Pharmacokinetics and population pharmacodynamic analysis of lanreotide Autogel

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

Targeting neuroendocrine tumors with octreotide and lanreotide: Key points for clinical practice from NET specialists

Octreotide and lanreotide are the two somatostatin analogs (SSA) currently available in clinical practice. They have been approved first to control the clinical syndrome (mainly carcinoid syndrome) associated with functioning neuroendocrine tumors (NET) and later for tumor growth control in advanced low/intermediate grade NET. Although evidence regarding their role, especially as antiproliferative therapy, has been increasing over the years some clinical indications remain controversial. Solicited by AIOM (Italian Association of Medical Oncology) a group of clinicians from various specialties, including medical oncology, endocrinology, and gastroenterology, deeply involved in NET for their clinical and research activity, addressed eight open questions, critically reviewing evidence and guidelines and sharing clinical take-home messages. The questions regarded the use of long-acting octreotide and lanreotide in the following settings: functioning and non-functioning NET refractory to label dose, first-line metastatic pulmonary NET, combination with other therapy with an antiproliferative intent, maintenance in NET responding to other therapies, adjuvant treatment, Ki-67-related cut-off, somatostatin receptor imaging, safety, and feasibility. The level of evidence is not absolute for the majority of these clinical contexts, so it is recommended to distinguish routine versus sporadic utilization in very selected cases. Mention of such specific issues by the main European guidelines (ENETS, European Neuroendocrine Tumor Society, and ESMO, European Society for Medical Oncology) was explored and their position reported. However, different clinical decisions on single patients could be made if the case is carefully discussed within a NET-dedicated multidisciplinary team.

Pharmacological and safety profile of a prolonged-release lanreotide formulation in acromegaly

BACKGROUND

Patients with acromegaly require lifelong medication; a longer dosing interval would reduce treatment burden. This study investigated the pharmacokinetics, pharmacodynamics and safety profile of a new prolonged-release formulation (PRF) of lanreotide every 12 weeks.

RESEARCH DESIGN AND METHODS

In this multicenter, open-label, dose-ascending study, cohorts of nine patients with acromegaly received single doses of lanreotide PRF according to a 3 + 3 + 3 scheme in order to determine the maximum tolerated dose (MTD). Following a 12-week treatment period, patients were followed up for a further 12 weeks. Serum lanreotide, insulin-like growth factor-1 and growth hormone concentrations were analyzed. Adverse events were monitored throughout the study.

RESULTS

The MTD was not reached. Peak lanreotide serum concentration values were similar in all cohorts, whereas area under the curve values from time zero to 85 days increased but were not dose-proportional. The apparent elimination half-life of lanreotide PRF was approximately 54-63 days, in line with the expected prolonged-release characteristics. Growth hormone and insulin-like growth factor-1 levels were generally stable.

CONCLUSIONS

The safety and tolerability profile was in-line with the known safety profile of lanreotide autogel. Lanreotide PRF was well tolerated and the pharmacokinetic profile suggests that a dosing interval of 12 weeks could be achievable.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT02396953; EudraCT 2014-002389-62.

General lack of structural characterization of chemically synthesized long peptides

Many peptide chemistry scientists have been reporting extremely interesting work on the basis of chemical peptides for which the only characterization was their purity, mass, and biological activity. It seems slightly overenthusiastic, as many of these structures should be thoroughly characterized first to demonstrate the uniqueness of the structure, as opposed to the uniqueness of the sequence. Among the peptides of identical sequences in the final chemical preparation, what amount of well-folded peptide supports the measured activity? The activity of a peptide preparation cannot prove the purity of the desired peptide. Therefore, greater care should be taken in characterizing peptides, particularly those coming from chemical synthesis. At a time when the pharmaceutical industry is changing its paradigm by moving substantially from small molecules to biologics to better serve patients' needs, it is important to understand the limitations of the descriptions of these products and to start to apply the same "good laboratory practices" to our peptide research. Here, we attempt to delineate how synthetic peptides are described and characterized and what will be needed to describe them in regards to how they are well-folded and homogeneous in their tertiary structure. Older studies were done when the tools were not yet discovered, but more recent publications are still lacking proper descriptions of these peptides. Modern tools of analysis are capable of segregating folded and unfolded peptides, even if the preparation is biologically active.

