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Intron A

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Intron A

Intron A

INDICATIONS

Hairy Cell Leukemia

INTRON® A is indicated for the treatment of patients 18 years of age or older with hairy cell leukemia.

Malignant Melanoma

INTRON A is indicated as adjuvant to surgical treatment in patients 18 years of age or older with malignant melanoma who are free of disease but at high risk for systemic recurrence, within 56 days of surgery.

Follicular Lymphoma

INTRON A is indicated for the initial treatment of clinically aggressive (see CLINICAL PHARMACOLOGY) follicular Non-Hodgkin's Lymphoma in conjunction with anthracycline-containing combination chemotherapy in patients 18 years of age or older. Efficacy of INTRON A therapy in patients with low-grade, lowtumor burden follicular Non-Hodgkin's Lymphoma has not been demonstrated.

Condylomata Acuminata

INTRON A is indicated for intralesional treatment of selected patients 18 years of age or older with condylomata acuminata involving external surfaces of the genital and perianal areas (see DOSAGE AND ADMINISTRATION).

The use of this product in adolescents has not been studied.

AIDS-Related Kaposi's Sarcoma

INTRON A is indicated for the treatment of selected patients 18 years of age or older with AIDS-Related Kaposi's Sarcoma. The likelihood of response to INTRON A therapy is greater in patients who are without systemic symptoms, who have limited lymphadenopathy and who have a relatively intact immune system as indicated by total CD4 count.

Chronic Hepatitis C

INTRON A is indicated for the treatment of chronic hepatitis C in patients 18 years of age or older with compensated liver disease who have a history of blood or blood-product exposure and/or are HCV antibody positive. Studies in these patients demonstrated that INTRON A therapy can produce clinically meaningful effects on this disease, manifested by normalization of serum alanine aminotransferase (ALT) and reduction in liver necrosis and degeneration.

A liver biopsy should be performed to establish the diagnosis of chronic hepatitis. Patients should be tested for the presence of antibody to HCV. Patients with other causes of chronic hepatitis, including autoimmune hepatitis, should be excluded. Prior to initiation of INTRON A therapy, the physician should establish that the patient has compensated liver disease. The following patient entrance criteria for compensated liver disease were used in the clinical studies and should be considered before INTRON A treatment of patients with chronic hepatitis C:

  • No history of hepatic encephalopathy, variceal bleeding, ascites, or other clinical signs of decompensation
  • Bilirubin : Less than or equal to 2 mg/dL
  • Albumin : Stable and within normal limits
  • Prothrombin Time : Less than 3 seconds prolonged
  • WBC : Greater than or equal to 3000/mm³
  • Platelets : Greater than or equal to 70,000/mm³

Serum creatinine should be normal or near normal.

Prior to initiation of INTRON A therapy, CBC and platelet counts should be evaluated in order to establish baselines for monitoring potential toxicity. These tests should be repeated at Weeks 1 and 2 following initiation of INTRON A therapy, and monthly thereafter. Serum ALT should be evaluated at approximately 3-month intervals to assess response to treatment (see DOSAGE AND ADMINISTRATION).

Patients with preexisting thyroid abnormalities may be treated if thyroidstimulating hormone (TSH) levels can be maintained in the normal range by medication. TSH levels must be within normal limits upon initiation of INTRON A treatment and TSH testing should be repeated at 3 and 6 months (see PRECAUTIONS, Laboratory Tests).

INTRON A in combination with REBETOL® is indicated for the treatment of chronic hepatitis C in patients 3 years of age and older with compensated liver disease previously untreated with alpha interferon therapy and in patients 18 years of age and older who have relapsed following alpha interferon therapy. See REBETOL prescribing information for additional information.

Chronic Hepatitis B

INTRON A is indicated for the treatment of chronic hepatitis B in patients 1 year of age or older with compensated liver disease. Patients who have been serum HBsAg positive for at least 6 months and have evidence of HBV replication (serum HBeAg positive) with elevated serum ALT are candidates for treatment. Studies in these patients demonstrated that INTRON A therapy can produce virologic remission of this disease (loss of serum HBeAg) and normalization of serum aminotransferases. INTRON A therapy resulted in the loss of serum HBsAg in some responding patients.

