interferon [IFN]-alfa 2b (Intron A)

Introduction

Interferon alpha-2B. Tradename: Intron-A.

Indications

• chronic hepatitis B & hepatitis C
• acute hepatitis C infection
• malignant melanoma
• induction of remission for hairy cell leukemia
• treatment of AIDS-related Kaposi's sarcoma
• condyloma accuminata
• carcinoid syndrome
• follicular lymphoma
• mycosis fungoides-Sezary syndrome
• cutaneous T-cell lymphoma
• multiple myeloma
• chronic myeloid leukemia
  • Philadelphia chromosome-positive CML
• laryngeal papillomatosis
• hemangioma
• bladder cancer

Contraindications

Pregnancy category C

Safety in lactation ?

Dosage

• acute hepatitis C:
  • 5 million units daily for 4 weeks, then
  • 3 times weekly for 20 weeks
• chronic hepatitis C:
  • optimal dose has not been established
  • recommended dose in 3 million units IM/SC 3 times/week
  • maximum reduction in ALT seen in 8-12 weeks
  • therapy should continue for at least 6 months, preferably 12 months
• melanoma (use only 50 million IU/mL vials)
  • induction:
    • 20 million IU/m2 Monday-Friday as an IV infusion
    • continued for 4 weeks
  • maintenance
    • 10 million IU/m2 SC 3 times/week for 48 weeks Powder for injection, lyophilized:
      • 3, 5, 10, 18, 25, 50 million units Syringe: 3 & 5 million units

Pharmacokinetics

• filtered by renal tubules
• proteolytic degradation during renal tubular reabsorption

Monitor

• every 6 months
  • complete blood count (CBC)
  • electrolytes, BUN & serum creatinine
  • liver function tests
  • serum TSH
• electrocardiogram in patients with cardiac disease or in advanced stage of cancer

Adverse effects

• common (> 10%)
  • anemia
  • leukopenia
  • flu-like syndrome
  • skin rash
  • diarrhea
  • dizziness
  • fatigue
  • dry mouth
  • thrombocytopenia
  • metallic taste
  • anorexia
  • nausea/vomiting
• less common (1-10%)
  • hepatotoxicity, dry skin, diaphoresis, leg cramps, blurred vision, neurotoxicity, peripheral neuropathy, stomatitis, alopecia
• uncommon (< 1%)
  • cardiotoxicity, hypothyroidism, weight loss, arrhythmias, hypotension, nasal congestion, edema, ECG abnormalities, confusion, sensory neuropathy, fever/chills/rigors, headache, anemia, thrombocytopenia, increased serum transaminases, myalgias, arthralgias, proteinuria, hyperuricemia, renal insufficiency, cough, chest pain, neutralizing antibodies
• other
  • gingivitis
  • burning at the site of injection
  • depression (SSRI may be of benefit)

Drug interactions

• antineoplastic agents: additive or synergistic myelosuppressive effects
• may inhibit metabolism of agents metabolized by cyt P450 system
• acyclovir: possible synergistic effect
• zidovudine (AZT): possible additive myelosuppression
• theophylline clearance may be decreased
• vidarabine may increase neurotoxicity
• paroxetine in combination may increase risk of retinal hemorrhage

• drug interaction(s) of methotrexate with biological response modifier

Mechanism of action

• consists of at least 23 proteins & glycoproteins
• complex antiviral, antineoplastic & immunomodulating activity

More general terms

• biological response modifier
• interferon-alfa

More specific terms

• peginterferon alfa 2b (Pegintron)

Component of

• IFN-alpha 2b/ribavirin (Rebetron)