Long-acting somatostatin analogues in the treatment of unresectable/metastatic neuroendocrine tumors

Neuroendocrine tumors (NETs) are a relatively rare and heterogeneous group of neoplasms with an annual incidence of ~35 cases per 100,000 people in the United States. The updated World Health Organization (WHO) classification system of gastroenteropancreatic (GEP)-NETs categorizes these tumors according to site of origin, clinical syndrome, and degree of differentiation. Well-differentiated NETs arising from the gastrointestinal tract or lungs (formerly known as carcinoid tumors) are often indolent and slow-growing. In contrast, poorly differentiated neuroendocrine carcinomas (NECs) are aggressive and have a poor prognosis. Due to their insidious onset, most NETs are diagnosed at an advanced stage and a curative approach is not possible. In these patients, medical therapy is limited to disease control, including relief of symptoms that arise from overproduction of peptide hormones by the tumors. Somatostatin analogues (SSAs) have remained the mainstay of symptoms control. In addition to symptoms control, clinical data also support an anti-proliferative effect of SSAs in patients with well- to moderately differentiated NETs. Long-acting SSAs have greatly facilitated their use. This review will focus on two long-acting SSAs, octreotide LAR and lanreotide, and their use in the clinical setting. Information necessary to assess their relative merits is summarized. We conclude these two therapies are interchangeable making value a very important consideration in their use.

Lanreotide autogel in acromegaly - a decade on

INTRODUCTION

The novel formulation of lanreotide, lanreotide (LAN) autogel (ATG), has been available in Europe since 2001 and USA from 2006 for the treatment of acromegaly. It is one of only two clinically available somatostatin analogs available for use in acromegaly. Data relating to the use of ATG in acromegaly, specifically relating to comparison to octreotide (OCT) LAR and patient acceptability and preference, have been slow to accumulate.

AREAS COVERED

We performed a comprehensive review of the original literature relating to development, pharmacokinetics, acceptability and clinical efficacy of ATG.

EXPERT OPINION

LAN ATG is a novel formulation of LAN consequent on self-assembly of nanotubules in water. Diffusion between molecules within the nanotubules and surrounding tissue fluid in vivo leads to pseudo first-order pharmacokinetics. Efficacy is equivalent to the alternate long-acting somatostatin analog, OCT LAR, normalizing growth hormone and IGF-I levels in around 60 and 50% respectively. Control of tumor growth is observed in over 95% of patients, with 64% seeing a clinically significant reduction in tumor size. ATG is provided in a prefilled syringe for deep subcutaneous injection, allowing self-injection, and may be administered up to 8 weeks greatly improving convenience for the patient. The data strongly support consideration of ATG as the medical therapy of choice for patients with acromegaly.

Clinical applications of somatostatin analogs for growth hormone-secreting pituitary adenomas

Excessive growth hormone (GH) is usually secreted by GH-secreting pituitary adenomas and causes gigantism in juveniles or acromegaly in adults. The clinical complications involving cardiovascular, respiratory, and metabolic systems lead to elevated morbidity in acromegaly. Control of serum GH and insulin-like growth factor (IGF) 1 hypersecretion by surgery or pharmacotherapy can decrease morbidity. Current pharmacotherapy includes somatostatin analogs (SAs) and GH receptor antagonist; the former consists of lanreotide Autogel (ATG) and octreotide long-acting release (LAR), and the latter refers to pegvisomant. As primary medical therapy, lanreotide ATG and octreotide LAR can be supplied in a long-lasting formulation to achieve biochemical control of GH and IGF-1 by subcutaneous injection every 4-6 weeks. Lanreotide ATG and octreotide LAR provide an effective medical treatment, whether as a primary or secondary therapy, for the treatment of GH-secreting pituitary adenoma; however, to maximize benefits with the least cost, several points should be emphasized before the application of SAs. A comprehensive assessment, especially of the observation of clinical predictors and preselection of SA treatment, should be completed in advance. A treatment process lasting at least 3 months should be implemented to achieve a long-term stable blood concentration. More satisfactory surgical outcomes for noninvasive macroadenomas treated with presurgical SA may be achieved, although controversy of such adjuvant therapy exists. Combination of SA and pegvisomant or cabergoline shows advantages in some specific cases. Thus, an individual treatment program should be established for each patient under a full evaluation of the risks and benefits.

