Clinical and biochemical response following withdrawal of a long-acting, depot injection form of octreotide (Sandostatin-LAR)

Persistent remission of acromegaly in a patient with GH-secreting pituitary adenoma: Effect of treatment with pasireotide long-acting release and consequence of treatment withdrawal

WHAT IS KNOWN AND OBJECTIVE

Somatostatin analogues (SSAs) have been used for the treatment of acromegaly for several decades. However, a unified conclusion on the duration of SSAs therapy or the possibility of medication withdrawal is still missing. We aimed to report a case of acromegaly cured by pasireotide long-acting release (PAS-LAR) and provide some information on the withdrawal of SSAs after stable regression in acromegalic patients.

CASE SUMMARY

A 55-year-old male patient, who was diagnosed with acromegaly and refused surgery and received PAS-LAR as initial treatment, had maintained stability for ten years under the regular treatment with PAS-LAR. The pituitary microadenoma was also decreased during the treatment. After the PAS-LAR discontinuation for 21 months, no evidence of biochemical or clinical recurrence was found in this patient.

WHAT IS NEW AND CONCLUSION

The use of PAS-LAR in a subset of naive-treatment patients is promising to induce long-term regression. A subgroup of patients with mild and well-controlled acromegaly might hope for perpetual remission after the withdrawal of medication.

Cost-Effectiveness and Efficacy of a Novel Combination Regimen in Acromegaly: A Prospective, Randomized Trial

CONTEXT

Combination therapy with somatostatin receptor ligand (SRL) plus pegvisomant for patients with acromegaly is recommended after a maximizing dose on monotherapy. Lower-dose combination regimens are not well studied.

OBJECTIVE

To compare cost-effectiveness and efficacy of 3 lower-dose combination regimens in controlled and uncontrolled acromegaly.

DESIGN AND SETTING

Prospective, randomized, open-label, parallel arm study at a tertiary referral pituitary center.

PATIENTS

Adults with acromegaly regardless of response to prior SRL and biochemical control status at baseline, stratified by an SRL dose required for insulin-like growth factor (IGF)-I normalization during any 3-month period within 12 months preceding enrollment.

INTERVENTION

Combination therapy for 24 to 32 weeks on arm A, high-dose SRL (lanreotide 120 mg/octreotide long-acting release [LAR] 30 mg) plus weekly pegvisomant (40-160 mg/week); arm B, low-dose SRL (lanreotide 60 mg/octreotide LAR 10 mg) plus weekly pegvisomant; or arm C, low-dose SRL plus daily pegvisomant (15-60 mg/day).

MAIN OUTCOME MEASURE

Monthly treatment cost in each arm in participants completing ≥ 24 weeks of therapy.

RESULTS

Sixty patients were enrolled and 52 were evaluable. Fifty of 52 (96%) demonstrated IGF-I control regardless of prior SRL responsiveness (arm A, 14/15 [93.3%]; arm B, 22/23 [95.7%]; arm C, 14/14 [100%]). Arm B was least costly (mean, $9837 ± 1375 per month), arm C was most expensive (mean, $22543 ± 11158 per month), and arm A had an intermediate cost (mean, $14261 ± 1645 per month). Approximately 30% of patients required pegvisomant dose uptitration. Rates of adverse events were all < 10%.

CONCLUSIONS

Low-dose SRL plus weekly pegvisomant represents a novel dosing option for achieving cost-effective, optimal biochemical control in patients with uncontrolled acromegaly requiring combination therapy.

Active postoperative acromegaly: sustained remission after discontinuation of somatostatin analogues

In patients with active acromegaly after pituitary surgery, somatostatin analogues are effective in controlling the disease and can even be curative in some cases. After treatment discontinuation, the likelihood of disease recurrence is high. However, a small subset of patients remains symptom-free after discontinuation, with normalized growth hormone (GH) and insulin-like growth factor (IGF1) levels. The characteristics of patients most likely to achieve sustained remission after treatment discontinuation are not well understood, although limited evidence suggests that sustained remission is more likely in patients with lower GH and IGF1 levels before treatment withdrawal, in those who respond well to low-dose treatment, in those without evidence of adenoma on an MRI scan and/or in patients who receive long-term treatment. In this report, we describe the case of a 56-year-old female patient treated with lanreotide Autogel for 11 years. Treatment was successfully discontinued, and the patient is currently disease-free on all relevant parameters (clinical, biochemical and tumour status). The successful outcome in this case adds to the small body of literature suggesting that some well-selected patients who receive long-term treatment with somatostatin analogues may achieve sustained remission.

Diagnosis, treatment and clinical perspectives of acromegaly

Acromegaly is an insidious disease of the pituitary caused by a growth hormone-secreting adenoma. Generally, the diagnosis is made rather late in the course of the disease. Currently, acromegaly can be cured in about half of the patients with the disease by expert surgery. The remainder of non-surgically cured patients often can be effectively treated with somatostatin analogs; either with the new generation of dopaminergic drugs or with Pegvisomant, a GH-receptor blocking agent. However, at the time of diagnosis many patients suffer from serious comorbidities, including hypertension, heart disease, arthrosis, sleep apnea and diabetes mellitus. Recent reports have shown that mortality risk can be normalized. Nevertheless, all efforts should be undertaken to treat comorbidities. New strategies for surgery and medical treatment are discussed.

Discontinuation of somatostatin analogs while acromegaly is in long-term remission

PURPOSE

We aimed to evaluate the disease activity of medically controlled patients with acromegaly after withdrawal of somatostatin receptor ligands (SRL).

