Belnacasan

Summary

Belnacasan (VX-765) is an orally bioavailable prodrug that is converted in vivo to its active metabolite VRT-043198, a potent and selective caspase-1 inhibitor. It was investigated primarily for epilepsy and inflammatory conditions. Clinical development was discontinued after Phase II trials did not meet primary endpoints.

Mechanism of Action

Selective, reversible inhibitor of caspase-1 (interleukin-1 beta converting enzyme, ICE), blocking the proteolytic cleavage and maturation of pro-IL-1β and pro-IL-18, thereby reducing downstream inflammatory signaling.

Routes of Administration

Goals & Uses

• Inhibition of IL-1β-driven inflammationInflammationModerate
• NeuroprotectionNeurologyLow
• Reduction of seizure frequency in epilepsyNeurologyModerate
• Treatment of inflammatory/autoimmune conditionsImmunologyLow

Contraindications

• Severe hepatic impairmentOrganModerateLiver function concerns
• Hypersensitivity to belnacasan or excipientsAllergyHigh

Adverse Effects

• HeadacheNeurologicCommonPain in the head or upper neck
• NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
• Increased infection susceptibilityImmunologicalRare
• Elevated liver enzymesHepaticUncommonIncrease in AST/ALT or other hepatic markers
• DizzinessNeurologicUncommonFeeling faint, lightheaded, or unsteady

Drug Interactions

• Antiepileptic drugs (e.g., valproate, carbamazepine)Low
• CYP3A4 inhibitors (e.g., ketoconazole)Moderate
• ImmunosuppressantsModeratePotential interaction with immune pathways or infection risk

Population Constraints

• Pediatric patientsAgeRelative
• Immunocompromised patientsImmunologicRelative
• Pregnant womenReproductiveRelative

Regulatory Status

• European UnionInvestigationalClinical trials conducted in EU jurisdictions; no EMA approval granted.
• United StatesInvestigationalIND granted for clinical trials; never received FDA approval. Development discontinued post Phase II.
• United KingdomInvestigationalNo MHRA approval; investigational use only.

Belnacasan was never approved by any major regulatory agency. Phase II trials in epilepsy were conducted but the program was discontinued. It remains a research tool compound.

Evidence & Sources

No sources recorded yet.

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