Multivariable Prediction Model for Biochemical Response to First-Generation Somatostatin Receptor Ligands in Acromegaly

Predictors of biochemical response to somatostatin receptor ligands in acromegaly

Although predictors of response to first-generation somatostatin receptor ligands (fg-SRLs), and to a lesser extent to pasireotide, have been studied in acromegaly for many years, their use is still not recommended in clinical guidelines. Is there insufficient evidence to use them? Numerous biomarkers including various clinical, functional, radiological and molecular markers have been identified. The first ones are applicable pre-surgery, while the molecular predictors are utilized for patients not cured after surgery. In this regard, factors predicting a good response to fg-SRLs are specifically: low basal GH, a low GH nadir in the acute octreotide test, T2 MRI hypointensity, a densely granulated pattern, high immunohistochemistry staining for somatostatin receptor 2 (SSTR2), and E-cadherin. However, there is still a lack of consensus regarding which of these biomarkers is more useful or how to integrate them into clinical practice. With classical statistical methods, it is complex to define reliable and generalizable cut-off values for a single biomarker. The potential solution to the limitations of traditional methods involves combining systems biology with artificial intelligence, which is currently providing answers to such long-standing questions that may eventually be finally included into the clinical guidelines and make personalized medicine a reality. The aim of this review is to describe the current knowledge of the main fg-SRLs and pasireotide response predictors, discuss their current usefulness, and point to future directions in the research of this field.

Newer parameters of the octreotide test in patients with acromegaly

PURPOSE

Predicting the therapeutic effects of first-generation somatostatin receptor ligands (fg-SRLs) is important when assessing or planning effective treatment strategies in patients with acromegaly. The oft-used maximum growth hormone (GH) suppression rate parameter of the octreotide test has a suboptimal predictive value. Therefore, this study explored newer parameters of the octreotide test for predicting the therapeutic effect of long-acting fg-SRLs.

METHODS

In this single-center retrospective study, the octreotide test parameters and the therapeutic effects of fg-SRL at 3 months were investigated in 45 consecutive treatment-naïve patients with acromegaly between April 2008 and March 2023. Additionally, the relationship between the octreotide test parameters and the therapeutic effects of fg-SRLs was investigated. Tumor shrinkage was evaluated based on changes in the longitudinal diameter of the macroadenomas. The area GH suppression rate-time under the curve (AUC) and the time to nadir GH level were calculated and compared with the maximum GH suppression rate.

RESULTS

The AUC estimated reductions in serum insulin-like growth factor I, and tumor shrinkage. The time to nadir GH level predicted tumor shrinkage more robustly than the maximum GH suppression rate in patients with macroadenoma.

CONCLUSION

The AUC and time to nadir GH level may potentially be newer parameters of the octreotide test for estimating the therapeutic effect of fg-SRLs.

Current role of pasireotide in the treatment of acromegaly

"First-generation" somatostatin receptor agonists (SSTRAs) octreotide and lanreotide are the most commonly used first-line pharmacological therapy for patients with acromegaly. A subset of patients respond only partially or not at all to the first-generation SSTRA, necessitating the use of additional pharmacological agents or other modes of therapy. Pasireotide is a "second-generation" SSTRA that has multi-receptor activity. Prospective studies have shown promise in the use of pasireotide in patients with poor response to first-generation SSTRA. Here we elucidate the molecular pathways of resistance to first-generation SSTRA, the mechanism of action, pre-clinical and clinical evidence of the use of pasireotide in patients having incomplete / lack of response to first-generation SSTRA. We also discuss the clinical, pathological, and radiological markers predicting response to pasireotide, and the difference in side-effect profiles of pasireotide, compared to first-generation SSTRA.

