Here, we evaluate the impact relacorilant, an investigational selective glucocorticoid receptor modulator, on QT prolongation in healthy volunteers and patients with CS. In a 3-part, single-center, first-in-human study (NCT03508635, “phase 1 study”), 103 healthy volunteers received single or multiple ascending doses of relacorilant (up to 500 mg QD) for up to 14 days; 24 received placebo. In a randomized, partial double-blind, crossover thorough QT study (NCT04795479, “TQT study”), the effect of multiple therapeutic (400 mg QD, n=25) and supra-therapeutic (800 mg QD, n=28) doses of relacorilant on cardiac repolarization was studied in healthy volunteers. A single dose of moxifloxacin (400 mg, n=28) was used as a positive control; 29 participants received placebo. In a single-arm, open-label phase 2 study (NCT02804750, “CS study”), 17 patients with CS received low-dose relacorilant (100–200 mg QD) for 12 weeks and 18 patients received high-dose relacorilant (250–400 mg QD) for 16 weeks. In all studies, ECG data were collected, and the heart rate-corrected QT interval using Fridericia’s formula (QTcF) was assessed. In the phase 1 study, relacorilant up to 500 mg daily did not adversely affect ECG parameters. An effect on placebo-corrected change from baseline QTcF (ΔΔQTcF) above 10 msec was excluded. In the TQT study, moxifloxacin control showed the expected QT prolongation, confirming assay sensitivity. Relacorilant had no adverse effects on ECG parameters and showed effects similar to placebo. Based on concentration-QTc analysis, an effect on ΔΔQTcF exceeding 10 msec was excluded within the full observed range of relacorilant plasma concentrations. These results constitute a negative TQT study. The CS study confirmed that these favorable findings also apply to patients with CS: Throughout the CS study, no significant changes in median QTcF were observed in either dose group. There is an unmet need for medications to treat CS that do not cause QT prolongation and possibly fatal arrhythmias. Based on the TQT study and supported by additional data in healthy volunteers and patients with CS, relacorilant did not show an association with QT prolongation.

Glucocorticoid Receptor and Ovarian Cancer: From Biology to Therapeutic Intervention

Ovarian cancer (OC) is the leading cause of death from gynecological malignancies worldwide. Fortunately, recent advances in OC biology and the discovery of novel therapeutic targets have led to the development of novel therapeutic agents that may improve the outcome of OC patients. The glucocorticoid receptor (GR) is a ligand-dependent transcriptional factor known for its role in body stress reactions, energy homeostasis and immune regulation. Notably, evidence suggests that GR may play a relevant role in tumor progression and may affect treatment response. In cell culture models, administration of low levels of glucocorticoids (GCs) suppresses OC growth and metastasis. Conversely, high GR expression has been associated with poor prognostic features and long-term outcomes in patients with OC. Moreover, both preclinical and clinical data have shown that GR activation impairs the effectiveness of chemotherapy by inducing the apoptotic pathways and cell differentiation. In this narrative review, we summarize data related to the function and role of GR in OC. To this aim, we reorganized the controversial and fragmented data regarding GR activity in OC and herein describe its potential use as a prognostic and predictive biomarker. Moreover, we explored the interplay between GR and BRCA expression and reviewed the latest therapeutic strategies such as non-selective GR antagonists and selective GR modulators to enhance chemotherapy sensitivity, and to finally provide new treatment options in OC patients.

Abstract 654: Ovarian cancer-cell glucocorticoid receptor activity modulates cytokine secretion promoting infiltration of immunosuppressive cells into the tumor microenvironment

Abstract Elevated levels of immunosuppressive myeloid-derived suppressor cells (MDSCs) circulate in the peripheral blood or infiltrate the tumors as well as 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 in part via modulating 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 upregulated secretion of immunomodulatory factors including G-CSF, TGFb and CXCL5. Moreover, co-treatment of cells with a selective GR modulator (SGRM), reverses this secretome effect. 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 tumor 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, identify 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. Citation Format: Manisha Taya, Eleanore LeBlanc, Lynda Bennett, Suzanne D. Conzen. Ovarian cancer-cell glucocorticoid receptor activity modulates cytokine secretion promoting infiltration of immunosuppressive cells into the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 654.

