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

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.

Factors associated with disease control failure in acromegaly patients treated with pegvisomant: an ACROSTUDY analysis

Purpose

The aim of this study was to examine the probability of achieving acromegaly disease control according to several patient-, disease- and treatment-related factors longitudinally.

Methods

We analyzed data from ACROSTUDY, an open-label, noninterventional, post-marketing safety surveillance study conducted in 15 countries. A total of 1546 patients with acromegaly and treated with pegvisomant, with available information on baseline IGF-1 level, were included. Factors influencing IGF-1 control were assessed up to 10 years of follow-up by mixed-effects logistic regression models, taking into account changing values of covariates at baseline and at yearly visits. Twenty-eight anthropometric, clinical and treatment-related covariates were examined through univariate and multivariate analyses. We tested whether the probability of non-control was different than 0.50 (50%) by computing effect sizes (ES) and the corresponding 95% CI.

Results

Univariate analysis showed that age <40 years, normal or overweight, baseline IGF-1 <300 µg/L or ranged between 300 and 500 µg/L, and all pegvisomant dose <20 mg/day were associated with a lower probability of acromegaly uncontrol. Consistently, in multivariate analyses, the probability of uncontrolled acromegaly was influenced by baseline IGF-1 value: patients with IGF-1 <300 µg/L had the lowest risk of un-controlled acromegaly (ES = 0.29, 95% CI: 0.23-0.36). The probability of acromegaly uncontrol was also lower for values 300-500 µg/L (ES = 0.37, 95% CI: 0.32-0.43), while it was higher for baseline IGF-1 values ≥700 µg/L (ES = 0.58, 95% CI: 0.53-0.64).

Conclusion

Baseline IGF-l levels were a good predictor factor for long-term acromegaly control. On the contrary, our data did not support a role of age, sex, BMI and pegvisomant dose as predictors of long-term control of acromegaly.

Significance statement

Among factors that could influence and predict the efficacy of pegvisomant therapy in controlling acromegaly, a central role of baseline IGF-1 values on the probability of achieving a biochemical control of acromegaly during the treatment with pegvisomant was identified, in a real-life setting.

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.

Interpreting growth hormone and IGF-I results using modern assays and reference ranges for the monitoring of treatment effectiveness in acromegaly

Standard treatment for acromegaly focuses on the achievement of target absolute levels of growth hormone (GH) and insulin-like growth factor (IGF-I). The appropriateness of these targets when measured using modern assay methods is not well defined. This paper reviews biochemical status assessed using methods available at the time and associated clinical outcomes. GH measurements were shown to provide an indication of changes in tumor size, and failure of GH suppression after glucose stimulation is associated with tumor recurrence. IGF-I levels were more closely associated with changes in symptoms and signs. Reduced GH and IGF-I concentrations were shown to be associated with increased longevity, although the degree of increase has only been analyzed for GH. Lowering of GH and IGF-I has consistently been associated with improved outcomes; however, absolute levels reported in previous studies were based on results from methods and reference ranges that are now obsolete. Applying previously described absolute thresholds as targets (e.g. "normal" IGF-I level) when using current methods is best applied to those with active acromegaly symptoms who could benefit from further lowering of biochemical markers. In asymptomatic individuals with mild IGF-I or GH elevations, targeting biochemical "normalization" would result in the need for combination pharmacotherapy in many patients without proven benefit. Measurement of both GH and IGF-I remains an essential component of diagnosis and monitoring the effectiveness of treatment in acromegaly; however, treatment goals based only on previously identified absolute thresholds are not appropriate without taking into account the assay and reference ranges being employed. Treatment goals should be individualized considering biochemical improvement from an untreated baseline, symptoms of disease, risks, burdens and costs of complex treatment regimens, comorbidities, and quality of life.

Medical treatment of acromegaly-experience from the Croatian acromegaly registry

PURPOSE

The aim of this study was to review therapeutic outcomes of the medical treatment of patients with acromegaly based on real-world data from the Croatian Acromegaly Registry.

