Zilucoplan

Also known as: Zilbrysq, RA101495

A macrocyclic peptide C5 complement inhibitor for generalized myasthenia gravis. FDA-approved as Zilbrysq (2023). Prescription medication.

Last updated October 26, 2026

Mechanism of Action

Zilucoplan is a 15-amino-acid macrocyclic peptide that binds complement component C5. It blocks C5 cleavage into C5a and C5b and also interferes with C5b binding to C6, preventing formation of the membrane attack complex. In acetylcholine receptor antibody-positive myasthenia gravis, this limits complement-mediated damage at the neuromuscular junction.

Half-life: ~7-8 days
Administration Routes: Subcutaneous
Research Status: Clinical

Reported Benefits

Generalized myasthenia gravis in adults who are anti-AChR antibody positive
Improved MG-ADL and QMG scores vs placebo (RAISE)
Once-daily subcutaneous option rather than IV infusions

Potential Side Effects

Boxed warning: serious meningococcal infections
Injection-site reactions
Upper respiratory tract infection, diarrhea
Pancreatitis and elevated pancreatic enzymes (label warning)

Common Dosing

Zilbrysq is a once-daily subcutaneous injection in a weight-based prefilled-syringe dose. Meningococcal vaccination and enrollment in a REMS safety program are required before starting. Dosing is set and supervised by the prescribing clinician.

The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.

Contraindications

Unresolved serious Neisseria meningitidis infection
Not vaccinated against meningococcal infection unless risk outweighed

No documented stacking partners for Zilucoplan yet.

Safety and efficacy of zilucoplan in patients with generalised myasthenia gravis (RAISE): a randomised, double-blind, placebo-controlled, phase 3 study
2023
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Clinical Effects of the Self-administered Subcutaneous Complement Inhibitor Zilucoplan in Patients With Moderate to Severe Generalized Myasthenia Gravis: Results of a Phase 2 Randomized, Double-Blind, Placebo-Controlled, Multicenter Clinical Trial
2020
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Yes. The FDA approved zilucoplan as Zilbrysq in October 2023 for generalized myasthenia gravis in adults who are anti-acetylcholine receptor antibody positive. It is a prescription drug with a REMS program for meningococcal infection risk.

All three inhibit complement C5, but eculizumab and ravulizumab are antibodies given by IV infusion, while zilucoplan is a small macrocyclic peptide given as a daily subcutaneous injection.