Educational Resources for KOSELUGO® (selumetinib)

At Children's Tumor Foundation (CTF), our goal is to be the central, trusted resource for the entire NF community-connecting families to the latest research, expert care, and helpful tools at every stage of their journey. As part of that commitment, we also share vetted information from our partners when it may be useful to patients and caregivers.

Below, we're pleased to share educational resources from our partners at Alexion about Koselugo (selumetinib), an FDA-approved treatment option for some children and adults with NF1. While this content was developed by Alexion, we believe the educational materials and support resources may be helpful for families navigating NF1 and plexiform neurofibromas. As always, we encourage families to discuss all treatment decisions with their medical care team.

Educational Resources for KOSELUGO® (selumetinib)

Learn More About Koselugo

INDICATION
Koselugo is a prescription medicine that is used to treat adults and children 1 year of age and older with neurofibromatosis type 1 (NF1) who have plexiform neurofibromas that cause symptoms and cannot be completely removed by surgery.

It is not known if Koselugo is safe and effective in children under 1 year of age.

SELECT IMPORTANT SAFETY INFORMATION for Koselugo

• Serious side effects include: heart problems, eye problems, stomach, intestine, and mouth (gastrointestinal) problems, skin problems, increased level of an enzyme called creatine phosphokinase (CPK) in your blood and muscle problems, embryo-fetal toxicity.
• Most common side effects in children include: vomiting, diarrhea, increased level of an enzyme called creatine phosphokinase (CPK) in your blood, dry skin, redness around the fingernails, nausea, skin bumps that look like acne, fever.
• Most common side effects in adults include: rash, diarrhea, skin bumps that look like acne.

Please see full Important Safety Informationfor Koselugoat the end of this blog post.

Updates and Announcements

Alexion is excited to tell you that Koselugo, the first FDA-approved treatment for children and teens with NF1 plexiform neurofibromas (also called plexiforms) is approved for adults. This milestone is more than a treatment option-it's a sign of progress for the NF1 plexiform community. At Alexion, we remain committed to supporting the NF1 community and empowering individuals and families as they navigate their care journey.

Supporting the NF1 Community

One of our main takeaways from the NF Summit each year is the sense of community and empowerment between NF1 families. We understand that a diagnosis of NF1 can feel overwhelming and leave you with many questions. Koselugo comes with a team and a suite of resources, so you are never alone in your NF1 journey.

Koselugo Comes with a Team

Alexion's Patient Education Managers (PEMs) are on hand to provide free, personalized, one-to-one support for your family throughout your journey with NF1. PEMs can answer all your questions about NF1 and Koselugo or lend an ear if you just need someone to listen. PEMs also regularly bring the NF1 community together by hosting virtual and in-person educational events. Register here for an upcoming event.

You don't have to be taking Koselugo to talk to a PEM or attend Koselugo's free educational events, so don't hesitate, contact a PEM today!

Free Koselugo Resources are Available

• Head over to the Koselugo websiteto download a suite of free educational resources. One of the most popular Koselugo resources is the Starter Kit -a one-stop-shop of information to help adults, caregivers, and families learn all about NF1 plexiform neurofibromas, Koselugo, and the support available.
• Request a Starter Kit
• Make sure to also visit the CTF Resource Center, which hosts a library of information about NF and the research underway.

Here's to CTF's 2026 NF Summit!

It was a privilege to meet so many of you at last year's NF Summit, and we are honored to support families with NF1 at every step of their journey. We already can't wait to see you again at the 2026 NF Summitand catch up with you. In the meantime, we hope the resources will be valuable to you, and we look forward to seeing you at the upcoming Koselugo educational events.

To find out more about Koselugo, visit Koselugo.com.

IMPORTANT SAFETY INFORMATION

What are the possible side effects of Koselugo?

