Use of lanreotide in combination with cabergoline or pegvisomant in patients with acromegaly in the clinical practice: The ACROCOMB study

Investigational drugs for the treatment of acromegaly: new agents to transform therapy

INTRODUCTION

Disease control is essential to decrease morbidity burden and mortality in acromegaly patients. In the last decades, the availability of new drugs increased the rate of disease control. However, up to 55% of patients remain uncontrolled despite available treatment strategies in real-world data. The reasons for this finding may include poor adherence, inadequate tolerability, therapeutic inertia, and high costs. Since acromegaly is a chronic disease and medical therapy is usually life-long, patient's adherence to treatment is fundamental in both achieving and maintaining disease control. Less invasive routes of administration could improve adherence and concur to increase disease control rate.

AREAS COVERED

The aim of current review is to provide a detailed update about investigational drugs for acromegaly treatment currently under investigation as paltusotine, ONO-5788, AP102, GT-02037, ISIS 766720, CAM2024, Lanreotide PRF, DP1038, MTD201, solid dose injection of octreotide.

EXPERT OPINION

Medical therapy of acromegaly is an evolving field. Current studies are addressing patient's need for both new molecules and less invasive routes of administration for already existing drugs. It cannot be ruled out that drugs currently used for other diseases such as cancer could be considered in the future for the treatment of acromegaly.

Oral Octreotide Capsules and Paltusotine in Management of Acromegaly

Injectable somatostatin receptor ligands (iSRL) are the most frequently utilized medical therapy in patients with acromegaly; however, satisfaction rates are suboptimal. Injections can result in local erythema, discomfort and subcutaneous nodule formation, encompassed with the inconvenience of attending either primary or secondary care medical facilities for injections every 4 weeks. Some patients also note breakthrough of acromegaly-related symptoms towards the end of the injection cycle. To improve acceptance and ultimately improve wellbeing of these individuals, two oral SRLs, oral octreotide capsules (OOC) and paltusotine, have been developed. The OOC combines an enteric coating to allow delivery to the small intestines and a transient permeability enhancer to enable oral bioavailability. Comparable octreotide levels are obtained with twice-daily OOC and subcutaneous octreotide 100 µg. Phase III studies show OOC to maintain equivalent biochemical control in at least 60% of patients previously receiving a stable dose of iSRL. In longer-term studies, the response to OOC was durable up to 3 years. Paltusotine is a novel potent orally available non-peptidyl somatostatin receptor subtype-2 ligand. Studies in healthy volunteers show dose-dependent suppression of growth hormone-releasing hormone-induced growth hormone secretion and suppression of insulin-like growth factor-I (IGF-I) with repeat doses. In the recent phase II study, patients with acromegaly who were partial responders (IGF-I 1.0 - 2.5 x upper limit of normal) to monotherapy with iSRL when switched to once-daily paltusotine maintained control of IGF-I within 20% of baseline or lower in 87% after 13 weeks. Adverse events with both OOC and paltusotine were reflective of those recognized with iSRL and occurred at a similar frequency. OOC and paltusotine are well-received additions to the therapeutic armamentarium in medical therapy for the management of acromegaly; however, further data on efficacy, tumour control and shrinkage are required to allow positioning of this medication within the management algorithm for acromegaly.

Integrative Clinical, Radiological, and Molecular Analysis for Predicting Remission and Recurrence of Cushing Disease

CONTEXT

Adrenocorticotropin (ACTH)-secreting pituitary tumors (ACTHomas) are associated with severe comorbidities and increased mortality. Current treatments mainly focus on remission and prevention of persistent disease and recurrence. However, there are still no useful biomarkers to accurately predict the clinical outcome after surgery, long-term remission, or disease relapse.

OBJECTIVES

This work aimed to identify clinical, biochemical, and molecular markers for predicting long-term clinical outcome and remission in ACTHomas.

METHODS

A retrospective multicenter study was performed with 60 ACTHomas patients diagnosed between 2004 and 2018 with at least 2 years' follow-up. Clinical/biochemical variables were evaluated yearly. Molecular expression profile of the somatostatin/ghrelin/dopamine regulatory systems components and of key pituitary factors and proliferation markers were evaluated in tumor samples after the first surgery.

