By Fineline Cube 
Belgium-based biopharma UCB (EBR: UCB) announced that it has received marketing approval from China‘’s National Medical Products Administration (NMPA) for Rystiggo (rozanolixizumab). This chimeric monoclonal antibody is now approved for use in combination with conventional therapy for adult generalized myasthenia gravis (gMG) patients who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.
Mechanism and Significance
Rystiggo, a neonatal Fc receptor blocker, offers new treatment options for AChR-positive patients and addresses the unmet need for effective therapies for MuSK-positive patients in China.
Clinical Trial Results
Results from the pivotal Phase III MycarinG study, published in Lancet Neurology in 2023, demonstrated significant clinical benefits and good safety of Rystiggo in both AChR-positive and MuSK-positive gMG patients. Key findings include:
- Rapid symptom improvement and enhanced daily activity ability within one week of treatment.
- A 73% reduction in total IgG after the first treatment cycle, compared to a 9% reduction in the control group.
- An average improvement of 3.37 points in the MG-ADL score, versus a 0.78 point improvement in the control group.
- Particularly notable efficacy in MuSK-positive patients, with an average improvement of 7.28 points in MG-ADL, compared to a 2.28 point deterioration in the control group.
Long-Term Benefits and Safety
The benefits of Rystiggo were shown to be sustained after a single treatment. In the open-label extension of the MycarinG study, patients received an average of 3.4 treatment cycles (17.8 infusions) per year. The safety profile indicated that the overall risk of adverse events was comparable to placebo, with most events being mild or moderate, and good long-term safety was observed.