Exhibit 99.1

For Immediate Release

Cephalon Reported Strong Financial Results

For The First Quarter Of 2011

First Quarter 2011 Sales Increased 28 Percent To $736 Million

Adjusted Net Income Increased 10 Percent To $158 Million

Board Concludes That Teva Pharmaceuticals Offer Maximizes Cephalon Shareholder Value

Frazer, Pa. — May 3, 2011 — Cephalon, Inc. (Nasdaq: CEPH) today reported first quarter 2011 net sales of $736.0 million, a 28 percent increase compared to net sales of $576.7 million for the first quarter of 2010.  Basic income per common share for the period was $2.79.  Excluding amortization expense and certain other items, adjusted net income for the first quarter of 2011 was $158.4 million, a 10 percent increase over the same period in 2010.  Basic adjusted income per common share for the quarter was $2.09, a 9 percent increase over the $1.92 for the first quarter of 2010.  Sales and earnings were within the previously announced guidance range.

Central nervous system (CNS) franchise net sales were $334.7 million during the quarter, a 7 percent increase compared to the same period last year.  Pain franchise reported net sales of $130.5 million, a 13 percent increase versus first quarter 2010.  Oncology franchise net sales were $149.1 million, a 35 percent increase over the same period last year due to strong net sales of TREANDA® (bendamustine hydrochloride) of $117.7 million.  Sales of other products increased to $121.6 million, from $38.3 million in 2010, primarily due to the addition of Mepha products sales.

During the first quarter 2011 Cephalon recorded net cash provided by operating activities of $147.8 million and ended the period with $1.16 billion of cash and cash equivalents.

On May 2, 2011 Cephalon announced the signing of a definitive agreement under which Teva Pharmaceutical Industries Ltd. will acquire all of the outstanding shares of Cephalon for $81.50 per share in cash.

“After analyzing a full range of strategic options our Board concluded that the Teva offer provides the maximum shareholder value for Cephalon shareholders,” said Kevin Buchi, Chief Executive Officer. “Based on these 2011 quarterly earnings, Cephalon is once again off to

SOURCE:  Cephalon, Inc. · 41 Moores Road · Frazer, PA  19355 · (610) 344-0200 · Fax (610) 344-0065

another very strong start.  Given this performance, we expect that our full year earnings will meet or even exceed our previous guidance.  However, due to our pending merger with Teva announced on Monday, we will no longer be providing 2011 guidance.”

About Cephalon, Inc.

Cephalon is a global biopharmaceutical company dedicated to discovering, developing and bringing to market medications to improve the quality of life of individuals around the world.  Since its inception in 1987, Cephalon has brought first-in-class and best-in-class medicines to patients in several therapeutic areas.  Cephalon has the distinction of being one of the world’s fastest-growing biopharmaceutical companies, now among the Fortune 1000 and a member of the S&P 500 Index, employing approximately 4,000 people worldwide.  The company sells numerous branded and generic products around the world. In total, Cephalon sells more than 150 products in approximately 100 countries.  More information on Cephalon and its products is available at http://www.cephalon.com

# # #

In addition to historical facts or statements of current condition, this press release may contain forward-looking statements. Forward-looking statements provide Cephalon’s current expectations or forecasts of future events. These may include statements regarding Teva’s proposed acquisition of Cephalon; anticipated scientific progress on its research programs; development of potential pharmaceutical products; interpretation of clinical results; prospects for regulatory approval; manufacturing development and capabilities; market prospects for its products; and other statements regarding matters that are not historical facts. You may identify some of these forward-looking statements by the use of words in the statements such as “anticipate,” “estimate,” “expect,” “project,” “intend,” “plan,” “believe” or other words and terms of similar meaning. Cephalon’s performance and financial results could differ materially from those reflected in these forward-looking statements due to general financial, economic, regulatory and political conditions affecting the biotechnology and pharmaceutical industries as well as more specific risks and uncertainties facing Cephalon such as those set forth in its reports on Form 8-K, 10-Q and 10-K filed with the U.S. Securities and Exchange Commission. Given these risks and uncertainties, any or all of these forward-looking statements may prove to be incorrect. Therefore, you should not rely on any such factors or forward-looking statements. Furthermore, Cephalon does not intend to update publicly any forward-looking statement, except as required by law. The Private Securities Litigation Reform Act of 1995 permits this discussion.

This press release and/or the financial results attached to this press release include “Adjusted Net Income,” “Basic Adjusted Income per Common Share,” “Adjusted Net Income Guidance,” “Basic Adjusted Income per Common Share Guidance,” and “Diluted Adjusted Income Per Common Share,” amounts that are considered “non-GAAP financial measures” under SEC rules. As required, we have provided reconciliations of these measures. Additional required information is located in the Form 8-K furnished to the SEC in connection with this press release.

Source: Cephalon, Inc.

2

3

CEPHALON, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share data)

(Unaudited)

CEPHALON, INC. AND SUBSIDIARIES

Reconciliation of GAAP Net Income (Loss) to Adjusted Net Income

(Unaudited)

Notes to Reconciliation of GAAP Net Income (Loss) to Adjusted Net Income

*                 Amounts recorded by our Variable Interest Entities that have been excluded from net income attributable to Cephalon, Inc.

(1)          To exclude the on-going amortization of acquired intangible assets ($29.1M in 2011; $25.8M in 2010) and accelerated depreciation related to restructuring ($5.2M in 2010).

(2)          To exclude accelerated depreciation related to restructuring.

(3)          To exclude charges related to the acquisition of Mepha GmbH ($0.7M in 2011; $2.3M in 2010), Mesoblast Limited ($0.1M in 2011) and GeminX Pharmaceuticals ($0.1M in 2011).

(4)          In 2011, to exclude the change in fair value of the Ception Therapeutics, Inc. ($1.3M) and BioAssets Development Company ($0.5M) contingent consideration.

(5)          To exclude costs related to restructurings.

(6)          In 2011, to exclude costs related to the acquisition of worldwide license rights to Mesoblast Limited’s proprietary technology platform.

(7)          In 2011, to exclude costs associated with our plan to sell our manufacturing facility in Mitry Mory, France ($6.1M), offset by a gain on the sale of our facility in Savigny le Temple, France ($0.4M).

(8)          To exclude imputed interest expense associated with convertible debt.

(9)          In 2011, to exclude the change in fair value of our investments in Mesoblast Limited ($159.6M) and ChemGenex Pharmaceuticals Limited ($5.1M).

(10)    To exclude losses on currency forward contracts and options used to manage foreign exchange rate risk related to the Mesoblast acquisition in 2011 and the Mepha GmbH acquisition in 2010.

(11)    To reflect the tax effect of pre-tax adjustments at the applicable tax rates and certain other tax adjustments primarily related to changes in valuation allowances, and other changes in tax assets and liabilities.

CEPHALON, INC. AND SUBSIDIARIES

CONSOLIDATED SALES DETAIL

(In thousands)

(Unaudited)

CEPHALON, INC. AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(In thousands, except share data)

(Unaudited)

CEPHALON, INC. AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

(Unaudited)