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Peginterferon Beta-1a

Class: Immunomodulatory Agents
Chemical Name: 1-Ether with N-(3-hydroxy-2-methylpropyl)interferon β-1a (human) α-methyl-ω-hydroxy-poly(oxy-1,2-ethanediyl)
Molecular Formula: C913H1417N246O256PS7 [C2H4O]n
CAS Number: 1211327-92-2
Brands: Plegridy


A covalent conjugate of interferon beta-1a (recombinant DNA origin) and polyethylene glycol (PEG).1 Interferon beta-1a is an immunomodulatory agent.10 21

Uses for Peginterferon Beta-1a

Multiple Sclerosis (MS)

Management of relapsing forms of MS (e.g., relapsing-remitting MS [RRMS]).1 2 3

Peginterferon Beta-1a Dosage and Administration


  • To minimize risk of flu-like symptoms, may administer prophylactic or concurrent analgesics and/or antipyretics.1


Administer by sub-Q injection only.1

Sub-Q Administration

Administer by sub-Q injection every 14 days into abdomen, back of upper arm, or thigh.1 Rotate injection sites.1 (See Injection Site Reactions under Cautions.)

Commercially available as a single-dose prefilled injection pen or syringe.1 Instruct patients on proper techniques for self-administration.1 (See Advice to Patients.)

Prior to administration, allow prefilled injection pens and syringes to reach room temperature (about 30 minutes).1

For single-use only; discard after use.1



Multiple Sclerosis

Gradually titrate to recommended dosage of 125 mcg every 14 days according to schedule in Table 1.1

Table 1. Peginterferon Beta-1a Dosage Titration Schedule1



1 (first day of therapy)

63 mcg

15 (14 days later)

94 mcg

29 and every 14 days thereafter

125 mcg

The Plegridy or Plegridy Pen Starter Pack, which contains a 63 mcg prefilled injection pen or syringe, and a 94 mcg prefilled injection pen or syringe, is designed to be used during dosage titration.1

Special Populations

Hepatic Impairment

No specific dosage recommendations.1

Renal Impairment

Manufacturer makes no specific dosage recommendations;1 results of a pharmacokinetic study suggest dosage adjustment not required.8

Geriatric Patients

No specific dosage recommendations.1

Other Special Populations

Dosage adjustments based on body weight, gender, or age not required.1

Cautions for Peginterferon Beta-1a


  • Known hypersensitivity to natural or recombinant interferon beta or peginterferon, or any other ingredient in the formulation.1



Possible elevations in hepatic aminotransferase concentrations (ALT and AST) and hepatic injury.1

Hepatitis, autoimmune hepatitis, and rare cases of hepatic failure reported with interferon beta therapy.1 5 6

Monitor patients for hepatic injury.1 (See Advice to Patients.)

Depression and Suicide

Depression, suicidal ideation, and suicide attempts possible.1 5 6 If depression or other serious psychiatric symptoms occur, consider discontinuing therapy.1


Possible seizures; use with caution in patients with preexisting seizure disorders.1 5 6

Injection Site Reactions

Local injection site reactions (i.e., erythema, pain, pruritus, edema) are common following sub-Q administration; occurred in about 66% of patients in clinical studies.1 More severe injection site reactions, including necrosis, also reported.1

Whether to discontinue therapy following a single site of necrosis depends on extent of necrosis.1 If therapy is continued, avoid injections near affected site until lesion has fully healed.1 If multiple lesions occur, discontinue drug until healing occurs.1

Cardiovascular Effects

Possible congestive heart failure and cardiomyopathy;1 6 monitor patients with substantial cardiac disease for worsening of their condition during therapy.1

Hematologic Effects

Decreased peripheral blood cell counts in all cell lines, including rare pancytopenia and thrombocytopenia, reported with interferon beta therapy.1 5 6

Monitor CBCs, including differential and platelet counts, during therapy.1 In addition, monitor patients for infections, bleeding, and symptoms of anemia.1

Autoimmune Diseases

Autoimmune diseases, including idiopathic thrombocytopenic purpura (ITP), hyperthyroidism, hypothyroidism, and autoimmune hepatitis, reported.1

If a new autoimmune disorder develops, consider discontinuing therapy.1


Possible development of neutralizing antibodies to peginterferon beta-1a or PEG.1 Presence of anti-PEG antibodies does not appear to affect overall exposure or pharmacodynamic response to the drug.7

Sensitivity Reactions


Anaphylaxis and other serious allergic reactions (e.g., angioedema, urticaria) reported rarely.1 5 6

Discontinue therapy if a serious allergic reaction occurs.1 (See Contraindications under Cautions.)

