Zilucoplan, which is a synthetic, macrocyclic peptide, achieved clinically meaningful and statistically significant reductions across the primary and key secondary endpoints for its two dose groups in comparison to placebo at 12 weeks of treatment of the chronic, autoimmune, neuromuscular disease.
Dosed daily at 0.3mg/kg subcutaneously (SC), the investigational drug registered a mean reduction from baseline of 6.0 points in the Quantitative Myasthenia Gravis (QMG) score.
It also achieved a mean reduction from baseline of 3.4 points in the MG Activities of Daily Living (MG-ADL) score with no patients treated with the 0.3mg/kg dose needing rescue therapy.
The phase 2 trial held in 44 patients in the US and Canada evaluated the safety, tolerability, and preliminary efficacy of the drug in patients with gMG.
The patients in the trial were selected irrespective of prior therapies, who had a MGFA Disease Class of II-IVa at screening, and a QMG score of ≥ 12 at screening and randomization.
Patients were randomly grouped in a 1:1:1 ratio for treatment with 0.1mg/kg of zilucoplan, 0.3mg/kg of the same drug, or matching placebo.
Ra Pharmaceuticals said the pre-specified primary efficacy endpoint of the phase 2 trial was the variation in QMG score from baseline to week 12 while the key secondary efficacy endpoint was the difference in MG-ADL score.
The US-based clinical stage biopharma company said that treatment with zilucoplan showed a favorable safety and tolerability profile during the phase 2 study, which was on par with previously-completed phase 1 and phase 2 trials.
Ra Pharma is planning a phase 3 clinical trial to evaluate the 0.3mg/kg dose of zilucoplan against placebo in patients with gMG.
Ra Pharma founder and CEO Doug Treco said: “Designed for subcutaneous self-administration, zilucoplan offers convenience and accessibility, giving it the potential to bring C5 inhibition to the forefront of the treatment paradigm for gMG.
“We look forward to meeting with regulators to review our Phase 2 data and the design of our planned Phase 3 program with the ultimate goal of transforming the lives of thousands of patients with this disease.”