Prior to initiation of INTRON A therapy, it is recommended that a liver biopsy be performed to establish the presence of chronic hepatitis and the extent of liver damage. The physician should establish that the patient has compensated liver disease. The following patient entrance criteria for compensated liver disease were used in the clinical studies and should be considered before INTRON A treatment of patients with chronic hepatitis B:

  • No history of hepatic encephalopathy, variceal bleeding, ascites, or other signs of clinical decompensation
  • Bilirubin : Normal
  • Albumin : Stable and within normal limits
  • Prothrombin Time : Adults less than 3 seconds prolonged
    Pediatrics less than or equal to 2 seconds prolonged
  • WBC : Greater than or equal to 4000/mm³
  • Platelets : Adults greater than or equal to 100,000/mm³
    Pediatrics greater than or equal to 150,000/mm³

Patients with causes of chronic hepatitis other than chronic hepatitis B or chronic hepatitis C should not be treated with INTRON A. CBC and platelet counts should be evaluated prior to initiation of INTRON A therapy in order to establish baselines for monitoring potential toxicity. These tests should be repeated at treatment Weeks 1, 2, 4, 8, 12, and 16. Liver function tests, including serum ALT, albumin, and bilirubin, should be evaluated at treatment Weeks 1, 2, 4, 8, 12, and 16. HBeAg, HBsAg, and ALT should be evaluated at the end of therapy, as well as 3- and 6-months posttherapy, since patients may become virologic responders during the 6-month period following the end of treatment. In clinical studies in adults, 39% (15/38) of responding patients lost HBeAg 1 to 6 months following the end of INTRON A therapy. Of responding patients who lost HBsAg, 58% (7/12) did so 1 to 6 months post-treatment.

A transient increase in ALT greater than or equal to 2 times baseline value (flare) can occur during INTRON A therapy for chronic hepatitis B. In clinical trials in adults and pediatrics, this flare generally occurred 8 to 12 weeks after initiation of therapy and was more frequent in responders (adults 63%, 24/38; pediatrics 59%, 10/17) than in nonresponders (adults 27%, 13/48; pediatrics 35%, 19/55). However, in adults and pediatrics, elevations in bilirubin greater than or equal to 3 mg/dL (greater than or equal to 2 times ULN) occurred infrequently (adults 2%, 2/86; pediatrics 3%, 2/72) during therapy. When ALT flare occurs, in general, INTRON A therapy should be continued unless signs and symptoms of liver failure are observed. During ALT flare, clinical symptomatology and liver function tests including ALT, prothrombin time, alkaline phosphatase, albumin, and bilirubin, should be monitored at approximately 2-week intervals (see WARNINGS).

DOSAGE AND ADMINISTRATION

General

IMPORTANT: INTRON® A is supplied as 1) Powder for Injection/Reconstitution; 2) Solution for Injection in Vials. Not all dosage forms and strengths are appropriate for some indications. It is important that you carefully read the instructions below for the indication you are treating to ensure you are using an appropriate dosage form and strength.

To enhance the tolerability of INTRON A, injections should be administered in the evening when possible.

To reduce the incidence of certain adverse reactions, acetaminophen may be administered at the time of injection.

The solution should be allowed to come to room temperature before using.

Hairy Cell Leukemia

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose for the treatment of hairy cell leukemia is 2 million IU/m² administered intramuscularly or subcutaneously 3 times a week for up to 6 months. Patients with platelet counts of less than 50,000/mm³ should not be administered INTRON A intramuscularly, but instead by subcutaneous administration. Patients who are responding to therapy may benefit from continued treatment.

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL IM, SC N/A
Solution 18 MIU multidose 6 MIU/mL IM, SC N/A
Solution 25 MIU multidose 10 MIU/mL IM, SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

If severe adverse reactions develop, the dosage should be modified (50% reduction) or therapy should be temporarily withheld until the adverse reactions abate and then resume at 50% (1 MIU/m² TIW).

  • If severe adverse reactions persist or recur following dosage adjustment, INTRON A should be permanently discontinued.
  • INTRON A should be discontinued for progressive disease or failure to respond after six months of treatment.
  • Malignant Melanoma (see DOSAGE AND ADMINISTRATION, General)

INTRON A adjuvant treatment of malignant melanoma is given in two phases, induction and maintenance.

Induction Recommended Dose

The recommended daily dose of INTRON A in induction is 20 million IU/m² as an intravenous infusion, over 20 minutes, 5 consecutive days per week, for 4 weeks (see Dose Adjustment below).

Dosage Forms for This Indication

Dosage Form Concentration Route
Powder 10 MIU 10 MIU/mL IV
Powder 18 MIU 18 MIU/mL IV
Powder 50 MIU 50 MIU/mL IV

NOTE: INTRON A Solution for Injection in vials is NOT recommended for intravenous administration and should not be used for the induction phase of malignant melanoma.

