Effect of cabergoline treatment on Cushing's disease caused by aberrant adrenocorticotropin-secreting macroadenoma

Neurochemical Anatomy of Cushing's Syndrome

The neurochemical anatomy underlying Cushing's syndrome is examined for regional brain metabolism as well as neurotransmitter levels and receptor binding of biogenic amines and amino acids. Preliminary studies generally indicate that glucose uptake, blood flow, and activation on fMRI scans decreased in neocortical areas and increased in subcortical areas of patients with Cushing's syndrome or disease. Glucocorticoid-mediated increases in hippocampal metabolism occurred despite in vitro evidence of glucocorticoid-induced decreases in glucose uptake or consumption, indicating that in vivo increases are the result of indirect, compensatory, or preliminary responses. In animal studies, glucocorticoid administration decreased 5HT levels and 5HT1A receptor binding in several brain regions while adrenalectomy increased such binding. Region-specific effects were also obtained in regard to the dopaminergic system, with predominant actions of glucocorticoid-induced potentiation of reuptake blockers and releasing agents. More in-depth neuroanatomical analyses are warranted of these and amino acid-related neurotransmission.

The dopaminergic control of Cushing's syndrome

Cushing's Syndrome (CS), or chronic endogenous hypercortisolism, is a rare and serious disease due to corticotroph pituitary (Cushing's disease, CD) and extra-pituitary (ectopic CS) tumours overproducing ACTH, or cortisol-secreting adrenal tumours or lesions (adrenal CS). The first-line treatment for CS is represented by the surgical removal of the responsible tumour, but surgery might be unfeasible or ineffective and medical treatment can be required in a relevant percentage of patients with CS, especially CD and ectopic CS. Corticotroph pituitary and extra-pituitary tumours, as well as adrenal tumours and lesions responsible for CS express dopamine receptors (DRs), which have been found to mediate inhibition of hormone secretion and/or cell proliferation in experimental setting, suggesting that dopaminergic system, particularly DRs, might represent a target for the treatment of CS. Dopamine agonists (DAs), particularly cabergoline (CAB), are currently used as off-label treatment for CD, the most common form of CS, demonstrating efficacy in controlling hormone secretion and tumour growth in a relevant number of cases, with the improvement of clinical picture, and displaying good safety profile. Therefore, CAB may be considered a reasonable alternative treatment for persistent or recurrent CD after pituitary surgery failure, but occasionally also before pituitary surgery, as adjuvant treatment, or even instead of pituitary surgery as first-line treatment in case of surgery contraindications or refusal. A certain beneficial effect of CAB has been also reported in ectopic CS. However, the role of DAs in the clinical management of the different types of CS requires further evaluations.

Targeting Aggressive Pituitary Adenomas at the Molecular Level-A Review

Pituitary adenomas (PAs) are mostly benign endocrine tumors that can be treated by resection or medication. However, up to 10% of PAs show an aggressive behavior with invasion of adjacent tissue, rapid proliferation, or recurrence. Here, we provide an overview of target structures in aggressive PAs and summarize current clinical trials including, but not limited to, PAs. Mainly, drug targets in PAs are based on general features of tumor cells such as immune checkpoints, so that programmed cell death 1 (ligand 1) (PD-1/PD-L1) targeting may bear potential to cure aggressive PAs. In addition, epidermal growth factor receptor (EGFR), mammalian target of rapamycin (mTOR), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and their downstream pathways are triggered in PAs, thereby modulating tumor cell proliferation, migration and/or tumor angiogenesis. Temozolomide (TMZ) can be an effective treatment of aggressive PAs. Combination of TMZ with 5-Fluorouracil (5-FU) or with radiotherapy could strengthen the therapeutic effects as compared to TMZ alone. Dopamine agonists (DAs) are the first line treatment for prolactinomas. Dopamine receptors are also expressed in other subtypes of PAs which renders DAs potentially suitable to treat other subtypes of PAs. Furthermore, targeting the invasive behavior of PAs could improve therapy. In this regard, human matrix metalloproteinase (MMP) family members and estrogens receptors (ERs) are highly expressed in aggressive PAs, and numerous studies demonstrated the role of these proteins to modulate invasiveness of PAs. This leaves a number of treatment options for aggressive PAs as reviewed here.

