X0306 4 2020-06-23 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001415739 Stoner Elizabeth C/O MOMENTA PHARMACEUTICALS, INC. 301 BINNEY STREET CAMBRIDGE MA 02142 1 0 0 0 Stock Option (Right to Buy) 38.09 2020-06-23 4 A 0 25000 0 A 2030-06-23 Common Stock 25000 25000 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 Dr. Stoner's continued service to the Company. /s/ R. Mark Chamberlin as attorney in fact 2020-06-24