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

Pasireotide-induced hyperglycemia in Cushing's disease and Acromegaly: A clinical perspective and algorithms proposal

Pasireotide is an effective treatment for both Cushing's disease (CD) and acromegaly due to its ability to suppress adrenocorticotropic hormone and growth hormone, and to normalize insulin-like growth factor-1 levels, resulting in tumor shrinkage. However, it may also cause hyperglycemia as a side effect in some patients. The aim of this study was to review previous recommendations regarding the management of pasireotide-induced hyperglycemia in patients with CD and acromegaly and to propose efficient monitoring and treatment algorithms based on recent evidence and current guidelines for type 2 diabetes treatment. In about 25% of patients with CD and 50% of patients with acromegaly, pasireotide-induced hyperglycemia does not require drug therapy or can be managed with diet and oral antidiabetic agents. The risk of pasireotide-induced hyperglycemia is higher in patients with diabetes or prediabetes at baseline. Moreover, pasireotide used in the treatment of CD may lead to more frequent and difficult-to-treat glycemic disorders than those observed in acromegaly. Based on the pathomechanism of hyperglycemia, we suggest using metformin as the first-line therapy, followed by glucagon-like peptide-1 and/or sodium-glucose co-transporter-2 inhibitor, and finally insulin in patients with pasireotide-induced hyperglycemia. We propose algorithms for the management of glucose metabolic disorders caused by pasireotide treatment in patients with CD and acromegaly, including those with chronic kidney disease and at high cardiovascular risk.

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.

Novel approach to bone comorbidity in resistant acromegaly

Active acromegaly may lead to irreversible complications. Among them, acromegaly osteopathy and fragility (vertebral and hip) fractures have emerged as frequent and precocious events in the natural history of the disease, being correlated with longer disease duration and higher growth hormone (GH) levels, accounting for patients' reported poor quality of life, physical performance and other life-impacting complications. Differently from primary osteoporosis, bone mineral density is not a reliable tool to predict fracture risk in this clinical setting, as patients with active disease frequently have normal or slightly reduced bone mass; whereas bone quality is particularly compromised, as determined by low trabecular bone score (TBS) in patients with active disease as compared to healthy controls or patients with cured/controlled disease. The evidence of impaired bone microstructure has been profoundly investigated with different computed tomography (CT) techniques, reporting low trabecular number and thickness as well as wide but more porous cortical bone, providing an explanation for such a high prevalence of vertebral fractures (up to 40-50% in selected cohorts). Since data on bone-active drugs are scanty, disease control remains a cornerstone to prevent fractures. Nonetheless, some potential protective effects may derive from vitamin D supplementation and pasireotide therapies, independently from disease status. Aim of this manuscript is to review the current and emerging evidence on skeletal fragility in patients with active and resistant acromegaly.

Real-world evidence of effectiveness and safety of pasireotide in the treatment of acromegaly: a systematic review and meta-analysis

Pasireotide long-acting release (PAS-LAR) is a second-generation somatostatin receptor ligand (SRL) approved for acromegaly treatment. This meta-analysis aimed to evaluate the real-world effectiveness and safety of PAS-LAR in patients with acromegaly resistant to first-generation somatostatin receptor ligands (fgSRL). A systematic literature search was conducted in PubMed and Web of Science for real-world studies on PAS-LAR in acromegaly published between 2014 and 2023. Random-effects meta-analyses were performed on biochemical control rates, tumor shrinkage, and metabolic parameters. Twelve studies comprising 409 patients were included. The pooled rate of insulin-like growth factor 1 (IGF-1) control was 57.9% [95% CI: 48.4-66.8] and the percentage of patients with tumor shrinkage was 33.3% [95%CI: 19.7-50.4]. Significant reductions were observed in growth hormone standardized mean difference (SMD) 0.6 ng/mL [95% CI: 0.3 to 1.0] and IGF-1 levels SMD 0.9 ULN [95% CI: 0.4 to 1.4]. However, as expected, a worsening in glucose metabolism was noted as an increase in fasting glucose SMD - 0.8 mg/dL [95% CI: -1.0 to -0.5, p < 0.01], glycated hemoglobin SMD - 0.5% [95% CI: -0.7 to -0.2]. and type 2 diabetes mellitus prevalence SMD - 11.5% (95% CI: -17.5 to -5.5). PAS-LAR demonstrated higher effectiveness in real-world settings, with over 60% of patients achieving IGF-1 control compared to the around 30% efficacy observed in clinical trials. These findings suggest that PAS-LAR is an effective option for acromegaly patients resistant to fgSRL, but careful monitoring of glucose levels is essential. The high heterogeneity observed across studies emphasizes the need for identifying PAS-LAR response biomarkers to set-up individualized treatment approaches for optimizing patient outcomes.

