X0206 3 2015-10-28 0 0001552451 MyoKardia Inc MYOK 0001468345 TOPOL ERIC C/O MYOKARDIA, INC. 333 ALLERTON AVENUE SOUTH SAN FRANCISCO CA 94080 1 0 0 0 Stock Option (Right to Buy) 4.05 2025-09-16 Common Stock 21768 D Stock Option (Right to Buy) 4.05 2025-09-16 Common Stock 21768 D The shares subject to this option shall vest and become exercisable in 48 equal monthly installments with the first installment on October 17, 2015, such that this option is fully exercisable on September 17, 2019. Exhibit List: Exhibit 24.1 - Power of Attorney /s/ Steven Chan, attorney-in-fact 2015-10-28