X0306 4 2013-02-19 0 0001113481 MEDICINES CO /DE MDCO 0001318459 Antinori Paul Michael 8 SYLVAN WAY PARSIPPANY NJ 07054 0 1 0 0 Sr. VP & General Counsel Common Stock 2013-02-19 4 S 0 569 31.81 D 45469 D Common Stock 2013-02-20 4 M 0 6500 18.27 A 51969 D Common Stock 2013-02-20 4 S 0 6500 32.50 D 45469 D Option (right to buy) 18.27 2013-02-20 4 M 0 6500 0 D 2015-11-30 Common Stock 6500 0 D Represents the number of shares sold to cover the tax expense associated with the vesting of restricted shares held by Mr. Antinori pursuant to his Restricted Stock Agreements with the Company. The range of prices for the transactions reported on this line is between $31.77 and $31.88 per share. The price reported above reflects the weighted average sales price. The undersigned undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price. The common stock sales reported on this line of the Form 4 were effected pursuant to a Rule 10b5-1 program adopted by Mr. Antinori on August 10, 2012. As of 2/20/2013, the original grant (12,500 shares granted on 11/30/2005) was fully vested. After the exercise of the options reported hereby, as of 2/20/2013, all shares covered by this option have been exercised. /s/ Paul M. Antinori 2013-02-21