Tyrosine kinase inhibitors in the treatment of mast cell diseases

Author’s note: The following post is my personal opinion and is based upon publicly available information and not upon any confidential information I have obtained as a result of my job. The ideas described below are directly attributable to me and not to my employer. I am not a medical doctor and this is not medical advice. This information should be used only to better inform yourself prior to speaking with your provider.

Tyrosine kinase inhibitors have been described in literature for over thirty years. The first tyrosine kinase inhibitor, imatinib, was approved by the FDA in 2001. Because it was the first effective therapy known for a fatal disease, chronic myelogenous leukemia, it was fast tracked through the FDA approval process and approved in two and a half months. In the years that followed, newer tyrosine kinase inhibitors were developed by various pharma organizations. The indications for these therapies expanded from CML to include several other diseases, including certain forms of systemic mastocytosis.

Tyrosine kinase inhibitors were developed with the intention of reducing the toxicity seen in older chemotherapy medications. They do this by targeting specific structures on diseased cells. For example, patients with chronic myelogenous leukemia have a genetic abnormality called the Philadelphia chromosome. This is the result of pieces of DNA getting switched around so that genes that aren’t normally next to each other end up stuck together. This forms a gene called BCRABL that tells cells to continually make new cells even when they aren’t needed. Imatinib targets BCRABL. The idea is that only the cancer cells have BCRABL so healthy cells wouldn’t be damaged.

In reality, it’s a lot more complicated than that. The biggest reason for this is that even though healthy cells don’t have BCRABL, they have other things that look like BCRABL. This is actually why imatinib can treat some cases of systemic mastocytosis: CKIT looks like BCRABL. And there are plenty of other proteins on plenty of other cells, some healthy cells, some diseased cells, that look like BCRABL or CKIT. This means that while tyrosine kinase inhibitors are much more targeted than older forms of chemotherapy, they aren’t so targeted that healthy cells don’t incur any damage at all. Sometimes that damage is serious. Sometimes it is irreversible.

In the mast cell sphere, imatinib was originally used for cases of aggressive systemic mastocytosis that did not have the CKIT D816V mutation. Over time, it was also used for other forms of systemic mastocytosis, including mast cell leukemia, systemic mastocytosis with associated hematologic neoplasm, and smoldering systemic mastocytosis. While imatinib was approved for use in people without the CKIT D816V mutation, there were trials on SM patients who did have the mutation. Published reports found it was less effective but did give benefit to some patients with the mutation. To be clear, the published data strongly points to imatinib being more effective in people without the CKIT mutation than in those that do. But there is some evidence that imatinib might have benefit even if you have the mutation.

I sometimes see people telling other patients that it is dangerous to use imatinib if you have the CKIT mutation. The danger for these people is that it might not work well for them. There’s no special risk beyond that. In fact, the current FDA licensing for imatinib is for patients without the CKIT D816V mutation OR patients in whom CKIT status is unknown. This means that sometimes people are put on it without genetic testing so it’s possible that some of the patients have the mutation.

I want to be so, so super clear about the next thing I say because it is so important that people know this. Imatinib, and other tyrosine kinase inhibitors, are chemotherapies. They are licensed as antineoplastic therapies, also known as chemotherapies. When it’s shipped to your house, it arrives there with the label “contains chemotherapy drugs” on the package. Patients taking it are supposed to be consented for chemotherapy so that they fully understand the risks. TKIs are, for sure, kinder, gentler, more targeted chemo drugs. But they are chemo. And they carry a lot of risks associated with chemotherapy.

I have seen patients describe these drugs as “extremely safe”, “harmless”, “unable to damage other cells”, or even “unable to kill cells.” Those ideas are patently false. These medications are not benign. They are serious. They can cause organ damage, especially liver damage. They can suppress bone marrow, resulting in low blood cell counts. They can cause clotting issues. They most certainly can damage other cells and kill cells, targeted and otherwise. There are hundreds of references describing the ways TKIs can do this, mostly by inducing apoptosis, making a cell kill itself. All of this information is publicly available.

The very fact that TKIs are chemo agents and can cause many of the associated issues is the reason why use of TKIs is controversial in the mast cell community. A lot of people believe that use of TKIs is only warranted in the aggressive forms of systemic mastocytosis that can cause organ damage and death. But there is another school of thought that posits that TKIs are appropriate for indolent SM and MCAS, specifically for cases where anaphylaxis is frequent and severe. They argue that these cases present enough risk to life that the benefits outweigh the risks. Still another group feels that TKIs are safe enough to use for control of non life threatening symptoms in patients with indolent SM and MCAS.

