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Treatment Name: Avapritinib (Ayvakit®)

Avapritinib (Ayvakit®) is a Treatment Regimen for Advanced Systemic Mastocytosis

How does avapritinib (Ayvakit®) work?

Avapritinib is a Tyrosine Kinase Inhibitor (TKI) that is designed to shut off a mutated protein called “KIT”, specifically KIT D816V, that is known to cause increased production and activity of mast cells.

Avapritinib is also known as study drug name: BLU-285

Goals of avapritinib (Ayvakit®) therapy:

Avapritinib is taken to decrease signs and symptoms of mastocytosis but is not commonly given with the goal of cure.


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How is avapritinib therapy for systemic mastocytosis taken?

  • Usual starting dose: 200 mg oral capsule by mouth once a day on an empty stomach
    • Food increases absorption so it is best to take on an empty stomach to avoid an increase in side effects

  • Dosage adjustments are common. For certain adverse reactions (also known as intolerable side effects), the dose may be reduced by your doctor to:
    • 100 mg by mouth once a day for the first occurence
    • 50 mg by mouth once a day for the second occurence
    • 25 mg by mouth once a day for the third occurence
      • Discontinue avapritinib therapy if you are unable to tolerate 25 mg by mouth once a day

  • Do not make up for a missed dose if you are within 8 hours of your next scheduled dose

  • Do not repeat a dose if vomiting occurs. Plan to resume therapy with the next scheduled dose and call your doctor for further instructions

Note: Individual doses may vary based upon your Doctor's recommendation, or drug availability.

Avapritinib is usually taken at home and is continued until the drug no longer works or until unacceptable side effects occur.

Side Effects

What are the most common side effects from avapritinib (Ayvakit®) for systemic mastocytosis?

In clinical studies, the most commonly reported side effects of avapritinib are shown here:

  • Swelling in face, arms, or legs (79%)
  • Low platelets [Thrombocytopenia] (64%)
  • Low red blood cells [Anemia] (55%)
  • Low white blood cells [Neutropenia] (54%)
  • Diarrhea (28%)
  • Nausea (24%)
  • Fatigue and weakness (23%)
  • Vomiting (18%)
  • Headache (15%)
  • Stomach pain (14%)
  • Confusion or memory loss (14%)
  • Changes in taste (13%)
  • Dizziness (13%)
  • Constipation (11%)
  • Bloody nose (11%)
  • Joint pain (10%)
  • Trouble breathing (9%)
  • Watery eyes (9%)
  • Hair loss (9%)
  • Decreased appetite (8%)
  • Itching (8%)
  • Skin rash (8%)
  • Sinus infection (6%)
  • Urinary tract infection [UTI] (6%)
  • Pain in arms or legs (6%)
  • Fluid in belly (5%)
  • Flushing (4%)
  • High blood pressure (4%)
  • Hot flash (3%)
  • Cough (3%)
  • Heart failure (2%)
  • Bleeding in intestines (1%)
  • Gallstones (1%)

On average, 10-15% of patients discontinue treatment due to unacceptable side effects

Importantly, not all people who experience a side effect from avapritinib (Ayvakit®) will experience it in the same way. It may be mild in some or severe in others, depending upon the individual. Everybody is different. Additionally, side effects may vary over time. For some, side effects may be a reason to delay or switch treatment, reduce the dose, or avoid treatment with a certain medication altogether.

Side effects may be treatable when they occur or preventable by taking certain medications before they happen. When medications are taken to prevent a problem, this is known as prophylaxis, or "prophy" for short.

After starting treatment with avapritinib (Ayvakit®), be sure to come back and watch all of the side effect videos shown below. Each of these videos contain valuable information about side effect management that will hopefully help you to both feel better and stay out of the hospital.

Watch videos on common avapritinib (Ayvakit®) therapy side effects below

Side effect videos Side Effect Videos
AnemiaAnemiaDiarrheaDiarrheaNausea and VomitingNausea and VomitingFatigue Fatigue PainPainConstipationConstipationBleedingBleedingHair LossHair Loss


How often is monitoring with avapritinib (Ayvakit®) needed?

Labs (blood tests) may be checked before treatment, every 2 weeks for at least 8 weeks, then at the discretion of your doctor depending on your platelet counts. Labs often include: Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), plus any others your doctor may order.

How often is imaging with avapritinib (Ayvakit®) needed?

Imaging typically is not needed but may be checked if there are concerns for certain side effects. Imaging may include: X-rays, magnetic resonance imaging (MRI), or computerized tomography (CT) scans.

How might blood test results/imaging affect avapritinib (Ayvakit®) treatment?

