Medications to Treat Mast Cell Diseases

There is great heterogeneity in the presentation of mastocytosis and mast cell activation syndromes (MCAS). Some patients present with no or very few symptoms, while others are almost completely debilitated by chronic symptoms that require a multitude of medications to control. Treatment plans, including the use of medication, will differ from person to person and patients should discuss all treatment options with their healthcare provider. Below are some of the medications that could be part of a treatment plan for a patient with a mast cell disease.

ALL PATIENTS:

Epinephrine: All patients with a mast cell disease should always carry two doses of epinephrine for emergency use, even if they have never experienced anaphylaxis. Epinephrine can be given by auto-injector or as an intranasal spray. Both the patient and their family members or caregivers should be trained on how to recognize anaphylaxis and correctly administer epinephrine.

Please visit the American Academy of Allergy, Asthma and Immunology (AAAAI) website for more information on anaphylaxis. The AAAAI resources on anaphylaxis also include an anaphylaxis action plan and wallet card.

Basic Medications for Symptomatic Patients with Mast Cell Diseases^1-4

The medications below may be recommended by a physician to treat symptoms of mast cell activation for patients with any mast cell disease. These medications are meant to improve symptoms and provide supportive care and not to modify the mast cell disease itself.

• H1 antihistamines: help with itching, abdominal pain, flushing, headaches, brain fog
• H2 antihistamines: help with gastrointestinal symptoms and overall mast cell stability (all mast cell activation symptoms)
• Mast cell stabilizers: help with stomach and intestinal symptoms and brain fog
• Leukotriene inhibitors: help with respiratory symptoms and overall mast cell stability (all mast cell activation symptoms)
• Aspirin therapy (under direct supervision of a physician): if tolerated and if prostaglandins are elevated, helps with flushing, brain fog and bone pain

Note: The H1 and H2 antihistamines are necessary to stabilize receptors on the mast cell. Therefore, if additional medication is required for control of gastroesophageal reflux (GERD), a proton pump inhibitor may be added to this protocol, but it cannot replace the H2 antihistamine.

Please see Tables 1-6 below for lists of some specific drugs in these different categories. We also have a downloadable guide to supportive care medications for patients with mast cell diseases.

DOWNLOAD THE PDF

Targeted Therapies for Patients with Systemic Mastocytosis

There are now approved treatments for both indolent and advanced forms of systemic mastocytosis and there are still other treatments being studied in clinical trial. One of the main types of treatment is called a tyrosine kinase inhibitor (TKI), which targets a protein called KIT that affects how mast cells grow.

Avapritinib is a TKI that is approved to treat both indolent and advanced forms of systemic mastocytosis. Midostaurin is another TKI that is approved for advanced systemic mastocytosis. These treatments can help reduce the number of mast cells in the body and improve symptoms.

Other standard treatments for advanced forms include interferon and a chemotherapy drug called cladribine. These are sometimes combined with medicines that help control symptoms caused by mast cells.

People who have systemic mastocytosis along with another blood cancer (called SM-AHN) are usually treated based on the other disease, which is often more serious. Rare types like mast cell leukemia or mast cell sarcoma need stronger combination chemotherapy.

Please see Table 7-9 below for a list of some specific drugs for the variants of systemic mastocytosis. We also have a downloadable guide to targeted therapies for systemic mastocytosis.

DOWNLOAD THE PDF

Table 1. Some First Generation H1 Antihistamines

Table 2. Some Second Generation H1 Antihistamines (may tend to cause less drowsiness)

*Zaditor® is only available in the US as eye drops; Zaditen® is available by prescription, but it must be obtained from a compounding pharmacy or from abroad.

Table 3. Some H2 Antihistamines

Table 4. Some Leukotriene Inhibitors

Table 5. Mast Cell Stabilizers

* Zaditor® is only available in the US as eye drops; Zaditen® is available by prescription, but it must be obtained from a compounding pharmacy or from abroad.

Table 6. Proton Pump Inhibitors to Help with GERD (Gastroesophageal Reflux)

Table 7. Targeted Therapies/ Small Molecule Inhibitors may be prescribed for Selected Patients with Smoldering and Advanced Variants of Systemic Mastocytosis^{1, 5}

Table 8. Conventional Chemotherapy that may be prescribed for Selected Patients with Smoldering and Advanced Variants of Systemic Mastocytosis^{1, 5}

Table 9. Immunotherapy that may be prescribed for Selected Patients with Smoldering and Advanced Variants of Systemic Mastocytosis^{1, 5}

There are several more therapies in the pipeline, including additional tyrosine kinase inhibitors and other targeted therapies.

Sometimes symptoms change, and it becomes necessary to increase or decrease doses of medications, or to add additional medications to a patient’s prescribed protocol. The simplest change made in conjunction with your mast cell specialist can make such a difference in your symptoms! Although it is tempting to change dosing regimens on your own, please always work with your physician to achieve the safest, most effective outcome!