METHODS

In this retrospective study we investigated 163 patients (101 female, 62 male, age at diagnosis 47.2 ± 13.4 years) treated between 1990 and 2020, of which 53 were treated medically (32.5%). The duration of follow-up was 115.8 ± 304.4 months. The remission rate after the pituitary surgery was achieved in 66.5% (n = 105/158; 5 patients refused surgery). Patients who did not achieve disease remission or had a relapse during follow-up (n = 2), underwent reoperation (n = 18/60, 30%) and/or radiotherapy (n = 33/60, 55%) and/or medical treatment (n = 53/60, 88.3%). One patient refused further treatment after the failure of the first pituitary surgery.

RESULTS

Out of 53 patients treated with medical therapy, monotherapy was used in 34 (64.2%) and combination therapy in 19 (35.8%) patients. Remission (IGF-I < 1.2 upper limit of normal, ULN) was achieved in 51 patients (96.2%). Out of 53 patients, 21 (39.6%) were treated with first-generation somatostatin receptor ligand (SRL-1) monotherapy, 10 (18.9%) with dopamine agonist (DA) monotherapy, one (1.9%) with pegvisomant monotherapy, 13 (24.4%) with a combination of SRL-1 and DA, three (5.7%) with a combination of SRL-1, DA and pegvisomant, two (3.8%) with a combination of second-generation somatostatin receptor ligand (SRL-2), DA and pegvisomant and in one (1.9%) temozolomide was added on top of SRL-1 and DA. Two patients currently have active disease, both on SRL-1 monotherapy, of whom one is non-adherent to the treatment. Radiotherapy was applied to 27 (50.9%) patients on medical therapy.

CONCLUSION

Our results indicate that almost all patients with active acromegaly after pituitary surgery can achieve biochemical control with medical treatment.

Second line treatment of acromegaly: Pasireotide or Pegvisomant?

Acromegaly is a chronic disease with an increased mortality in case of persistently active disease. The treatment of acromegaly is mainly based on the surgical resection of the GH secreting pituitary tumor and, in cases with persistent disease, on the medical therapy with first generation somatostatin analogues (first gen-SSAs). Data from national registries, meta-analysis and epidemiology studies showed that 24%-65% of acromegaly patients treated with first gen-SSA did not reach the control of disease, requiring second line therapies, as the second gen-SSAs and the GH receptor antagonist. According to the high efficacy of these treatments and their molecular mechanisms of action, the choice of second line therapies should be personalized. In this review, we summarize the evidence on clinical, molecular and morphological aspects that may predict the response to second line therapies, in order to integrate and translate in the clinical practice for a patient-tailored therapeutic approach.

Partial response to first generation SSA guides the choice and predict the outcome of second line therapy in acromegaly

INTRODUCTION

Treatment of acromegaly resistant to first generation somatostatin analogues (first gen-SSA) is often difficult. We aimed to investigate the role of partial response and resistance to first gen-SSA in the choice of second line treatments and their outcomes.

PATIENTS AND METHODS

A retrospective and multicenter study was conducted on 100 SSA-resistant acromegaly patients and treated with Pasireotide Lar (Pasi-Lar), Peg-V in monotherapy (m-Peg-V) or in combination with first gen-SSA (c-Peg-V).

RESULTS

Thirty-three patients (33%) were treated with m-Peg-V, 36 (36%) with c-Peg-V and 31 with Pasi-Lar (31%). According to logistic regression, m-Peg-V was chosen in older patients (p = 0.01) and with not-invasive adenomas (p = 0.009), c-Peg-V therapy in younger patients (p = 0.001), with invasive adenomas (p = 0.02), Pasi-Lar was in invasive adenomas (p = 0.01) and in patients partially responsive to first-gen SSA (p = 0.01). At the last follow-up, 68 patients (68%) reached the acromegaly control: 22 with m-Peg-V (32.4%), 23 with c-Peg-V (33.8%) and 23 with Pasi-Lar (33.8%). Patients non-responsive to c-Peg-V had higher IGF-I levels (median 3.2 x ULN, IQR: 1.6, p &lt; 0.001) and required higher Peg-V dosage (median 30 mg/daily IQR: 10, p = 0.002) as compared to responsive patients (median IGF-I x ULN: 2.1 IQR: 1.4; median Peg-V dosage 20 mg/daily IQR: 10). All patients responsive to Pasi-Lar were partially responsive to first gen-SSAs (p = 0.02).

