What is PEG?

PEG is polyethylene glycol, which is a synthetic polymer manufactured from ethylene oxide.1

Learn more about pegylation

What is pegylation?

Pegylation involves the attachment of a polyethylene glycol (PEG) polymer chain to a molecule. This attachment increases molecular mass and contributes to a subsequent reduction in renal clearance.2

Learn more about pegylation

How effective is high-dose, low-frequency PLEGRIDY?

In the ADVANCE trial, the efficacy of PLEGRIDY was assessed from the placebo-controlled first year (48 weeks) of a 2-year, randomized, double-blind clinical study, including 1,512 patients with relapsing forms of MS.2,3

  • PLEGRIDY significantly reduced the proportion of patients with disability progression
  • PLEGRIDY significantly reduced relapse rates
  • PLEGRIDY significantly reduced the number of new and newly enlarging T2 and Gd-enhancing MRI lesions

Learn more about the efficacy of high-dose, low-frequency PLEGRIDY

How do patients take high-dose, low-frequency PLEGRIDY? Should titration be used for patients starting treatment with PLEGRIDY?

PLEGRIDY is injected subcutaneously at a recommended dosage of 125 micrograms once every 14 days. Since titration is recommended, patients should start treatment with 63 micrograms on day 1. On day 15 (14 days later), the dose should be increased to 94 micrograms. The full dose of 125 micrograms is reached on day 29 (after another 14 days). Patients continue with the full dose (125 micrograms) every 14 days thereafter. Furthermore, patients have options with the PLEGRIDY PEN and prefilled syringe.2

Nurse Educators, available through the Above MS™ program from Biogen, can offer additional injection and product education through one-on-one guidance—at no cost to your patients.

See additional dosing information for high-dose, low-frequency PLEGRIDY

Is titration available with the PLEGRIDY PEN?

Yes. Patients should titrate using the PLEGRIDY PEN or prefilled syringe. The PLEGRIDY Starter Pack contains the 63 mcg and 94 mcg color-coded doses in both administration options.2

Learn more about the PLEGRIDY Starter Pack

What areas of the body should patients use when injecting high-dose, low-frequency PLEGRIDY?

Patients should inject in their thigh, abdomen, or back of their upper arm. Patients should also be advised to rotate the injection site, avoiding 2 or more consecutive injections in the same site in order to minimize injection site reactions.4

Learn more about the Instructions for Use

What is the pH of the PLEGRIDY formulation?

The pH of PLEGRIDY is approximately 4.8.2

How should PLEGRIDY be stored, and is it stable at room temperature?

PLEGRIDY should be stored in a refrigerator between 2°C to 8°C (36°F to 46°F). Do not freeze. If refrigeration is unavailable, PLEGRIDY may be stored between 2°C to 25°C (36°F to 77°F) for a period up to 30 days, protected from light. The total combined time out of refrigeration within this temperature range should not exceed 30 days.2

What are the common adverse reactions associated with high-dose, low-frequency PLEGRIDY?

The most common adverse reactions (incidence more than 10% and at least 2% more frequent on PLEGRIDY than on placebo) associated with PLEGRIDY treatment are injection site erythema, influenza‐like illness, pyrexia, headache, myalgia, chills, injection site pain, asthenia, injection site pruritus, and arthralgia.2

See additional safety information for PLEGRIDY
See additional tolerability information for PLEGRIDY

How can patients get PLEGRIDY?

PLEGRIDY is available through a limited distribution model, providing access through a network of preferred specialty pharmacies. This allows for every patient with relapsing MS to receive a consistent level of pharmacy services that facilitates access to PLEGRIDY. PLEGRIDY Specialty Pharmacy Network comprises 2 subgroups of specialty pharmacies: 

  1. PLEGRIDY Pharmacy Network: Traditional specialty pharmacies, including national and regional specialty pharmacies that may be payer-owned, pharmacy benefit manager (PBM)-owned, or independent.
  2. PLEGRIDY Alternate Care Pharmacy Network: Specialty pharmacies that are typically part of integrated healthcare systems, and provide specialty pharmaceutical services to patients through outpatient facilities.

Learn more about specialty pharmacies

What patient support services are available?

The Above MS™ program from Biogen offers helpful services for you and your practice to support your patients.

For your practice:

  • Benefits investigation to help determine the best coverage options for patients
  • Insurance counseling for the uninsured and underinsured
  • Tools for navigating the US healthcare reform law
  • Nurse Educator reporting on patient progress between office visits (if applicable)

For your patients:

  • A variety of financial and insurance support services
  • 24/7 phone assistance from Nurse Educators. Support is available in Spanish
  • Support finding assistance from charitable organizations
  • Information about Biogen’s relapsing MS treatment options
  • Tips for managing common side effects once prescribed treatment
  • Disease-state education

Learn more about Above MS

Is additional injection training available for patients taking high-dose, low-frequency PLEGRIDY?

Whether your patients are just starting treatment or have been on treatment for a while, Nurse Educators are available by phone 24/7 to provide extra support and to answer their questions. The Above MS™ program from Biogen also provides additional injection training for people taking an injectable Biogen treatment for relapsing MS. This may include a Nurse Educator visiting their home (if needed). Nurse Educators can be reached by calling 1-800-456-2255. Support is available in Spanish.

