Effectiveness and tolerability of slow release lanreotide treatment in active acromegaly: six-month report on an Italian multicenter study. Italian Multicenter Slow Release Lanreotide Study Group

Paltusotine, a novel oral once-daily nonpeptide SST2 receptor agonist, suppresses GH and IGF-1 in healthy volunteers

PURPOSE

Evaluate the pharmacodynamics, pharmacokinetics, and safety of paltusotine, an orally bioavailable, nonpeptide, somatostatin receptor subtype 2 (SST2) agonist being developed for the treatment of acromegaly and neuroendocrine tumors.

METHODS

A randomized, double-blind, placebo-controlled, single center, single and multiple ascending dose phase 1 study was conducted in healthy male volunteers who received (i) single-dose of oral paltusotine 1.25, 2.5, 5, 10, and 20 mg (solution); and 40 and 60 mg (capsules) or (ii) multiple-dose oral paltusotine capsules once daily 5 mg (× 7 days), 10, 20, and 30 mg (× 10 days). Main outcome measures were pharmacodynamics (changes in growth hormone-releasing hormone [GHRH] stimulated growth hormone [GH] and insulin-like growth factor 1 [IGF-1]), pharmacokinetics, safety, and tolerability.

RESULTS

Single-dose cohorts: n = 41 active, n = 14 placebo. Multiple-dose cohorts: n = 24 active, n = 12 placebo. Paltusotine was well tolerated, orally bioavailable, associated with increased plasma concentrations to doses up to 40 mg, and was eliminated with a half-life of approximately 30 h. Single-dose paltusotine 1.25 to 20 mg suppressed GHRH-stimulated GH secretion by 44% to 93% compared to 15% with placebo. Multiple-dose paltusotine 5 to 30 mg administered once daily for 10 days suppressed IGF-1 by 19% to 37% compared to an increase of 2.4% with placebo.

CONCLUSIONS

Paltusotine suppresses GH and IGF-1 in a dose-dependent fashion, with a safety profile similar to currently approved SST2 receptor ligands. Paltusotine is a promising once-daily oral nonpeptide SST2 agonist candidate for managing acromegaly and neuroendocrine tumors.

TRIAL REGISTRATION

NCT03276858, registered September 8, 2017, retrospectively registered.

Desensitization treatment for hypersensitivity reaction to octreotide in an acromegalic patient

Octreotide is widely used as medical therapy for acromegaly. It is known to markedly reduce growth hormone levels, improve symptoms and reduce tumor size. Common side effects include gastrointestinal symptoms, hepatobiliary disorders, dizziness, headaches, bradycardia, hyperglycemia or hypoglycemia and thyroid dysfunction. Although urticaria, allergy/hypersensitivity reactions and anaphylaxis have been noted as possible adverse reactions, there is a lack of data showing a causal relationship between octreotide and hypersensitivity reactions and there is no information on management when continued use of this medication is essential. We now report a case of a 60 year old male with acromegaly who had presented with a cutaneous hypersensitivity reaction to octreotide. In addition he failed treatment with surgery, radiation, and dopamine agonist and could no longer afford to continue treatment with pegvisomant. The patient underwent desensitization treatment for his octreotide allergy and was able to resume treatment without any further side effects. We believe this case represents the first report of successful desensitization treatment for octreotide allergy in an acromegalic patient.

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.

Acromegaly

Acromegaly is caused by growth hormone hypersecretion, mostly from a pituitary adenoma, driving insulin-like growth factor 1 overproduction. Manifestations include skeletal and soft tissue growth and deformities; and cardiac, respiratory, neuromuscular, endocrine, and metabolic complications. Increased morbidity and mortality require early and tight disease control. Surgery is the treatment of choice for microadenomas and well-defined intrasellar macroadenomas. Complete resection of large and invasive macroadenomas rarely is achieved; hence, their low rate of disease remission. Pharmacologic treatments, including long-acting somatostatin analogs, dopamine agonists, and growth hormone receptor antagonists, have assumed more importance in achieving biochemical and symptomatic disease control.

