Long‐term safety and efficacy of lanreotide autogel in Japanese patients with neuroendocrine tumors: Final results of a phase II open‐label extension study

Aim The aim of this study was to describe the long‐term safety and efficacy of lanreotide in Japanese patients with neuroendocrine tumors. Methods The final analyses of a 48‐week open‐label phase II study (n = 32) and its extension study (n = 17) were conducted. Patients received 4‐weekly subcutaneous injections of lanreotide autogel 120 mg. Safety was evaluated by adverse events. Efficacy endpoints included tumor response by RECIST and change in tumor size. Post hoc analyses including tumor growth rate were performed. Results The median (range) of lanreotide exposure in the safety analysis set (n = 17) and efficacy analysis set (n = 28) were 151.4 (52–181) and 52.7 (12–181) weeks, respectively. Sixteen patients developed adverse drug reaction; of these, upper abdominal pain and urticaria were not reported before 48 weeks. No patient discontinued lanreotide or died from an adverse event. Two serious events of bile duct stones in one patient were drug‐related. Partial response was observed in 2 patients (7.1%; at 60 and 108 weeks), stable disease in 20 (71.4%) and progressive disease in 6 (21.4%). The mean of the greatest change from baseline in the sum of diameters of target lesions was −5.5%. The mean (standard deviation) tumor growth rate before treatment and from baseline to last observation was 25.3% (35.7%)/month and 6.4% (9.6%)/month, respectively. Conclusion Lanreotide treatment had an acceptable safety profile and was effective over long‐term treatment in Japanese patients with neuroendocrine tumors. No unexpected serious adverse events developed during prolonged use of lanreotide.