Role of the addition of cabergoline to the management of acromegalic patients resistant to longterm treatment with octreotide LAR

Real-world value of cabergoline in the treatment of acromegaly

Cabergoline is an ergot derivative long-acting dopamine receptor 2 (DR2) selective agonist administered orally and widely used for the treatment of prolactin-secreting adenomas and Parkinson's disease. DR2 is expressed in most somatotroph adenomas. In acromegaly, cabergoline is used off-label and its role is limited by the relatively modest efficacy for achieving hormonal remission and thus, it is largely indicated in patients with mild elevation of GH/IGF-I postoperatively. It can be given as monotherapy, usually at a higher weekly dose than usually required to treat prolactinomas, but also as an add-on treatment in patients partially responding to the somatostatin receptor ligands octreotide or lanreotide. IGF-1 normalization with cabergoline can be achieved in about a third of the patients. Low baseline IGF-1 level (below 1.5 x ULN) before cabergoline initiation is a good predictor for remission. Combination treatment with the GH receptor antagonist pegvisomant can also be beneficial. The inexpensive, well-tolerated and convenient oral administration of cabergoline makes it an attractive medical therapy for active acromegaly.

Aggressive and Metastatic Pituitary Neuroendocrine Tumors: Therapeutic Management and Off-Label Drug Use

Pituitary neuroendocrine tumors (PitNETs) are the most common pituitary tumors and the second most common brain tumors. Although the vast majority (>90%) are benign, a small percentage (<2%) are aggressive. These aggressive PitNETs (AgPitNETs) are defined by the presence of radiological invasion, a high rate of cell proliferation, resistance to conventional treatments, and/or a high propensity for recurrence. Lastly, there are the rare pituitary carcinomas, also known as metastatic PitNETs (MetPitNETs), which account for only 0.2% of cases and are defined by the presence of craniospinal or distant metastases. At present, there are no definitive factors that allow us to predict with certainty the aggressive behavior of PitNETs, making the therapeutic management of AgPitNETs a real challenge. Surgery is considered the first-line treatment for AgPitNETs and MetPitNETs. Radiation therapy can be effective in controlling tumor growth and regulating hormone hypersecretion. Currently, there are no approved non-endocrine medical therapies for the management of AgPitNETs/MetPitNETs, mainly due to the lack of randomized controlled clinical trials. As a result, many of the medical therapies used are off-label drugs, and several are under investigation. Temozolomide (TMZ) is now recognized as the primary medical treatment following the failure of standard therapy (medical treatment, surgery, and radiotherapy) in AgPitNETs/MetPitNETs due to its ability to improve overall and progression-free survival rates in responding patients over 5 years. Other therapeutic options include pituitary-targeted therapies (dopamine agonists and somatostatin analogs), hormonal antisecretory drugs, non-hormonal targeted therapies, radionuclide treatments, and immunotherapy. However, the number of patients who have undergone these treatments is limited, and the results obtained to date have been inconsistent. As a result, it is imperative to expand the cohort of patients undergoing treatment to better determine the therapeutic efficacy and safety of these drugs for individuals with AgPitNETs/MetPitNETs.

Efficacy and Safety of Pegvisomant in the Treatment of Acromegaly

Pegvisomant, the first and currently only clinically available growth hormone receptor antagonist, is an effective therapeutic option for the medical treatment of acromegaly, a rare disorder characterized by excessive growth hormone secretion. With now over 20 years of real world experience, its safety and efficacy is well-established. However, several aspects of its clinical use are still controversially discussed. The high cost of pegvisomant has limited its use in several countries, and recent studies have reported a lower efficacy than the initial clinical trials. A reported increase in tumor volume under therapy varies between studies and has been attributed to either actual growth or re-expansion after cessation of somatostatin receptor ligand therapy. Furthermore, different combinations of pegvisomant and other therapeutic agents aiming at reduction of acromegaly disease activity have been proposed to increase or retain effectiveness while lowering side effects and cost. This review aims to assess current clinical data on the safety and efficacy of pegvisomant while also addressing controversies surrounding its use.