Radiomic Analysis in Pituitary Tumors: Current Knowledge and Future Perspectives

Radiomic analysis has emerged as a valuable tool for extracting quantitative features from medical imaging data, providing in-depth insights into various contexts and diseases. By employing methods derived from advanced computational techniques, radiomics quantifies textural information through the evaluation of the spatial distribution of signal intensities and inter-voxel relationships. In recent years, these techniques have gained considerable attention also in the field of pituitary tumors, with promising results. Indeed, the extraction of radiomic features from pituitary magnetic resonance imaging (MRI) images has been shown to provide useful information on various relevant aspects of these diseases. Some of the key topics that have been explored in the existing literature include the association of radiomic parameters with histopathological and clinical data and their correlation with tumor invasiveness and aggressive behavior. Their prognostic value has also been evaluated, assessing their role in the prediction of post-surgical recurrence, response to medical treatments, and long-term outcomes. This review provides a comprehensive overview of the current knowledge and application of radiomics in pituitary tumors. It also examines the current limitations and future directions of radiomic analysis, highlighting the major challenges that need to be addressed before a consistent integration of these techniques into routine clinical practice.

Biomarkers of response to treatment in acromegaly

INTRODUCTION

Medical treatment of acromegaly is based in a `trial and error` approach. First-generation somatostatin receptor ligands (fg-SRL) are prescribed as first-line medical therapy to the vast majority of patients, despite lack of disease control in approximately 60% of patients. However, other drugs used in acromegaly treatment are available (cabergoline, pasireotide and pegvisomant).

AREAS COVERED

In this article, we review and discuss the biomarkers of response to medical treatment in acromegaly.

EXPERT OPINION

Biomarkers for fg-SRL that can already be applied in clinical practice are: gender, age, pretreatment GH and IGF-I levels, cytokeratin granulation pattern, and the expression of somatostatin receptor type 2. Using biomarkers of response could guide treatment towards precision medicine with greater efficacy and lower costs.

Predictors of Response to Treatment with First-Generation Somatostatin Receptor Ligands in Patients with Acromegaly

BACKGROUND AND AIMS

Predictors of first-generation somatostatin receptor ligands (fgSRLs) response in acromegaly have been studied for over 30 years, but they are still not recommended in clinical guidelines. Is there not enough evidence to support their use? This systematic review aims to describe the current knowledge of the main predictors of fgSRLs response and discuss their current usefulness, as well as future research directions.

METHODS

A systematic search was performed in the Scopus and PubMed databases for functional, imaging, and molecular predictive factors.

RESULTS

A total of 282 articles were detected, of which 64 were included. Most of them are retrospective studies performed between 1990 and 2023 focused on the predictive response to fgSRLs in acromegaly. The usefulness of the predictive factors is confirmed, with good response identified by the most replicated factors, specifically low GH nadir in the acute octreotide test, T2 MRI hypointensity, high Somatostatin receptor 2 (SSTR2) and E-cadherin expression, and a densely granulated pattern. Even if these biomarkers are interrelated, the association is quite heterogeneous. With classical statistical methods, it is complex to define reliable and generalizable cut-off values worth recommending in clinical guidelines. Machine-learning models involving omics are a promising approach to achieve the highest accuracy values to date.

CONCLUSIONS

This survey confirms a sufficiently robust level of evidence to apply knowledge of predictive factors for greater efficiency in the treatment decision process. The irruption of artificial intelligence in this field is providing definitive answers to such long-standing questions that may change clinical guidelines and make personalized medicine a reality.

Survivin: A Potential Marker of Resistance to Somatostatin Receptor Ligands

CONTEXT

Invasive and somatostatin receptor ligand (SRL)-resistant pituitary tumors represent a challenge in the clinical practice of endocrinologists. Efforts have been made to elucidate reliable makers for both. Survivin and eukaryotic translation initiation factor-binding protein 1 (4EBP1) are upregulated in several cancers and involved in apoptosis and cell proliferation.

OBJECTIVE

We explored the role of these markers in somatotropinomas.

METHODS

Immunostains for survivin and 4EBP1, and also for somatostatin receptor type 2 (SSTR2), Ki-67, and cytokeratin 18, were analyzed in tissue microarrays containing 52 somatotropinoma samples. Tumor invasiveness was evaluated in all samples while drug resistance was evaluated in 34 patients who received SRL treatment. All these parameters were correlated with first-generation SRL (fg-SRL) responsiveness and tumor invasiveness.

