Hypothesis: Extra-hepatic acromegaly: a new paradigm?

Growth hormone receptor antagonist pegvisomant and its role in the medical therapy of growth hormone excess

Pegvisomant is a growth-hormone (GH) receptor antagonist that prevents the formation of the active heterotrimer of the dimerised GH receptor and the GH molecule necessary for downstream signal transduction. Over the past 20 years, it has become a key therapeutic option for physicians treating syndromes of GH/IGF-1 excess. Sufficient longitudinal follow-up data suggest that it can be deemed both safe and effective. It is the drug with the greatest potential for achieving an amelioration of the biochemical effects of GH excess with a corresponding normalisation of IGF-1 levels; however, insufficient dose titration has lessened real-world therapeutic outcomes. Theoretical concerns about stimulating tumour growth have been resolved as this has not been observed, while derangement of liver enzymes and local skin-related adverse reactions may occur in a minority of the patients. It may be a particularly impactful medication for the treatment of children, young people, and those with inherited disorders of GH excess, where other treatment modalities often fail. Combination therapy of pegvisomant with first- and second-generation somatostatin receptor ligands or with dopamine agonists remains an ongoing area of interest and research. High cost remains a barrier to the use of pegvisomant in many settings.

Age-Related Hormones Changes and Its Impact on Health Status and Lifespan

The increase in life expectancy is accompanied with an increased consultation of age-related pathologies including endocrine disorders. Two main areas are focusing the attention of medical and social research in older population: the diagnosis and care of this heterogeneous population, and the interventional measures potentially useful to mitigate age-related functional declines and to increase health and quality of lifespan. Thus, better understanding the physiopathology of aging and establishing accurate diagnostic and personalized approaches are a priority and currently an unmet need of the medical community. The endocrine system plays a major role in survival and lifespan through regulating vital processes such as energy consumption and optimizing the stress response among others. The aim of this paper is to review the physiological evolution of the main hormonal functions in aging and its clinical translation to improve our approach to the aging patient.

Ectopic lipid deposition and insulin resistance in patients with GH disorders before and after treatment

OBJECTIVES

Insulin resistance is associated with ectopic lipid deposition. Growth hormone (GH) status also modulates ectopic lipid accumulation, but how this associates with insulin resistance in patients with GH disorders is not well established.

DESIGN AND METHODS

Twenty-one patients diagnosed with acromegaly and 12 patients with adult GH deficiency (GHD) were studied at diagnosis and after treatment. A reference group of 12 subjects was included. Each study day comprised assessment of body composition with dual-energy X-ray absorptiometry, ectopic lipid deposition in the liver by MR spectroscopy, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Disease control of acromegaly decreased lean body mass (LBM) (P < .000) and increased the percentage of total body fat (TBF) (P < .000). GH replacement increased LBM in the GHD patients (P = .007) and decreased the percentage of TBF (P = .010). The intrahepatic lipid (IHL) content increased after disease control in acromegaly (P = .004), whereas IHL did not change significantly after GH replacement in GHD (P = .34). Insulin resistance (HOMA-IR) improved after disease control of acromegaly (P < .000) and remained unaltered after GH replacement in the GHD patients (P = .829).

CONCLUSIONS

GH status is a significant modulator of body composition and insulin sensitivity.GH excess reduces total fat mass and intrahepatic lipid content together with induction of insulin resistance.The data support the notion that GH-induced insulin resistance is unassociated with hepatic lipid accumulation.

Evaluating the Impact of Acromegaly on Quality of Life

Acromegaly has a substantial negative impact on quality of life (QoL). This review aims to discuss the impact of acromegaly on QoL from the clinical perspective as well as from the patient perspective. Furthermore, it aims to evaluate the use of patient-reported outcome measures (PROMs) in acromegaly and how PROMs aid decision-making. The recommendations presented in this review are based on recent clinical evidence on the impact of acromegaly on QoL combined with the authors' own clinical experience treating patients with acromegaly. We recommend that a patient-centered approach should be considered in treatment decisions, integrating conventional biochemical outcomes, tumor control, comorbidities, treatment complications, and PROMs, including QoL measures. This more integrated approach seems effective in treating comorbidities and improving patient-reported outcomes and is critical, as many patients do not achieve biochemical or tumor control and comorbidities, impairment in QoL may not remit even when full biochemical control is achieved.

Dissecting the in vitro efficacy of octreotide and cabergoline in GH- and GH/PRL-secreting pituitary tumors

CONTEXT

Cabergoline (CAB) is an off-label medical therapy for acromegaly, overshadowed by first-generation somatostatin receptor ligands, e.g. octreotide (OCT).

OBJECTIVE

Head-to-head comparison between OCT and CAB in inhibiting growth hormone (GH) secretion in primary cultures of GH- and GH/PRL-secreting tumors. To investigate the role of somatostatin (SST) and dopamine type 2 (D2R) receptor expression.

DESIGN

To evaluate the antisecretory effect of OCT and CAB, together with receptor mRNA expression, in 23 tumor cultures.

SETTING AND PATIENTS

Acromegaly patients referred to the Erasmus Medical Center (Rotterdam, The Netherlands).

INTERVENTIONS

72-hour OCT and CAB treatment (10 nM).

MAIN OUTCOME MEASURES

GH concentrations in cell culture media.

RESULTS

OCT showed a slightly higher efficacy compared with CAB (GH decrease -39.5% vs. -32.5%, p = 0.079). The effect of the two drugs was superimposable in GH/PRL co-secreting tumors (-42.1% vs. -44.8%), where SST1 and D2R had a higher expression compared to the pure GH-secreting ones (p = 0.020 and p = 0.026). OCT was more effective than CAB in 8/23 cultures, while CAB was more effective than OCT in 3/23 (CAB + group). In CAB + tumors, SST1 expression was higher compared to the other groups (p = 0.034). At ROC curve analysis, SST1 and D2R discriminated between GH and GH/PRL co-secretion (AUC 0.856, p = 0.013; AUC 0.822, p = 0.024). SST1 was the best predictor of CAB response (≥50% GH reduction, AUC 0.913, p = 0.006; 80% sensitivity, 94% specificity).

CONCLUSIONS

OCT is 5-10% more effective than CAB in vitro. SST1 mRNA expression can represent a reliable marker of GH/PRL co-secreting tumors showing a preferential response to CAB treatment.

Mean GH profile is more accurate than single fasting GH in the evaluation of acromegaly disease control during somatostatin receptor ligands therapy

PURPOSE

This study aims to compare the accuracy of mean GH profile (GHP) < 2.5 ng/ml and single fasting GH (SGH) < 1 ng/ml in the evaluation of disease control in acromegaly patients during somatostatin receptor ligands (SRLs) therapy.

