Mifepristone Increases Thyroid Hormone Requirements in Patients With Central Hypothyroidism: A Multicenter Study

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.

Medications and Food Interfering with the Bioavailability of Levothyroxine: A Systematic Review

Purpose

Levothyroxine is a common prescribed drug. Many medications and food, however, can interfere with its bioavailability. The aim of this review was to summarize the medications, food and beverages that interact with levothyroxine and to assess their effects, mechanisms and treatments.

Methods

A systematic review on interfering substances that interact with levothyroxine was performed. Web of Science, Embase, PubMed, the Cochrane library, grey literature from other sources and the lists of references were searched for human studies comparing the levothyroxine efficacy with and without interfering substances. The patient characteristics, drug classes, effects and mechanism were extracted. The NHLBI study quality assessment tools and the JBI critical appraisal checklist were used to assess the quality of included studies.

Results

A total of 107 articles with 128 studies were included. Drugs interactions were revealed in calcium and iron supplements, proton pump inhibitors, bile acid sequestrants, phosphate binders, sex hormones, anticonvulsants and other drugs. Some food and beverage could also induce malabsorption. Proposed mechanisms included direct complexing, alkalization, alteration of serum thyroxine-binding globulin levels and acceleration of levothyroxine catabolism via deiodination. Dose adjustment, administration separation and discontinuation of interfering substances can eliminate the interactions. Liquid solutions and soft-gel capsules could eliminate the malabsorption due to chelation and alkalization. The qualities of most included studies were moderate.

Conclusion

Lots of medications and food can impair the bioavailability of levothyroxine. Clinicians, patients and pharmaceutical companies should be aware of the possible interactions. Further well-designed studies are needed to provide more solid evidence on treatment and mechanisms.

Advances in Molecular Pathophysiology and Targeted Therapy for Cushing's Disease

Cushing's disease is caused by autonomous secretion of adrenocorticotropic hormone (ACTH) from corticotroph pituitary neuroendocrine tumors. As a result, excess cortisol production leads to the overt manifestation of the clinical features of Cushing's syndrome. Severe complications have been reported in patients with Cushing's disease, including hypertension, menstrual disorders, hyperglycemia, osteoporosis, atherosclerosis, infections, and mental disorders. Cushing's disease presents with a variety of clinical features, ranging from overt to subtle. In this review, we explain recent advances in molecular insights and targeted therapy for Cushing's disease. The pathophysiological characteristics of hormone production and pituitary tumor cells are also explained. Therapies to treat the tumor growth in the pituitary gland and the autonomous hypersecretion of ACTH are discussed. Drugs that target corticotroph pituitary neuroendocrine tumors have been effective, including cabergoline, a dopamine receptor type 2 agonist, and pasireotide, a multi-receptor-targeted somatostatin analog. Some of the drugs that target adrenal hormones have shown potential therapeutic benefits. Advances in potential novel therapies for Cushing's disease are also introduced.

Mifepristone-Induced Hypothyroidism

Medications are known to affect the thyroid physiology and are a known cause of hypothyroidism. There is an ever-growing list of medications that affect the thyroid by 1 or more mechanisms. Mifepristone is presently used for the treatment of mild autonomous cortisol secretion (MACS). Hypothyroidism is not a known side effect of this medication. We present a 71-year-old woman with newly diagnosed impaired fasting glucose, dyslipidemia, and osteopenia presenting with a 3-year history of unintentional 15-pound weight gain (despite exercise and a good diet) and increased anxiety. Her physical examination was pertinent for mild lower extremity edema, easy bruising, and skin thinning. Workup revealed adrenocorticotropic hormone (ACTH)-independent MACS from bilateral micronodular hyperplasia of the adrenals. Since she was not a surgical candidate, medical management with mifepristone was chosen. While on mifepristone, she complained of excessive fatigue, a workup done revealed new-onset hypothyroidism. Given her symptoms and bloodwork, she was started on levothyroxine. After stopping mifepristone, she was biochemically and clinically euthyroid and was eventually off levothyroxine. The mechanism by which mifepristone induces hypothyroidism is unknown. Except for a multicenter case series suggesting that mifepristone increases thyroid hormone requirements in patients with central hypothyroidism, to the best of our knowledge, the literature on euthyroid patients developing hypothyroidism secondary to mifepristone is scarce. In conclusion, while the hypothyroidism seems reversible our case highlights the importance of getting baseline thyroid function tests (TFTs) and repeating them while on the medication. Treatment of hypothyroidism is based on symptoms and bloodwork.

