A new therapeutic approach in the medical treatment of Cushing's syndrome: glucocorticoid receptor blockade with mifepristone

Treatment of Cushing's syndrome with osilodrostat: practical applications of recent studies with case examples

Endogenous Cushing's syndrome (CS) is a rare endocrine condition frequently caused by a tumor resulting in elevated cortisol levels. Cushing's disease (CD) caused by an adrenocorticotropic hormone-secreting pituitary adenoma is the most common form of endogenous CS. Medical therapy for CD is mostly used as second-line treatment after failed surgery or recurrence and comprises several pituitary-directed drugs, adrenal steroidogenesis inhibitors, and a glucocorticoid receptor blocker, some of which are US Food and Drug Administration (FDA)-approved for this condition. The recent Pituitary Society consensus guidelines for diagnosis and management of CD described osilodrostat, an oral inhibitor of 11β-hydroxylase, as an effective, FDA-approved medical therapy for CD. Because clinical experience outside clinical trials is limited, we provide here a review of published data about osilodrostat and offer example case studies demonstrating practical considerations on the use of this medication. Recommendations regarding osilodrostat are provided for the following situations: specific assessments needed before treatment initiation; monitoring for adrenal insufficiency, hypokalemia, and changes in QTc; the potential value of a slow up-titration in patients with mild disease; managing temporary treatment cessation for patients with CD who have acquired coronavirus disease 2019; monitoring for increased testosterone levels in women; exercising caution with concomitant medication use; considering whether a higher dose at nighttime might be beneficial; and managing cortisol excess in ectopic and adrenal CS. This review highlights key clinical situations that physicians may encounter when using osilodrostat and provides practical recommendations for optimal patient care when treating CS, with a focus on CD.

Glucocorticoid receptor blockers

Mifepristone is the only glucocorticoid receptor antagonist currently approved for the treatment of Cushing's syndrome. Although originally developed as an abortifacient due to its blockade of the progesterone receptor, a number of case reports documented its efficacy as a glucocorticoid receptor blocker going back to 1985. The SEISMIC trial, published in 2012, provided sufficient data on efficacy and adverse effects for regulatory approval. Mifepristone provides clear benefits on glycemia, blood pressure, muscle weakness, body weight and the other myriad clinical manifestations of Cushing's syndrome. However, because it blocks the glucocorticoid receptor, blood cortisol and ACTH levels actually rise, rather than fall; this complicates patient management. Doses are adjusted based on clinical manifestations rather than hormone levels. Adverse effects include adrenal insufficiency due to overdosage, hypokalemia, and menorrhagia. Treatment of severe adrenal insufficiency requires high doses of dexamethasone. Other glucocorticoid receptor blockers without effects on the progesterone receptor are being developed. Because mifepristone inhibits CYP3A and CYP2C8/2C9, drug-drug interactions can occur. These potential adverse effects can largely be avoided with careful attention to detail. My opinion is that its current place in therapy is in patients with severe disease and in those not responding to other treatments.

Past, Present, and Future of Therapies for Pituitary Neuroendocrine Tumors: Need for Omics and Drug Repositioning Guidance

Innovation roadmaps are important, because they encourage the actors in an innovation ecosystem to creatively imagine multiple possible science future(s), while anticipating the prospects and challenges on the innovation trajectory. In this overarching context, this expert review highlights the present unmet need for therapeutic innovations for pituitary neuroendocrine tumors (PitNETs), also known as pituitary adenomas. Although there are many drugs used in practice to treat PitNETs, many of these drugs can have negative side effects and show highly variable outcomes in terms of overall recovery. Building innovation roadmaps for PitNETs' treatments can allow incorporation of systems biology approaches to bring about insights at multiple levels of cell biology, from genes to proteins to metabolites. Using the systems biology techniques, it will then be possible to offer potential therapeutic strategies for the convergence of preventive approaches and patient-centered disease treatment. Here, we first provide a comprehensive overview of the molecular subtypes of PitNETs and therapeutics for these tumors from the past to the present. We then discuss examples of clinical trials and drug repositioning studies and how multi-omics studies can help in discovery and rational development of new therapeutics for PitNETs. Finally, this expert review offers new public health and personalized medicine approaches on cases that are refractory to conventional treatment or recur despite currently used surgical and/or drug therapy.

Perioperative Management of a Patient with Cushing’s Disease

Patients with Cushing’s disease (CD) may present with both chronic and acute perioperative complications that necessitate multidisciplinary care. This review highlights several objectives for these patients before and after transsphenoidal surgery. Preoperative management includes treatment of electrolyte disturbances, cardiovascular comorbidities, prediabetes/diabetes, as well as prophylactic consideration(s) for thromboembolism and infection(s). Preoperative medical therapy (PMT) could prove beneficial in patients with severe hypercortisolism or in cases of delayed surgery. Some centers use PMT routinely, although the clinical benefit for all patients is controversial. In this setting, steroidogenesis inhibitors are preferred because of rapid and potent inhibition of cortisol secretion. If glucocorticoids are not used perioperatively, an immediate remission assessment postoperatively is possible. However, perioperative glucocorticoid replacement is sometimes necessary for clinically unstable or medically pretreated patients and for those patients with surgical complications. A nadir serum cortisol < 2-5µg/dl during 24-74 hours postoperatively is generally accepted as remission; higher values suggest non-remission, while a few patients may display delayed remission. If remission is not achieved, additional treatments are pursued. The early postoperative period necessitates multidisciplinary awareness for early diagnosis of adrenal insufficiency (AI) to avoid adrenal crisis, which may be also potentiated by acute postoperative complications. Preferred glucocorticoid replacement is hydrocortisone, if available. Assessment of recovery from postoperative AI should be undertaken periodically. Other postoperative targets include decreasing antihypertensive/diabetic therapy if in remission, thromboprophylaxis, infection prevention/treatment, and management of electrolyte disturbances and/or potential pituitary deficiencies. Evaluation of recovery of thyroid, gonadal and growth hormone deficiencies should be also performed in the following months postoperatively.

