Annexon Reports Second Quarter 2024 Portfolio and Financial Results, and Key Anticipated Milestones Form 8 K

Annexon Reports Second Quarter 2024 Portfolio and Financial Results, and Key Anticipated Milestones

Single, Well-Tolerated Infusion of ANX005 Significantly Accelerated Recovery of GBS Patients vs. Placebo in Pivotal Phase 3 Trial; Potential to be First Targeted Therapy for GBS; Topline Real-World Evidence (RWE) Comparability Data Now Expected by Year-End 2024

Dosing Initiated in ARCHER II Registrational Trial for ANX007; Only Program to Demonstrate Significant Vision Protection and Structural Protection in Regions of the Eye Important for Vision Acuity in GA; Phase 3 Data Expected Second Half 2026

First-in-Kind Oral C1s Inhibitor ANX1502 Successfully Completed Bridging Study to Twice-Daily Tablet; Proof-of-Concept Data in Autoimmune Disease Expected Q4 2024

Robust Balance Sheet with Cash, Cash Equivalents, and Short-term Investments of Approximately $368.7 Million as of June 30, 2024, and Anticipated Runway into Second Half 2026

BRISBANE, Calif., August 12, 2024 - Annexon, Inc. (Nasdaq: ANNX), a biopharmaceutical company advancing a late-stage clinical platform of novel therapies for people living with devastating classical complement-mediated neuroinflammatory diseases of the body, brain, and eye, today highlighted portfolio progress and reported second quarter 2024 financial results.

"Annexon is at the cross section where decades of pioneering research and development are translating into clinical wins for scores of patients. This was exemplified in the first half of 2024 by the robust functional and biomarker data from two of our flagship programs: Guillain-Barré syndrome (GBS) and geographic atrophy (GA). These data further highlight the powerful disease modifying potential of our platform approach by blocking neuroinflammation where it starts in diverse acute and chronic conditions of high unmet need," said Douglas Love, president and chief executive officer of Annexon. "In that regard, ANX005 helped GBS patients suffering from an acute neuromuscular emergency get better sooner and more completely in the first placebo-controlled pivotal study in 40 years. Moreover, ANX007 is the only program shown to help GA patients significantly preserve their vision while protecting associated retina structures critical for vision. We're also pleased to report that the bridging study for our oral inhibitor ANX1502, the first clinical stage oral inhibitor of the classical pathway, has completed and the safety and pharmacokinetics profile confirmed the findings from the healthy volunteer trial."

Mr. Love continued, "With these data, we're actively working to build on our strong momentum across our flagship programs with several key catalysts over the next 24-months that have the potential to drive significant benefit for millions of patients and our shareholders. Importantly, we now expect earlier topline data by year-end 2024 for our real-world evidence comparability study for ANX005 in GBS to support our BLA submission targeted for the first half of 2025. Additionally, our ~630 patient potentially best-in-disease global Phase 3 GA program has been initiated, and we anticipate pivotal data in the second half of 2026. Lastly, we remain on pace for proof-of-concept data for ANX1502 in Cold Agglutinin Disease (CAD)in the latter part of the year, which has the potential to enable advancement in an array of autoimmune indications. With a strong cash position, we are more excited than ever and remain sharply focused on delivering multiple first-in-kind targeted therapies to improve the lives of millions of patients living with devastating neuroinflammatory diseases."

Recent Clinical Program Updates

Flagship Programs

ANX005 in Guillain-Barré syndrome (GBS): First-in-kind monoclonal antibody designed to block C1q and the entire classical complement pathway in both the body and the brain.

ANX007 in Geographic Atrophy (GA): First-in-kind, non-pegylated antigen-binding fragment (Fab) designed to block C1q and activation of the classical complement cascade locally in the eye with an intravitreal formulation.

ANX1502 for Autoimmune Conditions: First-in-kind oral small molecule inhibitor of the classical complement pathway designed to target chronic autoimmune diseases.

Key Anticipated Milestones for Flagship Programs

Second Quarter 2024 Financial Results

About Annexon

Annexon Biosciences (Nasdaq: ANNX) is a biopharmaceutical company advancing a late-stage clinical platform of novel therapies for people living with devastating classical complement-mediated neuroinflammatory diseases of the body, brain, and eye. Annexon's novel scientific approach targets upstream C1q to block the classical complement inflammatory cascade before it starts, and its therapeutic candidates are designed to provide meaningful benefits across multiple autoimmune, neurodegenerative and ophthalmic diseases. With proof-of concept data in Guillain-Barré syndrome, Huntington's disease and geographic atrophy, Annexon is rigorously advancing its mid-to late-stage clinical trials to bring new potential treatments to patients as quickly as possible. To learn more visit annexonbio.com.

Forward Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. In some cases, you can identify forward-looking statements by terminology such as "aim," "anticipate," "assume," "believe," "contemplate," "continue," "could," "design," "due," "estimate," "expect," "goal," "intend," "may," "objective," "plan," "positioned," "potential," "predict," "seek," "should," "target," "will," "would" and other similar expressions that are predictions of or indicate future events and future trends, or the negative of these terms or other comparable terminology. All statements other than statements of historical facts contained in this press release are forward-looking statements. These forward-looking statements include, but are not limited to, statements about: the timing of completion of Phase 3 trial of ANX005 in patients with GBS; the potential therapeutic benefit of ANX005, if approved, compared to existing therapies; anticipated timing of the completion of a RWE comparability study and BLA submission for ANX005; the potential therapeutic benefit of ANX007; timing of the ARCHER II trial and initiation of ARROW trial; ANX007's distinct potential neuroprotective mechanism of action and potential to provide protection from vision loss; timing of proof-of-concept data for ANX1502; continued development of ANX007 and ANX1502; anticipated cash runway into the second half of 2026; the potential benefits from treatment with anti-C1q therapy; and continuing advancement of the company's portfolio. Forward-looking statements are not guarantees of future performance and are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated, including, but not limited to, risks and uncertainties related to: the ongoing off-treatment follow-up portion of the ARCHER trial and final results from the ARCHER trial; the company's history of net operating losses; the company's ability to obtain necessary capital to fund its clinical programs; the early stages of clinical development of the company's product candidates; the effects of public health crises on the company's clinical programs and business operations; the company's ability to obtain regulatory approval of and successfully commercialize its product candidates; any undesirable side effects or other properties of the company's product candidates; the company's reliance on third-party suppliers and manufacturers; the outcomes of any future collaboration agreements; and the company's ability to adequately maintain intellectual property rights for its product candidates. These and other risks are described in greater detail under the section titled "Risk Factors" contained in the company's Annual Report on Form 10-K and Quarterly Reports on Form 10-Q and the company's other filings with the SEC. Any forward-looking statements that the company makes in this press release are made pursuant to the Private Securities Litigation Reform Act of 1995, as amended, and speak only as of the date of this press release. Except as required by law, the company undertakes no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Contact:

Joyce Allaire

LifeSci Advisors

[email protected]

Media Contact:

Sheryl Seapy

Real Chemistry

949-903-4750

[email protected]

ANNEXON, INC.

Condensed Consolidated Statements of Operations

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(unaudited)

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ANNEXON, INC.

Condensed Consolidated Balance Sheets

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