Tanruprubart

First Oral Presentation of the Tanruprubart Real-World Evidence (RWE) Study by International Guillain-Barré Syndrome Outcomes Study (IGOS) Researchers Highlights Benefits over Current Standard of Care in Matched Patient Populations Poster Presentations on New Pivotal Phase 3 Analyses Underscore Tanruprubart’s Rapid and Sustained Treatment Effect and Improvement in Quality of Life Compared to Placebo BRISBANE, Calif., May 19, 2025 (GLOBE NEWSWIRE) -- 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 presented oral and poster presentations highlighting improved outcomes with tanruprubart (formerly ANX005) at the 2025 Peripheral Nerve Society (PNS) Annual Meeting being held May 17-20, 2025 in Edinburgh, UK. GBS is a neuromuscular emergency and rare autoimmune disease that affects at least 150,000 people worldwide each year, with no FDA-approved therapies. In its acute phase, GBS rapidly progresses toward severe weakness that can lead to sudden and complete paralysis, often requiring intensive care and mechanical ventilation. Tanruprubart is a first-in-kind monoclonal antibody designed to block C1q, the initiating molecule of the classical complement cascade, with a single infusion to halt ongoing neuroinflammation and nerve damage in the early phase of GBS to improve and expedite overall recovery. “These compelling clinical results presented at PNS depict how a rapid gain in muscle strength can lead to a better state of health with a single infusion of tanruprubart in a real world setting,” said Henk-André Kroon, M.D., senior vice president of Translational Medicine at Annexon. “Currently, outcomes for GBS patients around the world remain poor, and we are grateful to our collaborators at IGOS for conducting this prespecified analysis showing the significant improvement with tanruprubart compared to standard of care. As the potential first targeted immunotherapy in GBS, we are eager to move tanruprubart forward for patients in need, with the aim of transforming the global treatment landscape for GBS.” RWE Findings Demonstrate Benefits with Tanruprubart over Current Standard of Care in Matched Patient Populations Results of the pivotal Phase 3 trial are reinforced by a RWE study that matched tanruprubart-treated patients from the pivotal Phase 3 trial with patients predominantly from western countries included in the IGOS registry who were treated with current standard of care, intravenous immunoglobulin (IVIg) or plasma exchange (PE). In the RWE study, tanruprubart showed a rapid increase in muscle function resulting in a sustained and more complete recovery compared to IVIg or PE: By Week 1, patients treated with tanruprubart showed approximately a ten-point improvement in muscle strength over patients treated with IVIg or PE, a clinically meaningful benefit as measured by Medical Research Council (MRC) sumscore and an indicator for future recovery potential Patients treated with tanruprubart were approximately three times more likely to be in a better state of health than patients on IVIg or PE on the GBS-Disability Scale (GBS-DS) at Weeks 4, 8, and 26 New Pivotal Phase 3 Trial Analyses Reinforce the Rapid and Sustained Clinical Benefits of a Single Dose of Tanruprubart Tanruprubart 30 mg/kg halted inflammation and nerve damage resulting in clinical benefits as early as Week 1, including rapid improvements in muscle strength, mobility, balance, and coordination that were maintained through Week 26 Tanruprubart-treated patients rapidly regained the ability to move independently, do personal tasks, and return to a range of routine daily living activities Tanruprubart demonstrated a greater degree of efficacy amongst patients with disease characteristics more commonly observed in western countries, supporting the potential of tanruprubart to benefit patients worldwide Presentations are available on the publications page of the company’s website. About Tanruprubart (formerly ANX005) Annexon’s lead investigational therapy, tanruprubart, is a first-of-its kind selective, targeted and rapid-acting agent designed to reduce inflammation and nerve damage by stopping C1q activity in the peripheral and central nervous systems. In GBS, tanruprubart is designed to seek out C1q and prevent its binding to targets on peripheral nerves. Tanruprubart is administered intravenously and has been observed to act almost immediately in blocking C1q function. The aim of an effective treatment in GBS is to rapidly stop the autoimmune damage on nerve cells, allowing patients to regain muscle strength sooner and to regain independence and return to pre-illness activities. Tanruprubart has received both Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration as well as orphan drug designation from the European Medicines Agency for the treatment of GBS. About Guillain-Barré Syndrome (GBS) GBS is a rare neuromuscular emergency resulting from an acute autoantibody and classical complement-mediated attack on peripheral nerves that generally occurs post-infection in otherwise healthy persons. It is an acute, rapidly progressive disease with a narrow timeframe for therapeutic intervention. GBS results in the hospitalization of more than 22,000 people annually in the U.S. and Europe. In its acute phase, the peripheral nerve damage progresses rapidly, causing sudden and complete neuromuscular paralysis that can lead to significant morbidity, disability and mortality. Currently, there are no approved treatments for GBS in the U.S. The long-term disease burden associated with GBS has led to a multi-billion-dollar annual economic cost to the U.S. healthcare system alone. More information about the impact of GBS is available at MoveGBSForward.com. About Annexon Annexon Biosciences (Nasdaq: ANNX) is developing therapeutics that stop classical complement-driven neuroinflammation as first-in-kind treatments for millions of people living with serious neuroinflammatory diseases of the body, brain and eye. Our novel scientific approach focuses on C1q, the initiating molecule of classical complement’s potent inflammatory pathway that when misdirected can lead to tissue damage and loss. By targeting C1q, our immunotherapies are designed to stop this neuroinflammatory cascade in disease before it starts. Our pipeline spans three diverse therapeutic areas – autoimmune, neurodegenerative and ophthalmic diseases – and includes targeted investigational drug candidates designed to address the unmet needs of over 8 million people worldwide. Annexon’s mission is to deliver game-changing therapies to patients so that they can live their best lives. 