RESULTS

Low survivin expression (P = 0.04), hyperintense signal on T2 weighted image (T2WI) (P = 0.01), younger age (P = 0.01), sparsely granular adenomas (SGA) (P = 0.04), high postoperative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels (P = 0.049 and P < 0.001, respectively), and large postoperative tumor size (P = 0.02) were associated with resistance to fg-SRL. Low survivin and SSTR2 expression and high 4EBP1 expression were associated with SGA (P = 0.04, P = 0.01, and P = 0.001, respectively). Younger age (P = 0.03), large tumor pre- and postoperative (P = 0.04 and P = 0.006, respectively), low SSTR2 expression (P = 0.03), and high baseline GH and IGF-1 (P = 0.01 and P = 0.02, respectively) were associated with tumor invasiveness. However, survivin, 4EBP1, Ki-67, and granulation patterns were not associated with tumor invasion.

CONCLUSION

This study suggests that low survivin expression is predictive of resistance to fg-SRL in somatotropinomas, but not of tumor invasiveness.

Resistance to Somatostatin Analogs in Italian Acromegaly Patients: The MISS Study

Approximately 60% of acromegaly patients are not adequately controlled by first-generation somatostatin receptor ligands. This multicenter retrospective study aimed to identify the most relevant biomarkers specific for the Italian acromegaly population. Resistant patients were enrolled consecutively based on time of neurosurgery, while responders were collected in a 1:2 ratio. Clinical characteristics and T2-intensity on MRI scans at diagnosis were retrospectively re-evaluated. Histological analyses of CAM5.2 granulation patterns and SSTR2 expression were centrally performed. Sixty-three resistant patients and thirty-three responders were enrolled. A low-grade SSTR2 expression was the most relevant predictor of resistance identified (OR 4.58, p = 0.013), even considering CAM5.2 immunohistochemistry (OR 2.65, p = 0.047). T2-iso/hyperintense pattern on MRI was also associated with a 3.3-fold greater probability of poor response to medical treatment (p = 0.027), as well as a young age at diagnosis (OR 0.96, p = 0.035). In those patients treated only after neurosurgery due to persistent GH-hypersecretion (51, 53.1%) the absence of any appreciable adenomatous remnant on postoperative MRI was associated with a negligible risk of resistance (OR 0.04, p = 0.003). In the Italian acromegaly population, a low-grade SSTR2 expression seems to be the most relevant predictor of resistance to first-generation somatostatin receptor ligands, followed by a SG/intermediate cytokeratin pattern and a T2-iso/hyperintense MRI signal.

Innovative therapeutics in acromegaly

Acromegaly is a systemic disease associated with increased morbidity and mortality that can be prevented with adequate disease control. Three modalities of treatment (surgery, medical treatment, and radiotherapy) are available; however, a significant proportion of patients still maintain disease activity despite treatment. Therefore, there is a need for innovations in the treatment of acromegaly that include changes in the current trial and error approach and the development of new drugs. In this review, we summarize the recent innovations in the treatment of acromegaly and address the future perspectives in this field.

Age, GH/IGF-1 levels, tumor volume, T2 hypointensity, and tumor subtype rather than proliferation and invasion are all reliable predictors of biochemical response to somatostatin analogue therapy in patients with acromegaly: A clinicopathological study

PURPOSE

To determine whether biochemical responses to long-acting forms of first-generation somatostatin analogue (SSA) therapy in patients with acromegaly could be predicted from baseline and postoperative hormone concentrations, and tumor radiological and histopathological characteristics.

METHODS

A total of 68 patients with acromegaly for whom postoperative SSA therapy was started were categorized according to their responses to treatment (SSA-responders vs. non-responders). The patients were compared based on their demographic characteristics, hormone levels, magnetic resonance imaging (MRI), and histopathological findings. Receiver-operating-characteristic (ROC) curves were constructed using the predictive factors that were significant in the univariate analysis to determinate the optimal cut-off values.

RESULTS

The SSA-responders were significantly older (p = 0.041). Lower GH at diagnosis (p = 0.036), the postoperative 1st-week GH level (p = 0.027), baseline GH, insulin-like growth factor-1 (IGF-1) and IGF-1% upper limit of normal (ULN) (p = 0.001, p = 0.006, p = 0.023, respectively) were associated with biochemical response. T2-hypointensity and lower tumor volume were more common in the SSA-responders (p = 0.018, p = 0.03, respectively). Compared to sparsely granulated somatotroph tumors, densely granulated somatotroph tumors and other PitNETs causing GH excess including mammosomatotroph and mixed somatotroph and lactotroph tumors were more likely to respond to SSA therapy (p = 0.026, p = 0.03, respectively). The cut-off values generated by ROC curve analysis were GH at diagnosis of ≤8.8 ng/mL, GH at baseline of ≤2.69 ng/mL, IGF-1 at baseline ≤461.5 ng/mL, IGF-1% ULN at baseline ≤180.4%, and tumor volume of ≤1.11 cm³ (all p < 0.05). There were no differences between the groups in terms of tumor invasiveness, proliferative activity (mitotic count per 2 mm² and Ki-67 labeling index) and quantitative analyses of T2-weighted MRI.