Consensus on diagnosis and management of Cushing's disease: a guideline update

Cushing's disease requires accurate diagnosis, careful treatment selection, and long-term management to optimise patient outcomes. The Pituitary Society convened a consensus workshop comprising more than 50 academic researchers and clinical experts to discuss the application of recent evidence to clinical practice. In advance of the virtual meeting, data from 2015 to present about screening and diagnosis; surgery, medical, and radiation therapy; and disease-related and treatment-related complications of Cushing's disease summarised in recorded lectures were reviewed by all participants. During the meeting, concise summaries of the recorded lectures were presented, followed by small group breakout discussions. Consensus opinions from each group were collated into a draft document, which was reviewed and approved by all participants. Recommendations regarding use of laboratory tests, imaging, and treatment options are presented, along with algorithms for diagnosis of Cushing's syndrome and management of Cushing's disease. Topics considered most important to address in future research are also identified.

Clinical management of patients with Cushing syndrome treated with mifepristone: consensus recommendations

BACKGROUND

While surgery is the first-line treatment for patients with endogenous hypercortisolism (Cushing syndrome [CS]), mifepristone has been shown to be a beneficial medical treatment option, as demonstrated in the SEISMIC (Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing Syndrome) trial. Mifepristone is a competitive glucocorticoid receptor antagonist and progesterone receptor antagonist that is associated with several treatment effects and adverse events that clinicians need to be aware of when considering its use. The objective of this review was to provide updated clinical management recommendations for patients with CS treated with mifepristone.

METHODS

A panel of endocrinologists from the US with extensive experience in treating patients with CS, including with mifepristone, convened as part of a clinical advisory board to develop a consensus on the practical, real-world clinical management of patients on mifepristone.

RESULTS

Comprehensive considerations and recommendations are provided for managing mifepristone-associated effects, including symptoms of cortisol withdrawal, hypokalemia, and change in thyroid function; effects related to its antiprogesterone activity; and rash. Additional management strategies to address concomitant medications and special clinical situations, such as surgery and use in specific populations, are also provided.

CONCLUSION

Safe and effective use of mifepristone requires clinical judgment and close patient monitoring to ensure optimal clinical outcomes. These consensus recommendations provide useful, practical guidance to clinicians using mifepristone.

Advances in the Medical Treatment of Cushing Disease

Medical therapy has an adjunctive role in management of Cushing disease. Medical therapy is recommended for patients who received pituitary radiotherapy and are awaiting its salutary effects. Medications are used preoperatively to stabilize the condition of seriously ill patients before surgery. Medical therapy is used to control hypercortisolism in patients with uncertain tumor location. Medical therapies available for management of patients with Cushing disease include steroidogenesis inhibitors, centrally acting agents, and glucocorticoid receptor antagonists. All agents require careful monitoring to optimize clinical effectiveness and manage adverse effects. Novel agents in development may expand the armamentarium for management of this condition.

Cushing's Disease

In patients with Cushing's disease (CD), prompt diagnosis and treatment are essential for favorable long-term outcomes, although this remains a challenging task. The differential diagnosis of CD is still difficult in some patients, even with an organized stepwise diagnostic approach. Moreover, despite the use of high-resolution magnetic resonance imaging (MRI) combined with advanced fine sequences, some tumors remain invisible. Surgery, using various surgical approaches for safe maximum tumor removal, still remains the first-line treatment for most patients with CD. Persistent or recurrent CD after unsuccessful surgery requires further treatment, including repeat surgery, medical therapy, radiotherapy, or sometimes, bilateral adrenalectomy. These treatments have their own advantages and disadvantages. However, the most important thing is that this complex disease should be managed by a multidisciplinary team with collaborating experts. In addition, a personalized and individual-based approach is paramount to achieve high success rates while minimizing the occurrence of adverse events and improving the patients' quality of life. Finally, the recent new insights into the pathophysiology of CD at the molecular level are highly anticipated to lead to the introduction of more accurate diagnostic tests and efficacious therapies for this devastating disease in the near future.

The adrenal cortex: Physiology and diseases in human pregnancy

Pregnancy is characterized by marked alterations in the hypothalamic-pituitary-adrenal axis and in the function of the adrenal gland. Some of those alterations have clinical characteristics that are similar to those of adrenal gland disorders. While adrenal disorders are rare among pregnant women, they harbor the potential for significant morbidity if they remain unrecognized and untreated. As the majority of patients with adrenal disorders present with clinical features that are typical of normal pregnancy - diagnosis during pregnancy is not uncommonly delayed. A high index of suspicion must be practiced for these disorders as they might carry severe obstetrical negative outcomes. In this review we will survey the normal function of adrenal glands in pregnancy and the role of adrenal hormones in pregnancy. We will outline the adrenal disorders that commonly present during pregnancy and review the literature on treatment modalities.

Discovery of a Potent Steroidal Glucocorticoid Receptor Antagonist with Enhanced Selectivity against the Progesterone and Androgen Receptors (OP-3633)

Structure-based modification of mifepristone (1) led to the discovery of novel mifepristone derivatives with improved selectivity profile. Addition of a methyl group at the C10 position of the steroid has a significant impact on progesterone receptor (PR) and androgen receptor (AR) activity. Within this series, OP-3633 (15) emerged as a glucocorticoid receptor (GR) antagonist with increased selectivity against PR and AR, improved cytochrome P450 inhibition profile, and significantly improved pharmacokinetic properties compared to 1. Furthermore, 15 demonstrated substantial inhibition of GR transcriptional activity in the GR positive HCC1806 triple negative breast cancer xenograft model. Overall, compound 15 is a promising GR antagonist candidate to clinically evaluate the impact of GR inhibition in reversal or prevention of therapy resistance.