Pharmacoeconomic aspects of the treatment of pituitary gland tumours

Nowadays physicians are under economic pressure; therefore therapeutic decisions based on safety, efficacy, and the effectiveness of the medication also require economic analysis. The aim of this review is to discuss data concerning the cost-effectiveness of drug therapy in patients with hormonally active pituitary adenomas, namely growth hormone, adrenocorticotropic hormone, thyroid-stimulating hormone-secreting pituitary adenomas, prolactinoma and pituitary incidentaloma. In acromegalic patients using lanreotide is cheaper for health care payers and more convenient for physicians and patients because of the opportunity for self/partner injections, lower clogging risk and possibility of longer intervals between injections, while the efficacy is comparable with octreotide. Patients with prolactinomas should be treated with novel dopamine agonists, such as cabergoline or quinagolide, however, bromocriptine still remains a cheaper and almost as effective alternative. There are no easy methods or algorithms, but in general, extracting the maximum value from the investment in treatment is essential.

Clinical experience with lanreotide for the treatment of acromegaly

Acromegaly is a rare disease, characterized in adults by its distinctive appearance of facial dysmorphism and swollen fingers. It is caused by an overproduction of growth hormone (GH) in more than 99% of patients and in nearly all cases is due to a pituitary adenoma. If surgical resection of the adenoma is not effective, medical treatment is usually the next treatment option. The most commonly used medications are the somatostatin analogues octreotide and lanreotide. Lanreotide is a synthetic somatostatin analogue and is available as slow-release microparticle (every 7-14 days) and prolonged-release liquid (autogel, every 28-56 days) formulations. Lanreotide autogel is a supersaturated aqueous formulation for deep subcutaneous injection and is sold in a ready-to-use prefilled syringe. This ease of use allows self or partner administration at home. This article reviews the use of lanreotide in the treatment of acromegaly and its advantages and disadvantages compared with other somatostatin analogues.

Lanreotide depot deep subcutaneous injection: a new method of delivery and its associated benefits

Acromegaly is a rare disease characterized by excessive growth hormone secretion, usually from a pituitary tumor. Treatment options include surgery, medical therapy, and in some cases, radiation therapy. Current medical therapy consists of treatment with somatostatin analog medications or a growth hormone receptor antagonist. There are two somatostatin analogs currently in use, octreotide and lanreotide. Both are supplied in long-acting formulations and are of comparable biochemical efficacy. Lanreotide is supplied in a prefilled syringe and is injected into deep subcutaneous tissue. Studies have been conducted to assess the efficacy of self- or partner administration, and have demonstrated that injection of lanreotide can be accomplished reliably and safely outside a physician's office. For patients who have achieved biochemical control with lanreotide, the FDA has recently approved an extended dosing interval. Selected patients may be able to receive the medication less frequently with injections of 120 mg administered every 6 or 8 weeks. This review focuses on the use of lanreotide in the treatment of acromegaly, the safety and efficacy of the drug, and the benefits afforded to patients because of unique aspects of the delivery of lanreotide.

Medical therapy of acromegaly in Turkey

Acromegaly is associated with multiple co-morbidities and risk of premature mortality. Mortality rate of acromegalic patients is similar to that of the general population when normal GH levels are achieved. Surgery is the mainstay of acromegaly but when surgery fails to achieve disease control, or when surgery is impossible or contraindicated, patients are offered medical therapy and/or radiotherapy. Current medical therapy modalities were revised in this short review.