CONCLUSION

Our data showed that c-Peg-V and Pasi-Lar are chosen for the treatment of invasive tumors. The partial response to first gen-SSA seems to be the main determinant for the choice of Pasi-Lar and positively predicts the treatment outcome.

Are there country-specific differences in the use of pegvisomant for acromegaly in clinical practice? An analysis from ACROSTUDY

OBJECTIVE

A comprehensive picture of pegvisomant use for treating acromegaly in routine clinical practice in different countries is lacking. We aimed, therefore, to document country-specific behaviors in real-life pegvisomant use, and the main safety and effectiveness outcomes in the ACROSTUDY.

DESIGN

ACROSTUDY is an open-label, non-interventional, post-marketing safety surveillance study.

METHODS

A descriptive analysis was performed using data from the six top-recruiter ACROSTUDY countries, i.e., Germany (n = 548 patients), Italy (n = 466), France (n = 312), USA (n = 207), Spain (n = 200) and the Netherlands (n = 175). These nations accounted for > 85% of the ACROSTUDY cases.

RESULTS

The mean pegvisomant dose at treatment start was lowest in the Netherlands (9.4 mg/day), whereas it ranged between 10.9 and 12.6 mg/day in the other countries. At year 5, the mean pegvisomant dose was around 15 mg/day in all countries, except France (18.1 mg/day). At starting pegvisomant, patients treated with monotherapy ranged between 15% in the Netherlands and 72% in Spain. Monotherapy remained lowest over time in the Netherlands. In all countries, the percentage of patients with normal IGF-1 increased steeply from < 20% at baseline to 43-58% at month 6 and 51-67% at year 1. After that, we observed minor changes in the rate of acromegaly control in all countries. The Netherlands peaked in disease control at year 2 (72%). The proportion of patients reporting changes in pituitary tumor size was generally low. Serious treatment-related adverse events were < 5% in all countries.

CONCLUSIONS

Our study provided a detailed summary of real-life use of pegvisomant in the six top-recruiter ACROSTUDY nations.

Clinical Management of Acromegaly: Therapeutic Frontiers and New Perspectives for Somatostatin Receptor Ligands (SRLs)

Somatostatin receptor ligands (SRLs) represent a true milestone in the medical therapy for acromegaly. The first-generation SRLs (FG-SRLs), octreotide and lanreotide, have demonstrated good efficacy in disease control and tumor shrinkage, and are still considered first-line medical therapies. The development of long-acting release (LAR) formulations has certainly improved the therapeutic tolerability of these drugs, although many patients still experience therapy-related burden. As such, new formulations have recently been developed to improve adherence and therapeutic efficacy and more solutions are on the way. In the case of FG-SRL-resistant disease, pasireotide, the only second generation SRL currently available, demonstrated superiority in disease control and tumor shrinkage compared to FG-SRLs. However, its use in clinical practice is still limited due to concern for impairment in glucose homeostasis. In this review, we discuss the news about the present and future role of SRLs in acromegaly, exploring the therapeutical frontiers of this drug class. Moreover, we provide practical guidance on the use of pasireotide, based on the data in the literature and our clinical experience.

Acromegaly: Clinical Care in Central and Eastern Europe, Israel, and Kazakhstan

Acromegaly is a rare condition typically caused by benign pituitary adenomas, resulting in excessive production of growth hormone. Clinical manifestations of acromegaly are diverse, varying from the overgrowth of body tissue to cardiovascular, metabolic, and osteoarticular disorders. Symptoms may emerge slowly, overlapping with other diseases and often involve many different healthcare specialists. In the last decade, efforts to provide an accurate and timely diagnosis of acromegaly have improved disease management and clinical experience. Despite this progress, marked differences in the diagnosis, treatment, and management of acromegaly exist from country-to-country. To address these inconsistencies in the region comprising Central and Eastern Europe, Israel, and Kazakhstan, a panel of acromegaly experts from 13 of these countries was convened. Acromegaly experts from each country provided available information on the approaches from their country, including regional treatment centers and multidisciplinary teams, treatment access, reimbursement and availability, and physician education, disease awareness, and patient advocacy. Across several areas of acromegaly management, divergent approaches were identified and discussed, including the provision of multidisciplinary care, approved and available treatments, and disease awareness programs. These were recognized as areas of potential improvement in the management of acromegaly, in addition to participation in national and regional acromegaly registries. Further experience exchange will facilitate the identification of specific strategies that can be adapted in each country, and widespread participation in acromegaly registries will enable their evaluation. It is anticipated that this approach will support the optimization of acromegaly patient care across this region.