CONCLUSION

This study underscores that advanced age, low baseline GH and IGF-1 at diagnosis, low tumor volume, densely granulated tumor subtype, and T2 hypointensity may help predict biochemical response to SSA therapy in cases of acromegaly. These variables should be assessed with utmost attention for all patients prior to SSA treatment. In cases of possible resistance to SSA therapy, therapeutic activity should be monitored more closely and other therapies should be administered immediately in the event of poor response.

Paltusotine, a novel oral once-daily nonpeptide SST2 receptor agonist, suppresses GH and IGF-1 in healthy volunteers

PURPOSE

Evaluate the pharmacodynamics, pharmacokinetics, and safety of paltusotine, an orally bioavailable, nonpeptide, somatostatin receptor subtype 2 (SST2) agonist being developed for the treatment of acromegaly and neuroendocrine tumors.

METHODS

A randomized, double-blind, placebo-controlled, single center, single and multiple ascending dose phase 1 study was conducted in healthy male volunteers who received (i) single-dose of oral paltusotine 1.25, 2.5, 5, 10, and 20 mg (solution); and 40 and 60 mg (capsules) or (ii) multiple-dose oral paltusotine capsules once daily 5 mg (× 7 days), 10, 20, and 30 mg (× 10 days). Main outcome measures were pharmacodynamics (changes in growth hormone-releasing hormone [GHRH] stimulated growth hormone [GH] and insulin-like growth factor 1 [IGF-1]), pharmacokinetics, safety, and tolerability.

RESULTS

Single-dose cohorts: n = 41 active, n = 14 placebo. Multiple-dose cohorts: n = 24 active, n = 12 placebo. Paltusotine was well tolerated, orally bioavailable, associated with increased plasma concentrations to doses up to 40 mg, and was eliminated with a half-life of approximately 30 h. Single-dose paltusotine 1.25 to 20 mg suppressed GHRH-stimulated GH secretion by 44% to 93% compared to 15% with placebo. Multiple-dose paltusotine 5 to 30 mg administered once daily for 10 days suppressed IGF-1 by 19% to 37% compared to an increase of 2.4% with placebo.

CONCLUSIONS

Paltusotine suppresses GH and IGF-1 in a dose-dependent fashion, with a safety profile similar to currently approved SST2 receptor ligands. Paltusotine is a promising once-daily oral nonpeptide SST2 agonist candidate for managing acromegaly and neuroendocrine tumors.

TRIAL REGISTRATION

NCT03276858, registered September 8, 2017, retrospectively registered.

The Future of Somatostatin Receptor Ligands in Acromegaly

Currently, the first-generation somatostatin receptor ligands (fg-SRLs), octreotide LAR and lanreotide autogel, are the mainstays of acromegaly treatment and achieve biochemical control in approximately 40% of patients and tumor shrinkage in over 60% of patients. Pasireotide, a second-generation SRL, shows higher efficacy with respect to both biochemical control and tumor shrinkage but has a worse safety profile. In this review, we discuss the future perspectives of currently available SRLs, focusing on the use of biomarkers of response and precision medicine, new formulations of these SRLs and new drugs, which are under development. Precision medicine, which is based on biomarkers of response to treatment, will help guide the decision-making process by allowing physicians to choose the appropriate drug for each patient and improving response rates. New formulations of available SRLs, such as oral, subcutaneous depot, and nasal octreotide, may improve patients' adherence to treatment and quality of life since there will be more options available that better suit each patient. Finally, new drugs, such as paltusotine, somatropin, ONO-5788, and ONO-ST-468, may improve treatment adherence and present higher efficacy than currently available drugs.

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.

