Biliary adverse events in acromegaly during somatostatin receptor ligands: predictors of onset and response to ursodeoxycholic acid treatment

Abstract Purpose Somatostatin receptor ligands (SRL) are the first-line medical treatment for acromegaly. Gallbladder alterations are one of most important SRL side effect, but according to some authors growth hormone hypersecretion itself is a risk factor for gallstones. This single center, longitudinal retrospective study evaluated the incidence and the predictors of biliary adverse events (BAE) in acromegaly during SRL therapy and their response to ursodeoxycholic acid (UDCA). Methods 91 acromegaly patients with indication to SRL were enrolled. Evaluations of acromegaly activity (GH, IGF-I, IGF-I/ULN) and metabolic profile were collected before starting treatment, yearly during follow-up and at BAE onset. In patients developing BAE we searched for predictors of UDCA effectiveness. Results 61.5% of patients developed BAE (58.9% cholelithiasis; 41.1% only sludge). IGF-I and IGF-I/ULN proved to be positive predictor of BAE, which occur about 5 years after SRL starting. None of metabolic markers proved to be associated with BAE. Only five patients (5.5%) underwent cholecystectomy for symptomatic cholelithiasis. 71% of patients started UDCA treatment, achieving regression of BAE in 60% of cases (88% in patients developing only sludge and 30% in patients affected by cholelithiasis, p < 0.001). BMI and obesity were negative predictors of UDCA efficacy. In 50% of the subjects BAE resolved after 36 months of therapy with a lower rate if cholelithiasis was present. Conclusion Biliary stone disease is a frequent SRL adverse event, although it is often symptomless. Ultrasound follow-up mainly in the first 5 years of therapy, early UDCA starting and proper lifestyle represent a valid strategy in their detection and management.

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MON-323 IGF-I Variability and Its Association with Demographic and Clinical Characteristics in Patients with Acromegaly Treated with Injectable Somatostatin Receptor Ligands (SRLS); Results from an International Prospective Phase III Study

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.1907 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Cited By ~ 1

Author(s):

Susan Leanne Samson ◽

Lisa B Nachtigall ◽

Maria Fleseriu ◽

Ehud Ur ◽

William Henry Ludlam ◽

...

Keyword(s):

Somatostatin Receptor ◽

Phase Iii ◽

Receptor Ligands ◽

Percent Change ◽

Period 2 ◽

Somatostatin Receptor Ligands ◽

Igf I ◽

Phase Iii Study ◽

The Mean

Abstract Background: In clinical practice, most patients responding to injectable somatostatin receptor ligands exhibit IGF-I variability around the upper limit of normal (ULN) during long-term follow up. These fluctuations are thought to result from various factors such as assay variability, nutrition, comorbid conditions, concomitant medications and other unknown factors. The magnitude of this variability, and the factors affecting it, is not well understood in patients with acromegaly treated with injectable SRLs. Methods: IGF-I levels of patients responding to and stably treated with injectable SRLs were measured over time in the CHIASMA OPTIMAL phase III study. Two time periods were assessed - Period 1, three assessments during screening phase before randomization to octreotide capsules (N=56), and Period 2 - multiple assessments up to week 36, in patients rescued with SRL injections for at least 12 weeks (N=21). The time from the last injection to each of the 3 assessments in period 1 [Screening visits 1 and 2 (SV1 & SV2), and Baseline (BL)], was on average 6.8 ± 10.7 (SD), 15.8 ± 2.7, and 29.0 ± 1.8 days respectively. Correlation with various demographics and Baseline characteristics, including age, gender, weight, BMI and residual tumor size to IGF-I variability was assessed. Percent change for each individual patient from Minimal to Maximal IGF-I values within each period was computed and the overall population mean was calculated (lowest value was used as the denominator and all other values were expression as a positive % above this value). Results: The overall mean within-patient percent change of IGF-I levels during Period 1 was 20.48 ± 15.56 (range: 0.6-81). Mean IGF-I levels for SV1, SV2 and BL were 0.78 ± 0.18, 0.79 ± 0.18, and 0.85 ± 0.22 x ULN respectively. The overall increase in mean IGF-I levels from SV1 to BL (longest time interval) was statistically significant (p=0.0002; paired T-test). Analysis of IGF-I levels in patients during Period 2, revealed that the overall mean within-patient percent change of IGF-I levels was 15.27 ± 12.20 (range: 0-41.5). The mean duration of follow up during this period, after patients were already treated for ≥12 weeks with injectable SRL, was 1.72 (± 1.29) months. The variability observed in Period 2 was similar to that observed in the entire sample evaluated in Period 1. No significant differences were found in the mean IGF-I percent change between any demographic or baseline characteristic subgroup examined. Conclusion: IGF-I levels fluctuate in patients with acromegaly who are responsive to injectable SRLs. These fluctuations are wide and can be up to 81% higher than the lowest (most controlled) value, with an average increase of approximately 20%. Significant IGF-I increases were observed at the end of the long acting SRL injection interval. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

