X0306 4 2019-05-06 0 0001403752 Zymeworks Inc. ZYME 0001761857 Klompas Neil A C/O ZYMEWORKS INC. 1385 WEST 8TH AVENUE, SUITE 540 VANCOUVER A1 V6H 3V9 BRITISH COLUMBIA, CANADA 0 1 0 0 Chief Financial Officer Common Stock 2019-05-06 4 M 0 6704 2.66 A 7905 D Common Stock 2019-05-06 4 S 0 6704 19.2206 D 1201 D Common Stock 2019-05-06 4 M 0 8380 3.53 A 9581 D Common Stock 2019-05-06 4 S 0 1604 19.2506 D 7977 D Common Stock 700 I Held by spouse Stock Option (Right to Buy) 2.66 2019-05-06 4 M 0 6704 0.00 D 2008-07-01 2019-07-01 Common Shares 6704 0 D Stock Option (Right to Buy) 3.53 2019-05-06 4 M 0 8380 0.00 D 2010-07-01 2019-06-30 Common Shares 8380 0 D The exercise price of the stock option is CAD3.58. The U.S. dollar equivalent of the exercise price is $2.66 using the Bank of Canada exchange rate for May 6, 2019 (CAD1.00 = $0.7432). The shares were sold in multiple transactions and the price reported is a weighted average. The sale prices ranged from $19.07 to $19.48. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The exercise price of the stock option is CAD4.75. The U.S. dollar equivalent of the exercise price is $3.53 using the Bank of Canada exchange rate for May 6, 2019 (CAD1.00 = $0.7432). The shares were sold in multiple transactions and the price reported is a weighted average. The sale prices ranged from $19.13 to $19.365. The reporting person undertakes to provide the issuer, any security holder of the issuer, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. Stock options vest as follows: (i) 25% of underlying shares on first anniversary of grant date of July 1, 2007, and (ii) remainder of underlying shares in 36 equal monthly installments on last day of month following first anniversary of grant date. Stock options vest as follows: (i) 25% of underlying shares on first anniversary of grant date of July 1, 2009, and (ii) remainder of underlying shares in 36 equal monthly installments on last day of month following first anniversary of grant date. /s/ Daniel Dex, Attorney-in-Fact 2019-05-08