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NEW YORK, NY MAY 16 - Manhattan Pharmaceuticals, Inc. (AMEX: MHA) today reported receipt of Swiss regulatory approval to commence its Phase IIa study with oral Oleoyl-estrone (OE), the company's drug candidate for the treatment of obesity.

The single center, Phase IIa study is a randomized, double-blind, placebo-controlled, parallel group study designed to evaluate the safety, preliminary efficacy, and pharmacokinetics of two 14-day dosing cycles in obese adult subjects. 100 subjects will be randomly enrolled in one of four treatment groups. Dose levels of OE will be placebo, 5, 10, or 20 mg taken once daily. Each 14-day dosing cycle will be followed by a 28-day treatment free evaluation period.

"This approval marks a significant achievement in the clinical development program with oral Oleoyl-estrone," said Douglas Abel, Manhattan's CEO. "Given the encouraging early trial results and the large unmet medical need in obesity, we are very pleased to be able to proceed toward patient recruitment and enrollment."

"Oleoyl-estrone is a promising drug candidate and is thought to work both centrally and peripherally," said Alan G. Harris, MD, PhD, Manhattan's chief medical officer. "Centrally, it appears to reset the body's ponderostat, the 'food control center' located in the hypothalamus of the brain that detects and integrates signals controlling appetite and metabolic behavior. Peripherally, OE appears to cause reduced storage of fat in 'white fat' tissue and allows skeletal muscle to use fat as an alternate energy source."

OE is an orally administered, synthetic form of Oleoyl-estrone, a molecule that exists naturally in the body. Results of the Phase I clinical trials with OE, reported in October 2005, showed the compound was well tolerated. Subjects in the Phase Ib study experienced weight loss as well as beneficial changes in blood glucose and cholesterol levels. There was also evidence of OE offering the potential for sustained weight loss after dosing with OE stopped. Clinical laboratory findings included reversible, dose-dependent elevations in estrone and estradiol levels, as well as reductions in testosterone levels.

Obesity is rapidly becoming a global epidemic. The US Centers for Disease Control reports that 65 percent of Americans are overweight and 30 percent are obese. The number of clinically obese Americans is expected to grow from 73 million 94 million during the next 5-6 years. Currently marketed obesity treatments have not been shown to be particularly effective in accomplishing sustained weight loss. Even if weight loss is achieved, current obesity treatments do not reduce the likelihood of regain of lost weight once treatment has stopped. Most marketed weight loss therapeutics also cause unwanted side effects.

About Manhattan Pharmaceuticals, Inc.
Manhattan Pharmaceuticals, Inc., a development-stage pharmaceutical company, acquires and develops proprietary prescription drugs for large, underserved patient populations. In view of the worldwide obesity epidemic, the company is developing OE, an orally administered novel therapeutic for the treatment of obesity. To meet the needs of other major, underserved medical markets while lowering development risks, Manhattan Pharmaceuticals is also developing PTH (1-34), a peptide believed to be a regulator of epidermal cell growth, for psoriasis, and Propofol Lingual Spray, a convenient, proprietary lingual spray formulation of propofol, the world's best-selling general anesthetic, as a sedative-hypnotic for use during diagnostic and therapeutic procedures. (http://www.manhattanpharma.com)