A review of Cushing's disease treatment by the Department of Neuroendocrinology of the Brazilian Society of Endocrinology and Metabolism

The treatment objectives for a patient with Cushing's disease (CD) are remission of hypercortisolism, adequate management of co-morbidities, restoration of the hypothalamic-pituitary-adrenal axis, preservation of fertility and pituitary function, and improvement of visual defects in cases of macroadenomas with suprasellar extension. Transsphenoidal pituitary surgery is the main treatment option for the majority of cases, even in macroadenomas with low probability of remission. In cases of surgical failure, another subsequent pituitary surgery might be indicated in cases with persistent tumor imaging at post surgical magnetic resonance imaging (MRI) and/or pathology analysis of adrenocorticotropic hormone-positive (ACTH+) positive pituitary adenoma in the first procedure. Medical treatment, radiotherapy and adrenalectomy are the other options when transsphenoidal pituitary surgery fails. There are several options of medical treatment, although cabergoline and ketoconazole are the most commonly used alone or in combination. Novel treatments are also addressed in this review. Different therapeutic approaches are frequently needed on an individual basis, both before and, particularly, after surgery, and they should be individualized. The objective of the present review is to provide the necessary information to achieve a more effective treatment for CD. It is recommended that patients with CD be followed at tertiary care centers with experience in treating this condition.

An unusual case of Cushing's syndrome due to bihormonal ACTH-prolactin secreting pituitary macroadenoma with rapid response to cabergoline

A 23-year-old man presenting with florid Cushing's syndrome was found to have high plasma ACTH and very high serum prolactin. Pituitary MRI showed a large invasive macroadenoma. Low-dose cabergoline promptly suppressed both ACTH and prolactin levels within 2 weeks, with unexpected clinical and biochemical hypocortisolism requiring hydrocortisone replacement. Secondary hypogonadism was reversed. Clinical and biochemical remission of his Cushing's syndrome together with significant shrinkage of his macroadenoma has been maintained for 1 year on cabergoline 0.5 mg twice weekly. Reduction in pituitary tumour volume and brisk fall in serum prolactin in response to low-dose cabergoline is regularly observed in patients with macroprolactinomas, but the concurrent fall in the plasma ACTH level and hypocortisolism was a pleasant surprise. We assume that he most likely has a single bihormonal adenoma that is enriched with dopamine-2 receptors.

Limited value of cabergoline in Cushing's disease: a prospective study of a 6-week treatment in 20 patients

CONTEXT AND OBJECTIVE

The role of cabergoline in Cushing's disease (CD) remains controversial. The experience is limited to case reports and few open studies that report the effects determined after ≥1 month of treatment. In prolactinomas and dopamine-responsive GH-secreting tumours, effects of cabergoline are seen within days or weeks. Here, we searched for short-term effects of cabergoline in CD.

DESIGN

Twenty patients (19 naïve and one recurrent) were included in a prospective study. Cabergoline was administered in increasing doses of 0.5-5 mg/week over 6 weeks.

METHODS

Urinary free cortisol (UFC) 24 h, morning cortisol and ACTH, and salivary cortisol at 0800, 1600 and 2300 h were determined once weekly throughout. Diurnal curves (six samples) of serum cortisol were measured at start and end.

RESULTS

At study end, the median cabergoline dose was 5 mg, range 2.5-5 mg/week. The prolactin levels, markers of compliance, were suppressed in all patients. During the treatment, hypercortisolism varied, gradual and dose-dependent reductions were not seen. Five patients had a >50% decrease of UFC, three had a >50% rise of UFC. Salivary cortisol at 2300 h showed a congruent >50% change with UFC in two of the five cases with decreased UFC, and in one of the three cases with increased UFC. One patient with decreases in both UFC and 2300 h salivary cortisol also had a reduction in diurnal serum cortisol during the course of the study.

CONCLUSIONS

Cabergoline seems to be of little value in the management of CD. Only one patient had a response-like pattern. Given the known variability of disease activity in CD, this might represent a chance finding.

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.