Abstract 3434: Selective glucocorticoid receptor modulation reveals a new role for CLEC10A in patients with solid tumors

Abstract Selective glucocorticoid receptor (GR) modulators (SGRMs) represent a clinically validated mechanism of enhancing chemosensitivity and ameliorating the sequelae of hypercortisolism. While GRs reportedly control the expression of up to 20% of the human genome, specific targets of systemic GR antagonism in humans have yet to be identified. To address this question, we established a robust NanoString assay to measure candidate GR target genes in human blood and assessed them before and after therapy with the oral SGRM relacorilant, which selectively antagonizes the GR. In a randomized, controlled phase 2 study in patients with recurrent, platinum-resistant ovarian cancer (NCT03776812), gene changes were assessed in 139 patients after treatment with relacorilant + nab-paclitaxel (NP) or NP alone. Using cross-validated random forest methods, a gene panel that accurately identified patients who had received relacorilant was established (ROC AUC 0.945 +/- 0.038). In 13 patients who crossed over from NP alone to relacorilant + NP, the genes in the panel were modified only after crossover (paired t-test P=0.0003), validating the gene panel’s ability to detect GR activity. The 4 most induced (LILRB4, FPR3, CLEC10A, CCR2) and 4 most suppressed (CDKN1C, TNFRSF17, BRIP1, PDK1) genes by relacorilant + NP vs. NP alone were selected and shown to be reliable indicators of GR activity across clinical studies in patients with pancreatic, prostate, and other solid tumors (NCT04329949, NCT03674814, NCT02762981), independent of concomitant medications or other confounders. CLEC10A (C-type lectin domain containing 10A) was identified as a particularly sensitive marker of GR activity as its expression was strongly suppressed by the GR agonist prednisone in healthy volunteers (paired t-test P<0.00010, NCT03335956) and strongly induced by relacorilant in patients with solid tumors (paired t-test P<0.00010). CLEC10A induction in blood by relacorilant was associated with longer overall survival in patients with ovarian cancer treated with relacorilant + NP (HR=0.39, Cox PH P=0.0135). High baseline tumor CLEC10A expression was also associated with longer overall survival in a large tumor ‘omics’ database (N=1656 ovarian tumors; HR 0.8, log-rank P=0.0008). CLEC10A and the genes correlated with its expression were found to be primarily expressed by a specific subset of dendritic cells, supporting previous reports that GR agonism can suppress dendritic cells. This analysis of CLEC10A and other identified GR target genes confirmed that systemic GR activity in patients with a range of solid tumors can be modulated pharmacologically, indicates that GR modulation may be associated with survival in patients with ovarian cancer, and provides new insights into the systemic functions of the GR in humans. Citation Format: Nicoletta Colombo, Toon Van Gorp, Ursula A. Matulonis, Ana Oaknin, Rachel N. Grisham, Diane Provencher, Gini F. Fleming, Alexander B. Olawaiye, Erkut H. Borazanci, Russell Z. Szmulewitz, Subhagya A. Wadekar, Grace Mann, Hazel J. Hunt, Andrew E. Greenstein, Domenica Lorusso. Selective glucocorticoid receptor modulation reveals a new role for CLEC10A in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3434.

Abstract P2-20-01: Patient-derived triple-negative breast cancer organoids as a platform for glucocorticoid receptor- mediated mechanisms of immunotherapy response and resistance

