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.

Discontinuation of Drug Treatment in Cushing's Disease Not Cured by Pituitary Surgery

OBJECTIVE

When transsphenoidal surgery (TSS) does not cure Cushing's disease (CD), 4 treatments are available: drug treatment (DT), second TSS (2nd TSS), bilateral adrenalectomy (BA), and pituitary radiotherapy (PR). DT is attractive but supposes long-term continuation, which we aimed to evaluate.

DESIGN AND METHODS

Retrospective study, in a center prioritizing 2nd TSS, of 36 patients, including 19 with TSS failure and 17 with recurrence, out of 119 patients with CD treated by a first TSS, average follow-up 6.1 years (95% confidence interval 5.27-6.91). Control was defined as normalization of urinary free cortisol (UFC) and final treatment (FT) as the treatment allowing control at last follow-up. We also analyzed discontinuation rates of DT in published CD prospective clinical trials.

RESULTS

Control was achieved in 33/36 patients (92%). DT was initiated in 29/36 patients (81%), allowing at least 1 normal UFC in 23/29 patients (79%) but was discontinued before last follow-up in 18/29 patients (62%). DT was FT in 11/29 patients (38%), all treated with cortisol synthesis inhibitors. Second TSS was FT in 8/16 (50%), BA in 14/14 (100%), and PR in 0/5. In published trials, discontinuation of DT was 11% to 51% at 1 year and 32% to 74% before 5 years.

CONCLUSION

DT allowed at least 1 normal UFC in 23/29 patients (79%) but obtained long-term control in only 11/29 (38%), as discontinuation rate was high, although similar to published data. Interestingly, a successful 2nd TSS was the cause for discontinuing efficient and well-tolerated DT in 5 patients. Further studies will show whether different strategies with cortisol synthesis inhibitors may allow for a lower discontinuation rate in patients not candidates for a 2nd TSS so that BA may be avoided in these patients.

A Case of an Ectopic ACTH-Producing Tumor With Adrenal Shrinkage During Osilodrostat Administration

Ectopic adrenocorticotropin (ACTH)-secreting tumors are among the causes of ACTH-dependent Cushing syndrome. When surgical resection of the primary lesion is not feasible, medications such as metyrapone, mitotane, and ketoconazole have been used to control hypercortisolism. This report presents a case treated with the novel drug osilodrostat, wherein the patient's adrenal glands exhibited shrinkage following the initiation of this drug. The case involves a 68-year-old man diagnosed with small cell lung cancer and ectopic ACTH-producing Cushing syndrome. Initially, metyrapone was administered to manage hypercortisolism, but its effect proved insufficient. Subsequently, osilodrostat was initiated while gradually decreasing metyrapone, leading to full suppression of blood cortisol levels. With continued osilodrostat treatment, the adrenal glands reduced in size, suggesting the potential to reduce the osilodrostat dosage.

Prolonged adrenal insufficiency following discontinuation of osilodrostat treatment for intense hypercortisolism

The cases of 3 patients with Cushing's disease who developed long-term adrenal insufficiency after discontinuation of prolonged osilodrostat therapy were recently described for the first time. We report 2 additional cases of persistent prolonged adrenal insufficiency after discontinuation of osilodrostat treatment for intense hypercortisolism due to Cushing's disease and ectopic ACTH syndrome. In addition, we show for that adrenal insufficiency in these patients was associated with low/normal 11-deoxycortisol concentrations despite high plasma ACTH concentrations. These results suggest that CYP11B1 is not the only target of osilodrostat and that, in vivo, osilodrostat has other prolonged and strong inhibitory effect on adrenal steroidogenesis upstream of CYP11B1. Knowledge of this remnant effect is important for the care of patients with Cushing's syndrome treated with osilodrostat. Further studies are needed to clarify the frequency and the mechanisms of this remnant effect.

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.

Long-term efficacy and safety of osilodrostat in patients with Cushing's disease: results from the LINC 4 study extension

Objective

To evaluate the long-term efficacy and safety of osilodrostat in patients with Cushing's disease.

