Efficacy and tolerability of the long-acting somatostatin analog lanreotide in acromegaly. A 12-month multicenter study of 58 acromegalic patients. French Multicenter Study Group on Lanreotide in Acromegaly

Multicenter, Observational Study of Lanreotide Autogel for the Treatment of Patients with Acromegaly in Routine Clinical Practice in Germany, Austria and Switzerland

BACKGROUND

Evidence from controlled trials has shown that lanreotide autogel is effective in achieving biochemical and symptom control in patients with acromegaly. However, it is important to better understand the real-world patient population receiving lanreotide autogel treatment.

METHODS

In this non-interventional study the long-term treatment response to lanreotide autogel in adult patients with acromegaly from office-based centers or clinics in Germany, Austria and Switzerland was studied. Assessments included growth hormone and insulin-like growth factor-I levels, symptoms, quality of life, lanreotide plasma levels and tumor somatostatin receptor subtype expression. The primary endpoint was achievement of full biochemical control, defined as growth hormone ≤2.5 µg/L and insulin-like growth factor I normalization at month 12.

RESULTS

76 patients were enrolled from 21 sites. 7/51 (13.7%) patients of the efficacy population had full biochemical control at baseline, 15/33 (45.5%) at month 12 and 10/26 (38.5%) at month 24 of treatment. At 12 months of treatment higher rates of biochemical control were observed in the following subgroups: older patients (>53 years [median]), females, treatment-naïve patients, and patients with a time since diagnosis of longer than 1.4 years (median). No clinically relevant differences in acromegaly symptoms or quality of life scores were observed. Median fasting blood glucose and glycated hemoglobin levels remained unchanged throughout the study. No new safety signals were observed. Overall tolerability of treatment with lanreotide autogel was judged by 80.8% of the enrolled patients at month 12 as 'very good' or 'good'.

CONCLUSION

Treatment with lanreotide autogel in a real-world setting showed long-term effectiveness and good tolerability in patients with acromegaly.

Long-Acting Somatostatin Analogue Safety Monitoring Protocol for Outpatients With Neuroendocrine Tumors

Somatostatin analogues (SSAs) are widely used in the long-term treatment of neuroendocrine tumors (NETs) and have a relatively favorable safety profile. However, SSAs are associated with specific side effects that are important to monitor. Currently, there is no standardized safety monitoring protocol for health-care professionals to use as a reference when initiating patients on long-acting SSAs. With the expansion of SSA use from symptomatic control to include antiproliferative tumor treatment in patients with NETs, it is increasingly important that patients taking these medications are properly monitored. The purpose of this analysis was to develop a comprehensive, practical SSA safety monitoring protocol for patients with NETs in the outpatient setting. This strategy was based on side effect frequencies that were reported and the monitoring parameters used in influential clinical and safety trials. Based on our assessment, we consider monitoring gallbladder imaging, laboratory tests (including blood chemistry, thyroid-stimulating hormone, hemoglobin A1c, and stool studies), vital signs, and physical examinations as the most important parameters when evaluating the safety of long-term SSA therapy. Due to the frequency at which patients experienced diarrhea as a side effect in clinical trials, questions about urgency, frequency, timing, consistency, odor, and color of bowel movements should be asked as part of the follow-up visits every 6 months to help differentiate between drug-induced vs. disease-associated causes. This broad monitoring strategy for patients receiving long-term SSAs was developed specifically for patients with NETs; however, the use of this protocol could be expanded to other indications in the future.

Somatostatin Analogs and Glucose Metabolism in Acromegaly: A Meta-analysis of Prospective Interventional Studies

INTRODUCTION

Somatostatin analogs (SSAs) effectivelycontrol growth hormone secretion in first and second line treatmentof acromegaly. Their effect onglucose metabolism is still debated.

AIM

to address the following questions: 1) Do SSAs affect fasting plasma glucose (FPG), fasting plasma insulin (FPI), glycosylated hemoglobin (HbA1c), glucose load (2h-OGTT), HOMA-I, HOMA-β, triglycerides (TGD), weight (W) or body mass index (BMI)? 2) Do lanreotide (LAN) and octreotide LAR (OCT) affect metabolism differently? 3)Does their effect depend on disease control?

METHODS

We performed a meta-analysis of prospective interventional trialstreating acromegaly with SSAs. Inclusion criteria: all studies reporting glyco-metabolic outcomes before and after SSAs with a minimum 6-month follow-up.

RESULTS

The inclusion criteria were met by 47 studies treating 1297 subjects (631 F). SSA treatment effectively lowered FPI (effect size [ES] -6.67 mU/L, 95%CI: -8.38 to -4.95mU/L; p<0.001), HOMA-I (ES -1.57, CI: -2.42 to -0.72; p<0.001), HOMA-β (ES -47.45, CI: -73.15 to -21.76; p<0.001) and TGD (ES -0.37 mmol/L, CI: -0.47 to -0.27 mmol/L; p<0.001). SSAs worsened 2h-OGTT (ES 0.59 mmol/L, CI: 0.05 to 1.13 mmol/L; p=0.032), but not FPG. A mild but significant increase in HbA1c (ES 0.12%, CI: 0.00to 0.25%; p=0.044) was found in OCT treated subjects.

CONCLUSIONS

SSA treatment in acromegaly patients-while improving disease control- reduces insulin levels, increases after load glucose and, ultimately, increases HbA1c levels without affecting FPG. The findings suggest that clinicians treating acromegaly with SSAs should consider targeting post-prandial glucose.