RESULTS

Clinical variables including tumor size, time until diagnosis/first surgery, serum prolactin, and postsurgery cortisol levels were associated with tumor remission and relapsed disease. The molecular markers analyzed were distinctly expressed in ACTHomas, with some components (ie, SSTR1, CRHR1, and MKI67) showing instructive associations with recurrence and/or remission. Notably, an integrative model including selected clinical variables (tumor size/postsurgery serum cortisol), and molecular markers (SSTR1/CRHR1) can accurately predict the clinical evolution and remission of patients with ACTHomas, generating a receiver operating characteristic curve with an area under the curve of 1 (P < .001).

CONCLUSION

This study demonstrates that the combination of a set of clinical and molecular biomarkers in ACTHomas is able to accurately predict the clinical evolution and remission of patients. Consequently, the postsurgery molecular profile represents a valuable tool for clinical evaluation and follow-up of patients with ACTHomas.

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.

Multicenter, Observational Study of Lanreotide Autogel for the Treatment of Patients with Acromegaly in Routine Clinical Practice in Germany, Austria and Switzerland

BACKGROUND

Evidence from controlled trials has shown that lanreotide autogel is effective in achieving biochemical and symptom control in patients with acromegaly. However, it is important to better understand the real-world patient population receiving lanreotide autogel treatment.

METHODS

In this non-interventional study the long-term treatment response to lanreotide autogel in adult patients with acromegaly from office-based centers or clinics in Germany, Austria and Switzerland was studied. Assessments included growth hormone and insulin-like growth factor-I levels, symptoms, quality of life, lanreotide plasma levels and tumor somatostatin receptor subtype expression. The primary endpoint was achievement of full biochemical control, defined as growth hormone ≤2.5 µg/L and insulin-like growth factor I normalization at month 12.

RESULTS

76 patients were enrolled from 21 sites. 7/51 (13.7%) patients of the efficacy population had full biochemical control at baseline, 15/33 (45.5%) at month 12 and 10/26 (38.5%) at month 24 of treatment. At 12 months of treatment higher rates of biochemical control were observed in the following subgroups: older patients (>53 years [median]), females, treatment-naïve patients, and patients with a time since diagnosis of longer than 1.4 years (median). No clinically relevant differences in acromegaly symptoms or quality of life scores were observed. Median fasting blood glucose and glycated hemoglobin levels remained unchanged throughout the study. No new safety signals were observed. Overall tolerability of treatment with lanreotide autogel was judged by 80.8% of the enrolled patients at month 12 as 'very good' or 'good'.

CONCLUSION

Treatment with lanreotide autogel in a real-world setting showed long-term effectiveness and good tolerability in patients with acromegaly.

Surgical and Pharmacological Outcomes in Acromegaly: Real-Life Data From the Mexican Acromegaly Registry

CONTEXT

Acromegaly registries constitute a valuable source of therapeutic outcome information in real-life.

OBJECTIVE

The objective of this work is to analyze surgical and pharmacological outcomes in the Mexican Acromegaly Registry (MAR).

DESIGN AND METHODS

Data were extracted from the MAR informatic platform. Surgical remission was defined by a postoperative postglucose (GH) of less than 1 ng/mL and an insulin-like growth factor 1 (IGF-1) of less than 1.2 × upper limit of normal (ULN). Pharmacological remission was defined by a basal GH of less than 1 ng/mL and an IGF-1 of less than 1.2 × ULN.

RESULTS

A total of 650 surgical outcomes were analyzed (94.6% transsphenoidal). Surgical remission was achieved in 40.15%, whereas 44.15% remained biochemically active. Persistently active disease after surgery was significantly associated with harboring an invasive macroadenoma, a basal GH of greater than 10 ng/mL, and/or an IGF-1 of greater than 2 × ULN at diagnosis on bivariate and multivariate analysis. The outcome of monotherapy with first-generation somatostatin analogs (SSAs) was evaluated in 267 patients (adjunctive in 65%), of whom 28.4% achieved remission. Persistently active disease was significantly associated with harboring an invasive macroadenoma as well as with pretreatment basal GH and IGF-1 levels of greater than 10 ng/mL and greater than 2 × ULN, respectively, on bivariate and multivariate analysis. Combined therapy with SSA and cabergoline was analyzed in 100 patients, of whom 19% achieved remission and 44% remained active; in this subset of patients, only a pretreatment IGF-1 of greater than 2 × ULN was significantly associated with persistent disease activity.

