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

Medical Therapy of Endogenous Cushing's Syndrome with Steroidogenesis Inhibitors: Treatment Rationale, Available Drugs, and Therapeutic Effects

Endogenous Cushing's syndrome (CS) is a rare disease characterized by a glucocorticoid excess. If inadequately treated, hypercortisolism can lead to increased morbidity and mortality. Surgical removal of the underlying tumor is the first-line treatment but is sometimes not feasible or even contraindicated. Additionally, in cases with severe CS, rapid control of hypercortisolism may be required. In these scenarios, steroidogenesis inhibitors represent a therapeutic alternative to surgery. Over the last years, the knowledge of the broad therapeutic effects of steroidogenesis inhibitors per se and the number of available drugs have increased. However, large comparative studies are still lacking. Accordingly, the decision on which drug to be used in a certain patient or clinical setting may be difficult. This review aims to summarize the main characteristics of steroidogenesis inhibitors.

Challenges in the postsurgical recovery of cushing syndrome: glucocorticoid withdrawal syndrome

Glucocorticoid withdrawal syndrome is a challenging clinical phenomenon that can complicate the postsurgical recovery of Cushing syndrome. It is characterized by physical tolerance and dependence to supraphysiologic glucocorticoid exposure during active Cushing syndrome followed by the abrupt decline in cortisol levels after surgical treatment. The symptoms of glucocorticoid withdrawal often overlap with those of postoperative adrenal insufficiency and can be difficult for patients to cope with and for clinicians to treat. This mini review will discuss the clinical characteristics, pathophysiology, and management of glucocorticoid withdrawal syndrome while highlighting recent data in the field.

Response to Osilodrostat Therapy in Adrenal Cushing's Syndrome

Cushing's disease (CD) is the most common cause of endogenous hypercortisolism. Osilodrostat was demonstrated to be efficient in treating CD, and the mean average dose required for CD control was <11 mg/day. Potential differences in osilodrostat treatment between cortisol-producing adenoma (CPA) and CD have not been reported. The aim of this study was to present two patients with CPA in whom significant differences in the response to therapy compared to CD were found. We demonstrated a case of inverse response of cortisol levels with adrenal tumor progression during the initial dose escalation (Case 1). Simultaneously, severe exaggeration of hypercortisolism symptoms and life-threatening hypokalemia occurred. A further rapid dose increase resulted in the first noticeable cortisol response at a dose of 20 mg/day, and a full response at a dose of 45 mg/day. We also present a case that was initially resistant to therapy (Case 2). The doses required to achieve the first response and the full response were the same as those for Case 1. Our study demonstrated that osilodrostat therapy in patients with CPA may require a different approach than that in CD, with higher doses, faster dose escalation, and a possible initial inverse response or lack of response.

Osilodrostat: A Novel Potent Inhibitor of 11-Beta-Hydroxylase for the Treatment of Cushing's Syndrome

Osilodrostat is a novel potent oral steroidogenesis inhibitor with a non-steroidal chemical structure, recently approved for the treatment of adult patients with endogenous Cushing's syndrome, and Cushing's disease not cured bytab pituitary surgery or in whom pituitary surgery is not an option. Osilodrostat has been evaluated in different multicentre phase II and III clinical studies, and has shown to have notable effects, such as significant reductions in cortisol secretion, associated with significant improvement in body weight, blood pressure, glucose metabolism, lipid profile, psychological status and quality of life. The favourable safety profile, combined with the relevant efficacy, could make osilodrostat suitable as medical treatment in several phases of the Cushing's syndrome treatment journey: before surgery, as preoperative treatment, or instead of surgery, in cases where surgery is not an option or refused, as first-line treatment; after surgery, in cases of persistent or recurrent disease, as second-line treatment; after second surgery or radiotherapy following pituitary surgery as bridging treatment waiting for the definitive disease control, as third-line treatment. Further real-world clinical experience data are needed to confirm the current knowledge.

Iatrogenic adrenal insufficiency in adults

Iatrogenic adrenal insufficiency (IAI) is the most common form of adrenal insufficiency in adult patients, although its overall exact prevalence remains unclear. IAI is associated with adverse clinical outcomes, including adrenal crisis, impaired quality of life and increased mortality; therefore, it is imperative that clinicians maintain a high index of suspicion in patients at risk of IAI to facilitate timely diagnosis and appropriate management. Herein, we review the major causes, clinical consequences, diagnosis and care of patients with IAI. The management of IAI, particularly glucocorticoid-induced (or tertiary) adrenal insufficiency, can be particularly challenging, and the provision of adequate glucocorticoid replacement must be balanced against minimizing the cardiometabolic effects of excess glucocorticoid exposure and optimizing recovery of the hypothalamic-pituitary-adrenal axis. We review current treatment strategies and their limitations and discuss developments in optimizing treatment of IAI. This comprehensive Review aims to aid clinicians in identifying who is at risk of IAI, how to approach screening of at-risk populations and how to treat patients with IAI, with a focus on emergency management and prevention of an adrenal crisis.