It is my personal opinion that there is benefit to trialing TKIs in patients with indolent SM and MCAS for whom disability or risk to life is significant. I think that you have a right to try unproven therapies when your life is at stake. But I also think that because of the risks, they should only be used when more conservative therapies have failed. The sole fact that they are chemo drugs shouldn’t preclude TKIs from consideration for severe cases of MCAS and ISM. Chemo drugs are prescribed in low doses to treat dozens of conditions, especially immune mediated disorders like autoimmune diseases. But I do think they should be a last resort. I do not personally feel that TKIs are appropriate for general symptom management in non life threatening cases.

My opinion can be summed up pretty cleanly as this: these drugs are serious and they should be reserved for serious cases until such time as we have actual data on how TKIs affect these patients. We need studies, not a handful of case reports, to really understand the risks for MCAS and ISM patients using these therapies. But when other treatments fail and there is risk to life, I think it is appropriate to consider TKIs in these populations.

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 83

96. Why are cancer drugs used to treat mast cell disease?

Disclaimer: The following post was written by me in my capacity as a subject matter expert in mast cell disease and author of MastAttack. This is not work product of my position as a Senior Scientist for a large research organization. All below statements are attributable directly to me in my role as author of MastAttack and are in no way attributable to my employer. Information presented here is publicly available and includes no confidential information learned in my capacity as a Senior Scientist for my employer.

