Phathom Pharmaceuticals, Inc.

There have been no material changes to the risk factors disclosed in Part I, Item 1A, “Risk Factors” of our 2025 Form 10-K, other than as set forth below.

An adverse outcome in litigation challenging FDA's recognition of GAIN Act-extended NCE exclusivity for VOQUEZNA tablets, or in related FDA proceedings, could result in earlier generic competition than expected and adversely affect our business.

As previously disclosed, in June 2025, the FDA granted our Citizen Petition and updated the Orange Book to reflect NCE exclusivity for VOQUEZNA (vonoprazan) tablets through May 3, 2032, based on the extension provided under the GAIN Act. All three of our VOQUEZNA products have NCE exclusivity through that date. Subject to certain exceptions, including for ANDAs containing Paragraph IV patent certifications beginning one year earlier, the FDA generally may not receive an abbreviated new drug application, or ANDA, referencing VOQUEZNA tablets during this exclusivity period.

In October 2026, BDR Pharmaceuticals International Pvt. Ltd., or BDR, filed a lawsuit against the FDA and related federal defendants challenging the FDA's application of the GAIN Act to extend NCE exclusivity for VOQUEZNA tablets and its alleged refusal to receive BDR's ANDA. We have intervened in the litigation to defend our statutory exclusivities. Another purported ANDA filer, Saba Ilac Sanayii Ve Ticaret AS, or Saba, has indicated that it intends to seek consolidation of a related case with BDR's litigation. Other parties may bring similar challenges or seek to participate in or benefit from the litigation. In connection with the litigation, the FDA has opened a public docket seeking comments by November 23, 2026 on related legal and regulatory questions. Members of the public may submit comments in a manner adverse to our position, and those comments may influence FDA's decision.

We believe the FDA correctly determined VOQUEZNA's exclusivity, but there can be no assurance that the FDA will maintain its determination or that a court will uphold it. An adverse outcome could shorten VOQUEZNA tablets' regulatory exclusivity, permit earlier submission and potential approval of ANDAs, and result in generic competition sooner than expected. Our ability to prevent or delay generic competition would then depend more heavily on our patents, which may be challenged or circumvented, and could require additional patent litigation. Earlier generic competition could materially reduce VOQUEZNA's sales, pricing and market share and adversely affect our business, financial condition, results of operations and prospects.

The litigation and related proceedings may be lengthy, costly and distracting to management, and their outcomes are uncertain. Developments in these matters, or perceptions regarding their potential impact on VOQUEZNA's exclusivity, could adversely affect our stock price, commercial performance and business, even if the FDA's determination is ultimately upheld.