VILTEPSO
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VILTEPSO (VILTEPSO).
Antisense oligonucleotide that binds to exon 51 of dystrophin pre-mRNA, excluding it during splicing to restore the reading frame and produce a truncated but functional dystrophin protein in patients with Duchenne muscular dystrophy (DMD) with confirmed mutations amenable to exon 51 skipping.
| Metabolism | Primarily metabolized via exonuclease-mediated hydrolysis, not via cytochrome P450 enzymes; renal excretion of oligonucleotide metabolites. |
| Excretion | Viltepso is primarily eliminated via renal excretion. Approximately 60-70% of the administered dose is excreted unchanged in urine within 24 hours, with minimal biliary/fecal elimination (less than 5%). |
| Half-life | The terminal elimination half-life is approximately 3-4 weeks in plasma, reflecting slow clearance due to tissue binding and prolonged intracellular retention. Clinically, this supports weekly intravenous dosing. |
| Protein binding | Protein binding is negligible (<5%), as viltepso is an antisense oligonucleotide with low affinity for plasma proteins. |
| Volume of Distribution | The volume of distribution is approximately 1.5-2.0 L/kg, indicating extensive tissue distribution, particularly to skeletal muscle, which is the target tissue. |
| Bioavailability | Bioavailability is 100% following intravenous administration; oral bioavailability is negligible (<1%) due to degradation in the gastrointestinal tract. |
| Onset of Action | Intravenous administration: Clinical effect (dystrophin expression) is measurable after 2-4 weeks of weekly dosing, with peak effect typically observed after 12-24 weeks of continuous therapy. |
| Duration of Action | The duration of action is prolonged, with sustained dystrophin expression persisting for several weeks after discontinuation. Weekly dosing maintains therapeutic levels; clinical benefit is lost if dosing is interrupted for more than 4-6 weeks. |
30 mg/kg intravenously once weekly.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment recommended for renal impairment; not studied in dialysis. |
| Liver impairment | No dosage adjustment recommended for hepatic impairment; not studied in Child-Pugh classes. |
| Pediatric use | Approved for Duchenne muscular dystrophy in ambulatory patients aged 4 years and older; dose is 30 mg/kg intravenously once weekly. |
| Geriatric use | No specific dose adjustment; limited data in patients ≥65 years. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VILTEPSO (VILTEPSO).
| Breastfeeding | No data on excretion in human milk; M/P ratio unknown. Consider developmental and health benefits of breastfeeding alongside mother's need for viltolarsen. |
| Teratogenic Risk | No human data available; animal studies show no teratogenicity at clinically relevant doses. Risk cannot be excluded; use only if benefit outweighs risk. |
| Fetal Monitoring | Monitor for renal function and potential hypersensitivity reactions. No specific fetal monitoring required beyond standard obstetric care. |
■ FDA Black Box Warning
None
| Serious Effects |
None
| Precautions | ["Renal toxicity including potentially fatal glomerulonephritis","Hypersensitivity reactions including angioedema, urticaria, and rash","Thrombocytopenia","Animal studies show testicular degeneration and impaired fertility"] |
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| Fertility Effects | No studies on fertility; animal studies show no impairment at clinically relevant doses. Effect on human fertility unknown. |