Frazier Life Sciences Public Fund, L.P. and related entities filed Amendment No. 12 to a Schedule 13D with the SEC on November 2, 2026, disclosing updated beneficial ownership positions in Phathom Pharmaceuticals, Inc. as of the triggering event date of October 29, 2026.

Key Highlights

  • Triggering event date: October 29, 2026, as stated in the filing.
  • Frazier Life Sciences Public Fund stake: 5,323,356 shares of common stock, representing 6.5% of the class, with shared voting and dispositive power only.
  • Frazier Life Sciences XI, L.P. position: 980,286 shares, representing 1.2% of the class, also held with shared power only.
  • Frazier Life Sciences X, L.P. position: 59,403 shares, representing 0.1% of the class.
  • Share base for percentage calculations: 81,291,520 shares of Phathom Pharmaceuticals common stock outstanding as of October 27, 2026.
  • Warrants excluded: The share counts reported for several entities do not include any warrants held by those reporting persons, according to the filing.

Frazier Life Sciences Entities Report Shared Control Over Phathom Shares

The amended Schedule 13D covers multiple Frazier-affiliated reporting persons, each organized in Delaware, including limited partnerships and limited liability companies that serve as general partner entities. According to the filing, none of the reporting persons hold sole voting or sole dispositive power over any shares; all reported positions reflect shared voting power and shared dispositive power only. Phathom Pharmaceuticals, Inc. is a pharmaceutical company whose common stock carries a par value of $0.0001 per share and trades under CUSIP 71722W107.

The filing identifies three primary fund-level positions across the Frazier group. Frazier Life Sciences Public Fund, L.P. and its associated general partner entities, FHMLSP, L.P. and FHMLSP, L.L.C., each report beneficial ownership of 5,323,356 shares at 6.5% of the class. Frazier Life Sciences XI, L.P. and its associated general partner entities report 980,286 shares at 1.2%. Frazier Life Sciences X, L.P. and its associated general partner entities report 59,403 shares at 0.1%. The filing notes that the warrants held by certain reporting persons are excluded from all share counts and directs readers to Item 5(a) of the Schedule 13D for additional detail.

The percentage figures for all reporting persons are calculated against the 81,291,520 shares outstanding as of October 27, 2026, a figure that the filing states was drawn from Phathom Pharmaceuticals' quarterly report filed with the SEC on October 29, 2026. Jennifer Martin, located at 1700 Seventh Ave, Suite 1120, Seattle, WA 98101, is identified as the person authorized to receive notices and communications on behalf of the reporting persons. The source of funds is listed as "WC" (working capital) for the primary fund-level entities and "AF" (affiliated funds) for the general partner entities.

What Was Disclosed

This amendment updated the Schedule 13D beneficial ownership positions held by multiple Frazier Life Sciences entities in Phathom Pharmaceuticals, Inc., covering three distinct fund-level groups with aggregate share counts and percentage stakes calculated against an outstanding share count of 81,291,520 as of October 27, 2026.