SCY-635

Cyclosporin Analog (non Immunosuppressive Cyclophilin Inhibitor)Rx: ResearchCompound: Investigational

Also known as: non-immunosuppressive cyclosporin A analog, SCY635, Scynexis cyclophilin inhibitor

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

Summary

SCY-635 is a synthetic non-immunosuppressive analog of cyclosporine A developed by Scynexis Inc. for the treatment of chronic hepatitis C virus (HCV) infection. It potently inhibits cyclophilin A, a host factor required for HCV replication, and has demonstrated antiviral activity across multiple HCV genotypes in clinical studies. It also showed synergistic activity in combination with pegylated interferon alfa. Development was discontinued prior to regulatory approval.

Mechanism of Action

Binds cyclophilin A (CypA) with high affinity, inhibiting its peptidyl-prolyl isomerase activity and blocking CypA-mediated viral replication; disrupts hepatitis C virus (HCV) replication by preventing CypA interaction with NS5A and other replication complex components, without significant calcineurin inhibition and thus lacking the immunosuppressive activity of cyclosporine A

Routes of Administration

Oral

Goals & Uses

  • Combination antiviral therapyAntiviralModerate
  • Pan-genotypic HCV coverageAntiviralModerate
  • Avoidance of immunosuppressionSafety ProfileModerate
  • HCV antiviral activityAntiviralModerate

Contraindications

  • Hypersensitivity to cyclosporine or cyclosporin analogsAllergyHigh
  • Severe renal impairmentOrganModerateKidney function concerns
  • PregnancyPopulationHighPotential fetal risk or insufficient safety data

Adverse Effects

  • HeadacheNeurologicCommonPain in the head or upper neck
  • Gastrointestinal disturbances (nausea, diarrhea)GastrointestinalCommon
  • FatigueGeneralCommonLow energy or tiredness
  • Elevated serum creatinineRenal / LaboratoryUncommon
  • HyperbilirubinemiaHepaticUncommon

Drug Interactions

  • Pegylated interferon alfaLow
  • CYP3A4 inducers (e.g., rifampin, carbamazepine)Moderate
  • Immunosuppressants (e.g., tacrolimus, cyclosporine A)High
  • CYP3A4 inhibitors (e.g., ketoconazole, ritonavir)High

Population Constraints

  • Pediatric patientsAgeRelative
  • Patients with hepatic impairmentOrgan FunctionRelative
  • Organ transplant recipients on immunosuppressionComorbidityRelative

Regulatory Status

  • European UnionInvestigationalNo marketing authorization application submitted; investigational status only
  • United StatesInvestigationalCompleted Phase II trials for chronic HCV; no NDA filed; development discontinued
  • United KingdomInvestigationalNo regulatory submission; research/investigational use only

SCY-635 completed Phase II clinical trials for HCV but was not advanced to Phase III or submitted for regulatory approval. No approved status in any jurisdiction. Investigational use only.

Evidence & Sources

No sources recorded yet.

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