Remarkable Shrinkage of a Growth Hormone (GH)-secreting Macroadenoma Induced by Somatostatin Analogue Administration: A Case Report and Literature Review

Acromegaly is caused by excessive growth hormone secretion, usually from pituitary adenomas. Somoatostatin analogues are widely used as primary or adjunctive therapy in the management of acromegaly. In this report, we present a case with remarkable shrinkage of a tumor after relatively short-term octreotide long-acting release (LAR) administration. During the 30-month follow-up after starting octreotide LAR, there was no recurrence of acromegaly with remarkable shrinkage of the tumor on pituitary magnetic resonance imaging. A literature review of the predictors for tumor shrinkage after the administration of somatostatin analogues in patients with acromegaly is also discussed in relation to this case.

Endoscopic transphenoidal surgery for acromegaly improves quality of life

BACKGROUND

Acromegaly has important effects on quality of life (QOL). This is the first study to measure QOL in acromegalic patients after endoscopic transsphenoidal surgery (ETSS).

METHODS

We prospectively collected the RAND-36, Center for Epidemiologic Studies Depression (CES-D), and Pituitary QOL validated questionnaires and patients' demographics, clinical presentation, endocrine laboratory results, radiological studies, development of complications and remission rates from 20 consecutive acromegalic patients who had undergone endoscopic transphenoidal surgery.

RESULTS

The eleven females and nine males had an average age of 42 years; 90 percent had macroadenomas and 70% had cavernous sinus invasion on their preoperative imaging. Ninety percent had improved symptoms post-operatively and 80% stated that treatment improved their QOL. Biochemically, 35% were cured, 35% had discordant results and 30% were not cured, while pan-hypopituitarism occurred in 4 patients. Physical health subscales and pituitary-related symptoms were similar to norms. "Social," "emotional health," and "energy levels" were significantly lower than norms. Seventy percent stated that their relationship with their physician "very much so" affected their quality of life. Pan hypopituitarism and adjuvant therapy were the most significant predictors of lower QOL subscale scores.

CONCLUSION

Transsphenoidal surgery improves QOL in acromegaly. Attempts to achieve a cure, avoidance of surgically induced pan-hypotpituitarism and adjuvant therapy, will improve quality of life. Our study demonstrates the important role of the patient-physician relationship to QOL and the need to measure QOL in addition to the traditional measures of outcome.

Resistance to somatostatin analogs in acromegaly

Somatostatin analogs (SA) are widely used in acromegaly, either as first-line or adjuvant treatment after surgery. First-line treatment with these drugs is generally used in the patients with macroadenomas or in those with clinical conditions so severe as to prevent unsafe reactions during anesthesia. Generally, the response to SA takes into account both control of GH and IGF-I excess, with consequent improvement of clinical symptoms directly related to GH and IGF-I excess, and tumor shrinkage. This latter effect is more prominent in the patients treated first-line and bearing large macroadenomas, but it is also observed in patients with microadenomas, even with little clinical implication. Predictors of response are patients' gender, age, initial GH and IGF-I levels, and tumor mass, as well as adequate expression of somatostatin receptor types 2 and 5, those with the highest affinity for octreotide and lanreotide. Only sporadic cases of somatostatin receptor gene mutation or impaired signaling pathways have been described in GH-secreting tumors so far. The response to SA also depends on treatment duration and dosage of the drug used, so that a definition of resistance based on short-term treatments using low doses of long-acting SA is limited. Current data suggest that response to these drugs is better analyzed taking together biochemical and tumoral effects because only the absence of both responses might be considered as a poor response or resistance. This latter evidence seems to occur in 25% of treated patients after 12 months of currently available long-acting SA.

Somatostatin analog lanreotide in the treatment of castration-resistant prostate cancer (CRPC)

Prostate cancer is a common disease affecting males. Despite initial sensitivity to hormone treatment, prostate cancer eventually progresses to a castration-resistant stage (CRPC), which carries an ominous prognosis. Lanreotide is a long-acting somatostatin analog with the same properties with the native peptide. It has been shown to be highly efficacious in treating various hypersecretoty disorders and tumors. Lanreotide has been administered to patients with CRPC within a novel treatment concept, with the aim of targeting not only cancer cells but also various factors secreted in the tumor cell milieu that confer protection from apoptosis. Within this concept, lanreotide has been administered as part of the "antisurvival factor therapy" in combination with dexamethasone and a gonadotropin releasing hormone (GnRH) analog. It has also been given combined with oestrogens in patients with CRPC. The so far published series have documented a clinical response in many patients treated along with significant improvement in parameters related to quality of life. In view of these promising results, large-scale, randomized, controlled trials are warranted to clearly define the exact role of lanreotide and other somatostatin analogs in the treatment of patients with CRPC.

Effect of treatment with depot somatostatin analogue octreotide on primary hyperparathyroidism (PHP) in multiple endocrine neoplasia type 1 (MEN1) patients

BACKGROUND

In patients with multiple endocrine neoplasia type 1 (MEN1), expression of somatostatin receptor (SST) in parathyroid adenomas and effectiveness of therapy with somatostatin analogues on primary hyperparathyroidism (PHP) have been scarcely investigated.

OBJECTIVE

To evaluate the effects of depot long acting octreotide (OCT-LAR) in patients with MEN1-related PHP.

PATIENTS

Eight patients with a genetically confirmed MEN1, presenting both PHP and duodeno-pancreatic neuroendocrine tumours (NET), were enrolled.

DESIGN

The initial treatment was OCT-LAR 30 mg every 4 weeks. This therapy was established to stabilize the duodeno-pancreatic NET before to perform parathyroidectomy for PHP. Before OCT-LAR therapy, a SST scintigraphy was performed in all patients. SST subtype 2A immunohistochemistry was performed on parathyroid tumour samples from three patients undergone parathyroidectomy after OCT-LAR therapy.

MEASUREMENTS

Serum concentrations of PTH, calcium and phosphorus as well as the 24-h urine calcium : creatinine ratio and the renal threshold phosphate concentration were evaluated before and after OCT-LAR.

