144 0001233539 XXXXXXXX LIVE 0001937653 Zymeworks Inc. 001-41535 108 Patriot Drive Suite A Middletown DE 19709 302-274-8744 Leone D Patterson Former officer Common Stock Morgan Stanley Wealth Management Canada

140 4th Ave. SW, Suite 2740 Calgary A0 T2P 3N3

6832 158297.44 74836534 01/12/2026 Nasdaq Common Stock 01/12/2026 Vesting of Restricted Stock Units Issuer N 17666 01/12/2026 Vesting of Award Y The shares of common stock to be sold represent shares to be sold to cover tax withholding obligations and other fees in connection with the vesting of RSUs pursuant to mandatory "sell to cover" provisions contained in the applicable RSU grant agreement. 01/12/2026 /s/ Leone D Patterson