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Pegvisomant and not somatostatin receptor ligands (SRLs) is first-line medical therapy for acromegaly

Acta Endocrinologica ◽

10.1530/eje-19-0998 ◽

2020 ◽

Vol 182 (6) ◽

pp. D17-D29 ◽

Cited By ~ 1

Author(s):

Aart J van der Lely ◽

Emmanuelle Kuhn ◽

Ammar Muhammad ◽

Eva C Coopmans ◽

Sebastian J Neggers ◽

...

Keyword(s):

Medical Treatment ◽

Medical Therapy ◽

Remission Rate ◽

Somatostatin Receptor ◽

Line Treatment ◽

Receptor Ligands ◽

First Line ◽

Somatostatin Receptor Ligands ◽

Igf I ◽

First Line Treatment

Current guidelines recommend the use of long-acting somatostatin receptor ligands (SRLs) first when surgery fails to correct GH/IGF-I hypersecretion in patients with acromegaly. In this issue of the journal, a pro- and contra debate will outline which arguments are in favour and which are against positioning pegvisomant (PEGV), a GH receptor antagonist, as the first-line treatment modality of acromegaly. The task of the pros was to promote a paradigm shift towards repositioning PEGV as first-line treatment as PEGV is safe and more effective than the first- and second-generation of SRLs. SRLs, when prescribed together with PEGV can still reduce tumour size when necessary, while they decrease the necessary dose of PEGV by around 50% in the average patient. They conclude that PEGV must move up towards the first-line treatment. For the cons, SRLs remain the first-line medical treatment. Indeed, even if, in recent studies, the remission rate is lower than initially claimed, SRLs are still effective not only for normalizing GH/IGF-I levels in half of the patients but also for inducing tumour shrinkage, improving comorbidities and headaches and reversing excess mortality. They are more convenient for use with their monthly administration and have a remarkable safety profile as demonstrated by the very prolonged experience acquired by more than 30 years of use. Finally, the cost-effectiveness of first-generation SRLs is better than that of PEGV. For all these reasons, cons consider that SRLs remain the best first medical treatment in patients requiring medical therapy.

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MRI follow‐up of patients with acromegaly treated after surgery with first‐generation somatostatin receptor ligands

Clinical Endocrinology ◽

10.1111/cen.14539 ◽

2021 ◽

Author(s):

Naia Grandgeorge ◽

Giovanni Barchetti ◽

Solange Grunenwald ◽

Fabrice Bonneville ◽

Philippe Caron

Keyword(s):

First Generation ◽

Somatostatin Receptor ◽

Receptor Ligands ◽

Somatostatin Receptor Ligands

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

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab125 ◽

2021 ◽

Author(s):

Luiz Eduardo Wildemberg ◽

Aline Helen da Silva Camacho ◽

Renan Lyra Miranda ◽

Paula C L Elias ◽

Nina R de Castro Musolino ◽

...