RESULTS

After OCT-LAR therapy, hypercalcaemia and hypercalciuria normalized in 75% and 62.5% of patients, respectively, and serum phosphorus and renal threshold phosphate significantly increased. Serum PTH concentrations significantly decreased in all patients and normalized in two of them. SST subtype 2A immunostaining was found in all parathyroid adenomas investigated, while SST scintigraphy showed a positive parathyroid tumour uptake in three of eight patients (37.5%).

CONCLUSION

Six months of OCT-LAR therapy controlled hypercalcaemia and hypercalciuria in two-thirds of patients with MEN1-related PHP. Direct OCT-LAR effects mediated by binding to SST expression on parathyroid tumour cells are likely the main mechanism to explain the activity of this compound on calcium and phosphorus abnormalities in MEN1 PHP.

Therapeutic options in the management of acromegaly: focus on lanreotide Autogel

BACKGROUND

In acromegaly, expert surgery is curative in only about 60% of patients. Postoperative radiation therapy is associated with a high incidence of hypopituitarism and its effect on growth hormone (GH) production is slow, so that adjuvant medical treatment becomes of importance in the management of many patients.

OBJECTIVE

To delineate the role of lanreotide in the treatment of acromegaly.

METHODS

Search of Medline, Embase, and Web of Science databases for clinical studies of lanreotide in acromegaly.

RESULTS

Treatment with lanreotide slow release and lanreotide Autogel((R)) normalized GH and insulin-like growth factor-I (IGF-I) concentrations in about 50% of patients. The efficacy of 120 mg lanreotide Autogel((R)) on GH and IGF-I levels was comparable with that of 20 mg octreotide LAR. There were no differences in improvement of cardiac function, decrease in pancreatic beta-cell function, or occurrence of side effects, including cholelithiasis, between octreotide LAR and lanreotide Autogel(R). When postoperative treatment with somatostatin analogs does not result in normalization of serum IGF-I and GH levels after noncurative surgery, pegvisomant alone or in combination with somatostatin analogs can control these levels in a substantial number of patients.

Somatostatin analogs and gallstones: a retrospective survey on a large series of acromegalic patients

CONTEXT

Development of gallstones (GS) is reported during the use of somatostatin analogs (SA) that are at present the mainstay for the medical treatment of acromegaly.

OBJECTIVE

To review the prevalence and clinical and biochemical correlates of GS in acromegalic patients.

DESIGN AND SETTING

Retrospective survey on hospital records in acromegalic patients followed up in the last 20 yr in tertiary referral centers.

PATIENTS

Four hundred and fifty-nine patients (272 females).

MAIN OUTCOME MEASURES

According to SA use and GS occurrence, patients were divided in 4 groups: 1) treated with SA without GS (SA+GS-), 2) GS developed while on SA (SA+GS+), 3) GS without SA use (SA-GS+), 4) neither GS nor SA (SA-GS-).

RESULTS

Patients were unevenly distributed in the 4 groups: 232, 125, 38, 64, respectively, pointing to a prevalence of GS in acromegaly of 8.3% at diagnosis with an additional 35% developing GS during SA. GS occurred after 3 months-18 yr (median 3 yr) of SA treatment, were diagnosed after symptoms in 17.6%, were associated to steatosis, ultrasound biliary dilation, and biochemical cholestasis, in 25.6%, 12.8%, and 4% of patients, respectively. Ursodehoxicolic acid was administered after GS occurrence, causing their dissolution in 39% of patients after 3-48 months (median 12). Cholecystectomy was performed in 16.8%of patients in group 2. At multivariate analysis obesity, dyslipidemia, and SA treatment were independent predictors of GS onset, whereas gender and age were not.

CONCLUSIONS

GS are a frequent occurrence in acromegalic patients treated with SA, may occur at any time, but are seldom symptomatic or prompt acute surgery. Obesity and dyslipidemia appear to play a major role in the occurrence of GS in acromegalic patients on SA treatment.

Somatostatin agonists for treatment of acromegaly

The discovery of somatotropin-release inhibitory factor (SRIF) in hypothalamic extract in 1970 led to the synthesis of the first somatostatin analog octreotide, discovery of five somatostatin receptor subtypes, and development of additional somatostatin receptor ligands (SRL) as pharmacotherapy for acromegaly and other neuroendocrine tumors. Long-acting formulations of SRL (octreotide LAR Depot, lanreotide SR and lanreotide autogel) assure improved patient compliance with weekly up to monthly injections, and are commonly used as primary or adjuvant treatment of acromegaly. We review SRL currently available, emphasizing long-acting compounds and their efficacy in controlling acromegaly. Disease control is evaluated by biochemical markers, tumor shrinkage, and disease-symptom improvement balanced against drug-related side effects.

Medical therapy: options and uses

Since the initial use of medical treatment for acromegaly, several advances have been made in the understanding of the pathophysiology of growth hormone producing tumors, resulting in the development of multiple medical options and novel treatments. Currently there are three major classes of medication available for the treatment of acromegaly: somatostatin receptor ligands, growth hormone receptor antagonists, and dopamine agonists. Somatostatin receptor ligands are the treatment of choice for acromegaly due to their effectiveness in controlling growth hormone excess in approximately 60% of patients and their beneficial effects on tumor volume. Clinical trials have demonstrated efficacy of pegvisomant in up to 97% of patients, but long term data and safety have yet to be established. Dopamine agonists are inexpensive, but their use is hampered by their lack of efficacy compared to other medications. Medical therapy has an established role as adjuvant therapy after non-curative surgery, as well as primary therapy for selected patients unsuitable for surgical resection. Medical treatment to control growth hormone hypersecretion is often needed after radiation therapy until the effects are evident. Preliminary data suggest a potential role for medical treatment prior to surgical resection, surgical debulking to improve medical efficacy, and combination therapy with multiple medications from the three classes. More studies are required, however, to validate the utility of these approaches in treating acromegaly. With the available therapies, disease control can be achieved in nearly all patients with acromegaly.