Remission with cabergoline in adolescent boys with Cushing's disease

Cabergoline is a long-acting dopamine receptor agonist used for treatment of patients with uncured Cushing's disease (CD) and, as a first-line treatment, was used in only limited numbers of patients. This report presents two adolescent boys with CD who were treated with cabergoline. Two adolescent boys with clinical and laboratory findings of CD are presented. No pituitary adenoma was detected by radiological investigation in either patient. Adrenocorticotropic hormone (ACTH) hypersecretion and lateralization was found by inferior petrosal sinus sampling in both patients. The initial cabergoline dose was 1mg/week and was adjusted up to 1.5 mg/week in the second patient, based on his urinary free cortisol (UFC) level. The patients responded to cabergoline treatment with normal UFC levels on the 4th and 6th months of treatment. The boys reached complete remission at the end of the 17th and 24th months, respectively. Cabergoline is effective in the control of cortisol secretion and can be considered as a first-line treatment in cases of CD.

Efficacy of cabergoline in uncured (persistent or recurrent) Cushing disease after pituitary surgical treatment with or without radiotherapy

OBJECTIVE

To evaluate the efficacy of cabergoline therapy in patients with Cushing disease who remained uncured (had persistent or recurrent disease) after a pituitary surgical procedure with or without radiotherapy.

METHODS

We undertook a prospective, open-label, single-arm study, with short-term (5 months) and longterm (1 year) evaluations. In 20 patients with uncured Cushing disease, treatment was initiated with cabergoline at a dosage of 1 mg/wk, with a monthly increment of 1 mg, until midnight serum cortisol (MNSC) or low-dose dexamethasone suppression serum cortisol (LDSC) (or both) normalized or a maximal dosage of 5 mg/wk was reached.

RESULTS

Overall, 5 of 18 patients (28%) responded in terms of LDSC or MNSC (or both) at a mean dosage of 3.6 mg/wk (range, 2 to 5). When the response was defined with use of either LDSC or MNSC level as an isolated criterion, it was achieved in 4 of 16 patients (25%) and 3 of 18 patients (17%), respectively. Four patients were treated for 1 year, and the response was persistent in 2 and 3 patients on the basis of MNSC and LDSC levels, respectively. Lower baseline serum cortisol (basal, MNSC, and LDSC) values were predictive of a therapeutic response.

CONCLUSION

Cabergoline was an effective therapy in 28%, 25%, and 17% of patients with uncured Cushing disease in terms of LDSC or MNSC (or both), LDSC alone, and MNSC alone, respectively. Further studies are needed to address the persistence of the drug response and the effects on the dynamics of the hypothalamic-pituitary-adrenal axis.

Cabergoline monotherapy in the long-term treatment of Cushing's disease

BACKGROUND

Cabergoline is a long-acting dopamine receptor agonist used to treat prolactinomas. Identification of D(2) receptors in corticotroph tumors led to clinical trials of cabergoline therapy in limited cases of Nelson's syndrome, ectopic ACTH-secreting tumors, and recently Cushing's disease (CD).

OBJECTIVE

To evaluate the long-term efficacy of cabergoline monotherapy in patients with CD.

METHODS

Retrospective analysis of non-randomized clinical therapy with cabergoline in 30 patients with CD treated in academic centers of Buenos Aires and Montreal. Cabergoline was initiated at 0.5-1.0 mg/week and adjusted up to a maximal dose of 6 mg/week based on urinary free cortisol (UFC) levels. Complete response to cabergoline was defined as a sustained normalization of UFC with at least two normal values measured at 1-3 months interval; partial response was defined as a decrease of UFC to <125% of the upper limit of normal, and treatment failure as UFC ≥ 125% of it.

RESULTS

Within 3-6 months, complete response was achieved in 11 patients (36.6%) and partial response in 4 patients (13.3%). After long-term therapy, nine patients (30%) remain with a complete response after a mean of 37 months (range from 12 to 60 months) with a mean dose of 2.1 mg/week of cabergoline. Two patients escaped after 2 and 5 years of complete response, but one patient transiently renormalized UFC after an increase in cabergoline dosage. No long-term response was maintained in four initial partial responders.

CONCLUSIONS

Cabergoline monotherapy can provide an effective long-term medical therapy for selected patients with CD, but requires close follow-up for dose adjustments.