Specific Populations


Category C.1

No adequate and well-controlled studies in pregnant women; use during pregnancy only when potential benefits justify possible risks to fetus.1

Animal reproduction studies not conducted to date with peginterferon beta-1a; however, studies using nonconjugated interferon beta in pregnant monkeys demonstrated some abortifacient activity, but no evidence of teratogenic or other adverse fetal effects.1 5 6


Not known whether peginterferon beta-1a is distributed into human milk.1 Use with caution in nursing women.1

Pediatric Use

Safety and efficacy not established in pediatric patients.1

Geriatric Use

Safety and efficacy not established in geriatric patients.1

Renal Impairment

Because of possibility of increased drug exposure, monitor patients with severe renal impairment for adverse effects.1 (See Absorption: Special Populations, under Pharmacokinetics.)

Systemic exposure not affected in patients with end-stage renal disease undergoing hemodialysis.1 8

Common Adverse Effects

Injection site erythema,1 flu-like symptoms,1 pyrexia,1 headache,1 myalgia,1 chills,1 injection site pain,1 asthenia,1 injection site pruritus,1 arthralgia.1

Interactions for Peginterferon Beta-1a

No formal drug interaction studies to date.1

Peginterferon Beta-1a Pharmacokinetics



Peak plasma concentrations occur 1–1.5 days following sub-Q administration.1 7

Special Populations

In patients with mild, moderate, or severe renal impairment, AUC increased by 30, 40, or 53%, respectively.1 8

Body weight, gender, or age does not appear to affect pharmacokinetics.1



Not known whether peginterferon beta-1a is distributed into milk.1



Not extensively metabolized in the liver.1

Elimination Route

Principally eliminated by renal excretion.1


Approximately 78 hours in patients with MS.1

Special Populations

Hemodialysis removes approximately 24% of a dose.1 8





Prefilled injection pens and syringes: 2–8°C in original carton to protect from light; do not freeze.1

May be stored at 2–25°C for up to 30 days; do not freeze.1 May be moved to and from refrigeration if necessary; however, total combined time out of refrigeration within temperature range of 2–25°C should not exceed 30 days.1


  • Biosynthetic (recombinant DNA origin) preparation of human interferon beta-1a covalently bound to PEG.1

  • Interferon beta-1a portion is identical to commercially available nonconjugated interferon beta-1a (Avonex).13 As a result of PEG conjugation, clearance is reduced, systemic exposure is increased, and plasma half-life is prolonged, allowing for less frequent dosing compared with nonconjugated interferon.1 12 13

  • Mechanism of action in the treatment of MS not fully elucidated;1 however, a variety of immunomodulatory effects have been described with interferon beta-1a.10 21

Advice to Patients

  • Importance of patients reading the manufacturer's patient information (medication guide) and instructions for use before initiating treatment and each time the prescription is refilled.1 9

  • Importance of taking peginterferon beta-1a exactly as prescribed.9 Advise patients not to change their dosage or administration schedule without consulting their clinician.1 9

  • Importance of instructing patients regarding proper methods of preparation and self injection of peginterferon beta-1a, including the use of aseptic technique.1 Importance of providing instructions on the appropriate use, storage, and disposal of injection pens and needles.1

  • Risk of hepatotoxicity; importance of advising patients to immediately inform their clinician if they experience any symptoms of liver injury (e.g., jaundice, nausea, loss of appetite, fatigue, unusual bleeding, confusion, somnolence, dark-colored urine, pale stools).1 9

  • Risk of developing depression and suicidal ideation.1 9 Importance of patients immediately notifying their clinician if symptoms of depression or suicidal ideation occur.1 9

  • Risk of seizures.1 9 Importance of patients immediately informing their clinician if a seizure occurs during therapy.1

  • Risk of hypersensitivity reactions, including anaphylaxis.1 9 Importance of advising patients to seek immediate medical attention if any symptoms of hypersensitivity occur.1

  • Risk of injection site reactions, including necrosis.1 9 Importance of patients immediately informing their clinician if any blue-black discoloration, swelling, or fluid drainage occurs in conjunction with skin breakage at the injection site.1

  • Importance of informing patients that worsening of heart disease has occurred with interferon beta-1a therapy.1 9 Importance of informing patients of the symptoms of worsening heart failure and to immediately report any such symptoms to their clinician.1 9

  • Importance of informing patients that flu-like symptoms (e.g., headache, muscle and joint aches, fever, chills, fatigue) are common following initiation of therapy with peginterferon beta-1a, and that concurrent administration of analgesics and/or antipyretics may minimize these symptoms.1 9

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.1 9

  • Importance of patients informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses (e.g., liver disease, psychiatric disorders, seizures).1 9

  • Importance of informing patients of other important precautionary information.1 (See Cautions.)


Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

Peginterferon Beta-1a


Dosage Forms


Brand Names



Injection, for subcutaneous use

125 mcg/0.5 mL

Plegridy (available as single-dose prefilled syringes)

Biogen Idec

Plegridy Pen (available as single-dose prefilled pens)

Biogen Idec

Kit, injection, for subcutaneous use

1 syringe, 63 mcg/0.5 mL

1 syringe, 94 mcg/0.5 mL

Plegridy Starter Pack (available as single-dose prefilled syringes)

Biogen Idec

1 injection pen, 63 mcg/0.5 mL

1 injection pen, 94 mcg/0.5 mL

Plegridy Pen Starter Pack (available as single-dose prefilled pens)

Biogen Idec

AHFS DI Essentials. © Copyright, 2016, American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland 20814.

Date modified: February 08, 2016
Last reviewed: December 11, 2015
Date published: December 11, 2015


1. Biogen Idec Inc. Plegridy (peginterferon beta-1a) injection for subcutaneous use prescribing information. Cambridge, MA; 2014 Aug.

2. Calabresi PA, Kieseier BC, Arnold DL et al. Pegylated interferon β-1a for relapsing-remitting multiple sclerosis (ADVANCE): a randomised, phase 3, double-blind study. Lancet Neurol. 2014; 13:657-65. [PubMed 24794721]

3. Kieseier BC, Arnold DL, Balcer LJ et al. Peginterferon beta-1a in multiple sclerosis: 2-year results from ADVANCE. Mult Scler. 2015; 21:1025-35. [PubMed 25432952]

4. Arnold DL, Calabresi PA, Kieseier BC et al. Effect of peginterferon beta-1a on MRI measures and achieving no evidence of disease activity: results from a randomized controlled trial in relapsing-remitting multiple sclerosis. BMC Neurol. 2014; 14:240. [PubMed 25551571]

5. Serono, Inc. Rebif (interferon beta-1a) for subcutaneous injection prescribing information. Rockland, MA; 2015 Mar.

6. Biogen Idec Inc. Avonex (interferon beta-1a) for intramuscular injection prescribing information. Cambridge, MA; 2014 Aug.

7. Hu X, Cui Y, White J et al. Pharmacokinetics and pharmacodynamics of peginterferon beta-1a in patients with relapsing-remitting multiple sclerosis in the randomized ADVANCE study. Br J Clin Pharmacol. 2015; 79:514-22. [PubMed 25265472]

8. Hu X, Seddighzadeh A, Stecher S et al. Pharmacokinetics, pharmacodynamics, and safety of peginterferon beta-1a in subjects with normal or impaired renal function. J Clin Pharmacol. 2015; 55:179-88. [PubMed 25187030]

9. Biogen Idec Inc. Plegridy (peginterferon beta-1a) injection for subcutaneous use medication guide. Cambridge, MA; 2014 Aug.

10. Kasper LH, Reder AT. Immunomodulatory activity of interferon-beta. Ann Clin Transl Neurol. 2014; 1:622-31. [PubMed 25356432]

11. Hoy SM. Peginterferon beta-1a: a review of its use in patients with relapsing-remitting multiple sclerosis. CNS Drugs. 2015; 29:171-9. [PubMed 25666445]

12. Hu X, Miller L, Richman S et al. A novel PEGylated interferon beta-1a for multiple sclerosis: safety, pharmacology, and biology. J Clin Pharmacol. 2012; 52:798-808. [PubMed 21680782]

13. US Food and Drug Administration. Summary Review for Regulatory Action: BLA# 1254499. From FDA website.

21. Goodin DS, Frohman EM, Garmany GP et al. Disease modifying therapies in multiple sclerosis: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology and the MS Council for Clinical Practice Guidelines. Neurology. 2002; 58:169-78. [PubMed 11805241]