Cushing disease: highlighting the importance of early diagnosis for both de novo and recurrent disease in light of evolving treatment patterns

OBJECTIVE

To highlight and summarize current literature on Cushing disease (CD)-related morbidity and mortality, focusing on residual complications after "cure" and the changing role of pharmacologic therapy in CD.

METHODS

Current journal articles on the consequences of untreated or undertreated CD, CD recurrence, and recent trends in CD treatment were collected from PubMed searches and analyzed in combination in view of the authors' clinical experience.

RESULTS

Timely recognition and treatment of de novo and recurrent CD remains a singular clinical challenge. Chronic excess cortisol exposure leads to potentially irreversible sequelae and death, stressing the importance of early diagnosis and treatment. Disease relapse after primary pituitary adenomectomy is prevalent and recurrence may manifest decades after initial surgery. Increased risk for mortality and hypercortisolism-related complications in postsurgical CD patients may indicate persistent subclinical disease and further underscores the need for cautious, ongoing observation and testing. Potential long-term pharmacologic treatment options (e.g., pasireotide, mifepristone) have recently emerged that may provide biochemical and symptomatic remission for those with refractory CD, or those for whom surgery is contraindicated.

CONCLUSION

Delays in CD diagnosis, management, and follow-up are common and lead to increased adverse metabolic complications and mortality. Rapid recognition and treatment as well as vigilant monitoring are therefore essential. After surgical treatment, some patients may suffer from persistent subclinical CD that remains difficult to detect with routine testing. Although long-term pharmacologic treatment has historically been limited by adverse reactions or escape from response, new treatments may offer more options for patients with refractory disease.

Functioning Pituitary Adenomas - Current Treatment Options and Emerging Medical Therapies

Pituitary adenomas are benign tumours comprising approximately 16% of all primary cranial neoplasms. Functioning pituitary adenomas (prolactinomas, somatotroph, corticotroph, thyrotroph and rarely gonadotroph adenomas) cause complex clinical syndromes and require prompt treatment to reduce associated morbidity and mortality. Treatment approaches include transsphenoidal surgery, medical therapy and radiation. Medical therapy is the primary therapy for prolactinomas, and surgery by a skilled neurosurgeon is the first-line approach for other functioning pituitary adenomas. A multimodal treatment is frequently necessary to achieve biochemical and clinical control, especially, when surgery is not curative or when medical therapy fails. Several emerging, novel, medical treatments for acromegaly, Cushing's disease and prolactinomas are in phase II and III clinical trials and may become effective additions to the current drug armamentarium. The availability of various management options will allow an individualised treatment approach based on the unique tumour type, clinical situation and patient preference.

A unique case of ectopic Cushing's syndrome from a thymic neuroendocrine carcinoma

Ectopic adrenocorticotropic hormone (ACTH) production leading to ectopic ACTH syndrome accounts for a small proportion of all Cushing's syndrome (CS) cases. Thymic neuroendocrine tumors are rare neoplasms that may secrete ACTH leading to rapid development of hypercortisolism causing electrolyte and metabolic abnormalities, uncontrolled hypertension and an increased risk for opportunistic infections. We present a unique case of a patient who presented with a mediastinal mass, revealed to be an ACTH-secreting thymic neuroendocrine tumor (NET) causing ectopic CS. As the diagnosis of CS from ectopic ACTH syndrome (EAS) remains challenging, we emphasize the necessity for high clinical suspicion in the appropriate setting, concordance between biochemical, imaging and pathology findings, along with continued vigilant monitoring for recurrence after definitive treatment. Learning points: Functional thymic neuroendocrine tumors are exceedingly rare. Ectopic Cushing's syndrome secondary to thymic neuroendocrine tumors secreting ACTH present with features of hypercortisolism including electrolyte and metabolic abnormalities, uncontrolled hypertension and hyperglycemia, and opportunistic infections. The ability to undergo surgery and completeness of resection are the strongest prognostic factors for improved overall survival; however, the recurrence rate remains high. A high degree of initial clinical suspicion followed by vigilant monitoring is required for patients with this challenging disease.

Mifepristone in the treatment of the ectopic adrenocorticotropic hormone syndrome

OBJECTIVES

Mifepristone, a glucocorticoid receptor antagonist, can be used to manage hypercortisolism in patients with ectopic adrenocorticotropic hormone syndrome (EAS) when surgical cure is not feasible. Outcomes of EAS patients treated with mifepristone have been limited to reports of isolated cases. We aimed to determine the efficacy and limitations of mifepristone in the treatment of EAS and to compare outcomes with those of patients who underwent bilateral adrenalectomy.

METHOD

A retrospective cohort study of EAS patients from the University of Michigan between 1997 and 2017 was conducted.

RESULTS

Of the 55 patients with EAS, 16 were treated with mifepristone: eight neuroendocrine tumours, two carcinomas and six occult tumours. Treatment with mifepristone was most commonly prompted by psychosis, uncontrolled glucose and/or hypertension. The median maintenance dose was 600 mg/d. Amelioration of psychosis was observed within 48 hours in 3/3 patients, and the glycaemic control was improved in 14/16 patients. The median duration of treatment was 9 months, and three patients were treated for more than 24 months. The overall survival at 24 months was equivalent between patients with EAS treated with mifepristone vs bilateral adrenalectomy (N = 12) (P = 0.6).

CONCLUSIONS

Mifepristone is effective in treating EAS for over 2 years, and survival was not different from that of patients treated with bilateral adrenalectomy. Aggressive concomitant therapy for hypokalaemia and hypertension is necessary.