METHODS

Sixteen patients who were on a stable dose of SRL for more than 2 years and had at least 1 year of remission were included in the study. Five patients were on 10 mg, four were on 20 mg and three were on 30 mg of octreotide; whereas for lanreotide, one was on 60 mg, two were on 90 mg, and one was on 120 mg. All patients had received SRL with 28-day intervals. Basal GH, IGF1, glucose-suppressed GH levels were measured with 3-month intervals for a total of 12 months after withdrawal. Sella MRI evaluation was obtained at 6-month intervals. If the nadir GH level after glucose suppression was >1 ng/ml or IGF1 was above the normal limits during the follow-up period, SRL was restarted.

RESULTS

Three months after stopping SRL, 10 (63%) had biochemical disease recurrence. After 12 months of follow-up, in total 13 (81%) of the patients recurred. The final basal GH levels before withdrawal, basal GH at month-3, and glucose suppressed GH levels were significantly lower in patients with sustained remission (p = 0.003, p < 0.001, and p = 0.001). Basal GH and glucose suppressed GH levels at month-3 were correlated with the basal GH levels at month-0 (r = 0.6, p = 0.008 and r = 0.5, p = 0.03).

CONCLUSION

The final GH levels prior to discontinuation of SRL should be taken into consideration in patients with acromegaly in long-term remission. Moreover, the first visit 3 months after withdrawal is critically important for determining the future status of remission.

Safety and efficacy of oral octreotide in acromegaly: results of a multicenter phase III trial

BACKGROUND

A novel oral octreotide formulation was tested for efficacy and safety in a phase III, multicenter, open-label, dose-titration, baseline-controlled study in patients with acromegaly.

METHODS

We enrolled 155 complete or partially controlled patients (IGF-1 <1.3 × upper limit of normal [ULN], and 2-h integrated GH <2.5 ng/mL) receiving injectable somatostatin receptor ligand (SRL) for ≥ 3 months. Subjects were switched to 40 mg/d oral octreotide capsules (OOCs), and the dose escalated to 60 and then up to 80 mg/d to control IGF-1. Subsequent fixed doses were maintained for a 7-month core treatment, followed by a voluntary 6-month extension.

RESULTS

Of 151 evaluable subjects initiating OOCs, 65% maintained response and achieved the primary endpoint of IGF-1 <1.3 × ULN and mean integrated GH <2.5 ng/mL at the end of the core treatment period and 62% at the end of treatment (up to 13 mo). The effect was durable, and 85 % of subjects initially controlled on OOCs maintained this response up to 13 months. When controlled on OOCs, GH levels were reduced compared to baseline, and acromegaly-related symptoms improved. Of 102 subjects completing the core treatment, 86% elected to enroll in the 6-month extension. Twenty-six subjects who were considered treatment failures (IGF-1 ≥ 1.3 × ULN) terminated early, and 23 withdrew for adverse events, consistent with those known for octreotide or disease related.

CONCLUSIONS

OOC, an oral therapeutic peptide, achieves efficacy in controlling IGF-1 and GH after switching from injectable SRLs for up to 13 months, with a safety profile consistent with approved SRLs. OOC appears to be effective and safe as an acromegaly monotherapy.

Can we predict long-term remission after somatostatin analog withdrawal in patients with acromegaly? Results from a multicenter prospective trial

Somatostatin analogs (SSAs) represent the mainstay of therapy in acromegaly. One of the potential disadvantages is the expected need to maintain therapy indefinitely in previously non-irradiated patients. The aim of this multicenter prospective open trial was to evaluate the likelihood of successful discontinuation of SSA therapy in well-controlled acromegalic patients who fulfilled very strict criteria: two or more years of treatment with the long-acting SSA octreotide LAR (OCT-LAR), a stable dose and injections interval every 4 weeks or longer for the previous year, GH levels <2.5 ng/ml and normal IGF-1 levels for age, a tumor remnant <10 mm, no history of radiotherapy, and no use of cabergoline or pegvisomant over the previous 6 months. Disease recurrence was defined as an increase of IGF-1 to levels above 1.2-fold the upper limit of normal (ULN). Out of 220 patients, 20 patients (12 women and 8 men; mean age, 48.1 ± 10.3 years; age range, 27-64) treated for 2.74 ± 0.64 years (range, 2.0-4.4) were included in this prospective study and OCT-LAR therapy was stopped. Four patients (20 %) remained without clinical and biochemical/neuroradiological evidence of disease recurrence after 12-18 months of follow-up. Sixteen patients (80 %) relapsed biochemically within 9 months after drug withdrawal and restarted OCT-LAR at the same previous dose. Compared to recurring subjects, non-recurring patients had significantly lower mean IGF-1 (× ULN) levels but there were some overlapping values in both groups. No other characteristic could be identified as a predictor of successful OCT-LAR discontinuation. Our findings demonstrated that OCT-LAR withdrawal, though rare, is possible in well-selected acromegalic patients treated for at least 2 years and considered optimally controlled in hormonal and neuroradiological terms.

Octreotide long-acting repeatable for acromegaly

Acromegaly remains a therapeutic challenge for the endocrinologist. Among the available therapeutic options, octreotide long-acting repeatable (Sandostatin(®) LAR(®), Novartis) plays a chief role, both as a primary therapy and as an adjuvant treatment after unsuccessful surgery. A plethora of papers and a meta-analysis have demonstrated its efficacy in: control of clinical picture; achievement of safe growth hormone and normal age-matched IGF-I levels (both factors associated with restoration of normal life expectancy) in 60-70% of patients; control of tumor volume (with real shrinkage in over half of cases); and halt or reversal of most acromegaly-associated comorbidities. Treatment is well tolerated in most patients and can be safely prolonged for many years if required.

Discontinuation of octreotide LAR after long term, successful treatment of patients with acromegaly: is it worth trying?

