ANNX

EX-99.1

2 d119960dex991.htm

EX-99.1

EX-99.1

Exhibit 99.1

Annexon Reports Second Quarter 2026 Financial Results, Business Updates and Key Anticipated Milestones

Rapid, Positive Clinical Outcomes in GBS FORWARD Study Reinforce Consistency and Reproducibility of Tanruprubart Treatment Effect Demonstrated in Phase 3 and Real-World Evidence Studies; BLA Submission Expected in Q4 2026

Vonaprument Phase 3 GA Program Expanded with Month 15 / 24 Dual Primary Endpoint Strategy and Launch of Open-Label Extension Study; Month 15 Primary Endpoint on Track for Q4 2026

POC Data for ANX1502, a First-in-Kind Oral C1 Inhibitor for Autoimmune Disease, Expected in Fall 2026

$200 Million Credit Facility Strengthens Balance Sheet and Capabilities; Anticipated Runway Extended into 2028

Company to Host Business Update Call Today at 8:00 a.m. ET

BRISBANE, Calif., August 12, 2026 – Annexon, Inc. (Nasdaq: ANNX), a biopharmaceutical company advancing the next generation platform of targeted immunotherapies aimed at neuroinflammatory diseases that impact nearly 10 million people worldwide, today highlighted portfolio progress, announced key anticipated milestones, and reported second quarter 2026 financial results. The Company will host a business update call today at 8:00 a.m. ET to discuss corporate and clinical developments across its C1q-focused neuroinflammatory pipeline. Please register for the event here.

“2026 is a defining year for our company, with meaningful progress across both our Guillain-Barré syndrome (GBS) and geographic atrophy (GA) programs that position us to potentially deliver two transformative therapies for millions of patients in need. The quality and consistency of the data generated to date reinforce our confidence in the differentiated potential of our C1q-targeted approaches to address neuroinflammatory diseases at their source, and we are encouraged by the growing enthusiasm from patients and physicians,” said Douglas Love, president and chief executive officer of Annexon. “With our leadership capabilities and financial position strengthened, we are entering an exciting period of execution, with multiple important clinical and regulatory milestones expected over the next 6 to 12 months and a significant opportunity to create value for patients and stakeholders.”

2026 Strategic Priorities and Key Milestones

Tanruprubart: Potential to be the first targeted, fast-acting therapy for GBS, an indiscriminate life-threatening neuromuscular emergency affecting 150,000 people annually worldwide and driving an estimated $20+ billion annual healthcare burden in the U.S.

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Early improvement in strength and clinically meaningful reduction in disability shown with tanruprubart in the first ten U.S. and European patients with GBS from the ongoing, open-label FORWARD study. Early outcomes reinforce the consistency and reproducibility of tanruprubart treatment effect previously demonstrated in Phase 3 and real-world evidence studies.

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EU Marketing Authorisation Application under review with the European Medicines Agency supported by robust data package demonstrating rapid benefit on function and disability in placebo-controlled studies and Real-World Evidence study demonstrating favorable outcomes versus current treatments, intravenous immunoglobulin and plasma exchange.

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Next Milestone: Biologics License Application (BLA) submission with U.S./European data from FORWARD trial expected in fourth quarter of 2026.

Vonaprument: Potential to be the first targeted vision-preserving therapy for GA, a leading cause of blindness affecting more than 8 million patients worldwide.

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The ongoing, global, double masked Phase 3 ARCHER II trial remains on track, and all eligible patients have received at least 12 months of treatment, with masked event accrual consistent with projected timelines. Vonaprument continues to be generally well-tolerated with a low discontinuation rate (<10%) and high compliance (>95%), reinforcing significant enthusiasm by physicians/patients.

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To maximize the best-in-class potential of vonaprument, a Month 24 dual primary endpoint was added while maintaining the Month 15 primary endpoint. This strategic enhancement was enabled by the strong power and execution of the Phase 3 ARCHER II trial. With a dual primary endpoint strategy, ARCHER II can achieve success in protecting against vision loss at either Month 15 or 24, which are independent efficacy timepoints.

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Annexon also launched an open-label extension (OLE) study to evaluate the the long-term safety and benefit of

vonaprument in patients with GA. Following completion of the 2-year ARCHER II study, all patients have the option to receive monthly vonaprument treatment in the OLE study.

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Next Milestones: Month 15 primary endpoint on track for the fourth quarter of 2026, with final trial completion, including the Month 24 primary endpoint expected in the third quarter of 2027.

ANX1502 for Autoimmune Conditions: First-in-kind or

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