Abstract Background: In early-stage triple-negative breast cancer (TNBC), high glucocorticoid receptor (GR) expression correlates with worse relapse-free survival across TNBC subtypes, induces oncogenic gene expression and tumor cell survival, and potentiates anti-inflammatory or an anti-immunogenic phenotype. Immune checkpoint therapy has increased pathologic complete response rates in the neoadjuvant setting, however response to immunotherapy remains modest overall and the explanatory mechanisms for this phenomenon are incompletely understood. We sought a three-dimensional model of the TNBC immune microenvironment using patient-derived organoids (PDOs) that capture tumor heterogeneity, partially recapitulates tumor microenvironment, and can be established for longer-term in vitro/in-vivo translational study after exposure to immunotherapy. We hypothesize that during chemoimmunotherapy treatment of early-stage triple-negative breast cancer, high glucocorticoid receptor activity mediates an immunosuppressive phenotype and glucocorticoid receptor modulation can restore anti-tumor immunity. Methods and Results: We are successfully growing 5 PDOs out of 8 surgically resectedion samples tumors from patients with early-stage triple-negative breast cancer treated with chemotherapy vs. chemoimmunotherapy as per KEYNOTE-522. Interrogation of complementary TNBC cell line data revealed that GR activation downregulates the expression of immune checkpoint genes (PD-L1, B7-H3, B7-H4), while GR knockdown or treatment with a selective GR modulator restores expression of these immune checkpoint genes. TNBC-intrinsic GR activation increases the proportion of regulatory T cells vs. CD8+ T cells. In a coculture system of TNBC spheroids and T cells, GR activation in TNBC results in decreased activated CD8+ CD137+ T cells and use of the selective GR modulator increases the proportion of activated CD8+ CD137+ T cells. Conclusions and Future Directions: In early-stage triple-negative breast cancer, GR activation downregulates expression of immune checkpoint genes and reduction of GR activity restores expression. In a coculture system that recapitulates T cell repertoire found in triple-negative breast cancer, tumor-intrinsic GR activation results in increased regulatory T cell population and reduction of GR activity increases activated CD8+ CD137+ T cells. Ongoing analyses of TNBC organoid-immune coculture systems modeling high GR states will be used to (i) define cooperativity amongst immune checkpoint proteins in costimulation vs. coinhibition of anti-tumor responses and (ii) define novel pairs of receptor-ligands amongst TNBC:CD8+ vs. TNBC:Treg vs. CD8+:Treg as discovery of potential new therapeutic targets. Citation Format: Christine Shiang, Candace Frerich, Ishrat Durdana, Cheryl Lewis, Lynda B. Bennett, Carlos Arteaga, Suzanne D. Conzen. Patient-derived triple-negative breast cancer organoids as a platform for glucocorticoid receptor- mediated mechanisms of immunotherapy response and resistance [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-20-01.

Phase 1 efficacy and pharmacodynamic results of exicorilant + enzalutamide in patients with metastatic castration-resistant prostate cancer.

145 Background: Metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease with significant morbidity. Androgen receptor (AR) signaling is a key driver of tumor growth in mCRPC, and AR-targeted therapies are the mainstay for patients (pts) with locally advanced or metastatic disease. Enzalutamide (ENZA) is commonly used, but resistance typically develops within 1–2 years. The glucocorticoid receptor (GR) can substitute for the AR, providing a tumor escape pathway (Arora et al. Cell 2013). In the 22Rv1 CRPC xenograft model, the selective GR modulator exicorilant (EXI) combined with ENZA reduced tumor growth, supporting the hypothesis that dual antagonism of GR + AR may block this escape pathway. Safety and pharmacokinetics from the first study of EXI + ENZA in pts with mCRPC (NCT03437941) were previously presented (Linch et al. ESMO 2022). Here, we report efficacy and pharmacodynamic (PD) results from the same study. Methods: Segment 1 (Seg 1) of this phase 1 study evaluated open-label, fasting, BID dosing of EXI (140 or 180 mg) + ENZA 160 mg QD. Segment 2 (Seg 2) tested QD dosing of EXI with food in a double-blind design: All pts received EXI 240 mg + ENZA and were randomized 3:1 to EXI titration (to 280 mg followed by 320 mg) or to remain on EXI 240 mg + placebo. Efficacy assessments included radiographic response and changes in prostate-specific antigen (PSA) levels. PSA was collected prior to study entry and PSA doubling times were calculated before and during treatment. PD analyses included baseline (BL) tumor GR expression and modulation of GR target genes in whole blood. As not all pts enrolled in Seg 1 were ENZA naïve, efficacy data are reported for Seg 2 only. Data cutoff date: July 7, 2022. Results: 39 pts were enrolled (Seg 1: 14, irrespective of prior ENZA exposure; Seg 2: 25, on a stable ENZA dose with rising PSA, defined as a 25% increase over nadir and absolute value >1 ng/mL). In Seg 2, there were no radiographic responses, 18 pts had a best overall response of stable disease per PCWG3, and 1 pt achieved a PSA response (≥50% PSA reduction from BL). BL tumor GR expression was detectable in all assessed tumors. PD analyses demonstrated EXI modulation of GR target genes, such as CDKN1C. Comparable PD effects were observed across EXI doses (240–320 mg QD). While BL 24-h urinary free cortisol (UFC) for most pts was within the normal range, improvements in PSA doubling times after treatment with EXI + ENZA were predominantly observed in pts with higher BL UFC ( P<0.05). Conclusions: This study did not include an ENZA-alone arm and was thus not designed to assess the contribution of EXI to the efficacy of the EXI + ENZA combination. In heavily pretreated pts with prior ENZA exposure, 1 PSA response and no radiographic responses were observed. PD analysis confirmed systemic GR modulation. Instances of PSA doubling time improvements were observed in pts with relatively higher UFC. Clinical trial information: NCT03437941 .

