Positive results from 2 phase 3 clinical trials of potential generalized myasthenia gravis (gMG) therapies were recently presented as posters at the 14th Myasthenia Gravis Foundation of America (MGFA) International Conference on Myasthenia and Related Disorders.

The 2 therapies, zilucoplan and rozanolixizumab, were both associated with improvements in Myasthenia Gravis Activities of Daily Living (MG-ADL) scores, according to a press release from their developer, UCB.

“Every person living with gMG is unique, so a one-size-fits-all treatment approach will never be appropriate. This is why at UCB we are investigating two medicines with different [mechanisms of action],” said Iris Loew-Friedrich, executive vice president and chief medical officer at UCB. “This unique approach means we may be able to offer physicians and patients a range of treatment options to meet the individual needs of many different patients, and therefore leave no one behind in our ambition to improve outcomes in gMG.”

Based on the positive results from the trials of both therapies, UCB anticipates filing regulatory submissions later this year.

Read more about experimental therapies for MG.

Zilucoplan, a peptide inhibitor of complement component 5 (C5 inhibitor), was investigated in the phase 3 RAISE study (NCT04115293). The study showed that treatment with 0.3 mg/kg daily of zilucoplan resulted in a 2.12 point placebo-corrected mean improvement in MG-ADL scores at week 12 (P <.001) in patients with acetylcholine receptor (AChR) autoantibody positive gMG. A significant improvement in score was observed as early as the first week, however.

Similar rates of treatment-emergent adverse events (TEAEs) were observed between the treatment and placebo groups, indicating a favorable safety and tolerability profile, according to UCB.

The phase 3 MycarinG study (NCT03971422) investigated the use of 2 different doses of rozanolixizumab (~7 mg/kg and ~10 mg/kg) compared to placebo in patients with AChR or muscle-specific tyrosine kinase (MuSK) autoantibody positive gMG. Placebo-corrected mean improvements in MG-ADL scores were 2.586 points for the ~7 mg/kg dose and 2.619 points at the ~10 mg/kg dose.

Both treatment levels also resulted in a more than 70% reduction in maximum total immunoglobulin G (IgG) levels. A higher percentage of TEAEs were reported in treated patients compared to placebo, however, (81.3% for ~7 mg/kg and 82.6% for ~10 mg/kg vs 67.2% for placebo). 

“The one constant in gMG is unpredictability. People living with this disease experience symptoms that are nebulous, fluctuating, and which vary from one day to the next,” said Vera Bril, professor of medicine (neurology) and director of the neuromuscular section, division of neurology, University of Toronto and University Health Network, Toronto, and lead investigator of the MycarinG study. “For this reason, there is an urgent need for more effective, targeted, and convenient treatments that reduce the burden of disease on patients’ daily lives.”

Reference

UCB presents efficacy and safety results for zilucoplan and rozanolixizumab in generalized myasthenia gravis. News release. UCB; May 10, 2022.