Effect of Cabergoline Treatment on Disease Control in Acromegaly Patients

The aim of this study was to evaluate the efficacy of cabergoline in normalizing plasma IGF-I levels in acromegaly patients with elevated IGF-I levels after surgery and/or SRL therapy. Acromegaly patients (n: 143) were evaluated retrospectively. Patients with elevated IGF-I levels after surgery and/or SRLs therapy and a fixed dose of SRLs treatment for the last six months with no history of radiotherapy in the last three years were included in the study (n: 12). Previous treatment regimens, baseline PRL and IGF-I levels (ULNR), sella MRI, and immunohistochemical findings were evaluated. Cabergoline was used as an add on (n: 11) or single medical treatment (n: 1). The median duration of treatment with SRL alone was 12 months (range 6-48 months). The mean IGF-I value before cabergoline therapy was 1.45±0.4 ULNR. The mean cabergoline dose and duration of treatment were 1.55±0.75 mg/week and 9±6.3 months, respectively. IGF-I normalization was only achieved in patients with serum IGF-I concentration<1.5×ULNR before the onset of cabergoline treatment (n: 9). In some of the patients with IGF-I normalization, baseline prolactin levels were normal (n: 3). Immunopositivity for prolactin in adenoma tissue was found in three patients with IGF-I normalization. Cabergoline therapy is effective in the normalization of IGF-I levels even in normoprolactinemic acromegaly patients when IGF-I levels are mildly or moderately elevated during SRL therapy.

Efficacy of cabergoline add-on therapy in patients with acromegaly resistance to somatostatin analogs treatment and the review of literature

Objective

It is reported that adding cabergoline to somatostatin analog (SSA) normalizes IGF-1 levels approximately in one-third of patients with acromegaly. We investigated the effect of combination therapy and potential predictors of response in patients with acromegaly who do not respond to SSA therapy alone.

Methods

Fifty acromegaly patients (M/F 23/27, mean age 50.88 ± 12.34 years) were divided into two groups as the active and control groups in this connection. Before and after treatment, we not only evaluated serum GH and IGF-1 levels and tumor size but also analyzed the factors relevant to the effect of the combined therapy.

Results

Adding cabergoline to SSA treatment led to IGF-1 normalization in 42% (21/50) of patients. Mean GH levels decreased from 2.64 ± 1.79 to 1.34 ± 0.99 ng/mL (p < .0001) and IGF-1 levels decreased from 432.92 ± 155.61 to 292.52 ± 126.15 ng/mL (p < .0001). GH and IGF-1 reduction in percent (%) were significantly higher in the controlled group (63% to 40%, p = 0.023 and 45% to 19%, p = 0.0001). Moreover, tumor size decrease was significantly higher in controlled group (-3.6 cm to -1.66 cm, p = 0.005).

Conclusion

According to the results of our study, the addition of cabergoline to SSA normalized IGF-1 levels in a considerable amount of acromegaly patients with a moderately elevated IGF-1 level, regardless of serum PRL levels. Besides, cabergoline treatment was also influential in patients with higher IGF-1 levels despite a lower remission rate.

Personalized Medical Treatment in Patients with Acromegaly: A Review

Acromegaly is associated with significant morbidity and mortality if not appropriately treated. In addition to insulin-like growth factor 1 (IGF-1) and growth hormone (GH) normalization, and tumor shrinkage, treatment goals include symptom relief, managing complications and improving quality of life. Surgical resection is a first-line treatment in most patients, with few being pretreated pre-operatively with medications. Somatostatin receptor ligands (SRLs), injectable and more recently oral capsules, have been the cornerstone of first-line medical therapy for persistent disease. However, several factors, including sparsely granulated adenomas, absent/low somatostatin receptor (SSTR2) status, imaging T2-hyperintensity, young age and aryl hydrocarbon receptor interacting protein mutations could predict first-generation SRL resistance. Patients with these characteristics may be better candidates for the GH receptor antagonist, pegvisomant, or in cases of large tumors the second-generation SRL, pasireotide. Combination therapy should be further pursued in patients who remain biochemically uncontrolled or have high remnant tumor after monotherapy. An efficacious and cost-effective pegvisomant dose-sparing effect of SRLs when used in combination has been demonstrated. With such a wide array of medical treatment options, it is increasingly important to tailor treatment to patients' unique characteristics as well as preferences, with a goal of personalizing management to achieve high quality outcomes.