Genetically engineered human pituitary corticotroph tumor organoids exhibit divergent responses to glucocorticoid receptor modulators

Cushing's disease (CD) is a serious endocrine disorder attributed to an adrenocorticotropic hormone (ACTH)-secreting pituitary neuroendocrine tumor (PitNET) that that subsequently leads to chronic hypercortisolemia. PitNET regression has been reported following treatment with the investigational selective glucocorticoid receptor (GR) modulator relacorilant, but the mechanisms behind that effect remain unknown. Human PitNET organoid models were generated from induced human pluripotent stem cells (iPSCs) or fresh tissue obtained from CD patient PitNETs (hPITOs). Genetically engineered iPSC derived organoids were used to model the development of corticotroph PitNETs expressing USP48 (iPSCUSP48) or USP8 (iPSCUSP8) somatic mutations. Organoids were treated with the GR antagonist mifepristone or the GR modulator relacorilant with or without somatostatin receptor (SSTR) agonists pasireotide or octreotide. In iPSCUSP48 and iPSCUSP8 cultures, mifepristone induced a predominant expression of SSTR2 with a concomitant increase in ACTH secretion and tumor cell proliferation. Relacorilant predominantly induced SSTR5 expression and tumor cell apoptosis with minimal ACTH induction. Hedgehog signaling mediated the induction of SSTR2 and SSTR5 in response to mifepristone and relacorilant. Relacorilant sensitized PitNET organoid responsiveness to pasireotide. Therefore, our study identified the potential therapeutic use of relacorilant in combination with somatostatin analogs and demonstrated the advantages of relacorilant over mifepristone, supporting its further development for use in the treatment of Cushing's disease patients.

Discovery and Optimization of N-Acyl-6-sulfonamide-tetrahydroquinoline Derivatives as Novel Non-Steroidal Selective Glucocorticoid Receptor Modulators.

Selective glucocorticoid receptor modulators (SGRMs), which can dissociate the transactivation from the transrepression of the glucocorticoid receptor (GR), are regarded as very promising therapeutics for inflammatory and autoimmune diseases. We previously discovered a SGRM HP-19 based on the passive antagonistic conformation of GR and bioassays. In this study, we further analyzed the dynamic changes of the passive antagonistic state upon the binding of HP-19 and designed and synthesized 62 N-acyl-6-sulfonamide-tetrahydroquinoline derivatives by structural optimization of HP-19. Therein, compound B53 exhibits the best transrepression activity (IC50 NF-κB = 0.009 ± 0.001 μM) comparable with dexamethasone (IC50 NF-κB = 0.005 ± 0.001 μM) and no transactivation activity. B53 can efficiently reduce the expression of inflammatory factors IL-6, IL-1β, TNF-α, and so on and makes a milder adverse effect and is highly specific to GR. Furthermore, B53 is able to significantly relieve dermatitis on a mouse model via oral drug intervention.

610 Identification of the selective glucocorticoid receptor agonist Mapracorat as potential new drug for chronic wound therapy

We have shown that the effects of wound exudates on fibroblast cultures reflect their clinical healing phenotype and can thus serve as a functional biomarker. We used this assay for screening to identify compounds or compound classes with so far unknown potential for chronic wound therapy. The selective glucocorticoid receptor agonist (SEGRA) Mapracorat was found to reverse the inhibitory effect of several exudates. The compound was profiled in additional exudate-based cellular assays to investigate its suitability for wound therapy. Primary human dermal fibroblasts were grown in 384-well plates in 2D and 3D cultures. Mapracorat was added to the cells in the presence of wound exudates from different chronic wound patients. Incubation times were 72 hours for 2D cultures and 4 – 8 days for 3D cultures. Supernatants were then harvested for the determination of IL-1beta, RNA was extracted for RT-PCR, or cells were fixed and stained for cellular protein. Mapracorat rescued inhibition of wound exudate-induced fibroblast proliferation in 80% of 200 exudates tested. For 95/200 exudates from chronic wounds of different etiologies, cell proliferation was increased by Mapracorat by >150% compared to exudate alone, and complete recovery was demonstrated in 25% of these samples. This rescue effect was achieved at low nanomolar concentrations. The compound dose-dependently inhibited IL-1beta production and enhanced matrix formation as well as collagen 1 and collagen 3 mRNA expression, indicating transition from a chronic/non-healing to a healing phenotype ex vivo. In functional ex vivo assays for chronic wounds, Mapracorat reversed the detrimental effects of wound exudates on fibroblast proliferation and matrix formation, and reduced proinflammatory cytokine secretion. Mapracorat showed good or excellent activity with almost 50% of exudates. To select the patients best suited for therapy with this compound, theranostic pretesting is recommended.

