Multiple pathways including peripheral and central hormones and neurotransmitters are involved in the regulation of food intake and body weight. One of the most studied pathways involves the melanocortin receptor. Agouti-related protein (AgRP) and alpha-melanocyte stimulating hormone (alphaMSH)have been shown to play an integral role in food intake and body weight.

It is reasonable to speculate that if there is an imbalance of alphaMSH and AgRP exist in obese individuals and inhibiting the activity of AgRP may be of therapeutic benefit in treating obesity.

Inclusion Criteria:

• Male or female volunteers, aged 18 to 65 years, inclusive.
• Subjects must be obese (class 1: BMI of 30.0 to 34.9 kg/m2 or class 2: BMI of 35 to 39.9 kg/m2 in non-Asians and BMI of 27.0 - 31.9 kg/m2 or 32.0 - 36.9 kg/m2 in Asians) at the Screening Visit.
• Female subjects must be postmenopausal (with amenorrhea for at least 2 years prior to scheduled dosing and confirmatory FSH test in the range of 23-116 IU/L) or surgically sterile (with physician or insurance documentation of bilateral tubal ligation at least 6 months prior to Screening Visit or of a hysterectomy and/or bilateral oophorectomy) and agree not to undergo in vitro fertilization during the study and for 6 months post treatment.

Exclusion Criteria:

• Type 1 diabetes.
• Type 2 diabetes.
• History of myocardial infarction, stroke, including transient ischemic attack, in the last 2 years.
• Asthma or chronic obstructive pulmonary disease controlled by regular use of inhaled steroids.
• Subjects with rheumatoid arthritis, lupus, or multiple sclerosis regularly requiring steroids or disease-modifying anti-rheumatic agents.
• Subjects with psoriasis requiring oral steroids.
• Subjects planning to undergo gastric bypass or resection surgery, or who have had such a procedure in the 6 months prior to the Screening Visit.