Multimodal Non-Surgical Treatments of Aggressive Pituitary Tumors

Up to 35% of aggressive pituitary tumors recur and significantly affect mortality and quality of life. Management can be challenging and often requires multimodal treatment. Current treatment options, including surgery, conventional medical therapies such as dopamine agonists, somatostatin receptor agonists and radiotherapy, often fail to inhibit pituitary tumor growth. Recently, anti-tumor effects of chemotherapeutic drugs such as Temozolomide, Capecitabine, and Everolimus, as well as peptide receptor radionuclide therapy on aggressive pituitary tumors have been increasingly investigated and yield mixed, although sometimes promising, outcomes. The purpose of this review is to provide thorough information on non-surgical medical therapies and their efficacies and used protocols for aggressive pituitary adenomas from pre-clinical level to clinical use.

Effectiveness of Cabergoline Treatment in Patients with Acromegaly Uncontrolled with SSAs: Experience of a Single Tertiary Center

PURPOSE

To evaluate the effectiveness of cabergoline and the parameters affecting cabergoline response as add-on treatment to somatostatin analaogues (SSA) in patients with acromegaly uncontrolled with SSAs.

MATERIAL AND METHOD

One hundred and twenty-nine acromegalic patients uncontrolled with SSA who had cabergoline added to their treatment were included in this retrospective study. Patients were divided into the SSAs + cabergoline-responsive (group 1) and non-responsive groups (group 2), and biochemical, pathologic, and radiologic parameters were assessed.

RESULTS

IGF-1 normalization was achieved in 75 of 129 patients (58%) when cabergoline was added to the SSA treatment. Female patients were significantly higher in group 1 compared to group 2 (p=0.006). Group 1 had significantly smaller pre- and post-cabergoline tumor size (p=0.011, p=0.007 respectively), lower levels of IGF-1 in pre-and post-operative period (p=0.040, p=0.001), and lower levels of IGF-1 in pre- and post-cabergoline treatment (p<0.001). Cavernous invasion on sellar magnetic resonance imaging, dural invasion in pathologic examination were not significantly different between the groups. Sellar invasion in pathologic examination was significantly higher in group 1 (p=0.011). No significant difference was found in proliferation indices between two groups. The presence of fibrous bodies was significantly lower in group 1 (p=0.010).

CONCLUSION

Cabergoline can be added to the treatment of acromegalic patients uncontrolled with SSAs due to its ease of use and low economic cost, especially in patients with acromegaly who have small adenomas and no fibrous bodies.

Acromegaly: Update on Management and Long-Term Morbidities

Acromegaly is a systemic disease associated with great morbidity and increased mortality if not adequately treated. In the past decades much improvement has been achieved in its treatment and in the knowledge of its comorbidities. We provide an update of acromegaly management with current recommendations. We also address long-term comorbidities emphasizing the changing face of the disease in more recent series, with a decrease of cardiovascular disease severity and an increased awareness of comorbidities like bone disease, manifested mainly as vertebral fractures and the change in the main cause of death (from cardiovascular disease to cancer in more recent series).

The Role of Dopamine Agonists in Pituitary Adenomas

Dopamine agonist therapy is the primary therapy for prolactin-secreting adenomas and usually results in normoprolactinemia, eugonadism, and tumor reduction. Cabergoline is superior to bromocriptine with regard to efficacy and tolerance. Withdrawal of cabergoline can be attempted in patients with normal prolactin levels on low doses of medication and evidence of radiographic tumor involution. Dopamine agonists have been used off label in patients with acromegaly, Cushing disease, and nonfunctioning adenomas. A trial of cabergoline monotherapy can be effective in patients with biochemically mild acromegaly. Cabergoline combination with somatostatin receptor ligands or pegvisomant improves insulin-like growth factor level 1 in majority of patients.