Standards of care for medical management of acromegaly in pituitary tumor centers of excellence (PTCOE)

PURPOSE

A series of consensus guidelines on medical treatment of acromegaly have been produced in the last two decades. However, little information is available on their application in clinical practice. Furthermore, international standards of acromegaly care have not been published. The aim of our study was to report current standards of care for medical therapy of acromegaly, using results collected through an audit performed to validate criteria for definition of Pituitary Tumor Centers of Excellence (PTCOE).

METHODS

Details of medical treatment approaches to acromegaly were voluntarily provided by nine renowned international centers that participated in this audit. For the period 2018-2020, we assessed overall number of acromegaly patients under medical treatment, distribution of patients on different treatment modalities, overall biochemical control rate with medical therapy, and specific control rates for different medical treatment options.

RESULTS

Median number of total patients and median number of new patients with acromegaly managed annually in the endocrinology units of the centers were 206 and 16.3, respectively. Median percentage of acromegaly patients on medical treatment was 48.9%. Among the patients on medical treatment, first-generation somatostatin receptor ligand (SRL) monotherapy was used with a median rate of 48.7%, followed by combination therapies with a median rate of 29.3%. Cabergoline monotherapy was used in 6.9% of patients. Pegvisomant monotherapy was used in 7 centers and pasireotide monotherapy in 5 centers, with median rates of 7.9% and 6.3%, respectively.

CONCLUSIONS

Current standards of care in PTCOEs include use of first-generation SRLs as the first medical option in about 50% of patients, as recommended by consensus guidelines. However, some patients are kept on this treatment despite inadequate control suggesting that cost-effectiveness, availability, patient preference, side effects, and therapeutic inertia may play a possible role also in PTCOE. Moreover, at odds with consensus guidelines, other monotherapies for acromegaly appear to have a marginal role as compared to combination therapies as extrapolated from PTCOE practice data. Presence of uncontrolled patients in each treatment category suggest that further optimization of medical therapy, as well as use of other therapeutic tools such as radiosurgery may be needed.

Growth Hormone Receptor Antagonist Markedly Improves Gemcitabine Response in a Mouse Xenograft Model of Human Pancreatic Cancer

Chemotherapy treatment against pancreatic ductal adenocarcinoma (PDAC) is thwarted by tumoral activation of multiple therapy resistance pathways. The growth hormone (GH)-GH receptor (GHR) pair is a covert driver of multimodal therapy resistance in cancer and is overexpressed in PDAC tumors, yet the therapeutic potential of targeting the same has not been explored. Here, we report that GHR expression is a negative prognostic factor in patients with PDAC. Combinations of gemcitabine with different GHR antagonists (GHRAs) markedly improve therapeutic outcomes in nude mice xenografts. Employing cultured cells, mouse xenografts, and analyses of the human PDAC transcriptome, we identified that attenuation of the multidrug transporter and epithelial-to-mesenchymal transition programs in the tumors underlie the observed augmentation of chemotherapy efficacy by GHRAs. Moreover, in human PDAC patients, GHR expression strongly correlates with a gene signature of tumor promotion and immune evasion, which corroborate with that in syngeneic tumors in wild-type vs. GH transgenic mice. Overall, we found that GH action in PDAC promoted a therapy-refractory gene signature in vivo, which can be effectively attenuated by GHR antagonism. Our results collectively present a proof of concept toward considering GHR antagonists to improve chemotherapeutic outcomes in the highly chemoresistant PDAC.

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.

