SEPR Sepracor Inc. (MM)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO/A

TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR SECTION 13(E)(1)

OF THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

SEPRACOR INC.

(Name of Subject Company)

APTIOM, INC.

DAINIPPON SUMITOMO PHARMA CO., LTD.

(Names of Filing Persons (Offerors))

COMMON STOCK, PAR VALUE $0.10 PER SHARE

(INCLUDING ASSOCIATED PREFERRED STOCK PURCHASE RIGHTS)

(Title of Class of Securities)

817315104

(CUSIP Number of Class of Securities)

Noriaki Okuda

Director, Legal Affairs

Dainippon Sumitomo Pharma Co., Ltd.

6-8, Doshomachi 2-Chome, Chuo-Ku, Osaka, 541-0045, Japan

Tel: +81-6-6203-4690

Fax: +81-6-6203-2129

(Name, Address and Telephone Number of Person Authorized

to Receive Notices and Communications on Behalf of Filing Persons)

Copies to:

Toby S. Myerson, Esq.

Ariel J. Deckelbaum, Esq.

1285 Avenue of the Americas

New York, NY 10019-6064

United States

Phone 212-373-3000

Fax 212-757-3990

CALCULATION OF FILING FEE

*                                          Estimated for purposes of calculating the filing fee only. This amount is based on the offer to purchase at a purchase price of $23.00 cash per share (i) all 110,992,118 outstanding shares of common stock of Sepracor; (ii) all restricted stock units with respect to 58,711 shares of common stock of Sepracor; and (iii) all outstanding options with an exercise price equal to or less than $23.00 with respect to 4,376,328 shares of common stock of Sepracor net of the weighted average exercise price of $16.96 per share option, in each case as of August 31, 2009, the most recent practicable date.

**                                   The amount of the filing fee is calculated in accordance with Rule 0-11 of the Securities Exchange Act of 1934, as amended, by multiplying the transaction valuation by 0.00005580.

x                                   Check box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

o                                     Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

x                                   third-party tender offer subject to Rule 14d-1.

o                                     issuer tender offer subject to Rule 13e-4.

o                                     going-private transaction subject to Rule 13e-3.

o                                     amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer.  o

This Amendment No. 2 (this “Amendment ”) amends and supplements the Tender Offer Statement on Schedule TO filed on September 15, 2009, as amended and supplemented by Amendment No. 1 filed on September 24, 2009 (as so amended and supplemented, the “ Schedule TO ”) by Aptiom, Inc. (“ Offeror ”), a Delaware corporation and an indirect wholly-owned subsidiary of Dainippon Sumitomo Pharma Co., Ltd. (“ DSP ”), a corporation organized under the laws of Japan, to purchase all of the outstanding shares of common stock, par value $0.10 per share (together with the associated preferred stock purchase rights, each a “ Share ” and collectively, the “ Shares ”), of Sepracor Inc., a Delaware corporation (“ Sepracor ”), at a purchase price of $23.00 per Share, net to the seller in cash, without interest thereon and less any applicable withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase dated September 15, 2009 (the “ Offer to Purchase ”) and the related Letter of Transmittal (the “ Letter of Transmittal ” which, together with the Offer to Purchase, as each may be amended and supplemented from time to time, constitute the “ Offer ”). The Schedule TO was filed on behalf of Offeror and DSP.  Capitalized terms used and not otherwise defined herein shall have the meanings ascribed to such terms in the Offer to Purchase.

The information in the Offer to Purchase and the Letter of Transmittal is incorporated into this Amendment by reference to all of the applicable items in the Schedule TO, except that such information is hereby amended and supplemented to the extent provided herein.

ITEM 4.  TERMS OF THE TRANSACTION

Item 4 of the Schedule TO is hereby amended and supplemented as follows:

The third paragraph in Section 15 “Conditions of the Offer” is amended to add the following sentence at the end thereof:

“In determining whether or not the condition set forth in sub-paragraph (c) of the paragraph immediately above has been satisfied, Aptiom and Offeror intend to act in a manner consistent with the terms of the Merger Agreement and the applicable laws of the State of Delaware, which govern the Merger Agreement.  Delaware courts have determined that, when exercising their contractual rights, parties to an agreement, such as the Merger Agreement, are subject to an implied covenant of good faith and fair dealing.”

ITEM 11.  ADDITIONAL INFORMATION

Item 11 of the Schedule TO is hereby amended and supplemented as follows:

The disclosure under the heading entitled “Sepracor Projections” in Section 8 “Certain Information Concerning Sepracor” of the Offer to Purchase is hereby amended and supplemented by amending and restating the third sentence of the first paragraph thereunder in its entirety as follows:

“In connection with DSP’s due diligence review and the execution of the Merger Agreement, DSP and Offeror did not review any probability- or risk-adjusted projections prepared by Sepracor.”

The disclosure under the heading entitled “Legal Proceedings” in Section 16 “Certain Legal Matters; Regulatory Approvals” of the Offer to Purchase is hereby amended and supplemented by adding the following paragraphs below the second paragraph thereof:

“On September 23, 2009, another action purporting to be brought on behalf of a class of stockholders of Sepracor, captioned John Perrotta v. Sepracor, Inc., et al. , No. 1:09-cv-11585 (filed September 23, 2009), was filed in Massachusetts Federal District Court alleging that the members of the Sepracor Board breached their fiduciary duties to Sepracor’s stockholders by, among other things, failing to take steps to maximize shareholder value and taking steps to avoid competitive bidding in connection with the Offer and that Sepracor, DSP and Offeror aided and abetted the purported breaches of fiduciary duties.  The complaint further alleges that Sepracor violated the Exchange Act by omitting and misrepresenting facts in Sepracor’s Schedule 14D-9.  The plaintiffs in this action request, among other things, to enjoin the Offer and Merger until Sepracor adopts or implements a procedure or process to obtain the highest possible price for the shareholders.

On September 25, 2009, the Massachusetts Superior Court granted Defendants’ Motion to Stay the Giaquinto Action pending the outcome of the Delaware litigation.

On October 2, 2009, parties to the consolidated Delaware Chancery Court action executed a Memorandum of Understanding (“MOU”), pursuant to which, inter alia , Sepracor would make additional public disclosures (which are incorporated into Amendment No. 2 to the Schedule 14D-9 filed by Sepracor on October 2, 2009), and all claims in the consolidated Delaware Chancery Court action would be dismissed in accordance with the terms of the MOU. The settlement of the consolidated Delaware Chancery Court action is subject to negotiation of definitive settlement documentation and approval by the Delaware Court of Chancery and is conditioned upon consummation of the Merger.”

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SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

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EXHIBIT INDEX

*  Previously filed.

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