Acromegaly: historical perspectives and current therapy

Soon after the initial description of acromegaly in the late 19th century, neurosurgeons performed the first operative procedures for the disease. Transcranial procedures eventually yielded to the transsphenoidal approach. Reasonably effective medical therapy was introduced in the 1970s and pharmacological progress continues to be realized. It is now recognized that excess growth hormone is associated with significant morbidity and mortality and that biochemical remission improves outcome. Although medical and radiation treatments offer useful adjuncts, surgery provides optimal results.

Lanreotide 60 mg, a longer-acting somatostatin analog: tumor shrinkage and hormonal normalization in acromegaly

BACKGROUND

Somatostatin analogues are nowadays the milestone in the medical treatment of acromegaly. We evaluated the effects of a new 60 mg longer-acting formulation of lanreotide (LAN60) on GH/IGF-I levels and tumor size.

PATIENTS

Twenty-one acromegalics entered a prospective monocentric open study. Eight were consecutive "de novo" patients (group I). Thirteen patients sensitive to SA (GH levels < 2.5 [mgr]g/l and/or IGF-I normalization on chronic LAN 30 mg (LAN30) treatment) were switched to LAN60 (group II).

PROTOCOL

LAN60 was administered IM for 6 cycles at 28 day intervals. In group I when GH/IGF-I remained pathological, the intervals were shortened to 21 days for the last three cycles.

CONTROLS

GH/IGF-I at the end of the 1st, 3rd and 6th cycle; MRI at the end of the study in all patients in group I bearing an adenoma.

RESULTS

Group I. GH (p = 0.00638, below 2.5 [mgr]g/l in two patients) and IGF-I (p = 0.0289, normalized in 5) significantly decreased. In one of two patients shortening the LAN60 schedule was more effective in suppressing GH/IGF-I. Group II. No change in GH and IGF-I levels was observed with the administration of LAN60, instead of LAN30. On LAN60 GH remained below 2.5 [mgr]g/l in 8/10 patients and IGF-I normal in 11/11 patients that had attained those values on LAN30. Tumor markedly shrank (23% to 64% vs basal), from 1400 (664-1680) mm3 to 520 (500-960) mm3 (median, interquartile, p = 0.0218) in all the 5 evaluable patients.

CONCLUSION

LAN60 is a very effective and longer-lasting formulation for the treatment of acromegaly. A closer administration schedule might achieve greater efficacy. Its effectiveness in shrinking tumor opens new perspectives in the therapy of acromegaly.

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

OBJECTIVE

To determine the effects of the new somatostatin analogue, lanreotide, in its prolonged released form (PR), in patients with acromegaly.

DESIGN

Prospective open multicenter non comparative study.

SETTING

Thirty-three university-affiliated medical centers.

PATIENTS

One hundred sixteen acromegalic patients with active disease, of whom 58 patients complied with the protocol and completed the 12-month period treatment.

INTERVENTION

Lanreotide PR treatment was started at a dose of 30 mg intramuscularly every 14 days. If integrated mean plasma GH levels were not below 5 micrograms/L and/or IGF-I levels were not normalized after one month of treatment, injections were given every 10 days. The duration of the study was 12 months.

RESULTS

After one month of treatment mean plasma GH and IGF-I levels had fallen from 10.7 +/- 11.1 micrograms/L (mean +/- SD; range, 2.6-74.8 micrograms/L; median, 7 micrograms/L) and 718 +/- 270 micrograms/L (range 338-1440 micrograms/L; median, 645 micrograms/L), respectively, to 7.8 +/- 10.1 micrograms/L and 575 +/- 252 micrograms/L, respectively. Thirty patients (22%) had plasma GH levels below 2.5 micrograms/L, and 8 patients (16%) had age-adjusted normal plasma IGF-I levels. At the sixth month of treatment mean plasma GH levels of 2.5 micrograms/L or less, and normal plasma IGF-I levels were observed in 33%, and 33% of patients, respectively. At the twelvth month of treatment, these percentages were 41%, and 41%, respectively. The interval between two injections was shortened (one injection every 10 days) in 8 of the 58 patients (13%) at the second month of treatment, and at the end of the study, 70% of patients required 3 injections per month. The most frequent adverse event elicited by enquiry was transient diarrhea (76% of patients), followed by abdominal pain (62%) and pain at the injection site (59%). Based on the analysis of a subgroup of 46 patients who had at least a measurement of fecal fat content after day 0 of the study, a non significant increase (from 4.2 +/- 3.4 to 5.1 +/- 4.3 g/24 h, p = 0.3) in mean steatorrhea was observed during treatment. Before treatment, steatorrhea was present in 9 (19%) patients. During the study, 15 additional patients (32%) developed persistent steatorrhea, and there was a transient increase in fecal fat content above 6 g/24 h in another 11 patients. After exclusion of the 7 patients (12%) with gallstones at enrollment, new gall-stones were diagnosed in 6 out of 50 patients (12%) during the study.

