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Treatment Name: Midostaurin (Rydapt®)

Midostaurin (Rydapt®) is a Chemotherapy Regimen for Systemic Mastocytosis

How does midostaurin (Rydapt®) work?
Midostaurin is designed to shut off a mutated protein called “KIT,” specifically KIT D816V, that causes increased production and activity of mast cells. Although a majority of patients have the KIT mutation (90%), patients who do not have the KIT mutation may still benefit from midostaurin therapy.

Goals of therapy:
Midostaurin is taken to decrease symptoms of mastocytosis such anaphylaxis, skin rash, problems with internal organs such as the liver, spleen or bone marrow, low blood counts, and weight loss. Some patients who require red blood cell or platelet transfusions may become transfusion independent after taking midostaurin.

In patients with systemic mastocytosis, elevated tryptase levels in the blood correlate with disease burden. Therefore, reducing tryptase levels is often a goal of therapy as well.

Midostaurin (Rydapt®) is not commonly given with the goal of cure, but may increase lifespan.


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  • Usual midostaurin starting dose: 100 mg (four 25 mg capsules) by mouth twice daily

Midostaurin (Rydapt®) is usually taken at home. Treatment is continued until the drug no longer works or until unacceptable side effects occur.

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


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Side Effects

In clinical studies, the most commonly reported side effects of midostaurin (Rydapt®) are shown here:

After one year of taking midostaurin, most patients regain lost weight and gain approximately 12 pounds (weight gain or loss may vary).

Roughly 22% of patients taking midostaurin discontinue treatment due to unacceptable side effects.

Side effect videos Side Effect Videos
Nausea and VomitingNausea and VomitingAnemiaAnemiaDiarrheaDiarrheaBleedingBleedingFatigue Fatigue ConstipationConstipationPainPain


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How often is monitoring needed?
Labs (blood tests) may be checked weekly for four weeks, then every other week for 8 weeks, then monthly thereafter. Labs often include: Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), serum tryptase, serum bilirubin, serum alkaline phosphatase, plus any others your doctor may order.

How often is imaging needed?
Imaging may be checked before treatment then every 3 to 6 months thereafter. Imaging may include: X-rays, magnetic resonance imaging (MRI), or computerized tomography (CT) scans. An ECG, or “EKG” may be performed if you are taking other medicines that could lead to a change in heart rhythm. Spleen size may be measured by your doctor by gently pressing on the left side of your abdomen and feeling just below your rib cage. On occasion, spleen size is measured using MRI.

How might blood test results/imaging affect treatment?
Depending upon the results, your doctor may advise to continue midostaurin as planned, reduce the dose of future treatments, delay the next dose until the side effect goes away, or switch to an alternative therapy.

Midostaurin dose reductions due to side effects were common in the clinical trial for mastocytosis, occurring in 56% of patients. Roughly one in three (32%) of patients were able to increase the dose back to the starting dose after the side effect went away.


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ChemoExperts Tips

  • Midostaurin may cause nausea and vomiting. An anti-nausea medication such as ondansetron (Zofran®), prochlorperazine (Compazine®), or promethazine (Phenergan®) can be taken 30 to 60 minutes before each dose of midostaurin to help minimize nausea
  • Patients should seek medical attention if they develop a new cough, chest pain or discomfort, or shortness of breath as lung problems could occur while taking midostaurin
  • Electrocardiograms (ECG, or “EKG”) are checked during therapy to monitor your heart QTc interval because midostaurin can affect this. Many other medications can also affect the QTc interval so check with your doctor or pharmacist if you are taking any of these medications
  • A pharmacist should ALWAYS review your medication list to ensure that drug interactions are prevented or managed appropriately
  • Clinical trials may exist for mastocytosis. Ask your doctor if any studies are currently enrolling in your area. If not, go to 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 Midostaurin (Rydapt®), 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 Midostaurin (Rydapt®). Depending upon your income, they may be able to help cover the cost of:

  • Midostaurin

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 Midostaurin (Rydapt®) 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 Midostaurin (Rydapt®)

Individual Drug Label Information

Midostaurin (Rydapt®)

  • Is an oral 25 mg capsule
  • May cause serious lung injury. Notify your doctor if you experience any new shortness of breath, wheezing, or cough
  • Is usually taken with food, swallowed whole, and should not be opened or crushed
  • If you miss a dose, skip the missed dose and take then next dose as scheduled. DO NOT take two doses to make up for the missed dose
  • Should be stored at 68 - 77°F (room temperature). Do not remove capsules from package until immediately prior to taking your dose
  • Dosage adjustments may be required for low blood counts (red blood cells, white blood cells or platelets) or other serious side effects. Doses are typically not adjusted for low blood counts when being used to treat leukemia
  • 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 midostaurin. This could increase your risk of experiencing side effects. Avoid eating or drinking these foods during treatment 
  • Avoid therapy with St. Johns Wort, carbamazepine, phenytoin, or enzalutamide as they will decrease blood levels of midostaurin. This could decrease the effectiveness
  • May cause fetal harm. Males and females of reproductive potential should use contraception during treatment and for 4 months after the last dose
General side effects from midostaurin (Rydapt®)
  • Neutropenic fever
  • Low red blood cells, white blood cells, or platelets
  • Mouth sores (mucositis)
  • Bruising or bleeding
  • High blood sugar
  • Infection
  • Abdominal pain
  • Constipation or diarrhea
  • Nausea and vomiting
  • Headache
  • Abnormal heart rhythm
  • Muscle and joint pain
  • Excessive sweating
  • Infections 
  • Kidney injury
  • Trouble sleeping
  • Fluid collection around lungs or heart
  • Click on the midostaurin (Rydapt®) package insert below for reported side effects, possible drug interactions, and other midostaurin prescribing information

Side Effect Videos
Nausea and VomitingNausea and VomitingDiarrheaDiarrheaBleedingBleedingConstipationConstipationPainPainAnemiaAnemiaNeutropenic FeverNeutropenic FeverBlood ClotsBlood Clots

See DailyMed package insert.

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Gotlib J, Kluin-Nelemans HC, George TI, et al. Efficacy and Safety of Midostaurin in Advanced Systemic Mastocytosis. N Engl J Med. 2016;374:2530-2541.

Created: May 1, 2017 Updated: October 17, 2018

What is Systemic Mastocytosis?

What is 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.

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

What is the QTc interval?

The time it takes your heart to make one beat can be measured using an electrocardiogram (ECG, or EKG) and is reported as the QTc interval. Midostaurin is generally safe to give when the QTc interval for men is less than 450 milliseconds per beat, and for women, less than 460 milliseconds per beat.

The QTc interval is prolonged if the heart takes too long to make the next beat, and could lead to a dangerous heartbeat known as an arrhythmia.

Certain medications, in addition to midostaurin, may prolong the QTc interval. The list includes: ondansetron (Zofran®), Levofloxacin or ciprofloxacin antibiotics. Make sure your pharmacist checks all new medications to make sure they do not prolong the QTc interval.