Efficacy of a slow-release formulation of lanreotide (Autogel) 120 mg) in patients with acromegaly previously treated with octreotide long acting release (LAR): an open, multicentre longitudinal study

OBJECTIVE

Lanreotide Autogel 120 mg (ATG120; Ipsen S.p.A, Milan, Italy) is a high-dose, sustained-release aqueous gel formulation, supplied in a prefilled syringe and given by deep subcutaneous injection. The aim of this study was to compare efficacy and tolerability of ATG120 given every 4-8 weeks with those of octreotide LAR (o-LAR) given every 4 weeks. DESIGN PATIENTS AND INTERVENTION: A phase III multicentre Italian open clinical study of 23 acromegalic patients (15 female, 8 male). All patients had received o-LAR for 6-18 months and, after 3 months wash out, ATG120 was given every 6 weeks for a total of four injections (Period 1). Then the interval between ATG120 injections was adjusted according to three different schemes: every 4, 6 or 8 weeks depending on GH levels (GH > 2.5 microg/l; 1 < GH <or= 2.5 microg/l; GH <or= 1 microg/l, respectively). ATG120 was given for a further two to three doses, with a final assessment (Period 2) at Week 34, 36 or 42.

MEASUREMENTS

Hormonal (GH and IGF-I) and clinical efficacy and tolerability.

RESULTS

ATG120 induced a significant GH decrease from 9.9 +/- 11.3 at baseline (Visit 1) to 3.5 +/- 5.7 at the end of Period 1 (P < 0.01) and to 3.8 +/- 5.7 microg/l at the final visit (P < 0.01). IGF-I also decreased from 544 +/- 312 at baseline (Visit 1) to 318 +/- 181 at Period 1 and to 356 +/- 187 microg/l at the final visit (both P < 0.05 vs. baseline). The frequency of ATG120 administrations was adjusted to every 4 weeks in 12 patients, every 6 weeks in 4 patients and every 8 weeks in 6 patients; 1 patient withdrew before the dose adjustment. Serum GH and IGF-I achieved at the end of Period 1 and Period 2 were similar to those reached with o-LAR. The number of patients who achieved GH < 2.5 microg/l was comparable between o-LAR (43%) and ATG120 at Period 1 (48%) and at Period 2 (62%). Normal IGF-I levels were recorded in 8 patients during o-LAR (35%), 11 during ATG Period 1 (48%) and 10 at the final visit (43%). Last, 4 patients showed a better response to ATG120 and 2 to o-LAR.

CONCLUSIONS

Lanreotide Autogel 120 mg is an effective and well-tolerated therapy for acromegaly. In approximately half of patients ATG120 may be administered every 6-8 weeks, instead of every 4 weeks, without lost of efficacy.

Role of radiotherapy in the management of acromegaly

Active acromegaly can be treated effectively by transsphenoidal surgery, radiotherapy and medical treatment in the form of somatostatin analogs and growth hormone receptor antagonists. Many patients will require a combination of treatment modalities to normalize growth hormone excess and associated increased mortality, and to improve comorbidity. Following postoperative radiotherapy, growth hormone and insulin-like growth factor-I levels gradually decrease and normalization of growth hormone and insulin-like growth factor-I is achieved in 50% of patients after 5 years and 75% after 10 years. Disadvantages of radiotherapy include the long interval until hormone levels have sufficiently decreased and the high incidence of radiation-induced hypopituitarism. Radiotherapy was associated with increased mortality in some but not other studies. Limitations in the design and confounding factors, such as years spent with active disease and changing treatment strategies, make it impossible to draw conclusions on this topic. Gamma knife radiosurgery may combine faster decline of growth hormone excess with a lower incidence of hypopituitarism in eligible cases, but long-term results of this radiation technique are lacking. At present, patients will preferentially be treated by primary surgery and/or somatostatin analog treatment, followed, if necessary, by growth hormone receptor antagonist treatment, while radiotherapy is reserved for selected cases only. The indications for radiotherapy and radiosurgery need to be revisited in the near future, when longer follow-up results for medical treatment and radiosurgery have become available. This review summarizes the recent literature on efficacy and side effects of radiotherapy and radiosurgery in acromegaly and discusses the place of radiation treatment in the treatment algorithm of acromegaly.

Treatment strategies for acromegaly

Acromegaly is a chronic debilitating disorder caused by a growth hormone (GH)-producing pituitary adenoma. Active acromegaly is associated with a two- to fourfold increased mortality risk, mainly from cardiovascular disease. Transsphenoidal surgery is considered as the treatment of choice because of the rapidity of cure and normalisation of survival. Secondary treatment modalities are radiotherapy and medical treatment, and are important because surgery in the best hands cures only approximately 60% in long-term studies. Medical treatment with slow-release formulations of somatostatin are now widely used, also as primary treatment, and appear to be safe and effective in 50-60% of the patients. However, no data on mortality risk with these drugs is available. Recently, a GH-receptor blocking agent, pegvisomant, was licensed for use in acromegaly and appears to normalise IGF-1 in almost all patients. This article examines the pathophysiology of acromegaly, currently used medicines and their safety and efficacy, and the new drugs that are in development.

Partial surgical removal of growth hormone-secreting pituitary tumors enhances the response to somatostatin analogs in acromegaly

CONTEXT

Surgery is a cornerstone in the treatment of acromegaly, but its efficacy in large, invasive tumors is scant.

OBJECTIVE

The objective of this study was to investigate whether partial surgical removal of GH-secreting pituitary tumors enhances the response rate to somatostatin analogs (SSA; sc octreotide, slow-release octreotide, and lanreotide).