Medical treatment of functional pituitary adenomas, trials and tribulations

CONTEXT

Functioning pituitary adenomas (FPAs) include most frequently prolactinomas, somatotroph or corticotroph adenomas, while thyrotroph and gonadotroph adenomas are very rare. Despite their benign histological nature (aggressive tumors are rare and malignant ones exceptional), FPAs could cause significant morbidity and increased mortality due to complications associated with hormonal excess syndromes and/or mass effect leading to compression of adjacent structures. This mini review will focus on the increasing role of medical therapy in the multimodal treatment, which also includes transsphenoidal surgery (TSS) and radiotherapy.

EVIDENCE SYNTHESIS

Most patients with prolactinomas are treated only with medications, but surgery could be considered for some patients in a specialized pituitary center, if higher chances of cure. Dopamine agonists, especially cabergoline, are efficient in reducing tumor size and normalizing prolactin. TSS is the first-line treatment for all other FPAs, but most patients require complex adjuvant treatment, including a combination of therapeutic approaches. Medical therapy is the cornerstone of treatment in all patients after unsuccessful surgery or when surgery cannot be offered and includes somatostatin receptor ligands and dopamine agonists (almost all FPAs), growth hormone receptor antagonists (acromegaly), adrenal steroidogenesis inhibitors and glucocorticoid receptor blockers (Cushing's disease). Novel medical treatments, especially for acromegaly and Cushing's disease are under research.

CONCLUSIONS

An enlarged panel of effective drugs available with increased knowledge of predictive factors for response and/or adverse effects will enhance the possibility to offer a more individualized treatment. This would not only improve disease control and prognosis, but also quality of life.

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.

Management of pasireotide-induced hyperglycemia in patients with acromegaly: An experts' consensus statement

Pasireotide is a somatostatin analogue for the treatment of acromegaly, a chronic condition caused by excess growth hormone. Despite the therapeutic benefits of pasireotide as a second-line treatment for inadequately controlled acromegaly, a major concern is its hyperglycemic side-effect. Here, we provide guidance on how to select appropriate patients with acromegaly for treatment with pasireotide. We summarize baseline characteristics of patients at high risk for pasireotide-associated hyperglycemia and recommend a monitoring strategy based on the risk profile. Self-monitoring of blood glucose levels (SMBG), measurements of fasting plasma glucose (FPG), postprandial plasma glucose (PPG) and regular HbA1c measurements are the foundation of our proposed monitoring approach. The pathophysiology of pasireotide-induced hyperglycemia involves decreased secretion of the incretin hormones GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1). Our expert recommendations address the specific pathophysiology of pasireotide-induced hyperglycemia by recommending the incretin-based therapeutics dipeptidyl peptidase-4 inhibitors (DPP-4i) and glucagon-like peptide-1 receptor agonists (GLP-1 RA) in all appropriate patients as an alternative to first-line monotherapy with metformin. Furthermore, we emphasize the importance of adequate control of acromegaly, excellent diabetes education, nutrition and lifestyle guidance and advise to consult expert diabetologists in case of uncertainty in the management of patients with hyperglycemia under pasireotide.

Acromegaly and Bone: An Update

Since our discovery in 2006 that acromegaly is associated with an increased risk of vertebral fractures, many authors have confirmed this finding in both cross-sectional and prospective studies. Due to the high epidemiological and clinical impact of this newly discovered comorbidity of acromegaly, this topic has progressively become more important and prominent over the years, and the pertinent literature has been enriched by new findings on the pathophysiology and treatment. The aim of this narrative review was to discuss these novel findings, integrating them with the seminal observations, in order to give the reader an updated view of how the field of acromegaly and bone is developing, from strong clinical observations to a mechanistic understanding and possible prevention and treatment.