  • There are a number of medications used to treat cancers that are also used to treat mast cell disease. Some of those medications are old school chemotherapies, some are newer, targeted chemotherapies, and some help to control the immune system.
  • In mastocytosis, the body makes too many mast cells. If the bone marrow makes way, way too many mast cells, and those mast cells don’t function correctly, the mast cells can act like cancer cells. This can cause the mastocytosis to behave like cancer.
  • Systemic mastocytosis has several subtypes. The least serious forms do not act like cancer.
  • Indolent systemic mastocytosis (ISM) is the least severe form of systemic mastocytosis. ISM has a normal lifespan. While patients with ISM are at risk of dying for anaphylaxis, an important distinction is that patients with ISM do not die because the mast cell disease acts like a cancer. ISM does not act like cancer.
  • Smoldering systemic mastocytosis (SSM) is a moderately serious form of systemic mastocytosis. SSM can shorten lifespan. In SSM, the body is starting to make lots more mast cells than it should. Those mast cells can affect how organs function. SSM acts like an early cancer.
  • SSM requires treatment to stop it from becoming a more serious form of mastocytosis called aggressive systemic mastocytosis (ASM) that acts like a serious cancer. The treatments used to manage SSM are also used in some cancer patients to help fight cancer. These include meds that affect your immune system, like interferon; newer targeted therapies and chemos, like tyrosine kinase inhibitors; and older chemo drugs, like cladribine.
  • Aggressive systemic mastocytosis (ASM) is a serious form of systemic mastocytosis. ASM shortens lifespan significantly. In ASM, the body makes way too many mast cells. The bone marrow churns out so many mast cells into the bloodstream and then the abnormal mast cells get stuffed into various organs. The mast cells cause organ damage and can cause organ failure. ASM is often referred to as being malignant because it behaves just like a cancer. It is also treated like a cancer.
  • As mentioned above, interferon is a therapy that can affect how the immune system works. Interferon is sometimes used for ASM but it is less commonly used in ASM than in SSM. ASM patients need more aggressive treatment. Newer targeted therapies like tyrosine kinase inhibitors and multitarget kinase inhibitors are frequently used in ASM. Some of these newer therapies are FDA approved for treating some ASM patients. Cladribine and hydroxyurea are still common treatments for ASM.
  • Mast cell leukemia (MCL) is the most serious form of systemic mastocytosis. MCL greatly reduces lifespan. MCL causes production of an unbelievable number of mast cells. There are so many mast cells that they cannot all get stuffed into organs like ASM. This means that while there are lots of mast cells in the organs in MCL patients, there are so many mast cells like that there are still tons of them in the bloodstream. This leads to rapid organ failure, leading to death. Mast cell leukemia is cancer. It is treated like cancer with newer therapies like tyrosine kinase inhibitors and multitarget kinase inhibitors, as well as hydroxyurea or cladribine in some cases. As in ASM, some of the newer therapies are FDA approved to treat mast cell leukemia.
  • Sometimes patients with systemic mastocytosis develop a second blood disorder. This is called systemic mastocytosis with associated hematologic disease. Sometimes this second blood disorder is a form of cancer, like chronic myeloid leukemia. In these instances, the other blood disorder would be treated using cancer medications.
  • Mast cell sarcoma (MCS) is a cancerous form of systemic mastocytosis. Patients with MCS rapidly develop MCL and are treated as described above.
  • None of the therapies I mentioned here are indicated for cutaneous mastocytosis. Cutaneous mastocytosis does not behave like a cancer and is not treated like one.
  • In recent years, two other forms of mast cell disease have been described: mast cell activation syndrome and monoclonal mast cell activation syndrome.
  • Monoclonal mast cell activation syndrome (MMAS) is often considered to be a “pre-SM”. It is treated like indolent systemic mastocytosis and does not behave like a cancer.
  • Mast cell activation syndrome (MCAS) is not know to be an early form of SM. Many people live with MCAS for decades without ever developing SM.
  • Despite the fact that mast cell activation syndrome, monoclonal mast cell activation syndrome, and indolent systemic mastocytosis do not behave like cancer, cancer therapies are sometimes used in these patients. They are used when other therapies have failed and their symptoms are still poorly controlled. Generally, they are used when persistent mast cell activation becomes life threatening. In some instances, they may be used when a patient’s symptoms are not life threatening but are very disabling and cause a poor quality of life. In these cases, the patient and their provider make the assessment that they are able to assume the risk of using these medications.
  • There is very little data on the use of chemo and targeted therapies in patients with MCAS, MMAS and ISM, and no cancer therapies are FDA approved for these conditions. However, use of cancer meds for nonmalignant conditions is not that unusual. It is pretty common in autoimmune disease where lower doses of chemotherapy drugs can be effective in controlling the disease. Basically, the idea is that if we know that these therapies help forms of mast cell disease that behave like cancers then it might help those forms that don’t act like cancer.
  • On a number of occasions, I have seen patients discussing the dangers around certain cancer meds that are sometimes used to treat mast cell disease. In particular, I have seen comments that newer targeted therapies “do not kill cells”, “cannot cause organ damage”, and are “harmless.” This is completely untrue. There are thousands of articles on the side effects and complications of all of the meds I have described here. None of them are harmless. Patients need to understand the risks associated with these therapies.
  • I would like to add a note about something sort of related. Xolair is an anti-IgE medication that is used by many mast cell patients. It is a subcutaneous injection and is administered in a healthcare setting. Patients are required to stay in the office for a little while after the shots are given to be sure that they don’t have a bad reaction. Because the patient is monitored in the office after the shot, the provider’s office will bill insurance for the observation period. The old billing code for this often comes up as “chemotherapy observation” because the same code was used for patients who needed monitoring after chemo. This means that patients may see “chemo” on the explanation of benefits from their insurance company. This does not mean that they received chemo. Xolair is NOT chemotherapy. It’s just a quirk of the medical billing. There is now a new code for post injection observation for meds that are not chemo but not everyone has caught up to it. Just figured I would mention this as people ask about it from time to time.

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 82

95. How do you take oral cromolyn?

  • Cromolyn is a mast cell stabilizer. Most mast cell patients are on cromolyn. Currently, it is taken orally for use in the GI tract, or it is taken nebulized for use in the lungs.
  • Cromolyn is an incredibly finicky substance. It sticks to everything. Your body barely uses it: only 2% of cromolyn is actually absorbed in the GI tract and only 5% in the lungs. The cromolyn that is absorbed is actually not the cromolyn that helps stabilize mast cells. The rest basically just sits on top of cells in the GI tract or lungs and stabilizes mast cells that way.
  • In order to maximize benefit from cromolyn, it is important that it not be taken when there is food or medications that cromolyn could stick to. This is mostly an issue for oral cromolyn used in the GI tract. You do not want to take other medications too close to taking cromolyn because the cromolyn may stick to the other med and not be available to stabilize mast cells. You do not want to eat too close to taking cromolyn because the food could stick to cromolyn, making it unavailable to stabilize mast cells, or the food could block the cromolyn from getting to the surface of the mast cells, preventing it from stabilizing them.
  • Oral cromolyn is usually taken 30 minutes before meals and at bedtime for a total of four times daily. Cromolyn should not be taken until two hours or more after eating the previous meal as this is about how long it takes for food to move out of the stomach. It is worth noting that many mast cell patients have gastroparesis or impaired GI motility which can cause food to stay in the stomach longer. There is no particular recommendation on what to do in this instance.
  • Ampules of cromolyn need to be stored at room temperature and protected from light. The ampules should not be taken out of the foil packs until you are using them. They should not be mixed ahead of time.
  • The intended dose for oral cromolyn in mast cell patients is usually 200 mg (two ampules) four times a day. Patients usually do better when they gradually increase the amount of cromolyn they are taking rather than starting at that dose. How slowly they increase varies widely. Patients should speak with their providers about an appropriate dosing schedule. There is lots of information about this in patient groups and forums.

