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

Insights from an Italian Delphi panel: exploring resistance to first-generation somatostatin receptor ligands and guiding second-line medical therapies in acromegaly management

PURPOSE

First-line medical therapy for acromegaly management includes first-generation somatostatin receptor ligands (fgSRLs), but resistance limits their use. Despite international guidelines, the choice of second-line therapy is debated.

METHODS

We aim to discuss resistance to fgSRLs, identify second-line therapy determinants and assess glycemia's impact to provide valuable insights for acromegaly management in clinical practice. A group of Italian endocrinologists expert in the pituitary field participated in a two-round Delphi panel between July and September 2023. The Delphi questionnaire encompassed a total of 75 statements categorized into three sections: resistance to fgSRLs therapy and predictors of response; determinants for the selection of second-line therapy; the role of glycemia in the therapeutic management. The statements were rated on a 6-point Likert scale.

RESULTS

Fifty-nine (79%) statements reached a consensus. IGF-1 levels resulted central for evaluating resistance to fgSRLs, that should be defined considering also symptomatic clinical response, degree of tumor shrinkage and complications, using clinician- and patient-reported outcome tools available. Factors to be evaluated for the choice of second-line medical therapy are hyperglycemia-that should be managed as in non-acromegalic patients-tumor remnant, resistant headache and compliance. Costs do not represent a main determinant in the choice of second-line medical treatment.

CONCLUSION

The experts agreed on a holistic management approach to acromegaly. It is therefore necessary to choose currently available highly effective second-line medical treatment (pegvisomant and pasireotide) based on the characteristics of the patients.

Assessment of multimodal treatment options in recurrent and persistent acromegaly: a systematic review and meta-analysis

PURPOSE

In patients with acromegaly, secondary treatment options in cases of hormonal non-remission or tumor progression include repeat transsphenoidal surgery (TSS), radiation-based treatment (RT), or medical therapy (MT). In this study, we aim to evaluate the clinical effectiveness of various second-line treatment options for acromegaly.

METHODS

Using the PRISMA guideline, a systematic review was performed by searching MEDLINE (PubMed), Web of Science, Scopus, and Cochrane electronic bibliographic databases from conception to the end of 2022. Outcomes of interest included hormonal remission rate, complications, and mortality associated with each treatment modality for refractory acromegaly.

RESULTS

A total of 79 studies including 3,208 refractory acromegaly patients (44.90% males) were analyzed, with a mean patient age of 43.89 years. There was a statistically significant difference between various therapeutic modalities in terms of remission rate, with MT offering the highest remission rate (62.55%), followed by RT (50.15%) and TSS (37.39%). Subgroup analysis of radiotherapeutic and medical modalities did not show a significant difference in remission rate between different kinds of sub-modalities in each treatment approach. Recurrence following secondary treatment was not different in patients treated with reoperation TSS compared to other modalities.

CONCLUSIONS

The management of persistent and recurrent acromegaly optimally requires a multimodal approach. In different scenarios of refractory acromegaly based on previous treatment, secondary treatments may vary in terms of remission rate and complications. Medical agents provide considerable effectiveness as a second-line therapy for recurrent or persistent disease. In selected cases, however, reoperation still provides an opportunity for cure or freedom from medications. The findings of this study may help clinicians to prioritize varying options involved in this multifaceted decision-making process.

The Multibiomarker Acro-TIME Score Predicts fg-SRLs Response: Preliminary Results of a Retrospective Acromegaly Cohort

CONTEXT

The prompt control of acromegaly is a primary treatment aim for reducing related disease morbidity and mortality. First-generation somatostatin receptor ligands (fg-SRLs) are the cornerstone of medical therapies. A non-negligible number of patients do not respond to this treatment. Several predictors of fg-SRL response were identified, but a comprehensive prognostic model is lacking.

OBJECTIVE

We aimed to design a prognostic model based on clinical and biochemical parameters, and pathological features, including data on immune tumor microenvironment.

METHODS

A retrospective, monocenter, cohort study was performed on 67 medically naïve patients with acromegaly. Fifteen clinical, pathological, and radiological features were collected and analyzed as independent risk factors of fg-SRLs response, using univariable and multivariable logistic regression analyses. A stepwise selection method was applied to identify the final regression model. A nomogram was then obtained.

RESULTS

Thirty-seven patients were fg-SRLs responders. An increased risk to poor response to fg-SRLs were observed in somatotropinomas with absent/cytoplasmatic SSTR2 expression (OR 5.493 95% CI 1.19-25.16, P = .028), with low CD68+/CD8+ ratio (OR 1.162, 95% CI 1.01-1.33, P = .032). Radical surgical resection was associated with a low risk of poor fg-SRLs response (OR 0.106, 95% CI 0.025-0.447 P = .002). The nomogram obtained from the stepwise regression model was based on the CD68+/CD8+ ratio, SSTR2 score, and the persistence of postsurgery residual tumor and was able to predict the response to fg-SRLs with good accuracy (area under the curve 0.85).

CONCLUSION

Although our predictive model should be validated in prospective studies, our data suggest that this nomogram may represent an easy to use tool for predicting the fg-SRL outcome early.

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.

Modern approach to resistant acromegaly

BACKGROUND

Targets of acromegaly treatment are normalization of biochemical values, removal/reduction/stabilization of the pituitary mass, control of clinical activity and mortality with a multimodal/multidisciplinary approach. Despite significant technological and pharmacological progress, still several patients with acromegaly bear a resistant somatotroph adenoma and active disease may persist for many years with resultant poor clinical outcomes.

AIM

To review briefly definition and pathophysiology of resistance to acromegaly treatment and the options of medical treatment in this context, exploring the role of novel clinical and molecular biomarkers in the personalization of therapy and proposing updates to the currently available guidelines for the treatment of resistant GH-secreting adenomas.

CONCLUSIONS

In the last few years, in parallel with the increased number of medical options available for the therapy of acromegaly, relevant advances occurred in the understanding of the role of novel molecular and clinical biomarkers in predicting the responsiveness to second-line medical treatments, such as Pegvisomant and Pasireotide LAR, and helping clinicians in the personalization of the follow-up and treatment of resistant somatotroph adenomas. The integration of these findings into the existing guidelines may represent a possibly important step forward in the management of "difficult" acromegaly patients.