Annexon Submits Marketing Authorization Application for Tanruprubart to Treat Guillain-Barré Syndrome

According to a new announcement, Biopharmaceutical company Annexon recently submitted their marketing authorization application (MAA) to the European Medicines Agency (EMA) for tanruprubart, a complement-targeting agent, as a treatment for Guillain-Barré syndrome (GBS), a rare neuroinflammatory disease.

The MAA submission for tanruprubart, an investigational, first-in-class monoclonal antibody, included extensive data from a proof-of-concept study and a phase 3 trial demonstrating the drug’s impact on markers of neuroinflammation and disease. In these studies, patients on the investigational drug experienced a faster and more complete recovery on both functional and clinical disability outcome measures.

Annexon believes it submitted a robust generalizability package that demonstrates tanruprubart’s effectiveness in patient populations outside Southeast Asia. This includes namely a large U.S. and Southeast Asian biomarker dataset, population pharmacokinetics (PK) analysis of tanruprubart across U.S., E.U. and Southeast Asian studies, and a 2000-patient, Real-World Evidence, GBS observational, phase 3 study matching patients to IVIg- or plasma exchange.

“In the landmark Phase 3 study, tanruprubart was shown to rapidly stop neuroinflammation, enabling GBS patients to recover faster and more completely from this sudden, life-threatening disease that has no approved disease modifying therapies,” said Douglas Love, president and chief executive officer of Annexon in a statement.¹ “Accordingly, we look forward to working closely with the EMA during the review and further collaborating with regulatory authorities worldwide to make available the first targeted treatment for GBS. This submission is an important step on many fronts as we move closer to achieving our mission of helping millions of patients impacted by devastating neuroinflammatory diseases live their best lives.”

In terms of pharmacokinetics, tanruprubart is designed to be administered intravenously to reduce inflammation and nerve damage by stopping C1q activity in the peripheral and central nervous systems. The aim of this agent is to rapidly block classical complement-driven inflammation on nerve cells, allowing patients to recover sooner, regain independence and return to pre-illness activities. To date, tanruprubart has received both Fast Track and Orphan Drug designations from the FDA as well as orphan drug designation from the EMA for the treatment of GBS.

Read More: The Complement Connection in Guillain-Barre and Chronic Inflammatory Demyelinating Polyneuropathy

The MAA submission from Annexon comes after positive safety and efficacy results from a phase 3 trial (NCT04701164) where tanruprubart was tested in patients with GBS. presented at the 2025 Peripheral Nerve Society (PNS) Annual Meeting, held May 17-20, in Edinburgh, Scotland, investigators reported the treatment demonstrated early, sustained improvements in perceived disability and quality-of-life measures.²

The analysis included 241 patients with GBS aged 16 years and older who were randomized to receive a single IV infusion of tanruprubart at either 30 mg/kg, 75 mg/kg, or placebo. Patients in the 30 mg/kg group showed significant improvement on the EQ visual analog scale (EQ-VAS) at the first time point measured at week 1 (P = .0089), which remained through week 8 (P = .0391), based on a mixed model for repeated measures (MMRM). Improvements in perceived disability, measured by the Patient Global Impression of Change (PGIC), were also observed by week 1.

Presented by lead author Glenn Morrison, PhD, vice president of clinical development at Annexon Biosciences, significant improvements were reported at week 1 in the tanruprubart-treated groups using proportional odds regression for the EQ5D-5L domains including mobility (OR = 5.65; P <.0001), self-care (OR = 9.50; P <.0001), and usual activity (OR = 7.42; P <.0001). These benefits continued over the first 8 weeks of the study. Additionally, the 30 mg/kg group experienced a 20% improvement in the country-standardized index score after 1 week of treatment (MMRM, P <.0001).

REFERENCES
1. Annexon Submits Tanruprubart Marketing Authorization Application to the European Medicines Agency for Guillain-Barré Syndrome. News Release. January 8, 2026. Accessed January 9, 2026. https://finance.yahoo.com/news/annexon-submits-tanruprubart-marketing-authorization-130000056.html
2. Glenn Morrison, Ping Lin, Quazi Deen Mohammad, et al. ANX005 improves health-related quality of life in patients with GBS compared to placebo. Presented at: 2025 Peripheral Nerve Society (PNS) Annual Meeting; May 17-20; Edinburgh, Scotland. P338.