Gefurulimab showed sustained clinical improvements through 52 weeks in the Phase 3 PREVAIL trial in adults with AChR antibody-positive generalised myasthenia gravis.
Written by: Anamika Koshti, PharmD
Reviewed By: Pharmacally Editorial Team
Alexion, AstraZeneca Rare Disease, will present 52-week data from the Phase 3 PREVAIL trial (NCT01212991) supporting sustained clinical improvements with gefurulimab, a once-weekly subcutaneous self-administered C5 inhibitor, in adults with anti-acetylcholine receptor antibody-positive generalised myasthenia gravis (gMG).
Sustained Clinical Improvements Through 52 Weeks
The 52-week open-label extension data show that patients treated with gefurulimab maintained improvements in key measures of gMG disease activity, including the Myasthenia Gravis Activities of Daily Living (MG-ADL), Quantitative Myasthenia Gravis (QMG), and Myasthenia Gravis Composite (MGC) scores.
Among patients receiving gefurulimab, least-squares mean changes from baseline at week 52 were −5.3 for MG-ADL, −5.3 for QMG and −9.4 for MGC. The corresponding 95% confidence intervals were −5.8 to −4.8, −6.0 to −4.6 and −10.3 to −8.5, respectively.
Patients who switched from placebo to gefurulimab at week 26 also improved after treatment initiation. At week 52, least-squares mean changes from baseline were −4.9 for MG-ADL, −4.6 for QMG and −8.3 for MGC.
Gefurulimab remained well tolerated during the extension period, with no meningococcal infections reported.
Early Response and Reduced Need for Rescue Treatment
A post-hoc analysis of PREVAIL long-term data found that patients receiving gefurulimab achieved clinical responses as early as week one, with improvements sustained through week 52. The analysis also evaluated minimal symptom expression over the longer treatment period.
Additional week-26 analyses showed lower risks of gMG-related hospitalisation and rescue therapy use among patients treated with gefurulimab compared with placebo.
These findings add clinical outcomes beyond changes in disease-specific rating scales, particularly because hospitalisation and rescue treatment can reflect inadequate disease control in gMG.
C5 Inhibition and Neuromuscular Junction Injury
Gefurulimab is a dual-binding nanobody that inhibits complement component C5. Complement activation contributes to neuromuscular junction injury in AChR antibody-positive gMG, disrupting signal transmission between nerves and muscles.
The new clinical findings will be accompanied by preclinical research evaluating an integrated biomarker platform in a rodent model of MG. The platform combines in vivo nerve-evoked muscle function measurements with analysis of neuromuscular junction morphology.
In the model, C5 inhibition was associated with partial recovery of neuromuscular junction structure and muscle function. The findings support further evaluation of the platform for characterising disease progression and treatment response in preclinical MG research.
Digital Monitoring Adds a Patient-Centred Dimension
Separate data from the ME&MG™ open study, presented in collaboration with Ad Scientiam, will assess the potential clinical relevance of digital biomarkers generated through the ME&MG application.
The analysis found that digital biomarkers reflected gMG severity as classified by Myasthenia Gravis Foundation of America groups. The findings support further investigation of digital symptom tracking as a tool for monitoring disease burden and potentially informing clinical care.
Upcoming Clinical Data
Alexion will present 15 analyses across the AANEM Annual Meeting and MGFA Scientific Session in Orlando, Florida, from September 29 to October 2, 2026. The programme includes the 52-week PREVAIL findings, additional week-26 clinical and quality-of-life analyses, and translational research in MG.
The longer-term clinical dataset will help define the durability of gefurulimab’s treatment effect and its safety profile with continued administration, while the additional analyses may provide further context on its potential role as a self-administered treatment option for adults with AChR antibody-positive gMG.
Reference
Alexion advances pioneering leadership in gMG care with data at 2026 AANEM Annual Meeting and MGFA Scientific Session, Astra Zeneca, 24 September 2026
A Safety and Efficacy Study of Oral MDV3100 in Chemotherapy-Naive Patients with Progressive Metastatic Prostate Cancer (PREVAIL), ClinicalTrials.gov ID NCT01212991
About the Writer
Anamika Koshti (LinkedIn) is a PharmD professional and healthcare writer with interests in clinical research, pharmacovigilance, and evidence-based medicine. She has authored peer-reviewed publications on Alzheimer’s disease and PCOS, presented research at national conferences, and gained hands-on experience in medical content development and clinical data interpretation. She is committed to translating complex medical research into accurate, accessible content for healthcare professionals and patients.