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 79

92. Why is ketotifen not FDA approved? How do I get it?

Ketotifen is a mast cell stabilizer that is also an H1 antihistamine. It is regularly cited by mast cell patients as one of the more effective meds for managing mast cell disease, especially food intolerance. But it can be tricky to get ahold of in the US.

Firstly, ketotifen actually is FDA approved. It is FDA approved in eye drops. However, the formulation typically used by mast cell patients is oral. Oral ketotifen has not been approved in the US, but it’s not because it’s dangerous. It’s because it was never submitted to the FDA for approval. And why was it not submitted? Again, not because it’s dangerous. At the time, the manufacturer did not feel that there was enough of a market to justify the time and expense of an FDA submission when there were so many other H1 antihistamines available both over the counter and with prescription. It’s that simple.

So how do you get ketotifen in the US? You can import it from abroad for personal use as a mast cell patient, but there is an easier way: ketotifen capsules can be bought through compounding pharmacies who order the powder and put it in capsules. The most common strength for capsules is 1mg. Your provider just writes a prescription for it and the compounding pharmacy puts it together for you. As a side note, insurance often does not cover compounded medications so be prepared for that.

Because there wasn’t an FDA submission, there is less safety and dosing information available. In adults, dosing typically starts at 2-3mg a day. Some providers use much higher doses, even going upwards of 20mg per day in some instances. Again, we don’t have study data on this drug in mast cell disease, so conservative dosing is common.

Ketotifen is available as a tablet without a prescription in many countries, including Canada.

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 78

91. How long should it take to know if a medication is working?

  • This topic is controversial and how long to trial meds is not agreed upon. It varies by provider. This is because there haven’t been many studies done on how long it takes to see therapeutic effects in mast cell patients.
  • Firstly, this question is not “how long does it take for a medication to become active after I take it.” This question is how long you should keep taking a new medication to see if it helps your disease.
  • Firstly, when you are trialing a new medication, or even a new medication dose, try as hard as possible to not change anything else at the same time. It is easier to do this for medication that has short term benefits. I realize this is not always possible, and when it is, it is still a pain.
  • However, you really do need to be able to tell if any changes that occur are from the medication change or not. For example, if you are trying a new antihistamine, and two days after you start it, you also increase your dose of another med, and two weeks later you feel better, you are going to have no idea if it was the new antihistamine or the dose increase of the other med that helped.
  • In my experience, this leads to people being on a ton of meds that don’t all help. Some of us are on a ton of meds that actually help and that can’t always be prevented, but a lot of people just keeping adding things on top of one other without being sure they help. This can really complicate things down the line.
  • How long I trial meds has always been determined by how long it takes for them to cause notable changes in clinical symptoms. Because there aren’t a lot of studies on this topic in mast cell patients, it is common to use recommended time frames found in literature for other cells or other diseases.
  • If they have immediate short term benefits, I trial them for two weeks. Medications that block mediators from acting, like antihistamines and leukotriene inhibitors, are in this group.
  • If they have moderate term benefits, I trial them for six weeks. Medications that prevent mediators from being made, like COX inhibitors for prostaglandins or 5-lipoxygenase inhibitors like zileuton, are in this group.
  • If they have long term benefits, I trial them for sixteen weeks. Mast cell stabilizers like cromolyn and ketotifen and biologics like anti-IgE therapies are in this group.
  • If meds have mixed term benefits (like short term and long term effects), I trial them for the longer term.
  • Please note that steroids are a special case here because they have so many effects that are short, moderate and long term. People generally see immediate relief from them but they really are not meds that should be taken regularly if it can be avoided due to the slew of dangerous side effects.
  • These time frames have been recommended to me by my care team but you will need to discuss this with your own care team. I have found literature supporting these time frames necessary to produce clinical changes in other cell types or diseases.
  • I would also like to mention that in the past, I thought that four weeks was the appropriate period for trialing meds with short term benefits like antihistamines. I now feel that a two week trial is sufficient to identify benefits from these meds.
  • Please also note that for advanced systemic mastocytosis, including aggressive systemic mastocytosis and mast cell leukemia, there have been studies that have identified optimal duration of therapy to see a response for interferon and chemotherapies.