PMON165 Favorable Liver Safety Profile of the Selective Glucocorticoid Receptor Modulator Relacorilant in Healthy and Hepatically Impaired Adults and in Patients with Cushing Syndrome

Abstract Background Relacorilant is a highly selective glucocorticoid receptor (GR) modulator in development for the treatment of endogenous Cushing syndrome (CS). Unlike the FDA-approved GR antagonist mifepristone, relacorilant lacks affinity for the progesterone and other receptors. In a phase 2 study in patients with CS (NCT02804750, Pivonello et al, 2021), relacorilant provided clinically meaningful changes in a number of cortisol-excess-related comorbidities, including hypertension and hyperglycemia, without undesirable antiprogesterone effects or drug-induced hypokalemia. Currently, 4 clinical studies of relacorilant in patients with CS are ongoing: GRACE (NCT03697109), a phase 3 trial enrolling patients with endogenous CS of all etiologies; GRADIENT (NCT04308590), a phase 3 trial focusing on hypercortisolism due to adrenal adenomas or hyperplasia; a phase 2/3 long-term extension study (NCT03604198); and a phase 1b study in patients with adrenocortical carcinoma associated with glucocorticoid excess (NCT04373265). Here, we report safety results and liver function test (LFT) changes from open-label phase 1 and 2 studies of relacorilant in healthy and hepatically impaired adults and in adult patients with CS. Methods In a special population study, 9 subjects with moderate hepatic impairment (Child-Pugh Class B) and 9 matched controls with normal hepatic function received relacorilant (300 mg QD) for 10 days. In a phase 1 fixed-sequence drug-drug interaction study (NCT03512548), 28 healthy subjects received relacorilant (300 mg QD) for 10 days followed by 10 days of relacorilant (300 mg QD) combined with itraconazole (200 mg QD). Thirty-five patients with CS received relacorilant (100–400 mg QD) for up to 16 weeks in the phase 2 study. Results While relacorilant is eliminated primarily through the hepatic route, no apparent difference in relacorilant pharmacokinetics in subjects with moderate hepatic impairment vs matched controls was observed, with relacorilant exposures (as measured by area under the concentration-time curve [AUC] and maximum concentration [Cmax]) largely overlapping across both groups. In addition, reductions in LFTs were observed in this study. In healthy adults treated with relacorilant followed by relacorilant + itraconazole (an agent with reported liver toxicity), a similar trend toward reduced LFTs was seen throughout the study. In the phase 2 study in patients with CS, reductions in LFTs were also observed, including normalization of LFTs in some patients with abnormal values at baseline. Conclusions These results suggest that relacorilant has a favorable liver safety profile that includes a trend toward improved LFTs in volunteers and patients with normal and abnormal liver function. The findings of the hepatic impairment study support the use of relacorilant without dose adjustment in patients with moderate hepatic impairment. Presentation: Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

OR22-6 Ovarian Cancer Cell Glucocorticoid Receptor Activity Is Associated With Cytokine Secretion Promoting Infiltration of Immunosuppressive Cells Into the Tumor Microenvironment

