X0306 4 2020-01-14 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001755174 BELTRAMELLO JO ANN C/O MOMENTA PHARMACEUTICALS, INC. 301 BINNEY ST, CAMBRIDGE MA 02142 0 1 0 0 Chief HR and Inf. Officer CommonStock 2020-01-14 4 M 0 2362 10.83 A 46078 D Common Stock 2020-01-14 4 M 0 30800 12.58 A 76878 D Common Stock 2020-01-14 4 M 0 36485 13.02 A 113363 D Common Stock 2020-01-14 4 M 0 25495 13.26 A 138858 D Common Stock 2020-01-14 4 M 0 26183 15.44 A 165041 D Common Stock 2020-01-14 4 S 0 2362 21.35 D 162679 D Common Stock 2020-01-14 4 S 0 30800 22.58 D 131879 D Common Stock 2020-01-14 4 S 0 36485 23.02 D 95394 D Common Stock 2020-01-14 4 S 0 25495 23.26 D 69899 D Common Stock 2020-01-14 4 S 0 26183 25.44 D 43716 D Common Stock 2020-01-14 4 S 0 1264 20.47 D 42452 D Stock Option (Right to Buy) 10.83 2020-01-14 4 M 0 1493 0 A 2019-02-09 2026-02-09 Common Stock 1493 6843 D Stock Option (Right to Buy) 10.83 2020-01-14 4 M 0 869 0 A 2017-02-09 2026-02-09 Common Stock 869 28595 D Stock Option (Right to Buy) 13.26 2020-01-14 4 M 0 11240 0 A 2015-02-22 2021-02-22 Common Stock 11240 0 D Stock Option (Right to Buy) 13.26 2020-01-14 4 M 0 14255 0 A 2013-11-22 2021-02-22 Common Stock 14255 0 D Stock Option (Right to Buy) 12.58 2020-01-14 4 M 0 22935 0 A 2016-11-19 2023-02-19 Common Stock 22935 0 D Stock Option (Right to Buy) 12.58 2020-01-14 4 M 0 7895 0 A 2017-02-19 2023-02-19 Common Stock 7895 0 D Stock Option (Right to Buy) 13.02 2020-01-14 4 M 0 36485 0 A 2018-11-18 2025-02-18 Common Stock 36485 0 D Stock Option (Right to Buy) 15.44 2020-01-14 4 M 0 19357 0 A 2015-11-14 2022-02-14 Common Stock 19357 0 D Stock Option (Right to Buy) 15.44 2020-01-14 4 M 0 6826 0 A 2016-02-14 2022-02-14 Common Stock 6826 0 D This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the person on November 7, 2019. This transaction was executed in multiple trades at prices ranging from $21.34 to $21.37. 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. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 14, 2018. /s/ R. Mark Chamberlin as attorney in fact 2020-01-16