Amended Statement of Ownership: Solicitation (sc 14d9/a)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 14D-9

(Rule 14d-101)

Solicitation/Recommendation Statement

Under Section 14(d)(4) of the Securities Exchange Act of 1934

Amendment No. 5

Dimension Therapeutics, Inc.

(Name of Subject Company)

Dimension Therapeutics, Inc.

(Name of Person(s) Filing Statement)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

25433V105

(CUSIP Number of Class of Securities)

Annalisa Jenkins, M.B.B.S, F.R.C.P

President and Chief Executive Officer

840 Memorial Drive

Cambridge, MA 02139

(617) 401-0011

(Name, Address and Telephone Number of Person Authorized to Receive Notice and Communications

on Behalf of the Person(s) Filing Statement)

With copies to:

Kingsley L. Taft, Esq.

Andrew H. Goodman, Esq.

Goodwin Procter LLP

100 Northern Avenue

Boston, MA 02110

(617) 570-1000

☐

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

This Amendment No. 5 (this “ Amendment ”) amends and supplements the Solicitation/Recommendation Statement on Schedule 14D-9 filed with the U.S. Securities and Exchange Commission (the “ SEC ”) on October 10, 2017 (together with the exhibits thereto and as amended or supplemented from time to time, the “ Schedule 14D-9 ”) by Dimension Therapeutics, Inc., a Delaware corporation (the “ Company ”). The Schedule 14D - 9 relates to the cash tender offer by Mystic River Merger Sub Inc., a Delaware corporation (“ Purchaser ”), a subsidiary of Ultragenyx Pharmaceutical Inc., a Delaware corporation (“ Ultragenyx ”), to purchase all of the issued and outstanding shares of the Company’s common stock, par value $0.0001 per share (the “ Shares ”) at a price per Share equal to $6.00, net to the holder in cash, without interest thereon and subject to any required tax withholding. The tender offer is disclosed in the Tender Offer Statement on Schedule TO filed by Ultragenyx and Purchaser with the SEC on October 10, 2017, and is made upon the terms and subject to the conditions set forth in the Offer to Purchase dated October 10, 2017, and in the related Letter of Transmittal, which were filed as Exhibits (a)(1)(A) and (a)(1)(B) to the Schedule 14D-9, respectively.

Capitalized terms used, but not otherwise defined, in this Amendment shall have the meanings ascribed to them in the Schedule 14D-9. The information in the Schedule 14D-9 is incorporated into this Amendment by reference to all applicable items in the Schedule 14D-9, except that such information is hereby amended and supplemented to the extent specifically provided herein.

Item 8. Additional Information.

Item 8 of the Schedule 14D-9 is hereby amended and supplemented by replacing the last paragraph of the subsection entitled “ Regulatory Approvals. – U.S. Antitrust Laws, ” which begins on page 51 of the Schedule 14D-9, as such paragraph was added by Amendment No. 1 to the Schedule 14D-9 on October 11, 2017, with the following paragraph:

“On October 10, 2017, each of Ultragenyx and the Company filed a Premerger Notification and Report Form with the FTC and the Antitrust Division in connection with the purchase of Shares in the Offer. The required waiting period under the HSR Act with respect to the Offer expired at 11:59 p.m., Eastern Time on October 25, 2017. Accordingly, the HSR Condition (as defined in the Offer to Purchase) in Section 13—“Conditions of the Offer” of the Offer to Purchase has been satisfied.”

Item 9. Exhibits

Item 9 of the Schedule 14D-9 is hereby amended and supplemented by adding the following exhibit:


(a)(5)(B)		Joint Press Release of Ultragenyx and the Company, dated October 26, 2017, announcing expiration of the waiting period under the HSR Act.

SIGNATURE

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.

Dated: October 26, 2017