Endocrine Abstracts

Introduction: Somatostatin analogues (SSAs) are the mainstay treatment for carcinoid syndrome. ELECT is a large multinational phase 3 study evaluating rescue therapy use as a measure for control of carcinoid syndrome symptoms with LAN-ATG.

Methods: Eligible patients had histologically-confirmed GEP-NETs and history of carcinoid syndrome, and were SSA-naïve or responsive to conventional doses of octreotide LAR (≤30 mg/4 weeks) or short-acting (≤600 μg/day s.c.). The study comprised a 16-week randomized double-blind phase (LAN-ATG 120 mg (n=59) vs placebo (n=56) every 4 weeks), followed by a 32-week long-term open-label phase on LAN-ATG. Short-acting octreotide was available as rescue for breakthrough symptoms throughout the study. Primary endpoint was % of days of rescue octreotide use during the double-blind phase. The study was designed to have 90% power to detect a treatment difference of 30%. Results of the double-blind phase only are presented (open-label phase still ongoing).

Results: Of the study population, 83 (72%) had symptoms for ≥1 year, and 51 (44%) had no prior SSA use. Mean (95% CI) % of days with rescue medication use was significantly lower with LAN-ATG (34% (25, 42%)) vs placebo (49% (40, 57%)), absolute difference −15% (−27, −3%), P=0.02; however, the pre-defined difference was not met. Complete/partial success (≤3 days use) rather than failure (>3 days use) was more likely with LAN-ATG than placebo (OR 2.4; 95% CI 1.1–5.3; P=0.04). Treatment related AEs occurred in 15 (26%) LAN-ATG patients vs 11 (19%) placebo patients; Few of these were serious (2 (3%) vs 5 (9%)) or led to study withdrawal (1 (2%) vs 1 (2%)); and were most commonly GI disorders (9 (16%) vs 5 (9%)).

Conclusions: LAN-ATG significantly reduced need for short-acting SSA use and had a favourable safety/tolerability profile confirming its positive benefit-risk profile.