Keyword(s):

Machine Learning ◽

Support Vector Machine ◽

Prediction Model ◽

Predictive Value ◽

First Generation ◽

Somatostatin Receptor ◽

Support Vector ◽

Receptor Ligands ◽

Somatostatin Receptor Ligands ◽

Igf I

Abstract 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.

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Somatostatin receptor ligands induce TSH deficiency in thyrotropin-secreting pituitary adenoma

Acta Endocrinologica ◽

10.1530/eje-20-0484 ◽

2021 ◽

Vol 184 (1) ◽

pp. 1-8

Author(s):

Frédéric Illouz ◽

Philippe Chanson ◽

Emmanuel Sonnet ◽

Thierry Brue ◽

Amandine Ferriere ◽

...

Keyword(s):

Pituitary Adenoma ◽

Somatostatin Receptor ◽

Receptor Ligands ◽

First Line ◽

First Line Therapy ◽

Line Therapy ◽

Somatostatin Receptor Ligands ◽

Central Hyperthyroidism ◽

Long Acting ◽

Tsh Deficiency

Objective Somatostatin receptor ligands (SRL) are useful to control central hyperthyroidism in patients with thyrotropin-secreting pituitary adenoma (TSH pituitary adenoma). The aim of this study was to describe the frequency of thyrotropin deficiency (TSH deficiency) in patients with TSH pituitary adenoma treated by SRL. Design Retrospective study. Methods Patients with central hyperthyroidism due to TSH pituitary adenoma treated by short or long-acting SRL were retrospectively included. TSH deficiency was defined by a low FT4 associated with non-elevated TSH concentrations during SRL therapy. We analysed the frequency of TSH deficiency and the characteristics of patients with or without TSH deficiency. Results Forty-six patients were included. SRL were used as the first-line therapy in 21 of 46 patients (46%). Central hyperthyroidism was controlled in 36 of 46 patients (78%). TSH deficiency appeared in 7 of 46 patients (15%) after a median time of 4 weeks (4–7) and for a median duration of 3 months (2.5–3). The TSH deficiency occurred after one to three injections of long-acting SRL used as first-line therapy in 6/7 cases. There were no differences in terms of clinical and hormonal features, size of adenomas or doses of SRL between patients with or without TSH deficiency. Conclusions SRL can induce TSH deficiency in patients with central hyperthyroidism due to TSH pituitary adenoma. Thyrotropic function should be assessed before the first three injections of SRL in order to track TSH deficiency and reduce the frequency of injections when control of thyrotoxicosis rather than tumour reduction is the aim of the treatment.

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A Phase 3 Large International Noninferiority Trial (MPOWERED): Assessing Maintenance of Response to Oral Octreotide Capsules in Comparison to Injectable Somatostatin Receptor Ligands

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.1056 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A517-A517

Author(s):

Maria Fleseriu ◽

Alexander V Dreval ◽

Yulia Pokramovich ◽

Irina Bondar ◽

Elena Isaeva ◽

...

Keyword(s):

