Victrelis

Generic name: boceprevir

Drug class: Protease inhibitors

Dosage form: Capsules

Route of administration: Oral

Dose: 800 mg (four 200-mg capsules) orally three times daily (every 7 to 9 hours) with food

Mechanism of action: Boceprevir is a direct-acting antiviral agent that inhibits the hepatitis C virus (HCV) nonstructural protein 3 (NS3) serine protease, preventing the processing of viral polyproteins and thereby inhibiting viral replication in HCV genotype 1-infected host cells.

Drug usage cases:

• Chronic hepatitis C genotype 1 infection in adults with compensated liver disease, including cirrhosis, who are previously untreated or have failed previous interferon and ribavirin therapy.

Drug contraindications:

• Hypersensitivity to boceprevir or any of its components.
• Co-administration with drugs that are highly dependent on CYP3A4/5 for clearance, and for which elevated plasma concentrations are associated with serious and/or life-threatening events (e.g., alfuzosin, carbamazepine, phenobarbital, phenytoin, rifampin, dihydroergotamine, ergotamine, methylergonovine, cisapride, St. John’s Wort, lovastatin, simvastatin, drospirenone, sildenafil, tadalafil, pimozide, triazolam, and orally administered midazolam).
• Co-administration with potent CYP3A4/5 inducers (e.g., rifampin, St. John’s Wort), which may significantly reduce boceprevir plasma concentrations and efficacy.
• Use as monotherapy; must be administered in combination with peginterferon alfa and ribavirin.
• Pregnancy; boceprevir is contraindicated in pregnant women and in men whose female partners are pregnant due to the risk of birth defects and fetal death associated with ribavirin, which is part of the combination therapy.

Side effects:

• Fatigue
• Anemia (low red blood cell count)
• Nausea
• Headache
• Dysgeusia (taste disturbances)
• Neutropenia (low white blood cell count)
• Pancytopenia (reduction in all blood cell types) in serious cases
• Hypersensitivity reactions, including urticaria and angioedema

Warnings:

• Boceprevir must be administered in combination with peginterferon alfa and ribavirin; it is not approved for use as monotherapy.
• Monitor complete blood counts (with white blood cell differential counts) pretreatment, and at Treatment Weeks 2, 4, 8, and 12, and closely at other time points as clinically appropriate due to the risk of anemia and neutropenia.
• Discontinue therapy if HCV-RNA levels are greater than or equal to 1000 IU/mL at Treatment Week 8, greater than or equal to 100 IU/mL at Treatment Week 12, or if HCV-RNA is detectable at Treatment Week 24, as these may indicate treatment futility.
• Serious acute hypersensitivity reactions, such as urticaria and angioedema, have been observed; discontinue therapy and initiate appropriate medical therapy immediately if such reactions occur.
• Boceprevir is a strong inhibitor of CYP3A4/5 and is partly metabolized by CYP3A4/5; consider potential drug-drug interactions prior to and during therapy.

Use during pregnancy or breastfeeding:

Boceprevir is contraindicated in pregnant women and in men whose female partners are pregnant due to the risk of birth defects and fetal death associated with ribavirin, which is part of the combination therapy. Effective contraception (at least two reliable forms) is required during ribavirin therapy and for at least 4 to 7 months after the last dose. Boceprevir has not been studied in breastfeeding women; consult a healthcare provider before using boceprevir while breastfeeding.