Treatment of Cushing disease: overview and recent findings

Endogenous Cushing syndrome is an endocrine disease caused by excessive secretion of adrenocorticotropin hormone in approximately 80% of cases, usually by a pituitary corticotroph adenoma (Cushing disease [CD]). It is a heterogeneous disorder requiring a multidisciplinary and individualized approach to patient management. The goals of treatment of CD include the reversal of clinical features, the normalization of biochemical changes with minimal morbidity, and long-term control without recurrence. Generally, the treatment of choice is the surgical removal of the pituitary tumor by transsphenoidal approach, performed by an experienced surgeon. Considering the high recurrence rate, other treatments should be considered. Second-line treatments include more radical surgery, radiation therapy, medical therapy, and bilateral adrenalectomy. Drug treatment has been targeted at the hypothalamic or pituitary level, at the adrenal gland, and also at the glucocorticoid receptor level. Frequently, medical therapy is performed before surgery to reduce the complications of the procedure, reducing the effects of severe hypercortisolism. Commonly, in patients in whom surgery has failed, medical management is often essential to reduce or normalize the hypercortisolemia, and should be attempted before bilateral adrenalectomy is considered. Medical therapy can be also useful in patients with CD while waiting for pituitary radiotherapy to take effect, which can take up to 10 years or more. So far, results of medical treatment of CD have not been particularly relevant; however, newer tools promise to change this scenario. The aim of this review is to analyze the results and experiences with old and new medical treatments of CD and to reevaluate medical therapies for complications of CD and hypopituitarism in patients with cured CD.

Effectiveness of cabergoline in monotherapy and combined with ketoconazole in the management of Cushing's disease

The expression of dopamine receptor subtypes has been reported in corticotroph adenomas, and this finding support the possibility for medical treatment of Cushing's disease (CD) with dopamine agonists when conventional treatment has failed. The aim of this study was to evaluate the effectiveness of cabergoline (at doses of up 3 mg/week), alone or combined with relatively low doses of ketoconazole (up to 400 mg/day), in 12 patients with CD unsuccessfully treated by transsphenoidal surgery. After 6 months of cabergoline therapy, normalization of 24 h urinary free cortisol (UFC) levels occurred in three patients (25%) at doses ranging from 2-3 mg/week, whereas reductions ranging from 15.0 to 48.4% were found in the remaining. The addition of ketonocazole to the nine patients without an adequate response to cabergoline was able to normalize UFC excretion in six patients (66.7%) at doses of 200 mg/day (three patients), 300 mg/day (two patients) and 400 mg/day (one patient). In the remaining patients UFC levels did not normalize but a significant reduction ranging from to 44.4 to 51.7% was achieved. In two of the six responsive patients to combination therapy, the weekly dose of cabergoline could be later reduced from 3 to 2 mg. Our findings demonstrated that cabergoline monotherapy was able to reverse hypercortisolism in 25% of patients with CD unsuccessfully treated by surgery. Moreover, the addition of relatively low doses of ketoconazole led to normalization of UFC in about two-thirds of patients not achieving a full response to cabergoline.

Growth suppression of mouse pituitary corticotroph tumor AtT20 cells by curcumin: a model for treating Cushing's disease

BACKGROUND

Pituitary corticotroph tumors secrete excess adrenocorticotrophic hormone (ACTH) resulting in Cushing's disease (CD). Standard treatment includes surgery and, if not successful, radiotherapy, both of which have undesirable side effects and frequent recurrence of the tumor. Pharmacotherapy using PPARgamma agonists, dopamine receptor agonists, retinoic acid or somatostatin analogs is still experimental. Curcumin, a commonly used food additive in South Asian cooking, has potent growth inhibitory effects on cell proliferation. Our laboratory recently demonstrated that curcumin inhibited growth and induced apoptosis in prolactin- and growth hormone-producing tumor cells. Subsequently, Schaaf et.al. confirmed our findings and also showed the in vivo effectiveness of curcumin to suppress pituitary tumorigenesis. However the molecular mechanism that mediate this effect of curcumin are still unknown.

PRINCIPAL FINDINGS

Using the mouse corticotroph tumor cells, AtT20 cells, we report that curcumin had a robust, irreversible inhibitory effect on cell proliferation and clonogenic property. The curcumin-induced growth inhibition was accompanied by decreased NFkappaB activity. Further, curcumin down-regulated the pro-survival protein Bcl-xL, depolarized the mitochondrial membrane, increased PARP cleavage, which led to apoptotic cell death. Finally, curcumin had a concentration-dependent suppressive effect on ACTH secretion from AtT20 cells.