Somatostatin Receptor ◽

Safety Data ◽

Biochemical Response ◽

Receptor Ligands ◽

Phase 3 ◽

Landmark Analysis ◽

End Point ◽

Noninferiority Trial ◽

Somatostatin Receptor Ligands ◽

Igf I

Abstract Background: MPOWERED, a large phase 3 trial, assessed maintenance of response to oral octreotide capsules (OOC; MYCAPSSA®) compared to injectable somatostatin receptor ligands (iSRLs) in patients with acromegaly who responded to OOC and iSRLs (octreotide or lanreotide). OOC were recently approved in the US for patients with acromegaly who responded to and tolerated iSRLs. Methods: Eligibility criteria included age 18-75 years at screening, acromegaly diagnosis, disease evidence, biochemical control (insulin-like growth factor I [IGF-I] <1.3 × upper limit of normal [ULN] and mean integrated growth hormone [GH] <2.5 ng/mL) at screening, and ≥6 months’ iSRL treatment. Effective OOC dose was determined in a 26-week Run-in phase. Eligible patients (IGF-I <1.3 × ULN and mean integrated GH <2.5 ng/mL, week 24) were randomized to a 36-week controlled treatment phase (RCT), receiving OOC or iSRLs starting at week 26. The primary end point was a noninferiority assessment of proportion of patients biochemically controlled in the RCT (IGF-I <1.3 × ULN using time-weighted average). Other end points included nonresponse imputation of the primary end point, landmark analysis using proportion of responders based on average of last 2 IGF-I values at end of RCT, and change from baseline RCT (week 26) IGF-I and GH levels. Results: Of 146 enrolled patients, 92 entered the RCT (OOC, n=55; iSRLs, n=37). Both arms were well balanced for age, sex, and acromegaly duration. OOC demonstrated noninferiority to iSRLs in maintaining biochemical response, with 91% (CI, 80%-97%) of OOC and 100% (CI, 91%-100%) of iSRL groups maintaining control during the RCT. Of those responding at end of Run-in, 96% of patients on OOC maintained response during RCT. Using nonresponse imputation, 89% of OOC and 95% of iSRL groups were biochemically controlled in RCT. Landmark analysis of those respnding at end of Run-in showed that 94% of patients in each group maintained response at RCT end. In both groups, IGF-I levels were stable in the RCT, average IGF-I at baseline and RCT end being 0.9 × ULN (OOC) and 0.8 × ULN (iSRL). Mean change in GH from RCT start to RCT end was -0.03 ng/mL (OOC) and +0.29 ng/mL (iSRL). Safety data were mostly similar between groups; the OOC group did not experience injection site reactions. Conclusion: In this noninferiority trial in patients with acromegaly, OOC demonstrated maintenance of biochemical response compared to iSRLs. Results support the efficacy of OOC as a possible iSRL alternative.

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Pasireotide in the Personalized Treatment of Acromegaly

Frontiers in Endocrinology ◽

10.3389/fendo.2021.648411 ◽

2021 ◽

Vol 12 ◽

Author(s):

Manel Puig-Domingo ◽

Ignacio Bernabéu ◽

Antonio Picó ◽

Betina Biagetti ◽

Joan Gil ◽

...

Keyword(s):

First Generation ◽

Somatostatin Receptor ◽

Receptor Ligands ◽

First Line ◽

First Line Therapy ◽

Somatostatin Receptor Ligands ◽

Therapeutic Algorithm ◽

Surgical Failure ◽

Positive Effect ◽

T2 Mri

The delay in controlling the disease in patients who do not respond to first-line treatment with first generation somatostatin receptor ligands (first-generation SRLs) can be quantified in years, as every modification in the medical therapy requires some months to be fully evaluated. Considering this, acromegaly treatment should benefit from personalized medicine therapeutic approach by using biomarkers identifying drug response. Pasireotide has been positioned mostly as a compound to be used in first-generation SRLs resistant patients and after surgical failure, but sufficient data are now available to indicate it is a first line therapy for patients with certain characteristics. Pasireotide has been proved to be useful in patients in which hyperintensity T2 MRI signal is shown and in those depicting low SST2 and high expression of SST5, low or mutated AIP condition and sparsely granulated immunohistochemical pattern. This combination of clinical and pathological characteristics is unique for certain patients and seems to cluster in the same cases, strongly suggesting an etiopathogenic link. Thus, in this paper we propose to include this clinico-pathologic phenotype in the therapeutic algorithm, which would allow us to use as first line medical treatment those compounds with the highest potential for achieving the fastest control of GH hypersecretion as well as a positive effect upon tumor shrinkage, therefore accelerating the implementation of precision medicine for acromegaly. Moreover, we suggest the development, validation and clinical use of a pasireotide acute test, able to identify patients responsive to pasireotide LAR as the acute octreotide test is able to do for SRLs.