Discovery of a Potent and Selective Steroidal Glucocorticoid Receptor Antagonist (ORIC-101)

The glucocorticoid receptor (GR) has been linked to therapy resistance across a wide range of cancer types. Preclinical data suggest that antagonists of this nuclear receptor may enhance the activity of anticancer therapy. The first-generation GR antagonist mifepristone is currently undergoing clinical evaluation in various oncology settings. Structure-based modification of mifepristone led to the discovery of ORIC-101 (28), a highly potent steroidal GR antagonist with reduced androgen receptor (AR) agonistic activity amenable for dosing in androgen receptor positive tumors and with improved CYP2C8 and CYP2C9 inhibition profile to minimize drug-drug interaction potential. Unlike mifepristone, 28 could be codosed with chemotherapeutic agents readily metabolized by CYP2C8 such as paclitaxel. Furthermore, 28 demonstrated in vivo antitumor activity by enhancing response to chemotherapy in the GR⁺ OVCAR5 ovarian cancer xenograft model. Clinical evaluation of safety and therapeutic potential of 28 is underway.

Medical Therapy for Cushing's Syndrome in the Twenty-first Century

Medical therapy has a useful adjunctive role in many patients with Cushing's syndrome. Patients with pituitary corticotroph adenomas who have received radiation therapy to the sella require medical therapy until the effects of radiation therapy occur. In addition, patients with Cushing's syndrome who cannot undergo surgery promptly, including those who are acutely ill and cannot safely undergo tumor resection, may benefit from medical therapy as a bridge to surgery. Other possible candidates for medical therapy are those with unresectable tumors or those whose tumor location remains unknown despite adequate diagnostic evaluation.

Cell Cycle Regulators and Lineage-Specific Therapeutic Targets for Cushing Disease

Cell cycle proteins are critical to pituitary development, but their contribution to lineage-specific tumorigenesis has not been well-elucidated. Emerging evidence from in vitro human tumor analysis and transgenic mouse models indicates that G1/S-related cell cycle proteins, particularly cyclin E, p27, Rb, and E2F1, drive molecular mechanisms that underlie corticotroph-specific differentiation and development of Cushing disease. The aim of this review is to summarize the literature and discuss the complex role of cell cycle regulation in Cushing disease, with a focus on identifying potential targets for therapeutic intervention in patients with these tumors.

11β-HSD1 inhibition ameliorates diabetes-induced cardiomyocyte hypertrophy and cardiac fibrosis through modulation of EGFR activity

11β-HSD1 has been recognized as a potential therapeutic target for type 2 diabetes. Recent studies have shown that hyperglycemia leads to activation of 11β-HSD1, increasing the intracellular glucocorticoid levels. Excess glucocorticoids may lead to the clinical manifestations of cardiac injury. Therefore, the aim of this study is to investigate whether 11β-HSD1 activation contributes to the development of diabetic cardiomyopathy. To investigate the role of 11β-HSD1, we administered a selective 11β-HSD1 inhibitor in type 1 and type 2 murine models of diabetes and in cultured cardiomyocytes. Our results show that diabetes increases cortisone levels in heart tissues. 11β-HSD1 inhibitor decreased cortisone levels and ameliorated all structural and functional features of diabetic cardiomyopathy including fibrosis and hypertrophy. We also show that high levels of glucose caused cardiomyocyte hypertrophy and increased matrix protein deposition in culture. Importantly, inhibition of 11β-HSD1 attenuated these changes. Moreover, we show that 11β-HSD1 activation mediates these changes through modulating EGFR phosphorylation and activity. Our findings demonstrate that 11β-HSD1 contributes to the development of diabetic cardiomyopathy through activation of glucocorticoid and EGFR signaling pathway. These results suggest that inhibition of 11β-HSD1 might be a therapeutic strategy for diabetic cardiomyopathy, which is independent of its effects on glucose homeostasis.

Impact of Adrenal Steroids on Regulation of Adipose Tissue

Corticosteroids are secreted by the adrenal glands and control the functions of adipose tissue via the activation of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR). In turn, adipocytes release a large variety of adipokines into the bloodstream, regulating the function of several organs and tissues, including the adrenal glands, hereby controlling corticosteroid production. In adipose tissue, the activation of the MR by glucocorticoids (GC) and aldosterone affects important processes such as adipocyte differentiation, oxidative stress, autophagic flux, adipokine expression as well as local production of GC through upregulation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Notably, the proinflammatory responses induced by the MR are counteracted by activation of the GR, whose activity inhibits the expression of inflammatory adipokines. Both GR and MR are deeply involved in adipogenesis and adipose expansion; hence pharmacological blockade of these two receptors has proven effective against adipose tissue dysfunction in experimental models of obesity and metabolic syndrome (MetS), suggesting a potential use for MR and GR antagonists in these clinical settings. Importantly, obesity and Cushing's syndrome (CS) share metabolic similarities and are characterized by high levels of circulating corticosteroids, which in turn are able to deeply affect adipose tissue. In addition, pharmacological approaches aimed at reducing aldosterone and GC levels, by means of the inhibition of CYP11B2 (aldosterone synthase) or 11β-HSD1, represent alternative strategies to counter the detrimental effects of excessive levels of corticosteroids, which are often observed in obesity and, more general, in MetS. © 2017 American Physiological Society. Compr Physiol 7:1425-1447, 2017.

