Efficacy of everolimus plus octreotide LAR in patients with advanced neuroendocrine tumor and carcinoid syndrome: final overall survival from the randomized, placebo-controlled phase 3 RADIANT-2 study

Background: In the phase 3 RADIANT-2 study, everolimus plus octreotide long-acting repeatable (LAR) showed improvement of 5.1 months in median progression-free survival versus placebo plus octreotide LAR among patients with advanced neuroendocrine tumors associated with carcinoid syndrome. The progression-free survival P-value was marginally above the prespecified threshold for statistical significance. Here, we report final overall survival (OS) and key safety update from RADIANT-2. Patients and methods: The RADIANT-2 trial compared everolimus (10 mg/day, orally; n = 216) versus placebo (n = 213), both in conjunction with octreotide LAR (30 mg, intramuscularly, every 28 days). Patients, unblinded at the time of progression or after end of double-blind core phase following primary analysis, were offered open-label everolimus with octreotide LAR (open-label phase). In the open-label phase, patients had similar safety and efficacy assessments as those in the core phase. For OS, hazard ratios (HRs) with 95% CIs using unadjusted Cox model and a Cox model adjusted for prespecified baseline covariates were calculated. Results: A total of 170 patients received open-label everolimus (143 crossed over from the placebo arm; 27 in the everolimus arm continued to receive the same treatment after unblinding). The median OS (95% CI) after 271 events was 29.2 months (23.8–35.9) for the everolimus arm and 35.2 months (30.0–44.7) for the placebo arm (HR, 1.17; 95% CI, 0.92–1.49). HR adjusted for baseline covariates was 1.08 (95% CI, 0.84–1.38). The most frequent drug-related grade 3 or 4 AEs reported during the open-label phase were diarrhea (5.3%), fatigue (4.7%), and stomatitis (4.1%). Deaths related to pulmonary or cardiac failure were observed more frequently in the everolimus arm. Conclusion: No significant difference in OS was observed for the everolimus plus octreotide LAR and placebo plus octreotide LAR arms of the RADIANT-2 study, even after adjusting for imbalances in the baseline covariates. Clinical Trial Number: NCT00412061, www.clinicaltrials.gov