Clinical, hormonal and pathomorphological markers of somatotroph pituitary neuroendocrine tumors predicting the treatment outcome in acromegaly

BACKGROUND

Transsphenoidal adenomectomy (TSS) of somatotroph pituitary neuroendocrine tumor (PitNET) is the first-line treatment of acromegaly. Pharmacological treatment is recommended if surgery is contraindicated or did not lead to disease remission. The choice of treatment best fitting each patient should be based on thorough investigation of patients' characteristics. The current analysis attempts to create a tool for personalized treatment planning.

AIM

This study aimed to assess whether clinical, biochemical, imaging and pathological characteristics can predict surgical remission and response to first-generation somatostatin receptor ligands (SRLs) and pasireotide-LAR in acromegaly.

PATIENTS AND METHODS

A retrospective study of 153 acromegaly patients, treated in the Department of Endocrinology in Bielanski Hospital in Warsaw, Poland was performed. Data on demographics, hormonal and imaging results, pathological evaluation, and treatment outcome was extracted from the Polish Acromegaly Registry collecting information from 11 endocrinology centers in Poland and analyzed.

RESULTS

Patients with surgical remission had lower GH and IGF-1 concentrations at diagnosis (median GH 5.5 µg/L [IQR: 3.1-16.0] vs. 19.9 µg/L [IQR: 9.8-42.4], p=<0.001 and mean IGF-1 3.1xULN ± SD=1.2 vs. 3.7xULN ± SD=1.2, p=0.007, respectively) and smaller tumors (median 12.5mm [IQR: 9-19] vs. 23mm [IQR: 18-30], p<0.001). These tumors were more often densely granulated (DG) (73.2% vs. 40.0%, p=0.001) with positive staining for alpha-subunit (α-SU) (58.3% vs. 35.5%, p=0.021) and lower Ki-67 index (p=0.002). Patients responding well to SRLs were more often male (55.6% vs 44.4%, p=0.026), presented lower GH concentration (median GH 17.2 µg/L [IQR: 6.2-29.0] vs. 23.8 µg/L [IQR: 11.2-49.5], p=0.048) and had more often DG tumors (63.0% vs. 14.3%, p<0.001). No significant differences between good and poor-response to pasireotide-LAR groups were found. In multivariate logistic regression analysis fasting GH concentration <8.63 µg/L, maximal tumor diameter <15.5mm, normoprolactinemia and DG tumor turned out to be independent predictors of surgical remission (OR=0.92, p=0.026; OR=0.87, p=0.069, OR=3.86, p=0.096 and OR=3.05, p=0.181, respectively). Fasting GH concentration <36.6 µg/L and DG tumor turned out to be independent predictors of good response to first-generation SRLs (OR=0.96, p=0.06 and OR=10.68, p=0.002, respectively).

CONCLUSIONS

Younger age at diagnosis, male sex, lower GH, IGF-1 and PRL concentrations, smaller tumor size at diagnosis as well as positive α-SU staining, lower Ki-67 index and DG tumors predicted better treatment outcome in acromegaly patients.

Factors associated with therapeutic response in acromegaly diagnosed in the elderly in Spain

CONTEXT

Some reports suggest that acromegaly in elderly patients has a more benign clinical behavior and could have a better response to first-generation long-acting somatostatin receptor ligands (SRL). However, there is no specific therapeutic protocol for this special subgroup of patients.

OBJECTIVE

This study aimed at identifying predictors of response to SRL in elderly patients.

DESIGN

Multicentric retrospective nationwide study of patients diagnosed with acromegaly at or over the age of 65 years.

RESULTS

One-hundred and eighteen patients (34 men, 84 women, mean age at diagnosis 71.7 ± 5.4 years old) were included. Basal insulin-like growth factor type 1 (IGF-1) above the upper limit of normal (ULN) and growth hormone (GH) levels (mean ± SD) were 2.7 ± 1.4 and 11.0 ± 11.9 ng/ml, respectively. The mean maximal tumor diameter was 12.3 ± 6.4 mm, and up to 68.6% were macroadenoma. Seventy-two out of 118 patients (61.0%) underwent surgery as primary treatment. One-third of patients required first-line medical treatment due to a rejection of surgical treatment or non-suitability because of high surgical risk. After first-line surgery, 45/72 (63.9%) were in disease remission, and 16/34 (46.7%) of those treated with SRL had controlled disease. Patients with basal GH at diagnosis ≤6 ng/ml had lower IGF-1 levels and had smaller tumors, and more patients in this group reached control with SRL (72.7% vs. 33.3%; p < 0.04) [OR: 21.3, IC: 95% (2.4-91.1)], while male patients had a worse response [OR: 0.09, IC 95% (0.01-0.75)]. The predictive model curve obtained for SRL response showed an AUC of 0.82 CI (0.71-0.94).

