X0306 4 2020-06-11 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001229450 WHEELER CRAIG A C/O MOMENTA PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 1 1 0 0 President & CEO Common Stock 2020-06-11 4 A 0 83500 0 A 92239 D Common Stock 2020-06-12 4 S 0 37575 30.56 D 54664 D Common Stock 36725 I Craig A Wheeler 2016 Annuity Trust Common Stock 48263 I Craig A Wheeler 2018 Annuity Trust Common Stock 481172 I Craig Wheeler Revocable Trust Restricted Stock Units 2020-06-11 4 A 0 83500 0 A Common Stock 83500 167000 D Shares received pursuant to settlement of Performance Stock Units that were granted on December 21, 2018. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 17, 2019. This transaction was executed in multiple trades at prices ranging from $29.65 to $31.37. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote. Reflects a decrease of 6,574 shares of MNTA common stock transferred to the Craig Wheeler Revocable Trust on May 20, 2020. Reflects the transfer of 6,574 shares of MNTA common stock on May 20, 2020 that were previously held in the Craig A. Wheeler personal account. Each Restricted Stock Unit represents a contingent right to receive one share of MNTA Common Stock. Subject to the officer's continued employment with the company, 83,500 Restricted Stock Units will vest on June 11, 2021. /s/ R. Mark Chamberlin as attorney in fact 2020-06-15