X0306 4 2016-02-02 0 0001552451 MyoKardia Inc MYOK 0001654909 Bauer Jake C/O MYOKARDIA, INC. 333 ALLERTON AVENUE SOUTH SAN FRANCISCO CA 94080 0 1 0 0 See Remarks Stock Option (Right to Buy) 9.08 2016-02-02 4 A 0 34014 A 2026-02-01 Common Stock 34014 34014 D The shares subject to this option shall vest and become exercisable in 48 equal monthly installments with the first installment on February 1, 2016, such that this option is fully exercisable on January 1, 2020. Not applicable. Vice President, Business Development and Business Operations /s/ Steven Chan, as Attorney-in-Fact 2016-02-04