IMPORTANT SAFETY INFORMATION

Reference: 1. Referenced with permission from the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®) for Myeloproliferative Neoplasms V.1.2025. © National Comprehensive Cancer Network, Inc. 2025. All rights reserved. Accessed February 25, 2025. To view the most recent and complete version of the guidelines, go online to NCCN.org. NCCN makes no warranties of any kind whatsoever regarding their content, use or application and disclaims any responsibility for their application or use in any way.

Read this Important Safety Information carefully. It explains the serious risks of BESREMi and how to take it safely. Talk to your healthcare provider if you have any questions.

What is the most important information I should know about BESREMi?

BESREMi can cause serious side effects, including conditions that may cause death or may worsen certain serious diseases you may already have. If symptoms get worse, or become severe and continue, your healthcare provider may tell you to stop taking BESREMi permanently. These symptoms may go away in some people after they stop taking BESREMi.

Mental health problems, including suicide

BESREMi may cause mood or behavior problems that can get worse during treatment or after your last dose, including:

• Irritability (getting upset easily)
• Restlessness and agitation
• Confusion
• Depression (feeling low, hopeless, or bad about yourself)
• Unusually grand ideas
• Acting aggressive or impulsively
• Thoughts of hurting yourself or others, or thoughts of suicide

If you develop any of these symptoms, call your healthcare provider immediately.

New or worsening autoimmune problems

BESREMi may cause your immune system to attack healthy cells, leading to conditions such as thyroid disease, increased blood sugar (hyperglycemia), or type 1 diabetes. Call your healthcare provider if you experience:

• Extreme tiredness
• Frequent urination
• Excessive thirst

Heart problems

BESREMi may cause heart problems, including:

• Cardiomyopathy (heart muscle disease)
• Heart attack
• Irregular heartbeat (atrial fibrillation)
• Decreased blood flow to the heart

You should not take BESREMi if you have:

• Uncontrolled high blood pressure
• Congestive heart failure
• A serious abnormal heart rhythm
• Narrowing of the arteries to your heart
• Certain types of chest pain (angina)
• A recent stroke or heart attack

Who should not take BESREMi?

Do not take BESREMi if you:

• Have or had severe mental health problems, especially depression, suicidal thoughts, or attempted suicide
• Have or had a serious or untreated autoimmune disease
• Are allergic to interferon or any ingredient in BESREMi (symptoms may include itching, swelling, trouble breathing, dizziness, or chest pain)
• Have certain types of liver disease
• Have had a transplant and take immune-suppressing medication

Before using BESREMi, tell your healthcare provider about all of your medical conditions, including if you have any of the following:

Do not take BESREMi if you:

• A mental illness
• Type 1 diabetes
• Heart or bleeding problems
• Problems with your immune system
• Hepatitis B or HIV infection
• Kidney or liver problems
• Are pregnant or planning to become pregnant
  • BESREMi may harm your unborn baby. Use effective birth control during treatment and for at least 8 weeks after your last dose
  • BESREMi may affect your menstrual cycle and could stop your periods
  • Do not breastfeed while taking BESREMi

What are the possible side effects of BESREMi? Serious side effects include:

• Low blood cell counts: taking BESREMi can lead to infections, anemia, or bleeding problems. Call your healthcare provider right away if you develop weakness and tiredness, bruising easily, nose bleeds often, fever, chills, burning and painful urination, urinating often, or coughing up yellow or pink mucus (phlegm)
• Serious allergic reactions: Get medical help right away if you get any of the following symptoms: skin rash or hives; itching; swelling of the face, eyes, lips, tongue, or throat; trouble breathing; chest pain; or feeling faint
• Eye problems: BESREMi can cause severe eye problems with your retinas that can lead to vision loss or blindness. You should have an eye exam before and during treatment with BESREMi if you have diabetes or high blood pressure and also have retinal problems
• Liver problems: BESREMi can cause increases in liver enzymes and liver damage. Your healthcare provider should do blood tests to monitor your liver enzymes and liver function before you start and during treatment with BESREMi
• Kidney problems: Your healthcare provider will do blood tests to check your kidney function before starting and during treatment with BESREMi. Tell your healthcare provider right away if you develop any symptoms of a kidney problem, including: changes in the amount or color of your urine, swelling in your ankles, blood in your urine, or loss of appetite
• Tooth and gum problems: BESREMi can cause tooth loss and/or dry mouth. It is important for you to brush your teeth well, two times each day and have regular dental examinations during treatment with BESREMi
• Skin reactions: BESREMi may cause reaction such as rash, itching, and hair loss
• Increased triglycerides: You may require blood tests to monitor levels

The most common side effects of BESREMi include:

• Flu-like symptoms, including tiredness, weakness, fever, chills, muscle aches, and joint pain
• Itching
• Sore throat

These are not all of the possible side effects of BESREMi.

Call your doctor for medical advice about side effects. You may report side effects to PharmaEssentia at 1-800-999-2449 or FDA at 1-800-FDA-1088.

Please see full Prescribing Information, including Boxed Warning and Medication Guide for BESREMi.