A Study of Nasal PYY3-36 and Placebo for Weight Loss in Obese Subjects

This is a multi-center, Phase 2 double-blind, randomized, placebo-controlled trial in healthy obese patients. The primary objective of the study is to evaluate the effect of increasing nasal PYY3-36 dosing on weight loss post 24 weeks of treatment. Secondary Objectives: * To evaluate the safety of three nasal PYY3 36 dose groups compared to nasal placebo * To compare the weight loss post 12 and 24 weeks of treatment for each of the three nasal PYY3 36 dose groups versus the nasal placebo group * To compare the proportion of patients who lose at least 5% and 10% of the baseline body weight post 12 and 24 weeks of therapy for each of the three nasal PYY3 36 dose groups versus the nasal placebo group * To compare the weight loss and proportion of patients who lose at least 5% of the baseline body weight post 12 and 24 weeks of treatment with sibutramine versus capsule placebo * To compare the weight loss and proportion of patients who lose at least 5% of the baseline body weight post 12 and 24 weeks of treatment with nasal placebo versus capsule placebo * To compare the weight loss and proportion of patients who lose at least 5% of the baseline body weight post 12 and 24 weeks of treatment with sibutramine versus the nasal PYY3 36 dose groups * To evaluate the effect of 12 and 24 weeks of treatment with nasal PYY3 36 and sibutramine on fasting lipid profile, plasma glucose, insulin, blood pressure and pulse, waist circumference and BMI * To evaluate the effect of 24 weeks of treatment with nasal PYY3 36 and sibutramine on HbA1c levels