RYSTIGGO

What it is

Rystiggo (rozanolixizumab) is a recombinant, humanised anti-neonatal Fc receptor (FcRn) IgG4P monoclonal antibody produced from a dihydrofolate reductase-deficient Chinese Hamster Ovary DG44 cell line. It is a solution for injection, for subcutaneous infusion. Each vial contains 140 mg of rozanolixizumab per mL of solution. Rozanolixizumab is a humanised immunoglobulin (Ig) G4 monoclonal antibody which decreases serum IgG concentration by inhibiting the binding of IgG to FcRn, a receptor that normally protects IgG from intracellular degradation and recycles IgG back to the cell surface. By the same mechanism, rozanolixizumab is expected to decrease the concentration of pathogenic IgG autoantibodies associated with gMG.

Approved indications

— Generalised myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive, as an add-on to standard therapy.

Dosing overview

Rystiggo is administered as subcutaneous infusion once a week in a treatment cycle of 6 weeks. The recommended total weekly dose depends on body weight: patients with body weight ≥35 to <50 kg receive 280 mg weekly; ≥50 to <70 kg receive 420 mg weekly; ≥70 to <100 kg receive 560 mg weekly; and ≥100 kg receive 840 mg weekly. Each subsequent treatment cycle may be administered based on clinical evaluation of symptom recurrence. Treatment with Rystiggo must be discontinued in patients who have not demonstrated a response within 3, 6-week treatment cycles, where a response is defined as a decrease of ≥2 points on the MG-ADL scale from baseline.

Key safety warnings

Aseptic meningitis (drug-induced aseptic meningitis) has been reported in patients treated with Rystiggo. If symptoms consistent with aseptic meningitis develop, diagnostic workup and treatment should be initiated according to the standard of care. Based on its mechanism of action, Rystiggo may increase the risk of infection. Treatment with Rystiggo should not be initiated in patients with a clinically important active infection until the infection resolves or is adequately treated. During treatment, monitor for clinical signs and symptoms of infections. If a clinically important active infection occurs, consider withholding Rystiggo until the infection has resolved. If a systemic hypersensitivity reaction occurs during administration, discontinue Rystiggo infusion and institute appropriate supportive measures if needed. Because rozanolixizumab binds to the FcRn blocking IgG uptake into the cell, IgG serum concentration decreases and Fc–peptide fusion proteins will decrease if administered concomitantly with Rystiggo. IgG based drugs (e.g., monoclonal antibodies and IVIg) may be affected. It is recommended to initiate these drugs 2 weeks after a Rystiggo infusion and monitor for attenuated efficacy of these medications when administered concomitantly. Because rozanolixizumab causes a reduction in IgG levels, vaccination with live-attenuated or live vaccines is not recommended during treatment. Evaluate the need to administer age-appropriate vaccines according to immunisation guidelines before initiation of a treatment cycle with Rystiggo.

Contraindications

Hypersensitivity to the active substance or to any of the excipients is a contraindication.

PBS listing

No information regarding PBS listing is available in the provided source documents.

Regulatory history

Rystiggo (rozanolixizumab) 140 mg/mL solution for injection for infusion vial was first registered on the ARTG on 7 February 2025. The TGA approved Rystiggo on 28 January 2025. In March 2025, the PBAC recommended Rystiggo as a new medicine for generalised myasthenia gravis (gMG) in adult patients who are anti-acetylcholine receptor antibody positive. This medicinal product is subject to additional monitoring in Australia, which will allow quick identification of new safety information.