CONCLUSIONS

The most frequent phenotype in newly diagnosed acromegaly in the elderly includes small adenomas and moderately high IGF-1 levels. GH at diagnosis ≤6 ng/ml and female gender, but not age per se, were associated with a greater chance of response to SRL.

Glucose metabolism outcomes in acromegaly patients on treatment with pasireotide-LAR or pasireotide-LAR plus Pegvisomant

INTRODUCTION

Disorders of glucose metabolism are a serious acromegaly comorbidity and may be differently impacted by medical treatments of acromegaly. In this retrospective longitudinal multicenter study, we investigated the outcome of glucose metabolism and its predictors in patients treated with Pasireotide LAR (PAS-LAR) alone or in combination with Pegvisomant (PAS-LAR + Peg-V).

SUBJECTS AND METHODS

Acromegaly patients treated continously with PAS-LAR or PAS-LAR + Peg-V for at least 6 months.

RESULTS

Forty patients (25 females, 15 males) were enrolled. At last visit, 27/40 patients (67.5%) reached biochemical control of acromegaly. Overall, glucose metabolism improved in 3 (all in PAS-LAR + Peg-V; 7.5%), worsened in 26 (65%) and remained unchanged in 11 patients (27.5%). Glucose metabolism worsened in 25 patients (73.5%) treated with PAS-LAR and in a single patient (16.7%) treated with PAS-LAR + Peg-V (p < 0.001). Among patients treated with Pas-LAR alone, GH at baseline was higher in those with worsening of glucose metabolism (p = 0.04) as compared to those with stable glucose status. A significantly higher reduction of HbA1c was observed in patients treated with PAS-LAR + Peg-V, as compared with those treated with PAS-LAR alone (p = 0.005).

CONCLUSIONS

Our data confirmed that glucose metabolism in patients treated with PAS-LAR is often worsened, and may be predicted by entity of baseline GH hypersecretion and by the dose of PAS-LAR. Moreover, our data, although limited by small numbers, may suggest that the combination treatment PAS-LAR + Peg-V can improve glucose homeostasis in selected patients.

Machine Learning-based Prediction Model for Treatment of Acromegaly With First-generation Somatostatin Receptor Ligands

CONTEXT

Artificial intelligence (AI), in particular machine learning (ML), may be used to deeply analyze biomarkers of response to first-generation somatostatin receptor ligands (fg-SRLs) in the treatment of acromegaly.

OBJECTIVE

To develop a prediction model of therapeutic response of acromegaly to fg-SRL.

METHODS

Patients with acromegaly not cured by primary surgical treatment and who had adjuvant therapy with fg-SRL for at least 6 months after surgery were included. Patients were considered controlled if they presented growth hormone (GH) <1.0 ng/mL and normal age-adjusted insulin-like growth factor (IGF)-I levels. Six AI models were evaluated: logistic regression, k-nearest neighbor classifier, support vector machine, gradient-boosted classifier, random forest, and multilayer perceptron. The features included in the analysis were age at diagnosis, sex, GH, and IGF-I levels at diagnosis and at pretreatment, somatostatin receptor subtype 2 and 5 (SST2 and SST5) protein expression and cytokeratin granulation pattern (GP).

RESULTS

A total of 153 patients were analyzed. Controlled patients were older (P = .002), had lower GH at diagnosis (P = .01), had lower pretreatment GH and IGF-I (P < .001), and more frequently harbored tumors that were densely granulated (P = .014) or highly expressed SST2 (P < .001). The model that performed best was the support vector machine with the features SST2, SST5, GP, sex, age, and pretreatment GH and IGF-I levels. It had an accuracy of 86.3%, positive predictive value of 83.3% and negative predictive value of 87.5%.

