Multiple once-daily subcutaneous doses of pasireotide were well tolerated in healthy male volunteers: a randomized, double-blind, placebo-controlled, cross-over, Phase I study

A randomized, double-blind, placebo-controlled, cross-over, dose-escalating, single-center study was conducted to evaluate the safety, tolerability, and pharmacokinetic (PK) profile of multiple once-daily (qd) subcutaneous (sc) doses of pasireotide in healthy male subjects. Subjects received pasireotide 50, 200, or 600 μg sc qd for 14 days and placebo in separate sequences. Thirty-three subjects were randomized. The most frequently reported drug-related adverse events were injection-site reactions (n = 18), diarrhea (n = 14) and nausea (n = 10), which were mostly mild or moderate in intensity. Pasireotide 600 μg sc was associated with pre- and post-prandial elevations in glucose levels relative to placebo; however, this effect was less pronounced on day 14 compared with day 1. PK steady state appeared to be achieved after 3 days of dosing and PK exposures had a moderate accumulation of 20-40 % across doses. Pasireotide demonstrated fast absorption (T(max,ss): 0.25-0.5 h), low clearance (CL/F(ss): 8.10-9.03 L/h), long effective half-life (T(½,eff): ~12 h, on average between 9.7 and 13.1 h for 50, 200, and 600 μg sc qd), and large volume of distribution (V(z)/F(ss): 251-1,091 L) at steady state. Dose proportionality was confirmed for C(max,ss); other PK parameters (C(max), AUC(0-24 h) and AUC(tau)) were approximately dose proportional. Growth hormone inhibition was observed with pasireotide 200 and 600 μg sc qd. Gallbladder volume increased post-prandially with pasireotide 200 and 600 μg sc qd, which appeared to correlate with reduced levels of cholecystokinin at these doses. Pasireotide was generally well tolerated up to the tested dose of 600 μg qd, with a linear and time-independent PK profile after sc qd dosing in healthy subjects.

Treatment options for unresectable neuroendocrine liver metastases

Hepatic metastases develop in 85% of patients with gastroenteropancreatic neuroendocrine tumors. Radical surgery, which involves resection of the primary and liver metastases, is the mainstay of treatment, with 60-70% 5-year survival and 35% 10-year survival rates. However, less than 15% of neuroendocrine tumor liver metastases (NETLMs) are resectable, owing either to multifocality or the inability to preserve sufficient parenchyma following resection. This article deals with the therapeutic modalities available for nonresectable liver metastases, and the therapeutic options available for management of nonresectable NETLMs are discussed. Targeted therapies for NETLMs include hepatic artery embolization, transcatheter arterial chemoembolization, radiolabeled/drug-eluting microspheres, radiofrequency ablation, cryoablation and phenol injection. Hepatic artery embolization/transcatheter arterial chemoembolization is associated with 75-100% symptom relief and an objective tumor response varying from 33 to 80%. Other modalities, such as biotherapy, peptide receptor therapy and chemotherapy, target both the primary and metastatic disease. Their effects on NETLMs as a subgroup have not been evaluated. Various therapeutic options are available for the treatment of unresectable NETLMs. Most offer significant symptomatic relief, with only a few comparative studies showing survival benefit. Most of the available evidence is based on retrospective and prospective case series rather than randomized controlled trials. Well-designed studies on existing treatment modalities and the search for newer therapeutic options are required.

Therapeutic management of patients with gastroenteropancreatic neuroendocrine tumours

Patients with neuroendocrine tumours (NETs) are best managed in a specialist centre as part of a multidisciplinary team comprising gastroenterologists, oncologists, endocrinologists, gastrointestinal and hepatopancreaticobiliary surgeons, pathologists, nuclear medicine physicians and technicians, radiologists, specialist nurses, pharmacists, biochemists and dieticians. This should ideally be led by a clinician with experience and interest in NETs. Although the number of medical treatments and clinical trials has increased in the decade, there is still a lack of prospective randomised trials; thus, management is mainly based on limited often single-centre studies, although there are now formal guidelines based on consensus expert opinion. We have outlined the current optimal management of patients with NETs. We have reviewed therapeutic options including surgery, somatostatin analogues and other biotherapies and peptide receptor-targeted therapy. We have discussed the challenge in managing hepatic metastases including hepatic artery embolisation, ablation and orthotopic liver transplant. In addition, we have briefly reviewed the emerging therapies such as the mammalian target of rapamycin and angiogenic inhibitors and the newer somatostatin analogues.

Review article: future therapies for management of metastatic gastroenteropancreatic neuroendocrine tumours

BACKGROUND

Gastroenteropancreatic neuroendocrine tumours (GEP NETs) are relatively uncommon tumours that occur anywhere within the gastrointestinal tract. The prevalence of GEP NETs is estimated to be 35 per 100 000 population. Patients often present with metastatic disease and consequently, palliative treatments form the mainstay of therapy.

AIM

To review the current and novel therapeutic options for management of GEP NETs.

METHODS

Searches for all studies related to GEP NETs, NETs and carcinoid tumours in Medline and abstracts from international meetings.

RESULTS

Somatostatin analogues remain the first line therapy for management of symptoms of GEP NETs and may have anti-proliferative action. New somatostatin analogues with different somatostatin receptor affinity have been developed. Radionuclide peptide receptor therapy is established in patients with positive somatostatin scintigraphy. A number of new agents and targeted therapies are currently being evaluated in a phase I and II studies and these include angiogenic inhibitors, mammalian target of rapamycin inhibitors and immune therapies.

CONCLUSIONS

A number of nonsurgical therapies are available for management of gastroenteropancreatic neuroendocrine tumours. It is hoped, the development of some of these promising novel therapies will expand the therapeutic armamentarium.