Methods

The multicenter, 48-week, Phase III LINC 4 clinical trial had an optional extension period that was initially intended to continue to week 96. Patients could continue in the extension until a managed-access program or alternative treatment became available locally, or until a protocol amendment was approved at their site that specified that patients should come for an end-of-treatment visit within 4 weeks or by week 96, whichever occurred first. Study outcomes assessed in the extension included: mean urinary free cortisol (mUFC) response rates; changes in mUFC, serum cortisol and late-night salivary cortisol (LNSC); changes in cardiovascular and metabolic-related parameters; blood pressure, waist circumference and weight; changes in physical manifestations of Cushing's disease; changes in patient-reported outcomes for health-related quality of life; changes in tumor volume; and adverse events. Results were analyzed descriptively; no formal statistical testing was performed.

Results

Of 60 patients who entered, 53 completed the extension, with 29 patients receiving osilodrostat for more than 96 weeks (median osilodrostat duration: 87.1 weeks). The proportion of patients with normalized mUFC observed in the core period was maintained throughout the extension. At their end-of-trial visit, 72.4% of patients had achieved normal mUFC. Substantial reductions in serum cortisol and LNSC were also observed. Improvements in most cardiovascular and metabolic-related parameters, as well as physical manifestations of Cushing's disease, observed in the core period were maintained or continued to improve in the extension. Osilodrostat was generally well tolerated; the safety profile was consistent with previous reports.

Conclusion

Osilodrostat provided long-term control of cortisol secretion that was associated with sustained improvements in clinical signs and physical manifestations of hypercortisolism. Osilodrostat is an effective long-term treatment for patients with Cushing's disease.

Clinical trial registration

ClinicalTrials.gov, identifier NCT02180217.

Successful Management of Cushing Syndrome From Ectopic ACTH Secretion in an Adolescent With Osilodrostat

A previously healthy 11-year-old male was found to have a mass in the pancreatic head after several months of abdominal pain and jaundice. Pathology was consistent with a World Health Organization grade 2 pancreatic neuroendocrine tumor. He developed refractory hypertension and was found to have Cushing syndrome from ectopic ACTH secretion, with oligometastatic liver disease. He underwent surgical resection of the pancreatic tumor and metastases. Postoperatively, his Cushing syndrome resolved, but it reemerged 1 year later in the setting of disease recurrence. He was not a candidate for bilateral adrenalectomy. Ketoconazole therapy was inadequate and he was started on metyrapone, lanreotide, cabergoline, and spironolactone. Although this regimen was well-tolerated, his Cushing syndrome recurred 4 months later as his metastatic disease burden increased. Osilodrostat was begun and the dose was gradually increased in response to his uncontrolled Cushing syndrome. Osilodrostat resulted in rapid improvement and eventual normalization of his urinary free cortisol at a dose of 18 mg twice daily. He had no adverse effects. This rare case highlights the successful off-label use of osilodrostat, a medication intended for refractory Cushing disease in adult patients, in a pediatric patient with Cushing syndrome caused by ectopic ACTH secretion.

COVID-19 infection in a patient with Cushing's disease on osilodrostat treatment

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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.

An evaluation of pharmacological options for Cushing's disease: what are the state-of-the-art options?

INTRODUCTION

Untreated Cushing's syndrome (CS) is associated with significant morbidity and mortality. Cortisol normalization is a key goal to treatment. Pituitary surgery remains the first-line approach for Cushing's disease, but sometimes it is impracticable, unsuccessful, or complicated by recurrence. Medical therapy has been historically considered a palliative. However, in the latest years, interest on this topic has grown due to both the availability of new drugs and the reevaluation of the old, commonly used drugs in clinical practice.

