Plegridy (Peginterferon Beta 1a) for Multiple Sclerosis

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Plegridy (peginterferon beta 1a) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat relapsing forms of multiple sclerosis in adults.

What Members Say

MHT logo These insights are based on 1,184 comments about Plegridy from MyMSTeam members. These are the experiences of a small number of people and are not meant to be medical advice.

Benefits:

Taken once every two weeks
Given at home
Milder or easier to manage side effects over time for some people

Considerations:

Injection-site reactions, such as discoloration, itching, swelling, or bruising
Flu-like symptoms after each dose that can last a day or longer
Mood changes, including depression or anxiety, that may need medical attention

How Plegridy Works and How It’s Taken

Plegridy works by changing immune system activity, but its exact effect in relapsing forms of multiple sclerosis is not fully known. This change may affect how the body’s immune system responds. In multiple sclerosis, the immune system attacks the protective covering around nerves. By changing immune activity, Plegridy may help lower this harmful attack and help control the disease.

Doctors prescribe Plegridy to adults with relapsing forms of multiple sclerosis. The medication is given as an injection under the skin or into a muscle. Treatment starts with lower doses at the first two injections, then continues with a full dose every 14 days. People may be able to give the injections at home after they are trained by a healthcare professional.

Top Advice From Members on Plegridy

These insights are based on 1,184 comments about Plegridy from MyMSTeam members.

Members who use Plegridy often talk about planning ahead for flu-like symptoms, paying close attention to injection site reactions, and staying in touch with their care team about side effects and lab work. Many also mention practical steps that help them stick with treatment, such as timing injections around sleep or weekends, rotating sites, and getting help with cost or delivery issues.

1

Let the medication warm to room temperature before injecting.

“Just used the alcohol swabs and made sure the pen was out of the fridge for about a half hour.”
2

Rotate sites and notice which areas react less.

“My thighs seem to react the worst to the injection — they stay discolored and itchy for anywhere between six to eight weeks afterward. My abdomen injections stay red for two to four weeks, but no itching. However, my arms seem to have no reaction at all other than a couple days of redness.”
3

Keep track of side effects and tell your doctor about lasting or serious reactions.

“My neurologist ran some labs on me last week and it looked like my liver enzymes are elevated, so I have to get more blood work done this week.”

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Plegridy Side Effects

Injection-site redness (skin discoloration where you inject)
Flu-like illness
Fever
Headache
Muscle aches
Chills
Injection-site pain
Asthenia (weakness or low energy)
Injection-site itching
Joint pain

In clinical studies of Plegridy for relapsing forms of multiple sclerosis in adults, the most common side effects occurred in about 11 percent to 62 percent of people.

Serious Side Effects and Warnings

Plegridy can cause serious side effects that require immediate medical attention. These include:

Liver injury (liver inflammation or liver failure; may cause yellowing of the skin or eyes, dark urine, or unusual bleeding)
Depression and suicidal thoughts or behavior (new or worsening mood symptoms, or thoughts of self-harm)
Serious allergic reactions, including anaphylaxis (a life-threatening allergic reaction that can cause swelling, hives, or trouble breathing)
Severe injection-site reactions, including necrosis (skin breakdown), abscess, or cellulitis (a serious skin infection)
Worsening heart problems, including congestive heart failure (the heart may not pump well, causing symptoms like shortness of breath or swelling)
Low blood cell counts (can raise the risk of infections, anemia, or bleeding)
Thrombotic microangiopathy (a rare, serious blood vessel condition that can damage organs)
Pulmonary arterial hypertension (high blood pressure in the lungs that can cause shortness of breath or new or increasing fatigue)
Autoimmune disorders (when the immune system attacks the body, such as thyroid problems or autoimmune hepatitis)
Seizures (episodes of abnormal electrical activity in the brain)

Get medical help right away if you think you are having a serious reaction.

How To Save on Plegridy

Biogen, the manufacturer of Plegridy, offers the Biogen Copay Program. Eligible people with commercial insurance may pay as little as $0. If you have government insurance or no insurance, the website offers information on other ways to save on your prescription.

The Biogen Copay Program also offers help from Biogen Support Coordinators, including support with understanding your insurance coverage and costs, guidance through the prior authorization process, and help exploring financial assistance options. To learn more, visit Biogen financial support information or call 800-456-2255.

What To Know Before Taking Plegridy

Tell your doctor if you have any allergies to peginterferon beta 1a, interferon beta, or any ingredients in Plegridy.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Do not take Plegridy if you have a history of hypersensitivity to natural or recombinant interferon beta or peginterferon, or any other component of Plegridy.

If you are pregnant, planning to become pregnant, or breastfeeding while taking Plegridy, talk with your doctor about the risks and benefits.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Plegridy?
In a 48-week study, people taking Plegridy every 14 days had fewer relapses than those taking placebo (an inactive treatment). The relapse rate was 0.26 compared to 0.40. About 19 percent of people taking Plegridy had a relapse, compared to 29 percent on placebo. Plegridy also lowered the risk of disability getting worse and reduced the number of new or enlarging brain lesions seen on MRI.

How often is Plegridy taken for multiple sclerosis?
After the starting doses, the usual dose is 125 micrograms every 14 days. Treatment begins with lower doses at day 1 and day 15, then reaches the full dose on day 29. Lower starting doses help reduce flu-like symptoms.

Can Plegridy cause flu-like symptoms in people with multiple sclerosis?
Yes. Flu-like symptoms are common. In studies, 47 percent of people taking Plegridy had flu-like illness, compared to 13 percent on placebo. Fever was reported in 45 percent of people. Pain or fever medicines may help with these symptoms.