Annexon, Inc. · NASDAQ:ANNX

Annexon — American Academy of Neurology Annual Meeting 2025

14 slides from Annexon's conference presentation, April 2025

1. Slide 1: GBS-02: A Phase 3 Study of ANX005 in Patients with Guillain-Barré Syndrome

   GBS-02: A Phase 3 Study to Evaluate Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of ANX005 in Patients with Guillain-Barré Syndrome (GBS) Presenter: Jeffrey Allen, MD Jeffrey Allen, MD1; Henk-André Kroon, MD, MBA2; Zhahirul Islam, PhD3; Peter Collins2; Benjamin Hoehn, MD, PhD2; Eric Hump

2. Slide 2: Complement Inhibition With Tanruprubart (ANX005) Leads to Rapid, Robust Benefit Across Multiple Endpoints in GBS

   Complement Inhibition With Tanruprubart (ANX005) Leads to Rapid, Robust Benefit Across Multiple Endpoints in Patients With GBS GBS is a complement mediated neuromuscular emergency with significant unmet need despite current treatment options Tanruprubart Inhibits C1q to rapidly and completely shut d

3. Slide 3: GBS is a Neuromuscular Emergency with Significant Long-Term Disability With No FDA Approved Therapies

   GBS is a Neuromuscular Emergency with Significant Long-Term Disability With No FDA Approved Therapies Significant unmet need exists1 GBS is a complement mediated GBS is a rare, life-threatening post neuromuscular emergency1,8 infectious neuromuscular emergency2 ~7,000 hospitalized and treated in the

4. Slide 4: Complement Rapidly Drives Neuroinflammation and Nerve Damage During the Acute Progressive Phase of GBS

   Complement Rapidly Drives Neuroinflammation and Nerve Damage During the Acute Progressive Phase of GBS Leading to Disability ACUTE PLATEAU RECOVERY PROGRESSIVE Acute progressive phase: • Rapidly progressive bilateral muscle weakness peaking by 1 week in most cases and lasting up to 4 weeks Plateau p

5. Slide 5: Tanruprubart (ANX005) Is A Monoclonal Antibody Targeting C1q To Block The Classical Complement Pathway

   Tanruprubart (ANX005) Is A Monoclonal Antibody Targeting C1q To Block The Classical Complement Pathway At the Start C1q Is the Initiating Molecule of the Classical Complement Pathway C1q anchors to auto-antibodies on nerve surface and activates the pathway C1q C4a C4 C4b C2 INFLAMMATION AND EDEMA NE

6. Slide 6: Tanruprubart Rapidly Shuts Down Activation of the Classical Complement Pathway

   Tanruprubart (ANX005) Is A Monoclonal Antibody Targeting C1q To Block The Classical Complement Pathway At the Start C1q Tanruprubart Is the Initiating Rapidly MoleculeShutsof Down Activation the Classical of the ENTIRE Complement Pathway Classical C1q anchors Complement to auto-antibodies Pathway on

7. Slide 7: GBS-02 Was A Phase 3 Randomized, Double-blind, Placebo-controlled Study Of Tanruprubart

   GBS-02 Was A Phase 3 Randomized, Double-blind, and Placebo- controlled Study Of Tanruprubart (ANX005) In Patients With GBS Two doses selected to determine most effective duration of C1q inhibition Key Inclusion Criteria: Tanruprubart Tanruprubart • GBS Disability Score 3, 4 or 5 Placebo 30mg/kg 75mg

8. Slide 8: Shorter Duration of Complement Inhibition Showed Significant Treatment Effect on GBS-DS at Week 8

   Shorter Duration of Complement Inhibition Showed Significant and Clinically Meaningful Treatment Effect on GBS-DS at Week 8 Primary Endpoint: 2.4-Fold Higher Likelihood of Being in a Better State of Health Relative to Placebo 30 mg/kg 75 mg/kg OR 2.41, p=0.0058 OR 1.20, p=0.5548 Tanruprubart n=78 Ta

9. Slide 9: Rapid Recovery in Muscle Strength Is A Critical Prognostic Factor

   Tanruprubart (ANX005) 30 mg/kg Provided Rapid Recovery of Muscle Strength and Motor Function Rapid Recovery in Muscle Strength Is A Critical Prognostic Factor Of Clinically Meaningful Improvement Key Secondary Endpoint: More Than A 10-point Improvement In Muscle Strength 14 Times More Likely (MRC Su

10. Slide 10: Rapid and Immediate Impact To Disease Trajectory

    Rapid and Immediate Impact To Disease Trajectory Other Key Secondary Endpoints Demonstrated Treatment Benefit RAPID IMPROVEMENT IN MUSCLE STRENGTH (MRC SUM SCORE) REDUCED MOTOR DISABILITY (ONLS) Key Secondary Endpoint: Key Secondary Endpoint: Key Secondary Endpoint: 10.0-point 4.0-point -2.1-point -

11. Slide 11: Treatment Benefit is Durable, Leading to Increased Return to Normal Function

    Tanruprubart (ANX005) Treatment Benefit is Durable, Leading to Increased Return to Normal Function Across Multiple Measures of Function and Mobility ~2X+ times more treated patients fully recover on multiple measures at week 26 FULL RECOVERY NO LIMITATIONS GBS-DS=0 35% ONLS (TOTAL SCORE=0) 30 30%30

12. Slide 12: Tanruprubart Consistently Showed Faster Recovery Across Clinically Important Measures

    Tanruprubart (ANX005) Consistently Showed Faster Recovery Across Clinically Important Measures Helping Patients Achieve Their Independence Sooner Tanruprubart WALKING INDEPENDENTLY 56 Days 30 mg/kg: n=79 EARLIER Placebo 87 Days 31 days earlier1, p=0.0211 n=81 Tanruprubart 20 Days OFF VENTILATION EAR

13. Slide 13: Tanruprubart (ANX005) Was Generally Well-Tolerated

    Tanruprubart (ANX005) Was Generally Well-Tolerated Tanruprubart Tanruprubart Placebo 30 mg/kg 75 mg/kg MAJORITY OF AES WERE MILD (GRADE 1) n=81 n=79 n=81 TO MODERATE (GRADE 2) All Grades All Grades All Grades • Most common related events were Number of subjects reporting 79 (97.5) 79 (100.0) 80 (98.

14. Slide 14: Tanruprubart 30 mg/kg Single Dose Led to Rapid, Robust, and Consistent Benefit Across Multiple Endpoints

    Tanruprubart (ANX005) 30 mg/kg Single Dose Led to Rapid, Robust, and Consistent Benefit Across Multiple Endpoints First targeted Single dose rapidly blocks C1q and complement-mediated immunotherapy in GBS neuroinflammation and nerve damage 10-point point improvement in muscle strength at week 1 Clin

Annexon — American Academy of Neurology Annual Meeting 2025 on 6ix