Recent Progress in the Medical Therapy of Pituitary Tumors

Management of pituitary tumors is multidisciplinary, with medical therapy playing an increasingly important role. With the exception of prolactin-secreting tumors, surgery is still considered the first-line treatment for the majority of pituitary adenomas. However, medical/pharmacological therapy plays an important role in controlling hormone-producing pituitary adenomas, especially for patients with acromegaly and Cushing disease (CD). In the case of non-functioning pituitary adenomas (NFAs), pharmacological therapy plays a minor role, the main objective of which is to reduce tumor growth, but this role requires further studies. For pituitary carcinomas and atypical adenomas, medical therapy, including chemotherapy, acts as an adjuvant to surgery and radiation therapy, which is often required to control these aggressive tumors. In the last decade, knowledge about the pathophysiological mechanisms of various pituitary adenomas has increased, thus novel medical therapies that target specific pathways implicated in tumor synthesis and hormonal over secretion are now available. Advancement in patient selection and determination of prognostic factors has also helped to individualize therapy for patients with pituitary tumors. Improvements in biochemical and "tumor mass" disease control can positively affect patient quality of life, comorbidities and overall survival. In this review, the medical armamentarium for treating CD, acromegaly, prolactinomas, NFA, and carcinomas/aggressive atypical adenomas will be presented. Pharmacological therapies, including doses, mode of administration, efficacy, adverse effects, and use in special circumstances are provided. Medical therapies currently under clinical investigation are also briefly discussed.

Evaluation of Evidence of Adrenal Insufficiency in Trials of Normocortisolemic Patients Treated With Mifepristone

Context:

Adrenal insufficiency (AI) is an important medical concern for clinicians when normocortisolemia is achieved during treatment of endogenous Cushing syndrome (CS).

Objective:

To examine symptoms of potential AI in a large population of normocortisolemic patients without CS treated with mifepristone, a glucocorticoid receptor antagonist indicated for the treatment of patients with CS.

Methods:

We conducted a pooled safety analysis of five phase 3, placebo-controlled clinical trials of normocortisolemic adults without CS but diagnosed with psychotic depression (n = 1460). Patients were treated with once-daily mifepristone 300 mg (n = 110), 600 mg (n = 471), or 1200 mg (n = 252), or placebo (n = 627) administered for 7 consecutive days. All study investigators were trained and instructed to assess for the development of AI and to report all adverse events (AEs) at each clinic visit. The incidence of (1) AI or similar terminologies and that of (2) ≥3 concurrent symptoms that could be associated with AI was evaluated.

Results:

Mean serum cortisol and adrenocorticotropic hormone levels increased dose dependently with mifepristone treatment. There were no reports of AI and no significant differences between the mifepristone-treated and placebo groups in the incidence of patients having ≥3 AEs that could be associated with AI.

Conclusions:

This large pooled analysis of normocortisolemic patients without CS found no cases of AI and no differences between mifepristone therapy and placebo in the incidence of symptom combinations mimicking AI, even at the highest (1200 mg) dose. These findings further add clinically important insights to the safety and tolerability profile of mifepristone therapy.

Updates on the role of adrenal steroidogenesis inhibitors in Cushing's syndrome: a focus on novel therapies

PURPOSE

Endogenous Cushing's syndrome (CS) is a rare disease that results from exposure to high levels of cortisol; Cushing's disease (CD) is the most frequent form of CS. Patients with CS suffer from a variety of comorbidities that increase the risk of mortality. Surgical resection of the disease-causing lesion is generally the first-line treatment of CS. However, some patients may not be eligible for surgery due to comorbidities, and approximately 25 % of patients, especially those with CD, have recurrent disease. For these patients, adrenal steroidogenesis inhibitors may control cortisol elevation and subsequent symptomatology. CS is rare overall, and clinical studies of adrenal steroidogenesis inhibitors are often small and, in many cases, data are limited regarding the efficacy and safety of these treatments. Our aim was to better characterize the profiles of efficacy and safety of currently available adrenal steroidogenesis inhibitors, including drugs currently in development.

METHODS

We performed a systematic review of the literature regarding adrenal steroidogenesis inhibitors, focusing on novel drugs.

RESULTS

Currently available adrenal steroidogenesis inhibitors, including ketoconazole, metyrapone, etomidate, and mitotane, have variable efficacy and significant side effects, and none are approved by the US Food and Drug Administration for CS. Therefore, there is a clear need for novel, prospectively studied agents that have greater efficacy and a low rate of adverse side effects. Efficacy and safety data of current and emerging adrenal steroidogenesis inhibitors, including osilodrostat (LCI699) and levoketoconazole (COR-003), show promising results that will have to be confirmed in larger-scale phase 3 studies (currently ongoing).

CONCLUSIONS

The management of CS, and particularly CD, remains challenging. Adrenal steroidogenesis inhibitors can be of major interest to control the hypercortisolism at any time point, either before or after surgery, as discussed in this review.

Update on medical treatment for Cushing's disease

Cushing's disease (CD) is the most common cause of endogenous Cushing's syndrome (CS). The goal of treatment is to rapidly control cortisol excess and achieve long-term remission, to reverse the clinical features and reduce long-term complications associated with increased mortality. While pituitary surgery remains first line therapy, pituitary radiotherapy and bilateral adrenalectomy have traditionally been seen as second-line therapies for persistent hypercortisolism. Medical therapy is now recognized to play a key role in the control of cortisol excess. In this review, all currently available medical therapies are summarized, and novel medical therapies in phase 3 clinical trials, such as osilodrostat and levoketoconazole are discussed, with an emphasis on indications, efficacy and safety. Emerging data suggests increased efficacy and better tolerability with these novel therapies and combination treatment strategies, and potentially increases the therapeutic options for treatment of CD. New insights into the pathophysiology of CD are highlighted, along with potential therapeutic applications. Future treatments on the horizon such as R-roscovitine, retinoic acid, epidermal growth factor receptor inhibitors and somatostatin-dopamine chimeric compounds are also described, with a focus on potential clinical utility.