Management of persistent acromegaly following primary therapy: The current landscape in the UK

Acromegaly is the clinical consequence of chronic exposure of the tissues to excess GH and IGF-I. It is almost exclusively the result of a GH-secreting pituitary adenoma. In addition to the somatic features, uncontrolled acromegaly is associated with a number of complications and excess mortality. Management is aimed at control of the tumour; normalization of GH and IGF-I secretion and relief of symptoms. Initial management of GH-secreting pituitary adenoma is widely accepted as endonasal trans-sphenoidal surgery, with second-line therapy where disease is uncontrolled in most cases being somatostatin analogue therapy. With the combination of surgery and somatostatin analogue therapy, control is achieved in around 75% of patients; however, this leaves a significant proportion of patients requiring multimodality therapy to achieve remission. Within the UK, the health system has finite resources, and decisions for management require consideration of efficacy and cost-effectiveness. To add to the complexity, subtle differences exist in availability of high-cost medications used in the treatment of patients with acromegaly across the devolved nations of the UK. In this article, we discuss options for the management of persistent acromegaly following initial surgery and somatostatin analogue therapy, and explore earlier use of dopaminergics and conservative management.

Italian Association of Clinical Endocrinologists (AME) and Italian AACE Chapter Position Statement for Clinical Practice: Acromegaly - Part 2: Therapeutic Issues

Any newly diagnosed patient should be referred to a multidisciplinary team experienced in the treatment of pituitary adenomas. The therapeutic management of acromegaly always requires a personalized strategy. Normal age-matched IGF-I values are the treatment goal. Transsphenoidal surgery by an expert neurosurgeon is the primary treatment modality for most patients, especially if there are neurological complications. In patients with poor clinical conditions or who refuse surgery, primary medical treatment should be offered, firstly with somatostatin analogs (SSAs). In patients who do not reach hormonal targets with first-generation depot SSAs, a second pharmacological option with pasireotide LAR or pegvisomant (alone or combined with SSA) should be offered. Irradiation could be proposed to patients with surgical remnants who would like to be free from long-term medical therapies or those with persistent disease activity or tumor growth despite surgery or medical therapy. Since the therapeutic tools available enable therapeutic targets to be achieved in most cases, the challenge is to focus more on the quality of life.

Multimodal therapy in aggressive pituitary tumors

The concept of aggressive pituitary tumor (APT) has been precisely defined in recent years. These tumors are characterized by morphological (radiological or histopathological) data of invasion, proliferative activity superior to that of typical adenomas and a clinical behavior characterized by resistance to standard therapies and frequent recurrences. The absence of cerebrospinal or distant metastases differentiates them from the pituitary carcinoma. APTs account for about 10% of all pituitary neoplasm. Proper diagnostic implies participation not only of radiological and hormonal investigation but also a thorough pathological assessment including proliferation markers and immunohistochemistry for hormones and transcription factors. Surgical resection, aiming gross total resection or tumor debulking, is the mainstay initial therapy in most patients. Most patients with APTs need more than one surgical intervention, pituitary radiation, sometimes on more than one occasion, and multiple sequential or combined medical treatments, to finally be doomed to unusual treatments, such as alkylating agents (temozolomide alone or in combination), molecular targeted therapies, or peptide receptor radionuclide therapy. Multimodal therapy, implemented by experts, preferably in specialized centers with high volume caseload, is the only way to improve the prognosis of patients with these uncommon tumors. The research needs in this area are multiple and include a greater knowledge of the molecular biology of these tumors, establishment of protocols for monitoring and sequencing of treatments, development of multicenter studies and international registries.

The position of combined medical treatment in acromegaly

Advances in combination medical treatment have offer new perspectives for acromegaly patients with persistent disease activity despite receiving the available medical monotherapies. The outcomes of combination medical treatment may reflect both additive and synergistic effects. This review focuses on combination medical treatment and its current position in acromegaly, based on clinical studies evaluating the efficacy and safety of combined medical treatment(s) and our own experiences with combination therapy. Arch Endocrinol Metab. 2019;63(6):646-52.

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.

Treatment escape reduces the effectiveness of cabergoline during long-term treatment of acromegaly in monotherapy or in association with first-generation somatostatin receptor ligands

BACKGROUND

Few studies evaluated the use of cabergoline (CAB) for acromegaly treatment in monotherapy or in combination with first-generation somatostatin receptor ligands (SRLs).

AIM

To evaluate the efficacy, predictors of response and safety of CAB treatment in acromegaly both in monotherapy and in combination with SRLs.

