Anti-FcRn drugs facilitate the elimination of IgG, which includes the autoantibodies produced in myasthenia gravis. The first drug in this family, efgartigimod (Vyvgart®), was granted US marketing authorization in late 2021. It is a humanized IgG1 fragment. Another anti-FcRn, batoclimab is a whole IgG1. A Phase II clinical trial evaluated two dosages (340 and 680 mg) in 30 adults with myasthenia gravis with anti-RACh or anti-MuSK autoantibodies. Its results show that, after four months of treatment, batoclimab :
- a clinically significant improvement in MG-ADL score more often than placebo ;
- a reduction in plasma IgG levels to -74.4% one week after the 6th injection at a dose of 680 mg
- without a concomitant increase in the frequency of infections versus placebo.
The evaluation of batoclimab is continuing in generalized myasthenia gravis with anti-RACh, anti-MuSK or seronegative via an ongoing Phase III trial involving 144 participants, also in China.