Abstract Immunosuppressive cells abundantly infiltrate tumors during cancer progression. Notably, immunosuppressive myeloid-derived suppressor cells (MDSCs) have recently been identified as a heterogeneous cell population that expand during tumor-associated inflammation and are significantly increased in the tumor, peripheral blood, as well as ascites of ovarian cancer patients. MDSCs contribute to tumor immune tolerance via inhibition of T-cell proliferation and activation. Signals from the tumor microenvironment in the form of soluble cytokines are proposed to lead to MDSC infiltration. It is also known that high tumor cell glucocorticoid receptor (GR) expression is associated with a relatively poor prognosis in ovarian cancer patients. We hypothesized that ovarian cancer cell GR expression and activity may modulate tumor cell cytokine secretion thereby leading to increased MDSC generation and recruitment to the tumor, thereby creating an immunosuppressive environment. Our preliminary data confirm that GR activation in two high-grade ovarian cancer cell lines (HeyA8 and SKOV3) modulates the cytokine secretome. Our results demonstrate GR-mediated secretion of several pro-tumorigenic and immunosuppressive proteins including G-CSF, M-CSF, TGF-b, and MCP-1 in those ovarian cancer models. We also observed downregulation of potent cytotoxic T-cell activating cytokines required for anti-tumor T-cell function including IL-2, IFN-g and MIP1 upon GR activation. Importantly, treatment of cells with a selective GR modulator (SGRM) reverses this immunosuppressive secretome effect. Furthermore, upon culturing healthy peripheral blood mononuclear cells (PBMCs) with tumor conditioned media from GR activated ovarian cancer cells, we show that secreted immunomodulatory factors have the capacity to promote differentiation of human MDSCs from progenitor myeloid cells. The resulting MDSC population was characterized via expression of activation markers including Arginase-1, iNOS, VEGF and TGF-b. Most importantly, the suppressive function of these MDSCs is being evaluated by determining their inhibitory potential on cytotoxic T-cell proliferation and/or activation. Based on the insight provided by these data, we propose to determine whether ovarian tumor cell-intrinsic GR activation and resulting MDSC generation contributes to earlier relapse of GR-positive ovarian cancers, and eventually whether this mechanism may be targeted to improve patient outcomes in this subset of ovarian cancers. Presentation: Monday, June 13, 2022 12:15 p.m. - 12:30 p.m.

RF15 | PMON294 Disrupting a Key H-bond Network Drives Glucocorticoid Receptor Gene Suppression Without Off-target Gene Activation for Duchenne Muscular Dystrophy Treatment

Abstract Duchenne muscular dystrophy is a genetic disorder that shows chronic and progressive damage to skeletal and cardiac muscle leading to premature death. Anti-inflammatory corticosteroids targeting the glucocorticoid receptor (GR) are the current standard of care but drive adverse side effects such as deleterious bone loss. Through subtle modification to a steroidal backbone, a recently developed drug, vamorolone, appears to preserve beneficial efficacy but with significantly reduced side effects. We use combined structural, biophysical, and biochemical approaches to show that loss of a receptor-ligand hydrogen bond drives these remarkable therapeutic effects. Moreover, vamorolone uniformly weakens coactivator associations but not corepressor associations, implicating partial agonism as the main driver of its dissociative properties. Additionally, we identify a critical and evolutionarily conserved intramolecular network connecting the ligand to the coregulator binding surface. Interruption of this allosteric network by vamorolone selectively reduces GR-driven transactivation while leaving transrepression intact. Our results establish a mechanistic understanding of how vamorolone reduces side effects, guiding the future design of partial agonists as selective GR modulators with an improved therapeutic index. Presentation: Sunday, June 12, 2022 1:00 p.m. - 1:05 p.m., Monday, June 13, 2022 12:30 p.m. - 2:30 p.m.

Structure-based virtual screening, molecular docking, molecular dynamics simulation and MM/PBSA calculations towards identification of steroidal and non-steroidal selective glucocorticoid receptor modulators

Glucocorticoids have been used in the treatment of many diseases including inflammatory and autoimmune diseases. Despite the wide therapeutic effects of synthetic glucocorticoids, the use of these compounds has been limited due to side effects such as osteoporosis, immunodeficiency, and hyperglycaemia. To this end, extensive studies have been performed to discover new glucocorticoid modulators with the aim of increasing affinity for the receptor and thus less side effects. In the present work, structure-based virtual screening was used for the identification of novel potent compounds with glucocorticoid effects. The molecules derived from ZINC database were screened on account of structural similarity with some glucocorticoid agonists as the template. Subsequently, molecular docking was performed on 200 selected compounds to obtain the best steroidal and non-steroidal conformations. Three compounds, namely ZINC_000002083318, ZINC_000253697499 and ZINC_000003845653, were selected with the binding energies of −11.5, −10.5, and −9.5 kcal/mol, respectively. Molecular dynamic simulations on superior structures were accomplished with the glucocorticoid receptor. Additionally, root mean square deviations, root mean square fluctuation, radius of gyration, hydrogen bonds, and binding-free energy analysis showed the binding stability of the proposed compounds compared to budesonide as an approved drug. The results demonstrated that all the compounds had suitable binding stability compared to budesonide, while ZINC_000002083318 showed a tighter binding energy compared to the other compounds. Communicated by Ramaswamy H. Sarma