BACKGROUND

Somatostatin analogs (SA) have been used for over 25 years in the treatment of acromegaly. A major disadvantage is the need to continue therapy indefinitely.

OBJECTIVE

To evaluate the feasibility of discontinuing therapy in well-controlled patients with acromegaly treated chronically with SA.

DESIGN AND METHODS

Of the 205 subjects on octreotide LAR, we selected those who met the following criteria: two or more years of treatment, a stable dose and injection interval of 20  mg every 8 weeks or longer for the previous year, no history of radiation, no cabergoline for the previous 6 months, a GH <1.5  ng/ml, and an IGF1 <1.2×upper limit of normal (ULN). Octreotide LAR was stopped and both GH and IGF1 were measured monthly for 4 months; a glucose-suppressed GH value and magnetic resonance imaging were obtained at the 4th month, thereafter, basal GH and IGF1 were measured q. 3 months, for 12-18 months. Patients were removed from the study if GH or IGF1 rose to 1.5  ng/ml or 1.2×ULN respectively.

RESULTS

Twelve patients (ten women, mean age 48±13 years) were studied. Seven patients (58.3%) relapsed biochemically within 1 year of having stopped the SA; two patients relapsed by GH and IGF1 criteria, the remaining five patients kept GH levels within target. Five patients (41.7%) remain in remission after 12 months of follow-up. Non-recurring patients were on longer injection intervals but no other characteristic was associated with a successful withdrawal.

CONCLUSION

Withdrawal of SA is possible in a small but distinct subset of patients, particularly in those who are very well controlled on relatively low doses administered at long intervals.

Large fat and skin necroses after deep subcutaneous injections of a slow-release somatostatin analogue in a woman with acromegaly

OBJECTIVE

Somatostatin analogues are the most commonly used drugs for treatment of acromegaly. Known side effects include gastrointestinal reactions, cholelithiasis, effects on glucose metabolism, and mild reactions at injection sites. We report a patient who developed fat and skin necroses after injections of a depot somatostatin analogue.

SUBJECT

A woman with active acromegaly was given deep subcutaneous injections of an extended release formulation of lanreotide at alternate sides of the buttocks on three occasions over a ten week period. The regimen was then discontinued due to gastrointestinal complaints. One month later indurated subcutaneous nodules appeared at both sites. After another two months, the patient presented 10×10 cm lesions on the buttocks, with central erythematous zones and, at the site of two injections, a necrotic 5×3 cm ulcer. There were no signs of infection or systemic diseases. MRI revealed bilateral fat necroses. A month later, an ulcer developed at the second site. The ulcers were managed conservatively until clear demarcations were obtained, where after surgical revisions were performed. Eight months after the last injection, the wounds could be closed.

CONCLUSION

The fat and skin necroses represent a side-effect not previously described after deep subcutaneous injections. Possibly, the patient had an exceptional susceptibility to develop an inflammatory, foreign-body like reaction that hypothetically was aggravated by a sustained anti-angiogenic effect of the compound.

Octreotide LAR: safety and tolerability issues

BACKGROUND

Somatostatin analogues are the cornerstone in therapy of acromegaly and functioning neuroendocrine tumors. Long-acting retard formulations have improved patient survival and contributed considerably to quality of life. The first such compound was octreotide LAR ('long-acting release'), characterized by high affinity to somatostatin receptor subtypes 2 and 5, which has to be injected intramuscularly every 4 weeks.

OBJECTIVE

The aim was to screen all octreotide LAR-related literature and assess the compound's profile for safety and tolerability.

METHODS

An extensive literature search has been performed using the MEDLINE database to retrieve data from clinical studies evaluating the efficacy and tolerability of octreotide LAR.

RESULTS/CONCLUSION

Octreotide LAR is well tolerated; however, diarrhea and gallstone formation were identified as the main adverse events. Impairment of glucose homeostasis was a regular phenomenon, but its occurrence was unpredictable. General side effects such as headache, abdominal discomfort or fatigue were also reported. According to incidental case reports, administration during pregnancy appears to be safe for both mother and child; however, definitive evidence is missing. In addition, octreotide LAR has been evaluated for further indications including treatment of solid tumor entities, due to its antiproliferative effect. Currently, several compounds (lanreotide, SOM230) with a broader receptor spectrum are under evaluation and may improve treatment efficacy and lower incidence of side effects.

Long-term treatment of acromegalic patients resistant to somatostatin analogues with the GH receptor antagonist pegvisomant: its efficacy in relation to gender and previous radiotherapy

CONTEXT

Pegvisomant is an effective treatment for somatostatin analogue-resistant acromegaly, but the determinants defining the response to this treatment are largely unknown.

OBJECTIVE

To investigate the efficacy of pegvisomant treatment in resistant acromegalic patients (e.g. serum IGF1 at least 1.25 x upper normal limit) in a clinical setting and the factors conditioning this response.

DESIGN AND SETTING

A retrospective cross-sectional study performed in six Spanish University hospitals from 2004 to 2007. Patients Forty-four acromegalic patients (61.4% female, mean age: 49+/-14), 95% of whom had undergone pituitary surgery and 61% having received pituitary radiotherapy. The mean follow-up was 22.7+/-11.2 months. Main outcome measures IGF1 levels reflected treatment efficacy, and the influence of gender, age, weight, previous radiotherapy and duration of treatment was assessed.

RESULTS

IGF1 normalisation was achieved in 84% of the patients. Male gender (P<0.05), previous irradiation (P<0.05) and the treatment duration (r=0.364, P<0.02) were associated with a better response to pegvisomant therapy. There was a significant decrease in HbA1c (P<0.001) and in the mean insulin dose (P<0.01) in acromegalic diabetic patients. Although 25% of patients experienced mild adverse events, pegvisomant was only withdrawn in four patients due to side effects (two cases of tumour growth, one liver dysfunction and one headache).

