X0202 4 2005-12-15 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001294276 Sasisekharan Ram C/O MOMENTA PHARMACEUTICALS, INC. 675 WEST KENDALL STREET CAMBRIDGE MA 02142 1 0 0 0 Common Stock 2005-12-15 4 S 0 10000 25.12 D 768344 D Common Stock 2005-12-15 4 S 0 1920 25.26 D 766424 D Common Stock 2005-12-15 4 S 0 400 25.28 D 766024 D Common Stock 2005-12-15 4 S 0 500 25.29 D 765524 D Common Stock 2005-12-15 4 S 0 100 25.35 D 765424 D Common Stock 2005-12-15 4 S 0 2013 25.36 D 763411 D Common Stock 2005-12-15 4 S 0 380 25.37 D 763031 D Common Stock 2005-12-15 4 S 0 87 25.38 D 762944 D Common Stock 2005-12-15 4 S 0 600 25.4 D 762344 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 7, 2005. /s/ Michael Morneau, as Attorney-in-Fact 2005-12-19