Learn more about Nurse Educators

Important Safety Information


  • PLEGRIDY® (peginterferon beta-1a) is contraindicated in patients with a history of hypersensitivity to natural or recombinant interferon beta or peginterferon, or any other component of the formulation


Hepatic Injury

  • Severe hepatic injury, including hepatitis, autoimmune hepatitis, and rare cases of severe hepatic failure, have been reported with interferon beta. Asymptomatic elevation of hepatic transaminases has also been reported, and in some patients has recurred upon rechallenge with interferon beta. Elevations in hepatic enzymes and hepatic injury have been observed with PLEGRIDY in clinical studies. Monitor liver function tests and patients for signs of hepatic injury. Consider discontinuation of PLEGRIDY if hepatic injury occurs

Depression and Suicide

  • Depression, suicidal ideation, and suicide occur more frequently in patients receiving interferon beta than in patients receiving placebo. Advise patients to report immediately any symptom of depression or suicidal ideation. If a patient develops depression or other severe psychiatric symptoms, consider stopping treatment with PLEGRIDY


  • Seizures are associated with the use of interferon beta. The incidence of seizures in clinical studies was less than 1% in patients receiving PLEGRIDY and placebo. Exercise caution when administering PLEGRIDY to patients with a seizure disorder

Anaphylaxis and Other Allergic Reactions

  • Anaphylaxis and other serious allergic reactions are rare complications of treatment with interferon beta. Less than 1% of PLEGRIDY-treated patients experienced a serious allergic reaction such as angioedema or urticaria. Discontinue PLEGRIDY if a serious allergic reaction occurs

Injection Site Reactions

  • Injection site reactions, including injection site necrosis, can occur with the use of subcutaneous interferon beta. The incidence of injection site reactions (e.g., injection site erythema, pain, pruritus, or edema) was 66% in the PLEGRIDY group (3% were severe) and 11% in the placebo group (0% were severe). One patient out of 1468 patients who received PLEGRIDY experienced injection site necrosis. Decisions to discontinue therapy following necrosis at a single injection site should be based on the extent of the necrosis. If therapy is continued, avoid administration of PLEGRIDY near the affected area until it is fully healed. If multiple lesions occur, discontinue PLEGRIDY until healing occurs

Congestive Heart Failure

  • Congestive heart failure, cardiomyopathy, and cardiomyopathy with congestive heart failure occur in patients receiving interferon beta. The incidence of cardiovascular events was 7% in both PLEGRIDY and placebo treatment groups. Monitor patients with significant cardiac disease for worsening of their cardiac condition during initiation and continuation of treatment with PLEGRIDY

Decreased Peripheral Blood Counts

  • Interferon beta can cause decreased peripheral blood counts in all cell lines, including rare instances of pancytopenia and severe thrombocytopenia. Decreases in white blood cell counts below 3.0 x 109/L occurred in 7% of patients receiving PLEGRIDY and in 1% receiving placebo. The incidence of clinically significant decreases in lymphocyte counts (below 0.5 x 109/L), neutrophil counts (below 1.0 x 109/L), and platelet counts (below 100 x 109/L) were all less than 1% and similar in both placebo and PLEGRIDY groups. Monitor patients for infections, bleeding, and symptoms of anemia. Monitor complete blood cell counts, differential white blood cell counts, and platelet counts during treatment with PLEGRIDY. Patients with myelosuppression may require more intensive monitoring of blood cell counts

Thrombotic microangiopathy

  • Cases of thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, have been reported several weeks to years after starting interferon beta products. Discontinue PLEGRIDY if clinical symptoms and laboratory findings consistent with TMA occur, and manage as clinically indicated

Autoimmune disorders

  • Autoimmune disorders of multiple target organs including idiopathic thrombocytopenia, hyper- and hypothyroidism, and autoimmune hepatitis have been reported with interferon beta. The incidence of autoimmune disorders was less than 1% in both PLEGRIDY and placebo treatment groups. If patients develop a new autoimmune disorder, consider stopping PLEGRIDY


  • The most common adverse reactions (incidence greater than 10% and at least 2% more than placebo) associated with PLEGRIDY treatment are injection site erythema, influenza-like illness, pyrexia, headache, myalgia, chills, injection site pain, asthenia, injection site pruritus, and arthralgia


  • There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to PLEGRIDY during pregnancy
  • Encourage patients who become pregnant while taking PLEGRIDY to enroll in the PLEGRIDY pregnancy registry by calling 1-866-810-1462 or visiting https://www.plegridypregnancyregistry.com

Please see full Prescribing Information.


PLEGRIDY® (peginterferon beta-1a) is an interferon beta indicated for the treatment of patients with relapsing forms of multiple sclerosis (MS), to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults.

References: 1.  Kang JS, DeLuca PP, Lee KC. Emerging PEGylated drugs. Expert Opin Emerg Drugs. 2009;14(2):363-380. doi:10.1517/14728210902907847.  2. PLEGRIDY Prescribing Information. Cambridge, MA: Biogen; 2015. 3. 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(7):657-665. doi:10.1016/S1474-4422(14)70068-7. 4. PLEGRIDY Medication Guide. Cambridge, MA: Biogen; 2014.