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Infergen Dosage

Generic name: Interferon alfacon-1 0.03mg in 1mL
Dosage form: injection
Drug class: Interferons

Medically reviewed by Drugs.com. Last updated on Dec 13, 2024.

INFERGEN Monotherapy Dosing

The recommended dose of INFERGEN monotherapy for the initial treatment of chronic HCV infection is 9 mcg administered three times a week as a single subcutaneous injection for 24 weeks.

The recommended dose of INFERGEN monotherapy for patients who tolerated previous interferon therapy and did not respond or relapsed following its discontinuation is 15 mcg administered three times a week as a single subcutaneous injection for up to 48 weeks. Patients who do not tolerate initial standard interferon therapy should not be treated with INFERGEN therapy 15 mcg three times a week.

Combination Treatment with INFERGEN/Ribavirin Dosing

The recommended dose of INFERGEN is 15 mcg daily administered as a single subcutaneous injection in combination with weight-based ribavirin at 1,000 mg - 1,200 mg (< 75 kg and ≥75 kg) orally in two divided doses for up to 48 weeks..

Ribavirin should be taken with food. INFERGEN/ribavirin should not be used in patients with creatinine clearance < 50 mL/min.

Dose Modifications

If a serious adverse reaction develops during the course of treatment discontinue or modify the dosage of INFERGEN and/or ribavirin until the adverse event abates or decreases in severity. If persistent or recurrent serious adverse events develop despite adequate dosage adjustment, discontinue treatment. Upon resolution or improvement of the adverse reaction, resuming INFERGEN and/or ribavirin may be considered.

INFERGEN Monotherapy Dose Modifications

Dose reduction to 7.5 mcg may be necessary following a serious adverse reaction. If serious adverse events continue to occur, dosing should be interrupted or discontinued as the efficacy of lower doses has not been established.

INFERGEN/Ribavirin Combination Therapy Dose Modifications

Stepwise dose reduction from 15 mcg to 9 mcg and from 9 mcg to 6 mcg may be necessary for serious adverse reactions.

Guidelines for INFERGEN/Ribavirin Dose Modifications

Tables 1, 2, and 3 provide guidelines for dose modifications and discontinuation of INFERGEN and/or ribavirin based on depression or laboratory parameters.

Table 1. Guidelines for Dose Modification or Discontinuation of INFERGEN and for Scheduling Visits for Patients with Depression
* See DSM-IV for definitions.

Depression Severity*

Initial Management

(4–8 Weeks)

Depression

Dose Modification

Visit Schedule

Remains Stable

Improves

Worsens

Mild

No change to INFERGEN dose or ribavirin dose.

Evaluate once weekly by visit and/or phone.

Continue weekly visit schedule.

Resume normal visit schedule.

(See moderate or severe depression)

Moderate

Decrease INFERGEN dose from 15 mcg to 9 mcg; or from 9 mcg to 6 mcg, no change to ribavirin dose.

Evaluate once weekly (office visit at least every other week).

Consider psychiatric consultation. Continue reduced dosing.

If symptoms improve and are stable for 4 weeks, may resume normal visit schedule. Continue reduced INFERGEN dosing or return to normal INFERGEN dose.

(See severe depression)

Severe

Discontinue INFERGEN and ribavirin permanently.

Not applicable.

Psychiatric therapy necessary.

Not applicable.

Not applicable.
Table 2. Guidelines for Dose Modification or Discontinuation of INFERGEN for Hematologic Toxicities

Laboratory Values

Action

ANC < 0.75 × 109/L

Reduce INFERGEN dose from 15 mcg to 9 mcg, or from 9 mcg to 6 mcg; maintain ribavirin dose at 1200 mg or 1000 mg.

ANC < 0.50 × 109/L

INFERGEN and ribavirin treatment should be suspended until ANC values return to more than 1000/mm3.

Platelet Count < 50 × 109/L

Reduce INFERGEN dose from 15 mcg to 9 mcg or from 9 mcg to 6 mcg; maintain ribavirin dose at 1200 mg or 1000 mg.

Platelet Count < 25 × 109/L

INFERGEN and ribavirin treatment should be discontinued.
Table 3. Guidelines for Dose Modification or Discontinuation of INFERGEN/Ribavirin for the Management of Anemia*
* For adult patients with a history of stable cardiac disease receiving INFERGEN in combination with ribavirin, the INFERGEN dose should be reduced from 15 mcg to 9 mcg or 9 mcg to 6 mcg and the ribavirin dose by 200 mg/day if a >2 g/dL decrease in hemoglobin is observed during any 4-week period. Both INFERGEN and ribavirin should be permanently discontinued if patients have hemoglobin levels <12 g/dL after this ribavirin dose reduction.
** 1st dose reduction of ribavirin is by 200 mg/day. 2nd dose reduction of ribavirin (if needed) is by an additional 200 mg/day.

Condition

INFERGEN

Ribavirin

Hgb <10 g/dL

History of Cardiac or Cerebrovascular Disease, reduce dose of INFERGEN

Adjust dose**

Hgb <8.5 g/dL

Permanently discontinue

Permanently discontinue

Renal Function: INFERGEN/ribavirin should not be used in patients with creatinine clearance <50 mL/min..

Discontinuation of Treatment

Patients who fail to achieve at least a 2 log10 drop at 12 weeks or undetectable HCV-RNA at week 24 are highly unlikely to achieve SVR and discontinuation of therapy should be considered.

Ribavirin should be discontinued in any patient who temporarily or permanently discontinues INFERGEN.

Preparation and Administration

Just prior to injection, INFERGEN may be allowed to reach room temperature.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration; if particulates or discoloration are observed, the vial should not be used.

If home use is determined to be desirable by the physician, instructions on appropriate use should be given by a healthcare professional. After administration of INFERGEN, it is essential to follow the procedure for proper disposal of syringes and needles..

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