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

NOTE: Regular laboratory testing should be performed to monitor laboratory abnormalities for the purpose of dose modifications (see PRECAUTIONS, Laboratory Tests).

  • INTRON A should be withheld for severe adverse reactions, including granulocyte counts greater than 250/mm³ but less than 500/mm³ or SGPT/SGOT greater than 5- 10x upper limit of normal, until adverse reactions abate. INTRON A treatment should be restarted at 50% of the previous dose.
  • INTRON A should be permanently discontinued for:
    • Toxicity that does not abate after withholding INTRON A
    • Severe adverse reactions which recur in patients receiving reduced doses of INTRON A
    • Granulocyte count less than 250/mm³ or SGPT/SGOT of greater than 10x upper limit of normal
Maintenance Recommended Dose

The recommended dose of INTRON A for maintenance is 10 million IU/m² as a subcutaneous injection three times per week for 48 weeks (see Dose Adjustment below).

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose)* 10 MIU/mL SC N/A
Powder 18 MIU (single dose)** 18 MIU/mL SC N/A
Solution 18 MIU multidose 6 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A
*Patients receiving 50% dose reduction only
**Patients receiving full dose only

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

NOTE: Regular laboratory testing should be performed to monitor laboratory abnormalities for the purpose of dose modifications (see PRECAUTIONS, Laboratory Tests).

  • INTRON A should be withheld for severe adverse reactions, including granulocyte counts greater than 250/mm³ but less than 500/mm³ or SGPT/SGOT greater than 5- 10x upper limit of normal, until adverse reactions abate. INTRON A treatment should be restarted at 50% of the previous dose.
  • INTRON A should be permanently discontinued for:
    • Toxicity that does not abate after withholding INTRON A
    • Severe adverse reactions which recur in patients receiving reduced doses of INTRON A
    • Granulocyte count less than 250/mm³ or SGPT/SGOT of greater than 10x upper limit of normal
Follicular Lymphoma

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose of INTRON A for the treatment of follicular lymphoma is 5 million IU subcutaneously three times per week for up to 18 months in conjunction with anthracycline-containing chemotherapy regimen and following completion of the chemotherapy regimen.

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL SC N/A
Solution 18 MIU multidose 6 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment
  • Doses of myelosuppressive drugs were reduced by 25% from a full-dose CHOP regimen, and cycle length increased by 33% (e.g., from 21 to 28 days) when alpha interferon was added to the regimen.
  • Delay chemotherapy cycle if neutrophil count was less than 1500/mm³ or platelet count was less than 75,000/mm³.
  • INTRON A should be permanently discontinued if SGOT exceeds greater than 5x the upper limit of normal or serum creatinine greater than 2.0 mg/dL (see WARNINGS).
  • Administration of INTRON A therapy should be withheld for a neutrophil count less than 1000/mm³, or a platelet count less than 50,000/mm³.
  • INTRON A dose should be reduced by 50% (2.5 MIU TIW) for a neutrophil count greater than 1000/mm³, but less than 1500/mm³. The INTRON A dose may be reescalated to the starting dose (5 million IU TIW) after resolution of hematologic toxicity (ANC greater than 1500/mm³).
Condylomata Acuminata

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose is 1.0 million IU per lesion in a maximum of 5 lesions in a single course. The lesions should be injected three times weekly on alternate days for 3 weeks. An additional course may be administered at 12 to 16 weeks.

Dosage Forms for This Indication

Dosage Form Concentration
Powder 10 MIU (single dose) 10 MIU/mL
Solution 25 MIU multidose 10 MIU/mL

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

NOTE: Do not use the following formulations for this indication:

  • the 18 million or 50 million IU Powder for Injection
  • the 18 million IU multidose INTRON A Solution for Injection

Dose Adjustment: None

Technique for Injection: The injection should be administered intralesionally using a Tuberculin or similar syringe and a 25- to 30-gauge needle. The needle should be directed at the center of the base of the wart and at an angle almost parallel to the plane of the skin (approximately that in the commonly used PPD test). This will deliver the interferon to the dermal core of the lesion, infiltrating the lesion and causing a small wheal. Care should be taken not to go beneath the lesion too deeply; subcutaneous injection should be avoided, since this area is below the base of the lesion. Do not inject too superficially since this will result in possible leakage, infiltrating only the keratinized layer and not the dermal core.