CONCLUSION

Surgical and pharmacological outcomes in acromegaly are highly dependent on tumor size/invasiveness as well as on the degree of hypersomatotropinemia.

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.

Statins Directly Regulate Pituitary Cell Function and Exert Antitumor Effects in Pituitary Tumors

INTRODUCTION

Pituitary neuroendocrine tumors (PitNETs), the most abundant of all intracranial tumors, entail severe comorbidities. First-line therapy is transsphenoidal surgery, but subsequent pharmacological therapy is often required. Unfortunately, many patients are/become unresponsive to available drugs (somatostatin analogues [SSAs]/dopamine agonists), underscoring the need for new therapies. Statins are well-known drugs commonly prescribed to treat hyperlipidemia/cardiovascular diseases, but can convey additional beneficial effects, including antitumor actions. The direct effects of statins on normal human pituitary or PitNETs are poorly known. Thus, we aimed to explore the direct effects of statins, especially simvastatin, on key functional parameters in normal and tumoral pituitary cells, and to evaluate the combined effects of simvastatin with metformin (MF) or SSAs.

METHODS

Effects of statins in cell proliferation/viability, hormone secretion, and signaling pathways were evaluated in normal pituitary cells from a primate model (Papio anubis), tumor cells from corticotropinomas, somatotropinomas, nonfunctioning pituitary tumors, and PitNET cell-lines (AtT20/GH3-cells).

RESULTS

All statins decreased AtT20-cell proliferation, simvastatin showing stronger effects. Indeed, simvastatin reduced cell viability and/or hormone secretion in all PitNETs subtypes and cell-lines, and ACTH/GH/PRL/FSH/LH secretion (but not expression), in primate cell cultures, by modulating MAPK/PI3K/mTOR pathways and expression of key receptors (GH-releasing hormone-receptor/ghrelin-R/Kiss1-R) regulating pituitary function. Addition of MF or SSAs did not enhance simvastatin antitumor effects.

CONCLUSION

Our data reveal direct antitumor effects of simvastatin on PitNET-cells, paving the way to explore these compounds as a possible tool to treat PitNETs.

Biguanides Exert Antitumoral Actions in Pituitary Tumor Cells Through AMPK-Dependent and -Independent Mechanisms

CONTEXT

Pituitary neuroendocrine tumors (PitNETs) are a commonly underestimated pathology in terms of incidence and associated morbimortality. Currently, an appreciable subset of patients are resistant or poorly responsive to the main current medical treatments [i.e., synthetic somatostatin analogs (SSAs) and dopamine agonists]. Thus, development and optimization of novel and available medical therapies is necessary. Biguanides (metformin, buformin, and phenformin) are antidiabetic drugs that exert antitumoral actions in several tumor types, but their pharmacological effects on PitNETs are poorly known.

OBJECTIVE

We aimed to explore the direct effects of biguanides on key functions (cell viability, hormone release, apoptosis, and signaling pathways) in primary cell cultures from human PitNETs and cell lines. Additionally, we evaluated the effect of combined metformin with SSAs on cell viability and hormone secretion.

DESIGN

A total of 13 corticotropinomas, 13 somatotropinomas, 13 nonfunctioning PitNETs, 3 prolactinomas, and 2 tumoral pituitary cell lines (AtT-20 and GH3) were used to evaluate the direct effects of biguanides on cell viability, hormone release, apoptosis, and signaling pathways.

RESULTS

Biguanides reduced cell viability in all PitNETs and cell lines (with phenformin being the most effective biguanide) and increased apoptosis in somatotropinomas. Moreover, buformin and phenformin, but not metformin, reduced hormone secretion in a cell type-specific manner. Combination metformin/SSA therapy did not increase SSA monotherapy effectiveness. Effects of biguanides on PitNETs could involve the modulation of AMP-activated protein kinase-dependent ([Ca2+]i, PI3K/Akt) and independent (MAPK) mechanisms.

