Merck Prices $8.0 Billion Debt Offering

Merck & Co., Inc. (the “Company”) (NYSE:MRK), known as MSD outside of the United States and Canada, priced today an $8.0 billion public offering of senior unsecured notes (collectively, the “Notes”). The Notes include:

$300 million of floating rate notes due February 2017

$700 million of floating rate notes due February 2020

$1,250 million of 1.850% notes due February 2020

$1,250 million of 2.350% notes due February 2022

$2,500 million of 2.750% notes due February 2025

$2,000 million of 3.700% notes due February 2045

The Company intends to use a substantial portion of the net proceeds of the offering to repay commercial paper issued to substantially finance the Company’s acquisition of Cubist Pharmaceuticals, Inc., which closed on Jan. 21, 2015. Any remaining net proceeds will be used for general corporate purposes, including without limitation repurchases of the Company’s common stock, and the repayment of outstanding commercial paper borrowings and upcoming debt maturities. The offering is expected to close on Feb. 10, 2015, subject to customary closing conditions. J.P. Morgan Securities LLC, Deutsche Bank Securities Inc. and Credit Suisse Securities (USA) LLC are acting as the active joint book-running managers for the offering.

The offering of the Notes is being made pursuant to an effective shelf registration statement (including a base prospectus) filed with the Securities and Exchange Commission (the “SEC”). The offering may be made only by means of a prospectus and related prospectus supplement, copies of which may be obtained by calling J.P. Morgan Securities LLC at (212) 834-4533 (collect), Deutsche Bank Securities Inc. at (800) 503-4611 (toll-free) or Credit Suisse Securities (USA) LLC at (800) 221-1037 (toll-free). An electronic copy of the registration statement and prospectus supplement, together with the base prospectus, is available on the SEC’s website at www.sec.gov.

This press release does not constitute an offer to sell or a solicitation of an offer to buy the securities described herein, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.

About Merck

Today’s Merck is a global health care leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to health care through far-reaching policies, programs and partnerships.

Merck Forward-Looking Statement

This news release includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. Such statements may include, but are not limited to, Merck’s ability to complete the offering and Merck’s expectations for the use of proceeds from the offering. These statements are based upon the current beliefs and expectations of Merck’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline products that the products will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Merck’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of Merck patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions; and timing of the offering.

Merck undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise except as required by applicable law. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in Merck’s 2013 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).