Ribasphere (ribavirin, USP) should be taken with food. Ribasphere should be given in combination with peginterferon alfa-2a; it is important to note that Ribasphere should never be given as monotherapy. See Peginterferon alfa-2a Package Insert for all instructions regarding peginterferon alfa-2a dosing and administration.
2.1 Chronic Hepatitis C Monoinfection
Adult Patients
The recommended dose of Ribasphere tablets is provided in Table 1. The recommended duration of treatment for patients previously untreated with ribavirin and interferon is 24 to 48 weeks.
The daily dose of Ribasphere is 800 mg to 1200 mg administered orally in two divided doses. The dose should be individualized to the patient depending on baseline disease characteristics (e.g., genotype), response to therapy, and tolerability of the regimen (see Table 1).
Table 1 Peginterferon alfa-2a and Ribasphere Dosing Recommendations
Hepatitis C Virus (HCV)
Genotype
Peginterferon
alfa-2a Dose*
(once weekly)
Ribasphere Dose
(daily)
Duration
Genotypes 2 and 3 showed no increased response to treatment beyond 24 weeks (see Table 10).
Data on genotypes 5 and 6 are insufficient for dosing recommendations.
*See Peginterferon alfa-2a Package Insert for further details on peginterferon alfa-2a dosing and administration, including dose modification in patients with renal impairment.
Genotypes 1, 4
180 mcg
<75 kg = 1000 mg
≥75 kg = 1200 mg
48 weeks
48 weeks
Genotypes 2, 3
180 mcg
800 mg
24 weeks
Pediatric Patients
Peginterferon alfa-2a is administered as 180 mcg/1.73m2 x BSA once weekly subcutaneously, to a maximum dose of 180 mcg, and should be given in combination with ribavirin. The recommended treatment duration for patients with genotype 2 or 3 is 24 weeks and for other genotypes is 48 weeks.
Ribasphere should be given in combination with peginterferon alfa-2a. Ribasphere is available as a 200 mg, 400 mg and 600 mg tablet and therefore the healthcare provider should determine if this sized tablet can be swallowed by the pediatric patient. The recommended doses for Ribasphere are provided in Table 2. Patients who initiate treatment prior to their 18th birthday should maintain pediatric dosing through the completion of therapy.
Table 2 Ribasphere Dosing Recommendations for Pediatric Patients
*approximately 15 mg/kg/day
**or 1 x 400 mg tablet
***or 1 x 600 mg tablet
Body Weight in
kilograms (kg)
Ribasphere Daily Dose*
Ribasphere
Number of Tablets
23 – 33
400 mg/day
1 x 200 mg tablet A.M.
1 x 200 mg tablet P.M.
34 – 46
600 mg/day
1 x 200 mg tablet A.M.
2 x 200 mg tablets P.M.**
47 – 59
800 mg/day
2 x 200 mg tablets A.M.**
2 x 200 mg tablets P.M.**
60 – 74
1000 mg/day
2 x 200 mg tablets A.M.**
3 x 200 mg tablets P.M.***
≥75
1200 mg/day
3 x 200 mg tablets A.M.***
3 x 200 mg tablets P.M.***
2.2 Chronic Hepatitis C with HIV Coinfection
Adult Patients
The recommended dose for treatment of chronic hepatitis C in patients coinfected with HIV is peginterferon alfa-2a 180 mcg subcutaneous once weekly and Ribasphere 800 mg by mouth daily for a total duration of 48 weeks, regardless of HCV genotype.
2.3 Dose Modifications
Adult and Pediatric Patients
If severe adverse reactions or laboratory abnormalities develop during combination Ribasphere/peginterferon alfa-2a therapy, the dose should be modified or discontinued, if appropriate, until the adverse reactions abate or decrease in severity. If intolerance persists after dose adjustment, Ribasphere/peginterferon alfa-2a therapy should be discontinued. Table 3 provides guidelines for dose modifications and discontinuation based on the patient’s hemoglobin concentration and cardiac status.