CONCLUSION

The ability of curcumin to inhibit NFkappaB and induce apoptosis in pituitary corticotroph tumor cells leads us to propose developing it as a novel therapeutic agent for the treatment of CD.

Drugs in the medical treatment of Cushing's syndrome

Cushing's syndrome is a complex endocrine condition with potential serious complications if untreated or inadequately treated. Transsphenoidal surgery with resection of a pituitary adenoma is successful in 75 - 80% of patients, but approximately 20 - 25% show persistence of Cushing's, and a similar proportion may experience recurrence within 2 - 4 years post-op. When surgery fails, medical treatment can temporarily suppress excessive cortisol production and ameliorate its clinical manifestations while more definitive therapy becomes effective. We describe pharmacological approaches to the treatment of Cushing's syndrome. Drugs used to suppress cortisol secretion are mostly inhibitors of steroidogenesis. Ketoconazole, fluconazole aminoglutethimide, metyrapone, mitotane and etomidate are in that category. Ketoconazole is in current use while other drugs, although mostly available in the past, continue to have a potential role either alone or in combination. Drugs that suppress adrenocorticotropic hormone (ACTH) secretion are less popular as standard treatment and include cyproheptadine, valproic acid, cabergoline, somatostatin analogs, PPAR-gamma agonists, vasopressin antagonists. Some of these drugs have been tested in limited clinical trials but there is potential therapeutic benefit in analogs with better specificity for the class of receptors present in ACTH-secreting tumors. A third category of drugs is glucocorticoid receptor antagonists. Mifepristone is currently being tested in clinical trials in patients with persistent or recurrent Cushing's disease and in patients with metastatic adrenal cortical carcinoma or ectopic ACTH syndrome not amenable to surgery. We also review replacement therapy after surgery and non-specific drugs to treat complications in patients with severe hypercortisol. The review provides a complete survey of the drugs used in the medical treatment of Cushing's, and new advances in the development of pituitary-active drugs as well as receptor blockers of glucocorticoid action. It also provides avenues for exploration of new drugs active on somatostatin, dopamine and vasopressin receptors. There are effective pharmacological agents capable of chronically reversing biochemical and clinical manifestations of hypercortisolemia in Cushing's syndrome but new drugs are needed with action at the pituitary level.

Somatostatin and dopamine receptors as targets for medical treatment of Cushing's Syndrome

Somatostatin (SS) and dopamine (DA) receptors are widely expressed in neuroendocrine tumours that cause Cushing's Syndrome (CS). Increasing knowledge of specific subtype expression within these tumours and the ability to target these receptor subtypes with high-affinity compounds, has driven the search for new SS- or DA-based medical therapies for the various forms of CS. In Cushing's disease, corticotroph adenomas mainly express dopamine receptor subtype 2 (D(2)) and somatostatin receptor subtype 5 (sst(5)), whereas sst(2) is expressed at lower levels. Activation of these receptors can inhibit ACTH-release in primary cultured corticotroph adenomas and compounds that target either sst(5) (pasireotide, or SOM230) or D(2) (cabergoline) have shown significant efficacy in subsets of patients in recent clinical studies. Combination therapy, either by administration of both types of compounds separately or by treatment with novel somatostatin-dopamine chimeric molecules (e.g. BIM-23A760), appears to be a promising approach in this respect. In selected cases of Ectopic ACTH-producing Syndrome (EAS), the sst(2)-preferring compound octreotide is able to reduce cortisol levels effectively. A recent study showed that D(2) receptors are also significantly expressed in the majority of EAS and that cabergoline may decrease cortisol levels in subsets of these patients. In both normal adrenal tissue as well as in adrenal adenomas and carcinomas that cause CS, sst and DA receptor expression has been demonstrated. Although selected cases of adrenal CS may benefit from sst or DA-targeted treatment, its total contribution to the treatment of these patients is likely to be low as surgery is effective in most cases.