DESIGN

This was a multicenter, open, retrospective study.

SETTING

The study was performed at university hospitals.

SUBJECTS AND METHODS

Eighty-six patients (42 women and 44 men; age, 42 +/- 14 yr) with acromegaly were studied.

INTERVENTIONS

Patients underwent two courses of octreotide, lanreotide, or slow-release octreotide treatments before and after surgery of at least 6 months.

MAIN OUTCOME MEASURE

The main outcome measure was normal IGF-I levels for age.

RESULTS

Presurgical SSA treatment significantly decreased GH and IGF-I levels in all patients. GH levels were less than 2.5 microg/liter in 12 patients (14%); IGF-I levels normalized in nine (10%). After surgery, GH and IGF-I levels further decreased in all patients; tumor removal was greater than 75% in 50 (58%), 50.1-75% in 21 (24%), 25.1-50% in 10 (12%), and less than 25% in five patients (6%). Preoperatively, pituitary function was impaired in 12 patients (14%). Postsurgical SSA treatment lowered GH levels to less than 2.5 microg/liter in 49 (56%) and normalized IGF-I levels in 48 patients (55%). The success rate was significantly increased compared with that before surgery (P < 0.0001). GH (r = -0.48; P < 0.0001) and IGF-I levels (r = -0.38; P = 0.0003) after postsurgery SSA treatment correlated with the amount of tumor surgically removed. After surgery, pituitary function was impaired in 28 patients (32.6%) and was improved in 12 patients (13.9%). The cumulative prevalence of pituitary deficiency did not change during the study (normal function from 40 to 42%; deficiency from 60 to 58%).

CONCLUSIONS

Surgical tumor removal (>75%) enhances the response to SSAs without impairing pituitary function. Our data indicate that surgical debulking has a significant place in the treatment algorithm of acromegaly.

Long-term Primary Medical Therapy with Somatostatin Analogs in Acromegaly

To cure acromegalic patients, transsphenoidal surgery is considered first, especially for microadenoma. However, less than 50% of patients with macroadenoma achieve satisfactory biochemical control. Moreover, surgery may cause hypopituitarism. Medical therapy may offer the prospect of near normalization of growth hormone (GH)/insulin-like growth factor-1 levels with substantial tumor shrinkage in a significant number of patients. Here, we report two cases of acromegaly under treatment with somatostatin analogs alone for more than 10 years. Case 1 was a 54-year-old man with a pituitary macroadenoma. He received 4 years of octreotide treatment followed by 6 years of prolonged-release (PR) lanreotide resulting in normal GH level. Case 2 was a 60-year-old woman with a 1.3 cm pituitary tumor. She received 8 years of octreotide treatment followed by 6 years of PR lanreotide resulting in subnormal GH level and gallbladder sludge. She had received bilateral total hip replacement for hip osteoarthritis at the age of 59 years. These cases illustrate that long-term treatment with somatostatin analogs offers an alternative choice in selected acromegalic patients, such as those with pituitary tumor who cannot be cured by surgery, those who have unacceptable anesthetic risk and those who refuse surgery.

Clinical indicators of biochemical remission in acromegaly: does incomplete disease control always mean therapeutic failure?

OBJECTIVE

Correction of GH and IGF-I levels are associated with improvements in insulin secretion, cardiac performance and body composition in patients with acromegaly, but whether these parallel post-treatment levels of GH-IGF-I axis activity is undefined. We investigate whether various biochemical outcomes after transsphenoidal pituitary surgery (TSS) in these patients are associated with clinically relevant differences in cardiac performance, insulin resistance and body composition.

DESIGN

Cross-sectional study of consecutive patients with acromegaly admitted to the hospital between 2001 and 2002.

PATIENTS AND METHODS

Forty-one patients after TSS for somatotroph pituitary adenoma and 23 patients with naive acromegaly serving as positive controls were enrolled in the study. Mean daily GH levels (mGH), IGF-I, leptin and lipid levels, glucose, insulin and GH concentrations during oral glucose tolerance test (oGTT) were measured in all study participants. Insulin resistance was measured by homeostatic model index (R(HOMA)). Body composition was assessed by dual-energy X-ray absorptiometry. Left ventricular mass index (LVM(i)) and cardiac index (C(i)) were determined by echocardiography.

RESULTS

We found no difference in cardiac indices, insulin resistance, body composition and leptin levels between patients with complete biochemical remission and those with inadequately controlled disease (P > 0.05 for all) after TSS. Cured patients had lower values (mean +/- SD) of cardiac index (2.2 +/- 0.7 vs. 3.0 +/- 1.0 l/min/m(2); P = 0.04) compared with naive patients. A similar decrease in LVM(i) was observed in controlled (108.4 +/- 30.0 g/m(2); P = 0.015) and inadequately controlled disease (108.8 +/- 30.7 g/m(2); P = 0.03) in comparison with naive disease (160.3 +/- 80.6 g/m(2)). Insulin resistance and leptin changed in opposite ways. In controlled and inadequately controlled disease, R(HOMA) index was lower (2.2 +/- 1.4; P = 0.001 and 3.1 +/- 2.0; P = 0.05 vs. 5.1 +/- 3.1) while leptin concentration was higher (14.9 +/- 8.7 microg/l, P = 0.004 and 12.8 +/- 7.8 microg/l, P = 0.05 vs. 7.4 +/- 3.8 microg/l) than in naive disease. In all patients, leptin correlated negatively with cardiac index (r = -0.46; P = 0.001) and IGF-I levels (r = -0.45; P < 0.001). Independent predictors of biochemical remission, based on normal IGF-I levels only, were cardiac [P = 0.04, odds ratio (OR) 0.4; 95% confidence interval (CI) 0.2-0.9] and R(HOMA) index (P = 0.009, OR 0.6; 95% CI 0.4-0.8). Similar results were obtained if the definition of cure included both normal IGF-I levels and the ability to achieve GH nadir < 1 microg/l during oGTT. Insulin resistance (P = 0.02, OR 0.6; 95% CI 0.4-0.9) and leptin level (P = 0.002, OR 1.3; 95% CI 1.1-1.6) were independent predictors of normalized mGH values.