METHODS

We retrospectively enrolled 100 acromegaly patients, 68 responder, and 32 partial responder to SRLs. Controlled disease has been defined as IGF-I levels within age-related normal limits, while partial response as pathological IGF-I values despite a reduction ≥ 50%. In all patients, GHP, SGH, IGF-I, and IGFBP-3 were evaluated.

RESULTS

Median GHP levels (1.2 ng/ml, IQR 0.5-2.3 ng/ml) were lower (p = 0.001) than SGH (1.9 ng/ml, IQR 1.0-3.6 ng/ml). Accuracy of GHP was 81%, whereas that of SGH was 55%, with a Kappa index of 0.520 and 0.237, respectively. In multivariable analysis GHP (p = 0.002) and IGFBP-3 (p = 0.004), but not SGH, were independently associated with normal IGF-I levels. At receiver-operator characteristic curve (ROC) analysis GHP cut-off sensitivity and specificity were 94.1% and 50.0%, respectively, while SGH sensitivity and specificity were 35.3% and 93.7%, respectively. Finally, in obese patients the GH cut-off level (both as SGH and GHP) associated to good disease control was significantly different with respect to not obese ones.

CONCLUSIONS

GHP associates with IGF-I (and therefore with appropriate control of disease) with higher accuracy than SGH. When GH evaluation is needed, the measurement of mean GHP should be preferred and use of BMI-related cut-offs is suggested.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

Nonalcoholic Fatty Liver Disease and Endocrine Axes—A Scoping Review

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease. NAFLD often occurs associated with endocrinopathies. Evidence suggests that endocrine dysfunction may play an important role in NAFLD development, progression, and severity. Our work aimed to explore and summarize the crosstalk between the liver and different endocrine organs, their hormones, and dysfunctions. For instance, our results show that hyperprolactinemia, hypercortisolemia, and polycystic ovary syndrome seem to worsen NAFLD’s pathway. Hypothyroidism and low growth hormone levels also may contribute to NAFLD’s progression, and a bidirectional association between hypercortisolism and hypogonadism and the NAFLD pathway looks likely, given the current evidence. Therefore, we concluded that it appears likely that there is a link between several endocrine disorders and NAFLD other than the typically known type 2 diabetes mellitus and metabolic syndrome (MS). Nevertheless, there is controversial and insufficient evidence in this area of knowledge.

Towards an Earlier Diagnosis of Acromegaly and Gigantism

Acromegaly is a rare disease and the clinical features of acromegaly develop insidiously; its diagnosis is often significantly delayed. Therefore, earlier diagnosis will improve the quality of life of the patient and reduce the need for other therapies to control the initial and ongoing damage that acromegaly presents. In this chapter, we describe the view of the patient and the clinician on the importance of earlier diagnosis, as well as on what can be done to speed up this process. Earlier diagnosis will not only improve quality of life and the burden of disease in acromegaly patients, but it will also have a positive impact in the economic burden of this rare disease.

Discordant GH and IGF-1 Results in Treated Acromegaly: Impact of GH Cutoffs and Mean Values Assessment

CONTEXT

Discordant growth hormone (GH) and insulin-like growth factor-1 (IGF-1) values are frequent in acromegaly.

OBJECTIVE

To evaluate the impact of different GH cutoffs on discordance rate. To investigate whether the mean of consecutive GH measurements impacts discordance rate when matched to the last available IGF-1 value.

DESIGN

Retrospective study.

SETTING

Referral center for pituitary diseases.

PATIENTS

Ninety acromegaly patients with at least 3 consecutive evaluations for GH and IGF-1 using the same assay in the same laboratory (median follow-up 13 years).

INTERVENTIONS

Multimodal treatment of acromegaly.

MAIN OUTCOME MEASURES

Single fasting GH (GHf) and IGF-1 (IGF-1f). Mean of 3 GH measurements (GHm), collected during consecutive routine patients' evaluations.

RESULTS

At last evaluation GHf values were 1.99 ± 2.79 µg/L and age-adjusted IGF-1f was 0.86 ± 0.44 × upper limit of normality (mean ± SD). The discordance rate using GHf was 52.2% (cutoff 1 µg/L) and 35.6% (cutoff 2.5 µg/L) (P = 0.025). "High GH" discordance was more common for GHf <1.0 µg/L, while "high IGF-1" was predominant for GHf <2.5 µg/L (P < 0.0001). Using GHm mitigated the impact of GH cutoffs on discordance (GHm <1.0 µg/L: 43.3%; GHm <2.5 µg/L: 38.9%; P = 0.265). At receiver-operator characteristic curve (ROC) analysis, both GHf and GHm were poor predictors of IGF-1f normalization (area under the curve [AUC] = 0.611 and AUC = 0.645, respectively). The prevalence of disease-related comorbidities did not significantly differ between controlled, discordant, and active disease patients.

DISCUSSION

GH/IGF-1 discordance strongly depends on GH cutoffs. The use of GHm lessen the impact of GH cutoffs. Measurement of fasting GH levels (both GHf and GHm) is a poor predictor of IGF-1f normalization in our cohort.

Effects of tissue-specific GH receptor knockouts in mice

Growth hormone (GH) is pituitary derived hormone which acts on most tissues of the body either directly or indirectly and affects many metabolic processes throughout life. Genetically engineered mouse lines have become vital tools for uncovering the various in vivo activities of a GH. A particularly useful mouse line has been the GH receptor (GHR) gene disrupted or knockout (KO) mouse which has been used world-wide in many studies. Recent advances in biotechnology have allowed the development of tissue-specific knockout mouse lines which allows for more direct enquiries on the activities of a given protein in specific tissues or cell types. Accordingly, twenty-two novel tissue-specific GHRKO mouse lines have been developed in the last eleven years. In this paper we provide a detailed list and review the phenotypic changes that occur in each of these tissue-specific GHRKO mouse lines.

Soluble Klotho: a possible predictor of quality of life in acromegaly patients

PURPOSE

Although quality of life (QoL) is improved in patients with acromegaly after disease control, QoL correlates only weakly with traditional biomarkers. Our objective is to investigate a potential relation between the new serum biomarker soluble Klotho (sKlotho), GH and insulin-like growth factor 1 (IGF-1) levels, and QoL.