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,” “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 ability of tanruprubart to block C1q activity in the peripheral and central nervous systems with a single infusion; the potential therapeutic benefit of tanruprubart, if approved, compared to IVIg/plasma exchange or existing therapies; the clinical and regulatory status of tanruprubart; the planned presentation of RWE at upcoming conferences; the ability to translate the results of the RWE study to a broad population of GBS patients; the impacts of the new education campaign (Move GBS Forward™); 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 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 jallaire@lifesciadvisors.com Media Contact: Sheryl Seapy Real Chemistry 949-903-4750 sseapy@realchemistry.com

FDA Meeting for Tanruprubart (formerly ANX005), the First Potential Targeted Therapy for GBS, Scheduled for Second Quarter 2025 Ahead of Planned BLA Submission Open-Label Tanruprubart FORWARD Study Designed to Broaden Patient and Healthcare Community Experience in North America and Europe, Initiating in Second Quarter 2025 Accelerated Enrollment in Phase 3 ARCHER II Trial on Pace for Completion in Third Quarter 2025 for ANX007, the First Potential Treatment for Dry AMD with GA; Pivotal Topline Data Expected in the Second Half of 2026 Completion of Proof-of-Concept Trial for First-in-Kind Oral C1s Inhibitor ANX1502 in Cold Agglutin Disease Anticipated Mid-2025; Potential to Disrupt the Current Treatment of Antibody-Mediated Autoimmune Diseases $263.7 million in Cash, Cash Equivalents, and Short-term Investments as of March 31, 2025 Funds Late-Stage Milestones for Lead Programs and Anticipated Runway into Second Half 2026 BRISBANE, Calif., May 12, 2025 (GLOBE NEWSWIRE) -- 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 first quarter 2025 financial results. “Our innovative C1 platform has yielded multiple wholly owned late-stage programs that have been shown to stop harmful neuroinflammation and lead to positive outcomes for patients across an array of diseases,” said Douglas Love, president and chief executive officer of Annexon. “Our most advanced program, tanruprubart, is approaching filing for the treatment of Guillain-Barré Syndrome (GBS) having consistently demonstrated rapid and sustained functional improvements in multiple placebo-controlled trials. Given the decades-long void of innovation, GBS remains a high unmet need without FDA-approved therapies or substantial evidence of effectiveness from the current standard of care, and we are eager to continue our dialogue with the FDA during our upcoming meeting this quarter in advance of our planned BLA submission. Furthermore, we are excited for the launch this quarter of the open-label FORWARD study designed to provide North American and European physicians and patients investigational access and experience with tanruprubart’s single infusion approach to tackling GBS.” Mr. Love continued, “Our second late-stage asset, ANX007, is poised to be the first vision-preserving treatment for dry age-related macular degeneration (AMD) with geographic atrophy (GA) globally, offering the potential to benefit more than eight million patients worldwide. With positive engagement by the retina community, we are on an accelerated pace to complete enrollment of the ongoing Phase 3 ARCHER II trial in the third quarter and deliver pivotal topline data in the second half of 2026. Finally, we anticipate completing the proof-of-concept (POC) trial for our oral small molecule ANX1502 in mid-2025, further characterizing its initial drug profile in patients with autoimmune disease.” Mr. Love concluded, “With continued strong strategic execution and runway into the second half of 2026, we are well-positioned to drive immense near to mid-term value and fulfill our mission of helping millions of patients live their best lives.” Recent Corporate and Clinical Program Updates Flagship Programs Tanruprubart (ANX005) in Guillain-Barré Syndrome (GBS): First-in-kind monoclonal antibody designed to block C1q with a single infusion to halt ongoing neuroinflammation and nerve damage in the acute phase of disease. GBS is a rare, neuromuscular emergency that affects approximately 150,000 people worldwide each year. Strong therapeutic potential underscored by consistent demonstration of rapid and durable functional improvements and a differentiated safety profile across multiple placebo-controlled clinical studies. There are no FDA-approved therapies for GBS and no substantial evidence of effectiveness from the current standards of care therapy used in GBS. The rare and acute nature of GBS has shaped our clinical development program conducted primarily in Southeast Asia to generate a comprehensive data package. This package includes successful placebo-controlled POC and Phase 3 data, Real-World Evidence indirect comparison data of tanruprubart’s treatment effect versus current standards of care, and drug-drug interaction safety data with tanruprubart with current standard of care. To further our strategic development plan, preparing to initiate the open-label tanruprubart FORWARD