AIDS-Related Kaposi's Sarcoma

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose of INTRON A for Kaposi's Sarcoma is 30 million IU/m²/dose administered subcutaneously or intramuscularly three times a week until disease progression or maximal response has been achieved after 16 weeks of treatment. Dose reduction is frequently required (see Dose Adjustment below).

Dosage Forms for This Indication

Dosage Form Concentration Route
Powder 50 MIU 50 MIU/mL IM, SC

NOTE: INTRON A Solution for Injection in vials should NOT be used for AIDSRelated Kaposi's Sarcoma.

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment

  • INTRON A dose should be reduced by 50% or withheld for severe adverse reactions.
  • INTRON A may be resumed at a reduced dose if severe adverse reactions abate with interruption of dosing.
  • INTRON A should be permanently discontinued if severe adverse reactions persist or if they recur in patients receiving a reduced dose.
Chronic Hepatitis C

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose of INTRON A for the treatment of chronic hepatitis C is 3 million IU three times a week (TIW) administered subcutaneously or intramuscularly. In patients tolerating therapy with normalization of ALT at 16 weeks of treatment, INTRON A therapy should be extended to 18 to 24 months (72 to 96 weeks) at 3 million IU TIW to improve the sustained response rate (see CLINICAL PHARMACOLOGY, Chronic Hepatitis C). Patients who do not normalize their ALTs or have persistently high levels of HCV RNA after 16 weeks of therapy rarely achieve a sustained response with extension of treatment. Consideration should be given to discontinuing these patients from therapy.

When INTRON A is administered in combination with REBETOL®, patients with impaired renal function and/or those over the age of 50 should be carefully monitored with respect to the development of anemia. See REBETOL prescribing information for dosing when used in combination with REBETOL for adults and pediatric patients.

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Solution 18 MIU multidose 6 MIU/mL IM, SC N/A

Dose Adjustment: If severe adverse reactions develop during INTRON A treatment, the dose should be modified (50% reduction) or therapy should be temporarily discontinued until the adverse reactions abate. If intolerance persists after dose adjustment, INTRON A therapy should be discontinued.

Chronic Hepatitis B

Adults

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose of INTRON A for the treatment of chronic hepatitis B is 30 to 35 million IU per week, administered subcutaneously or intramuscularly, either as 5 million IU daily (QD) or as 10 million IU three times a week (TIW) for 16 weeks.

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL IM, SC N/A
Solution 25 MIU multidose 10 MIU/mL IM, SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Chronic Hepatitis B

Pediatrics

(see DOSAGE AND ADMINISTRATION, General)

Dose: The recommended dose of INTRON A for the treatment of chronic hepatitis B is 3 million IU/m² three times a week (TIW) for the first week of therapy followed by dose escalation to 6 million IU/m² TIW (maximum of 10 million IU TIW) administered subcutaneously for a total duration of 16 to 24 weeks.

Dosage Forms for This Indication

Dosage Form Concentration Route Fixed Doses
Powder 10 MIU (single dose) 10 MIU/mL SC N/A
Solution 25 MIU multidose 10 MIU/mL SC N/A

NOTE: INTRON A Powder for Injection does not contain a preservative. The vial must be discarded after reconstitution and withdrawal of a single dose.

Dose Adjustment: If severe adverse reactions or laboratory abnormalities develop during INTRON A therapy, the dose should be modified (50% reduction) or discontinued if appropriate, until the adverse reactions abate. If intolerance persists after dose adjustment, INTRON A therapy should be discontinued.

For patients with decreases in white blood cell, granulocyte or platelet counts, the following guidelines for dose modification should be followed:

INTRON A Dose White Blood Cell Count Granulocyte Count Platelet Count
Reduce 50% < 1.5 x 109/L < 0.75 x 109/L < 50 x 109/L
Permanently Discontinue < 1.0 x 109/L < 0.5 x 109/L < 25 x 109/L

INTRON A therapy was resumed at up to 100% of the initial dose when white blood cell, granulocyte, and/or platelet counts returned to normal or baseline values.

PREPARATION AND ADMINISTRATION Reconstitution of INTRON® A Powder for Injection The reconstituted solution is clear and colorless to light yellow. The INTRON A powder reconstituted with Sterile Water for Injection USP is a single-use vial and does not contain a preservative. DO NOT RE-ENTER VIAL AFTER WITHDRAWING THE DOSE. DISCARD UNUSED PORTION (see DOSAGE AND ADMINISTRATION). Once the dose from the single-dose vial has been withdrawn, the sterility of any remaining product can no longer be guaranteed. Pooling of unused portions of some medications has been linked to bacterial contamination and morbidity.