METHODS

In this prospective cohort study, we investigated 54 acromegaly patients biochemically well-controlled on combination treatment with first-generation somatostatin receptor ligands (SRLs) and pegvisomant (PEGV) at baseline and 9 months after switching to pasireotide LAR (PAS-LAR; either as monotherapy, n = 28; or in combination with PEGV, n = 26). QoL was measured by the Patient-Assessed Acromegaly Symptom Questionnaire (PASQ) and Acromegaly Quality of Life (AcroQoL) questionnaire.

RESULTS

Switching to PAS-LAR treatment significantly improved QoL without altering IGF-1 levels. QoL did not correlate with GH or IGF-1 levels, but sKlotho correlated with the observed improvements in QoL by the AcroQoL global (r = -0.35, p = 0.012) and physical subdimension (r = -0.34, p = 0.017), and with PASQ headache (r = 0.28, p = 0.048), osteoarthralgia (r = 0.46, p = 0.00080) and soft tissue swelling score (r = 0.29, p = 0.041). Parallel changes in serum sKlotho and IGF-1 (r = 0.31, p = 0.023) suggest sKlotho and IGF-1 to be similarly dependent on GH. Comparing the PAS-LAR combination therapy and the monotherapy group we did not observe a significant difference in improvement of QoL.

CONCLUSIONS

Patients experienced improved QoL during PAS-LAR, either as monotherapy or in combination with PEGV. Soluble Klotho concentrations appear to be a useful marker of QoL in acromegaly patients but the underlying mechanisms remain to be investigated.

Current perspectives on the impact of clinical disease and biochemical control on comorbidities and quality of life in acromegaly

Acromegaly is a rare chronic, systemic disorder caused by excessive growth hormone (GH) secretion from a somatotroph pituitary adenoma. GH hypersecretion leads to overproduction of insulin-like growth factor-1 (IGF-1), which contributes to the somatic overgrowth, physical disfigurement, onset of multiple systemic comorbidities, reduced quality of life (QoL) and premature mortality of uncontrolled patients. Somatostatin receptor ligands, dopamine agonists and a GH receptor antagonist are currently available for medical therapy of acromegaly. The main aim of treatment is biochemical normalisation, defined as age-normalised serum IGF-1 values and random GH levels <1.0 μg/L. However, there is an increasing evidence suggesting that achieving biochemical control does not always decrease the burden of disease-related comorbidities and/or improve patients' QoL. This lack of correlation between biochemical and clinical control can be due to both disease duration (late diagnosis) or to the peculiarity of a given comorbidity. Herein we conducted ad hoc literature searches in order to find the most recent and relevant reports on biochemical and clinical disease control during medical treatment of acromegaly. Particularly, we analyse and describe the relationship between biochemical, as well as clinical disease control in patients with acromegaly receiving medical therapy, with a focus on comorbidities and QoL. In conclusion, we found that current literature data seem to indicate that clinical disease control (besides biochemical control), encompassing clinical signs and symptoms, comorbidities and QoL, emerge as a primary focus of acromegaly patient management.

Sodium Glucose Co-transporter Inhibitors in Patients with Acromegaly and Diabetes

Acromegaly per se predisposes to diabetes. Somatostatin analogs (SSAs) have an overall neutral effect on glycemic control. However, a marked increase in hyperglycemia was observed recently since the introduction of pasireotide long-acting release (PAS-LAR). Sodium glucose cotransporter inhibitors (SGLT2is) have proven their efficacy, cardiovascular safety, and superiority in the management of type 2 diabetes mellitus (T2DM). However, this class is rarely recommended for patients with diabetes and acromegaly. A decreased circulating insulin level is considered unique for this class and might have a beneficial role in the growth hormone-insulin-like growth factor-I (GH-IGF-I) axis. Therefore, SGLT2is should be considered in the management of diabetes in patients with acromegaly. This article highlights the role of this novel class for the management of diabetes in patients with acromegaly.

Somatostatin Analogs and Glucose Metabolism in Acromegaly: A Meta-analysis of Prospective Interventional Studies

INTRODUCTION

Somatostatin analogs (SSAs) effectivelycontrol growth hormone secretion in first and second line treatmentof acromegaly. Their effect onglucose metabolism is still debated.

AIM

to address the following questions: 1) Do SSAs affect fasting plasma glucose (FPG), fasting plasma insulin (FPI), glycosylated hemoglobin (HbA1c), glucose load (2h-OGTT), HOMA-I, HOMA-β, triglycerides (TGD), weight (W) or body mass index (BMI)? 2) Do lanreotide (LAN) and octreotide LAR (OCT) affect metabolism differently? 3)Does their effect depend on disease control?

METHODS

We performed a meta-analysis of prospective interventional trialstreating acromegaly with SSAs. Inclusion criteria: all studies reporting glyco-metabolic outcomes before and after SSAs with a minimum 6-month follow-up.

RESULTS

The inclusion criteria were met by 47 studies treating 1297 subjects (631 F). SSA treatment effectively lowered FPI (effect size [ES] -6.67 mU/L, 95%CI: -8.38 to -4.95mU/L; p<0.001), HOMA-I (ES -1.57, CI: -2.42 to -0.72; p<0.001), HOMA-β (ES -47.45, CI: -73.15 to -21.76; p<0.001) and TGD (ES -0.37 mmol/L, CI: -0.47 to -0.27 mmol/L; p<0.001). SSAs worsened 2h-OGTT (ES 0.59 mmol/L, CI: 0.05 to 1.13 mmol/L; p=0.032), but not FPG. A mild but significant increase in HbA1c (ES 0.12%, CI: 0.00to 0.25%; p=0.044) was found in OCT treated subjects.

CONCLUSIONS

SSA treatment in acromegaly patients-while improving disease control- reduces insulin levels, increases after load glucose and, ultimately, increases HbA1c levels without affecting FPG. The findings suggest that clinicians treating acromegaly with SSAs should consider targeting post-prandial glucose.

Targeting either GH or IGF-I during somatostatin analogue treatment in patients with acromegaly: a randomized multicentre study

CONTEXT

Discordant GH and IGF-I values are frequent in acromegaly. The clinical significance and its dependence on treatment modality and of glucose-suppressed GH (GH_nadir) measurements remain uncertain.

OBJECTIVE

To evaluate the effects of targeting either IGF-I or GH during somatostatin analogue (SA) treatment.

PATIENTS AND METHODS

84 patients with controlled acromegaly after surgery (n = 23) or SA (n = 61) underwent a GH profile including an OGTT, at baseline and after 12 months. SA patients were randomized to monitoring according to either IGF-I (n = 33) or GH_nadir (n = 28). SA dose escalation was allowed at baseline and 6 months.