CONCLUSION

This study shows that cardiac indices, insulin resistance and body composition were not different between patients with complete biochemical remission and those with discordant GH and IGF-I levels. It appears that even incomplete disease control after TSS can result in improvement of these clinical markers.

Long-term treatment of acromegaly with lanreotide: evidence of increased serum parathormone concentration

The somatostatin analogue lanreotide is effective in reducing growth hormone levels in patients with acromegaly. Acromegaly is characterized by calcium homeostasis alterations. The aim of our study was to evaluate the effects of lanreotide on bone turnover markers in a group of acromegalic patients and to verify a possible increase of intact parathormone (iPTH) levels in a transient or persistent way. Serum GH, IGF-I and serum and urinary markers of bone metabolism were measured before treatment and on months 3 and 24. In short-term treatment (3 months), lanreotide significantly decreased GH, IGF-I, serum calcium, osteocalcin and alkaline phosphatase levels, but increased iPTH level (49 +/- 16.7 vs pre-treatment 28.3 +/- 7.6 ng/L, p<0.001). During long-term study (24 months) GH and IGF-I were significantly still low; serum calcium and alkaline phosphatase levels returned to pre-treatment levels. iPTH level was significantly still higher compared with pre-treatment (46.4 +/- 9.2 vs 28.3 +/- 7.6 ng/L, p<0.05). No changes were seen in serum albumin, creatinine and vitamin D during short and long term treatment. The changes of most bone markers during lanreotide treatment can be explained by the decrease of GH and IGF-I. The increase of iPTH concentration suggests that lanreotide has ulterior and long-standing actions on calcium homeostasis: intestinal malabsorption of calcium due to the lanreotide could contribute to this "secondary" hyperparathyroidism. The clinical relevance of these long-standing effects needs to be further investigated.

One-year follow-up of patients with acromegaly treated with fixed or titrated doses of lanreotide Autogel

OBJECTIVE

Somatostatin analogue treatment is first-line medical therapy for acromegaly. This study compared the efficacy and tolerability of titrated doses of the long-acting somatostatin analogue preparation lanreotide Autogel with fixed doses and with lanreotide prolonged release (PR) 30 mg microparticles.

PATIENTS

Patients entering the initial study had received a diagnosis of active acromegaly within the previous 5 years.

DESIGN

This open, comparative, multicentre study was a 1-year extension of a previous trial during which patients with acromegaly had switched from lanreotide PR 30 mg microparticles injected intramuscularly every 7, 10 or 14 days, for at least 3 months, to one of three fixed doses of lanreotide Autogel (120, 90, or 60 mg every 28 days, respectively). In this extension study, patients continued to receive 60, 90, or 120 mg of lanreotide Autogel by deep subcutaneous injection every 28 days for 1 year. Doses could be titrated at entry or after four or eight injections, according to the GH/IGF-I response (dose increased if GH > 2.5 micro g/l, or decreased if GH < 1 micro g/l with normal IGF-I).

MEASUREMENTS

Mean +/- SEM GH and IGF-I concentrations were analysed and gallbladder echography performed at weeks 0, 16, 32, and 48. Acromegaly symptoms were recorded monthly and tolerance and side-effects were monitored throughout the study.

RESULTS

In total, 130 patients entered this extension phase. After 1 year of treatment with titrated doses of lanreotide Autogel, mean GH (2.4 +/- 0.2 micro g/l) and IGF-I (287 +/- 12 micro g/l) concentrations were significantly lower than with lanreotide microparticles (GH, 2.8 +/- 0.2 micro g/l, P < 0.001; IGF-I, 332 +/- 15 micro g/l, P < 0.01) or with fixed-dose lanreotide Autogel (GH, 3.0 +/- 0.2 micro g/l, P < 0.001; IGF-I, 310 +/- 14 micro g/l, P = 0.02). GH hypersecretion was reduced to </= 2.5 micro g/l in 68% of patients with titrated-dose lanreotide Autogel compared with 49% with microparticles (P < 0.001) and 56% with fixed-dose lanreotide Autogel (P </= 0.005). In the 65 patients who did not require any dose titration, there was no substantial change in serum lanreotide concentration, GH or IGF-I levels over the 12-month study duration. Acromegaly was effectively controlled (GH </= 2.5 micro g/l and normalized IGF-I) in significantly more patients (43%) compared with microparticles (32%; P < 0.05). There was a trend for improved control of acromegalic symptoms with dose titration, whereas the incidence of gastrointestinal symptoms and local tolerance was similar with lanreotide Autogel and lanreotide microparticles. Gallbladder echographies showed new lithiasis in 8% of lanreotide Autogel patients.

CONCLUSION

Dose titration of lanreotide Autogel improved GH and IGF-I control in patients with acromegaly beyond that achieved using fixed doses of lanreotide Autogel or lanreotide microparticles. Titrated long-term lanreotide Autogel treatment is well tolerated.

