Results of Operations and Financial Condition. On August 10, 2026, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended June 30, 2026. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Entry into a Material Definitive Agreement. On July 2, 2026, Enanta Pharmaceuticals, Inc. (the “Corporation”) entered into an Open Market Sale Agreement SM (the “Sales Agreement”) with Jefferies LLC, as sales agent (the “Agent”), pursuant to which the Corporation may offer and sell shares (the “Shares”) of its common stock, $0.01 par value per share (“Common Stock”), from time to time through the Agent. The Common Stock is being offered and sold pursuant to the Corporation’s previously filed…

Results of Operations and Financial Condition. On May 11, 2026, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended March 31, 2026. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

The filing is about an equity plan amendment, not a management change.

Results of Operations and Financial Condition. On February 9, 2026, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended December 31, 2025. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On November 17, 2025, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter and year ended September 30, 2025. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Other Events. Public Offering On September 30, 2025, Enanta Pharmaceuticals, Inc. (“Enanta”) entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC, Jefferies LLC, and Evercore Group L.L.C., as representatives of the several underwriters named therein (collectively, the “Underwriters”), relating to the issuance and sale in a public offering of 6,500,000 shares of Enanta’s common stock, par value $0.01 per share (the “Common Stock”). The price to…

interim principal financial officer and interim principal accounting officer — Harry R. Trout, III and Kathleen ('Katie') S. Capps, CPA: Paul J. Mellett is on a medical leave of absence.

Other Events. On August 20, 2025, Enanta announced that it filed suit in the UPC of the European Union against Pfizer Inc. and certain of its subsidiaries (action number 35071/2025), seeking a determination of liability for use and infringement of European Patent No. EP 4 051 265 (the ’265 Patent) in the manufacture, use and sale of Pfizer’s COVID-19 antiviral, Paxlovid™ (nirmatrelvir tablets; ritonavir tablets). This enforcement action targets Pfizer’s activities in the 18 countries of the E…

Results of Operations and Financial Condition. On August 11, 2025, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended June 30, 2025. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On May 12, 2025, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended March 31, 2025. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

The filing is about an equity plan amendment, not a management change.

Results of Operations and Financial Condition. On February 10, 2025, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended December 31, 2024. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

above, Enanta announced positive topline data from its Phase 2 pediatric study of zelicapavir for the treatment of RSV on December 9, 2024. This Phase 2 study was a randomized, double-blind, dose ranging, placebo-controlled study in hospitalized and non-hospitalized pediatric patients with RSV aged 28 days to 36 months. The primary objective of Part 1 of the study was to evaluate the safety and pharmacokinetics of zelicapavir and to determine the optimal dosing for Part 2 of the study. The pr…

Results of Operations and Financial Condition. On November 25, 2024, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter and year-ended September 30, 2024. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On August 5, 2024, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended June 30, 2024. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On May 6, 2024, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended March 31, 2024. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

The filing is about an equity plan amendment, not a management change.

Results of Operations and Financial Condition. On February 7, 2024, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended December 31, 2023. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Senior Vice President and General Counsel — Nathaniel S. Gardiner: Senior Vice President and General Counsel announced his intention to retire.

Results of Operations and Financial Condition. On November 20, 2023, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter and year ended September 30, 2023. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On August 7, 2023, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter June 30, 2023. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Results of Operations and Financial Condition. On May 8, 2023, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter March 31, 2023. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.

Entry into a Material Definitive Agreement. On April 25, 2023, Enanta Pharmaceuticals, Inc. and OCM Life Sciences Portfolio LP, an investment vehicle of OMERS, one of Canada’s largest defined benefit pension plans, entered into a Royalty Purchase Agreement (the “ Agreement ”), pursuant to which Enanta sold to OMERS 54.5% of Enanta’s royalty interest in respect of worldwide net sales of MAVYRET ® /MAVIRET ® (and any other royalty-bearing products that may contain glecaprevir). The purchase pri…

Results of Operations and Financial Condition. On February 7, 2023, Enanta Pharmaceuticals, Inc. announced via press release its results for the fiscal quarter ended December 31, 2022. A copy of Enanta's press release is hereby furnished to the Commission and incorporated by reference herein as Exhibit 99.1.