Plegridy™ Approved for Relapsing Forms of MS

November 3, 2014 update: Biogen Idec announced today that Plegridy is now available by prescription at Specialty Pharmacies. For more information, please visit Biogen’s support services at MS ActiveSource at or call (800) 456-2255.

August 21, 2014 update:
Please note that although Plegridy has been approved by the FDA, the medication will not be available through prescription at pharmacies until the coming months.

On August 15, 2014, Biogen Idec announced that the United States Food and Drug Administration (FDA) had approved Plegridy™ (peginterferon beta-1a) for the long-term treatment of relapsing forms of multiple sclerosis (MS). Manufactured by Biogen Idec, this new medication is the 11th disease-modifying therapy (DMT) to be approved for MS since the early 1990s. Plegridy is given once every two weeks through a subcutaneous self-injection.

Medication Description and Dosing

Plegridy is a pegylated version of interferon beta-1a. Pegylation is a chemical modification of a molecule (in this case the interferon beta-1a molecule) that extends its half-life, which refers to how long a drug stays active in the body before it is metabolized or eliminated. Given the longer half-life, Plegridy does not need to be taken as often as the presently approved self-injected DMTs for MS, which range from once daily to once weekly. This is the first pegylated drug to be approved for the treatment of MS.

Interferons appear to reduce inflammation by modulating a favorable balance between cells that increase inflammation and cells that decrease inflammation. They also reduce the transport of damaging lymphocytes into the brain. Lymphocytes are immune-system cells produced to fight infection and disease.

This new medication has been studied in two groups – with injections given either every two weeks or every four weeks; the two-week dosing was submitted and selected for approval. Additionally, the 125-mcg dose is administered subcutaneously, which is easier and more comfortable than intramuscular injections, using either the Plegridy Pen (a ready-to-use autoinjector) or a prefilled syringe.

According to Biogen Idec, patients should start Plegridy at a reduced dose of 63 micrograms on day one. Two weeks later, on day 15, this second dose is increased to 94 micrograms. The full dose of 125 micrograms is reached on day 29, when the third dose is taken.

Study Results and Side Effects

Plegridy was submitted to the FDA based on the results from the first year of the two-year ADVANCE study. This Phase III clinical trial is an international multi-center study, which is placebo-controlled and double-blinded (so neither the patients nor the treating professionals know who is getting the active treatment). During the first year of this two-year study, the 1,512 participants with relapsing-remitting MS (RRMS) were randomized to receive either the active drug or the placebo, given either once every two weeks or once every four weeks. After the first year of the study, those given a placebo were switched to the active drug.

According to MSAA’s 2014 edition of its MS Research Update (written by Stephen Krieger, MD and reviewed by MSAA Chief Medical Officer Jack Burks, MD), “Plegridy dosed every two weeks significantly reduced MS disease activity versus placebo. Relapses [the annual relapse rates] were reduced by 36 percent, and new brain lesions by 67 percent, compared to placebo at one year. Disability outcomes were also positive in this one-year trial. In total, the proportion of disease activity-free patients over one year was significantly higher in the two treatment groups compared to placebo.”

According to Biogen Idec’s press release issued on August 15th, Plegridy reduced the risk of 12-week confirmed disability progression, as measured by the Expanded Disability Status Scale (EDSS), by 38 percent compared to placebo. In addition to reducing the new or newly enlarging T2-hyperintense lesions by 67 percent (as noted in the previous paragraph), Plegridy also reduced the number of new gadolinium-enhancing lesions by 86 percent compared to placebo.

MSAA’s MS Research Update also states, “The overall incidence of serious adverse events (SAE) and adverse events (AE) was similar among the Plegridy and placebo groups. The most common serious adverse event was infection, which was balanced across all treatment groups (less than or equal to 1 percent per group). The most commonly reported adverse events with Plegridy treatment were redness at the injection site and influenza-like illness. Flu-like illness was reported in 47 percent of both treatment groups compared to 13 percent in the placebo group. These safety data are consistent with the established safety profile of interferon beta-1a therapies for MS.”

According to Biogen Idec’s press release, in addition to “injection-site reaction and flu-like illness” (noted above), more specific common adverse reactions included fever, headache, muscle pain, chills, injection-site pain, weakness, injection-site itching, and joint pain. The pharmaceutical company also notes that the two-year safety data from the ADVANCE study were consistent with safety results observed in year one.

MSAA’s MS Research Update further explains, “After the first year, study participants who were taking the placebo were re-randomized to one of the two treatment groups (taking the active drug either once every two weeks or once every four weeks), and will continue on their new treatment for the remainder of the second year in the study. Once the study is completed, participants will be given the option to enroll in the ATTAIN open-label (no longer blinded) extensions study. Participants will be followed for up to four years in this second study.”

Potential Adverse Events and Safety Information

As specified in Biogen Idec’s press release, rare adverse events that could occur with Plegridy include: liver and cardiac problems, depression, suicidal ideation, seizures, allergic reactions, complications of injection-site reactions, blood-count issues, and autoimmune disorders. The makers of Plegridy provide a listing of safety information, stating that before starting Plegridy, patients should discuss:

  • any present or past mental illnesses
  • liver, blood, heart, seizure, thyroid, or autoimmune problems
  • present medications, vitamins, and herbal supplements
  • if pregnant or planning to become pregnant (not known if Plegridy could harm an unborn baby)
  • if breastfeeding or planning to breastfeed (not known if Plegridy passes into breast milk)

For More Information

To learn more about Plegridy, please visit their website at Biogen Idec also provides a variety of support services for patients and caregivers through MS ActiveSource®. MS ActiveSource is available via phone (Monday-Friday 8:30 am to 8:00 pm ET) at (800) 456-2255 or via web at
Detailed information about MS and its treatments is available on MSAA’s website at Individuals may also call MSAA at (800) 532-7667 for more information. Questions to MSAA’s Client Services Department may be emailed to 

In Closing

MSAA welcomes the addition of another effective and safe treatment to be approved for the long-term treatment of MS. Having more treatment options is of great benefit to the MS community, enabling doctors and their patients to have more options in selecting the best long-term treatment for each individual.

Written by Susan Wells Courtney, MSAA Senior Writer and Creative Director

Reviewed by Jack Burks, MD, MSAA Chief Medical Officer