MAIN OUTCOME MEASURES

GH_nadir and IGF-I at baseline and 12 months, and disease-specific Quality of Life (QoL).

RESULTS

IGF-I and fasting GH levels were comparable between the surgery and the SA group, whereas GH_nadir (µg/L) was lower in the surgery group (GH_nadir 0.7 ± 0.1 vs 0.3 ± 0.1, P < 0.01). SA dose increase was performed in 20 patients in the GH group and in 8 patients in the IGF-I group (P = 0.02), which increased the number of concordantly controlled patients (P = 0.01). QoL was only mildly affected at baseline in all groups and did not changed consistently during the study.

CONCLUSION

(1) Discordant values in terms of high GH levels are prevalent in SA patients and more so if applying glucose-suppressed GH_nadir; (2) targeting discordant levels of either GH or IGF-I translates into SA dose increase and improved biochemical control; (3) even though QoL was not improved in this study, we suggest biochemical assessment of disease activity to include glucose-suppressed GH_nadir also in SA patients.

Biochemical assessment of disease control in acromegaly: reappraisal of the glucose suppression test in somatostatin analogue (SA) treated patients

BACKGROUND

It is recommended not to measure growth hormone during oral glucose suppression (oral glucose tolerance test) during somatostatin analog treatment in acromegaly. However, we have observed that failure to suppress growth hormone in response to oral glucose tolerance test during somatostatin analog unmasks insufficient disease control and hypothesize that somatostatin analog also induces insufficient growth hormone suppression to mixed meals.

METHODS

We therefore compared serum growth hormone levels during two mixed meals in patients with controlled insulin-like growth factor-I levels after either surgery alone (n = 9) or somatostatin analog treatment (n = 9). The patients were unbiasedly matched for gender and insulin-like growth factor-I and studied twice in the following order: (1) during a 6 h growth hormone day curve including two mixed meals and (2) during a 3 h growth hormone profile including 60 min fasting followed by a 2-h oral glucose tolerance test.

RESULTS

During the day curve growth hormone levels were elevated in the somatostatin analog group (P = 0.008) and growth hormone levels 1 h after each meal declined significantly only in the surgery group (P = 0.02). During the oral glucose tolerance test the two groups had similar growth hormone levels prior to the glucose load (P = 0.6), whereas a significant 66% suppression was observed after glucose only in the surgery group (P = 0.001).

CONCLUSIONS

(1) Patients controlled by somatostatin analog fail to suppress growth hormone in response to both mixed meals and oral glucose tolerance test (2) This phenomenon is likely to result in elevated serum growth hormone levels during everyday life in somatostatin analog-treated patients, (3) We postulate that measuring growth hormone levels during oral glucose tolerance test is useful to unmask potential somatostatin analog under-treatment in the presence of 'safe' insulin-like growth factor-I levels.

The ongoing challenge of discrepant growth hormone and insulin-like growth factor I results in the evaluation of treated acromegalic patients: a systematic review and meta-analysis

OBJECTIVE

Growth hormone (GH) and insulin-like growth factor I (IGF-I) are the principal biomarkers used to assess disease activity in acromegaly, and any discrepancy between them renders interpretation of results inconclusive. Purpose of this study was to assess the frequency of this discrepancy and identify parameters that might affect its occurrence.

DESIGN

A systematic review of MEDLINE and Scopus was performed (1987-2013) followed by a meta-analysis to address the frequency of discrepant results between GH and IGF-I levels. Meta-regression and subgroup analyses were performed assessing the effects of the year of publication, the different types of GH testing and GH assays used, as well as the impact of treatment with somatostatin analogues (SSAs) on the occurrence of this discrepancy.

RESULTS

The analysis retrieved 39 eligible studies totalling 7071 patients. The pooled discordance rate between GH and IGF-I was 25·7% (95% CI: 22·3-29·4), and the predominant format was that of elevated IGF-I with normal GH levels (15·3%, 95% CI: 12·5-18·7). No significant correlation between the discordance rate and the year of publication was shown; whereas, the use of ultrasensitive GH assays resulted in higher discordance rates (30·7%, 95% CI: 25·9-35·9 vs 19·8%, 95% CI: 14·1-27·2, P = 0·04) as did treatment with SSAs (32·5%, 95% CI: 27·8-37·4) vs (21·6%, 95% CI: 17·8-25·6, P = 0·001).

CONCLUSIONS

Discrepancy between GH and IGF-I results is encountered in a quarter of treated patients with acromegaly, especially when using ultrasensitive GH assays or in patients receiving SSAs, a fact that the clinician should take into consideration when making clinical decisions.

Three-dimensional soft tissue analysis of the hand: a novel method to investigate effects of acromegaly

Background

Acral overgrowth is a highly common clinical sign in patients with active acromegaly. To what extent this overgrowth persists after long-term remission of acromegaly is largely unknown. Using the new imaging technique of three-dimensional (3D) stereophotogrammetry, it is possible to accurately investigate soft tissue changes of the hand. The aim of the recent study was to compare the 3D soft tissue characteristics of the hands of patients in long-term remission of acromegaly to those of a healthy pair matched control group.

Methods

A case-control study was performed at a tertiary referral center. Twelve patients in remission of acromegaly (58 % male, mean age 58.3 years, mean BMI 29.6 kg/m²) were compared to twelve age-, gender-, ethnicity-, and BMI-matched control subjects. Of each individual, 3D photographs of both hands were acquired and analyzed using a 3D computer software program.

Results

The patients in long-term remission of acromegaly have overgrowth of soft tissue of the hand compared to matched control subjects, with a larger length and width of the hand (p = 0.0025, p = 0.0017, respectively). Furthermore, the diameters measured at the proximal interphalangeal (PIP) joints of the individual fingers are larger in the acromegaly patients.

Conclusions

Significant soft tissue overgrowth of the hand persists in former acromegaly patients, even after long-term remission. Analysis of 3D hand photographs is an accurate and easy tool to evaluate the acral soft tissue patterns in acromegaly.

Level of Evidence: Level III, diagnostic study.

