interferon [IFN]-alfa 2a (Roferon-A)

Introduction

Tradename: Roferon-A.

Indications

• hairy cell leukemia
• AIDS-related Kaposi's sarcoma
• chronic phase of Philadelpha chromosome positive CML
• bladder cancer
• mycosis fungoides Sezary syndrome
• cutaneous T-cell lymphoma
• multiple myeloma
• carcinoid syndrome
• chronic hepatitis B, chronic hepatitis C
• pulmonary capillary hemangiomatosis
• hemangioma

Contraindications

Warnings:

• use with caution in patients with:
  • seizure disorders
  • compromised CNS dysfunction
  • pre-existing cardiac disease
  • severe hepatic or renal insufficiency
  • myelosuppression
• safety & efficacy in children < 18 years of age is not established
• mental status changes may occur while on therapy

Pregnancy category C

Safety in lactation ?

Dosage

• refer to individual protocols
• stable for 24 hours under refrigeration after reconstitution with sterile water
• solution reconstituted with diluent is stable for one month when refrigerated
• do not change brands as changes in dosage may result

Injection:

• 3 million units/mL (1 mL)
• 6 million units/mL (3 mL)
• 9 million units/mL (0.9 mL)
• 36 million units/mL (1 mL)

Powder for injection: 6 million units/mL when reconstituted

Pharmacokinetics

• bioavailability 90% SC
• peak serum concentration in 6-8 hours SC
• elimination 1/2life of 4-8 hours
• filtered by renal tubules
• volume of distribution 31 L (320-720 L in leukemia patients receiving infusions)
• proteolytic degradation during renal tubular reabsorption

Monitor

• complete blood count (CBC)
• electrolytes, BUN & creatinine
• liver function tests
• electrocardiogram in patients with cardiac disease or in advanced stage of cancer
• baseline chest x-ray

Adverse effects

• not common (1-10%)
  • hepatotoxicity, dry skin, diaphoresis, leg cramps, blurred vision, neurotoxicity, peripheral neuropathy, stomatitis, alopecia
• uncommon (< 10%)
  • 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

Drug interactions

• acyclovir: possible synergistic effect
• zidovudine (AZT): possible additive myelosuppression
• theophylline clearance may be decreased
• vinblastine
  • possible increased interferon toxicity
  • increased incidence of paresthesias
• vidarabine may increase neurotoxicity

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

More general terms

• biological response modifier
• interferon-alfa

More specific terms

• peginterferon alfa 2a (Pegasys)