Pituitary-directed medical treatment of Cushing's disease

The treatment of Cushing's disease is very complex and represents a challenge for clinicians. Transphenoidal surgical excision of adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma remains the treatment of choice but, unfortunately, the rate of cure at long-term follow-up is suboptimal and recurrences are high, even in the hands of skilled neurosurgeons. Other treatment options, such as bilateral adrenalectomy and pituitary radiotherapy, are currently in use but no treatment has proven fully satisfactory during the lengthy progress of this chronic and devastating disease. Nelson's syndrome and hypopituitarism are of particular concern as affected patients need lifelong hormone-replacement therapy and have notably increased mortality. Although medical treatment represents a second-line treatment option in patients with Cushing's disease, so far pharmacological therapy has been considered a transient and palliative treatment. Many drugs have been employed: they may act at the hypothalamic-pituitary level, decreasing ACTH secretion; at the adrenal level, inhibiting cortisol synthesis (steroidogenesis inhibitors); or at the peripheral level by competing with cortisol (glucocorticoid receptor antagonists). Recently, there has been renewed interest in the medical therapy of Cushing's disease and pituitary-directed drugs include old compounds commercially available for other diseases, such as cabergoline, and new promising compounds, such as pasireotide (SOM230) or retinoic acid. This review focuses on the tumor-directed pharmacological approaches for the management of Cushing's disease based on the recent identification of possibile targets at a pituitary level.

Pituitary-targeted medical therapy of Cushing's disease

BACKGROUND

The goals of ideal medical therapy for Cushing's disease should be to target the aetiology of the disorder, as is the case for surgery, which is the current 'gold standard' treatment. However, no effective drug that directly and reliably targets the adrenocorticotropin-secreting pituitary adenoma has yet been found.

OBJECTIVE

To summarise pituitary-targeted medical treatment of Cushing's disease.

METHODS

Compounds with neuromodulatory properties and ligands of different nuclear hormone receptors involved in hypothalamo-pituitary regulation have been investigated.

RESULTS

The somatostatin analogue pasireotide and the dopamine agonist cabergoline, as well as their combination, show some therapeutic promise in the medical therapy of Cushing's disease. Other treatments such as retinoic acid analogues look promising and may be a possible option for further investigation. No other medical therapies seem to be reliably effective currently.

CONCLUSION

Since a percentage of patients treated with surgery are not cured, or improve and subsequently relapse, there is an urgent need for effective medical therapies for this disorder. At present, only cabergoline and pasireotide are under active investigation.

Pharmacological management of Cushing's syndrome: an update

The treatment of choice for Cushing's syndrome remains surgical. The role for medical therapy is twofold. Firstly it is used to control hypercortisolaemia prior to surgery to optimize patient's preoperative state and secondly, it is used where surgery has failed and radiotherapy has not taken effect. The main drugs used inhibit steroidogenesis and include metyrapone, ketoconazole, and mitotane. Drugs targeting the hypothalamic-pituitary axis have been investigated but their roles in clinical practice remain limited although PPAR-gamma agonist and somatostatin analogue som-230 (pasireotide) need further investigation. The only drug acting at the periphery targeting the glucocorticoid receptor remains Mifepristone (RU486). The management of Cushing syndrome may well involve combination therapy acting at different pathways of hypercortisolaemia but monitoring of therapy will remain a challenge.

Advances in medical treatment of Cushing's disease

It is well known that transphenoidal surgery is the first line of treatment for Cushing's disease (CD). In case of recurrence, pituitary irradiation or adrenalectomy are usually performed; however, the morbidity due to these procedures is not negligible. For this reason, there is still a strong need for medical therapy, although there are only a few controlled data on this field. A variety of compounds are invaluable complementary tools in the management of this serious condition for which no treatment has yet been proven fully satisfactory. Pharmacological treatment could be employed by using neuromodulatory drugs (i.e., serotonin antagonists, dopamine, and GABA agonists) active only in a few cases of hypothalamic-pituitary-dependent CD. New approaches at the pituitary tumor level involve the potential use of other compounds (e.g., PPAR-γ agonists and retinoic acid). Exciting news in treating CD includes the recent availability of new multiligand somatostatin analogues. This review focuses on the new potential pharmacologic approaches for the management of CD based on the recent identification of possible targets and/or pathogenetic mechanisms.