Pegvisomant in the treatment of acromegaly

Despite improvements in surgical techniques, current radiotherapy options and development of long-acting somatostatin analogues, biochemical control of acromegaly is not achieved in some patients. The failure to achieve optimal serum growth hormone (RH) and insulin-like growth factor-1 (IGF-1) levels means increased morbidity and mortality of acromegaly patients. The RH receptor antagonist pegvisomant (PEG) is a genetically engineered RH analog that prevents of RH receptor dimerization, i.e. a process that is crucial for the action of RH at the cellular level. The effect of the treatment is suppression of IGF-1 production. In pilot studies, normalization of IGF-1 levels was achieved in up to 90 % of patients receiving PEG. However, PEG efficacy in clinical settings is slightly lower (65 to 97 %) than reported in the key studies. A rare side effect of treatment is elevations of liver transaminases. In addition, pituitary tumor growth progression has been reported in several cases. In this review article, we present long-term data on pegvisomant treatment and discuss its associated risks and benefits.

More than a decade of real-world experience of pegvisomant for acromegaly: ACROSTUDY

OBJECTIVE

To report the final long-term safety and efficacy analyses of patients with acromegaly treated with pegvisomant from the ACROSTUDY.

DESIGN

Global (15 countries), multicentre, non-interventional study (2004-2017).

METHODS

The complete ACROSTUDY cohort comprised patients with acromegaly, who were being treated with pegvisomant (PEGV) prior to the study or at enrolment. The main endpoints were long-term safety (comorbidities, adverse events (AEs), pituitary tumour volumes, liver tests) and efficacy (IGF1 changes).

RESULTS

Patients (n = 2221) were treated with PEGV for a median of 9.3 years (range, 0-20.8 years) and followed up for a median of 7.4 years (range, 0-13.9 years). Before PEGV, 96.3% had received other acromegaly treatments (surgery/radiotherapy/medications). Before PEGV treatment, 87.2% of patients reported comorbidities. During ACROSTUDY, 5567 AEs were reported in 56.5% of patients and of these 613 were considered treatment-related (in 16.5% of patients) and led to drug withdrawal in 1.3%. Pituitary imaging showed a tumour size increase in 7.1% of patients; the majority (71.1%) reported no changes. Abnormal AST or ALT liver tests occurred in 3.2% of patients. IGF1 normalization rate improved over time, increasing from 11.4% at PEGV start to 53.7% at year 1, and reaching 75.4% at year 10 with the use of ≥30 mg PEGV/day in an increasing proportion of patients.

CONCLUSION

This comprehensive review of the complete cohort in ACROSTUDY confirmed the overall favourable benefit-to-risk profile and high efficacy of PEGV as mono- and combination therapy in patients with an aggressive course/uncontrolled/active acromegaly requiring long-term medical therapy for control.

Advances in Research on the Cardiovascular Complications of Acromegaly

Cardiovascular-related complications are one of the most common complications in patients with acromegaly, and can lead to an increased risk of death. Hypertension and cardiomyopathy are the main cardiovascular complications. The characteristics of acromegalic cardiomyopathy are concentric biventricular hypertrophy and diastolic dysfunction. In addition, arrhythmia and heart valve disease are common cardiac complications in acromegaly. Although the underlying pathophysiology has not been fully elucidated, the spontaneous overproduction of GH and IGF-1, increasing age, prolonged duration of disease and the coexistence of other cardiovascular risk factors are crucial to cardiac complications in patients with acromegaly. Early diagnosis and appropriate treatment of acromegaly might be beneficial for the prevention of cardiomyopathy and premature death.

