X0306 4 2015-06-10 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001237257 DOWNEY BRUCE C/O MOMENTA PHARMACEUTICALS, INC. 675 WEST KENDALL STREET CAMBRIDGE MA 02142 1 0 0 0 Stock Option (Right to Buy) 22.18 2015-06-10 4 A 0 17750 0 A 2015-09-10 2025-06-10 Common Stock 17750 123750 D Represents an option granted by the issuer pursuant to the issuer's 2013 Stock Incentive Plan. Subject to certain criteria, the shares subject to such option vest in four equal quarterly installments following the grant date. Includes multiple option grants with different pricing and vesting. /s/ Marie T. Washburn as attorney in fact 2015-06-10