Combined treatment of somatostatin analogues with pegvisomant in acromegaly

Treatment of acromegaly with monotherapy long-acting somatostatin analogues (LA-SSA) as primary treatment or after neurosurgery can only achieve complete normalization of insulin-like growth factor I (IGF-I) in roughly 40 % of patients. Recently, one of the acromegaly consensus groups has recommended switching to combined treatment of LA-SSA and pegvisomant (PEGV) in patients with partial response to LA-SSAs. This combination of LA-SSA and PEGV, a growth hormone receptor antagonist, can normalize IGF-I levels in virtually all patients, requiring that the adequate dose of PEGV is used. The required PEGV dose varies significantly between individual acromegaly patients. One of the advantages of the combination therapy is that tumor size control or even tumor shrinkage can be observed in a vast majority of patients. The main side effects of the combination treatment are gastrointestinal symptoms, lipohypertrophy and transient elevated liver transaminases. In this review we provide an overview of the efficacy and safety of the combined treatment of LA-SSAs with PEGV.

The Impact of Adipose Tissue on Insulin Resistance in Acromegaly

Adipose tissue (AT) is recognized as key contributor to the systemic insulin resistance and overt diabetes seen in metabolic syndrome. Acromegaly is a disease characterized by excessive secretion of growth hormone (GH) and insulin-like growth factor I (IGF-I). GH is known both for its action on AT and for its detrimental effect on glucose metabolism and insulin signaling. In active acromegaly, while body fat deports are diminished, insulin resistance is increased. Early studies have demonstrated defects in insulin action, both at the hepatic and extrahepatic (i.e., muscle and fat) levels, in active disease. This review discusses recent data suggesting that AT inflammation, altered AT distribution, and impaired adipogenesis are potential mechanisms contributing to systemic insulin resistance in acromegaly.

Pegvisomant Treatment in Acromegaly

Historically, medical treatment of acromegaly has mainly been used as an adjuvant therapy after surgery. In the last decades, an increased range of medical therapy options has been available. Somatostatin analogues have become the cornerstones of medical treatment in acromegaly and are even seen as a primary treatment in a selected group of acromegaly patients. The most recent medical treatment available for acromegaly patients is pegvisomant, a growth hormone receptor antagonist. To date, it is the most effective medical treatment, but it is costly. Pegvisomant is used as monotherapy and combined with somatostatin analogues. In this article, we review clinical studies and cohorts that have documented the efficacy of pegvisomant monotherapy and combined therapy and give a concise overview of associated side effects.

The Metabolic Risk in Patients Newly Diagnosed with Acromegaly Is Related to Fat Distribution and Circulating Adipokines and Improves after Treatment

BACKGROUND/AIMS

Adipose tissue (AT) distribution is closely related to metabolic disease risk. Growth hormone (GH) reduces visceral and total body fat mass and induces whole-body insulin resistance. Our aim was to assess the effects of total and visceral AT (VAT) distribution and derived adipokines on systemic insulin resistance and lipid metabolism in acromegaly.

METHODS

Seventy adult patients with active acromegaly (43 males, age 49 ± 14 years) were evaluated before treatment, and a subset (n = 30, 20 males) was evaluated after treatment for acromegaly. Body composition and VAT, glucose metabolism parameters, lipids, C-reactive protein, and selected adipokines (vaspin, omentin, adiponectin, and leptin) were measured.

RESULTS

At baseline, VAT was positively associated with glucose metabolism parameters and with lipids. GH, but not IGF-I, was negatively associated with all AT depots (visceral, trunk, limbs, and total; 0.41 ≤ r ≤ 0.61, p < 0.001 for all) and positively associated with vaspin (r = 0.31, p = 0.013). The fat deposition after treatment was predominantly located on trunk and visceral depots. The lipid profile partially improved, with increases in HDL and apolipoprotein A-I and a decrease in lipoprotein(a). Vaspin decreased and omentin increased. Adiponectin and leptin did not change significantly. The improvement in homeostasis model assessment for insulin resistance (HOMA-IR) was best predicted by the decreases in IGF-I and vaspin and the lack of an increase in trunk fat (R2 = 0.59, p = 0.001).

CONCLUSIONS

(1) VAT is a metabolic risk factor for patients with active acromegaly; (2) vaspin and omentin levels are influenced by the disease activity but are not associated with VAT mass; (3) fat deposition after treatment occurs predominantly on the trunk and in visceral depots, and (4) insulin resistance decreases and the lipid profile partially improves with treatment.

Disease control and treatment modalities have impact on quality of life in acromegaly evaluated by Acromegaly Quality of Life (AcroQoL) Questionnaire

Various factors influence quality of life (QoL) in acromegaly. Whether disease control and treatment approach are related to QoL is still a matter of debate. The aim of the present study was to evaluate QoL in patients with acromegaly using the disease-specific Acromegaly Quality of Life Questionnaire in respect to disease activity, treatment modalities, and other factors. We studied 212 patients with acromegaly in a cross-sectional manner over a 6-year period in a single tertiary center. As a second step, seventy of the patients who were with active disease at baseline were followed up prospectively and 45 of them were in remission at re-evaluation. In regard to the cross-sectional group, active acromegaly independently predicted worse appearance scores. Prior radiotherapy and older age were independent negative predictors of all scales. Female gender negatively predicted all scales except the appearance domain. Longer duration of remission predicted worse personal relations scores in biochemically controlled patients. The use of somatostatin analog (SSA) was associated with worse personal relations scores, while higher IGF-1 index predicted worse appearance scores in patients with active acromegaly. In the prospective group, achievement of remission independently predicted improvement of the total scale. Lower corresponding baseline scores predicted improvement of the total, physical, and appearance scales, while the absence of hypopituitarism independently predicted improvement of the appearance scale. The use of SSA was associated with improvement of the total and appearance scores. In conclusion, QoL is a multifactorial issue that needs an individualized approach for detection and management.

Discordance between growth hormone and insulin-like growth factor-1 after pituitary surgery for acromegaly: a stepwise approach and management

INTRODUCTION

Follow-up management of patients with acromegaly after pituitary surgery is performed by conducting biochemical assays of growth hormone (GH) and insulin-like growth factor-1 (IGF1). Despite concordant results of these two tests in the majority of cases, there is increasing recognition of patients who show persistent or intermittent discordance between GH and IGF1 (normal GH and elevated IGF1 or vice versa).

METHOD

In this narrative review, the last three decades materials on the issue of discrepancy between GH and IGF1 were thoroughly assessed.

RESULTS

Various studies have obtained different discordance rates, ranging from 5.4 to 39.5%. At present, despite the use of current sensitive assays and more stringent criteria to define remission, the rate of discordance still remains high. A number of mechanisms have been proposed to explain the postoperative discordance of GH and IGF1 including; altered dynamics of the GH secretion after surgery, early postoperative hormone assay, inaccurate or less sensitive tests and laboratory errors, too high cut-off point for GH suppression in the GH assays, GH nadir values not adjusted to age, sex, and body mass index, the influence of concomitant medication, co-existing physiologic and pathologic conditions, and many other proposed reasons. Nevertheless, the underlying mechanisms are still far from clear, and the solution continues to evade complete elucidation. Similarly, the impacts of such a discrepancy over mortality and morbidity and the risk of biochemical and/or clinical recurrence are unclear.