METHODS

We retrospectively collected demographic, biochemical, tumour and treatment data. Short-term disease control was defined as random GH level < 1.0 μg/L and normal age-matched IGF-I level after 3-6 months of treatment with the higher dose used. Long-term disease control was defined as maintenance of normal GH and IGF-I levels at the last visit (at least 9 months of treatment).

RESULTS

Eighty-two patients were studied. The median total time of treatment in monotherapy or in combination with SRLs was 14 months (3-124) and 34 months (3-88), respectively. Short-term disease control was observed in 6 (21%) patients in the monotherapy group and in 20 (32%) in the combination group. Treatment escape was observed in 1 patient after 16 months of CAB monotherapy and in 6 (30%) patients with combination therapy (after a median of 38 months), resulting in long-term disease control of 18% and 23%, respectively. Hyperprolactinemia was a predictor of response to monotherapy and pretreatment GH level to combination treatment.

CONCLUSION

We presented the results of the largest single-centre study with CAB in monotherapy and in combination with SRL. The efficacy of CAB in acromegaly seems to be lower than that of other drugs, and treatment escape may occur after a long-term follow-up.

Increasing frequency of combination medical therapy in the treatment of acromegaly with the GH receptor antagonist pegvisomant

Pegvisomant monotherapy is effective and safe in treatment of acromegaly. However, some clinicians combine pegvisomant with somatostatin analogues (SSA) or dopamine agonist (DA). In this analysis of ACROSTUDY, a long-term non-interventional study, the use of combination regimens was evaluated. Based on their baseline treatment, 2043 patients were retrospectively categorized as: long-acting SSA combined with pegvisomant, 'Combo SSA' 768 patients (38%); DA combined with pegvisomant, 'Combo DA' 123 (6%); pegvisomant monotherapy, 'Peg mono' 1128 (55%). Treatment patterns changed over the 10-year period, with recent patients more likely to receive any combination (20% in 2003 vs 54% in 2012). Combo SSA use varied widely among countries from 22% to 78%. Exposure periods of the three treatment modalities were defined from pegvisomant start until the last visit in ACROSTUDY; patients could switch treatment categories. At year 4, IGF-I was normal in 62% of Combo SSA, 63% of Combo DA and 65% of Peg mono groups. Pegvisomant was initiated as daily injections in 94% of patients in the Peg mono group, 66% of Combo SSA and 91% of Combo DA patients. During 6169 years of treatment exposure, 3424 adverse events (AEs) were reported in 946 (51%) patients, of which 617 (18%) were serious and 401 (12%) were considered treatment related. The reported incidence of serious AEs and treatment-related non-serious AEs were similar among the three treatment modalities. This analysis describes real-world clinical care and shows favorable efficacy and safety for Peg mono and combinations. Novel findings include an increased use of combination therapy over time and variability in treatment modalities between countries.

MANAGEMENT OF ENDOCRINE DISEASE: Personalized medicine in the treatment of acromegaly

Acromegaly is associated with high morbidity and elevated mortality when not adequately treated. Surgery is the first-line treatment for most patients as it is the only one that can lead to immediate cure. In patients who are not cured by surgery, treatment is currently based on a trial-and-error approach. First-generation somatostatin receptor ligands (fg-SRL) are initiated for most patients, although approximately 25% of patients present resistance to this drug class. Some biomarkers of treatment outcome are described in the literature, with the aim of categorizing patients into different groups to individualize their treatments using a personalized approach. In this review, we will discuss the current status of precision medicine for the treatment of acromegaly and future perspectives on the use of personalized medicine for this purpose.

Management of aggressive growth hormone secreting pituitary adenomas

Aggressive GH-secreting pituitary adenomas (GHPAs) represent an important clinical problem in patients with acromegaly. Surgical therapy, although often the mainstay of treatment for GHPAs, is less effective in aggressive GHPAs due to their invasive and destructive growth patterns, and their proclivity for infrasellar invasion. Medical therapies for GHPAs, including somatostatin analogues and GH receptor antagonists, are becoming increasingly important adjuncts to surgical intervention. Stereotactic radiosurgery serves as an important fallback therapy for tumors that cannot be cured with surgery and medications. Data suggests that patients with aggressive and refractory GHPAs are best treated at dedicated tertiary pituitary centers with multidisciplinary teams of neuroendocrinologists, neurosurgeons, radiation oncologists and other specialists who routinely provide advanced care to GHPA patients. Future research will help clarify the defining features of "aggressive" and "atypical" PAs, likely based on tumor behavior, preoperative imaging characteristics, histopathological characteristics, and molecular markers.