Effects of Intraperitoneal Administration of Mifepristone on Glucocorticoid Status of Experimental Animals

We studied the content of corticosterone and its precursors in the adrenal glands, corticosterone in blood serum and daily urine of rats, and activity of first and second isoforms of 11β-hydroxysteroid dehydrogenase in the liver and kidneys of rats after 15 daily intraperitoneal injections of 0.9% NaCl or glucocorticoid receptor blocker mifepristone in 0.9% NaCl. Daily injections of NaCl reduced the levels of pregnenolone, progesterone, and corticosterone in the adrenal glands, increased corticosterone excretion with urine, enhanced activity of the first isoform of 11β-hydroxysteroid dehydrogenase in the liver and reduction in activity of the second isoform of this enzyme in the kidneys. These changes are typical manifestations of chronic stress. Mifepristone restored pregnenolone content in the adrenal glands and increase in corticosterone concentration in the blood. Under these conditions, activity of the first isoform of 11β-hydroxysteroid dehydrogenase in the liver did not change, and a decrease in activity of the second isoform of the enzyme in the kidneys was less pronounced. The results suggest that mifepristone abolished the stress-mediated increase in activity of the first isoform of 11β-hydroxysteroid dehydrogenase in the liver and reduced local production of glucocorticoid hormones and their metabolic effects in hepatocytes.

The treatment with pasireotide in Cushing's disease: effects of long-term treatment on tumor mass in the experience of a single center

Pasireotide is the first medical therapy officially approved for the treatment of adult patients with Cushing's disease (CD) who experienced a failure of pituitary surgery or are not candidates for surgery and require medical therapeutic intervention. The current study aimed at investigating the effects of long-term treatment with pasireotide (up to 24 months) on tumor mass in a group of patients with CD, participating to a phase III study. Fourteen CD patients entered the phase III clinical trial CSOM230B2305 at Naples Center, and eight (seven women, one man, aged 38.9 ± 17.6 years), including seven with a microadenoma and one with a macroadenoma, received treatment with pasireotide at the dose of 600-1200 µg bid for at least 6 months, and were considered for the analysis of the study. These eight patients were subjected to the evaluation of pituitary tumor volume by pituitary MRI, together with the evaluation of urinary cortisol levels, at baseline and every 6 months for the entire period of treatment. Pasireotide treatment induced full disease control in 37.5 % and partial disease control in 37.5 % after 6 months, whereas full and partial disease control after 12 months was obtained in 28.6 % and in 57.1 % of patients, respectively. A significant (>25 %) reduction in tumor volume was found in 62.5 % and in 100 % of patients, after 6 and 12 months, respectively. In particular, after 6 months, a slight tumor shrinkage (between 25.1 and 50 %) was observed in 25 %, moderate (50.1-75 %) in 25 %, and marked (>75 %) in 12.5 % of patients, whereas after 12 months, a slight tumor shrinkage was observed in 43 %, moderate in 14 %, and marked in 43 % of patients. In 25 % of patients (two patients), a marked tumor shrinkage was recorded, with tumor mass disappearance in one case; this tumor shrinkage was associated to rapid and sustained biochemical remission up to 24 months of continuous pasireotide treatment. These two cases represent the first cases with a documentation of such a notable effect of pasireotide on tumor mass. Pasireotide induces significant tumor shrinkage in 62.5 % of patients after 6 months and in 100 % of patients after 12 months, and occasionally induces a radiological disappearance of the tumor. This evidence supports and strengthens the role of pasireotide as medical treatment specifically addressed to patients with CD, particularly in those who had unsuccessful pituitary surgery, or are not candidates for surgery.

Mifepristone Treatment of Cushing's Syndrome in a Pediatric Patient

Cushing's syndrome (CS) in the pediatric population is challenging to diagnose and treat. Although next-generation medical therapies are emerging for adults with CS, none are currently approved or used in children. Here we describe the first use of mifepristone, a glucocorticoid receptor antagonist, to treat CS in a pediatric subject. The patient, a 14-year-old girl with an 18-month history of metastatic neuroendocrine carcinoma, suffered from fatigue, profound myopathy, irritability, and depression. She was found to have hypertension, hypokalemia, and worsening control of her preexisting type 1 diabetes. In this report, we detail our clinical evaluation that confirmed CS caused by an ectopic adrenocorticotropic hormone secreting tumor. Surgical and radiation therapies were not pursued because of her poor functional status and limited life expectancy, and medical treatment of CS was indicated for symptom relief. Mifepristone treatment provided rapid improvement in glycemic control, insulin resistance, and hypertension as well as significant diminishment of her myopathy and fatigue. Hypokalemia was managed with an oral potassium replacement and dose escalation of spironolactone; no other significant adverse effects were observed. Despite successful palliation of Cushing's signs and symptoms, the patient died of progression of her cancer. This case demonstrates the safety and efficacy of mifepristone treatment in a pediatric patient with symptomatic, ectopic CS. We conclude that, in appropriate pediatric patients with CS, glucocorticoid receptor antagonism with mifepristone should be considered to control the effects of hypercortisolism and to improve quality of life.

Glucocorticoid receptor activation inhibits chemotherapy-induced cell death in high-grade serous ovarian carcinoma

OBJECTIVES

To test the hypothesis that glucocorticoid receptor (GR) activation increases resistance to chemotherapy in high-grade serous ovarian cancer (HGS-OvCa) and that treatment with a GR antagonist will improve sensitivity to chemotherapy.

METHODS

GR expression was assessed in OvCa cell lines by qRT-PCR and Western blot analysis and in xenografts and primary human tumors using immunohistochemistry (IHC). We also examined the effect of GR activation versus inhibition on chemotherapy-induced cytotoxicity in OvCa cell lines and in a xenograft model.