CONCLUSIONS

Long-term pegvisomant is a very effective therapy in resistant acromegaly. Male gender and prior radiotherapy influence the therapeutic response rate.

Octreotide LAR for the treatment of acromegaly

BACKGROUND

Somatostatin analogs previously considered as adjuvant therapy in acromegaly are increasingly used as a first-line therapy in selected cases.

OBJECTIVE

To review the octreotide LAR pharmacological and clinical data, and discuss the impact of this agent on current treatment regimens.

METHODS

We reviewed PubMed publications since the first use of octreotide LAR in acromegaly, and historical articles related to the discovery and development of this molecule. We chose, for efficacy and safety data, reviews, clinical and randomized controlled trials that included >or=10 patients.

RESULTS/CONCLUSION

Octreotide LAR controls acromegaly in approximately 50-60% of patients by inhibiting GH and IGF-I secretion, and by reducing tumor size. This drug is well tolerated in most patients.

[Radiosurgery for pituitary adenomas]

Pituitary adenomas represent nearly 15% of all intracranial tumors. Multimodal treatment includes microsurgery, medical management and radiotherapy. Microsurgery is the primary recommendation for nonfunctioning and most of functioning adenomas, except for prolactinomas that are usually managed with dopamine agonist drugs. However, about 30% of patients require additional treatment after microsurgery for recurrent or residual tumors. In these cases, fractionated radiation therapy has been the traditional treatment. More recently, radiosurgery has been established as a treatment option. Radiosurgery allows the delivery of prescribed dose with high precision strictly to the target and spares the surrounding tissues. Therefore, the risks of hypopituitarism, visual damage and vasculopathy are significantly lower. Furthermore, the latency of the radiation response after radiosurgery is substantially shorter than that of fractionated radiotherapy. The goal of this review is to define the efficacy, safety and role of radiosurgery for treatment of pituitary adenomas and to present the preliminary results of our institution.

Preliminary data on biochemical remission of acromegaly after somatostatin analogs withdrawal

OBJECTIVE

It is still unknown whether prolonged treatment with somatostatin analogs (SSTa) may cause a long-lasting disease remission in GH-secreting adenomas after drug discontinuation. The aim of the present study was to investigate the evolution of GH/IGF-I secretion and tumor mass after SSTa withdrawal in patients affected by acromegaly.

PATIENTS AND DESIGN

A total of 27 patients with acromegaly (12 de novo and 15 previously operated) were treated with SSTa for a median period of 48 months and considered optimally controlled in hormonal and neuroradiological terms. None of them were previously irradiated.

METHODS

Basal GH, post-glucose GH nadir, IGF-I, clinical signs/symptoms, and metabolic parameters were evaluated after 12-16 weeks from drug withdrawal. Only patients who met the current criteria for disease remission remained in drug suspension being periodically re-evaluated for biochemical/clinical data and neuroradiological imaging.

RESULTS

After 12-16 weeks withdrawal, 15 of the 27 patients had disease relapse and restarted SSTa, while 12 were considered 'in disease remission' (44% of total). Glucose metabolism improved in both euglycemic and diabetic patients after short-term SSTa discontinuation. Only one of the ten patients who reached 24 weeks withdrawal showed biochemical disease recurrence. On the whole, five of the patients still in remission after 6 months have already prolonged the follow-up over 12 months (median: 24 months), without clinical and biochemical/neuroradiological evidence of disease recurrence.

CONCLUSIONS

These preliminary data indicate a successful withdrawal of SSTa at least in a subset of well-responsive patients with acromegaly and challenge the previously held concept that medical therapy is always a lifelong requirement.

Optimalization and cost management of lanreotide-Autogel therapy in acromegaly

BACKGROUND

Lanreotide-Autogel is a depot formulation of the somatostatin analog lanreotide used in the treatment of acromegaly. We investigated whether prolonging or shortening the interval between injections would offer any benefit.

SUBJECTS AND METHODS

The interval was prolonged from once every 4 weeks to once every 6 weeks when patients (n=9) had normal IGF-I and GH concentrations. When patients (n=12) had still elevated IGF-I or GH on the maximal dose of 120 mg every 4 weeks, the interval was shortened to once every 3 weeks. Serum IGF-I and GH were measured after 12 and 24 weeks to allow for dose adaptation. Symptoms and tumor volume were evaluated at baseline and after 36 weeks.

RESULTS

In seven of the nine subjects with normal IGF-I and GH, the interval could be extended to 6 weeks without loosing efficacy on IGF-I (195 vs 213 microg/l; not significant, NS) and GH concentrations (1.4 vs 1.3 microg/l; NS). The weekly dose could significantly be reduced (from 23.3 to 17.8 mg; P=0.002). In only 1 of the 12 not-controlled patients, reducing the interval to once every 3 weeks induced normalization of IGF-I and GH.

CONCLUSION

In subjects whose acromegaly is well controlled using lanreotide-Autogel, prolonging the time interval between injections can often be increased 4 to 6 weeks without loss of efficacy, thereby improving the subject's comfort and reducing the cost of treatment. On the other hand, in subjects whose acromegaly is not controlled on a dose of 120 mg every 4 weeks, reducing the interval to every 3 weeks is rarely beneficial.

Withdrawal of somatostatin analogue therapy in patients with acromegaly is associated with an increased risk of acute biliary problems

BACKGROUND

The prevalence of gallstones (GS) is increased in acromegaly and further increased by somatostatin analogue (SA) therapy. The incidence is reported at 10-63%, but they are often asymptomatic and rarely require definitive management. Evidence suggests discontinuation of SA may precipitate acute biliary problems.

