X0306 4 2020-01-01 0 0001552451 MyoKardia Inc MYOK 0001654909 Bauer Jake C/O MYOKARDIA, INC. 333 ALLERTON AVENUE SOUTH SAN FRANCISCO CA 94080 0 1 0 0 Chief Business Officer Common Stock 2020-01-01 4 M 0 6375 A 49957 D Restricted Stock Units 2020-01-01 4 M 0 1425 0.00 D Common Stock 1425 2850 D Restricted Stock Units 2020-01-01 4 M 0 4950 0.00 D Common Stock 4950 14850 D Restricted stock units convert into common stock on a one-for-one basis. Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Issuer's Common Stock. The shares of Common Stock underlying the RSUs vest in equal annual installments over 4 years from January 1, 2018, so that all of the underlying shares shall be vested on January 1, 2022, subject to the Reporting Person's continued employment with the Issuer through each vesting date. The RSUs are subject to accelerated vesting upon termination without cause after a change of control of the Issuer. Each RSU represents a contingent right to receive one share of Issuer's Common Stock. The shares of Common Stock underlying the RSUs vest in equal annual installments over 4 years from January 1, 2019, so that all of the underlying shares shall be vested on January 1, 2023, subject to the Reporting Person's continued employment with the Issuer through each vesting date. The RSUs are subject to accelerated vesting upon termination without cause after a change of control of the Issuer. /s/ Cynthia J. Ladd, as Attorney-in-Fact 2020-01-03