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

Frontiers in Endocrinology ◽

10.3389/fendo.2021.677919 ◽

2021 ◽

Vol 12 ◽

Author(s):

Federica Nista ◽

Giuliana Corica ◽

Lara Castelletti ◽

Keyvan Khorrami ◽

Claudia Campana ◽

...

Keyword(s):

Logistic Regression ◽

Somatostatin Receptor ◽

Biochemical Response ◽

Line Treatment ◽

Receptor Ligands ◽

First Line ◽

Multivariable Logistic Regression ◽

Somatostatin Receptor Ligands ◽

Younger Age ◽

First Line Treatment

BackgroundFirst-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.ObjectiveWe 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.MethodsUnivariable 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.ResultsFifty-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.ConclusionsDichotomized 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.

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MON-LB55 Biochemical Control of Most Patients Reverting to Injectable Long-Acting Somatostatin Receptor Ligands Is Achieved After One Dose: Results From the Phase 3, Randomized, Double Blind, Placebo-Controlled Optimal Study

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.2123 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Author(s):

Maria Fleseriu ◽

Susan Leanne Samson ◽

Lisa B Nachtigall ◽

Artak Labadzhyan ◽

Atanaska Elenkova ◽

...

Keyword(s):

Rescue Therapy ◽

Somatostatin Receptor ◽

Clinical Signs ◽

Placebo Treatment ◽

Receptor Ligands ◽

Biochemical Control ◽

Double Blind ◽

Double Blind Placebo ◽

Somatostatin Receptor Ligands ◽

Igf I

Abstract Background: Injectable somatostatin receptor ligands (SRLs) are currently the most widely used medical therapy for acromegaly worldwide. Oral octreotide capsules (OOC) have been formulated as a potential therapy for this disorder and the safety and efficacy were evaluated in the CHIASMA OPTIMAL pivotal study (Samson et al. ENDO 2020). As reported, mean IGF-I levels of the OOC treatment group were maintained within normal range at the end of treatment in all patients. However, some patients may not respond to OOC treatment (25% of OOC group and 68% of placebo groups required rescue, P=0.003). This analysis describes the degree and rapidity with which patients achieve biochemical control (IGF-I ≤1.0 x ULN) when reverted to their prior injectable SRL treatment. Methods: Patients with confirmed acromegaly and receiving a stable dose of injectable SRL (≥3 months) were randomized to OOC (40mg/day; N=28) or placebo (N=28) for 36 weeks. Patients were dose titrated to 60 or 80mg of OOC (or placebo) through week 24 at investigator discretion based on increased IGF-I levels and/or worsening acromegaly signs/symptoms. Patients could be rescued via reversion to prior injectable SRL therapy if they met the predefined withdrawal criteria (i.e., IGF-I ≥1.3 x upper limit of normal [ULN] for 2 consecutive visits on the highest dose, and exacerbation of clinical signs/symptoms) or discontinued treatment early for any other reason. In the study, 7 patients in the OOC group and 19 in the placebo group required rescue. The change in IGF-I from Baseline was compared to the end of the Double-blind Placebo Controlled period. Results: In patients rescued up to week 32 and in whom there were at least 4 weeks of follow up, baseline IGF-I levels (mean of Screening Visit 2 and Baseline) were 0.80 and 0.87 x ULN in the OOC and placebo groups, respectively. In patients receiving rescue therapy, the end of study IGF-I levels (mean of week 34 and 36) were 0.80 and 0.89 x ULN in the OOC and placebo groups, respectively, virtually unchanged. The median time to return to normal baseline IGF-I values following loss of response was 4.0 weeks after discontinuing OOC and 4.0 weeks after discontinuing placebo treatment. Therefore, most patients who required rescue following a short trial of therapy with OOC returned to their baseline values following a single SRL injection. Conclusion: Most treatment failures in the CHIASMA OPTIMAL trial (on either OOC or placebo) rescued with injectable SRL re-established their baseline response levels after a single injectable SRL administration (at pre-study dose). Based on this data, patients may potentially be treated with OOC and for those not responding, either not biochemically controlled or who have adverse effects, they may be able to return to injectable SRLs with immediate IGF-I control after one SRL injection.