524MO Glucocorticoid receptor expression and activity in a phase II ovarian cancer trial of the glucocorticoid receptor modulator relacorilant in combination with nab-paclitaxel

Cortisol activity at the glucocorticoid receptor (GR) contributes to chemotherapy resistance by suppressing apoptotic pathways that taxanes utilize, and high tumor GR expression is associated with poor chemotherapy response in ovarian cancer. A phase 2 ovarian cancer study (NCT03776812) demonstrated the clinical benefit of adding relacorilant (RELA), a selective GR modulator, to nab-paclitaxel (NP) compared to NP alone. We present biomarker analyses from this study.

1397P Phase I results of exicorilant plus enzalutamide in patients with castration-resistant prostate cancer

Metastatic castration-resistant prostate cancer (mCRPC) remains an incurable disease with significant morbidity, despite the availability of multiple classes of therapies. Combining the selective glucocorticoid receptor (GR) modulator exicorilant (EXI) with the androgen receptor (AR) antagonist enzalutamide (ENZA) may block an important tumor escape pathway via dual antagonism of GR and AR. We report safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) results from the first study evaluating EXI + ENZA in patients with CRPC. Segment 1 of this phase 1/2a dose-finding study (NCT03437941) evaluated open-label, twice-daily dosing of EXI. Patients (irrespective of prior ENZA exposure) received either EXI 180 mg BID + ENZA 160 mg QD, EXI 140 mg BID + ENZA 160 mg QD with a 28-day ENZA lead-in, or EXI 140 mg BID + ENZA 160 mg QD without an ENZA lead-in. Segment 2 evaluated QD dosing of EXI in a double-blind design in patients on a stable ENZA dose with rising PSA (25% increase over nadir and absolute value >1 ng/mL). All patients received EXI 240 mg QD + ENZA and were randomized 3:1 to EXI titration (to 280 mg followed by 320 mg) or to stay on EXI 240 mg. PK (EXI, ENZA) and PD (including cortisol and ACTH) were measured throughout the study. 14 and 25 patients were enrolled in segments 1 and 2, respectively. 37 patients received at least one dose of EXI. Most frequent EXI-related adverse events (AEs) included fatigue (57%), back pain (35%), decreased appetite (27%), and neuropathic pain (22%). Dose-limiting toxicities were fatigue, musculoskeletal pain, and pancreatitis in segment 1, and fatigue, lipase increase, hypophosphatemia, AST/ALT/GGT increase, back pain, and vomiting in segment 2. EXI exposures were largely overlapping across dose levels in segment 2. No clinically relevant changes in the exposures of ENZA or its active metabolite, N-desmethyl ENZA, were observed when combined with EXI. ENZA exposures were consistent with historical data for ENZA 160 mg alone. A maximum-tolerated dose of EXI in combination with ENZA was identified with fatigue and pain as the most common AEs. No clinically relevant changes were observed in ENZA exposure when given with EXI relative to ENZA alone.