OBJECTIVE

To determine the frequency of symptomatic gallstones in patients treated with SA.

DESIGN

Retrospective analysis of prospectively followed patients in our centre.

RESULTS

Fifty patients (30 male, mean age 54 +/- 16 years) were on treatment with SA on 1 January 2003. Fifteen (11 male, mean age 50 +/- 17 years) have since discontinued SA with three proceeding to develop acute cholecystitis and two, biliary colic necessitating cholecystectomy. Three of the five had abnormal liver enzymes at or within 3 months of symptomatic presentation. Two of the remaining 35 patients experienced biliary colic necessitating cholecystectomy. These data indicate a highly significant increase in acute biliary problems on discontinuing SA (5 in 27.67 patient 'off-treatment' years vs. 2 in 299 patient treatment years, chi(2), P < 0.0001). All seven patients experiencing problems were male (P = 0.01).

CONCLUSION

This analysis demonstrates the high incidence of symptomatic GS following SA withdrawal, particularly in men. Although liver enzymes were raised no common abnormality was evident to aid as a predictor of future symptoms. We recommend all patients due to stop SA be forewarned of the risk of acute biliary problems. Further work is required to confirm if there is a gender-related difference in the incidence of acute biliary problems on discontinuing SA therapy.

Octreotide for acromegaly

Octreotide has dramatically changed the results of medical treatment of acromegaly. It is the reference drug for the pharmacological treatment of acromegaly, owing to its impressive efficacy in suppressing growth hormome secretion, and excellent compliance. Safe growth hormone and normal insulin-like growth factor I values are reached in 50-60% of unselected patients. Octreotide arrests the growth of the tumor and shrinks tumor in over half of all patients (namely, up to 88% of naive patients and to complete disappearance in anecdotic cases). The safety profile of octreotide is excellent, but in some patients, glucose metabolism worsens and cholelythiasis occurs. This review will address the primary treatment and the relative roles of pharmacological and surgical treatment, as well as the predictivity of octreotide results.

Age changes the diagnostic accuracy of mean profile and nadir growth hormone levels after oral glucose in postoperative patients with acromegaly

BACKGROUND

This analytical, retrospective study was designed to select cut-off thresholds of mean GH levels during a diurnal profile and nadir GH levels after oral glucose tolerance test (OGTT) according to age to diagnose surgical remission of acromegaly.

METHODS

One hundred forty-one patients (76 women, aged 44 +/- 15 years and 65 men, aged 43 +/- 13 years) were included in this study. For the purpose of this study, remission was based on insulin-like growth factor-I (IGF-I) levels in the normal range for age. Diagnostic accuracy was analysed by receiving-operator characteristics (ROC) curves in the entire series, and in young (20-40 years), middle-aged (41-60 years) and older patients (> 60 years), separately.

RESULTS

Sixty patients (42.6%) had normal IGF-I levels after surgery. In the entire series, in young and in middle-aged patients, the ROC analysis showed that optimum cut-off for mean GH levels was 2.3 microg/l (diagnostic accuracy range, 94-97%) whereas that for nadir GH after OGTT were, respectively, 0.85, 0.9 and 0.8 microg/l (diagnostic accuracy range, 90-95%). In the older patients, the optimum cut-off selected for mean GH levels was 1.4 microg/l and that for nadir GH after OGTT was 0.5 microg/l (diagnostic accuracy, 100% for both). The comparative analysis of the ROC curves did not show any significant difference between mean GH and nadir GH after OGTT (P = 0.21).

CONCLUSIONS

The criteria currently accepted for diagnosing post-surgical remission of acromegaly have high diagnostic accuracy only in the patients aged below 60 years. In older patients, lower cut-offs (i.e. = 1.4 microg/l for fasting GH and = 0.5 microg/l for nadir GH after OGTT) predict normal IGF-I levels. Mean GH levels during a diurnal profile have similar diagnostic accuracy of nadir GH levels after OGTT. This suggests that OGTT is not necessary to establish surgical cure.

Current pharmacotherapy for acromegaly: a review

Acromegaly is associated with considerable morbidity and excess mortality; however, after effective treatment, both morbidity and mortality risks improve. Growth hormone excess in acromegaly can be controlled in many patients by pharmacotherapy alone, and with a combination of transsphenoidal surgery and pharmacotherapy in almost all patients. Since the clinical introduction of pegvisomant, a growth hormone-receptor antagonist, the role of radiotherapy is restricted. This review focuses on the treatment options for acromegaly (e.g., surgery, radiotherapy and pharmacotherapy with the depot preparations of the somatostatin analogues octreotide long-acting release formulation, lanreotide slow-release formulation and lanreotide Autogel, the growth hormone antagonist pegvisomant and the dopamine agonist cabergoline). Pharmacological characteristics of these drugs and the clinical and adverse effects are discussed individually and in relation to the other treatment modalities. The evidence for biochemical goals aimed at during medical treatment and the costs of pharmacotherapy are discussed. A new treatment algorithm is proposed, in which the choice between primary medical treatment and primary surgery is individualised, dependent on adenoma size and extension, patient factors (age, preference for therapy, contraindication for surgery), surgical experience of the centre and octreotide sensitivity of the adenoma. The high cost of lifelong medical treatment, especially of pegvisomant, must be weighed against the cost of a single surgical procedure.

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.