CONCLUSION

Two or three monthly injections of lanreotide PR decreased GH concentration to less than 2.5 micrograms/L and normalized IGF-I levels in 41% of patients treated during 12 months. The good tolerability of this treatment, and the reduction in the frequency of injections, plus the sustained drug serum concentrations, confirm the usefulness of this new somatostatin analog formulation.

Efficacy of combined treatment with lanreotide and cabergoline in selected therapy-resistant acromegalic patients

The aim of this study was to evaluate the efficacy of a 6-month treatment with lanreotide (LAN) (60-90 mg/month) alone and combined with cabergoline (CAB) (1.5-3 mg/week) in 10 acromegalic patients previously demonstrated to be poor responders to octreotide (OCT) (0.6 mg/day) alone and combined with quinagolide (CV) (0.6 mg/day). All patients had previously undergone unsuccessful surgery and none of them received radiotherapy. Immunohistochemistry showed intense positive GH staining in all adenomas, positive PRL staining in 5 adenomas and faint ACTH or FSH/LH positive staining in other 2 adenomas. Moderately elevated serum PRL levels (35 and 47 ng/ml) were recorded in two patients. Fasting plasma IGF-I and serum GH levels were assayed at baseline and 30, 60, 90 and 120 days after each treatment. Gallbladder ultrasonography and sellar MRI were performed before and after 6 months of OCT and LAN treatments. After OCT treatment circulating GH and IGF-I levels remained elevated in all patients, while after 3 months of combined OCT + CV treatment, serum GH levels were suppressed (below 2.5 ng/ml) in only 1 patient. Significant increase of the percent GH (83.9 +/- 4.3 vs. 70.3 +/- 5.6%, p < 0.01) and IGF-I suppression (54 +/- 4.4 vs. 45.3 +/- 5.7, p < 0.01) and decrease of the nadir of GH (8.5 +/- 1.2 vs. 14.6 +/- 1.9 ng/ml, p < 0.01) and IGF-I (400.9 +/- 32.8 vs. 462.1 +/- 45.1 ng/ml) were obtained with the combined treatment when compared to OCT treatment alone. After a 15-30 days wash-out, circulating GH and IGF-I levels significantly increased up to pretreatment level in all patients. After 6 months of treatment with LAN, suppression of serum GH was achieved in 1 patient, but no difference in GH (66.3 +/- 6.3%) and IGF-I (43.9 +/- 4.6%) suppression was recorded in comparison to OCT treatment. After 3 months of treatment with LAN combined with CAB, suppression of serum GH and normalization of plasma IGF-I levels was achieved in 4 and 5 patients, respectively. Percent suppression of GH (88.1 +/- 2.1%) and IGF-I (57.5 +/- 2.8%) was significantly greater with the combined treatment than with LAN treatment alone. In the 7 patients with evident residual mass no change was documented by magnetic resonance imaging (MRI). None of the patients withdrew LAN + CAB treatment for poor tolerance, one patient had mild hypotension. Sludge was shown after 6 months of LAN treatment in one patient without notable change after 3 months of LAN + CAB treatment. In conclusion, the treatment with dopaminergic drugs such as CV and CAB, significantly increased the efficacy of somatostatin analogs, and can be used in combined therapy in poorly responsive patients.