Effectiveness of Medical Treatment of Cushing's Disease: A Systematic Review and Meta-Analysis

Medical treatment of functional pituitary adenomas, trials and tribulations

CONTEXT

Functioning pituitary adenomas (FPAs) include most frequently prolactinomas, somatotroph or corticotroph adenomas, while thyrotroph and gonadotroph adenomas are very rare. Despite their benign histological nature (aggressive tumors are rare and malignant ones exceptional), FPAs could cause significant morbidity and increased mortality due to complications associated with hormonal excess syndromes and/or mass effect leading to compression of adjacent structures. This mini review will focus on the increasing role of medical therapy in the multimodal treatment, which also includes transsphenoidal surgery (TSS) and radiotherapy.

EVIDENCE SYNTHESIS

Most patients with prolactinomas are treated only with medications, but surgery could be considered for some patients in a specialized pituitary center, if higher chances of cure. Dopamine agonists, especially cabergoline, are efficient in reducing tumor size and normalizing prolactin. TSS is the first-line treatment for all other FPAs, but most patients require complex adjuvant treatment, including a combination of therapeutic approaches. Medical therapy is the cornerstone of treatment in all patients after unsuccessful surgery or when surgery cannot be offered and includes somatostatin receptor ligands and dopamine agonists (almost all FPAs), growth hormone receptor antagonists (acromegaly), adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers (Cushing's disease). Novel medical treatments, especially for acromegaly and Cushing's disease are under research.

CONCLUSIONS

An enlarged panel of effective drugs available with increased knowledge of predictive factors for response and/or adverse effects will enhance the possibility to offer a more individualized treatment. This would not only improve disease control and prognosis, but also quality of life.

Current and Emerging Pharmacological Therapies for Cushing's Disease

Cushing's Disease (CD), hypercortisolism due to pituitary ACTH secreting neuroendocrine neoplasm, is associated with increased morbidity and, if untreated, mortality in about half of the affected individuals. Consequently, the timely initiation of effective treatment is mandatory. Neurosurgery is the first line and the only potentially curative treatment; however, 30% of patients will have persistent disease post-surgery. Furthermore, a small percentage of those initially controlled will develop hypercortisolism during long-term follow- up. Therefore, patients with persistent or recurrent disease, as well as those considered non-eligible for surgery, will need a second-line therapeutic approach, i.e., pharmacotherapy. Radiation therapy is reserved as a third-line therapeutic option due to its slower onset of action and its unfavorable profile regarding complications. During the past few years, the understanding of molecular mechanisms implicated in the physiology of the hypothalamus-pituitary-adrenal axis has evolved, and new therapeutic targets for CD have emerged. In the present review, currently available treatments, compounds currently tested in ongoing clinical trials, and interesting, potentially new targets emerging from unraveling molecular mechanisms involved in the pathophysiology of Cushing's disease are discussed.

Cushing's syndrome

Endogenous Cushing's syndrome results from excess glucocorticoid secretion, which leads to a myriad of clinical manifestations, comorbidities, and increased mortality despite treatment. Molecular mechanisms and genetic alterations associated with different causes of Cushing's syndrome have been described in the last decade. Imaging modalities and biochemical testing have evolved; however, both the diagnosis and management of Cushing's syndrome remain challenging. Surgery is the preferred treatment for all causes, but medical therapy has markedly advanced, with new drug options becoming available. Nevertheless, several comorbidities remain even after patient remission, which can affect quality of life. Accurate and timely diagnosis and treatment are essential for mitigating chronic complications of excess glucocorticoids and improving patient quality of life. In this Seminar, we aim to update several important aspects of diagnosis, complications, and treatment of endogenous Cushing's syndrome of all causes.

