Impax Pharmaceuticals, the branded products division of Impax Laboratories, Inc. (NASDAQ: IPXL), announced that it has initiated a Phase IIb trial of its drug candidate IPX159 in patients with moderate to severe Restless Legs Syndrome (RLS).

“We are pleased to advance IPX159 to this Phase IIb study, which will help establish its clinical profile in moderate to severe RLS patients. We look forward to reporting the results from this study and providing an update on the program in mid-2013,” said Suneel Gupta, Ph.D., chief scientific officer, Impax Pharmaceuticals.

The Phase IIb study is a multicenter, randomized, double-blind, placebo-controlled, safety and efficacy study to evaluate IPX159 in the treatment of moderate to severe RLS. The trial is expected to randomize approximately 120 adult subjects who will receive either IPX159 or placebo and will be treated for up to 11 weeks. The trial will be conducted at multiple sites in North America. The primary endpoint is the International Restless Legs Syndrome Study Group (IRLSSG) Rating Scale.

About IPX159

IPX159 is an oral controlled-release formulation of a small molecule that has an established pharmacological and safety profile for non-RLS use outside the U.S. and may represent a novel mechanism of action in RLS. Impax has previously completed a proof of concept study with the molecule in RLS patients.

About Restless Legs Syndrome

Restless Legs Syndrome (RLS) is a condition characterized by an irresistible urge to move ones’ limbs, most commonly the legs, to stop uncomfortable sensations. RLS symptoms generally worsen in the evening, are made worse by rest or inactivity, and commonly cause insomnia and involuntary leg movements during sleep. There are approximately 25 million RLS sufferers in the US.

About Impax Laboratories, Inc.

Impax Laboratories, Inc. is a technology-based specialty pharmaceutical company applying its formulation expertise and drug delivery technology to the development of controlled-release and specialty generics in addition to the development of branded products. Impax markets its generic products through its Global Pharmaceuticals division and markets its branded products through the Impax Pharmaceuticals division. Additionally, where strategically appropriate, Impax has developed marketing partnerships to fully leverage its technology platform. Impax is headquartered in Hayward, California, with a full range of capabilities located in its Hayward, Philadelphia and Taiwan facilities. For more information, please visit the Company's Web site at: www.impaxlabs.com.

" Safe Harbor" statement under the Private Securities Litigation Reform Act of 1995:

To the extent any statements made in this news release contain information that is not historical, including the statements under the heading “2011 Financial Outlook,” these statements are forward-looking in nature and express the beliefs and expectations of management. Such statements are based on current expectations and involve a number of known and unknown risks and uncertainties that could cause the Company’s future results, performance or achievements to differ significantly from the results, performance or achievements expressed or implied by such forward-looking statements. Such risks and uncertainties include, but are not limited to, the effect of current economic conditions on the Company’s industry, business, financial position and results of operations, the ability to maintain an effective system of internal control over financial reporting, fluctuations in revenues and operating income, the ability to successfully develop and commercialize pharmaceutical products, reductions or loss of business with any significant customer or a reduction in sales of any significant product, the impact of competition, the ability to sustain profitability and positive cash flows, any delays or unanticipated expenses in connection with the operation of the Taiwan facility, the effect of foreign economic, political, legal and other risks on operations abroad, the uncertainty of patent litigation, consumer acceptance and demand for new pharmaceutical products, the difficulty of predicting Food and Drug Administration filings and approvals, the inexperience of the Company in conducting clinical trials and submitting new drug applications, the ability to successfully conduct clinical trials, reliance on alliance and collaboration agreements, the availability of raw materials, the ability to comply with legal and regulatory requirements governing the pharmaceuticals and healthcare industries, the regulatory environment, the ability to protect the Company’s intellectual property, exposure to product liability claims and other risks described in the Company’s periodic reports filed with the Securities and Exchange Commission. Forward-looking statements speak only as to the date on which they are made, and Impax undertakes no obligation to update publicly or revise any forward-looking statement, regardless of whether new information becomes available, future developments occur or otherwise.

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