Octreotide acetate long-acting formulation versus open-label subcutaneous octreotide acetate in malignant carcinoid syndrome

Purpose: Subcutaneous (SC) octreotide acetate effectively relieves the diar rhea and flushing associated with carcinoid syndrome but requires long-term multiple injections daily. A microencapsulated long-acting formulation (LA R) of octreotide acetate has been developed for once-monthly intramuscular dosing. Patients and Methods: A randomized trial compared double-blinded octreotide LAR at 10, 20, and 30 mg every 4 weeks with open-label SC octreotide every 8 hours for the treatment of carcinoid syndrome. Seventy-nine patients con trolled with treatment of SC octreotide 0.3 to 0.9 mg/d whose symptoms retu rned during a washout period and who returned for at least the week 20 eval uation constituted the efficacy-assessable population. Results: Complete or partial treatment success was comparable in each of th e four arms of the study (SC, 58.3%; 10 mg, 66.7%; 20 mg, 71.4%; 30 mg, 61. 9%; P greater than or equal to .72 for all pairwise comparisons). Control o f stool frequency was similar in all treatment groups. Flushing episodes we re best controlled in the 20-mg LAR and SC groups; the 10-mg LAR treatment was least effective in the control of flushing, Treatment was well tolerate d by patients in all four groups. Conclusion: Once octreotide steady state concentrations are achieved, octre otide LAR controls the symptoms of carcinoid syndrome at least as well as S C octreotide. A starting dose of 20 mg of octreotide LAR is recommended. Su pplemental SC octreotide is needed for approximately 2 weeks after initiati on of octreotide LAR treatment. Occasional rescue SC injections may be requ ired for possibly 2 to 3 months until steady-state octreotide levels from t he LAR formulation are achieved. (C) 1999 by American Society of Clinical O ncology.