Annexon's anx005 Shows Significant Improvements in GBS Phase 3 Trial

Annexon, Inc. (NASDAQ: ANNX) has released positive results from the completed pivotal phase 3 trial of anx005, a c1q-targeted immunotherapy, in Guillain-Barré Syndrome (GBS) at the 2024 Peripheral Nerve Society (PNS) Annual Meeting in Montréal, Canada.

The phase 3 data with anx005 30 mg/kg treatment showed significant improvements compared to the placebo across multiple pre-specified endpoints. Here are some key findings from the phase 3 GBS trial of anx005 30 mg/kg treatment:

  • Primary endpoint at week 8: 2.41-fold higher likelihood of being in a better state of health with anx005 vs. placebo
  • Week 1: 7.22-fold higher likelihood of being in a better state of health with anx005 vs. placebo
  • Week 4: 2.49-fold higher likelihood of being in a better state of health with anx005 vs. placebo
  • Week 26: 2.5 times more patients had fully recovered to a normal/pre-disease state of health with anx005 (21.5%) vs. placebo (8.6%)
  • Week 8 responder analysis: 2-times more patients improved 3 points or more with anx005 vs. placebo
  • Week 8 dichotomy analysis: 2.5-times more patients were able to run or better with anx005 vs. placebo
  • Walking 31 days earlier with anx005 treatment (56 days) vs. placebo (87 days)
  • Off ventilation 28 days earlier with anx005 treatment (20 days) vs. placebo (48 days)
  • Week 1: 8.8-point improvement in muscle strength measured by Medical Research Council (MRC) sumscore with anx005 vs. placebo
  • Week 8: 3 times more likely to be in a better state of health on the GBS-Disability Scale (GBS-DS) with anx005 vs. placebo

The results also showed that anx005-treated patients demonstrated faster and more complete recovery from week 1 through week 26 on primary and multiple pre-specified endpoints. Additionally, the beneficial impact of anx005 was larger in patients with North American and European baseline characteristics across key measures of disability and muscle strength.

Anx005, which has received fast track and orphan drug designations from the Food and Drug Administration as well as orphan drug designation by the European Medicines Agency for the treatment of GBS, is a first-of-its kind selective, targeted, and rapid-acting agent designed to reduce inflammation and nerve damage by fully stopping c1q activity in the peripheral and central nervous systems.

The company's lead investigational therapy has demonstrated its potential to be the first targeted immunotherapy treatment for GBS. The data from the phase 3 trial reinforce the therapeutic potential of anx005 and the potential to transform the GBS treatment landscape.

Annexon Biosciences is rigorously advancing its mid-to-late-stage clinical trials to bring potential treatments to patients as quickly as possible and is committed to addressing devastating classical complement-mediated neuroinflammatory diseases of the body, brain, and eye.

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, making the positive results from the phase 3 trial significant in addressing this severe disease.

Following these announcements, the company's shares moved -4.0%, and are now trading at a price of $4.58. Check out the company's full 8-K submission here.

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