A Pituitary Society update to acromegaly management guidelines

Guidelines and consensus statements ensure that physicians managing acromegaly patients have access to current information on evidence-based treatments to optimize outcomes. Given significant novel recent advances in understanding acromegaly natural history and individualized therapies, the Pituitary Society invited acromegaly experts to critically review the current literature in the context of Endocrine Society guidelines and Acromegaly Consensus Group statements. This update focuses on how recent key advances affect treatment decision-making and outcomes, and also highlights the likely role of recently FDA-approved therapies as well as novel combination therapies within the treatment armamentarium.

Pegvisomant in combination or pegvisomant alone after failure of somatostatin analogs in acromegaly patients: an observational French ACROSTUDY cohort study

OBJECTIVE

After surgery, when somatostatin analogs (SAs) do not normalise IGF-I, pegvisomant (PEG) is indicated. Our aim was to define the medical reasons for the treatment of patients with PEG as monotherapy (M) or combined with SA, either as primary bitherapy, PB (PEG is secondarily introduced after SA) or as secondary bitherapy, SB (SAs secondarily introduced after PEG).

METHODS

We retrospectively analysed French data from ACROSTUDY.

RESULTS

167, 88 and 57 patients were treated with M, PB or SB, respectively, during a median time of 80, 42 and 70 months. The median PEG dose was respectively 15, 10 and 20 mg. Before PEG, the mean IGF-I level did not differ between M and PB but the proportion of patients with suprasellar tumour extension was higher in PB group (67.5% vs. 44.4%, P = 0.022). SB regimen was used preferentially in patients with tumour increase and IGF-I level difficult to normalise under PEG. In both secondary regimens, the decrease of the frequency of PEG's injections, compared to monotherapy was confirmed. However, the mean weekly dose of PEG between M and PB remained the same.

CONCLUSIONS

The medical rationale for continuing SAs rather than switching to PEG alone in patients who do not normalise IGF-I under SAs was a tumour concern with suprasellar extension and tumour shrinkage under SA. A potential explanation for introducing SA in association with PEG appears to be a tumour enlargement and difficulties to normalise IGF-I levels under PEG given alone. In both regimens, the prospect of lowering PEG injection frequency favoured the choice.

Multidisciplinary management of acromegaly: A consensus

The 13th Acromegaly Consensus Conference was held in November 2019 in Fort Lauderdale, Florida, and comprised acromegaly experts including endocrinologists and neurosurgeons who considered optimal approaches for multidisciplinary acromegaly management. Focused discussions reviewed techniques, results, and side effects of surgery, radiotherapy, and medical therapy, and how advances in technology and novel techniques have changed the way these modalities are used alone or in combination. Effects of treatment on patient outcomes were considered, along with strategies for optimizing and personalizing therapeutic approaches. Expert consensus recommendations emphasize how best to implement available treatment options as part of a multidisciplinary approach at Pituitary Tumor Centers of Excellence.

Cost-Effectiveness and Efficacy of a Novel Combination Regimen in Acromegaly: A Prospective, Randomized Trial

CONTEXT

Combination therapy with somatostatin receptor ligand (SRL) plus pegvisomant for patients with acromegaly is recommended after a maximizing dose on monotherapy. Lower-dose combination regimens are not well studied.

OBJECTIVE

To compare cost-effectiveness and efficacy of 3 lower-dose combination regimens in controlled and uncontrolled acromegaly.

DESIGN AND SETTING

Prospective, randomized, open-label, parallel arm study at a tertiary referral pituitary center.

PATIENTS

Adults with acromegaly regardless of response to prior SRL and biochemical control status at baseline, stratified by an SRL dose required for insulin-like growth factor (IGF)-I normalization during any 3-month period within 12 months preceding enrollment.

INTERVENTION

Combination therapy for 24 to 32 weeks on arm A, high-dose SRL (lanreotide 120 mg/octreotide long-acting release [LAR] 30 mg) plus weekly pegvisomant (40-160 mg/week); arm B, low-dose SRL (lanreotide 60 mg/octreotide LAR 10 mg) plus weekly pegvisomant; or arm C, low-dose SRL plus daily pegvisomant (15-60 mg/day).

MAIN OUTCOME MEASURE

Monthly treatment cost in each arm in participants completing ≥ 24 weeks of therapy.