Systematic dose-extension of octreotide LAR: the importance of individual tailoring of treatment in patients with acromegaly

OBJECTIVE

The depot long-acting somatostatin analogue octreotide LAR (LAR) provides effective and well-tolerated treatment for acromegaly. Despite a 4-weekly recommended injection frequency, prolonged duration of GH suppression has been observed in some patients following treatment with long-acting somatostatin analogues. The aim of our study was to perform a prospective systematic study to determine whether extending the interval between doses of LAR allows maintenance of 'safe' GH in selected patients with acromegaly.

PATIENTS AND METHODS

Twenty-two patients (15 men, seven women), mean age 58.9 years (35-81 years) with active acromegaly (mGH > 5 mU/l), requiring treatment were selected to receive treatment with LAR. Eleven patients had received previous treatment with both transsphenoidal surgery and radiotherapy, while six had received surgery alone. All patients were commenced on treatment with 20 mg LAR intramuscularly (i.m.) every 4 weeks. Mean GH (mGH) was measured after three consecutive injections immediately prior to the fourth injection. The dose frequency was systematically reduced after every four injections if mGH < 5 mU/l. Once mGH > 5 mU/l, the dose frequency was increased and mGH reassessed.

RESULTS

The dosing interval was successfully increased to greater than 4 weeks in 20/22 patients (90.9%). Six of 22 (27.3%) were receiving injections every 8 weeks and 3/22 (13.6%) every 12 weeks. GH and IGF-I were lower on treatment compared with baseline (P < 0.01). There was no difference in individual mGH and IGF-I between the values on 4-weekly dosing and those at final dose frequency. There was no relationship between final dose frequency and either mean GH or IGF-I prior to LAR, patient age, or previous treatment. The percentage suppression following 100 micro g octreotide subcutaneously did not predict subsequent dose frequency of LAR. The drug cost if patients had continued at 4-weekly intervals would be UK pound 187 850, compared with UK pound 101 065 for the individually titrated dose frequency (P < 0.01). This represents a final cost of 53.8% of the 4-weekly injection price.

CONCLUSION

Individual tailoring of LAR administration maintains control of acromegaly, with reduced injection frequency and improved cost-effectiveness.

Octreotide long-acting release (LAR): a review of its use in the management of acromegaly

Octreotide long-acting release (LAR) is a somatostatin analogue designed for once monthly intramuscular injection. As with endogenous somatostatin, octreotide LAR inhibits secretion of growth hormone (GH) as well as various other peptide hormones. In the treatment of acromegaly, octreotide LAR effectively controlled the secretion of GH and insulin-like growth factor-1 (IGF-1) in about 55-70% of patients (n > 100) who had previously been treated with somatostatin analogues, a similar degree of control to that observed with subcutaneous octreotide and lanreotide slow release (SR). Progressive control of serum levels of GH and IGF-1 was achieved with octreotide LAR in clinical studies of up to 4 years' duration. In addition, primary therapy with octreotide LAR provided effective control of GH and IGF-1 secretion, particularly in patients with a pretreatment GH level <20 microg/L. The percentage of patients achieving a target serum GH level of <2-2.5 micro g/L or normal IGF-1 levels was significantly greater with octreotide LAR 10, 20 or 30 mg every 28 days than with lanreotide SR 30 mg every 7-14 days in a large (n = 125) sequential, 6-month study, but was not significantly different between treatment groups in a small, randomised, nonblind, parallel group study of previously untreated patients. The volume of pituitary tumour shrinkage achieved with octreotide LAR or lanreotide SR was also similar ( approximate, equals 33% after 24 months). Acromegaly symptoms, such as headache, increased perspiration, paraesthesia, fatigue and osteoarthralgia were improved during treatment with octreotide LAR or lanreotide SR. Overall, octreotide LAR is generally well tolerated by most patients. The incidence of gastrointestinal symptoms is about 30% but, in most cases, events are transient and mild to moderate. Gallbladder abnormalities (sediment, sludge, microlithiasis and gallstones) can occur, but only 1% have become symptomatic to date. The prevalence of biliary abnormalities did not change after switching from subcutaneous octreotide, or from lanreotide SR, to octreotide LAR. Glucose metabolism can be affected by octreotide LAR in some patients; about 15% become hyperglycaemic, usually mild in severity. In summary, octreotide LAR controls GH and IGF-1 secretion in about 55-70% of patients with acromegaly. Octreotide LAR is administered intramuscularly every 28 days, offering improved patient compliance and convenience over three-times-daily subcutaneous octreotide. Long-term therapy provides progressive control of serum GH and IGF-1 levels, and is generally well tolerated by most patients. Thus, for the medical management of acromegaly, octreotide LAR is an effective, well tolerated and convenient treatment option.

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.

Sandostatin LAR in acromegaly: a 6-week injection interval suppresses GH secretion as effectively as a 4-week interval

INTRODUCTION

Depot preparations of long-acting somatostatin analogues are being used increasingly in the treatment of GH hypersecretion in patients with acromegaly, either as primary treatment or as secondary treatment following incomplete surgery. In 60% of these patients, Sandostatin long-acting release (LAR), the depot preparation of octreotide, achieves effective suppression of serum GH (< 5 mU/l) and IGF-I levels. The advice is to administer Sandostatin LAR at 4-week intervals. After injection, serum octreotide shows an initial peak and thereafter maximal values between 14 and 42 days. There have been suggestions that the dose interval of this preparation could be increased, resulting in reduced costs, although this concept has not been confirmed by studies.

AIM OF THE STUDY

We performed a prospective, cohort study in patients with active acromegaly but with normal serum GH and IGF-I levels during Sandostatin LAR treatment to assess whether the dose interval could be safely increased from 4 to 6 weeks, without significant effect on serum GH concentrations or other biochemical and clinical markers of GH hypersecretion.

