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

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.

Position statement on the diagnosis and management of acromegaly: The French National Diagnosis and Treatment Protocol (NDTP)

Acromegaly is a rare disease with prevalence of approximately 60 cases per million, slight female predominance and peak onset in adults in the fourth decade. Clinical diagnosis is often delayed by several years due to the slowly progressive onset of symptoms. There are multiple clinical criteria that define acromegaly: dysmorphic syndrome of insidious onset, symptoms related to the pituitary tumor (headaches, visual disorders), general signs (sweating, carpal tunnel syndrome, joint pain, etc.), complications of the disease (musculoskeletal, cardiovascular, pneumological, dental, metabolic comorbidities, thyroid nodules, colonic polyps, etc.) or sometimes clinical signs of associated prolactin hypersecretion (erectile dysfunction in men or cycle disorder in women) or concomitant mass-induced hypopituitarism (fatigue and other symptoms related to pituitary hormone deficiencies). Biological confirmation is based initially on elevated IGF-I and lack of GH suppression on oral glucose tolerance test or an elevated mean GH on repeated measurements. In confirmed cases, imaging by pituitary MRI identifies the causal tumor, to best determine management. In a minority of cases, acromegaly can be linked to a genetic predisposition, especially when it occurs at a young age or in a familial context. The first-line treatment is most often surgical removal of the somatotroph pituitary tumor, either immediately or after transient medical treatment. Medical treatments are most often proposed in patients not controlled by surgical removal. Conformal or stereotactic radiotherapy may be discussed on a case-by-case basis, especially in case of drug inefficacy or poor tolerance. Acromegaly should be managed by a multidisciplinary team, preferably within an expert center such as a reference or skill center for rare pituitary diseases.

A systematic literature review to evaluate extended dosing intervals in the pharmacological management of acromegaly

PURPOSE

This systematic literature review investigated whether extended dosing intervals (EDIs) of pharmacological acromegaly treatments reduce patient burden and costs compared with standard dosing, while maintaining effectiveness.

METHODS

MEDLINE/Embase/the Cochrane Library (2001-June 2021) and key congresses (2018-2021) were searched and identified systematic literature review bibliographies reviewed. Included publications reported on efficacy/effectiveness, safety and tolerability, health-related quality of life (HRQoL), and patient-reported and economic outcomes in longitudinal/cross-sectional studies in adults with acromegaly. Interventions included EDIs of pegvisomant, cabergoline, and somatostatin receptor ligands (SRLs): lanreotide autogel/depot (LAN), octreotide long-acting release (OCT), pasireotide long-acting release (PAS), and oral octreotide; no comparator was required.

RESULTS

In total, 35 publications reported on 27 studies: 3 pegvisomant monotherapy, 11 pegvisomant combination therapy with SRLs, 9 LAN, and 4 OCT; no studies reported on cabergoline, PAS, or oral octreotide at EDIs. Maintenance of normal insulin-like growth factor I (IGF-I) was observed in ≥ 70% of patients with LAN (1 study), OCT (1 study), and pegvisomant monotherapy (1 study). Achievement of normal IGF-I was observed in ≥ 70% of patients with LAN (3 studies) and pegvisomant in combination with SRLs (4 studies). Safety profiles were similar across EDI and standard regimens. Patients preferred and were satisfied with EDIs. HRQoL was maintained and cost savings were provided with EDIs versus standard regimens.

CONCLUSIONS

Clinical efficacy/effectiveness, safety, and HRQoL outcomes in adults with acromegaly were similar and costs lower with EDIs versus standard regimens. Physicians may consider acromegaly treatment at EDIs, especially for patients with good disease control.

Resistance of neuroendocrine tumours to somatostatin analogs

INTRODUCTION

A common feature shared by most neuroendocrine tumors (NETs) is the expression on their surface of somatostatin receptors (SSTRs) that are essential for their pathophysiological regulation, diagnosis, and management. The first-generation synthetic somatostatin analogs (SSAs), octreotide and lanreotide, constitute the cornerstone of treatment for growth hormone secreting pituitary adenomas and functioning, progressive functioning, and non-functioning gastro-entero-pancreatic (GEP-NETs). SSAs exert their mechanism of action through binding to the SSTRs; however, their therapeutic response is frequently attenuated or diminished by the development of resistance. The phenomenon of resistance is complex implicating the presence of additional epigenetic and genetic mechanisms.

AREAS COVERED

We aim to analyze the molecular, genetic, and epigenetic mechanisms of resistance to SSA treatment. We also summarize recent clinical data related to the development of resistance on conventional and non-conventional modes of administration of the first-generation SSAs and the second-generation SSA pasireotide. We explore mechanisms used to counteract the resistance to SSAs using higher doses or more frequent mode of administration of SSAs and/or combination treatments.

EXPERT OPINION

There is considerable heterogeneity in the development of resistance to SSAs that is tumor-specific necessitating the delineation of the underlying pathophysiological processes to further expand their therapeutic applications.

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

OBJECTIVE

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

DESIGN

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Pegvisomant treatment in acromegaly in clinical practice: Final results of the French ACROSTUDY (312 patients)

OBJECTIVE

We report the final analysis of the French ACROSTUDY, using data revised and enriched since the 2013 interim analysis. Our objective was to validate the use of pegvisomant (PEGV) in the treatment of acromegaly and to determine efficacy and safety.

PATIENTS AND METHODS

Patients with acromegaly treated with PEGV and followed up for at least 5 years were included. Eighty-eight investigators from 62 clinical centers in France included patients from April 2007 to April 2014. PEGV dose and administration frequency were determined by the physicians, based on their clinical evaluation and local habits. No additional examinations beyond those performed in normal follow-up were required. Minimum recommended follow-up included check-ups at treatment initiation, 6 months, 12 months and then annually.

RESULTS

In total, 312 patients were enrolled. Mean age was 46.1±14.3 years at introduction of PEGV. Median PEGV treatment duration was 6.3 years and median follow-up was 5.6 years. Median dose at initiation was 10mg/day. The percentages of patients with IGF-1 ≤ ULN (upper limit of normal) were 10% (n=300) at baseline, 54% at 6 months (n=278), and 61.7% (n=253) at 2 years, then stabilizing at 64.4% (n=180) at 5 years. Mean PEGV dose was 17.4±11.7mg in patients with controlled disease versus 21.1±17.3mg in those without control at 5 years. At 5 years, 21.8% of patients (54/248) were receiving >30mg PEGV per day. In patients with at least one pituitary imaging procedure during the 5-year follow-up (n=292), the most recent image showed stable tumor volume in 212 subjects (72.6%), increased volume in 13 (4.5%), and decreased volume in 30 (10.3%). No PEGV treatments were permanently discontinued due to transaminase elevation. There were no cases of liver failure.

CONCLUSION

The French ACROSTUDY showed normalization of IGF-1 levels in 64.4% of a real-life cohort of patients, mostly with uncontrolled disease despite multiple prior therapies. Long-term follow-up showed a sustained effectiveness and good long-term safety.