Selected Articles from This Issue

Highlights| August 02 2022 Selected Articles from This Issue Author & Article Information Online ISSN: 1557-3265 Print ISSN: 1078-0432 ©2022 American Association for Cancer Research2022American Association for Cancer Research Clin Cancer Res (2022) 28 (15): 3171. https://doi.org/10.1158/1078-0432.CCR-28-15-HI Related Content A commentary has been published: Activity of Adagrasib (MRTX849) in Brain Metastases: Preclinical Models and Clinical Data from Patients with KRASG12C-Mutant Non–Small Cell Lung Cancer A commentary has been published: Neoadjuvant Chemoimmunotherapy for the Treatment of Locally Advanced Head and Neck Squamous Cell Carcinoma: A Single-Arm Phase 2 Clinical Trial A commentary has been published: Phase II Clinical Trial of Eribulin–Gemcitabine Combination Therapy in Previously Treated Patients With Advanced Liposarcoma or Leiomyosarcoma View more A commentary has been published: Overcoming Taxane Resistance: Preclinical and Phase 1 Studies of Relacorilant, a Selective Glucocorticoid Receptor Modulator, with Nab-Paclitaxel in Solid Tumors View less Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Article Versions Icon Versions Version of Record August 2 2022 Citation Selected Articles from This Issue. Clin Cancer Res 1 August 2022; 28 (15): 3171. https://doi.org/10.1158/1078-0432.CCR-28-15-HI Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search Advanced Search Effective systemic treatment options are largely limited for previously treated liposarcoma and leiomyosarcoma. In this phase II study, Kim and colleagues show that eribulin–gemcitabine combination therapy demonstrated appreciable efficacy compared to monotherapy from the historic arm. Functional enrichment in the transforming growth factor-ß pathway would hold predictive value for the survival outcomes of the combination therapy, although further confirmatory investigation may be required. Eribulin–gemcitabine combination therapy could present as a future treatment option for refractory soft tissue sarcomas with liposarcoma or leiomyosarcoma histology. Chemotherapy resistance remains a key challenge in the treatment of solid tumors. Cortisol can facilitate resistance by suppressing apoptotic pathways that cytotoxic agents utilize. Munster and colleagues studied the ability of relacorilant, a selective glucocorticoid receptor modulator, to restore chemosensitivity and enhance chemotherapy efficacy by reversing cortisol’s antiapoptotic effects. In preclinical studies, relacorilant enhanced chemotherapy efficacy. A phase I study showed durable disease control with relacorilant +... You do not currently have access to this content.

Novel assays monitoring direct glucocorticoid receptor protein activity exhibit high predictive power for ligand activity on endogenous gene targets.

Exogenous glucocorticoids are widely used in the clinic for the treatment of inflammatory disorders and auto-immune diseases. Unfortunately, their use is hampered by many side effects and therapy resistance. Efforts to find more selective glucocorticoid receptor (GR) agonists and modulators (called SEGRAMs) that are able to separate anti-inflammatory effects via gene repression from metabolic effects via gene activation, have been unsuccessful so far. In this study, we characterized a set of functionally diverse GR ligands in A549 cells, first using a panel of luciferase-based reporter gene assays evaluating GR-driven gene activation and gene repression. We expanded this minimal assay set with novel luciferase-based read-outs monitoring GR protein levels, GR dimerization and GR Serine 211 (Ser211) phosphorylation status and compared their outcomes with compound effects on the mRNA levels of known GR target genes in A549 cells and primary hepatocytes. We found that luciferase reporters evaluating GR-driven gene activation and gene repression were not always reliable predictors for effects on endogenous target genes. Remarkably, our novel assay monitoring GR Ser211 phosphorylation levels proved to be the most reliable predictor for compound effects on almost all tested endogenous GR targets, both driven by gene activation and repression. The integration of this novel assay in existing screening platforms running both in academia and industry may therefore boost chances to find novel GR ligands with an actual improved therapeutic benefit.

Application of a pharmacological transcriptome filter identifies a shortlist of mouse glucocorticoid receptor target genes associated with memory consolidation

Glucocorticoids regulate memory consolidation, facilitating long-term storage of relevant information to adequately respond to future stressors in similar conditions. This effect of glucocorticoids is well-established and is observed in multiple types of behaviour that depend on various brain regions. By and large, higher glucocorticoid levels strengthen event-related memory, while inhibition of glucocorticoid signalling impairs consolidation. The mechanism underlying this glucocorticoid effect remains unclear, but it likely involves the transcriptional effects of the glucocorticoid receptor (GR). We here used a powerful paradigm to investigate the transcriptional effects of GR in the dorsal hippocampus of mice after training in an auditory fear conditioning task, aiming to identify a shortlist of GR target genes associated to memory consolidation. Therefore, we utilized in an explorative study the properties of selective GR modulators (CORT108297 and CORT118335), alongside the endogenous agonist corticosterone and the classical GR antagonist RU486, to pinpoint GR-dependent transcriptional changes. First, we confirmed that glucocorticoids can modulate memory strength via GR activation. Subsequently, by assessing the specific effects of the available GR-ligands on memory strength, we established a pharmacological filter which we imposed on the hippocampal transcriptome data. This identified a manageable shortlist of eight genes by which glucocorticoids may modulate memory consolidation, warranting in-depth follow-up. Overall, we showcase the strength of the concept of pharmacological transcriptome filtering, which can be readily applied to other research topics with an established role of glucocorticoids.