This Amendment No. 3 (this “Amendment”) amends and supplements the Tender Offer
Statement on Schedule TO (as amended and together with any subsequent amendments and supplements thereto, the “Schedule TO”), filed with the U.S. Securities and Exchange Commission (“SEC”) on September 2, 2020,
by Vigor Sub, Inc., a Delaware corporation (“Purchaser”) and a wholly owned subsidiary of Johnson & Johnson, a New Jersey corporation (“Johnson & Johnson”), and Johnson &
Johnson. The Schedule TO relates to the tender offer by Purchaser for all of the outstanding shares of common stock, par value $0.0001 per share (the “Shares”), of Momenta Pharmaceuticals, Inc., a Delaware corporation
(“Momenta”), at a price of $52.50 per Share, net to the seller in cash, without interest and less any required withholding taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated as of
September 2, 2020 (together with any amendments and supplements thereto, the “Offer to Purchase”), and in the related Letter of Transmittal (together with any amendments and supplements thereto, the “Letter of
Transmittal”), copies of which are attached to the Schedule TO as exhibits (a)(1)(A) and (a)(1)(B), respectively.
Except to the extent
specifically provided in this Amendment, the information set forth in the Schedule TO remains unchanged. This Amendment is being filed to reflect certain updates as reflected below.
Item 11. Additional Information.
The Offer to Purchase and Item 11 of the Schedule TO, to the extent such Item incorporates by reference the information contained in the Offer to Purchase, are
hereby amended and supplemented by replacing the paragraph under the heading “Litigation” in Section 16—“Certain Legal Matters; Regulatory Approvals” of the Offer to Purchase with the following:
“On September 2, 2020, a purported stockholder of Momenta filed a complaint in the United States District Court for the District of Delaware against
Momenta and its directors, captioned Elaine Wang v. Momenta Pharmaceuticals, Inc., et al., Case No. 1:20-cv-01175-UNA (the
“Wang Complaint”). On September 8, 2020, a purported stockholder of Momenta filed a complaint in the United States District Court for the Southern District of New York against Momenta and its directors, captioned Rudik v.
Momenta Pharmaceuticals, Inc., et al., Case No. 1:20-cv-07313 (the “Rudik Complaint”). On September 9, 2020, a purported stockholder of Momenta
filed a complaint in the United States District Court for the District of Delaware against Momenta, its directors, Johnson & Johnson and Purchaser, captioned Post v. Momenta Pharmaceuticals, Inc., et al., Case No. 1:99-mc-09999 (the “Post Complaint”). On September 11, 2020, a purported stockholder of Momenta filed a complaint in the United States District Court for
the Southern District of New York against Momenta and its directors, captioned Booth Family Trust v. Momenta Pharmaceuticals, Inc., et al., Case No. 1:20-cv-07461
(the “Booth Complaint”). On September 22, 2020, a purported stockholder of Momenta filed a complaint in the United States District Court for the Southern District of New York against Momenta and its directors, captioned David
Nowak v. Momenta Pharmaceuticals, Inc., et al., Case No. 1:20-cv-07782 (the “Nowak Complaint”). On September 22, 2020, a purported stockholder of Momenta filed a complaint in the Supreme Court of the State of New York for the
County of New York against Momenta and its directors, captioned David Nowak v. Momenta Pharmaceuticals, Inc., et al., Case No. 654613/2020 (the “Second Nowak Complaint”). On September 22, 2020, a purported stockholder
of Momenta filed a complaint in the United States District Court for the Southern District of New York against Momenta and its directors, captioned Carlos Cespedes v. Momenta Pharmaceuticals, Inc., et al., Case No. 1:20-cv-07804 (the
“Cespedes Complaint”).
The complaints in the preceding paragraph name as defendants Momenta and each member of the Momenta Board. The
Post Complaint also names Johnson & Johnson and Purchaser as defendants. Each of the complaints (except the Second Nowak Complaint) alleges that the Schedule 14D-9 omits material information or
contains misleading disclosures and that, as a result, (a) all defendants violated Section 14(e) of the Exchange Act, (b) all defendants violated Section 14(d)(4) of the Exchange Act and (c) each member of the Momenta Board
(and Johnson & Johnson in the Post Complaint) violated Section 20(a) of the Exchange Act. The Nowak Complaint also alleges that each member of the Momenta Board breached their fiduciary duties of candor and disclosure. The Second Nowak
Complaint alleges that each member of the Momenta Board breached their fiduciary duties of care, loyalty and good faith and that Momenta aided and abetted the Momenta Board in such breach. Each of the complaints seeks, among other things,
(i) injunctive relief preventing the consummation of the transactions contemplated by the Merger Agreement, (ii) rescissory damages or rescission in the event that the transactions contemplated by the Merger Agreement have already been
consummated (except for the Rudik Complaint), (iii) damages (except for the Post, Booth and Cespedes Complaints) and (iv) plaintiff’s attorneys’ and experts’ fees and expenses. The Rudik, Post and Cespedes Complaints also seek an
amendment to the Schedule 14D-9 that addresses their complaints. Momenta believes the claims asserted in each of the complaints are without merit.
Additional complaints may be filed against Momenta, the Momenta Board, Johnson & Johnson and/or Purchaser in connection with the transactions
contemplated by the Merger Agreement, the Schedule TO and the Schedule 14D-9. If such additional complaints are filed, absent new or different allegations that are material, Johnson & Johnson and
Purchaser will not necessarily announce such additional complaints.”