Long-acting depot lanreotide in the treatment of patients with advanced neuroendocrine tumors.

Long-acting depot forms of somatostatin analogs administered by intramuscular injections are now available for the treatment of neuroendocrine tumors (NETs). In the present study, we investigated the efficacy and tolerability of a slow-release form of lanreotide in patients with advanced NETs. From July 1996 to January 1999, 25 patients with advanced NETs (12 carcinoids, 13 endocrine pancreatic tumors) were enrolled in the study. Thirteen patients were pretreated with subcutaneous octreotide, chemotherapy, or hepatic metastasis alcoholization. All the patients had measurable disease. Seventeen patients were symptomatic and 20 patients had elevated serum and/or urine markers. Octreotide scintigraphy was positive in 23 of 25 patients. Lanreotide was administered as intramuscular injections at the dose of 30 mg every 2 weeks until there was objective, biochemical, or symptomatic tumor progression. Objective partial responses (PRs) were documented in 2 patients (8%), whereas 10 patients (40%) had tumor stabilization. The PRs were observed in patients with midgut carcinoids, of whom one was pretreated with subcutaneous octreotide. The response duration was 21+ and 24+ months in responding patients; the median duration of disease stabilization was 8.5 months (range, 4-21+). The overall biochemical response rate was 42%, including 2 complete responses (CRs) (10.5%) and 6 PRs (31.5%); all biochemical responses were observed mostly in patients with carcinoid tumors; the duration of response was 18+ and 30+ months for CRs; the median duration of biochemical response was 7 months (range, 4-18+) for PRs. The overall symptomatic response rate was 70% with a median duration of 7.5, 18, and 18+ months for diarrhea, abdominal pain, and flushing, respectively. Median duration of lanreotide treatment was 10 months (range, 2-30+). No significant side effects were reported. Depot lanreotide 30 mg shows significant efficacy in terms of objective response rate and in biochemical and symptomatic control, in pretreated patients as well as nonpretreated patients with advanced NETs. Tolerability is good, with good patient compliance.