Man Living with Rare Disease Starts New Chapter Thanks to Targeted Therapy

Jeff was in his late teens when he broke out into a rash of dark, itchy spots that eventually drove him to see a dermatologist. This doctor diagnosed him with systemic mastocytosis (SM), a rare disease that causes the body to overproduce mast cells – a key cell type of the immune system. What Jeff didn’t know was the skin rash was just the beginning of his journey with SM.

It’s been 30 years since Jeff’s diagnosis and since then, his doctors determined he has Advanced SM, a subtype of SM. About 95% of patients with Advanced SM have a KIT D816V mutation – a genetic change that can cause abnormal mast cells to build up in different organs, such as the skin, bone marrow and digestive tract, and may lead to life-threatening effects. While everyone’s experience with Advanced SM is unique, Jeff has had a number of recurring and unpredictable symptoms.

“I had a skin rash known as urticaria pigmentosa all over my body, which would sometimes clump together and look like large bruises or lesions,” said Jeff. “On top of being in physical pain due to the disease, my skin condition caused me to be self-conscious in public.”

He eventually ended his career in construction. He had a swollen spleen, and swelling in his legs made it a “project” to walk up a flight of stairs.

“People with Advanced SM often have limited ability to perform daily activities, because the disease can cause a range of serious, unpredictable symptoms,” said Lauren Denton, Executive Director of The Mast Cell Disease Society.

At one point, Jeff’s disease caused severe anemia and he was hospitalized for multiple weeks to receive blood transfusions. Although Jeff recovered, years later he faced significant weight loss of about 25% of his body weight and critical anemia recurred, requiring transfusions once again.

Jeff visited his local healthcare team, who were unable to help manage the disease’s complications. After trying a form of chemotherapy, he had been told that there were no other options to manage his disease.

“For patients with Advanced SM, additional therapeutic options are needed to help reduce the disease burden and its impact on the body’s organs. It’s also important for these patients to be educated on how to manage their activities of daily living,” said Valerie Slee, Board Chair of The Mast Cell Disease Society.

Targeting the Primary Cause of Advanced Systemic Mastocytosis

Before losing hope, Jeff connected with a family friend who recommended he visit a medical specialist who was treating patients with Advanced SM.

In January 2018, this doctor enrolled Jeff in a clinical trial for avapritinib (now known as AYVAKIT®). The treatment was designed to help slow the growth of mast cells and target the underlying KIT D816V mutation that drives about 95% of Advanced SM cases.

AYVAKIT is a prescription medicine approved by the FDA in June 2021 to treat adults with Advanced SM, including aggressive SM, SM with an associated hematological neoplasm, and mast cell leukemia. AYVAKIT is not recommended for the treatment of Advanced SM in people with low platelet counts (less than 50 x 109/L). It is not known if AYVAKIT is safe and effective in children. AYVAKIT may cause serious side effects including bleeding in the brain, cognitive side effects and embryo-fetal toxicity.

Please see Important Safety Information below.

Impact of Treatment

While individual experiences will vary, Jeff continues to respond to AYVAKIT since he started the treatment. His strength has improved, and the amount of skin lesions has reduced. The swelling in Jeff’s legs has eased, although it can flare up after a long day on his feet. He is participating in activities he loves, including golfing and playing softball, and has taken on part-time jobs, such as coaching youth sports.

Jeff works with his healthcare team to help manage side effects, including nausea and swelling in his hands and face, while he is on treatment. The most common side effects of AYVAKIT in people with Advanced SM include fluid retention or swelling, diarrhea, nausea, tiredness, and changes in certain blood tests. Jeff’s doctors also closely monitor his blood counts for treatment response and other potential side effects.

“My biggest piece of advice for people living with Advanced SM is to seek out disease specialists and ask about treatment options that may be right for them,” said Jeff.


AYVAKIT may cause serious side effects, including:
Bleeding in your brain. Serious bleeding in the brain may happen during treatment with AYVAKIT and may lead to death. Stop taking AYVAKIT and tell your healthcare provider right away if you develop any symptoms such as severe headache, vomiting, drowsiness, dizziness, confusion, or severe weakness on one or more side of your body. Your healthcare provider will check your platelet counts before and during treatment with AYVAKIT.

Cognitive effects. Cognitive side effects are common with AYVAKIT and can be severe. Tell your healthcare provider if you develop any new or worsening cognitive symptoms including forgetfulness, confusion, getting lost, trouble thinking, drowsiness, trouble staying awake (somnolence), word-finding problems, seeing objects or hearing things that are not there (hallucinations), or a change in mood or behavior.

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

  • have low platelet counts
  • have bulging or weakening of a blood vessel wall (aneurysm) or history of bleeding in your brain
  • have a history of stroke within the last year
  • are pregnant or plan to become pregnant. AYVAKIT can cause harm to your unborn baby
    • Females who are able to become pregnant: your healthcare provider should do a pregnancy test before you start AYVAKIT. You should use effective birth control (contraception) during treatment with AYVAKIT and for 6 weeks after the final dose of AYVAKIT. Talk to your healthcare provider about birth control methods that may be right for you. Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with AYVAKIT.
    • Males with female partners who are able to become pregnant should use effective birth control (contraception) during treatment and for 6 weeks after the final dose of AYVAKIT.
  • are breastfeeding or plan to breastfeed. It is not known if AYVAKIT passes into your breast milk. Do not breastfeed during treatment with AYVAKIT and for at least 2 weeks after the final dose of AYVAKIT. 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 and over-the-counter medicines, vitamins, and herbal supplements. AYVAKIT may affect the way other medicines work, and certain other medicines may affect how AYVAKIT works. Talk to your healthcare provider prior to starting a new medicine.

Do not drive or operate hazardous machinery if you have confusion or trouble thinking during treatment with AYVAKIT.

The most common side effects of AYVAKIT in people with AdvSM include fluid retention or swelling, diarrhea, nausea, tiredness, and changes in certain blood tests.

Your healthcare provider may change your dose, temporarily stop, or permanently stop treatment with AYVAKIT if you develop certain side effects. AYVAKIT may cause fertility problems in females and may decrease sperm production in males, which may affect your ability to have a child. Talk to your healthcare provider if this is a concern for you. These are not all of the possible side effects of AYVAKIT. Call your doctor for medical advice about side effects.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.

Please see the full Prescribing Information and Patient Information for AYVAKIT at

This content was developed by Blueprint Medicines Corporation, the manufacturer of AYVAKIT.

Blueprint Medicines, AYVAKIT and associated logos are trademarks of Blueprint Medicines Corporation.

01/2022 USBP-CORAVAASM-21.003.1

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