Aldosterone and aldosterone synthase inhibitors in cardiorenal disease

Modulation of the renin-angiotensin-aldosterone system is a foundation of therapy for cardiovascular and kidney diseases. Excess aldosterone plays an important role in cardiovascular disease, contributing to inflammation, fibrosis, and dysfunction in the heart, kidneys, and vasculature through both genomic and mineralocorticoid receptor (MR)-mediated as well as nongenomic mechanisms. MR antagonists have been a key therapy for attenuating the pathologic effects of aldosterone but are associated with some side effects and may not always adequately attenuate the nongenomic effects of aldosterone. Aldosterone is primarily synthesized by the CYP11B2 aldosterone synthase enzyme, which is very similar in structure to other enzymes involved in steroid biosynthesis including CYP11B1, a key enzyme involved in glucocorticoid production. Lack of specificity for CYP11B2, off-target effects on the hypothalamic-pituitary-adrenal axis, and counterproductive increased levels of bioactive steroid intermediates such as 11-deoxycorticosterone have posed challenges in the development of early aldosterone synthase inhibitors such as osilodrostat. In early-phase clinical trials, newer aldosterone synthase inhibitors demonstrated promise in lowering blood pressure in patients with treatment-resistant and uncontrolled hypertension. It is therefore plausible that these agents offer protection in other disease states including heart failure or chronic kidney disease. Further clinical evaluation will be needed to clarify the role of aldosterone synthase inhibitors, a promising class of agents that represent a potentially major therapeutic advance.

Cushing's Disease: Long-Term Effectiveness and Safety of Osilodrostat in a Polish Group of Patients with Persistent Hypercortisolemia in the Experience of a Single Center

Osilodrostat is a potent oral steroidogenesis inhibitor that has emerged as the new medical agent for patients with Cushing's disease (CD) requiring long-term medical therapy for hypercortisolemia control. Its efficacy and safety have been assessed in clinical trials; however, real-world evidence is still scarce. This study aimed to investigate the long-term treatment (156 weeks) clinical and biochemical effect of osilodrostat in six patients with CD at a single center in Poland, initially participating in the LINC4 study. At week 36, all six patients met the key secondary endpoint of the LINC4 trial, achieving normalization of median urinary free cortisol. Osilodrostat treatment allowed for complete disease control in all patients and none of the patients was excluded due to the lack of treatment effectiveness in 156 weeks of follow-up. All patients demonstrated significant improvement from baseline on most metabolic and cardiovascular parameters, which was most evident at week 36 and sustained throughout the study period. This study supports and strengthens the role of osilodrostat as an effective long-term medical treatment in patients with CD. We also present three patient case histories in detail to highlight the clinical situations that endocrinologists might face during osilodrostat therapy.

Endocrine causes of hypertension: literature review and practical approach

Hypertension (HTN) affects more than 30% of adults worldwide. It is the most frequent modifiable cardiovascular (CV) risk factor, and is responsible for more than 10 million death every year. Among patients with HTN, we usually distinguish secondary HTN, that is HTN due to an identified cause, and primary HTN, in which no underlying cause has been found. It is estimated that secondary hypertension represents between 5 and 15% of hypertensive patients [1]. Therefore, routine screening of patients for secondary HTN would be too costly and is not recommended. In addition to the presence of signs suggesting a specific secondary cause, screening is based on specific criteria. Identifying secondary HTN can be beneficial for patients in certain situations, because it may lead to specific treatments, and allow better control of blood pressure and sometimes even a cure. Besides, it is now known that secondary HTN are more associated with morbidity and mortality than primary HTN. The main causes of secondary HTN are endocrine and renovascular (mainly due to renal arteries abnormalities). The most frequent endocrine cause is primary aldosteronism, which diagnosis can lead to specific therapies. Pheochromocytoma and Cushing syndrome also are important causes, and can have serious complications. Other causes are less frequent and can be suspected on specific situations. In this article, we will describe the endocrine causes of HTN and discuss their treatments.

Future treatments in hypertension: Can we meet the unmet needs of patients?

