Bones & muscles Complement C5 inhibitor peptide
Zilucoplan
Regulatory status
Status at a glance
503A compounding status
Not nominated
We found no pending nomination for the 503A bulks list. Unless the substance has another legal pathway (for example, a USP monograph or use in an FDA-approved drug), 503A pharmacies generally may not compound with it.
- FDA approval
- An FDA-approved product contains this peptide
- 503B outsourcing
- Not determined
- Anti-doping (WADA)
- Not on the WADA Prohibited List
- DEA schedule
- Not a controlled substance
About peptide status
Most peptides discussed here are not FDA-approved for any use, and products labeled “research use only” are not for human use. Removal from Category 2 does not authorize compounding. PCAC votes are non-binding recommendations; FDA and HHS make the final decisions.
This is not medical or legal advice, and we do not publish dosing, sourcing or reconstitution information. Talk with a licensed clinician before using any peptide.
If you think you are having a medical emergency, call 911.
Key takeaway
Zilucoplan (sold as Zilbrysq) is a macrocyclic peptide that blocks complement protein C5, used to treat generalized myasthenia gravis in adults who carry a specific antibody. By preventing complement damage at the nerve-muscle junction, it improves daily function. It has been FDA-approved in the U.S. since 2023 and is a once-daily self-injection.
At a glance
- What it is
- A complement C5 inhibitor, a macrocyclic peptide
- Approved for
- Generalized myasthenia gravis in adults who are anti-acetylcholine-receptor antibody positive
- Key fact
- In the RAISE trial it significantly improved myasthenia gravis daily-living scores versus placebo at 12 weeks
- Route
- Subcutaneous injection, once daily (self-administered)
- Evidence strength
- FDA approved
Summary
Zilucoplan (Zilbrysq) is an FDA-approved peptide that blocks complement C5 in antibody-positive myasthenia gravis. Learn how it works and its risks.
What is zilucoplan?
Zilucoplan, sold under the brand Zilbrysq, is a synthetic macrocyclic (ring-shaped) peptide that inhibits complement component C5. It treats generalized myasthenia gravis (gMG), an autoimmune disease in which antibodies attack the connection between nerve and muscle, causing weakness. It is used specifically in patients whose disease is driven by antibodies to the acetylcholine receptor. It was developed under the code RA101495 and approved in the United States in 2023.
How does zilucoplan work?
Zilucoplan binds complement protein C5 and blocks its cleavage into the fragments C5a and C5b, which prevents assembly of the membrane attack complex, the complement structure that punches holes in cell membranes. In antibody-positive generalized myasthenia gravis, antibodies against the acetylcholine receptor recruit complement to the neuromuscular junction, and the resulting membrane attack complex damages the muscle's receptor-bearing surface, impairing signal transmission and causing weakness. By blocking C5, zilucoplan protects that junction from complement damage.
As a small peptide, it can be given as a simple once-daily subcutaneous injection that patients administer themselves, which is a practical contrast to intravenous complement therapies. In the phase 3 RAISE trial, zilucoplan significantly improved the myasthenia gravis activities-of-daily-living score compared with placebo at 12 weeks.
Is it FDA-approved?
Editor’s note
Status: Yes. Zilucoplan was approved by the FDA in 2023 for generalized myasthenia gravis in adults who are anti-acetylcholine-receptor antibody positive. It carries a boxed warning for serious meningococcal infections, requires meningococcal vaccination, and is dispensed only through a risk management program.
Category: FDA-approved · Primary body area: Bones & muscles
Yes. Zilucoplan was approved by the FDA in 2023 for generalized myasthenia gravis in adults who are anti-acetylcholine-receptor antibody positive. It carries a boxed warning for serious meningococcal infections, requires meningococcal vaccination, and is dispensed only through a risk management program.
What is zilucoplan prescribed for?
Zilucoplan is prescribed for generalized myasthenia gravis in adults who test positive for antibodies to the acetylcholine receptor. It is self-injected once daily, offering an at-home option within the complement-inhibitor class.
What are the side effects?
According to the prescribing information, common side effects include:
- Injection-site reactions and bruising
- Upper respiratory tract infections
- Diarrhea
More serious considerations include:
- A boxed warning for serious meningococcal infections, requiring vaccination and a risk management program
- Other serious infections
- Pancreatitis and pancreatic cysts
Sources: FDA prescribing information for Zilbrysq; the RAISE trial (Howard et al., The Lancet Neurology, 2023, DOI: 10.1016/S1474-4422(23)00080-7), indexed on PubMed. This document is educational and does not constitute medical advice.
Registered human trials
0 registered human trials on ClinicalTrials.gov that we reviewed
Sources
- [1]
- [2]
approved (PDF)
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