AREAS COVERED

In this article, we will discuss the current options and future directions of medical therapy for CS, aiming at fitting best patients' features. An extensive literature search regarding already approved and investigational principles was conducted (PubMed, ClinicalTrials.gov. Available drugs include inhibitors of ACTH secretion, steroidogenesis inhibitors, and glucocorticoid receptor antagonists; drugs acting at different levels can be also combined in uncontrolled patients.

EXPERT OPINION

Since there is still no standardized pharmacological approach and the superiority of one drug over another has not been established yet in the absence of comparative studies, each time clinicians' choices should be patient-tailored. Age, gender, tumor features, severity of hypercortisolism, comorbidities/complications, rapidity of action, side effects, drug-drug interactions, contraindications, availability, patients' preferences, and costs should be all considered.

Progression of a corticotroph tumour during durable medical therapy with osilodrostat in a patient with persistent Cushing's disease

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Efficacy and safety of osilodrostat in paraneoplastic Cushing's syndrome: a real-world multicenter study in France

CONTEXT

Prospective studies have demonstrated the efficacy of osilodrostat in Cushing's disease. No study has evaluated osilodrostat in a series of patients with paraneoplastic Cushing's syndrome/ectopic ACTH syndrome (PNCS/EAS).

OBJECTIVE

Evaluate in France the real-world efficacy and safety of osilodrostat in PNCS/EAS.

PATIENTS

33 patients with PNCS/EAS with intense/severe hypercortisolism.

METHODS

Retrospective multicenter real-world study. Patients received osilodrostat between May 2019 and March 2022. Median initial dose (range) 4 mg/day (1-60); maximum dose, 20 mg/day (4-100), first, under patient- then cohort- temporary authorizations and after marketing authorization. Regimens used: titration (n = 6), block and replace (n = 16), or titration followed by block and replace (n = 11).

RESULTS

In 11 patients receiving osilodrostat as first-line monotherapy, median 24h- urinary free cortisol (24h-UFC) decreased dramatically (from 26xULN [2.9-659] to 0.11xULN [0.08-14.9]; p < 0.001). In 9 of them, 24h-UFC normalization was achieved in 2 weeks (median). Thirteen additional patients were previously treated with classic steroidogenesis inhibitors but 10/13 were not controlled. In these patients, osilodrostat monotherapy, used in second line, induced a significantly decreased of 24h-UFC (from 2.6xULN [1.1-144] to 0.22xULN [0.12-0.66]; p < 0.01). Nine additional patients received osilodrostat in combination with another anticortisolic drug decreasing 24h-UFC from 11.8xULN (0.3-247) to 0.43xULN (0.33-2.4) (p < 0.01).In parallel, major clinical symptoms/comorbidities improved dramatically with improvement in blood pressure, hyperglycemia and hypokalemia, allowing the discontinuation or dose reduction of their treatments. Adrenal insufficiency (grade 3-4) was reported in 8/33 patients.

CONCLUSIONS

Osilodrostat is a rapidly efficient therapy for PNCS/EAS with severe/intense hypercortisolism. Osilodrostat was generally well tolerated; Adrenal insufficiency was the main side effect.

How best to monitor the specific side effects of medical treatments of Cushing's disease

The first-line treatment of Cushing's disease is transsphenoidal surgery. Medical treatment of Cushing's disease can be considered in several situations: as a presurgical treatment in patients with severe comorbidities, when surgery fails, or while waiting for the maximal efficacy of radiation techniques. Several modalities of medical treatment are possible, from adrenal-targeting drugs (steroidogenesis inhibitors) to pituitary-targeting drugs (somatostatin receptor ligand pasireotide or the dopamine agonist cabergoline), or even drugs that antagonize the glucocorticoid receptor (mifepristone). Given the morbidities associated with hypercortisolism, and the fact that medical treatment can be delivered on a long-term basis, it is important to obtain eucortisolism and to monitor the drug effectively. The efficacy of these drugs will not be detailed in this review, nor their roles in the therapeutic algorithm of Cushing's disease. This review will rather focus specifically on adverse events associated with these drugs (ketoconazole, levoketoconazole, metyrapone, osilodrostat, pasireotide, cabergoline and mifepristone), and the way in which to monitor and treat them, based on retrospective studies and the most recently published prospective studies.