 

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 66

80. When is chemotherapy necessary for mast cell disease?

  • For mastocytosis patients, chemotherapy is used for patients with systemic mastocytosis in whom the disease is malignant (aggressive systemic mastocytosis or mast cell leukemia) or seems to be progressing towards a cancerous form of the disease (smoldering systemic mastocytosis). There are very clear cut guidelines for this. Interferon and chemotherapy are used when a patient has smoldering mastocytosis with increasing mast cell counts; aggressive systemic mastocytosis; or mast cell leukemia, in order to kill off mast cells to slow disease progression and extend a patient’s lifespan.
  • A patient who already meets the criteria for systemic mastocytosis, who has two or more B findings, is considered to have smoldering systemic mastocytosis. SSM is a transition state between indolent SM, which has a normal lifespan, and malignant forms of mast cell disease, including ASM and MCL.
  • Having two or more of the following gets you a diagnosis of SSM: mast cell aggregates that take up 30% or more of cells in a bone marrow biopsy, and/or serum tryptase over 200 ng/mL; bone marrow with too many cells in it overall, without evidence of MDS or a myeloproliferative neoplastic disease; or organ swelling that has not yet affected organ function (swelling of the liver without ascites, spleen swelling enough that it can felt by palpation, lymph nodes swollen to 2 cm or larger).
  • Patients with SSM are watched to see if their body is making lots of mast cells quickly, or if their organs are feeling the strain of too many mast cells. One of the way they check this is to see how quickly their tryptase level increases. If their provider feels that their disease is progressing, they receive chemo or interferon to try and knock the disease down enough that they don’t reach the criteria for ASM.
  • Patients are diagnosed with ASM if they meet the criteria for SM and any of the following criteria: the body not making enough blood cells, cytopenia (absolute neutrophil count below 1000/ul, hemoglobin below 10g/dl, or platelets below 100000/ul); swelling of the liver along with free fluid in the abdomen (ascites), elevated liver enzymes, or portal hypertension; swelling of the spleen along with decreased blood cells due to damage in the spleen, excessive production of blood cells by the bone marrow to compensate, and likely resolution if the spleen is removed; malabsorption in the GI tract causing low protein in the blood (albumin) and weight loss; and severe bone dysfunction, causing a series of bone breaks and large osteolytic lesions from mastocytosis.
  • ASM patients are put on chemotherapy or interferon, usually continuously, unless there is evidence that they have killed off enough mast cells to have a less dangerous disease category.
  • Mast cell leukemia patients are on chemotherapy continuously.
  • There is no described use for chemo in cutaneous mastocytosis.
  • There are situations where patients with other disease categories (ISM, MMAS, MCAS) are put on chemo drugs to try and manage symptoms or shock episodes after all other therapies have failed. While this has been mentioned in literature, there have been no studies on it.
  • Chemo drugs should be used as a last resort. They can have significant side effects and complications that cannot always be remedied by stopping the treatment.
  • Please note that while newer, targeted chemos have become more common, they are in fact chemotherapy and carry significant risks despite being more tailored, including the potential for organ damage or failure.

For additional reading, please visit the following posts:

The Provider Primer Series: Diagnosis and natural history of systemic mastocytosis (ISM, SSM, ASM)

The Provider Primer Series: Natural history of SM-AHD, MCL, MCS 

The Provider Primer Series: Mast cell activation syndrome (MCAS)

The MastAttack 107: The Layperson’s Guide to Understand Mast Cell Diseases, Part 27

35. Why are there different sets of criteria for mast cell activation syndrome? What are the differences between them?

To answer this fully, we need to first discuss the history behind some terms.

Mast cell activation syndrome was first used to describe episodes of mast cell mediator release symptoms in a paper published in 2007 (Akin 2007). Specifically, the term was used to detail the experience of patients who had symptoms we commonly associated with mast cell activation, like flushing, hives, and low blood pressure.

However, the patients in this study were all found to have some features of systemic mastocytosis. While they had some of the criteria for an SM diagnosis, they didn’t meet all the criteria. These patients sort of looked like SM and quacked like SM but would not cleanly meet the diagnostic criteria. So the author of that paper made a separate diagnostic category for them. He called it monoclonal mast cell activation syndrome.

