Investigational Imlifidase Shows Rapid and Sustained Improvement of Guillain-Barré Syndrome Symptoms

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Key Takeaways

Imlifidase combined with IVIg showed rapid symptom improvement in severe GBS patients, with 37% walking independently within a week.
The treatment led to significant functional recovery, with 67% walking independently and 40.7% running after 8 weeks.
Imlifidase acts by cleaving IgG antibodies, offering faster action than traditional GBS therapies like plasma exchange and IVIg.
While approved for kidney transplant desensitization in the EU, imlifidase remains investigational for GBS, requiring further research.

Among patients with severe Guillain-Barré syndrome, imlifidase plus IVIg resulted in improved mobility, strength, and disability scores, with sustained benefit over a 6-month time period.

Shahram Attarian, head, Department of Neuromuscular Diseases and ALS, Hopitaux Universitaires de Marseille

Shahram Attarian, MD, PhD

In an open-label, single-arm, phase 2 trial (NCT03943589), treatment with a single dose of Hansa Biopharma’s imlifidase, an IgG-cleaving antibody, followed by intravenous immunoglobulin (IVIg) led to swift and sustained enhancement of symptoms in patients with Guillain-Barré syndrome (GBS). Presented at the 2025 Peripheral Nerve Society (PNS) Annual Meeting, held May 17-20, in Edinburgh, Scotland, these data further reinforce the therapeutic potential of imlifidase in the treatment of GBS.¹

After excluding patients re-diagnosed with other conditions, the study featured 27 individuals with confirmed severe GBS who received imlifidase 0.25 mg/kg intravenously within 12 days of symptom onset followed by IVIg (0.4 mg/kg/day for 5 days, 48 hours after imlifidase. The effects of imlifidase were observed quickly, as 37% of treated patients were able to walk independently within 1 week of treatment. In addition, participants demonstrated an improvement in muscle strength, reflected by mean of 10.7 points in Medical Research Council (MRC) sum score.

Led by Shahram Attarian, MD, PhD, head, Department of Neuromuscular Diseases and ALS, Hopitaux Universitaires de Marseille, treatment with imlifidase plus IVIg led to rapid functional improvement, with a median time of 6 days to achieve at least 1-grade gain on the GBS Disability Scale (GBS DS). In addition, the median time to independently walk for participants was 16 days on treatment.

After 8 weeks of treatment, 67% of patients were able to walk independently, 40.7% of patients had regained the ability to run, and 37% of the patients had improved by at least 3 points in the GBS DS. At the 6-month time point, 63% of treated participants were able to run or had no functional disability, considered GBS DS of 1 or less. Above all, the agent continued to show a safe and well tolerated profile, with no unexpected safety concerns.

Imlifidase is an enzyme derived from Streptococcus pyogenes that cleaves all subclasses of human IgG antibodies. It acts rapidly, degrading circulating IgG within hours of administration, thereby preventing or interrupting IgG-mediated autoimmune attacks. To date, it is approved in the European Union for desensitizing kidney transplant patients and remains investigational for the treatment of GBS.

Within the GBS treatment landscape, imlifidase differs slightly from traditional plasma exchange and IVIg. IVIg, which neutralizes autoantibodies, has a slower onset, and may be suboptimal in severe cases. Plasma exchange, intended to physical remove autoantibodies, is resource-intensive and not always feasible. Imlifidase has the potential to act faster than existing therapies, although there is more data needed on its mechanism and therapeutic benefits.

Prior to the phase 2 study, imlifidase was assessed in several phase 1 trials, including a study of healthy male volunteers. Published in Clinical Kidney Journal in March 2024, the study demonstrated that the agent was well-tolerated and effectively cleaved IgG antibodies within hours of administration, confirming its rapid onset of action.² Two other subsequent, independent phase 1-2 studies involving highly sensitized patients with kidney transplants also further supported imlifidase’s development. All told, data revealed that imlifidase effectively reduced or eliminated donor-specific antibodies, enabling successful transplantation in 24 of the 25 observed patients.³

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