An individualized approach to the management of Cushing disease

Cushing disease caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary corticotroph adenoma leads to hypercortisolaemia with high mortality due to metabolic, cardiovascular, immunological, neurocognitive, haematological and infectious conditions. The disorder is challenging to diagnose because of its common and heterogenous presenting features and the biochemical pitfalls of testing levels of hormones in the hypothalamic-pituitary-adrenal axis. Several late-night salivary cortisol and 24-h urinary free cortisol tests are usually required as well as serum levels of cortisol after a dexamethasone suppression test. MRI might only identify an adenoma in 60-75% of patients and many adenomas are small. Therefore, inferior petrosal sinus sampling remains the gold standard for confirmation of ACTH secretion from a pituitary source. Initial treatment is usually transsphenoidal adenoma resection, but preoperative medical therapy is increasingly being used in some countries and regions. Other management approaches are required if Cushing disease persists or recurs following surgery, including medications to modulate ACTH or block cortisol secretion or actions, pituitary radiation, and/or bilateral adrenalectomy. All patients require lifelong surveillance for persistent comorbidities, clinical and biochemical recurrence, and treatment-related adverse effects (including development of treatment-associated hypopituitarism). In this Review, we discuss challenges in the management of Cushing disease in adults and provide information to guide clinicians when planning an integrated and individualized approach for each patient.

Evaluating the burden of endogenous Cushing's syndrome using a web-based questionnaire and validated patient-reported outcome measures

INTRODUCTION

Endogenous Cushing's syndrome (CS) is a rare endocrine condition caused by chronic oversecretion of cortisol, resulting in a diverse constellation of symptoms. This study examined the ongoing burden of illness (BOI), from the first appearance of symptoms through treatment, which is currently not well evaluated.

METHODS

A quantitative, cross-sectional, web-enabled survey including 5 validated patient reported outcomes (PRO) measures was conducted in patients with CS who had been diagnosed ≥ 6 months prior and who had received ≥ 1 treatment for their endogenous CS at the time of the survey.

RESULTS

Fifty-five patients participated in this study; 85% were women. The mean age was 43.4 ± 12.3 years (± standard deviation, SD). On average, respondents reported a 10-year gap between the first occurrence of symptoms and diagnosis; 80% underwent surgical treatment for CS. Respondents experienced symptoms on 16 days in a typical month, and their health-related quality of life was moderately impacted based on the CushingQoL score. Weight gain, muscle fatigue, and weakness were the most common symptoms and 69% percent of patients reported moderate or severe fatigue using the Brief Fatigue Inventory. Following treatment, the occurrence of most symptoms declined over time, although anxiety and pain did not significantly decrease. Overall, 38% of participants reported an annual average of 25 missed workdays due to CS symptoms.

CONCLUSIONS

These results demonstrate a BOI in CS despite ongoing treatment and illustrate the need for interventions to address persistent symptoms, particularly weight gain, pain, and anxiety.

Ketoconazole as second-line treatment for Cushing's disease after transsphenoidal surgery: systematic review and meta-analysis

Introduction

The first-line treatment for Cushing's disease is transsphenoidal surgery for pituitary tumor resection. Ketoconazole has been used as a second-line drug despite limited data on its safety and efficacy for this purpose. The objective of this meta-analysis was to analyze hypercortisolism control in patients who used ketoconazole as a second-line treatment after transsphenoidal surgery, in addition to other clinical and laboratory criteria that could be related to therapeutic response.

Methods

We searched for articles that evaluated ketoconazole use in Cushing's disease after transsphenoidal surgery. The search strategies were applied to MEDLINE, EMBASE, and SciELO. Independent reviewers assessed study eligibility and quality and extracted data on hypercortisolism control and related variables such as therapeutic dose, time, and urinary cortisol levels.

Results

After applying the exclusion criteria, 10 articles (one prospective and nine retrospective studies, totaling 270 patients) were included for complete data analysis. We found no publication bias regarding reported biochemical control or no biochemical control (p = 0.06 and p = 0.42 respectively). Of 270 patients, biochemical control of hypercortisolism occurred in 151 (63%, 95% CI 50-74%) and no biochemical control occurred in 61 (20%, 95% CI 10-35%). According to the meta-regression, neither the final dose, treatment duration, nor initial serum cortisol levels were associated with biochemical control of hypercortisolism.