The use of the word “monoclonal” is VERY important here. Monoclonal is a medical term that is associated with the body making too many cells at once so that the cells that are made don’t work correctly. Systemic mastocytosis is a condition in which the body makes too many cells at once that don’t work right. It is a monoclonal disorder. So the author of that paper in 2007 is linking monoclonal mast cell activation syndrome to systemic mastocytosis. He thought of it as sort of a “pre-SM” or “early SM”.

Shortly after that 2007 paper was released, another school of thought was proposed by different groups about the nature of mast cell activation syndrome. These groups also linked the term mast cell activation syndrome to symptoms of mast cell activation, like flushing, hives, and all the rest. However, they did NOT link mast cell activation syndrome to monoclonality. This means that these researchers felt that mast cell activation syndrome could be present without a condition where you make too many sloppy cells like systemic mastocytosis. So patients with no evidence of systemic mastocytosis could still have mast cell activation syndrome according to these groups. The two major groups that believed MCAS was distinct from SM were led by Afrin/Molderings and Castells.

Let’s recap:

In 2007, Akin described mast cell activation syndrome as something that happened only in patients that had some evidence of systemic mastocytosis but not enough to be diagnosed with systemic mastocytosis. In order for this group to diagnose you with mast cell activation syndrome, you had to have evidence of systemic mastocytosis. It was an add on diagnosis to SM, sort of like SM with really bad symptoms.

In the years that followed, two groups, led by Afrin/Molderings and Castells, described mast cell activation syndrome as something that was distinct from systemic mastocytosis and could be found in anyone, even if they had no evidence of systemic mastocytosis at all.

Okay. So these two groups agreed that MCAS could happen to anyone. But they differ greatly in how they think MCAS can be diagnosed. For these groups, MCAS is NOT an add on diagnosis to systemic mastocytosis. It is a standalone diagnosis and entity.

So if the term MCAS was already being used, why didn’t the other groups just call their diagnosis something different? There isn’t a good answer to this but it is super common. Things are much more fluidly changing in the time between coining a term and having the diagnosis accepted by a large organization like the CDC so that your insurance can bill for treatment for that diagnosis. It would be great if everyone just used different names for their variants but this just doesn’t always happen.

Castells feels that in order to be diagnosed with MCAS, you have to show mast cell mediator symptoms, response to medications to treat mast cell activation, and evidence of mast cell activation. You also have to rule out every other possible cause of mast cell activation. Keep in mind that your mast cells are normally activated for lots of reasons so this can really difficult to do.

Additionally, this school considers mast cell activation to be evidenced only by elevation of serum tryptase, 24 hour urinary n-methylhistamine or 24 hour urinary prostaglandin D2 or 9a,11b-prostaglandin F2. So if none of these mediators are high, the patient doesn’t meet the criteria for diagnosis.

Afrin’s criteria are harder to explain because he believes that you should provisionally be diagnosed with mast cell activation disease, which can be a few different things, and then it should be narrowed down to mast cell activation syndrome or another mast cell condition.

The key difference between Afrin’s criteria and Castells’ are that he accepts elevated levels of several other mast cell chemicals to prove mast cell activation. Afrin counts toward diagnosis elevation of serum tryptase, 24 hour urinary n-methylhistamine, serum or 24 hour urinary prostaglandin D2 or 9a,11b-prostaglandin F2, 24 hour urinary leukotriene E4, heparin in blood, and chromogranin A in blood. All of these are released by mast cells. But some of them are released by other cells too so it’s not as easy to say for sure that mast cells cause the elevations. Additionally, some of these mediators are REALLY difficult to measure accurately, like heparin. So some people feel that these tests are less reliable to indicate mast cell activation alone.

Let’s talk about puppies for a second because when things get tough, just find a puppy and things will be cool from there on out.

Let’s present these three schools of thought on MCAS as puppies.

Let’s say that Akin is saying that all dogs with 10 spots on them have SM. He’s saying that dogs with some spots, but less than 10, have MCAS. He is also saying that dogs with NO spots CANNOT have MCAS.

Castells is saying that it doesn’t matter how many spots the dog has but it has to have either blue or green eyes to have MCAS. She doesn’t think the MCAS is related to spots but that it is related to specific eye color.

Afrin is saying that it doesn’t matter how many spots the dog has, or what color eyes. He will accept eyes of many other colors if the dog has a lot of symptoms that look like mast cell activation or respond to medications to treat mast cell activation.