New formulations and approaches in the medical treatment of acromegaly

PURPOSE OF REVIEW

To discuss novel drug formulations being developed for the medical treatment of acromegaly and to highlight recent data from studies reporting more effective therapeutic strategies using existing drugs.

RECENT FINDINGS

Despite advances in the management of acromegaly a significant number of patients remain uncontrolled. Primary medical treatment is being increasingly considered, but use of somatostatin analogues, the current mainstay of medical therapy, achieves control in only around 60% of patients, whilst 10-20% may be controlled with dopamine agonists. Consequently, improvements in drug efficacy and convenience are needed. Newer longer-acting somatostatin analogues are in development and combination regimes with the growth hormone receptor antagonist, pegvisomant, given at more cost-effective weekly doses show promising results. Somatostatin analogue-resistant tumours may respond to ligands with higher affinities to other receptors, such as pasireotide (SOM 230). Further, the combined dopamine/somatostatin receptor analogue BIM-23A760 has increased affinity to somatostatin receptors 2 and 5 and to the dopamine 2 receptor, and phase 2 clinical studies are underway.

SUMMARY

These novel drugs, formulations and treatment regimes should potentially add to the armamentarium of treatment options for patients with acromegaly.

Rapid and sustained reduction of serum growth hormone and insulin-like growth factor-1 in patients with acromegaly receiving lanreotide Autogel therapy: a randomized, placebo-controlled, multicenter study with a 52 week open extension

The study was designed to evaluate the long-term efficacy and safety of the 28-day prolonged-release Autogel formulation of the somatostatin analogue lanreotide (Lan-Autogel) in unselected patients with acromegaly. The study comprised four phases: washout; a double-blind comparison with placebo, at a single randomized dose (60, 90 or 120 mg) of Lan-Autogel; a single-blind, fixed-dose phase for four injections (placebo group was re-allocated to active treatment); and eight injections with doses tailored according to biochemical response. Serum samples were assessed for growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels, at weeks 4, 13, 14, 15, 16, 32 and 52. 108 patients were enrolled and 99 completed 52 weeks' treatment. Four weeks after the first injection, serum GH levels decreased by >50% from baseline in 63% of patients receiving Lan-Autogel compared with 0% receiving placebo (P < 0.001). After four injections, 72% of patients had a >50% reduction in GH levels; 49% patients achieved GH levels < or = 2.5 ng/ml; 54% had normalized IGF-1; and 38% achieved the combined criterion of GH level < or = 2.5 ng/ml and normalized IGF-1. The corresponding proportions by week 52 were 82, 54, 59 and 43%, respectively. In patients not requiring dose escalation to 120 mg, 85% achieved biochemical control (combined criterion). Treatment was well tolerated by all patients. In conclusion, Lan-Autogel was effective in controlling GH and IGF-1 hypersecretion in patients with acromegaly and showed a rapid onset of action.

Lanreotide for the treatment of acromegaly

Lanreotide is an eight-amino acid peptide, which is an analog of the native somatostatin peptide, physiological inhibitor of growth hormone (GH). The drug shows high binding affinity for somatostatin receptors, SSTR2 and SSTR5, which is the primary mechanism considered to be responsible for decreasing GH secretion and GH cell proliferation in acromegaly. Two different formulations of lanreotide are currently available: lanreotide slow release, which requires intramuscular injection every 7-14 days, and lanreotide autogel, which requires deep subcutaneous injection every 4-8 weeks. Several studies have been published to date on the use of lanreotide in acromegaly. Antisecretory efficacy has been reported in 35%-70% of cases; this huge variability is probably explained by different indications (eg, primary or adjunctive postsurgical treatment), or the fact that some studies were based on patients known to be responders to somatostatin analogs. As a primary treatment, antisecretory efficacy was very similar, confirming the possibility of lanreotide as an option in cases of unsuccessful surgery, contraindication, or surgery refusal. Lanreotide also has antitumoral effects as it induces a decrease in tumor volume of [Symbol: see text]25% in 30%-70% of patients. This could be beneficial before transsphenoidal surgery, as a pretreatment, to decrease tumor volume and ease surgery; however, to date, advantages in terms of final remission or uncured status remain a matter of debate. Side effects are rare; the most frequent being gastrointestinal discomfort and increased risk of gallstone formation, and glucose metabolism modifications. Comparison with the other somatostatin analog, octreotide, tends to show identical levels of efficacy between both drugs. Lanreotide thus seems to be an effective treatment in acromegaly. To date, however, lanreotide is still considered as only suspending GH secretion, thus requiring prolonged and costly treatment.