PATIENTS AND METHODS

Fourteen patients (seven males) with GH concentrations below 5 mU/l during Sandostatin LAR treatment entered an 8-week withdrawal study following an injection. Subsequently, during an interval study patients received injections at 6-week intervals (t = 0, 8, 14, 20, 26, 32, 38 and 44 weeks). Study parameters (fasting GH, average GH of eight plasma samples, IGF-I, and octreotide concentrations, symptoms score and quality-of-life score) were assessed 2, 4, 6 and 8 weeks following the first injection (withdrawal) and at 26 and 44 weeks (interval study) before the next injection.

RESULTS

During the withdrawal study, mean serum GH concentration increased significantly from 1.68 +/- 0.3 at 4 weeks to 2.57 +/- 0.5 mU/l at 6 weeks (P = 0.04, 4 vs. 6 weeks) and to 2.89 +/- 0.4 mU/l at 8 weeks (P < 0.001, 4 vs. 8 weeks). Mean serum GH concentration was below 5 mU/l in all patients at all time points, except for one patient at 8 weeks, and IGF-I levels remained normal in all patients. During withdrawal up to 8 weeks there was no significant change in serum IGF-I concentration, symptoms score or quality-of-life score. Mean serum octreotide decreased significantly from 1610 +/- 355 ng/l at 2 weeks to 1045 +/- 272 ng/l at 6 weeks (P = 0.002, 2 and 4 vs. 6 weeks) and to 559 +/- 147 ng/l at 8 weeks. In the interval study, one patient had mean serum GH above 5 mU/l associated with an increase in symptoms at 26 weeks and she was withdrawn from the study. The remaining 13 patients completed the 6-weekly injection study protocol and in the long term no significant changes in mean serum GH concentration, IGF-I concentration or symptom scores were observed (6 vs. 26 and 44 weeks). All patients had a mean serum GH concentration < 5 mU/l and serum IGF-I remained normal in 11 out of 14 patients at 26 weeks and nine out of 13 patients at 44 weeks. Moreover, the mean octreotide concentrations measured 6 weeks after a Sandostatin LAR injection did not decrease in the long term.

CONCLUSION

On the basis of serum GH concentrations, most patients with serum GH levels < 5 mU/l during Sandostatin LAR treatment using a 4-weekly schedule can be effectively treated with 6-weekly injections. However, during long-term treatment with 6-weekly injections, discordant IGF-I and GH results were observed in 30% of the patients and careful clinical monitoring is therefore required.

Optimizing Somatostatin Analog Therapy in Acromegaly

Somatostatin peptide analogs have revolutionized the medical treatment of patients with acromegaly. More recent deep intramuscular depot preparations have further improved control, with consistent suppression of growth hormone secretion and optimal lowering of insulin-like growth factor-1. Effective control of growth hormone should, with long-term use, reduce morbidity and mortality from acromegaly and has been shown to result in partial involution of the pituitary adenoma in the majority of treated patients. The currently available depot formulations allow for an injection frequency of 14 days (lanreotide LA 30mg) to 28 days (octreotide LAR 20mg) according to the manufacturers' recommendations. In clinical practice, dose titration by evaluating a growth hormone day profile prior to the next injection can extend the interval between injection (to 6 or even 8 weeks in certain individuals). This is especially true for octreotide LAR, which also has increased flexibility regarding dosage with a 10 and 30mg preparation. The annual 'drug cost' is broadly similar between the two formulations though the additional expenditure on nurse time and clinic visits incurred by an increased injection frequency is a significant consideration. Decreased injection frequency improves acceptability for the patient without a loss in treatment efficacy. A subjective return of typical acromegalic symptoms, such as sweating and headache, also seem to be useful in predicting the timing of the next injection. Other formulations and doses of lanreotide are currently being evaluated, but more interestingly, newer analogs with greater efficacy at the type 5 somatostatin receptor subtype, and pan-receptor analogs, are being developed. These peptides, in conjunction with the likely availability of a growth hormone receptor blocking agent (pegvisomant), will further expand the medical therapy options for patients with acromegaly.

Optimal dosage interval for depot somatostatin analogue therapy in acromegaly requires individual titration

BACKGROUND

The recent introduction of the depot somatostatin analogues octreotide LAR and lanreotide represent major advances in the medical treatment of acromegaly. However, it is uncertain whether the recommended dose intervals of 4 weeks and 10-14 days, respectively, are applicable to all patients.

AIMS

To determine the optimum intervals between depot injections of either octreotide LAR and lanreotide for the suppression of serum GH and IGF-I in patients with acromegaly. Twenty-seven patients with acromegaly were randomly allocated to receive either three injections at 4 week intervals of octreotide LAR (n = 18) or five injections at 14 day intervals of lanreotide (n = 11); two patients participated in both arms. Prior to the first injection, at 4 and 6 weeks after the last injection of LAR, and at 10, 14 and 21 days after the last injection of lanreotide, serum mean GH and IGF-I levels were measured.

RESULTS

In the LAR-treated group, at 4 and 6 weeks after the third injection 13 patients (72%) and 12 patients (67%), respectively, had a mean GH < 5 mU/l. IGF-I was normalized in 12 and 11 patients at these times. In the lanreotide-treated group, five (45%), four (36%) and three (27%) patients, respectively, had a GH < 5 mU/l at 10, 14 and 21 days after the last injection and eight, six and five patients had a normal serum IGF-I.

CONCLUSION

There is marked variability in individual patient responses to depot somatostatin analogues. The establishment of optimal drug intervals requires careful assessment. For octreotide LAR many patients may be as adequately controlled with 6 weekly injections as with 4 weekly injections. It is important to measure serum GH profiles at intervals after initiating therapy with these drugs to individualize doses for each patient and hence minimize cost.