Conclusion

Ketoconazole can be considered a safe and efficacious option for Cushing's disease treatment after pituitary surgery.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#searchadvanced, (CRD42022308041).

Unmet needs on the current medical management of Cushing's syndrome: results from a Delphi panel of Italian endocrinologists

BACKGROUND

Cushing's syndrome (CS) is a rare clinical condition caused by excessive cortisol secretion from adrenal glands. CS is associated with increased mortality and morbidity; therefore, a prompt diagnosis and an effective therapeutic approach are strongly necessary to improve the patient's clinical management. The first-line treatment for CS is surgery, while medical treatment has historically played a minor role. However, thanks to the availability of novel compounds, the possibility of improving hypercortisolism control using different drug combinations emerged.

PURPOSE

No absolute recommendations are available to guide the therapeutic choice for patients with CS and, consequently, the awareness of unmet needs in CS management is growing. Although new data from clinical trials are needed to better define the most appropriate management of CS, an expert consensus approach can help define unmet needs and optimize the current CS management and treatment.

METHODS

Twenty-seven endocrinologists from 12 Italian regions, working among the main Italian referral centers for hospital endocrinology where they take care of CS patients, were involved in a consensus process and used the Delphi method to reach an agreement on 24 statements about managing CS patients.

RESULTS

In total, 18 statements reached a consensus. Some relevant unmet needs in the management of CS were reported, mainly related to the lack of a pharmacological treatment successful for the majority of patients.

CONCLUSION

While acknowledging the difficulty in achieving complete disease control, a significant change in CS management requires the availability of medical treatment with improved efficacy and safety over available therapeutic options at the time of the current study.

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.

Medical treatment of Cushing's disease with concurrent diabetes mellitus

Cushing's disease (CD) is a severe endocrine disorder characterized by chronic hypercortisolaemia secondary to an overproduction of adrenocorticotropic hormone (ACTH) by a pituitary adenoma. Cortisol excess impairs normal glucose homeostasis through many pathophysiological mechanisms. The varying degrees of glucose intolerance, including impaired fasting glucose, impaired glucose tolerance, and Diabetes Mellitus (DM) are commonly observed in patients with CD and contribute to significant morbidity and mortality. Although definitive surgical treatment of ACTH-secreting tumors remains the most effective therapy to control both cortisol levels and glucose metabolism, nearly one-third of patients present with persistent or recurrent disease and require additional treatments. In recent years, several medical therapies demonstrated prominent clinical efficacy in the management of patients with CD for whom surgery was non-curative or for those who are ineligible to undergo surgical treatment. Cortisol-lowering medications may have different effects on glucose metabolism, partially independent of their role in normalizing hypercortisolaemia. The expanding therapeutic landscape offers new opportunities for the tailored therapy of patients with CD who present with glucose intolerance or DM, however, additional clinical studies are needed to determine the optimal management strategies. In this article, we discuss the pathophysiology of impaired glucose metabolism caused by cortisol excess and review the clinical efficacy of medical therapies of CD, with particular emphasis on their effects on glucose homeostasis.

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.

Osilodrostat-induced adrenal insufficiency in a patient with Cushing's disease

Cushing's disease is a rare condition caused by a benign pituitary tumor underlying adrenocorticotropic hormone excess. Medical treatment is implemented when surgical resection is not curative. We present a case of Cushing's disease with recurrence of macroadenoma who developed iatrogenic adrenal insufficiency in the setting of Osilodrostat treatment.

Levoketoconazole

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are available online to subscribers. Monographs can be customized to meet the needs of a facility. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, contact Wolters Kluwer customer service at 866-397-3433.

Pasireotide-Induced Shrinkage in GH and ACTH Secreting Pituitary Adenoma: A Systematic Review and Meta-Analysis

INTRODUCTION

Pasireotide (PAS) is a novel somatostatin receptor ligands (SRL), used in controlling hormonal hypersecretion in both acromegaly and Cushing's Disease (CD). In previous studies and meta-analysis, first-generation SRLs were reported to be able to induce significant tumor shrinkage only in somatotroph adenomas. This systematic review and meta-analysis aim to summarize the effect of PAS on the shrinkage of the pituitary adenomas in patients with acromegaly or CD.