Randomized Trial of Osilodrostat for the Treatment of Cushing Disease

CONTEXT

Cushing disease, a chronic hypercortisolism disorder, is associated with considerable morbidity and mortality. Normalizing cortisol production is the primary treatment goal.

OBJECTIVE

We aimed to evaluate the safety and efficacy of osilodrostat, a potent, orally available 11βhydroxylase inhibitor, compared with placebo in patients with Cushing disease.

METHODS

LINC 4 was a phase III, multicenter trial comprising an initial 12-week, randomized, double-blind, placebo-controlled (osilodrostat:placebo, 2:1) period followed by a 36-week, open-label treatment period (NCT02697734). Adult patients (aged 18-75 years) with confirmed Cushing disease and mean urinary free cortisol (mUFC) excretion ≥ 1.3 times the upper limit of normal (ULN) were eligible. The primary endpoint was the proportion of randomized patients with mUFC ≤ ULN at week 12. The key secondary endpoint was the proportion achieving mUFC ≤ ULN at week 36 (after 24 weeks' open-label osilodrostat).

RESULTS

Seventy-three patients (median age, 39 years [range, 19-67]; mean/median mUFC, 3.1 × ULN/2.5 × ULN) received randomized treatment with osilodrostat (n = 48) or placebo (n = 25). At week 12, significantly more osilodrostat (77%) than placebo (8%) patients achieved mUFC ≤ ULN (odds ratio 43.4; 95% CI 7.1, 343.2; P < 0.0001). Response was maintained at week 36, when 81% (95% CI 69.9, 89.1) of all patients achieved mUFC ≤ ULN. The most common adverse events during the placebo-controlled period (osilodrostat vs placebo) were decreased appetite (37.5% vs 16.0%), arthralgia (35.4% vs 8.0%), and nausea (31.3% vs 12.0%).

CONCLUSION

Osilodrostat rapidly normalized mUFC excretion in most patients with Cushing disease and maintained this effect throughout the study. The safety profile was favorable.

Osilodrostat - an emerging drug for the medical management of Cushing's disease

Cushing's disease (CD) is a rare endocrine disorder characterized by the overproduction of adrenocorticotropic hormone (ACTH) by pituitary adenoma followed by hypercortisolaemia with severe complications. Although transsphenoidal resection of the defined pituitary adenoma has been the treatment of choice for the past decades, it does not always result in long-term remission - 10-30% of cases show ineffective surgical treatment or tumour recurrence even after initial success. Pharmacological therapies for cortisol reduction are often required for those who either cannot undergo pituitary surgery or when the surgery has failed, and patients still present with the persistent disease. Osilodrostat is a potent oral steroidogenesis inhibitor that has lately been shown as an effective adjuvant therapy in the management of patients with CD. In this article, we review the recent reports on the efficacy and safety of osilodrostat in clinical settings.

Metyrapone Versus Osilodrostat in the Short-Term Therapy of Endogenous Cushing's Syndrome: Results From a Single Center Cohort Study

BACKGROUND

Although surgery is considered the first-line treatment for patients with endogenous Cushing's syndrome (CS), medical therapy is often required to control severe hypercortisolism. Metyrapone and osilodrostat are both steroidogenic inhibitors targeting the 11β-hydroxylase, however, their therapeutic effectiveness has not yet been directly compared. This study aimed to evaluate metyrapone and osilodrostat in the short-term therapy of CS.

METHODS

Retrospective analysis of patients with endogenous CS treated with metyrapone or osilodrostat as monotherapy for at least 4 weeks. Main outcome measures were serum cortisol and 24h urinary free cortisol (UFC) at baseline (T0) and after 2 (T1), 4 (T2), and 12 weeks (T3) of therapy.