Time course of GH and IGF-1 levels following withdrawal of long-acting octreotide in acromegaly

AIM

Several studies have demonstrated the efficacy of octreotide LAR administered intramuscularly at 4-week intervals in the treatment of acromegaly. In contrast, few data are available on the time course of GH and IGF-1 plasma levels following octreotide LAR withdrawal. This prompted us to study these parameters for up to 20 weeks following drug withdrawal in a group of 18 acromegalic patients treated for one year.

DESIGN AND PATIENTS

We studied 18 patients treated with octreotide LAR 10 mg (n = 2), 20 mg (n = 15) and 30 mg (n = 1) every 4 weeks for one year. GH (mean level during a 4-hour daily profile) and IGF-1 concentrations were measured at the end of treatment, just before the last injection (baseline) and then 15 +/- 2 weeks (first control) after the last injection. In patients with GH levels below 2.5 micrograms/L and/or normal IGF-1 at the first control, a second control was performed four to eight weeks later.

RESULTS

After one year of treatment with octreotide LAR, the mean plasma GH concentration was 1.91 +/- 1.25 micrograms/L (mean +/- SE) and the mean IGF-1 concentration was 440 +/- 251 micrograms/L. Among the 18 patients, 13 had mean plasma GH concentrations below 2.5 micrograms/L and seven could be considered as well-controlled (normal IGF1 and mean GH levels below 2.5 micrograms/L). After treatment withdrawal, the plasma GH concentration remained below 2.5 micrograms/L at the first and the second controls in 2 of the 13 (15%) patients with suppressed GH levels on baseline. Among the seven well-controlled patients on baseline (GH levels below 2.5 micrograms/L and normal IGF-1), one (15%) remained well-controlled, one (15%) kept GH levels below 2.5 micrograms/L but increased IGF-1 levels, and one (15%) kept normal IGF-1 levels but increased mean GH levels at the first control. This hormonal status remained unchanged at the second control in these 3 patients.

CONCLUSIONS

These results show long-lasting suppression of GH secretion after treatment withdrawal in some acromegalic patients treated for 12 months with octreotide LAR. The duration of GH suppression after treatment withdrawal is variable. Mean GH levels remained below 2.5 micrograms/L in 15% of our patients for up to 21 weeks following withdrawal of octreotide LAR. In practice, it may be preferable to wait several months after long-acting somatostatin analog withdrawal before reassessing hormone status. Owing this long-lasting effect, a dose reduction to 10 mg and/or a longer interval between injections could be considered for very good responders, as this would lead to considerable cost savings without affecting GH or IGF-1 control.

Modulation of 11beta-hydroxysteroid dehydrogenase isozymes by growth hormone and insulin-like growth factor: in vivo and in vitro studies

The interconversion of hormonally active cortisol (F) and inactive cortisone (E) is catalyzed by two isozymes of 11beta-hydroxysteroid dehydrogenase (11betaHSD), an oxo-reductase converting E to F (11betaHSD1) and a dehydrogenase (11betaHSD2) converting F to E. 11betaHSD1 is important in mediating glucocorticoid-regulated glucose homeostasis and regional adipocyte differentiation. Earlier studies conducted with GH-deficient subjects treated with replacement GH suggested that GH may modulate 11betaHSD1 activity. In 7 acromegalic subjects withdrawing from medical therapy (Sandostatin-LAR; 20-40 mg/month for at least 12 months), GH rose from 7.1 +/- 1.5 to 17.5 +/- 4.3 mU/L (mean +/- SE), and insulin-like growth factor I (IGF-I) rose from 43.0 +/- 8.8 to 82.1 +/- 13.7 nmol/L (both P < 0.05) 4 months after treatment. There was a significant alteration in the normal set-point of F to E interconversion toward E. The fall in the urinary tetrahydrocortisols/tetrahydocortisone ratio (THF+allo-THF/THE; 0.82 +/- 0.06 to 0.60 +/- 0.06; P < 0.02) but unaltered urinary free F/urinary free E ratio (a marker for 11betaHSD2 activity) suggested that this was due to inhibition of 11betaHSD1 activity. An inverse correlation between GH and the THF+allo-THF/THE ratio was observed (r = -0.422; P < 0.05). Conversely, in 12 acromegalic patients treated by transsphenoidal surgery (GH falling from 124 +/- 49.2 to 29.3 +/- 15.4 mU/L; P < 0.01), the THF+allo-THF/THE ratio rose from 0.53 +/- 0.06 to 0.63 +/- 0.07 (P < 0.05). Patients from either group who failed to demonstrate a change in GH levels showed no change in the THF+allo-THF/THE ratio. In vitro studies conducted on cells stably transfected with either the human 11betaHSD1 or 11betaHSD2 complementary DNA and primary cultures of human omental adipose stromal cells expressing only the 11betaHSD1 isozyme indicated a dose-dependent inhibition of 11betaHSD1 oxo-reductase activity with IGF-I, but not GH. Neither IGF-I nor GH had any effect on 11betaHSD2 activity. GH, through an IGF-I-mediated effect, inhibits 11betaHSD1 activity. This reduction in E to F conversion will increase the MCR of F, and care should be taken to monitor the adequacy of function of the hypothalamo-pituitary-adrenal axis in acromegalic subjects and in GH-deficient, hypopituitary patients commencing replacement GH therapy. Conversely, enhanced E to F conversion occurs with a reduction in GH levels; in liver and adipose tissue this would result in increased hepatic glucose output and visceral adiposity, suggesting that part of the phenotype currently attributable to adult GH deficiency may be an indirect consequence of its effect on tissue F metabolism via 11betaHSD1 expression.