144 0001915257 XXXXXXXX LIVE 0001937653 Zymeworks Inc. 001-41535 108 Patriot Drive Suite A Middletown DE 19709 302-274-8744 Christopher Astle Former Officer Common Stock Morgan Stanley

1585 Broadway New York NY 10036

86294 774057.18 70704890 06/11/2024 Nasdaq Common Stock 01/07/2022 Purchased pursuant to Employee Stock Purchase Plan Issuer N 670 01/07/2022 Cash payment pursuant to Employee Stock Purchase Plan Common Stock 12/12/2022 Acquired as compensation - Restricted Stock Units Issuer N 663 12/12/2022 Compensation Common Stock 12/11/2023 Acquired as compensation - Restricted Stock Units Issuer N 664 12/11/2023 Compensation Common Stock 01/05/2024 Acquired as compensation - Restricted Stock Units Issuer N 4506 01/05/2024 Compensation Common Stock 06/11/2024 Exercise of options Issuer N 79791 06/11/2024 Exercise and sell to cover Y 06/11/2024 /s/ Christopher Astle