RESULTS

16 patients with endogenous CS were identified (pituitary n=7, adrenal n=4, ectopic CS n=5). Each 8 patients were treated with metyrapone and osilodrostat. Despite heterogeneity, both groups showed comparable mean UFC levels at T0 (metyrapone: 758 µg/24h vs osilodrostat: 817 µg/24h; p=0.93). From T0 to T1, the decrease of UFC was less pronounced under metyrapone than osilodrostat (-21.3% vs -68.4%; median daily drug dose: 1000 mg vs 4 mg). This tendency persisted at T2 (-37.3% vs -50.1%; median drug dose: 1250 mg vs 6 mg) while at T3 a decrease in UFC from T0 was more pronounced in the metyrapone group (-71.5% vs -51.5%; median dose 1250 mg vs 7 mg). Under osilodrostat, a QTc-interval prolongation was identified at T3 (mean 432 ms vs 455 ms). From T0 to T2, the number of antihypertensive drugs remained comparable under metyrapone and decreased under osilodrostat (n= -0.3 vs n= -1.0).

CONCLUSION

Although both drugs show comparable therapeutic efficacy, osilodrostat seems to reduce cortisol levels and to control blood pressure faster.

Individualized medical treatment options in Cushing disease

Cushing disease (CD) is caused by a pituitary tumor which oversecretes adrenocorticotropic hormone (ACTH). It is a serious endocrine disease associated with increased mortality and impaired quality of life. The management of CD remains challenging. Although transsphenoidal surgery is the treatment of choice in most cases, in approximately half of CD patients, second or third-line treatment options are needed. Currently, new medical therapies are available which target adrenal steroidogenesis, pituitary somatostatin and dopamine receptors, and glucocorticoid receptors. Selection of which medication to use should be individualized and is determined by many factors including severity of the disease, possible side effects, patients preferences and local availability. The aim of this article is to describe currently available medical therapy to help clinicians individualize the treatment options in the context of recently updated Pituitary Society recommendations.

Osilodrostat: A Review of Recent Clinical Studies and Practical Recommendations for its Use in the Treatment of Cushing Disease

OBJECTIVE

Cushing disease (CD) is characterized by chronic hypercortisolism caused by an adrenocorticotropic hormone-secreting pituitary adenoma. Surgery remains the first-line treatment option; however, medical therapy is essential if surgery is contraindicated or fails to achieve remission or when recurrence occurs after surgical remission. Osilodrostat (Isturisa), a novel steroidogenic inhibitor, is now approved for the treatment of CD in the United States and Cushing syndrome in Europe. Herein, we review pharmacology and data on the efficacy, safety, and clinical use of osilodrostat and provide guidance on its use in treating patients with CD.

METHODS

We reviewed the literature and published clinical trial data of osilodrostat use in patients with Cushing syndrome. Detailed information related to the clinical assessment of osilodrostat use, potential drug-to-drug interactions, drug initiation, dose titration, and the monitoring of drug tolerability were discussed.

RESULTS

Clinical trial data demonstrated that osilodrostat, by virtue of inhibiting 11-β hydroxylase, potently and rapidly decreased the 24-hour urinary free cortisol levels and sustained these reductions, with improved glycemia, blood pressure, body weight, and quality of life as well as lessened depression. Osilodrostat may interact with certain drugs, resulting in QT prolongation, which requires careful assessment of concomitant medications and periodic monitoring using electrocardiogram, respectively. The common adverse effects include adrenal insufficiency, hypokalemia, edema, and hyperandrogenic symptoms, which can be minimized using a slower up-titration dosing regimen.

CONCLUSION

Osilodrostat is an effective, new treatment option for CD, with positive effects on cardiovascular and quality of life parameters as well as tolerable adverse effects. This article provides a review of the pharmacology of osilodrostat and offers practical recommendations on the use of osilodrostat to treat CD.