MATERIALS AND METHODS

We searched the Medline database for original studies in patients with acromegaly or CD receiving PAS as monotherapy, that assessed the proportion of significant tumor shrinkage in their series. After data extraction and analysis, a random-effect model was used to estimate pooled effects. Quality assessment was performed with a modified Joanna Briggs's Institute tool and the risk of publication bias was addressed through Egger's regression and the three-parameter selection model.

RESULTS

The electronic search identified 179 and 122 articles respectively for acromegaly and CD. After study selection, six studies considering patients with acromegaly and three with CD fulfilled the eligibility criteria. Overall, 37.7% (95%CI: [18.7%; 61.5%]) of acromegalic patients and 41.2% (95%CI: [22.9%; 62.3%]) of CD patients achieved significant tumor shrinkage. We identified high heterogeneity, especially in acromegaly (I² of 90% for acromegaly and 47% for CD), according to the low number of studies included.

DISCUSSION

PAS treatment is effective in reducing tumor size, especially in acromegalic patients. This result strengthens the role of PAS treatment in pituitary adenomas, particularly in those with an invasive behavior, with progressive growth and/or extrasellar extension, with a low likelihood of surgical gross-total removal, or with large postoperative residual tissue.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022328152, identifier CRD42022328152.

Evaluation of ketoconazole as a treatment for Cushing's disease in a retrospective cohort

OBJECTIVE

The first-line treatment for Cushing's disease is transsphenoidal surgery, after which the rates of remission are 60 to 80%, with long-term recurrence of 20 to 30%, even in those with real initial remission. Drug therapies are indicated for patients without initial remission or with surgical contraindications or recurrence, and ketoconazole is one of the main available therapies. The objective of this study was to evaluate the safety profile of and the treatment response to ketoconazole in Cushing's disease patients followed up at the endocrinology outpatient clinic of a Brazilian university hospital.

PATIENTS AND METHODS

This was a retrospective cohort of Cushing's disease patients with active hypercortisolism who used ketoconazole at any stage of follow-up. Patients who were followed up for less than 7 days, who did not adhere to treatment, or who were lost to follow-up were excluded.

RESULTS

Of the 172 Cushing's disease patients who were followed up between 2004 and 2020, 38 received ketoconazole. However, complete data was only available for 33 of these patients. Of these, 26 (78%) underwent transsphenoidal surgery prior to using ketoconazole, five of whom (15%) had also undergone radiotherapy; seven used ketoconazole as a primary treatment. Ketoconazole use ranged from 14 days to 14.5 years. A total of 22 patients had a complete response (66%), three patients had a partial response (9%), and eight patients had no response to treatment (24%), including those who underwent radiotherapy while using ketoconazole. Patients whose hypercortisolism was controlled or partially controlled with ketoconazole had lower baseline 24-h urinary free cortisol levels than the uncontrolled group [times above the upper limit of normal: 0.62 (SD, 0.41) vs. 5.3 (SD, 8.21); p < 0.005, respectively] in addition to more frequent previous transsphenoidal surgery (p < 0.04). The prevalence of uncontrolled patients remained stable over time (approximately 30%) despite ketoconazole dose adjustments or association with other drugs, which had no significant effect. One patient received adjuvant cabergoline from the beginning of the follow-up, and it was prescribed to nine others due to clinical non-response to ketoconazole alone. Ten patients (30%) reported mild adverse effects, such as nausea, vomiting, dizziness, and loss of appetite. Only four patients had serious adverse effects that warranted discontinuation. There were 20 confirmed episodes of hypokalemia among 10/33 patients (30%).

CONCLUSION

Ketoconazole effectively controlled hypercortisolism in 66% of Cushing's disease patients, being a relatively safe drug for those without remission after transsphenoidal surgery or whose symptoms must be controlled until a new definitive therapy is carried out. Hypokalemia is a frequent metabolic effect not yet described in other series, which should be monitored during treatment.