Cabergoline in acromegaly

Acromegaly, a rare disease due to growth hormone (GH) hypersecretion by a pituitary adenoma, is associated with severe comorbidity and premature death if not adequately treated. The usual first-line treatment is surgery. Various drugs, including somatostatin receptor ligands, dopamine agonists and GH receptor antagonists, are now available for use if surgery fails to suppress GH/IGF-I hypersecretion. Cabergoline, now the preferred dopamine agonist for treating hyperprolactinemia, is also used off-label for treating acromegaly. Cabergoline monotherapy is reported to normalize IGF-I levels in more than one-third of patients with acromegaly. When a somatostatin receptor ligand proves ineffective, cabergoline add-on therapy normalizes the IGF-I level in 40-50% of patients. Finally, when combined with the GH receptor antagonist pegvisomant in patients with mild uncontrolled disease, cabergoline helps to achieve normal IGF-I levels while avoiding the need for high-dose pegvisomant. Cabergoline is also inexpensive and well tolerated; in particular, it does not appear to promote heart valve disease.

The role of combination medical therapy in the treatment of acromegaly

PURPOSE

Uncontrolled acromegaly results in approximately 2-fold excess mortality. Pituitary surgery is first-line therapy, and medical treatment is indicated for persistent disease. While cabergoline and pegvisomant are used in select patients, somatostatin receptor ligands (SRLs) remain the cornerstone of medical treatment. Management of patients poorly responsive to SRLs is therefore, challenging. The purpose of this review is to highlight the options for combination medical therapy in the treatment of acromegaly, with an emphasis on efficacy and safety.

METHODS

All original articles/abstracts detailing combination medical therapy in acromegaly were identified from a PubMed search.

RESULTS

Studies reviewed included retrospective and open-label prospective studies. While the combination of SRL and cabergoline was generally well tolerated, a lower baseline insulin-like growth factor-1 (IGF-1) level was the best predictor of efficacy; this combination may be most effective in patients with mildly elevated IGF-1. SRL-pegvisomant combination normalized IGF-1 in the majority of patients; continued efficacy despite individual drug dosing reduction was also reported. The risk of significant liver enzyme elevation was, however, higher than that reported with SRL monotherapy; close monitoring is recommended. Data on pegvisomant-cabergoline combination is limited, but this may be an option in the setting of SRL intolerance. Reports on temozolomide used in combination with other medical therapies in patients with aggressive GH-secreting tumors are also summarized.

CONCLUSION

While more prospective, randomized controlled trials on long-term efficacy and safety are needed, combination medical therapy remains a treatment strategy that should be considered for acromegaly patients poorly responsive to SRLs.

Somatostatin analogs, cabergoline and pegvisomant: comparing the efficacy of medical treatment for acromegaly

Therapies for acromegaly aim at normalizing hormonal excess and controlling tumor growth . Therapeutic approaches are surgery, pharmacotherapy and radiotherapy. Area covered: This review focuses on the role of medical therapy of acromegaly, comparing the efficacy of somatostatin analogues (SSA), dopamine-agonists (DA) and pegvisomant (PEG), the three available drug classes for treating acromegaly. To clarify the difference in response rates reported in the literature for these therapies, we performed a search for original articles published in PubMed. SSA represent the first-line approach to medical treatment. This therapy is effective in controlling acromegaly in about 40% of patients, however there are great differences in the reported hormonal efficacy of SSA in the different series. In patients partially resistant to SSA, cabergoline can be added when hormonal levels are close to normalization, resulting effective in control IGF-I levels in 43% of patients. In patients with higher hormonal levels PEG is indicated, normalizing IGF-I levels in 79.8% and 80.6% of cases when used in monotherapy or in combination with SSA. Pasireotide, the newly developed SSA multi-ligand receptor, represents a new option in SSA resistant patients. Expert commentary: Medical therapy represents an important therapeutic option resulting safe and effective in controlling acromegaly in a high percentage of patients. The best treatment should be individually tailored for each patient, taking into account sex, age, comorbidities, tumor characteristics and hormonal levels.