Pharmacokinetics of a new Autogel formulation of the somatostatin analogue lanreotide after a single subcutaneous dose in healthy volunteers

The pharmacokinetics/tolerability of lanreotide Autogel have been evaluated. Healthy volunteers (n = 24) first received immediate-release lanreotide as a single subcutaneous (s.c.) injection. After two days, 40 or 60 mg lanreotide Autogel was injected subcutaneously. Blood was sampled at various intervals for 56 days. Systemic/local adverse events and changes in biological profile/vital signs were recorded. Lanreotide Autogel produced a prolonged-release pharmacokinetic profile: mean area under the serum concentration-time curve from time 0 to infinity (AUC) was 53.73 +/- 8.99 and 79.48 +/- 13.06 ng mL(-1) day for 40 and 60 mg, respectively, mean peak serum concentration (C(max)) was 4.38 +/- 2.91 and 5.71 +/- 3.52 ng mL(-1), respectively, median time to reach C (minimum-maximum) was 0.50 (0.083-18.0) and 0.38 (0.083-9.01) days, respectively, mean apparent elimination half-life was 21.63 +/- 9.42 and 22.01 +/- 9.87 days, respectively, and relative bioavailability was 0.93 +/- 0.12 and 0.82 +/- 0.15, respectively. Thus, lanreotide Autogel exhibited linear pharmacokinetics for the doses studied. Pharmacokinetic profiles were similar in both genders, apart from statistically significant differences in C(max) and C(max)/AUC. The Autogel formulation of lanreotide was well tolerated, with systemic adverse events being mild/moderate. Erythema and a painless subcutaneous induration were the most common local adverse events. Lanreotide Autogel provided a prolonged dosing interval and good tolerability for treating acromegaly and carcinoid syndrome.

Lanreotide 60 mg, a new long-acting formulation: effectiveness in the chronic treatment of acromegaly

Lanreotide (LAN) 60 mg (LAN60), a new long-acting formulation of LAN alleged to suppress GH/IGF-I hypersecretion for 28 d in acromegalic patients, was administered in a prospective open multicenter study to 92 patients with active acromegaly (61 women and 31 men, aged 20-79 yr). LAN60 was given as adjuvant treatment (AT) in 62 patients; the other 30 patients [primary treatment (PT)] were de novo (n = 20) or previously treated only by pharmacotherapy (n = 10). After wash-out from previous treatments, LAN60 was started im every 28 d for 3 injections; the dose was then individually tailored, aiming at lowering GH to less than 2.5 micro g/liter and IGF-I to the normal range. After a median follow-up of 24 months (range, 6-48 months), IGF-I normalized in 65% of patients, decreasing from 199 +/- 8% (expressed as a percentage of the upper limit of normal range; mean +/- SE) to 87 +/- 4% (P < 0.0001). GH fell to less than 2.5 microg/liter in 63% of patients and to less than 1 microg/liter in 25%, decreasing from 20 +/- 3 to 3 +/- 0.4 microg/liter (P < 0.0001). A progressive increase in the rate of IGF-I normalization was observed (from 49% at 1 yr to 77% at 3 yr). The rate of GH/IGF-I normalization was 72% at 36 months by Kaplan-Meier analysis. No tachyphylaxis was observed throughout the study. Shortening the interval between injections to 21 d improved GH/IGF-I suppression. PT and AT patients achieved similar final GH/IGF-I levels and rates of normalization. Tumor shrank in 39% of assessable patients and in 50% of PT. Plasma glucose levels did not change, and high density lipoprotein cholesterol increased (by 19.3 +/- 5.1%; P = 0.0215). Gallstones appeared or worsened in 13% of patients. LAN60 is a new, very effective and long-lasting formulation for the treatment of acromegaly. The persistence of a powerful suppression of GH/IGF-I levels, the progressive increase in the rate of IGF-I normalization, and the similarity in the efficacy achieved in PT and AT patients point to a role for LAN60 in the primary treatment of acromegaly.

Optimizing control of acromegaly: integrating a growth hormone receptor antagonist into the treatment algorithm

Acromegaly is associated with significant morbidities and a 2- to 3-fold increase in mortality because of the excessive metabolic action of GH and IGF-I, a marker of GH output. Reductions in morbidity correspond with decreases in IGF-I, and mortality is lowered following normalization of IGF-I or GH levels. Therefore, this has become an important end point. Current guidelines for the treatment of acromegaly have not considered recent advances in medical therapy, in particular, the place of pegvisomant, a GH receptor antagonist. Treatment goals include normalizing biochemical markers, controlling tumor mass, preserving pituitary function, and relieving signs and symptoms. Surgery reduces tumor volume and is considered first-line therapy. Radiation reduces tumor volume and GH and IGF-I levels, but the onset of action is slow and hypopituitarism typically develops. Therefore, pharmacotherapy is often used following surgery or as first-line therapy for nonresectable tumors. Dopamine agonists can be considered in patients exhibiting minimal disease or those with GH-prolactin-cosecreting tumors but will not achieve hormone normalization in most patients. Somatostatin analogs effectively suppress GH and IGF-I in most patients, but intolerance (e.g. diarrhea, cramping, gallstones) can occur. Pegvisomant, the newest therapeutic option, blocks GH action at peripheral receptors, normalizes IGF-I levels, reduces signs and symptoms, and corrects metabolic defects. Pegvisomant does not appear to affect tumor size and has few adverse effects. Pegvisomant is the most effective drug treatment for acromegaly in normalizing IGF-I and producing a clinical response; it is the preferred agent in patients resistant to or intolerant of somatostatin analogs.

How effective are current therapies for acromegaly?