De-escalation treatment with pasireotide for acromegaly: a long-term experience

INTRODUCTION

Pasireotide long-acting release (LAR) is approved for second-line treatment of acromegaly. Starting pasireotide LAR 40 mg every 4 weeks is recommended and then up-titrate to 60 mg monthly in case of IGF-I uncontrolled levels. We present three patients treated with a de-escalation approach with pasireotide LAR. CASE 1: A 61-year-old female diagnosed with resistant acromegaly was treated with pasireotide LAR 60 mg every 28 days. When IGF-I reached the lower age range, therapy was decreased to pasireotide LAR 40 mg and then to 20 mg. In 2021 and 2022, IGF-I value remained within the normal range. CASE 2: A 40-year-old female diagnosed with resistant acromegaly underwent three neurosurgeries. In 2011, she was enrolled in the PAOLA study and assigned to pasireotide LAR 60 mg. Due to IGF-I overcontrol and radiological stability, therapy was downscaled to 40 mg in 2016 and to 20 mg in 2019. The patient developed hyperglycemia, which was treated with metformin. CASE 3: A 37-year-old male diagnosed with resistant acromegaly was treated with pasireotide LAR 60 mg in 2011. In 2018, therapy was decreased to 40 mg due to IGF-I overcontrol and in 2022 to 20 mg. He developed hyperglycemia, but HbA1c values remained under 48 nmol/L for 7 years.

CONCLUSION

De-escalation treatment with pasireotide LAR may allow a greater proportion of patients to achieve control of acromegaly, particularly in selected cases of clinically aggressive acromegaly potentially responsive to pasireotide (high IGF-I values, invasion of the cavernous sinuses, partial resistance to first-line somatostatin analogues and positive expression of somatostatin receptor 5). Another benefit may be IGF-I oversuppression overtime. The major risk seems to be hyperglycemia.

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.

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.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

Acromegaly: pathogenesis, diagnosis, and management

Growth hormone-secreting pituitary adenomas that cause acromegaly arise as monoclonal expansions of differentiated somatotroph cells and are usually sporadic. They are almost invariably benign, yet they can be locally invasive and show progressive growth despite treatment. Persistent excess of both growth hormone and its target hormone insulin-like growth factor 1 (IGF-1) results in a wide array of cardiovascular, respiratory, metabolic, musculoskeletal, neurological, and neoplastic comorbidities that might not be reversible with disease control. Normalisation of IGF-1 and growth hormone are the primary therapeutic aims; additional treatment goals include tumour shrinkage, relieving symptoms, managing complications, reducing excess morbidity, and improving quality of life. A multimodal approach with surgery, medical therapy, and (more rarely) radiation therapy is required to achieve these goals. In this Review, we examine the epidemiology, pathogenesis, diagnosis, complications, and treatment of acromegaly, with an emphasis on the importance of tailoring management strategies to each patient to optimise outcomes.

Combination of pasireotide and octreotide: effects on GH and IGF-I secretion and glucose metabolism in healthy volunteers

PURPOSE

To assess the pharmacokinetics, pharmacodynamics and tolerability of different doses of octreotide and pasireotide (subcutaneous [sc] and long-acting release [LAR]) when co-administered in healthy volunteers.

METHODS

This was an exploratory, Phase I, single-centre study. Healthy adults were enrolled in a staggered approach into seven cohorts to receive octreotide and pasireotide (sc and LAR formulations), alone or in combination. Plasma drug concentrations, growth hormone (GH), insulin-like growth factor I (IGF-I), and plasma glucose were assessed at baseline, immediately after sc treatment, and 21 and 28 days after LAR treatment.

RESULTS

Of 88 enrolled subjects, 52 and 82 participated in sc and LAR dosing phases, respectively. There were no relevant pharmacokinetic interactions between octreotide and pasireotide. In combination, pasireotide sc (150 µg) and octreotide sc (100/300 µg) resulted in numerically greater reductions in insulin levels and a higher incidence of AEs than either single agent; the rapid (within 1 h) increase in plasma glucose after pasireotide was delayed with combination treatment. Octreotide sc and pasireotide sc, alone or in combination, reduced IGF-I levels and led to undetectable GH levels in most subjects. During the LAR phase, addition of a low dose of pasireotide (5 mg) to a standard dose of octreotide (20 mg) resulted in an ~2-fold reduction in median IGF-I versus octreotide 20 mg 21 days post-dose; this effect was numerically greater than seen for pasireotide 20 mg alone. Peak plasma glucose was substantially lower after LAR than sc dosing. Interestingly, glucose levels were also numerically lower in the pasireotide 5 mg plus octreotide 20 mg group than for 20 mg of octreotide or pasireotide alone. AEs were less frequent after LAR than sc dosing.

CONCLUSIONS

Combined low doses of pasireotide LAR (5 mg) and octreotide LAR (10-30 mg) provided greater suppression of IGF-I than either single agent and did not increase blood glucose or incidence of AEs versus either agent alone.

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.