Medical combination therapies in Cushing's disease

INTRODUCTION

There has been growing interest on medical therapy for the management of Cushing's disease (CD), particularly in cases of persistent or recurrent hypercortisolism. Ketoconazole, an inhibitor of adrenal steroidogenesis, is the most widely used drug, whereas cabergoline and pasireotide are the most promising centrally acting agents. The main purpose of this review article is to highlight the options of medical treatment for CD, with a special emphasis on combination therapies, a topic that has only been addressed by a limited number of studies.

CONCLUSIONS

According to the results of these studies, combination therapies involving medications with additive or synergistic effects on ACTH and cortisol secretion seem quite attractive as they yield higher probability of longterm control of the hypercortisolism at lower doses, a lower incidence of side-effects, and possibly a lower rate of treatment escapes. Currently, ketoconazole, cabergoline, and pasireotide are the best drugs to be prescribed in combination.

Cabergoline use for pituitary tumors and valvular disorders

Cabergoline (CAB) is widely used for the medical treatment of pituitary tumors, particularly those associated with hormone hypersecretion. Whether treatment with CAB is associated with an increased risk of clinically relevant cardiac valve disease in patients with pituitary tumors is still debated. In most studies, CAB has been found not associated with an increased risk of significant valvulopathy, and no correlation has been shown between valvular abnormalities and CAB duration or cumulative dose. This review provides an overview of the studies reporting on the outcome of CAB in terms of cardiac valve disease in patients with pituitary tumors.

Cabergoline treatment in acromegaly: cons

Many options are available for the treatment of acromegaly, including surgery, radiotherapy, and medical treatment. Cabergoline (CAB), a dopamine agonist with high affinity for dopamine receptor type 2, has been used both in monotherapy and in conjunction with somatostatin analogs (SSAs). Although it is administered orally and has a relatively lower-cost in comparison with SSAs, few studies have demonstrated its usefulness, there is a lack of randomized-controlled trials and other drugs (SSAs and pegvisomant) with more data in the literature are available; these issues are the main drawbacks of adopting CAB for the treatment of acromegaly.

Multiple facets in the control of acromegaly

AIMS

The current article provides a brief overview of the criteria for defining disease control in acromegaly.

METHODS

This was a retrospective, narrative review of previously published evidence chosen at the author's discretion along with an illustrative case study from Latin America.

FINDINGS AND CONCLUSIONS

In the strictest sense, "cure" in acromegaly is defined as complete restoration of normal pulsatile growth hormone secretion, although this is rarely achieved. Rather than "cure", as such, it is more appropriate to refer to disease control and remission, which is defined mainly in terms of specific biochemical targets (for growth hormone and insulin-like growth factor-1) that predict or correlate with symptoms, comorbidities and mortality. However, optimal management of acromegaly goes beyond biochemical control to include control of tumour growth (which may be independent of biochemical control) and comprehensive management of the symptoms and comorbidities typically associated with the disease, as these may not be adequately managed with acromegaly-specific therapy alone.

A practical approach to acromegaly management in Latin America

INTRODUCTION

Evidence-based treatment guidelines have undoubtedly advanced medical practice and supported optimal management of acromegaly, but their application may be hampered by limited access to the latest treatment options.

METHODS

In this retrospective, narrative review, the authors revisited existing treatment guidelines for acromegaly in Latin America. These were considered in conjunction with published evidence chosen at the authors' discretion.

FINDINGS

In a socially and economically diverse region, such as Latin America, any regional practice guidelines need to appreciate that recommended treatment options, such as surgery by expert pituitary surgical teams and drug therapies, especially somatostatin analogs, are often not available due to limited resources. In these instances, physicians may be obliged to apply less effective therapeutic options.

CONCLUSIONS

The current article looks at the practical aspects of acromegaly management in Latin America and discusses this in the context of existing guidelines. Furthermore, we consider potential strategies to make better use of resources through combination and multimodal approaches to treatment.

The role of combination medical therapy in acromegaly: hope for the nonresponsive patient

PURPOSE OF REVIEW

This review focuses on combination drug treatment for acromegaly patients, including novel concepts and experimental therapies, with an emphasis on the author's personal experience.