CONCLUSION

Altogether, our data unveil clear antitumoral effects of biguanides on PitNET cells, opening avenues to explore their potential as drugs to treat these pathologies.

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.

Effectiveness and safety of pegvisomant: a systematic review and meta-analysis of observational longitudinal studies

PURPOSE

Acromegaly is a rare disease that often requires drug treatment to achieve control, with pegvisomant being one of the most widely used therapies. In the present paper, we aimed to obtain evidence regarding the effectiveness and safety of pegvisomant by reviewing real-world observational longitudinal studies.

METHODS

A systematic review was performed with a meta-analysis of event rates (95% confidence interval (CI)) using a random effects model. Sensitivity and subgroup analyses were performed (comprehensive meta-analysis 2.0). The systematic review was performed in accordance to preferred reporting items for systematic reviews and meta-analyses, meta-analysis of observational studies in epidemiology, and Cochrane recommendations (PROSPERO register CRD 42017059880). PubMed, Scopus, Web of Science, and SciELO were used to search for literature. Observational studies in patients using pegvisomant for the treatment of acromegaly were included.

RESULTS

Initially, 552 papers were retrieved from the databases; and 31 articles were included in the qualitative analysis and 14 in the quantitative analysis. Eight primary meta-analyses were performed. The overall rate of patients with disease control was of 60.9% (51.8-69.3%; 95% CI). When considering patients under monotherapy, the control rate was 71.7% (64.0-78.4%; 95% CI). Tumor growth was estimated in 7.3% (4.7-11.1%; 95% CI) and elevation of transaminases in 3.0% (1.7-5.2%; 95% CI).

CONCLUSIONS

The real-world data showed that the effectiveness of pegvisomant is not as high as reported in interventional studies. Acromegaly appears to be better controlled when pegvisomant is used as a monotherapy. No serious adverse events were associated with the use of pegvisomant; however, given the high cost of this drug, further studies are required.

Updates in Diagnosis and Treatment of Acromegaly

Acromegaly is a rare disease, caused largely by a growth hormone (GH) pituitary adenoma. Incidence is higher than previously thought. Due to increased morbidity and mortality, if not appropriately treated, early diagnosis efforts are essential. Screening is recommended for all patients with clinical features of GH excess. There is increased knowledge that classical diagnostic criteria no longer apply to all, and some patients can have GH excess with normal GH response to glucose. Treatment is multifactorial and personalised therapy is advised.

How are growth hormone and insulin-like growth factor-1 reported as markers for drug effectiveness in clinical acromegaly research? A comprehensive methodologic review

OBJECTIVE

In rare disease research, most randomized prospective clinical trials can only use limited number of patients and are comprised of highly heterogeneous populations. Therefore, it is crucial to report the results in such a manner that it allows for comparison of treatment effectiveness and biochemical control between studies. The aim of this review was to investigate the current methods that are being applied to measure and report growth hormone (GH) and insulin-like growth factor-1 (IGF-1) as markers for drug effectiveness in clinical acromegaly research.

SEARCH STRATEGY

A systematic search of recent prospective and retrospective studies, published between 2012 and 2017, that studied the effects of somatostatin analogues or dopamine agonists in acromegaly patients was performed. The markers of interest were GH, IGF-1, and the suppression of GH after an oral glucose tolerance test (OGTT). Additionally, the use of pharmacokinetic (PK) measurements in these studies was analyzed. The sampling design, cut-off for biochemical control, reported units, and used summary statistics were summarized.

RESULTS

A total of 49 articles were selected out of the 263 screened abstracts. IGF-1 concentrations were measured in all 49 studies, GH in 45 studies, and an OGTT was performed in 11 studies. A wide range of different cut-off values and sampling designs were used to determine biochemical control in acromegaly patients. The summary statistics were reported in various ways, with the percentage of biochemical control most frequently used. Nine studies sampled the PK at one or more time points. Non-compartmental analyses were commonly performed on the available PK data.

CONCLUSIONS

The way GH and IGF-1 are measured and reported in acromegaly research varies considerably. A consensus on how to report study results would enable better comparisons between studies, thereby improving evidence based decision making to optimize treatment in acromegaly.

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.

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.