CONCLUSION

We developed a ML-based prediction model with high accuracy that has the potential to improve medical management of acromegaly, optimize biochemical control, decrease long-term morbidities and mortality, and reduce health services costs.

New and emerging pharmacological treatment options for acromegaly

Introduction: Transsphenoidal surgery is the first-line treatment for acromegaly, but even in referral centers, approximately 50% of patients are not cured, and adjuvant pharmacological treatment is necessary. Widely used therapies encompass different drug classes, such as injectable somatostatin receptor ligands (SRLs), oral dopamine agonists and injectable growth hormone receptor antagonists, but approximately 40% of patients still have disease activity in real-life practice. Therefore, there is a need for new medical therapies to allow disease control in a larger proportion of patients, increase quality of life, reduce morbidity and mortality and improve treatment adherence in acromegaly.Areas covered: In this review, the authors cover new and emerging drugs under development or drugs recently approved for the treatment of acromegaly.Expert opinion: Disease control is essential to reduce morbidity and mortality in acromegaly but is still not achieved in a significant proportion of patients or takes a long time to be achieved with currently available options and treatment algorithms. Therefore, the development of new drugs as well as the establishment of biomarkers of disease control to allow precision medicine will improve treatment and outcomes in acromegaly.

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.

Clinical and Radiological Predictors of Biochemical Response to First-Line Treatment With Somatostatin Receptor Ligands in Acromegaly: A Real-Life Perspective

BACKGROUND

First-generation somatostatin receptor ligands (fg-SRLs) represent the first-line medical treatment for acromegaly, recommended in patients with persistent disease after neurosurgery, or when surgical approach is not feasible. Despite the lack of strong recommendations from guidelines and consensus statements, data from national Registries report an increasing use of medical therapy as first-line treatment in acromegaly.

OBJECTIVE

We retrospectively evaluated the potential role of a large number of clinical and radiological parameters in predicting the biochemical response to 6-month treatment with fg-SRLs, in a cohort of naïve acromegaly patients referred to a single tertiary center for pituitary diseases.

METHODS

Univariable and multivariable logistic regression and linear regression analyses were performed. Biochemical response was defined based on IGF-1 levels, represented as both categorical (tight control, control, >50% reduction) and continuous (linear % reduction) variables.

RESULTS

Fifty-one patients (33 females, median age 57 years) were included in the study. At univariable logistic regression analysis, we found that younger age (≤ 40 years; OR 0.04, p=0.045) and higher BMI (OR 0.866, p=0.034) were associated with a lower chance of achieving >50% IGF-1 reduction. On the contrary, higher IGF-1 xULN values at diagnosis (OR 2.304, p=0.007) and a T2-hypointense tumor (OR 18, p=0.017) were associated with a significantly higher likelihood of achieving >50% IGF-1 reduction after SRL therapy. Of note, dichotomized age, IGF1 xULN at diagnosis, and T2-hypointense signal of the tumor were retained as significant predictors by our multivariable logistic regression model. Furthermore, investigating the presence of predictors to the linear % IGF-1 reduction, we found a negative association with younger age (≤ 40 years; β -0.533, p<0.0001), while a positive association was observed with both IGF-1 xULN levels at diagnosis (β 0.330, p=0.018) and the presence of a T2-hypointense pituitary tumor (β 0.466, p=0.019). All these variables were still significant predictors at multivariable analysis.

CONCLUSIONS

Dichotomized age, IGF-1 levels at diagnosis, and tumor T2-weighted signal are reliable predictors of both >50% IGF-1 reduction and linear % IGF-1 reduction after 6 month fg-SRL treatment in naïve acromegaly patients. These parameters should be considered in the light of an individualized treatment for acromegaly patients.

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.

Novel therapies for acromegaly

Acromegaly is a systemic disease associated with increased morbidity and mortality. Most of these comorbidities can be prevented or delayed with adequate disease treatment. Although three modalities of treatment (surgery, medical treatment, and radiotherapy) are available and new drugs were approved in the last decades, there are still some patients that maintain disease activity despite treatment. Therefore, there is a need for novel therapies for acromegaly and for that purpose new formulations of currently used drugs and also new drugs are currently under study. In this review, we summarize the novel therapies for acromegaly.