RESULTS

With the exception of IGROV-1 cells, all OvCa cell lines tested had detectable GR expression by Western blot and qRT-PCR analysis. Twenty-five out of the 27 human primary HGS-OvCas examined expressed GR by IHC. No cell line expressed detectable progesterone receptor (PR) or androgen receptor (AR) by Western blot analysis. In vitro assays showed that in GR-positive HeyA8 and SKOV3 cells, dexamethasone (100nM) treatment upregulated the pro-survival genes SGK1 and MKP1/DUSP1 and inhibited carboplatin/gemcitabine-induced cell death. Concurrent treatment with two GR antagonists, either mifepristone (100nM) or CORT125134 (100nM), partially reversed these effects. There was no anti-apoptotic effect of dexamethasone on chemotherapy-induced cell death in IGROV-1 cells, which did not have detectable GR protein. Mifepristone treatment alone was not cytotoxic in any cell line. HeyA8 OvCa xenograft studies demonstrated that adding mifepristone to carboplatin/gemcitabine increased tumor shrinkage by 48% compared to carboplatin/gemcitabine treatment alone (P=0.0004).

CONCLUSIONS

These results suggest that GR antagonism sensitizes GR+ OvCa to chemotherapy-induced cell death through inhibition of GR-mediated cell survival pathways.

Treatment of Cushing's Syndrome: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for treating Cushing's syndrome.

PARTICIPANTS

Participants include an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. The European Society for Endocrinology co-sponsored the guideline.

EVIDENCE

The Task Force used the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned three systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

The Task Force achieved consensus through one group meeting, several conference calls, and numerous e-mail communications. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Treatment of Cushing's syndrome is essential to reduce mortality and associated comorbidities. Effective treatment includes the normalization of cortisol levels or action. It also includes the normalization of comorbidities via directly treating the cause of Cushing's syndrome and by adjunctive treatments (eg, antihypertensives). Surgical resection of the causal lesion(s) is generally the first-line approach. The choice of second-line treatments, including medication, bilateral adrenalectomy, and radiation therapy (for corticotrope tumors), must be individualized to each patient.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

ASSOCIATION BETWEEN MIFEPRISTONE DOSE, EFFICACY, AND TOLERABILITY IN PATIENTS WITH CUSHING SYNDROME

OBJECTIVE

To examine the relationship between dose, clinical response (based on independent evaluation of metabolic, physical, neurologic, and social assessments), and safety of mifepristone treatment in patients with endogenous Cushing syndrome (CS).

METHODS

This post hoc analysis included 40 clinical responders and 50 participants who received a dose of mifepristone (safety population) in the 24-week phase 3 SEISMIC (Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing Syndrome) trial. The dose of mifepristone at the initial clinical response was analyzed, and the rate of serious adverse events (SAEs) and AEs reported in ≥20% of patients were compared to average mifepristone doses over time.

RESULTS

Among the clinical responders, 85% and 35% had their initial clinical responses at mifepristone doses ≥600 and ≥900 mg/day, respectively. The SAE rate did not increase with a higher dose over time. The AE rates for fatigue, headache, nausea, and peripheral edema declined significantly at weeks 16 to 24 (all P<.05 vs. weeks 1-2) as the study progressed and mifepristone doses were increased. Other AEs such as hypokalemia, vomiting, and decreased appetite did not significantly increase from weeks 1 to 2 as mifepristone doses were increased.

CONCLUSIONS

The majority of clinical responders in the SEISMIC trial received mifepristone doses ≥600 mg/day suggesting that higher doses were required to achieve optimal clinical benefit in patients with endogenous CS. Notably, mifepristone dose escalations did not result in any significant or concordant increase in the rates of SAEs and common AEs.

Current approaches to the pharmacological management of Cushing's disease

If treatment of Cushing's disease (CD) by surgery is not successful, medical therapy is often required. Long-term use of metyrapone is limited by hirsutism and hypertension and escape because of increased ACTH levels. Although ketoconazole can normalize cortisol levels in 50%, liver toxicity limits its use. Mitotane, an adrenolytic agent, has had minimal use for benign disease. Etomidate is useful when rapid reduction in cortisol levels is needed. Cabergoline can normalize cortisol levels in CD in about one-third of patients and is well tolerated. Pasireotide can normalize cortisol levels in CD in about 25% but causes worsening of glucose tolerance in most patients. Mifepristone, a blocker of cortisol receptors, improves clinical aspects of CD in most patients but cortisol and ACTH measurements do not reflect clinical activity and adrenal insufficiency, hypokalemia, and endometrial hyperplasia can occur. Combinations of drugs can be tried in patients resistant to monotherapy.

Medical therapy for Cushing's disease: adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers

Morbidity and mortality in Cushing's disease (CD) patients are increased if patients are not appropriately treated. Surgery remains the first line therapy, however the role of medical therapy has become more prominent in patients when biochemical remission is not achieved/or recurs after surgery, while waiting effects of radiation therapy or when surgery is contraindicated. Furthermore, use of preoperative medical therapy has been also recognized. In addition to centrally acting therapies (reviewed elsewhere in this special issue), adrenal steroidogenesis inhibitors, and glucocorticoid receptor antagonists are frequently used. A PubMed search of all original articles or abstracts detailing medical therapy in CD, published within 12 months (2013-2014), were identified and pertinent data extracted. Although not prospectively studied, ketoconazole and metyrapone have been the most frequently used medical therapies. A large retrospective ketoconazole study showed that almost half of patients who continued on ketoconazole therapy achieved biochemical control and clinical improvement; however almost 20% discontinued ketoconazole due to poor tolerability. Notably, hepatotoxicity was usually mild and resolved after drug withdrawal. Etomidate remains the only drug available for intravenous use. A new potent inhibitor of both aldosterone synthase and 11β-hydroxylase, following the completion of a phase II study LCI699 is being studied in a large phase III with promising results. Mifepristone, a glucocorticoid receptor antagonist, has been approved for hyperglycemia associated with Cushing's syndrome based on the results of a prospective study where it produced in the majority of patients' significant clinical and metabolic improvement. Absence of both a biochemical marker for remission and/or diagnosis of adrenal insufficiency remain, however, a limiting factor. Patient characteristics and preference should guide the choice between different medications in the absence of clinical trials comparing any of these therapies. Despite significant progress, there is still a need for a medical therapy that is more effective and with less adverse effects for patients with CD.