Ribasphere should be administered with caution to patients with pre-existing cardiac disease. Patients should be assessed before commencement of therapy and should be appropriately monitored during therapy. If there is any deterioration of cardiovascular status, therapy should be stopped [see Warnings and Precautions (5.2)].
Table 3 Ribasphere Dose Modification Guidelines in Adults and Pediatrics
Body weight in kilograms (kg)
Laboratory Values
Hemoglobin <10 g/dL in patients with no cardiac disease, or
Decrease in hemoglobin of ≥2 g/dL during any 4 week period in patients with history of stable cardiac disease
Hemoglobin <8.5 g/dL in patients with no cardiac disease, or
Hemoglobin <12 g/dL despite 4 weeks at reduced dose in patients with history of stable cardiac disease
Adult Patients older than 18 years of age
Any weight
1 x 200 mg tablet A.M.
2 x 200 mg tablets or 1 x 400 mg tablet P.M.
Discontinue Ribasphere
Pediatric Patients 5 to 18 years of age
23 – 33 kg
1 x 200 mg tablet A.M.
Discontinue Ribasphere
34 – 46 kg
1 x 200 mg tablet A.M.
1 x 200 mg tablet P.M.
47 – 59 kg
1 x 200 mg tablet A.M.
1 x 200 mg tablet P.M.
60 – 74 kg
1 x 200 mg tablet A.M.
2 x 200 mg tablets P.M. or 1 x 400 mg tablet P.M.
≥75 kg
1 x 200 mg tablet A.M.
2 x 200 mg tablets P.M. or 1 x 400 mg tablet P.M.
The guidelines for Ribasphere dose modifications outlined in this table also apply to laboratory abnormalities or adverse reactions other than decreases in hemoglobin values.
Adult Patients
Once Ribasphere has been withheld due to either a laboratory abnormality or clinical adverse reaction, an attempt may be made to restart Ribasphere at 600 mg daily and further increase the dose to 800 mg daily. However, it is not recommended that Ribasphere be increased to the original assigned dose (1000 mg to 1200 mg).
Pediatric Patients
Upon resolution of a laboratory abnormality or clinical adverse reaction, an increase in Ribasphere dose to the original dose may be attempted depending upon the physician’s judgment. If Ribasphere has been withheld due to a laboratory abnormality or clinical adverse reaction, an attempt may be made to restart Ribasphere at one-half the full dose.
2.4 Renal Impairment
The total daily dose of Ribasphere should be reduced for patients with creatinine clearance less than or equal to 50 mL/min; and the weekly dose of peginterferon alfa-2a should be reduced for creatinine clearance less than 30 mL/min as follows in Table 4 [see Use in Specific Populations (8.7), Pharmacokinetics (12.3), and Peginterferon alfa-2a Package Insert].
Table 4 Dosage Modification for Renal Impairment
Creatinine
Clearance
Peginterferon alfa-2a Dose
(once weekly)
Ribasphere Dose (daily)
30 to 50 mL/min
180 mcg
Alternating doses, 200 mg and 400 mg every other day
Less than 30 mL/min
135 mcg
200 mg daily
Hemodialysis
135 mcg
200 mg daily
The dose of Ribasphere should not be further modified in patients with renal impairment. If severe adverse reactions or laboratory abnormalities develop, Ribasphere should be discontinued, if appropriate, until the adverse reactions abate or decrease in severity. If intolerance persists after restarting Ribasphere, Ribasphere/peginterferon alfa-2a therapy should be discontinued.
No data are available for pediatric subjects with renal impairment.
2.5 Discontinuation of Dosing
Discontinuation of peginterferon alfa-2a/Ribasphere therapy should be considered if the patient has failed to demonstrate at least a 2 log10 reduction from baseline in HCV RNA by 12 weeks of therapy, or undetectable HCV RNA levels after 24 weeks of therapy.
Peginterferon alfa-2a/Ribasphere therapy should be discontinued in patients who develop hepatic decompensation during treatment [see Warnings and Precautions (5.3)].