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.

A critical analysis of clinically available somatostatin analog formulations for therapy of acromegaly

CONTEXT

Short and long-acting somatostatin (SRIF) analogs are approved for clinical use in acromegaly. Recent analysis of the relative efficacy of octreotide LAR and lanreotide SR on the GH-IGF-I axis in acromegaly favored octreotide LAR in the secondary treatment of patients not preselected by SRIF responsiveness. A novel aqueous formulation of lanreotide, lanreotide Autogel (ATG), has recently been approved and is the predominant (and only in the United States) formulation of lanreotide used clinically.

OBJECTIVE

We performed a critical review of SRIF analog treatment to establish the relative efficacy of three clinically available SRIF analog preparations, octreotide LAR, lanreotide SR, and lanreotide ATG (Somatuline depot in the United States) in control of the GH-IGF-I axis in acromegaly.

DATA SOURCES

Data were drawn from MEDLINE and the bibliography of analyses of long-acting SRIF analogs.

DATA COLLECTION

We reviewed the largest studies of sc octreotide, octreotide LAR, and lanreotide SR, all that included biochemical end-point data for lanreotide ATG, and studies that directly compared the efficacy of octreotide LAR and lanreotide SR.

DATA SYNTHESIS

Caveats considered included differences in baseline GH and IGF-I values, patient selection, and interassay and intraassay variability, confounding the analysis. Studies comparing patients treated contiguously with lanreotide SR and octreotide LAR are fraught with methodological problems, however, are suggestive of marginally greater efficacy in control of the GH-IGF-I axis for octreotide LAR. Lanreotide ATG shows noninferiority to lanreotide SR. Five small studies directly comparing octreotide LAR and lanreotide ATG suggest no significant differences between these preparations in control of biochemical end-points.

CONCLUSION

Lanreotide ATG and octreotide LAR are equivalent in the control of symptoms and biochemical markers in patients with acromegaly.

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.

The role of lanreotide Autogel® in the treatment of acromegaly

Acromegaly is a rare disease, but all clinicians have to be aware of the diagnosis in order to minimize the negative consequences of increased levels of growth hormone and IGF-I, and the possible impact of a pituitary macroadenoma. Surgery remains the first-line therapy and may alleviate both hormonal excess and symptoms due to tumor mass effects. Postoperatively, however, many patients may need adjunctive therapy. Somatostatin analogs were marketed for clinical use in the 1980s. The depot formulations of the synthetic somatostatin analogs octreotide and lanreotide, octreotide acetate long-acting repeatable and lanreotide sustained release, were developed by incorporating the analogs into microspheres. The advantage of the new formulation of lanreotide, lanreotide Autogel^®, is the prefilled syringe of lanreotide and water. The choice of analog should be individualized for each patient based on level of efficacy, adverse event profile and preferred mode of administration. Approximately a third of acromegalic patients are resistant to the currently available somatostatin analogs. Monotherapy using cabergoline or pegvisomant is clinically available. Adding cabergoline to a somatostatin analog may be advantageous in selected patients and promising data exist regarding combination therapy with pegvisomant. Radiotherapy is still an option; however, although treating comorbidities and avoiding hypopituitarism is very important, radiotherapy should only be used for selected patients where treatment targets cannot be achieved by using the other therapies.