Levothyroxine: Conventional and novel drug delivery formulations

Despite the fact that levothyroxine is one of the most prescribed medications in the world, its bioavailability has been reported to be impaired by many factors, including interfering drugs or foods and concomitant diseases, and persistent hypothyroidism with a high dose of levothyroxine is thus elicited. Persistent hypothyroidism can also be induced by noninterchangeability between formulations and poor compliance. To address these issues, some strategies have been developed. Novel formulations (liquid solutions and soft-gel capsules) have been designed to eliminate malabsorption. Some other delivery routes (injections, suppositories, sprays, and sublingual and transdermal administrations) are aimed at circumventing different difficulties in dosing, such as thyroid emergencies and dysphagia. Moreover, nanomaterials have been used to develop delivery systems for the sustained release of levothyroxine to improve patient compliance and reduce costs. Some delivery systems encapsulating nanoparticles show promising release profiles. In this review, we first summarize the medical conditions that interfere with the bioavailability of oral levothyroxine and discuss the underlying mechanisms and treatments. The efficacy of liquid solutions and soft-gel capsules are systematically evaluated. We further summarize the novel delivery routes for levothyroxine and their possible applications. Nanomaterials in the levothyroxine field are then discussed and compared based on their load and release profile. We hope the article provides novel insights into the drug delivery of levothyroxine.

Diagnostic and Prognostic Impact of Progesterone Receptor Immunohistochemistry: A Study Evaluating More Than 16,000 Tumors

Progesterone receptor (PR) is a member of the nuclear/steroid hormone receptor family of ligand-dependent transcription factors. It plays an important role in reproduction and mammary gland development and has various tissue-specific effects in nonreproductive organs. In diagnostic pathology, positive PR immunostaining is used to support a diagnosis of breast or gynecologic origin in a tumor. In this study, the expression of PR was analyzed by immunohistochemistry in 18,176 (interpretable: 16,445) samples from 147 different tumor types and subtypes in a tissue microarray format. PR immunostaining was detected in 57.4% of breast tumors, 28.6% of other gynecological tumors, and 1.8% of nongynecological and nonmammary tumors. Among the group of nongynecological and nonmammary tumors, particularly high rates of PR positivity were seen in neuroendocrine tumors (54.3%) and neuroendocrine carcinomas (35.7%) of the pancreas. A comparison with clinico-pathological parameters showed that reduced PR immunostaining was significantly associated with adverse histopathological and clinical features in breast carcinoma, endometrioid endometrial carcinoma, and pancreatic neuroendocrine tumors. In summary, our analysis of 147 different tumor types for PR immunostaining provides a ranking list of tumor entities according to their prevalence of PR positivity, helps to better understand the diagnostic utility of PR, and highlights the distinct PR positivity among neuroendocrine neoplasms of pancreatic origin.

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.

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.

Cushing's Syndrome Effects on the Thyroid

The most known effects of endogenous Cushing’s syndrome are the phenotypic changes and metabolic consequences. However, hypercortisolism can exert important effects on other endocrine axes. The hypothalamus–pituitary–thyroid axis activity can be impaired by the inappropriate cortisol secretion, which determinates the clinical and biochemical features of the “central hypothyroidism”. These findings have been confirmed by several clinical studies, which also showed that the cure of hypercortisolism can determine the recovery of normal hypothalamus–pituitary–thyroid axis activity. During active Cushing’s syndrome, the “immunological tolerance” guaranteed by the hypercortisolism can mask, in predisposed patients, the development of autoimmune thyroid diseases, which increases in prevalence after the resolution of hypercortisolism. However, the immunological mechanism is not the only factor that contributes to this phenomenon, which probably includes also deiodinase-impaired activity. Cushing’s syndrome can also have an indirect impact on thyroid function, considering that some drugs used for the medical control of hypercortisolism are associated with alterations in the thyroid function test. These considerations suggest the utility to check the thyroid function in Cushing’s syndrome patients, both during the active disease and after its remission.

Mifepristone as Bridge or Adjunct Therapy in the Management of Challenging Cushing Disease Cases

Establishing a definitive diagnosis of Cushing disease (CD), given its clinical and biochemical heterogeneity, initiating effective treatment to control the effects of hypercortisolism, and managing recurrence are challenging disease aspects to address. Mifepristone is a competitive glucocorticoid receptor antagonist that is approved in the US by the Food and Drug Administration to control hyperglycemia secondary to endogenous hypercortisolism (Cushing syndrome) in patients who have glucose intolerance or type 2 diabetes mellitus and have failed surgery or are not candidates for surgery. Herein, we describe 6 patients with CD who received mifepristone as adjunct/bridge therapy in the following clinical settings: to assess clinical benefits of treatment for suspected recurrent disease, to control hypercortisolism preoperatively for severe disease, to control hypercortisolism during the COVID-19 pandemic, and to provide adjunctive treatment to radiation therapy. The patients were treated at multiple medical practice settings. Mifepristone treatment in each of the described cases was associated with clinical improvements, including improvements in overall glycemia, hypertension, and weight loss. In addition, in one case where biochemical and radiological evidence of disease recurrence was uncertain, clinical improvement with mifepristone pointed toward likely disease recurrence. Adverse events associated with mifepristone reported in the 6 cases were consistent with those previously reported in the pivotal trial and included cortisol withdrawal symptoms, antiprogesterone effects (vaginal bleeding), hypothyroidism (treated with levothyroxine), and hypokalemia (treated with spironolactone). These cases show how mifepristone can potentially be utilized as a therapeutic trial in equivocal cases of CD recurrence; as a presurgical treatment strategy, particularly during the COVID-19 pandemic; and as bridge therapy, while awaiting the effects of radiation.

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.