On April 21, 2017, the Board of Directors (the “Board”) of PTC Therapeutics, Inc. (the “Company”) amended and restated the Company’s Amended and Restated Bylaws (as amended, the “Bylaws”), effective immediately, to implement a proxy access provision. The Bylaws include a new Section 1.12 in Article I, which permits a stockholder, or a group of up to 20 stockholders, owning an amount of shares that constitutes 3% or more of the Company’s outstanding common stock as of both the date of the nomination and the record date for determining stockholders entitled to vote at the annual meeting, and continuing to own the shares through the annual meeting date, continuously for at least three years to nominate and include in the Company’s proxy materials director nominees constituting up to 25% of the Board, subject to the terms and conditions set forth in the Bylaws. Written notice of any nominations to the new Section 1.12 must be submitted to the Secretary of the Company at the principal executive offices of the Company not less than ninety days nor more than one hundred twenty days prior to the anniversary of the date of the preceding year’s annual meeting of stockholders, subject to the terms and conditions set forth in the Bylaws. In addition, Section 1.12 includes other requirements that nominating stockholders and nominees must satisfy in order for the nominees to be included in the Company’s proxy materials.

The Board also made certain other conforming, clarifying and administrative changes to the Bylaws to implement Section 1.12.

The foregoing description of the amendments to the Bylaws does not purport to be complete and is qualified in its entirety by reference to the full text of the Bylaws, a copy of which is attached hereto as Exhibit 3.1 and is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

See Exhibit Index attached hereto.

About PTC THERAPEUTICS, INC. (NASDAQ:PTCT)

PTC Therapeutics, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of orally administered, small molecule therapeutics that focus on post-transcriptional control processes. The Company’s lead product, Translarna (ataluren), is used for the treatment of nonsense mutation Duchenne muscular dystrophy (nmDMD) in ambulatory patients with age of over five years and older. Its programs include Translarna for nonsense mutation cystic fibrosis (nmCF), Translarna for mucopolysaccharidosis type I caused by nonsense mutation (nmMPS I), Translarna for nonsense mutation aniridia, Translarna for nonsense mutation Dravet syndrome/CDKL5, Spinal muscular atrophy (SMA) in collaboration with Spinal Muscular Atrophy Foundation (SMA Foundation) and F. Hoffman-La Roche Ltd and Hoffman- La Roche Inc. (collectively Roche), and Cancer stem cell program (PTC596). It has two compounds in clinical development within the SMA program: RG7800 and RG7916.

PTC THERAPEUTICS, INC. (NASDAQ:PTCT) Recent Trading Information

PTC THERAPEUTICS, INC. (NASDAQ:PTCT) closed its last trading session up +0.12 at 11.37 with 2,546,018 shares trading hands.