MHLW (Japan) approves Rystiggo (rozanolixizumab) and Zilbrysq (zilucoplan), for the treatment of generalized myasthenia gravis in adult patients (only for patients who inadequately respond to steroids or other immunosuppressants)

Japan is the first country in the world to approve both rozanolixizumab and zilucoplan simultaneously. This means Japanese physicians and their patients will be the first to have choice of two new targeted therapies to treat gMG from one company, delivering unique optionality and versatility.

The Japanese MHLW approval of rozanolixizumab, for treatment of adults with generalized Myasthenia Gravis (only for patients who inadequately respond to steroids or other immunosuppressants) is the second approval worldwide for this medicine, following approval by the FDA in June 2023 for the treatment of gMG in adult patients who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.

Rozanolixizumab injection by subcutaneous infusion is a humanized IgG4 monoclonal antibody that binds to the neonatal Fc receptor (FcRn), resulting in the reduction of circulating IgG.

This announcement marks the first approval worldwide of zilucoplan, the first once-daily subcutaneous (SC), targeted peptide inhibitor of complement component 5 (C5 inhibitor) and the only gMG target therapy for self-administration by adult patients with AChR antibody-positive gMG. In September 2023, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) issued a positive opinion recommending granting marketing authorization for zilucoplan in the European Union (EU) as an add-on to standard therapy for the treatment of generalized myasthenia gravis (gMG) in adult patients who are anti acetylcholine receptor (AChR) antibody positive. A final decision on approval in the EU is expected before the end of the year, in line with the EMA’s standard review timeline.

As a C5 inhibitor, zilucoplan inhibits complement-mediated damage to the neuromuscular junction through its targeted dual mechanism of action. Benefits of SC self-injection can include reduced traveling time to and from hospitals, decreased interference with work obligations, and increased independence. Unlike monoclonal antibody C5 inhibitors, as a peptide, zilucoplan can be used concomitantly with intravenous immunoglobulin and plasma exchange, without the need for supplemental dosing.