I have simplified this as much as possible so it’s easier to understand. For that reason, I have omitted a lot of things. I am in no way saying that what I described here represents everyone’s experience. I am not saying that at all.

If you want my opinion on what MCAS is, and I’m inclined to think you do because you’re on my website reading my thoughts about mast cell disease, I feel that the evidence points strongly towards a space that blends both Afrin’s and Castells’ points. I feel that we should use more mast cell mediators than just serum tryptase, 24 hour urinary n-methylhistamine, serum or 24 hour urinary prostaglandin D2 or 9a,11b-prostaglandin F2. But I personally find the reliability of tests for heparin level to be very problematic and elevations of chromogranin A can be from so many things. I am not AT ALL saying that people diagnosed with these elevated markers do not have MCAS. I professionally develop diagnostics and these tests are just not great.

I also don’t think there’s enough evidence yet to say that mast cell disease can be proven with a biopsy demonstrating a certain number of mast cells per hpf (high powered field, this is a measurement we use for counting things we see under a microscope). I think it is very suggestive of inflammation and mast cell activity. But there are MANY instances in which normal, healthy, asymptomatic patients have a bunch of mast cells/hpf in their biopsies when they are used in studies.

So I’m solidly in the MCAS is its own entity group but don’t fall evenly into one group or the other regarding diagnosis.

Regarding treatment, I land more squarely with Afrin. I believe that if you have tried all of the conventional treatments and continue to have life threatening episodes, you should be able to try more drastic treatments provided you are well supervised by a knowledgeable provider. This is my personal opinion and in no way reflects the views of my employer. I think that if you are constantly anaphylaxing, or have no safe foods, or have dystonic seizures, or can’t stand up, and you have gone through a long list of “reasonable treatments” that you have a right to try to preserve your life and the quality thereof with any means available.

So, yea. MCAS is a can of worms. But we owe it to MCAS patients to have these awkward discussions even though it’s, well, awkward. Patients are falling through the cracks and we owe it to them to identify what criteria would let us catch them so they can get diagnosed and treated sooner.

I’ve tried hard to explain this objectively but if I haven’t done great, let me know in the comments.

For more detailed reading, please visit these posts:
The Provider Primer Series: Mast cell activation syndrome (MCAS)
MCAS: Differing criteria among experts

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 10

I have answered the 107 questions I have been asked most in the last four years. No jargon. No terminology. Just answers.

17. Does mast cell disease impact mood, anxiety, and depression?
Yes. This has been described in literature for over 30 years. In 1986, a paper described a series of patients with systemic mastocytosis who had severe psychiatric symptoms as a result of their disease. It was called “mixed organic brain syndrome”.
Depression, anger, bipolar disorder, attention deficit disorders, anxiety, irritating, and panic disorders have all been associated with mast cell disease.
• One study found that in a group of patients with cutaneous mastocytosis and systemic mastocytosis, 75% of the patients had symptoms of depression. In another study, 60% had symptoms of depression or anxiety.
• Many patients have been diagnosed with a psychiatric condition before learning that they have mast cell disease. For many mast cell patients, managing their diseases lessens the severity of their psychiatric symptoms. Antihistamines have been reported many times to improve these symptoms.
• Mast cells are often sitting right next to nerve cells throughout the body. Mast cells are found in large numbers in the brain. Chemicals released by mast cells can cause psychiatric symptoms.
• Some of the chemicals released by mast cells are specifically intended to talk to nerve cells. Histamine is one such chemical. When histamine is not released in the right amounts at the right times, it can affect how other chemicals are released. Some of these chemicals are also for cells to talk to nerves, like serotonin and dopamine. Mast cells can also release serotonin.

18. Are medications for depression, anxiety or other psychiatric conditions used in mast cell patients?
Yes. As with every medication, only you and your care team can decide if a medication is safe for you. No medication is universally safe or always dangerous.
Benzodiazepines are usually well tolerated in mast cell patients. Benzodiazepines actually interact with mast cells and can make them release fewer chemicals. (Be aware that the IV forms of these medications sometimes have alcohol in them).
SSRIs are sometimes taken by mast cell patients. Mast cell patients should be cautious because they can increase serotonin levels and mast cells can also release serotonin.
• Tricyclic antidepressants are more commonly used in mast cell patients. Tricyclic antidepressants actually work as antihistamines, too.
• Other drugs that can manage psychiatric symptoms, like mirtazapine, olanzapine, and quetiapine, also have antihistamine properties.
For more detailed reading, please visit these posts:

 

Neuropsychiatric features of mast cell disease: Part 1 of 2

Neuropsychiatric features of mast cell disease: Part 2 of 2

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 9

I have answered the 107 questions I have been asked most in the last four years. No jargon. No terminology. Just answers.

