Medical Treatments for Acromegaly: A Systematic Review and Network Meta-Analysis

Biochemical Control in a Colombian Cohort of Patients With Acromegaly: A 12-Month Follow-Up Study (2017-2023)

BACKGROUND

Acromegaly, although rare, is associated with multiple manifestations and complications; its high morbidity and mortality makes it a challenge. Treatment involves surgery and pharmacological therapies, focusing on biochemical normalization. This study analyzes the biochemical control in Colombian patients with acromegaly, seeking to improve the understanding of the effects of treatments in the management of the disease.

METHODS

A multicenter retrospective cohort study was conducted with data from a national acromegaly registry in Colombia (2017-2023), analyzing the biochemical control for 12 months according to the treatment modalities received.

RESULTS

A total of 117 patients were analyzed, with 54 individuals from Valle del Cauca and 63 being women, representing different population groups in Colombia. The median age was 52 years, and the median disease duration was six years. Clinically, arterial hypertension and sleep apnea were observed in 53.8% (n = 63) and 45.3% (n = 53) of the cohort, respectively. Biomarker analysis revealed elevated levels of insulin-like growth factor-1 (IGF-1) and growth hormone (GH). The majority of tumors were macroadenomas, and among the 103 surgically removed tumors, all secreted GH. Of these, 58.3% (n = 60) had GH as the sole marker, while 12.6% (n = 13) co-expressed prolactin (PRL). At first, 92.3% (n = 108) of patients had no biochemical control. At six and 12 months, 34.1% (n = 40) and 21.2% (n = 25) achieved biochemical control, respectively. The reduction in tumor size was significant during follow-up, with a median size at the month of admission of 16 mm, with a reduction >20% at month 12 in 92.3% (n = 108) of patients.

CONCLUSION

In Colombian patients with acromegaly, biochemical control at 12 months is lower than that reported in the literature, suggesting that pharmacological management could be associated with greater biochemical control.

Metabolomics in acromegaly: a systematic review

The therapeutic response heterogeneity in acromegaly persists, despite the medical-surgical advances of recent years. Thus, personalized medicine implementation, which focuses on each patient, is justified. Metabolomics would decipher the molecular mechanisms underlying the therapeutic response heterogeneity. Identification of altered metabolic pathways would open new horizons in the therapeutic management of acromegaly. This research aimed to evaluate the metabolomic profile in acromegaly and metabolomics' contributions to understanding disease pathogenesis. A systematic review was carried out by querying four electronic databases and evaluating patients with acromegaly through metabolomic techniques. In all, 21 studies containing 362 patients were eligible. Choline, the ubiquitous metabolite identified in growth hormone (GH)-secreting pituitary adenomas (Pas) by in vivo magnetic resonance spectroscopy (MRS), negatively correlated with somatostatin receptors type 2 expression and positively correlated with magnetic resonance imaging T2 signal and Ki-67 index. Moreover, elevated choline and choline/creatine ratio differentiated between sparsely and densely granulated GH-secreting PAs. MRS detected low hepatic lipid content in active acromegaly, which increased after disease control. The panel of metabolites of acromegaly deciphered by mass spectrometry (MS)-based techniques mainly included amino acids (especially branched-chain amino acids and taurine), glyceric acid, and lipids. The most altered pathways in acromegaly were the metabolism of glucose (particularly the downregulation of the pentose phosphate pathway), linoleic acid, sphingolipids, glycerophospholipids, arginine/proline, and taurine/hypotaurine. Matrix-assisted laser desorption/ionization coupled with MS imaging confirmed the functional nature of GH-secreting PAs and accurately discriminated PAs from healthy pituitary tissue.

Diagnosis and Management of Pituitary Adenomas: A Review

Importance

Pituitary adenomas are neoplasms of the pituitary adenohypophyseal cell lineage and include functioning tumors, characterized by the secretion of pituitary hormones, and nonfunctioning tumors. Clinically evident pituitary adenomas occur in approximately 1 in 1100 persons.