CONCLUSION

As a challenging clinical problem, a stepwise evaluation and management of these patients appears to be more rational.

Escape and lipodystrophy in acromegaly during pegvisomant therapy, a retrospective multicentre Spanish study

BACKGROUND

Pegvisomant is an effective treatment for acromegaly.

OBJECTIVE

To investigate escape (loss of biochemical control in patients previously controlled) and lipodystrophy in acromegalic patients treated with pegvisomant and to evaluate possible associations with clinical features.

PATIENTS AND METHODS

Multicentre retrospective study involving 19 Spanish centres.

RESULTS

Ninety-seven patients were included (59% women, mean age at diagnosis 42 ± 13 years, 80% macroadenomas); mean follow-up on pegvisomant was 5 ± 2·5 years, and 89 (92%) achieved normal IGF-1. Escape was reported in 30/89 (34%) of responders, after a mean treatment duration of 25 ± 21 months. The mean initial dose of pegvisomant was 11 ± 5 mg/day, and mean dose at escape was 14 ± 7 mg/day. Most patients (26/30, 87%) achieved control with dose increase (57%), additional medical treatment (3%) or both (27%). Mean new dose that controlled IGF-1 after escape was 20 ± 7 mg/day. Treatments associated were somatostatin analogues (SSA in 47%), cabergoline (CAB in 47%) and both (6%). Lipodystrophy was observed in 15 patients (13 females), mild in six, moderate in six, severe in three and persistent in four. Among patients with lipodystrophy, three escaped and three were nonresponders to pegvisomant. Four patients discontinued the drug, and four had dose reductions because of lipodystrophy. It tended to be more frequent in females (P = 0·06) and in patients treated with triple association SSA+CAB+PEG (P = 0·018). No relationship between escape and clinical variables was found, except prior CAB (P = 0·04) and metformin treatment (0·02) and grade of lipodystrophy (P = 0·02).

CONCLUSIONS

A significant proportion of patients treated with pegvisomant escaped (34%); however, the majority (87%) was easily controlled with either dose increase, further medical treatment or both. Lipodystrophy developed in 15%, mostly females, and influenced the response to treatment.

Therapy of acromegalic patients exacerbated by concomitant type 2 diabetes requires higher pegvisomant doses to normalise IGF1 levels

OBJECTIVE

Acromegaly is associated with an increased prevalence of glucose metabolism disorders. Clinically confirmed diabetes mellitus is observed in approximately one quarter of all patients with acromegaly and is known to have a worse prognosis in these patients.

DESIGN

Of 514 acromegalic patients treated with pegvisomant and recorded in the German Cohort of ACROSTUDY, 147 had concomitant diabetes mellitus. We analysed these patients in an observational study and compared patients with and without concomitant diabetes.

RESULTS

Under treatment with pegvisomant, patients with diabetes mellitus rarely achieved normalisation (64% in the diabetic cohort vs 75% in the non-diabetic cohort, P=0.04) for IGF1. Diabetic patients normalised for IGF1 required higher pegvisomant doses (18.9 vs 15.5 mg pegvisomant/day, P<0.01). Furthermore, those diabetic patients requiring insulin therapy showed a tendency towards requiring even higher pegvisomant doses to normalise IGF1 values than diabetic patients receiving only oral treatment (22.8 vs 17.2 mg pegvisomant/day, P=0.11).

CONCLUSIONS

Hence, notable interdependences between the acromegaly, the glucose metabolism of predisposed patients and their treatment with pegvisomant were observed. Our data support recent findings suggesting that intra-portal insulin levels determine the GH receptor expression in the liver underlined by the fact that patients with concomitant diabetes mellitus, in particular those receiving insulin therapy, require higher pegvisomant doses to normalise IGF1. It is therefore important to analyse various therapy modalities to find out whether they influence the associated diabetes mellitus and/or whether the presence of diabetes mellitus influences the treatment results of an acromegaly therapy.

Management of endocrine disease: GH excess: diagnosis and medical therapy

Acromegaly is predominantly caused by a pituitary adenoma, which secretes an excess of GH resulting in increased IGF1 levels. Most of the GH assays used currently measure only the levels of the 22 kDa form of GH. In theory, the diagnostic sensitivity may be lower compared with the previous assays, which have used polyclonal antibodies. Many GH-secreting adenomas are plurihormonal and may co-secrete prolactin, TSH and α-subunit. Hyperprolactinaemia is found in 30-40% of patients with acromegaly, and hyperprolactinaemia may occasionally be diagnosed before acromegaly is apparent. Although trans-sphenoidal surgery of a GH-secreting adenoma remains the first treatment at most centres, the role of somatostatin analogues, octreotide long-acting repeatable and lanreotide Autogel as primary therapy is still the subject of some debate. Although the normalisation of GH and IGF1 levels is the main objective in all patients with acromegaly, GH and IGF1 levels may be discordant, especially during somatostatin analogue therapy. This discordance usually takes the form of high GH levels and an IGF1 level towards the upper limit of the normal range. Pasireotide, a new somatostatin analogue, may be more efficacious in some patients, but the drug has not yet been registered for acromegaly. Papers published on pasireotide have reported an increased risk of diabetes mellitus due to a reduction in insulin levels. Pegvisomant, the GH receptor antagonist, is indicated - alone or in combination with a somatostatin analogue - in most patients who fail to enter remission on a somatostatin analogue. Dopamine-D2-agonists may be effective as monotherapy in a few patients, but it may prove necessary to apply combination therapy involving a somatostatin analogue and/or pegvisomant.

Comparison of the effects of primary somatostatin analogue therapy and pituitary adenomectomy on survival in patients with acromegaly: a retrospective cohort study

OBJECTIVE

Acromegalic patients have an increased risk of mortality. The objective of this study was to compare the effect of different therapies for acromegaly on mortality.

DESIGN AND METHODS

The mortality rate of 438 consecutive acromegalic patients was compared with that of the general population using the standardized mortality ratio (SMR); the effect of different therapies on survival was evaluated using Cox regression analysis.

