X0306 4 2017-06-20 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) 17.20 2017-06-20 4 A 0 11207 0 A 2027-06-20 Common Stock 11207 11207 D Restricted Stock Units 2017-06-20 4 A 0 5734 0 A Common Stock 5734 5734 D Represents an option granted by the Company pursuant to the Company's 2013 Incentive Award Plan. The stock option will vest and become exercisable on the first anniversary of the grant date, subject to Mr. Downey's continued service to the Company. Each restricted stock unit represents a contingent right to receive one share of MNTA common stock. Represents 5,734 restricted stock units, awarded pursuant to the Company's 2013 Incentive Award Plan, 100% of the restricted stock units shall vest on the first anniversary of the grant date, subject to Mr. Downey's continued service to the Company. /s/ Christopher S. Kiefer as attorney in fact 2017-06-22