The prevalence of arterial hypertension is approximately 47% in the United States and 55% in Europe. Multiple different medical therapies are used to treat hypertension including diuretics, beta blockers, calcium channel blockers, angiotensin receptor blockers, angiotensin converting enzyme inhibitors, alpha blockers, central acting alpha receptor agonists, neprilysin inhibitors and vasodilators. However, despite the numerous number of medications, the prevalence of hypertension is on the rise, a considerable proportion of the hypertensive population is resistant to these therapeutic modalities and a definitive cure is not possible with the current treatment approaches. Therefore, there is a need for novel therapeutic strategies to provide better treatment and control of hypertension. In this review, our aim is to describe the latest developments in the treatment of hypertension including novel medication classes, gene therapies and RNA-based modalities.

Pituitary and SARS CoV-2: An unremitting conundrum

There is increased interest related to the impact of coronavirus disease 19 (COVID-19) on the endocrine system and in particular on the pituitary gland. Over the course of the severe infection with acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there are both acute and delayed effects on the pituitary, related to infection and/or treatment. Hypopituitarism, pituitary apoplexy and hypophysitis have been all reported, as well as arginine vasopressin deficiency (diabetes insipidus) and syndrome of inappropriate antidiuretic hormone secretion. Furthermore, patients with acromegaly, Cushing's disease and hypopituitarism are theoretically at increased risk of complications with COVID-19 and require close monitoring. Evidence regarding pituitary dysfunction in patients with COVID-19 continues to be gathered, as the breadth and depth of knowledge also continues to rapidly evolve. This review summarizes data analysis to date on the possible effects of COVID-19 and COVID-19 vaccination on patients with normal pituitary function and patients with known pituitary pathology. Though clinical systems were significantly affected, it seems there is no overall loss of biochemical control in patients with certain pituitary pathologies.

Prolonged adrenocortical blockade following discontinuation of Osilodrostat

INTRODUCTION

Osilodrostat is the newest approved steroidogenic inhibitor drug for the treatment of hypercortisolism. In this article, we describe 3 patients who experienced a previously undescribed adverse event: a prolonged adrenocortical blockade following treatment cessation.

METHODS

Patient records showing a history of successful hypercortisolism control with Osilodrostat followed by at least 4 weeks of treatment interruption were reviewed. Patient characteristics and hormonal dosage were analyzed.

RESULTS

Persistence of adrenocortical blockade was found in 3 patients and lasted from 6 weeks to 9 months depending on patients. This phenomenon manifested in patients regardless of lower or higher daily Osilodrostat doses (2-10 mg) and total treatment duration did not seem to predict the severity of the blockade.

CONCLUSION

The finding of this previously undescribed side effect highlights the importance of continuing adrenal function monitoring after Osilodrostat interruption to prevent adrenal crisis in patients at risk.

Clinical Utility of Osilodrostat in Cushing's Disease: Review of Currently Available Literature

Cushing's disease (CD) is caused by endogenous hypercortisolism as a result of adrenocorticotropin (ACTH) secretion from a pituitary tumor. The condition is associated with multiple comorbidities and increased mortality. First-line therapy for CD is pituitary surgery, performed by an experienced pituitary neurosurgeon. Hypercortisolism may often persist or recur after initial surgery. Patients with persistent or recurrent CD will generally benefit from medical therapy, often administered to patients who underwent radiation therapy to the sella and are awaiting its salutary effects. There are three groups of medications directed against CD, including pituitary-targeted medications that inhibit ACTH secretion from tumorous corticotroph cells, adrenally-directed medications that inhibit adrenal steroidogenesis and a glucocorticoid receptor (GR) antagonist. The focus of this review is osilodrostat, a steroidogenesis inhibitor. Osilodrostat (LCI699) was initially developed to lower serum aldosterone levels and control hypertension. However, it was soon realized that osilodrostat also inhibits 11-beta hydroxylase (CYP11B1), leading to a reduction in serum cortisol levels. The focus of drug development then shifted from treatment of hypertension to treatment of hypercortisolism in CD. In a series of studies (LINC 1 through 4), osilodrostat was shown to be effective in normalizing 24-h urinary free cortisol (UFC) in the majority of treated patients and was approved for patients with CD who have failed surgery or are not surgical candidates. Further study is needed to examine the role of combination therapy as well as long-term outcomes of treated patients. Osilodrostat was shown to have an overall good safety profile. Most common adverse effects include nausea, headache, fatigue, arthralgias, dizziness, prolonged QTc interval, hypokalemia. In females, the drug can cause hirsutism and acne. Osilodrostat is administered twice daily, making it a good choice for patients with difficulty adhering to more complex regimens. Osilodrostat has an important, albeit adjunctive, role in the management of patients with CD.