RESULTS

Sixty patients were enrolled and 52 were evaluable. Fifty of 52 (96%) demonstrated IGF-I control regardless of prior SRL responsiveness (arm A, 14/15 [93.3%]; arm B, 22/23 [95.7%]; arm C, 14/14 [100%]). Arm B was least costly (mean, $9837 ± 1375 per month), arm C was most expensive (mean, $22543 ± 11158 per month), and arm A had an intermediate cost (mean, $14261 ± 1645 per month). Approximately 30% of patients required pegvisomant dose uptitration. Rates of adverse events were all < 10%.

CONCLUSIONS

Low-dose SRL plus weekly pegvisomant represents a novel dosing option for achieving cost-effective, optimal biochemical control in patients with uncontrolled acromegaly requiring combination therapy.

Combined therapy of somatostatin analogues with pegvisomant for the treatment of acromegaly: a meta-analysis of prospective studies

BACKGROUND

Acromegaly is a rare, chronic and severe disease. Drug therapy including somatostatin analogues (SAs), dopamine receptor agonists and growth hormone receptor antagonists (pegvisomant, PEG) are commonly used to treat patients who do not respond to surgery. The use of combination therapy with PEG and SAs has become more common over the last decade. We performed this study to accurately evaluate the effect of combination therapy of SAs with PEG on acromegalic patients.

METHODS

PubMed, EMBASE, The Cochrane Library, ClinicalTrials.gov, Scopus, Web of Science, Chinese Biomedical Literature Database and Trip database were searched for relevant studies. Prospective clinical trials treating acromegaly with the co-administration of SAs and PEG were included. We performed a meta-analysis by using Stata 12.1. Sensitivity analysis was conducted to explore heterogeneity.

RESULTS

Nine studies were included in this meta-analysis. The overall rate of serum insulin-like growth factor 1 (IGF-1) normalization was 66% (95% CI: 52-78%; I² = 62.59%). The combination therapy did not significantly change patients' fasting plasma glucose (ES: 0.011 mmol*L^- 1; 95% CI: - 0.374 to 0.397 mmol*L^- 1; P = 0.954) or glycosylated haemoglobin (ES: - 0.074%; 95% CI: - 0.166 to 0.315%; P = 0.544) while decreasing the fasting plasma insulin (ES: - 21.487 pmol*L^-1; 95% CI: - 35.713 to - 7.260 pmol*L^-1; P = 0.003). Elevation of liver enzyme levels was found in 14% (95% CI: 8 to 21%) of the patients. There was no significant difference for serious adverse events and treatment discontinuation due to adverse event between SAs monotherapy group and combination therapy group.

CONCLUSIONS

Combined therapy of SAs and PEG effectively normalized IGF-1 levels in most of the patients whose IGF-1 level was greater than the upper limit of normal after high dose SAs monotherapy. The therapy also decreased significantly FPI levels with a neutral effect on glucose parameters in acromegaly patients. Moreover, elevated liver enzyme levels were observed in a small number of patients, which suggests a need for liver function monitoring.

TRIAL REGISTRATION

We have our protocol registered in PROSPERO. (Registration number: CRD42019115549 ).

Precision Therapy in Acromegaly Caused by Pituitary Tumors: How Close Is It to Reality?

Acromegaly presents with an enigmatic range of symptoms and comorbidities caused by chronic and progressive growth hormone elevations, commonly due to endocrinologic hypersecretion from a pituitary gland tumor. Comprehensive national acromegaly databases have been appearing over the years, allowing for international comparisons of data, although still presenting varying prevalence and incidence rates. Lack of large-scale analysis in geographical and ethnic differences in clinical presentation and management requires further research. Assessment of current and novel predictors of responsiveness to distinct therapy can lead to multilevel categorization of patients, allowing integration into new clinical guidelines and reduction of increased morbidity and mortality associated with acromegaly. This review compares current data from epidemiological studies and assesses the present-day application of prognostic factors in medical practice, the reality of precision therapy, as well as its future prospects in acromegaly, with a special focus on its relevance to the South Korean population.

New Epidemiological, Clinical and Economic Data for Patients With Acromegaly in Bulgaria

Background: Acromegaly and its comorbidities affect the patients' quality of life, each healthcare system and the society. This study aimed to evaluate clinical characteristics and treatment patterns and the economic burden of acromegaly.