RESULTS

Twenty patients (4.5%) died between 1999 and 2009. Age- and sex-adjusted SMR was 0.70 (95% CI 0.43-1.08). The Cox regression analysis revealed that, in the whole population, both general risk factors (age and physical status) and specific factors for acromegaly (macroadenoma, hypopituitarism and uncontrolled disease) were associated with death. The most compromised patients at diagnosis had a higher mortality rate (P=0.001), which also occurred in patients with controlled acromegaly. Death occurred in 2.4% (adenomectomy), 2.6% (adenomectomy followed by somatostatin analogue (SSA) therapy) and 11.4% (SSA therapy as the primary therapy) of the patients. The risk of death was higher in patients receiving SSA therapy as the primary therapy (hazard ratio (HR) 5.52, 95% CI 1.06-28.77, P=0.043) than in all patients submitted to adenomectomy; however, a higher risk of death occurred only in diabetic patients treated with SSAs alone (HR 21.94, 95% CI 1.56-309.04, P=0.022). Radiotherapy was associated with an increased risk of mortality, which occurred in patients with the more locally advanced disease.

CONCLUSIONS

Therapies for acromegaly and comorbidities have lowered the risk of mortality to the level of the general population; the effect of SSA therapy alone or that following pituitary adenomectomy was comparable to that of curative neurosurgery on survival in non-diabetic patients; on the contrary, SSA therapy as the primary therapy may be less effective than adenomectomy in reducing mortality rate in diabetic patients.

Extra-hepatic Acromegaly

After the introduction of somatostatin analogs (LA-SMSA) and the growth hormone (GH) receptor antagonist, pegvisomant (Peg-v) normal serum insulin-like growth factor-1 (IGF-1) concentrations in virtually every patients with acromegaly is possible. The impact of these products on the GH-IGF1 axis is completely different. We advocate that LA-SMSA may normalize serum IGF1 levels in the presence of elevated GH actions in extra-hepatic tissues. This results in persistent peripheral disease activity that we call 'extra-hepatic acromegaly'. Peg-v competitively blocks systemic GH action and results in a GH serum level increase. Therefore high doses of Peg-v are necessary to control IGF-1. Since the mode of action differs between these products, it is questionable if identical IGF-1 levels, during Peg-v or LA-SMSA are really identical representations of the biochemical situation. With the traditional biomarkers medical treatment is therefore difficult to monitor with the traditional biomarkers. Additionally, Peg-v and LA-SMSA could be ideal combination since they have different mode of actions. We believe that the time has come to challenge the existing concepts of treatment and monitoring of patients with acromegaly.

Effects of previous growth hormone excess and current medical treatment for acromegaly on cognition

BACKGROUND

In untreated acromegaly patients, decreased cognitive functioning is reported to be associated with the degree of growth hormone (GH) and IGF-1 excess. Whether previous GH excess or current medical treatment for acromegaly specifically affects cognition remains unclear. The aim of this study was to compare cognitive functioning of patients who are treated for acromegaly with patients with non-functioning pituitary adenomas (NFA). In addition, we assessed the influence of prolonged medical treatment after initial transsphenoidal surgery on cognition.

DESIGN

In this cross-sectional study, 74 patients participated, who were treated for acromegaly (n = 50; median [interquartile range] age: 53 [45-65] years) or NFA (n = 24; age: 63 [59-70] years). The NFA patients were selected for a high likelihood of normal GH secretion based on an IGF-1 z-score within the normal range (> -2) and zero or one axis substituted. Of the acromegaly patients, 28 had achieved remission, while 22 were biochemically controlled with long-acting somatostatin analogues and/or pegvisomant. Memory and executive functioning were assessed by the 15 Words Test and the Ruff Figural Fluency Test, and reported as z-scores.

RESULTS

The total patient group scored significantly poorer than the reference population on memory and executive functioning (P < 0·001). However, cognitive test performance was not significantly different between acromegaly patients with a persistent disease, acromegaly patients in remission and NFA patients.

CONCLUSION

The total patient group scored worse compared with reference populations. We found no association between previous GH excess and cognition. In addition, current medical treatment for GH excess in acromegaly was not related to memory and executive functioning.

Italian Society of Endocrinology Career Award Lecture: from somatostatin to…somatomedin

Somatostatin plays different parts in hormonal regulation through 5 specific receptors in human body. It has two interesting actions such as an antisecretory activity, mostly on the gastrointestinal system and pituitary level, and an antiproliferative action on tumor cells. Many synthetic somatostatin analogues, more stable than the natural one, have been developed and two are already used in different clinical settings, including endocrine oncology. The inhibitory action on tumor growth may result from both indirect actions, namely the suppression of growth factors and growth-promoting hormones (e.g., GH/IGF-I axis) and inhibition of angiogenesis, as well as modulation of the immune system, and direct actions, such as activation of anti-growth activities (e.g., apoptosis). Recently, the development of specific polyclonal antibodies allowed the precise identification of the 5 specific somatostatin receptors and their localization in different cell species. Somatostatin receptor subtypes belong to the G protein-coupled receptor family, share a common molecular topology, and can traffic not only in vitro within different cell types but also in vivo. A picture of the pathways and proteins involved in these processes is beginning to emerge. Moreover, the process of homo- and/or heterodimerization of G-protein coupled receptors and receptor tyrosine kinase families are crucial for implicating the fundamental properties of receptor proteins including receptor expression, trafficking, and desensitization, as well as signal transduction. Furthermore, functional consequences of such an interaction in modulation of signaling pathways linked to pathological conditions specifically in cancer are discussed.

Pathophysiology of renal calcium handling in acromegaly: what lies behind hypercalciuria?

BACKGROUND

Hypercalciuria is frequent in patients with acromegaly, but it is unclear how GH/IGF-I regulate renal calcium handling. Elevated fasting plasma calcium levels despite increased glomerular filtration suggest enhanced renal calcium reabsorption.

OBJECTIVE

The aim of this study was to investigate the impact of acromegaly on phosphocalcium metabolism.

DESIGN AND SETTING

We conducted a prospective sequential study at a tertiary referral medical center and clinical investigation center (www.ClinicalTrials.gov Identifier: NCT00531908).

INTERVENTION

Sixteen consecutive patients (five females/11 males) with acromegaly received a single iv infusion of 25 mg of furosemide to induce an acute increase in calcium and magnesium delivery to distal tubular segments during a high-sodium diet with stable dietary calcium, magnesium, and phosphate intake.

MEASUREMENTS

Baseline plasma and urine electrolytes, plasma calciotropic hormones, and furosemide-induced changes in the fractional excretion and tubular reabsorption of Na, Ca, and Mg were measured before and 6 months (range, 1-12) after effective treatment of acromegaly.