study, measuring pharmacokinetics, pharmacodynamics, early efficacy in week 1, and safety in up to 30 subjects in the United States, Canada, and Europe, which is designed to broaden Western patient, physician and healthcare community experience. Real-World Evidence study to be featured in an oral presentation on Monday May 19, 2025 at the upcoming 2025 Peripheral Nerve Society (PNS) Annual Meeting taking place May 17-20, 2025 in Edinburgh, UK. Additional poster presentations will also reinforce early and durable benefits of tanruprubart including improvement in quality of life for patients with GBS. Next Milestone: Initiation of the tanruprubart FORWARD study expected in the second quarter of 2025. FDA meeting with the Center for Drug Evaluation and Research (CDER) scheduled for the second quarter of 2025 ahead of planned BLA submission. ANX007 in Dry Age-Related Macular Degeneration (AMD) Patients with Geographic Atrophy (GA): First-in-kind, non-pegylated antigen-binding fragment (Fab) designed to block C1q and the classical complement cascade locally in the eye. Dry AMD with GA is a leading cause of blindness that affects more than eight million patients worldwide with no approved therapies targeting the preservation of vision. Global registration path established with U.S. and European regulators supports potential of ANX007 to be the first treatment approved in both Europe and the U.S. for protection of vision in patients who have dry AMD with GA. ARCHER II is a global, pivotal, sham-controlled, double-masked Phase 3 trial expected to enroll approximately 630 patients who have dry AMD with GA. Phase 2 ARCHER data showing significant preservation of vision and central retinal photoreceptors necessary for visual acuity presented at the 2025 Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting and at the 2025 Retina World Congress. Next Milestone: Phase 3 ARCHER II trial enrollment expected to be completed in third quarter of 2025; top line data expected in second half of 2026. ANX1502 for Autoimmune Conditions: First-in-kind oral small molecule inhibiting the activated form of C1s, an enzyme carried by C1q to initiate the classical cascade, has the potential to offer the advantages of selective upstream classical complement inhibition with the convenience and flexibility of oral administration. Ongoing enrollment in open-label, single arm, proof-of-concept study characterizing the pharmacokinetics, pharmacodynamics, dosing regimen, safety and initial efficacy of enteric-coated tablets of ANX1502 in up to seven patients with cold agglutinin disease (CAD). Next Milestone: POC trial completion in up to seven CAD patients anticipated in mid-2025. First Quarter 2025 Financial Results Cash and operating runway: Cash and cash equivalents and short-term investments were $263.7 million as of March 31, 2025. Annexon continues to expect its cash, cash equivalents and short-term investments as of March 31, 2025, to be sufficient to fund the company’s planned operating expenses and late-stage milestones for its lead programs into the second half of 2026. Research and development (R&D) expenses: R&D expenses were $48.2 million for the quarter ended March 31, 2025, reflecting the advancement of the Company’s priority programs, including GBS, GA and ANX1502, compared to $21.0 million for the quarter ended March 31, 2024. General and administrative (G&A) expenses: G&A expenses were $9.2 million for the quarter ended March 31, 2025, compared to $7.6 million for the quarter ended March 31, 2024. Net loss: Net loss was $54.4 million or $0.37 per share for the quarter ended March 31, 2025, compared to $25.2 million or $0.21 per share for the quarter ended March 31, 2024. About Annexon Annexon Biosciences (Nasdaq: ANNX) is developing therapeutics that stop classical complement-driven neuroinflammation as first-in-kind treatments for millions of people living with serious neuroinflammatory diseases of the body, brain and eye. Our novel scientific approach focuses on C1q, the initiating molecule of classical complement’s potent inflammatory pathway that when misdirected can lead to tissue damage and loss in a host of diseases. By targeting C1q, our immunotherapies are designed to stop this neuroinflammatory cascade before it starts. Our pipeline spans three diverse therapeutic areas – autoimmunity, neurodegeneration and ophthalmology – and includes targeted investigational drug candidates designed to address the unmet needs of nearly 10 million people worldwide. Annexon’s mission is to deliver game-changing therapies to patients so that they can live their best lives. 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 potential therapeutic benefit of ANX005, if approved, compared to existing therapies; anticipated timing of the pre-BLA meeting and BLA submission for ANX005; potential benefit of ANX005, if approved, compared to existing therapies; the design, objectives and timing of the open-label tanruprubart FORWARD study; the company’s ability to achieve regulatory approval for ANX005; the potential therapeutic benefit of ANX007; timing and pace of completion of enrollment and results from the Phase 3 ARCHER II trial; ANX007’s distinct potential neuroprotective mechanism of action and potential to provide protection from vision loss; the potential for ANX007 to be the first drug approved in Europe and the U.S. for dry AMD with GA; timing of proof-of-concept trial for ANX1502 in cold agglutin disease; the potential for ANX1502 to disrupt the current treatment antibody-mediated autoimmune diseases; the company’s ability to commercialize its product candidates, if approved; 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 final results from the Phase 3 ARCHER II 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 jallaire@lifesciadvisors.com Media Contact: Sheryl Seapy Real Chemistry 949-903-4750 sseapy@realchemistry.com