Materials and methods: All patients with acromegaly treated with expensive medicines and regularly followed up at the main expert clinical center for acromegaly in the country were included in this nationwide, retrospective, observational, population-based study. Patient characteristics, treatment patterns, healthcare resource use, and costs were assessed for 1-year period (01.01.2018–31.12.2018). Results were processed through statistical analysis using MedCalc software version 16.4.1.

Results: A total of 191 acromegaly patients were observed. Approximately 67% were female, 45.5% were between 41 and 60 years and the mean age at diagnosis was 40.73 years. Surgical treatment was preferred as a first-line therapy among almost 89% of all diagnosed patients. The level of comorbidities was very high as more than 95% suffered from at least one concomitant disease. The most frequent comorbidities were other endocrine and metabolic diseases (96.7%), followed by cardiovascular diseases (70.7%). The most common first-line pharmacotherapy was long-acting somatostatin analogs (SSA) (38%) followed by dual combination SSA + pegvisomant (21%). The total economic burden of acromegaly was estimated to be 2,674,499.90 € in 2018 as the direct costs (medication costs, hospitalization costs covered by the patients and the National Health Insurance Fund) outnumbered indirect costs (loss of productivity due to hospitalization): 2,630,568.58 € vs. 43,931.32 €. The average annual per-patient direct and indirect costs were 14,002.62 €.

Conclusions: The current study demonstrates a significant clinical and socio-economic burden of acromegaly in the country. Proper diagnosing and regular follow up of acromegaly patients in a specialized pituitary center ensure appropriate innovative pharmacotherapy with achievement of disease control.

Long-term safety and treatment outcomes of pegvisomant in Japanese patients with acromegaly: results from the post-marketing surveillance

This post-marketing surveillance is to investigate the long-term safety and effectiveness of the growth hormone receptor antagonist pegvisomant, which is used in patients with acromegaly in routine clinical practice. This surveillance included all cases treated with pegvisomant during the study period from the start of marketing (June 5, 2007) to December 2015. Data for 251 patients with acromegaly treated with pegvisomant were collected from 119 institutions nationwide in Japan. Eighty-five patients received pegvisomant monotherapy throughout their treatment, while 165 patients were treated with somatostatin analogue or dopamine agonist in combination with pegvisomant. Mean dose of pegvisomant was 10.6 ± 6.1 mg/day in the entire treatment period (except for initial loading dose). The incidence of adverse drug reactions was 35.6% (89/250). No new safety concerns related to long-term treatment were observed. The major investigation items of incidence of abnormal liver function and tumor enlargement were 16.0% (40/250), and 5.2% (13/250) respectively. Efficacy at the final evaluation point was 96.4% (217/225) based on the overall clinical judgement of attending physicians, and efficacy in each observation period was over 94%. Improvement in IGF-I levels and clinical symptoms scores were also observed by comparing the data at baseline with each observation point during treatment. IGF-I normalization rate was 68.2% at 5 years. Pegvisomant monotherapy showed similar improvement here as well. These results suggest that long-term treatment with pegvisomant is effective in clinical practice.

Pasireotide-LAR in acromegaly patients treated with a combination therapy: a real-life study

PURPOSE

Little data are available regarding the safety and efficacy of switching to Pasireotide-LAR monotherapy in acromegaly patients with partial resistance to first-generation somatostatin agonists (1gSRL) who require combination treatment with cabergoline or pegvisomant.

METHOD

In this monocentric prospective study within a tertiary university hospital, 15 consecutive acromegalic adults partially resistant to 1gSRL treated with octreotide LAR or lanreotide SR, and cabergoline (n = 4, 3.5 mg/week) or pegvisomant (n = 11, median dose 100 mg/week), were switched to Pasireotide-LAR (8 with 40 mg/month; 7 with 60 mg/month). Immunohistochemical expression level of SSTR5 and the granulation pattern of nine somatotroph adenomas were retrospectively determined to test for a correlation with the therapeutic efficacy of Pasireotide-LAR.