Depending upon the results, your doctor may advise to continue avapritinib as planned, reduce the dose, delay treatment until the side effect goes away, or switch to an alternative therapy.

Questions to Ask Your...

A better understanding of your treatments will allow you to ask more questions of your healthcare team. We then hope that with the answers, you will get better results and have greater satisfaction with your care. Because we know it's not always easy to know what questions to ask, we've tried to make it easy for you!

Choose any healthcare provider below to see common questions that you may want to ask of this person. Then, either print each list to bring to your clinic visits, or copy the questions and send them as a message to your healthcare team through your electronic medical record.

ChemoExperts Tips

What are the most important things to know about avapritinib (Ayvakit®) while receiving therapy?

  • Avapritinib has been associated with memory impairment, confusion, and difficulty speaking. If any of these side effects occur, your doctor may recommend holding avapritinib therapy until the side effect goes away, or recommend a dosage reduction in avapritinib, or both
  • Although rare, bleeding in the brain can occur while taking avapritinib. This risk is higher if your platelets tend to be low. Alert your doctor immediately if you experience severe headaches, changes in vision, nausea/vomiting, dizziness, confusion, or extreme weakness as these may be a sign of a brain bleed
  • Avapritinib may affect fertility and sperm count. Talk to your doctor about the risk of infertility and steps that can be taken if you plan on having children in the future
  • A pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately
  • Clinical trials may exist for systemic mastocytosis. Ask your doctor if any studies are currently enrolling in your area. If not, go to clinicaltrials.gov to search for other centers offering study medications

Patient Assistance & Co-payment Coverage

Patients under the age of 65 years, or those with private insurance plans:
If you have insurance and are looking for patient assistance or copay assistance for Avapritinib (Ayvakit®), we have provided links that may help.

Visit our Patient Assistance page and click the links to various patient assistance programs for help paying for Avapritinib (Ayvakit®). Depending upon your income, they may be able to help cover the cost of:

  • Avapritinib

For Branded medications (may be available for generic medications too), check with the manufacturer to determine if a co-pay card is offered and if it could reduce your monthly copay.

  • If you are uninsured, check with the manufacturer to determine if you are eligible to receive medication at no cost.

Medicare and Medicaid patients (Patients 65 years or older):
The clinic providing treatment will likely pre-authorize medications and immune therapies such as Avapritinib (Ayvakit®) and are the best source to help you understand drug cost.

  • Ask to speak with a patient assistance technician or financial counselor at the clinic or hospital administering this therapy.

Emotional Wellness

What is Emotional Wellness?
Emotional wellness is having a positive outlook balanced with a realistic understanding of current life events. This requires both an awareness and acceptance of your emotions. It is with this knowledge that you can develop a plan to take the necessary actions to positively impact your life.

Emotional wellness uses an ongoing process to continually reflect on the stressors of life in a constructive manner to move forward and create happiness.

Because emotional wellness is deeply connected with physical, social, and spiritual wellness, pursuing it often becomes particularly difficult in times of major illness. Despite this difficulty, working toward emotional wellness has been connected to improved treatment outcomes and a higher likelihood of achieving goals of therapy.

Learn more about pursuing emotional wellness while receiving treatment with Avapritinib (Ayvakit®)

Individual Drug Label Information

Avapritinib (Ayvakit®)

  • Is an oral capsule available in 25 mg, 50 mg, 100 mg, 200 mg, and 300 mg
  • Is usually taken on an empty stomach, at least 1 hour before or 2 hours after a meal, at the same time each day
  • Food increases absorption so it is best to take on an empty stomach to avoid an increase in side effects
  • If you miss a dose, take the missed dose if it will be 8 hours or more before your next scheduled dose. If it is 8 hours or less until your next scheduled dose, skip the missed dose and take your next dose at the regularly scheduled time. DO NOT double your dose to make up for the missed dose
  • Store at 68°F to 77°F (20°C to 25°C)
  • Dosage adjustments may be required for mental status changes, low platelets, or certain drug interactions
  • May interact with certain antifungal and seizure medications. Ask your doctor or pharmacist to review your medications for any possible interactions
  • May interact with grapefruit and grapefruit juice, pomegranate, star fruit, or Seville oranges (in marmalade) causing increased blood levels of avapritinib. This could increase your risk of experiencing side effects. Avoid eating or drinking these foods during treatment 
  • Avoid therapy with St. John’s Wort, carbamazepine, phenytoin, or enzalutamide as they will decrease blood levels of avapritinib. This could decrease the effectiveness
  • Can cause fetal harm when administered to pregnant women. Males and females of reproductive potential should use effective contraception during treatment and for 6 weeks after the final dose
  • Do not breastfeed during treatment and for 2 weeks following the final dose 
General side effects from avapritinib
  • Swelling in face, arms, or legs 
  • Low platelets, red blood cells, and white blood cells
  • Diarrhea or constipation 
  • Nausea/vomiting
  • Fatigue and weakness
  • Headache
  • Stomach pain
  • Confusion or memory loss
  • Changes in taste
  • Dizziness
  • Bloody nose
  • Joint pain
  • Click on the avapritinib (Ayvakit®) package insert below for reported side effects, possible drug interactions, and other avapritinib prescribing information​

