Zymeworks Inc

On July 29, 2024, we notified Cantor of our decision to terminate the Sales Agreement effective July 31, 2024. The Sales Agreement provided for the offer and sale of our common stock from time to time through Cantor as our sales agent, subject to the maximum aggregate dollar amount registered pursuant to the applicable prospectus supplement. Sales of shares of common stock through Cantor were to be made by any method permitted by law deemed to be an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act, including without limitation sales made directly on the Nasdaq or any other existing trading market for our common stock. An aggregate of 3,350,000 shares of common stock were sold under the Sales Agreement.

The foregoing description of the Sales Agreement is not complete and is qualified in its entirety by reference to the full text of the Sales Agreement, a copy of which is filed as Exhibit 10.53 to our Annual Report on Form 10-K filed with the SEC on March 6, 2024.

During our last fiscal quarter, no director or officer, as defined in Rule 16a-1(f) of the Exchange Act, adopted orterminated a “Rule 10b5-1 trading arrangement” or any “non-Rule 10b5-1 trading arrangement,” each as defined in Item 408 of Regulation S-K.