Efficacy of lanreotide Autogel administered every 4-8 weeks in patients with acromegaly previously responsive to lanreotide microparticles 30 mg: a phase III trial

OBJECTIVE AND DESIGN

Depot somatostatin analogues are well accepted as either adjuvant or primary therapy for acromegaly, and their long dosage intervals facilitate adherence to treatment. Our objective was to evaluate whether lanreotide Autogel 120 mg, every 4-8 weeks, was as effective in controlling acromegaly as lanreotide microparticles 30 mg, every 1-2 weeks. PATIENTS DESIGN AND MEASUREMENTS: Patients who had used lanreotide microparticles 30 mg, >or= 2 months prestudy, and had responded to treatment were recruited to this open, prospective, multicentre phase III trial. Three to five injections of lanreotide Autogel 120 mg were administered. Lanreotide Autogel 120 mg was injected every 4, 6 or 8 weeks in patients previously receiving lanreotide microparticles every 7, 10 or 14 days, respectively. GH and insulin-like growth factor (IGF)-1 levels were assessed one dosing interval after the final injections.

RESULTS

Ninety-eight patients were enrolled and 93 completed. Steady-state GH concentrations demonstrated similar efficacy between the formulations (upper 95% confidence interval of the quotient, 77.7%). Mean (SE) GH levels were lower with lanreotide Autogel than with lanreotide microparticles (3.8 (0.5) vs 4.3 (0.5) ng/ml; P < 0.001). GH levels < 2.5 ng/ml were observed in 54% and 46% of patients; 40% and 35% having GH < 2.5 ng/ml and normalized IGF-1 with lanreotide Autogel and microparticles, respectively. Symptoms were controlled better with lanreotide Autogel and treatment was well accepted.

CONCLUSIONS

Lanreotide Autogel 120 mg every 4-8 weeks, is at least as effective and as well tolerated in acromegaly as lanreotide microparticles 30 mg injected every 7-14 days.

Enhancing exposure of protein therapeutics

Therapeutic proteins have made a major impact on medicine, with significant expansion in the past two decades. The medicinal attributes of these agents, particularly their efficacy and often their safety profile, make protein therapeutics attractive, despite the general necessity of invasive (parenteral) delivery. This perceived hurdle has been a primary component in limiting expansion of this class of drug therapies. Strategies that reduce the frequency of administration directly provide greater convenience to the patient, and potentially greater efficacy, that can yield a significant treatment advantage.:

Pharmacokinetic profile of lanreotide Autogel in patients with acromegaly after four deep subcutaneous injections of 60, 90 or 120 mg every 28 days

OBJECTIVE

To investigate the pharmacokinetic profile of a prolonged release, aqueous Autogel formulation of the somatostatin analogue lanreotide (Lan-ATG).

DESIGN

A phase II, randomized, double-blind study, during which patients received 60, 90 or 120 mg Lan-ATG for four fixed administrations at 28-day intervals.

PATIENTS

A total of 18 patients with acromegaly were recruited; six patients were randomized to each treatment.

MEASUREMENTS

Lanreotide minimum concentration (C(min)), maximum serum concentration (C(max)) and area under the concentration-time curve during a dosing interval (AUC(tau)) were assessed after a single dose and at steady state (ss). Serum GH and IGF-1 levels were assessed before each administration and at the end of the study.

RESULTS

After a single administration, dose proportionality for C(min,1), C(max) and AUC(tau) was demonstrated statistically. After repeated administrations, Lan-ATG exhibited linear pharmacokinetics over the dose range and ss values of C(min), C(max) and AUC(tau) increased in a dose-dependent, linear manner. Mean C(max,ss) values were only two- to fourfold greater than C(min,ss) values, and there was good control over the entire release profile. Serum levels of GH and IGF-1 declined over the course of the study and acromegaly symptoms improved. The treatment was well tolerated.

CONCLUSIONS

Lan-ATG showed linear pharmacokinetic profiles over the three dose levels after both single and repeated dosing, no initial burst effect and good control over the entire release profile. Despite the absence of dose adaptation, four injections of Lan-ATG were effective in lowering serum levels of GH and IGF-1.