Pexelizumab

Complement Inhibitor (anti C5 Single Chain Antibody Fragment)Rx: ResearchCompound: Withdrawn

Also known as: 5G1.1-scFv, Alexion anti-C5 scFv, h5G1.1-scFv

Educational Only — Not medical advice. Consult a qualified clinician before using any peptide.

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Summary

Pexelizumab is an anti-C5 complement inhibitor developed by Alexion Pharmaceuticals that was investigated for reducing myocardial injury during cardiac surgery (CABG and PCI) and acute myocardial infarction. Despite promising phase II results, it failed to meet primary endpoints in large phase III trials (PRIMO-CABG II, APEX-AMI) and was not approved by regulatory authorities.

Mechanism of Action

Pexelizumab is a humanized single-chain antibody fragment (scFv) that selectively binds to complement component C5, preventing its cleavage into C5a and C5b. This inhibits the terminal complement pathway, blocking formation of the membrane attack complex (MAC) and reducing complement-mediated inflammation and tissue injury.

Routes of Administration

Intravenous

Goals & Uses

  • Reduction of myocardial injury post-CABGCardioprotectionModerate
  • Complement inhibition during cardiopulmonary bypassInflammatory ModulationModerate
  • Reduction of infarct size in STEMI/AMIAcute Myocardial InfarctionLow

Contraindications

  • Unvaccinated patients (meningococcal)Infectious DiseaseHigh
  • Active Neisseria meningitidis infectionInfectious DiseaseHigh

Adverse Effects

  • Increased susceptibility to encapsulated bacterial infectionsImmunologicalUncommon
  • HeadacheNeurologicCommonPain in the head or upper neck
  • Infusion-related reactionsHypersensitivityUncommon

Drug Interactions

  • Other immunosuppressantsModerate

Population Constraints

  • Pregnant womenReproductiveRelative
  • Patients with complement deficienciesImmunologicalRelative

Regulatory Status

  • European UnionUnapprovedEMA approval never granted; program discontinued.
  • United StatesUnapprovedFDA approval never granted; development discontinued after phase III failures.

Pexelizumab was never approved by the FDA or EMA. Development was discontinued following failure in pivotal phase III trials. No current active regulatory status in any major jurisdiction.

Evidence & Sources

No sources recorded yet.

Frequently Asked Questions

What is Pexelizumab?

Pexelizumab is an anti-C5 complement inhibitor developed by Alexion Pharmaceuticals that was investigated for reducing myocardial injury during cardiac surgery (CABG and PCI) and acute myocardial infarction. Despite promising phase II results, it failed to meet primary endpoints in large phase III trials (PRIMO-CABG II, APEX-AMI) and was not approved by regulatory authorities.

What is Pexelizumab used for?

Pexelizumab is educationally associated with: Reduction of myocardial injury post-CABG, Complement inhibition during cardiopulmonary bypass, Reduction of infarct size in STEMI/AMI. Educational only — not medical advice.

How is Pexelizumab administered?

Recorded routes of administration: Intravenous.

What are the potential side effects of Pexelizumab?

Reported adverse effects include: Increased susceptibility to encapsulated bacterial infections, Headache, Infusion-related reactions. This list is not exhaustive — consult a qualified clinician.

Who should avoid Pexelizumab?

Recorded contraindications: Unvaccinated patients (meningococcal), Active Neisseria meningitidis infection. Consult a qualified clinician before use.