Currently available therapies for acromegaly are transsphenoidal surgery (TSS), radiotherapy (RT) and medical therapy with the dopamine agonists and somatostatin analogues. The goals of these therapies for acromegaly are to normalize excessive hormone secretion, thus normalizing serum levels of growth hormone (GH) and of insulin-like growth factors (IGF-I), to reduce the clinical signs and symptoms of acromegaly and to reduce tumor size in order to relieve any symptoms due to tumor mass effect. These goals should be accomplished while preserving pituitary function and with as few side effects as possible.TSS, the initial choice of therapy in most patients, is the most effective therapy at reducing the signs and symptoms of mass effect such as visual or neurological compromise. TSS is potentially curative, but the outcome is highly dependent on the tumor size, the degree of tumor invasion and the expertise of the surgeon. TSS can achieve biochemical control with normalization of IGF-I in 80-90% of patients with microadenomas and in 50-60% of those with macroadenomas. RT may be used as adjunctive therapy after unsuccessful surgery. RT can lower GH levels and normalize IGF-I levels, but there is a long lag time before this effect is achieved. Biochemical control is not achieved for 6-10 years after conventional fractionated RT; the time to clinical effect after gamma knife RT seems to be shorter. The most common complication after all forms of RT for acromegaly is the development of new hypopituitarism. Medical therapy has assumed the major role as adjunctive therapy of acromegaly. The dopamine agonists used for the therapy of acromegaly include bromocriptine, quinagolide and cabergoline. Cabergoline seems to be the most efficacious of the dopamine agonists for the treatment of acromegaly, with normalization of IGF-I being achieved in up to 35% of patients treated. Dopamine agonists are generally not effective at reducing the size of pure GH-secreting pituitary tumors. Somatostatin analogues are the most effective medical therapy currently available for acromegaly. The clinically available long-acting somatostatin analogues are long-acting octreotide and slow-release lanreotide. Overall, IGF-I levels normalize in about 66% of patients treated with long-acting octreotide and in 48% of patients treated with lanreotide. About 30% of GH-secreting tumors treated with somatostatin analogues as adjunctive therapy will have some shrinkage, and the amount of shrinkage usually ranges between 20 and 50% of tumor size. Signs and symptoms of the disease improve in about two-thirds of patients treated with long-acting somatostatin analogues. Gastrointestinal side effects are common when initiating somatostatin analogue therapy, but these effects do not typically limit continued use. Multi-modality therapy for acromegaly is often needed to achieve disease control. However, even combinations of currently available therapies cannot achieve all the goals of therapy in many patients with acromegaly.

Somatostatin analogs as primary medical therapy for acromegaly

Acromegaly is a debilitating disease usually caused by a growth-hormone secreting pituitary adenoma. Therapeutic goals include improvement of symptoms, reduction in tumor mass, biochemical normalization, and preservation of pituitary function. Treatment options include transsphenoidal surgery, radiation, and pharmacotherapy. In view of the good cure rate, surgery remains the therapeutic modality of choice for most patients with microadenomas or well-circumscribed macroadenomas. In contrast, >40% of patients with invasive macroadenomas (who make up the majority of patients with acromegaly) will have residual disease following surgery, and require additional therapeutic intervention. Somatostatin analogs result in biochemical normalization in >60% of non-operated patients, and are well tolerated. Therefore, somatostatin analogs have emerged as a rational first-line treatment for the appropriately selected patient with acromegaly.

Primary medical therapy for acromegaly

There is now considerable evidence that the clinical outcome in patients with acromegaly can be improved very substantially by means of better surgical expertise and effective medical therapies used in a flexible and innovative manner. Medical therapy alone in patients who have not undergone surgery or radiotherapy (primary medical therapy) offers the prospect of near normalisation of GH/IGF-I levels together with substantial tumour shrinkage in a significant number of patients.

Modern treatment of acromegaly

Acromegaly is an endocrine disorder characterised by increased morbidity and mortality. It is usually caused by a growth hormone secreting pituitary adenoma and is manifested by a variety of clinical features. Surgery is usually the treatment of choice, however over the last few years, several new methods of treatment have been developed. A recent consensus on the targets for treatment has led to multiple studies being conducted to assess the efficacy of the currently available options. This review examines the evidence for and against these treatments.

Long-term treatment of acromegaly with pegvisomant, a growth hormone receptor antagonist

BACKGROUND

Pegvisomant is a new growth hormone receptor antagonist that improves symptoms and normalises insulin-like growth factor-1 (IGF-1) in a high proportion of patients with acromegaly treated for up to 12 weeks. We assessed the effects of pegvisomant in 160 patients with acromegaly treated for an average of 425 days.

METHODS

Treatment efficacy was assessed by measuring changes in tumour volume by magnetic resonance imaging, and serum growth hormone and IGF-1 concentrations in 152 patients who received pegvisomant by daily subcutaneous injection for up to 18 months. The safety analysis included 160 patients some of whom received weekly injections and are excluded from the efficacy analysis.

FINDINGS

Mean serum IGF-1 concentrations fell by at least 50%: 467 mg/L (SE 24), 526 mg/L (29), and 523 mg/L (40) in patients treated for 6, 12 and 18 months, respectively (p<0.001), whereas growth hormone increased by 12.5 mg/L (2.1), 12.5 mg/L (3.0), and 14.2 mg/L (5.7) (p<0.001). Of the patients treated for 12 months or more, 87 of 90 (97%) achieved a normal serum IGF-1 concentration. In patients withdrawn from pegvisomant (n=45), serum growth hormone concentrations were 8.0 mg/L (2.5) at baseline, rose to 15.2 mg/L (2.4) on drug, and fell back within 30 days of withdrawal to 8.3 mg/L (2.7). Antibodies to growth hormone were detected in 27 (16.9%) of patients, but no tachyphylaxis was seen. Serum insulin and glucose concentrations were significantly decreased (p<0.05). Two patients experienced progressive growth of their pituitary tumours, and two other patients had increased alanine and asparate aminotransferase concentrations requiring withdrawal from treatment. Mean pituitary tumour volume in 131 patients followed for a mean of 11.46 months (0.70) decreased by 0.033 cm(3) (0.057; p=0.353).

INTERPRETATION

Pegvisomant is an effective medical treatment for acromegaly.