Observations

Pituitary adenomas are classified as either macroadenomas (≥10 mm) (48% of tumors) or microadenomas (<10 mm). Macroadenomas may cause mass effect, such as visual field defects, headache, and/or hypopituitarism, which occur in about 18% to 78%, 17% to 75%, and 34% to 89% of patients, respectively. Thirty percent of pituitary adenomas are nonfunctioning adenomas, which do not produce hormones. Functioning tumors are those that produce an excess of normally produced hormones and include prolactinomas, somatotropinomas, corticotropinomas, and thyrotropinomas, which produce prolactin, growth hormone, corticotropin, and thyrotropin, respectively. Approximately 53% of pituitary adenomas are prolactinomas, which can cause hypogonadism, infertility, and/or galactorrhea. Twelve percent are somatotropinomas, which cause acromegaly in adults and gigantism in children, and 4% are corticotropinomas, which secrete corticotropin autonomously, resulting in hypercortisolemia and Cushing disease. All patients with pituitary tumors require endocrine evaluation for hormone hypersecretion. Patients with macroadenomas additionally require evaluation for hypopituitarism, and patients with tumors compressing the optic chiasm should be referred to an ophthalmologist for formal visual field testing. For those requiring treatment, first-line therapy is usually transsphenoidal pituitary surgery, except for prolactinomas, for which medical therapy, either bromocriptine or cabergoline, is usually first line.

Conclusions and Relevance

Clinically manifest pituitary adenomas affect approximately 1 in 1100 people and can be complicated by syndromes of hormone excess as well as visual field defects and hypopituitarism from mass effect in larger tumors. First-line therapy for prolactinomas consists of bromocriptine or cabergoline, and transsphenoidal pituitary surgery is first-line therapy for other pituitary adenomas requiring treatment.

Pharmacological Acromegaly Treatment: Cost-Utility and Value of Information Analysis

OBJECTIVES

To conduct a cost-utility analysis comparing drug strategies involving octreotide, lanreotide, pasireotide, and pegvisomant for the treatment of patients with acromegaly who have failed surgery, from a Brazilian public payer perspective.

METHODS

A probabilistic cohort Markov model was developed. One-year cycles were employed. The patients started at 45 years of age and were followed lifelong. Costs, efficacy, and quality of life parameters were retrieved from the literature. A discount rate (5%) was applied to both costs and efficacy. The results were reported as costs per quality-adjusted life year (QALY), and incremental cost-effectiveness ratios (ICERs) were calculated when applicable. Scenario analyses considered alternative dosages, discount rate, tax exemption, and continued use of treatment despite lack of response. Value of information (VOI) analysis was conducted to explore uncertainty and to estimate the costs to be spent in future research.

RESULTS

Only lanreotide showed an ICER reasonable for having its use considered in clinical practice (R$ 112,138/US$ 28,389 per QALY compared to no treatment). Scenario analyses corroborated the base-case result. VOI analysis showed that much uncertainty surrounds the parameters, and future clinical research should cost less than R$ 43,230,000/US$ 10,944,304 per year. VOI also showed that almost all uncertainty that precludes an optimal strategy choice involves quality of life.

CONCLUSIONS

With current information, the only strategy that can be considered cost-effective in Brazil is lanreotide treatment. No second-line treatment is recommended. Significant uncertainty of parameters impairs optimal decision-making, and this conclusion can be generalized to other countries. Future research should focus on acquiring utility data.

Palliative treatment for bowel obstruction in ovarian cancer: a meta-analysis

OBJECTIVE

To comprehensively evaluate and compare outcomes of surgical versus nonsurgical palliative interventions for bowel obstruction due to ovarian cancer.

METHODS

Studies were obtained from database search systems of Pubmed, Medline, Wiley, Springerlink, Kluwer, Web of science and Science direct. Data were analyzed by the meta-analysis method and the random-effect or fixed-effect model. The heterogeneity between the studies was evaluated by I² index and the data were analyzed using STATA version 14.1.