Koselugo may cause serious side effects, including:

• Heart problems. Koselugo can lower the amount of blood pumped by your heart, which can be severe. Your healthcare provider will do tests before and during treatment to check how well your heart is working. Tell your healthcare provider right away if you get any of the following signs or symptoms: persistent coughing or wheezing, shortness of breath, swelling of your ankles and feet, tiredness, increased heart rate.
• Eye problems.Koselugo can cause eye problems that can lead to blindness. Your healthcare provider will check your vision before and during treatment. Tell your healthcare provider right away if you get new or worsening vision changes, including: blurred vision, loss of vision, dark spots in your vision (floaters), other changes to your vision.
• Stomach, intestine, and mouth (gastrointestinal) problems. Koselugo can cause diarrhea, vomiting, nausea, and mouth sores. Diarrhea can be severe with Koselugo. Tell your healthcare provider right away the first time that you get diarrhea during treatment. Your healthcare provider may give you medicine to help control your diarrhea and may tell you to drink more fluids.
• Skin problems. Koselugo can cause severe skin rashes. Tell your healthcare provider if you get any of the following signs of skin problems: rash that covers a large area of your body, flat skin rash, raised bumps on your skin, skin bumps that look like acne, blisters, peeling skin, itchy rash, hair thinning or hair loss (alopecia).
• Increased level of an enzyme called creatine phosphokinase (CPK) in your blood and muscle problems. Koselugo can cause severe muscle problems. Treatment with Koselugo may increase the level of an enzyme in your blood called creatine phosphokinase (CPK), which may be a sign of muscle damage. Increased level of CPK in the blood is common during treatment and can also be severe. Your healthcare provider should do a blood test to check your blood levels of CPK before you start taking Koselugo and during treatment. Tell your healthcare provider right away if you get any of the following signs or symptoms: muscle aches or pain; muscle spasms and weakness; dark, reddish urine.

Your healthcare provider may change your dose, temporarily stop, or permanently ask you to stop taking Koselugo if you have any of these side effects.

Before taking Koselugo, tell your healthcare provider about all your medical conditions, including if you:

• Have heart problems.
• Have eye problems.
• Have liver problems.
• Females who are able to become pregnant:
• Your healthcare provider should check to see if you are pregnant before you begin treatment.
• You should use effective birth control (contraception) during treatment and for 1 week after your last dose.
• Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment.
• Males with female partners who are able to become pregnant:
• You should use effective birth control (contraception) during treatment and for 1 week after your last dose.
• Are breastfeeding or plan to breastfeed. It is not known if Koselugo passes into your breast milk. Do not breastfeed during treatment and for 1 week after your last dose. Talk to your healthcare provider about the best way to feed your baby during this time.

Tell your healthcare provider about all the medicines you take,including prescription, over-the-counter medicines, vitamins, or herbal supplements. Certain medicines may affect the way Koselugo works. Especially tell your healthcare provider if you are taking a supplement containing vitamin E, aspirin, blood thinners, or other medicines to treat blood clots. Koselugo capsules contain vitamin E, which may increase risk of bleeding.

What should I avoid while taking Koselugo?

Avoid St John's wort, grapefruit or grapefruit juice, and Seville oranges during treatment.

Most common side effects in children include: vomiting, diarrhea, increased level of an enzyme called creatine phosphokinase (CPK) in your blood, dry skin, redness around the fingernails, nausea, skin bumps that look like acne, fever.

Most common side effects in adults include: rash, diarrhea, skin bumps that look like acne.

These are not all the possible side effects of Koselugo. Call your healthcare provider for medical advice about side effects. You may report side effects to AstraZeneca at 1-800-236-9933 or at https://us-aereporting.astrazeneca.com or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Please see Patient Information and Instructions for Use in the full Prescribing Informationfor Koselugo (selumetinib).

FDA=Food and Drug Administration; NF=neurofibromatosis.

KOSELUGO is a registered trademark of the AstraZeneca group of companies.
ALEXION is a registered trademark of Alexion Pharmaceuticals, Inc.
© 2026, Alexion Pharmaceuticals, Inc. All rights reserved.
US/KOS-NF1/0949 V2 01/2026