Zymeworks (ZYME) SEC Filings, Jun-Nov 2025

Zymeworks Inc. has decided to voluntarily discontinue clinical development of ZW171, a T cell engager targeting gynecological, thoracic, and digestive system cancers. The decision follows completion of the planned dose-escalation cohorts in a Phase 1 trial in patients with ovarian cancer and non-small cell lung cancer, where a maximum tolerated dose was established. After reviewing these results, the company concluded that further dose evaluation in the current trial was unlikely to support a benefit-risk profile consistent with the desired monotherapy target product profile. The decision was announced via press release furnished as an exhibit.

Zymeworks Inc. (ZYME) Schedule 13G/A reports that Redmile Group, LLC and its principal Jeremy C. Green each have shared voting and dispositive power over 4,150,627 shares of Zymeworks common stock, representing 5.6% of the class based on 74,844,505 shares outstanding as of June 27, 2025. One Redmile vehicle, Redmile Biopharma Investments III, L.P., holds 3,470,727 shares ( 4.6%). The filers state the shares are held by Redmile-managed private investment vehicles, that Redmile and Mr. Green may be deemed beneficial owners solely as manager/principal, and they disclaim beneficial ownership except to the extent of any pecuniary interest. The filing certifies the securities were acquired and are held in the ordinary course of business and not to change or influence control.

Gregory Austin Ciongoli, a director of Zymeworks Inc. (ZYME), reported acquisitions of company securities in August 2025. The Form 4 shows he acquired 415,000 shares of common stock on 08/12/2025 at a price of $12.02, bringing his reported direct beneficial ownership to 488,500 shares.

The filing also discloses an indirect holding of 5,000 shares held by 4 Arrows Holdings, LLC, for which he is manager, and a grant of 62,000 stock options on 08/11/2025 with an exercise price of $12.44. The options vest in 36 equal monthly installments beginning one month after the grant date and show an expiration date of 08/10/2035. The Form 4 was signed by an attorney-in-fact on 08/12/2025.

Robert E. Landry, a director of Zymeworks Inc. (ZYME), was granted stock options on 08/11/2025. The award consists of options to purchase 62,000 shares of common stock at an exercise price of $12.44 per share, with an expiration date of 08/10/2035. The options vest in 36 equal monthly installments beginning one month after the grant date. Following the reported transaction, Mr. Landry directly beneficially owns 62,000 option units.

Zymeworks Inc. director Robert E. Landry filed an initial Form 3 reporting that he does not beneficially own any shares or derivative securities of the company. The filing identifies Mr. Landry as a director and indicates the submission covers a single reporting person. No transactions, grants, or indirect ownership arrangements are disclosed in the form.

Zymeworks director Gregory Austin Ciongoli filed an initial Form 3 reporting beneficial ownership in the issuer. He directly owns 73,500 shares of common stock and, as manager of 4 Arrows Holdings, LLC, exercises sole voting and dispositive power over an additional 5,000 shares while disclaiming beneficial ownership except for his pecuniary interest. The Form 3 lists the event date as 08/10/2025 and includes a signature by an attorney-in-fact dated 08/12/2025.

Zymeworks Inc. appointed Gregory A. Ciongoli and Robert E. Landry to its board effective August 10, 2025; Mr. Ciongoli was named a Class II director with a term expiring at the 2026 annual meeting and Mr. Landry was named a Class I director with a term expiring at the 2025 annual meeting. Both were added to the Audit Committee and will receive the companys standard non-employee director compensation, including an initial stock option grant to purchase 62,000 shares each.

Separately, the company entered into a private placement under which Mr. Ciongoli agreed to buy 415,000 shares at $12.02 per share for an aggregate purchase price of $4,988,300; closing is expected on or about August 12, 2025 and proceeds are intended for working capital and general corporate purposes. Troy M. Cox resigned from the board effective August 9, 2025, and the company stated the resignation was not due to any disagreement with the company.

EcoR1 Capital, LLC and affiliates have filed a Schedule 13D disclosing a 30.7% beneficial stake in Zymeworks Inc. (NASDAQ: ZYME). The group, which includes EcoR1 Capital Fund Qualified, L.P. and EcoR1 founder Oleg Nodelman, now controls 22,970,388 common shares following the recent exercise of pre-funded warrants. The ownership percentage is based on 74,844,505 shares outstanding as reported in Zymeworks’ Form 8-K dated 27 Jun 2025.

Capital deployed. EcoR1 funds have invested a cumulative $205.7 million in ZYME equity: $192.9 million by the Qualified Fund and $12.9 million by EcoR1 Capital Fund, L.P. The totals include $50.0 million used on 26 Dec 2023 to acquire pre-funded warrants that have since been exercised.

Governance influence. Oleg Nodelman and EcoR1 employee Scott Platshon already sit on Zymeworks’ board, giving the investor direct insight and influence over corporate strategy. The filing states that the shares were acquired for investment purposes and that no specific plans under Items 4(a)-(j) of Schedule 13D are currently contemplated; however, EcoR1 reserves the right to buy or sell additional shares, engage in hedging, or discuss strategic matters with management and other shareholders.

Key takeaways for investors:

• EcoR1 is now Zymeworks’ largest known holder, with voting and dispositive power shared among its entities.
• The stake underscores EcoR1’s conviction that ZYME was undervalued at the time of purchase.
• While the filing is not overtly activist, EcoR1’s 30%-plus position and board presence could accelerate strategic initiatives or heighten takeover speculation.
• Potential share-price volatility may arise if EcoR1 materially increases or reduces its position.