Approach to the Patient Treated with Steroidogenesis Inhibitors

Steroidogenesis inhibitors can be given to control the hypercortisolism of Cushing's syndrome in various situations: when surgery has been unsuccessful or not possible; in metastatic adrenocorticotropin hormone (ACTH) or cortisol-secreting tumors; when waiting for the maximal efficacy of radiation techniques; for rapid treatment of severe hypercortisolism in patients with occult ACTH-producing tumors; or as a presurgical treatment in patients with severe comorbidities. Whilst biochemical "control" can be achieved in more than 50% of cases, daily management of such drugs can be challenging. Indeed, with a "dose-titration" or a "block and replace" approach, defining eucortisolism is usually difficult, requiring the measurement of several biological markers. Moreover, each drug has its own side effects, which must be monitored closely. The aim of this "approach to the patient" is to shed light on the management of hypercortisolism with 4 steroidogenesis inhibitors (ketoconazole, levoketoconazole, metyrapone, osilodrostat) to help endocrinologists dealing with patients with Cushing's syndrome. Various points will be discussed, such as initial dose of treatment, dose schedule, monitoring of efficacy, and side effects of monotherapy. The combination of steroidogenesis inhibitors will also be discussed.

Osilodrostat for the treatment of Cushing's disease

INTRODUCTION

The treatment of Cushing's disease (CD) has been advanced well with the introduction of treatment options like transsphenoidal surgery, radiosurgery, bilateral adrenalectomy, and various classes of medication; however, many patients still fail to achieve disease remission. Osilodrostat, an orally bioavailable adrenal steroidogenesis inhibitor, was approved in the USA and EU in 2020 for the treatment of CD.

AREAS COVERED

This review provides an overview of Cushing's disease and the newly FDA approved 11β-hydroxylase inhibitor, osilodrostat, for CD with a focus on pharmacodynamics, pharmacokinetics, safety and efficacy data, and phase 2 and 3 clinical trials.

EXPERT OPINION

Osilodrostat has proven clinical efficacy and tolerability in phase 2 and 3 trials with CD patients who had an inadequate or reoccurring response to transsphenoidal surgery (TSS) and conventional first-line treatment. The phase 3 trial (LINC3) had 86% of the treatment group respond with normal urinary free cortisol (UFC) level compared to 29% in the placebo group (p < 0.001). Deemed as well-tolerated in all current pivotal trials, oral osilodrostat provides a noninvasive option for patients who cannot undergo surgery or patients who have reoccurring hypercortisolemia.

Adrenally Directed Medical Therapies for Cushing Syndrome

CONTEXT

Endogenous Cushing syndrome (CS) is characterized by excess cortisol secretion, which is driven by tumorous secretion of corticotropin in the majority of patients. Untreated, CS results in substantial morbidity and mortality. Tumor-directed surgery is generally the first-line therapy for CS. However, hypercortisolism may persist or recur postoperatively; in other cases, the underlying tumor may not be resectable or its location may not be known. Yet other patients may be acutely ill and require stabilization before definitive surgery. In all these cases, additional interventions are needed, including adrenally directed medical therapies.

EVIDENCE ACQUISITION

Electronic literature searches were performed to identify studies pertaining to adrenally acting agents used for CS. Data were abstracted and used to compile this review article.

EVIDENCE SYNTHESIS

Adrenally directed medical therapies inhibit one or several enzymes involved in adrenal steroidogenesis. Several adrenally acting medical therapies for CS are currently available, including ketoconazole, metyrapone, osilodrostat, mitotane, and etomidate. Additional agents are under investigation. Drugs differ with regards to details of their mechanism of action, time course of pharmacologic effect, safety and tolerability, potential for drug-drug interactions, and route of administration. All agents require careful dose titration and patient monitoring to ensure safety and effectiveness, while avoiding hypoadrenalism.

CONCLUSIONS

These medications have an important role in the management of CS, particularly among patients with persistent or recurrent hypercortisolism postoperatively or those who cannot undergo tumor-directed surgery. Use of these drugs mandates adequate patient instruction and close monitoring to ensure treatment goals are being met while untoward adverse effects are minimized.