OREXIGEN™ Therapeutics Announces Notice of Allowance for U.S. Patent Extending Exclusivity for Composition of Contrave™ to 2024

Business Wire, Jan 31, 2008

SAN DIEGO -- Orexigen(TM) Therapeutics, Inc. (Nasdaq: OREX), a biopharmaceutical company focused on the treatment of central nervous system disorders, including obesity, today announced that a Notice of Allowance has been electronically posted by the United States Patent and Trademark Office (USPTO) for a patent application covering sustained release (SR) compositions of bupropion and naltrexone combined in a single dosage form. These two drugs are the active constituents in Contrave[TM], Orexigen's lead product candidate for the treatment of obesity, now in Phase III clinical trials. Referred to by the Company as the Weber/Cowley composition patent application, this patent would provide protection for Contrave into the year 2024. This development is an important milestone toward issuance of the patent by the USPTO. Issuance of this patent by the USPTO would extend the Company's exclusive rights on this combination in the United States for an additional 11 years beyond its current patent protection.

"This patent, upon issuance, would further strengthen the intellectual property position for this novel, proprietary drug combination," said Orexigen President and CEO, Gary Tollefson, M.D., Ph.D. "As a composition-of-matter patent it would cover all uses and doses of Contrave into 2024."

Contrave is a proprietary fixed dose combination of bupropion SR and the Company's novel formulation of naltrexone SR in a single tablet. Orexigen chose these two constituent drugs based on preclinical data that suggested that they could both initiate and sustain weight loss. The Contrave Phase IIb clinical trial at 48 weeks demonstrated weight loss from baseline body weight that ranged from 8.0% to 10.7% across the three Contrave dosage groups among patients who completed the trial. The Phase III clinical trials of Contrave are expected to be completed by mid-2009 with the filing of a New Drug Application (NDA) with the FDA projected for late 2009.

About Orexigen Therapeutics

Orexigen(TM) Therapeutics, Inc. is a biopharmaceutical company focused on the development of pharmaceutical product candidates for the treatment of central nervous system disorders, including obesity. Orexigen's lead combination product candidates targeted for obesity are Contrave[TM], which is in Phase III clinical trials, and Empatic[TM], which is in the later stages of Phase II clinical development.

Forward-Looking Statements

Orexigen cautions you that statements included in this press release that are not a description of historical facts are forward-looking statements. Words such as "believes," "anticipates," "plans," "expects," "indicates," "will," "intends," "potential," "suggests," "assuming," "designed" and similar expressions are intended to identify forward-looking statements. These statements are based on Orexigen's current beliefs and expectations. These forward-looking statements include statements regarding the issuance of a patent covering SR compositions of buproprion and naltrexone combined in a single dosage form, the timing of the completion of the Company's Contrave Phase III clinical trials and the timing of its submission of an NDA with the FDA. The inclusion of forward-looking statements should not be regarded as a representation by Orexigen that any of its plans will be achieved. Actual results may differ from those set forth in this release due to the risk and uncertainties inherent in Orexigen's business, including, without limitation: the progress and timing of the Company's Contrave clinical trials or the development of Contrave; the potential for adverse safety findings relating to Contrave to delay or prevent regulatory filings; and its licensors may not be able to obtain, maintain and successfully enforce adequate patent and other intellectual property protection of its product candidates; and other risks described in Orexigen's filings with the Securities and Exchange Commission (SEC). You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and Orexigen undertakes no obligation to revise or update this news release to reflect events or circumstances after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement. This caution is made under the safe harbor provisions of Section 21E of the Private Securities Litigation Reform Act of 1995.