RESULTS

Serum IGF-I concentrations normalized in all the patients after acromegaly treatment. Compared with controlled acromegaly, active acromegaly was associated with higher fasting plasma (P = 0.0002) and urinary calcium (P = 0.0003) levels, lower PTH levels (P = 0.0075), higher calcitriol levels (P = 0.0137), higher phosphatemia (P<0.0001) and tubular phosphate reabsorption (P = 0.0002), and a lower calciuric (P = 0.0327) but not magnesiuric response to furosemide related to higher baseline and postfurosemide tubular calcium (P = 0.0034 and P = 0.0081, respectively), but not magnesium reabsorption.

CONCLUSION

The IGF-I-mediated and PTH-independent increase in calcitriol synthesis in acromegaly is responsible for both absorptive hypercalciuria and increased fasting plasma calcium linked to enhanced distal tubular calcium reabsorption, as shown by the selectively diminished calciuric response to furosemide.

Octreotide long-acting repeatable for acromegaly

Acromegaly remains a therapeutic challenge for the endocrinologist. Among the available therapeutic options, octreotide long-acting repeatable (Sandostatin(®) LAR(®), Novartis) plays a chief role, both as a primary therapy and as an adjuvant treatment after unsuccessful surgery. A plethora of papers and a meta-analysis have demonstrated its efficacy in: control of clinical picture; achievement of safe growth hormone and normal age-matched IGF-I levels (both factors associated with restoration of normal life expectancy) in 60-70% of patients; control of tumor volume (with real shrinkage in over half of cases); and halt or reversal of most acromegaly-associated comorbidities. Treatment is well tolerated in most patients and can be safely prolonged for many years if required.

What is active acromegaly and which parameters do we have?

Disease activity of acromegaly can be measured in many ways. Growth hormone (GH) and insulin-like growth factor 1 (IGF1) concentrations are the main biochemical markers used to measure the response to treatment. Both GH and IGF1 have been associated with prognosis, in particular mortality. In this review, we discuss the available parameters to assess disease activity in acromegaly.

Quality of life is impaired in association with the need for prolonged postoperative therapy by somatostatin analogs in patients with acromegaly

OBJECTIVE

To assess the influence of long-acting somatostatin analogs (SSTA) after initial pituitary surgery on long-term health-related quality of life (HR-QoL) in relation to disease control in patients with acromegaly.

DESIGN

This is a cross-sectional study in two tertiary referral centers in The Netherlands.

PATIENTS AND METHODS

One hundred and eight patients with acromegaly, in whom transsphenoidal (n=101, 94%) or transcranial (n=7, 6%) surgery was performed. Subsequently, 46 (43%) received additional radiotherapy and 41 (38%) were on postoperative treatment with SSTA because of persistent or recurrent disease at the time of study. All subjects filled in standardized questionnaires measuring HR-QoL. Disease control at the time of study was assessed by local IGF1 SDS.

RESULTS

IGF1 SDS were slightly higher in patients treated with SSTA in comparison with patients without use of SSTA (0.85±1.52 vs 0.25±1.21, P=0.026), but the percentage of patients with insufficient control (IGF1 SDS >2) was not different (17 vs 9%, P=0.208). Patients using SSTA reported poorer scores on most subscales of the RAND-36 and the acromegaly QoL and on all subscales of the multidimensional fatigue inventory-20. A subgroup analysis in patients with similar IGF1 levels (SSTA+, n=26, IGF1 SDS 0.44±0.72 vs SSTA-, n=44, IGF1 SDS 0.41±0.65) revealed worse scores on physical functioning, physical fatigue, reduced activity, vitality, and general health perception across all HR-QoL questionnaires in patients treated with SSTA.

CONCLUSION

QoL is impaired in association with the need for prolonged postoperative therapy by SSTA in patients with acromegaly despite similar IGF1 levels.

Medical therapy of acromegaly

This paper outlines the present status of medical therapy of acromegaly. Indications for permanent postoperative treatment, postirradiation treamtent to bridge the interval until remission as well as primary medical therapy are elaborated. Therapeutic efficacy of the different available drugs-somatostatin receptor ligands (SRLs), dopamine agonists, and the GH antagonist Pegvisomant-is discussed, as are the indications for and efficacy of their respective combinations. Information on their mechanism of action, and some pharmakokinetic data are included. Special emphasis is given to the difficulties to define remission criteria of acromegaly due to technical assay problems. An algorithm for medical therapy in acromegaly is provided.

Combination treatment with somatostatin analogues and pegvisomant in acromegaly

Mono-therapy using long-acting somatostatin analogues and surgery cannot provide optimal biochemical control in a large proportion of patients with acromegaly. This results in increased mortality, poor control of signs and symptoms of disease and decreased quality of life. Combined treatment with somatostatin analogues and pegvisomant (a growth-hormone-receptor antagonist) seems to be an attractive option. Combination treatment is highly effective at normalising the level of insulin-like growth factor 1 in over 90% of patients and has a favourable effect on quality of life in those with biochemically controlled acromegaly. Moreover, combination therapy with somatostatin analogues results in a clinically relevant decrease in tumour size in about 20% of patients, whereas pegvisomant (PEG-V) mono-therapy does not decrease pituitary tumour size. Transient elevations in the levels of transaminases are the main adverse effects of combination treatment, which occur in about 11-15% of patients.

[Growth hormone receptor antagonist in the treatment of acromegaly]

Exploration of construction, function and interaction of human growth hormone and growth hormone receptor in details resulted in the innovation of the new growth hormone receptor antagonist, pegvisomant. Pegvisomant with different mechanism of action extended the tools of medical management of acromegaly. Importance of the novel treatment modality is high. In one hand the necessity of the strict control of growth hormone/insulin-like growth factor-I axis has been proven regarding the mortality of the disease. On the other hand, despite the use of all current modes of treatment (surgery, radiotherapy, dopamine agonists, somatostatin analogs), a significant cohort of patients with acromegaly remains inadequately controlled. Pegvisomant has been registered in 2004. Since 2006, it has been used in Hungary for the treatment of acromegaly in patients who have had an inadequate response to surgery and/or radiation therapy and/or other medical therapies, or for whom these therapies are not appropriate. Clinical use of pegvisomant in the treatment of acromegaly is effective, well tolerated, and safe, based on international Acrostudy database. In order to improve the efficacy of therapy clinical trials started with pegvisomant and somatostatin analog combination treatment. Evidence of several further effects of the growth hormone/insulin-like growth factor-I axis suggests other potential uses of growth hormone receptor antagonists.