RESULTS

Median IGF-1 concentration at the first evaluation (median 3 months) was similar to baseline (1.0 vs 1.1 ULN). 11/15 patients had IGF-1 levels ≤1.3 ULN before and after the switch but individual changes were variable. Hyperglycemia was frequent and greater in diabetic patients. 7/15 patients stopped Pasireotide-LAR due to lack of control of IGF-1 or intolerance. 8/15 patients received Pasireotide-LAR for a median of 29 months with IGF-1 levels ≤1.3 ULN and acceptable glucose tolerance (median HbA1c 6.1%). Two patients required initiation of oral antidiabetic treatment. The intensity of SSTR5 expression and the granulation pattern of adenomas were of limited value for the prediction of Pasireotide-LAR effectiveness.

CONCLUSION

Pasireotide-LAR may represent a suitable therapeutic alternative in a subset of acromegalic patients requiring combination therapy involving a 1gSRL.

Pegvisomant in acromegaly: a multicenter real-life study in Argentina

OBJECTIVE

To describe the long term safety and efficacy of pegvisomant (PEGV), and the predictors of treatment response in patients with acromegaly in the real life setting.

SUBJECTS AND METHODS

We retrospectively reviewed the clinical, hormonal and radiological data of acromegalic patients treated with PEGV in 17 Argentine centers.

RESULTS

Seventy-five patients (age range 22-77, 51 females) with acromegaly have been treated with PEGV for up to 118 months (median 27 months). Before PEGV, 97.3% of patients had been treated with medical therapy, surgery and/or radiotherapy, two patients had no previous treatment. At that time, all patients had an IGF-1 above the upper normal limit (ULN) (mean 2.4 x ULN ± 0.98, range 1.25-7). At diagnosis of acromegaly 84% presented macroadenomas, prior to PEGV only 23,5% of patients remained with tumor remnant > 1 cm, the remaining showed normal or less than 1 cm images. Disease control (IGF-1 ≤ 1.2 x ULN) was achieved in 62.9% of patients with a mean dose of 11.8 mg/day. Thirty-four patients (45%) received PEGV monotherapy, while 41 (55%) received combined therapy with either somatostatin analogues and/or cabergoline. Adverse events related to PEGV were: local injection site reaction in 5.3%, elevated liver enzymes in 9.3%, and tumor size growth in 9.8%. Pre-PEGV IGF-I level was the only predictor of treatment response: 2.1 x ULN vs 2.8 x ULN in controlled and uncontrolled patients respectively (p < 0.001).

CONCLUSION

this long term experience indicates PEGV treatment was highly effective and safe in our series of Argentine patients with acromegaly refractory to standard therapies. Arch Endocrinol Metab. 2019;63(4):320-7.

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.

Long-term treatment with pegvisomant: observations from 2090 acromegaly patients in ACROSTUDY

Objectives ACROSTUDY is an international, non-interventional study of acromegaly patients treated with pegvisomant (PEGV), a growth hormone receptor antagonist and has been conducted since 2004 in 15 countries to study the long-term safety and efficacy of PEGV. This report comprises the second interim analysis of 2090 patients as of May 12, 2016. Methods Descriptive analyses of safety, pituitary imaging and outcomes on PEGV treatment up to 12 years were performed. Results Prior to starting PEGV, 96% of patients had reported surgery, radiation, medical therapy or any combinations of those. At start of PEGV, 89% of patients had IGFI levels above the upper limit of normal (ULN). The percentage of patients with normal IGFI levels increased from 53% at year 1 to 73% at year 10, and the average daily dose of PEGV increased from 12.8 mg (year 1) to 18.9 mg (year 10). A total of 4832 adverse events (AEs) were reported in 1137 patients (54.4%), of which 570 were considered treatment related in 337 patients (16.1%). Serious AEs were reported in 22% of patients, of which 2.3% were considered treatment related. Locally reported MRIs showed most patients (72.2%) had no change in tumor size relative to the prior scan; 16.8% had a decrease, 6.8% an increase and 4.3% both. In patients with normal liver tests at PEGV start, an ALT or AST elevation of >3× ULN at any time point during their follow-up was reported in 3%. Conclusions This second interim analysis confirms that long-term use of PEGV is an effective and safe treatment in patients with acromegaly.