Finding Strength in Support: One Man’s Journey with a Rare Disease

Dennis, 67, was never someone who enjoyed taking it easy. He was an electrician by trade and a dedicated athlete, regularly running marathons and cycling all over his hometown. But everything changed when he started experiencing a range of unpredictable and potentially debilitating symptoms in his early 40s.

"I was constantly fatigued, and I started noticing little red dots all over my body that looked like freckles," Dennis recalls. "I would itch all over. I couldn't stop myself from scratching, even when I'd wake up with blood on my sheets."

Dennis noticed certain smells and fabrics triggered reactions. "If I visited a friend who was burning soy candles in their home, I'd get sick as a dog," he says. "My eyes would start burning and my skin would become very irritated." Dennis remembers walking through the grocery store with his wife, Jennifer, and having allergic reactions because of the overwhelming scent of the laundry detergent aisle.

Although Dennis saw a variety of specialists, he didn't get a diagnosis. When he went into anaphylactic shock from eating a slice of pizza, a food that never gave him trouble before, he knew he needed to take action. He asked his family doctor to refer him to an immunologist, who recommended Dennis get a bone marrow biopsy.

Nine years after he first started experiencing symptoms, Dennis' bone marrow biopsy finally confirmed his diagnosis: a rare disease called indolent systemic mastocytosis (ISM). This chronic condition is characterized by the buildup of abnormal mast cells, which play an important role in immune responses to allergens, infection and injury. As the cells accumulate, they can cause potentially debilitating symptoms such as skin lesions, diarrhea, fatigue, bone pain and life-threatening anaphylaxis. These symptoms are often unpredictable and can be triggered by anything from certain foods to temperature changes to fragrances.

While Dennis was relieved to know the cause of his symptoms, it was hard to accept how his life was changing.

Learning to Advocate Together

After his retirement, Dennis was committed to learning more about his symptoms and ISM. Though Dennis was confident in his ability to navigate difficult situations independently, he knew he would need a strong support system to live with ISM.

Jennifer became the cornerstone of this team. She helped handle many of the tasks he found difficult to do, drove Dennis to his appointments, captured extensive notes during check-ups and recounted Dennis' experiences in detail to his doctors from her point of view.

As a caregiver, Jennifer had unique insight into how Dennis was feeling, even when he forgot symptoms or downplayed their severity. "With my fatigue and brain fog, it can be hard for me to remember every symptom when I'm at the doctor's office. She advocates for me and fills in the gaps. We've been a pretty good team."

Dennis and Jennifer's partnership helped his doctors better understand the impact of Dennis' ISM and adjust their approach to treatment accordingly.

Finding the Right Treatment

Despite confirming his ISM diagnosis and trying several medications to treat his symptoms, Dennis struggled to keep them under control. "My disease was like a rollercoaster," he explains. "Often, before I even got to the breakfast table, my symptoms would start to flare up and disrupt the plans I had for my day."

Dennis knew he needed another treatment that would improve his symptoms. With the support of his wife, Dennis felt empowered to advocate for himself and find an approach that worked for him.

In partnership with his immunologist, Dennis decided to try AYVAKIT^®(avapritinib), the only U.S. Food and Drug Administration (FDA)-approved treatment for adults with ISM. AYVAKIT is not recommended in people with low platelet counts (less than 50 X 10⁹/L). It is a once-daily pill that works by targeting a specific gene mutation, KIT D816V, the source of ISM. AYVAKIT blocks the overproduction of these abnormal mast cells.

AYVAKIT may cause serious side effects such as cognitive effects, skin sensitivity to sunlight (photosensitivity), and effects on pregnancy and fertility. The U.S. Food and Drug Administration approved AYVAKIT based on clinical study results that evaluated AYVAKIT in combination with symptom-directed therapies at six months on overall ISM symptoms: brain fog, dizziness, headache, fatigue, flushing, bone pain, itching, spots on the skin, abdominal pain, diarrhea and nausea.

Please see Important Safety Information below and click here for full Prescribing Information including Patient Information.

After taking AYVAKIT, Dennis has seen significant changes and continues to take it after nearly two years. "I still experience some of my symptoms, but they're more manageable. I have less fatigue and itching and feel more comfortable spending my time on newfound hobbies."

A New Path Forward

Dennis credits his wife's unwavering presence for helping him adapt to his new normal and find new ways to feel fulfilled. "I have a great support system with Jennifer and keep myself busy every day with my new hobbies," Dennis says.

Though he doesn't run or bike anymore, Dennis has found joy in other hobbies. Dennis enjoys building elaborate birdhouses that he gifts to his friends and family or auctions at charity events.

"They take the whole summer to make," Dennis explains. He has always loved the outdoors, and woodworking offers the opportunity for him to connect with nature. Dennis repurposed trimmings from an overgrown tree for his first birdhouse, surprising even himself with his natural ability to blend creativity and technical skill. Since then, the scale and frequency of his craft has grown exponentially. The birdhouses are highly intricate and each include unique details such as carved names and bird-themed weathervanes.

In the winter, Dennis works with leather, crafting detailed belts, phone cases, and saddles and creates custom, handmade jewelry. Dennis credits his hobbies for keeping him grounded, happy and engaged through the ups and downs of his ISM journey.

Dennis' journey hasn't been easy, from years of unanswered questions to the physical and emotional toll of living with ISM. But through it all, Dennis has persevered. The support of Jennifer and his healthcare team has enabled him to seek out better care and discover new support channels and hobbies.

"Even though living with ISM comes with unpredictability, having the support of a care team and a community—combined with finding a treatment that works for you—can help you find a path forward and rediscover things that make you happy."

To learn more about AYVAKIT and connect with others about their experience, visit AYVAKIT.com.

USE AND IMPORTANT SAFETY INFORMATION

WHAT IS AYVAKIT^® (avapritinib)?

AYVAKIT^® (avapritinib) is a prescription medicine used to treat adults with indolent systemic mastocytosis (ISM). AYVAKIT is not recommended in people with low platelet counts (less than 50 X 10⁹ /L). It is not known if AYVAKIT is safe and effective in children.

IMPORTANT SAFETY INFORMATION

AYVAKIT^® (avapritinib) may cause serious side effects, including:

Cognitive effects. Cognitive side effects can happen during treatment 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.

Skin sensitivity to sunlight (photosensitivity). Your skin may be sensitive to the sun or other forms of light (photosensitivity) during treatment with AYVAKIT. Avoid or limit exposure to direct sunlight, sunlamps, and other sources of ultraviolet radiation during treatment and for 1 week after stopping treatment with AYVAKIT. Use sunscreen or wear clothes that cover your skin if you need to be out in the sun.

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

• history of bulging or weakening of a blood vessel wall (aneurysm) or bleeding in your brain
• have a history of stroke within the last year
• have low platelet counts
• have or have had liver problems
• 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. Especially tell your healthcare provider if you take estrogen-containing hormonal birth control or medicines that prevent blood clots.

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 ISM include: swelling around your eyes, dizziness, swelling of your arms and legs, and flushing.

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 males. 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 side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

AYVAKIT is available in a 25 mg tablet.

Please click here to see the full Prescribing Information and Patient Information for AYVAKIT.

To learn more about AYVAKIT, visit AYVAKIT.com.

This promotional content was developed by Blueprint Medicines Corporation, the manufacturer of AYVAKIT. Individual results may vary. Dennis is being compensated by Blueprint Medicines for sharing his story.

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

© 2025 Blueprint Medicines Corporation.

USAVA25.0060.1 | 05/2025