Side Effect Videos
Nausea and VomitingNausea and VomitingDiarrheaDiarrheaHair LossHair LossFatigue Fatigue BleedingBleedingConstipationConstipationPainPainAnemiaAnemia

See DailyMed package insert.

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1. Ayvakit® (avapritinib) package insert. Cambridge, MA: Blueprint Medicines Corporation; June 2021

Created: August 25, 2021 Updated: August 27, 2021

What is Advanced Systemic Mastocytosis?

What is Advabced Systemic Mastocytosis?
A disease of the mast cells that can be found in the skin, internal organs (liver, spleen, GI tract, lymph nodes), and bone marrow. Mast cells can release various chemicals into the body that can produce symptoms of a serious allergic reaction. When these substances cause organ damage, these types of symptoms are known as “C findings,” and include low blood cell counts such as anemia (low red blood cells) or thrombocytopenia (low platelets), liver problems, weight loss, swelling in abdomen, and bone lesions.

Systemic Mastocytosis is a very rare condition that is most commonly caused by a mutation in a protein called “KIT” that causes mast cells to grow and divide. There are various subtypes of mastocytosis, which can vary at diagnosis and throughout treatment.

NOTE: Treatment Options listed below are not all-inclusive. Other treatments may be available. ChemoExperts provides drug information and does not recommend any one treatment over another. Only your Doctor can choose which therapy is appropriate for you.

What does Cure mean?

The word “cure” means there are no cancer cells left in the body and cancer will never come back. Depending on the cancer type and stage, this may be the true goal of therapy. However, it is very difficult to prove all cancer cells are gone. Even though images, like X-rays and MRI’s, and blood tests may not show any signs of cancer, there can be a small amount of cancer cells still left in the body. Because of this, the word “remission” is used more often. This means there are no signs or symptoms of cancer. Patients in remission are followed closely for any signs of cancer returning. Sometimes, more chemotherapy may be given while in remission to prevent the cancer from coming back.

Doctors usually do not consider a patient “cured” until the chance of cancer returning is extremely low. If cancer does return, it usually happens within 5 years of having a remission. Because of this, doctors do not consider a patient cured unless the cancer has not come back within 5 years of remission. The five-year cutoff does not apply to all cancers.

What is a CBC?

A Complete Blood Count (CBC) is a frequently ordered blood test that tells clinicians the status of your: 1) White blood cell count, 2) Hemoglobin, and 3) Platelet count at the time the test was taken.

Common uses:
1) White blood cell count (WBC): is used to determine infection risk, or response to chemotherapy. Certain chemotherapy agents may harm our good infection-fighting cells. Sometimes chemotherapy may need to be delayed to allow these cells to recover.

2) Hemoglobin: is used to determine if someone is anemic. Anytime the hemoglobin is below 12 g/dL, the person is said to be anemic. Red blood cell transfusions, and sometimes iron can be given to restore the hemoglobin level, but anemia treatment should always aim at treating the underlying cause or condition.

3) Platelet count: is used to determine if the risk of bleeding is increased or if a platelet transfusion is required to prevent bleeding. Certain medications that increase bleeding risk, such as: aspirin, certain chemotherapy agents, and blood thinners, may need to be stopped temporarily until the platelet count is within a safe range.

What is a CMP?

A Comprehensive Metabolic Panel (CMP) is a frequently ordered blood test that tells clinicians the status of your: 1) Electrolytes & Acid/Base status2) Kidney function, 3) Liver function, 4) Blood sugar, and 5) Calcium at the time the test was taken. It is commonly used to monitor liver and kidney function when beginning new medications such as chemotherapy. A total of 14 tests are run simultaneously and are shown below.

Electrolytes & Acid/Base status:
1) Sodium, 2) Potassium, 3) Carbon dioxide, 4) Chloride

Kidney Function:
5) BUN (blood urea nitrogen), 6) Serum creatinine (Scr)

Liver Function:
7) AST, 8) ALT, 9) Total bilirubin, 10) Alk Phos, 11) Albumin, 12) Total protein

Blood sugar:
13) Serum glucose

14) Serum calcium