RECENT FINDINGS

A review of published clinical studies demonstrates that combination therapy; somatostatin receptor ligands and dopamine agonists, somatostatin receptor ligands and pegvisomant, or cabergoline and pegvisomant could provide significant additive biochemical control of acromegaly in patients inadequately controlled with conventional somatostatin receptor ligand therapy.

SUMMARY

Advances in combination medical therapy have opened up new perspectives for acromegaly patients who are poorly, or nonresponsive to, presently available single drug therapies.

Acromegalic patients lost to follow-up: a pilot study

Approximately 50 % of all acromegalic patients will require lifelong medical treatment to normalize mortality rates and reduce morbidity. Thus, adherence to therapy is essential to achieve treatment goals. To date, no study has evaluated the frequency and reasons for loss to follow-up in the acromegalic population. The current study aimed at evaluating the frequency of acromegalic patient loss to follow-up in three reference centers and the reasons responsible for their low compliance with treatment. All of the files for the acromegalic patients in the three centers were reviewed. Those patients, who had not followed up with the hospital for more than a year, were contacted via phone and/or mail and invited to participate. Patients who agreed to participate were interviewed, and blood samples were collected. A total of 239 files were reviewed; from these 42 patients (17.6 %) were identified who were lost to follow-up. It was possible to contact 27 of these patients, 10 of whom did not attend the appointments for more than one time and 17 of whom agreed to participate in the study. Fifteen of these 17 patients had active disease (88.2 %), and all of the patients restarted treatment in the original centers. The main reason for loss to follow-up was an absence of symptoms. High-quality follow-up is important in acromegaly to successfully achieve the aims of the treatment. An active search for patients may allow the resumption of treatment in a significant proportion of these cases, contributing to reduced morbidity and mortality in this patient population.

The place of medical treatment of acromegaly: current status and perspectives

INTRODUCTION

Acromegaly is characterized by elevated growth hormone (GH) and insulin-like growth factor-I (IGF-I) levels and by progressive somatic disfigurement and systemic manifestations, which lead to a mortality rate higher than the general population. Therefore, diagnosis and properly treatment should be performed as soon as possible.

AREAS COVERED

This article focuses on the state of the art of acromegaly medical treatment. Somatostatin analogs, dopamine agonists and GH receptor antagonist were reviewed. Somatostatin analogs, the first-choice pharmacotherapy, can be used as primary or pre-operative treatment or as secondary therapy after failed surgery. Dopamine agonists have been used in patients with slightly elevated hormone levels and/or mixed GH/prolactin adenomas. Pegvisomant is indicated for resistant to somatostatin analogs/dopamine agonists. Combined treatment is also an option for resistant cases. Other non-conventional therapies and perspectives of treatment were also been discussed.

EXPERT OPINION

The control of disease activity in acromegaly is of paramount importance. Medical treatment is an important option for cases in which surgery was unsuccessful or not indicated. Despite the achievements in medical treatment, somatotropic tumor aggressiveness and/or resistance to the drugs currently available remain a concern. Therefore, novel therapy targets based on molecular pathogenesis of GH-secreting tumors are currently in development, aiming at fulfilling this important gap.

Resistance to octreotide LAR in acromegalic patients with high SSTR2 expression: analysis of AIP expression

We present here the clinical and molecular data of two patients with acromegaly treated with octreotide LAR after non-curative surgery, and who presented different responses to therapy. Somatostatin receptor type 2 and 5 (SSTR2 and SSTR5), and aryl hydrocarbon receptor-interacting protein (AIP) expression levels were analyzed by qPCR. In both cases, high SSTR2 and low SSTR5 expression levels were detected; however, only one of the patients achieved disease control after octreotide LAR therapy. When we analyzed AIP expression levels of both cases, the patient whose disease was controlled after therapy exhibited AIP expression levels that were two times higher than the patient whose disease was still active. These two cases illustrate that, although the currently available somatostatin analogs bind preferentially to SSTR2, some patients are not responsive to therapy despite high expression of this receptor. This difference could be explained by differences in post-receptor signaling pathways, including the recently described involvement of AIP. Arq Bras Endocrinol Metab. 2012;56(8):501-6