Sepracor Announces Tender Offer for 0% Convertible Senior Subordinated Notes Due 2024

Sepracor Inc. (“Sepracor”) today announced that it has commenced a tender offer to repurchase for cash up to all $279,000 aggregate principal amount of its outstanding 0% Convertible Senior Subordinated Notes due 2024 (the “Notes”). The tender offer will expire at 5:00 p.m., New York City time, on Tuesday, December 1, 2009, unless the tender offer is extended by Sepracor (such date, as it may be extended, the “Expiration Date”). The terms and conditions of the tender offer are set forth in a Notice of Designated Event and Offer to Purchase (the “Offer to Purchase”) and a related Letter of Transmittal to be distributed to holders of Notes (“Holders”).

Sepracor is offering to repurchase all of the outstanding Notes at a price of $1,000.00 per $1,000.00 principal amount of Notes, plus any accrued and unpaid liquidated damages on the Notes to, but excluding, the Expiration Date. The tender offer has been commenced by Sepracor pursuant to the terms of that certain Indenture, dated as of September 22, 2004 (as subsequently supplemented, the “Indenture”), between Sepracor and The Bank of New York Mellon (as successor to JPMorgan Chase Bank), as trustee (the “Trustee”), governing the Notes, as a result of the occurrence of a “Designated Event” (as defined in the Indenture). The Designated Event occurred on October 15, 2009 following the expiration of the initial offering period of a tender offer to acquire all of the outstanding common stock of Sepracor commenced by Aptiom, Inc., a Delaware corporation and an indirect wholly-owned subsidiary of Dainippon Sumitomo Pharma Co., Ltd., a joint stock corporation incorporated under the laws of Japan (“DSP”).

Holders with questions regarding the tender offer may contact The Bank of New York Mellon, in its capacity as depositary for the tender offer (the “Depositary”), at (212) 815-8394 or Sepracor at (508) 787-4289. Requests for additional copies of the Offer to Purchase, the Letter of Transmittal or other related documents should be directed to the Depositary at the number listed above.

None of Sepracor, DSP, or any of their respective affiliates, officers, or directors or the Trustee or the Depositary make any recommendation as to whether or not Holders should tender their Notes pursuant to the tender offer. Holders must decide how many Notes they will tender, if any.

This press release is for informational purposes only and does not constitute an offer to purchase nor a solicitation for acceptance of the tender offer described above. The tender offer is being made solely pursuant to the Offer to Purchase, Letter of Transmittal and related materials that the Depositary will distribute to Holders. Holders should read carefully the Offer to Purchase, Letter of Transmittal and related materials because they contain important information regarding the tender offer.

About Sepracor

Sepracor is a fully integrated specialty pharmaceutical company dedicated to treating and preventing human disease by discovering, developing and commercializing innovative pharmaceutical products that are directed toward serving large and growing markets and unmet medical needs. Sepracor’s drug development, corporate development, and licensing efforts have yielded a portfolio of pharmaceutical products and candidates with a focus on respiratory and central nervous system disorders. Sepracor’s currently marketed products in the U.S. include LUNESTA^® brand eszopiclone, XOPENEX^® brand levalbuterol HCl Inhalation Solution, XOPENEX HFA^® brand levalbuterol tartrate Inhalation Aerosol, BROVANA^® brand arformoterol tartrate Inhalation Solution, OMNARIS^® brand ciclesonide Nasal Spray and ALVESCO^® brand ciclesonide HFA Inhalation Aerosol. Sepracor’s wholly owned subsidiary, Sepracor Pharmaceuticals, Inc., markets several additional products in Canada that are focused in the cardiovascular, central nervous system, pain and infectious disease therapeutic areas. Sepracor has approximately 2,100 employees worldwide. Additional information about Sepracor is available through its corporate web site at http://www.sepracor.com.

Forward-Looking Statements

This announcement contains forward-looking statements that involve significant risks and uncertainties. All statements that are not historical facts are forward-looking statements, including statements regarding the expected timing of the Expiration Date, and any statements of assumptions underlying any of the foregoing. Investors and security holders are cautioned not to place undue reliance on these forward-looking statements. Sepracor does not undertake any obligation to update or revise any forward-looking statements as a result of new information, future developments or otherwise.

Lunesta, Xopenex, Xopenex HFA and Brovana are registered trademarks of Sepracor Inc. Omnaris and Alvesco are registered trademarks of Nycomed GmbH.

For a copy of this release or any recent release, visit Sepracor’s web site at www.sepracor.com.