RESULTS

12 studies involving 2778 cases of bowel obstruction in ovarian cancer were included, including 1225 cases of surgery and 1553 cases of palliative nonsurgical treatment. Surgery group had significantly higher remission rate of bowel obstruction (OR = 0.350, 95% CI 0.067-1.819, P = 0.000),but had no manifesting difference in the recurrence rate compared no-surgery group (RR = 0.88, 95% CI 0.76-1.03, P = 0.106). In 30-day mortality rate, surgery group had higher mortality rate (RR = 0.453, 95% CI 0.161-1.272, P = 0.000). But, surgical treatment can markedly prolong survival period (HR = 0.333, 95% CI 0.275-0.390, P = 0.000) compared nonsurgical treatment.

CONCLUSIONS

Surgery can significantly relieve the symptom of intestinal obstruction, prolonging the survival period, but had no impact on the recurrence. Compared with no-surgery group, surgery group suffered higher 30-day mortality.

COMPARATIVE EFFICACY OF MEDICAL TREATMENT FOR ACROMEGALY: A SYSTEMATIC REVIEW AND NETWORK META-ANALYSIS OF INTEGRATED RANDOMIZED TRIALS AND OBSERVATIONAL STUDIES

Objective: Comprehensive evidence comparing different medications for acromegaly is scarce. The aim of this study was to perform a network meta-analysis based on evidence from both randomized trials and observational studies of medical treatments for acromegaly. Methods: Electronic databases were searched for both observational studies and randomized trials that enrolled acromegaly patients treated with medications of interest. Simulated trials were generated by a machine learning algorithm and then synthesized with Bayesian random-effects network meta-analyses. The main outcome was the rate of insulin-like growth factor 1 (IGF-1) control after medical treatment. Results: We included 90 studies (100 arms, 4,523 patients) before matching. After matching, 28 simulated trials were generated. Balance of matched arms was checked by spatial distance and correlation matrix. Cotreatment with somatostatin receptor ligands and pegvisomant was the most effective treatment compared with other treatments. In unselected patients, pegvisomant was better than octreotide long-acting release (logOR, 0.85; 95% credible interval [CrI], 0.05 to 1.65) or lanreotide (logOR, 1.09, 95% CrI, 0.05 to 2.14), and the mean absolute IGF-1 control rate ranged from 40 to 60%. In partially responsive patients, cotreatment with somatostatin receptor ligands and pegvisomant was similar to pegvisomant monotherapy, ranking as the most two effective treatments, and the mean absolute IGF-1 control rate was over 60%. Conclusion: Our analysis suggested that the combination of data from observational studies and randomized trials in network meta-analysis was feasible. The findings of this network meta-analysis provided robust evidence supporting the current guidelines in treatment strategy for acromegaly. Abbreviations: CrI = credible interval; DA = dopamine agonist; GH = growth hormone; IGF-1 = insulin-like growth factor 1; ITT = intention-to-treat; LAN = lanreotide; LAN-ATG = lanreotide autogel; OCT = octreotide; OCT-LAR = octreotide long acting repeatable; OR = odds ratio; PEG = pegvisomant; PP = per-protocol; SRL = somatostatin receptor ligand.

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.

Cost-effectiveness of somatostatin analogues in the treatment of acromegaly

INTRODUCTION

Somatostatin analogues (SSAs) are the largest contributor to the direct medical cost of acromegaly management worldwide. The aim of this review was to identify and report available evidence on the cost-effectiveness of SSAs in the treatment of acromegaly.

AREAS COVERED

A literature search on relevant papers published up to April 2018 was performed. A total of 22 eligible studies (10 full-text articles and 12 conference abstracts) conducted in 14 countries were included in the analysis. In majority of studies, modelling technique was the principal research method.

EXPERT COMMENTARY

The results of cost-effectiveness analyses: 1) support published recommendations where SSAs are indicated as first-line medical treatment for patients with persistent disease after surgery or who are not eligible for surgery; 2) suggest that preoperative medical therapy with SSAs may be highly cost-effective in acromegalic patients with macroadenoma, in centres without optimal surgical results 3) indicate that in some countries pasireotide and pegvisomant appeared to be cost-effective or even dominant strategies in comparison to first-generation SSAs. The main limitation of economic evaluations was the lack of high-quality studies designed to directly compare various treatment strategies in acromegaly.