  • Intramuscular, Subcutaneous, or Intralesional Administration

Inject 1 mL Diluent (Sterile Water for Injection USP) for INTRON A into the INTRON A vial. Swirl gently to hasten complete dissolution of the powder. The appropriate INTRON A dose should then be withdrawn and injected intramuscularly, subcutaneously, or intralesionally (see Medication Guide for detailed instructions).

Please refer to the Medication Guide for detailed, step-by-step instructions on how to inject the INTRON A dose. After preparation and administration of the INTRON A injection, it is essential to follow the procedure for proper disposal of syringes and needles (see Medication Guide for detailed instructions).

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration.

  • Intravenous Infusion

The infusion solution should be prepared immediately prior to use. Based on the desired dose, the appropriate vial strength(s) of INTRON A should be reconstituted with the diluent provided. Inject 1 mL Diluent (Sterile Water for Injection USP) for INTRON A into the INTRON A vial. Swirl gently to hasten complete dissolution of the powder. The appropriate INTRON A dose should then be withdrawn and injected into a 100-mL bag of 0.9% Sodium Chloride Injection USP. The final concentration of INTRON A should not be less than 10 million IU/100 mL.

Please refer to the Medication Guide for detailed, step-by-step instructions on how to inject the INTRON A dose. After preparation and administration of INTRON A, it is essential to follow the procedure for proper disposal of syringes and needles.

INTRON A Solution for Injection in Vials INTRON A Solution for Injection is supplied in two multidose vials. The solutions for injection do not require reconstitution prior to administration; the solution is clear and colorless.

The appropriate dose should be withdrawn from the vial and injected intramuscularly, subcutaneously, or intralesionally.

INTRON A Solution for Injection is not recommended for intravenous administration.

Please refer to the Medication Guide for detailed, step-by-step instructions on how to inject the INTRON A dose. After preparation and administration of INTRON A, it is essential to follow the procedure for proper disposal of syringes and needles.

HOW SUPPLIED

INTRON® A Powder for Injection

INTRON A Powder for Injection, 10 million IU per vial and Diluent for INTRON A (Sterile Water for Injection USP) 1 mL per vial; boxes containing 1 INTRON A vial and 1 vial of INTRON A Diluent (NDC 0085-0571-02).

INTRON A Powder for Injection, 18 million IU per vial and Diluent for INTRON A (Sterile Water for Injection USP) 1 mL per vial; boxes containing 1 vial of INTRON A and 1 vial of INTRON A Diluent (NDC 0085-1110-01).

INTRON A Powder for Injection, 50 million IU per vial and Diluent for INTRON A (Sterile Water for Injection USP) 1 mL per vial; boxes containing 1 INTRON A vial and 1 vial of INTRON A Diluent (NDC 0085-0539-01).

INTRON A Solution for Injection in Vials

INTRON A Solution for Injection, 18 million IU multidose vial (22.8 million IU per 3.8 mL per vial); boxes containing 1 vial of INTRON A Solution for Injection (NDC 00851168- 01).

INTRON A Solution for Injection, 25 million IU multidose vial (32 million IU per 3.2 mL per vial); boxes containing 1 vial of INTRON A Solution for Injection (NDC 00851133- 01).

Storage

  • INTRON A Powder for Injection/Reconstitution
    INTRON A Powder for Injection should be stored in the refrigerator at 2° to 8°C (36°- 46°F). After reconstitution, the solution should be used immediately, but may be stored up to 24 hours at 2° to 8°C (36°-46°F). Throw away any medicine left in the vial after you withdraw 1 dose.
  • INTRON A Solution for Injection in Vials
    INTRON A Solution for Injection in vials should be stored in the refrigerator at 2° to 8°C (36°-46°F).
    INTRON A Solution for Injection should not be frozen and should be kept away from heat. Throw away any unused INTRON A Solution for Injection remaining in the vial after one month.

REFERENCES

4. Schiller J, et al. J Biol Response Mod. 1989;8:252-261.

11. Kauppila A, et al. Int J Cancer. 1982;29:291 -294.

Manufactured by: Schering Corporation, a subsidiary of Merck & Co., Inc. Whitehouse Station, NJ 08889 US. Rev. 04/2014

Last reviewed on RxList: 4/17/2014
This monograph has been modified to include the generic and brand name in many instances.

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