Rystiggo(rozanolixizumab)

Rystiggo (rozanolixizumab) is a drug for which scientific advice was received from the CHMP on 29/05/2019 and 16/12/2021. It demonstrates high affinity for human FcRn, with a KD of 55 pM at pH 7.4 and 44 pM at pH 6.0. In cell-based assays, its potency to human FcRn ranged from 0.36-0.43 nM, and it showed an IC50 of 0.4 nM for human FcRn in IgG recycling experiments. The absolute bioavailability of rozanolixizumab is 67%.

In healthy Caucasian volunteers, a mean decrease in IgG of 50.76% was observed. For patients, predicted decreases from baseline total IgG after 6 weekly doses of 560 mg were 65.3% for a 122 kg patient and 76.1% for a 46 kg patient. The maximum dose of rozanolixizumab administered in patients was 11.2 mg/kg.

Regarding safety, discontinuations due to adverse events in the MG0003 study were 5 in the ≈10mg/kg group and 2 in the ≈7mg/kg group. The incidence of drug-related hepatic disorders (TEAEs) was 4.8% overall, with 1.5% in the ≈7mg/kg dose group and 5.3% in the ≈10mg/kg dose group. Regulatory commitments include developing a quantitative assay for free fatty acids by Q4 2024 and implementing a two-tiered reference standard system by the end of Q1 2024.