Medical treatment of Cushing disease: new targets, new hope

This article provides an update on current medical therapies for the treatment of Cushing disease. This information will be of value in determining patients' suitability for certain medical treatments. An approach of combining drugs from the same or different classes could potentially increase the number of patients in whom Cushing can be controlled while minimizing adverse effects, although larger studies are needed. Successful clinical management of patients with Cushing disease remains a challenge.

Cushing's syndrome in childhood: update on genetics, treatment, and outcomes

PURPOSE OF REVIEW

To provide an update on the genes associated with Cushing's syndrome in children, as well as to familiarize the clinician with recent treatment guidelines and outcome data for children with Cushing's syndrome.

RECENT FINDINGS

The list of genes associated with Cushing's syndrome continues to grow. In addition, treatment for childhood Cushing's syndrome is evolving. As long-term follow-up data on children becomes available, clinicians need to be aware of the issues that require attention.

SUMMARY

Knowledge of the specific genetic causes of Cushing's syndrome has potential implications for treatment, surveillance, and counseling. Advances in surgical technique, radiation modalities, and medical therapies offer the potential for additional treatment options in Cushing's syndrome. Early identification and management of post-treatment morbidities in children treated for Cushing's syndrome is crucial in order to optimize care.

Changes in plasma ACTH levels and corticotroph tumor size in patients with Cushing's disease during long-term treatment with the glucocorticoid receptor antagonist mifepristone

CONTEXT

Pituitary effects of long-term therapy with mifepristone, a glucocorticoid receptor antagonist, in Cushing's disease (CD) patients are not well understood.

OBJECTIVE

Our objective was to report changes in ACTH and pituitary magnetic resonance imaging (MRI) findings during long-term use of mifepristone in CD patients.

DESIGN AND SETTING

The Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing's Syndrome (SEISMIC) was a 24-week, open-label study of mifepristone, and its long-term extension (LTE) is a multicenter U.S. study.

PATIENTS

Forty-three CD patients (mean age 45.3 years) were enrolled in SEISMIC with 27 continuing into the LTE study.

INTERVENTIONS

Mifepristone (300-1200 mg) was administered once daily.

MAIN OUTCOME MEASURES

ACTH and pituitary MRI were assessed at baseline and at regular intervals during treatment.

RESULTS

A ≥2-fold increase in ACTH was observed in 72% of patients treated for a median duration of 11.3 months. The mean peak increase in ACTH was 2.76 ± 1.65-fold during SEISMIC, and mean ACTH concentrations remained stable during the LTE. ACTH was directly correlated with mifepristone dose and declined to near baseline levels after mifepristone discontinuation. Tumor regressed in 2 patients and progressed in 3 patients with macroadenomas. An additional microadenoma was identified after 25 months of treatment after a baseline tumor-negative MRI.

CONCLUSIONS

In the largest prospective study to date, long-term mifepristone treatment increased ACTH in approximately two-thirds of patients with CD. ACTH elevations were observed within the first few weeks of treatment, were dose-dependent, and generally remained stable over time. Corticotroph tumor progression and regression may occur over time, but patients may have significant increases in ACTH levels without evidence of tumor growth.

Recent advances in the medical treatment of Cushing's disease

Cushing’s disease is a condition of hypercortisolism caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma. While rare, it is associated with significant morbidity and mortality, which suggests that early and aggressive intervention is required. The primary, definitive therapy for patients with Cushing’s disease in the majority of patients is pituitary surgery, generally performed via a transsphenoidal approach. However, many patients will not achieve remission or they will have recurrences. The consequences of persistent hypercortisolism are severe and, as such, early identification of those patients at risk of treatment failure is exigent. Medical management of Cushing’s disease patients plays an important role in achieving long-term remission after failed transsphenoidal surgery, while awaiting effects of radiation or before surgery to decrease the hypercortisolemia and potentially reducing perioperative complications and improving outcome. Medical therapies include centrally acting agents, adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers. Furthermore, several new agents are in clinical trials. To normalize the devastating disease effects of hypercortisolemia, it is paramount that successful patient disease management includes individualized, multidisciplinary care, with close collaboration between endocrinologists, neurosurgeons, radiation oncologists, and general surgeons. This commentary will focus on recent advances in the medical treatment of Cushing’s, with a focus on newly approved ACTH modulators and glucocorticoid receptor blockers.

Medical management of Cushing's disease

Cushing's disease (CD), caused by excess adrenocorticotropin secretion from tumorous pituitary corticotrophs, is associated with substantial morbidity and mortality. The primary, definitive therapy for patients with CD is selective pituitary adenomectomy, generally performed via a transsphenoidal approach. Medical therapy has an important adjunctive role in the management of patients with CD, including preoperative patient preparation in patients with severe disease, and temporizing management of hypercortisolism while awaiting the effects of radiation therapy to occur in patients who are not in remission postoperatively. Medical therapy can also be used in patients with hypercortisolism of unclear origin or in the few patients who decline or are unfit for surgery. Available medical options for patients with CD include centrally acting agents (cabergoline and pasireotide), steroidogenesis inhibitors (ketoconazole, metyrapone, mitotane and etomidate) and a glucocorticoid receptor antagonist (mifepristone). Pasireotide and mifepristone have been recently granted regulatory approval in some countries for use in patients with CD, whereas other medications are used "off label" in this patient population. As clinical trials using comparator agents have not been reported, the choice between different medications is based on patient characteristics and preference. Despite impressive advances in pharmacotherapy for patients with CD, much remains to be done. The long term efficacy and safety of medical therapies for hypercortisolism need to be evaluated and the role of combination therapy must be further characterized. As the pathogenesis of CD becomes better understood at the molecular level, it is likely that novel, targeted medical therapies will be developed to treat CD.