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Safety and Efficacy of Switching Injected Peptide Long-Acting Somatostatin Receptor Ligands to Once Daily Oral Paltusotine: ACROBAT Edge Phase 2 Study

Journal of the Endocrine Society ◽

10.1210/jendso/bvab048.1073 ◽

2021 ◽

Vol 5 (Supplement_1) ◽

pp. A526-A527

Author(s):

Monica R Gadelha ◽

Murray B Gordon ◽

Mirjana Doknic ◽

Emese Mezősi ◽

Miklós Tóth ◽

...

Keyword(s):

Adverse Events ◽

Treatment Period ◽

Somatostatin Receptor ◽

Study Drug ◽

Receptor Ligands ◽

Primary Analysis ◽

Once Daily ◽

Safety And Efficacy ◽

Somatostatin Receptor Ligands ◽

Long Acting

Abstract Patients with acromegaly not cured by surgery are often initially treated with injected peptide long-acting somatostatin receptor ligands (SRLs). Non-peptide small molecules can also activate the somatostatin receptor and do so with a high degree of precision for the target therapeutic receptor subtype. Paltusotine (formerly CRN00808) is a small molecule somatostatin type 2 (SST2) receptor agonist with high oral bioavailability (70%) and pharmacokinetic profile suitable for once daily dosing. In healthy volunteers, paltusotine has been shown to lower growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels. We hypothesized that patients with acromegaly could switch from injected SRLs to once daily oral paltusotine while maintaining baseline IGF-1 levels. ACROBAT Edge (NCT03789656) was a single-arm study designed to evaluate the safety and efficacy of switching from injected SRLs to paltusotine in patients with acromegaly. The primary analysis population consisted of those who had not achieved normal IGF-1 levels despite stable therapy with long-acting octreotide or lanreotide. Eligible patients received their last injection of SRL 4 weeks prior to switching to once daily oral paltusotine monotherapy for a 13-week treatment period. The starting dose of 10 mg per day was uptitrated in 10 mg increments at specified study visits to a maximal dose of 40 mg per day based on protocol specified study drug toleration and IGF-1 criteria. The primary endpoint was change in IGF-1 from baseline to the completion of the 13-week treatment period. Statistical testing was based on non-parametric Wilcoxon Sign Rank test of whether the median change is different from zero. In addition, the rise in IGF-1 during a 4-week washout period was used to provide supportive evidence of efficacy. Twenty-five patients were enrolled in the primary analysis group, three patients discontinued from the study for non-study drug related reasons, two during the treatment period and one during the washout period after completing treatment. The primary endpoint was achieved as paltusotine treatment resulted in no significant change in IGF-1 levels at week 13 compared to baseline [change in IGF-1 =-0.034 (-0.107, 0.107), median (IQR), p>0.6]. Of the 23 patients who completed the dosing period, 20 (87%) achieved IGF-1 levels at the end of treatment that were within 20% of baseline or lower. Median IGF-1 values rose significantly after paltusotine washout (p<0.0001). The most common treatment-emergent adverse events (>10%) included: headache, arthralgia, fatigue, peripheral swelling, paresthesia and hyperhidrosis. There were no discontinuations due to adverse events and no treatment related serious adverse events. These results suggest that patients with acromegaly treated with injected SRLs can switch to oral paltusotine while maintaining IGF-1 and that paltusotine appeared to be well tolerated.

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