Peginterferon alfa-2b (Sylatron)

How is this drug name pronounced?

Peginterferon alfa-2b: peg-IN-ter-FEER-on AL-fuh-too-bee

Sylatron: SY-luh-tron

What cancer(s) does this drug treat?


Sylatron is approved for:

  • Patients with melanoma that has spread to the lymph nodes, and who have undergone surgery to remove the cancer and the affected lymph nodes. Sylatron is used to prevent melanoma from coming back, and should be started within 84 days after surgery.

Limitations of use:

Age: The safety and efficacy of Sylatron in patients under 18 years of age have not been established.
Exclusions: Sylatron should not be administered to patients who have autoimmune hepatitis or who have severe liver damage.
Patients with impaired kidney function: Patients with impaired kidney function should be treated with a lower dose of Sylatron.
Fertility/Pregnancy/Breastfeeding: Sylatron may transiently impair fertility in women. Sylatron can cause harm to a fetus, and is not recommended for use during pregnancy. Women should use contraception during treatment with Sylatron and for at least 10 days after the final dose of Sylatron. The risks associated with Sylatron during breastfeeding are not known and cannot be ruled out. Due to the potential for adverse reactions in the breastfed child, the benefits of breastfeeding and the mother’s need for treatment should be weighed accordingly before moving forward with treatment Sylatron.
Interaction with other drugs: Sylatron can inhibit the activity of CYP1A2 and CYP2D6 proteins, which break down (metabolize) certain drugs (e.g., desipramine). When Sylatron and drugs that are broken down by CYP1A2 and CYP2D6 are given together, the patient's body may be exposed to a higher concentration of the drug than intended.

What type of immunotherapy is this?

Cytokine therapy

  • Immunomodulator

How does this drug work?

  • Target: Type I interferon receptors (IFNAR1/2)

Sylatron is a protein that is a laboratory-made version of interferon alfa-2b (IFNalpha-2b) – a protein called an interferon that exists in the human body. Interferons are an important part of “cell signaling”, which is when different cells in the body “talk” to one another using chemical signals. Sylatron binds to type I interferon receptors, found on the surface of many different types of cells, including immune cells and cancer cells. The exact mechanism by which Sylatron helps fight melanoma is not known. It is thought to activate one or more parts of the immune system in its fight against cancerous cells, to directly induce death in cancer cells, or to work in both ways.

How is this drug given to the patient?

Half an hour prior to the first injection of Sylatron, and prior to subsequent injections, which are given as needed, patients take acetaminophen to help prevent “flu-like” symptoms (chills, fever, muscle aches, joint pain, headaches, tiredness).

Using a syringe, Sylatron is injected under the skin once a week for up to five years. Patients self-administer Sylatron after being instructed by their healthcare provider. Sylatron should be administered at bedtime. Patients should drink plenty of fluids while being treated with Sylatron.

What are the observed clinical results?

It is important to keep in mind that each patient’s actual outcome is individual and may be different from the results found in the clinical studies. In addition, with immunotherapy, sometimes it takes several months for responses to be observed.


In a clinical trial, 1256 patients with melanoma that had spread to the lymph nodes, and who had undergone surgery to remove the cancer and the affected lymph nodes, were treated with either Sylatron or observed (no treatment). Treatment was started within 84 days after surgery.

For patients treated with Sylatron, the disease did not return for a median of 35 months, compared with 26 months for patients receiving no treatment. There was no difference in survival between the two treatment groups.

What are the side effects?

The most common side effects of Sylatron include fatigue, flu-like symptoms (including fever, headache, tiredness, muscle or joint aches, and chills), nausea, loss of appetite, feeling sad or depressed, redness, swelling, or itching around the injection site, and changes in blood tests that measure how well the liver works.

Sylatron can cause side effects that can become serious or life-threatening, and may lead to death. Some of the serious side effects related to Sylatron include diabetes, mental health problems, and problems with the heart, eyes, thyroid, or liver (including liver failure).

Serious mental health problems

Sylatron can cause serious mental health problems, such as depression, which can lead to suicide. Sylatron can also increase the risk of relapse in patients recovering from drug addiction. Such reactions may occur up to 6 months after the last treatment with Sylatron. Some of the symptoms of serious mental health problems include irritability, depression, aggressive behavior, and thoughts of hurting oneself or others.

Patients should report any symptoms to their healthcare provider, who can then initiate actions to limit or reverse the side effects. For a more complete list of possible side effects, see the full prescribing information.

Additional information


  • Merck


  • FDA

Last updated on April 29, 2021

Understanding Cancer Immunotherapy Research