15. How is mast cell disease treated?
• There are a number of medications to treat mast cell disease. Mast cells release so many chemicals, some in a large quantity. We are not able to totally stop mast cells from releasing the chemicals so we need to use many medications to block their effects on the body.
The baseline regimen for mast cell patients include antihistamines and mast cell stabilizers. Specifically, patients are usually prescribed two antihistamines that work two different ways. These are called H1 antihistamines and H2 antihistamines. The H in these meds stand for histamine. There are many antihistamine options. Antihistamines stop the histamine from working in the body. Even still, many patients experience histamine driven symptoms
Mast cell stabilizers work by making mast cells less likely to release chemicals. There are fewer options for mast cell stabilizers. Cromolyn is a very common mast cell stabilizer. Ketotifen is both a mast cell stabilizer and an antihistamine. Ketotifen that you can take as a pill is not approved in the US because there was not a market for it so it was never submitted to the FDA. However, patients can get ketotifen in pill form through compounding pharmacies in the US.
• Other types of medication commonly used for mast cell disease that block the effect of mast cell chemicals include leukotriene inhibitors and PAF blockers.
Some medications can stop mast cells from making specific chemicals. These include COX inhibitors, lipoxygenase inhibitors, and corticosteroids like prednisone.
Many patients are deficient in some vitamins or minerals because they don’t absorb them well in the GI tract. Vitamin D and iron are commonly low. Patients often take supplements to replace these deficiencies.
• Chemo drugs are sometimes used to treat severe mast cell disease. These drugs can kill mast cells and/or decrease the amount of chemicals released.
• IV fluids are reported by patients to help with symptoms such as fatigue and swelling.
• There are many other medications that can be used to treat other symptoms.

16. Do I have to take medication if I feel okay?
Mast cell patients are usually recommended to take baseline medications like antihistamines and mast cell stabilizers even if they feel okay. This is for two main reasons: mast cells can damage your body even if you don’t feel it; and if you do not take baseline medications, you will have less protection from a severe reaction and anaphylaxis.
• Many patients have other medications prescribed to be taken as needed. These medications are given when symptoms are bad and do not necessarily have to be taken daily.
• Please speak with your provider to clarify what meds are taken as needed and what meds are taken every day.
For more detailed reading, please visit these posts:

The Provider Primer Series: Management of mast cell mediator symptoms and release

The Provider Primer Series: Mast cell activation syndrome (MCAS)

The Provider Primer Series: Cutaneous Mastocytosis/ Mastocytosis in the Skin

The Provider Primer Series: Diagnosis and natural history of systemic mastocytosis (ISM, SSM, ASM)

The Provider Primer Series: Diagnosis and natural history of systemic mastocytosis (SM-AHD, MCL, MCS)

The Provider Primer Series: Relevance of mast cells in common health scenarios (continued)

Reason for care Post op care
Role of mast cells Mast cells are inherently activated following surgery as they drive tissue remodeling, angiogenesis, and wound repair.[i]

Mast cells are involved in the transmission of pain stimuli.[iii]

Impact of condition on mast cells Mechanical trauma or pressure, such as dressing a wound or palpating the area, can directly induce degranulation and mast cell activation[ii].

Pain can trigger mast cell activation.[iii]

Psychological and physical stress can trigger an inflammatory response that involves mast cell activation.[iv]

Notes regarding condition treatment NSAIDS can trigger mast cell degranulation and cannot be taken by some mast cell patients.[iv]

Codeine and derivatives can trigger mast cell degranulation[v].

Vancomycin, gyrase inhibitors and cefuroxime should be avoided where possible due to risk of mast cell activation.[vi]

Amide caine anesthetics are preferred over ester caines.[vi]

ACE inhibitors and β-adrenergic receptor antagonists (beta blockers) should be avoided. In particular, beta blockers directly interfere with the action of epinephrine and can impede anaphylaxis management.[vi]

Fentanyl and fentanyl derivatives are the preferred narcotic for mast cell patients due to low risk of degranulation. Hydromorphone and oxycodone are suggested by some authors and see use in mast cell patients.[vi]

Benzodiazepines can provide anxiolytic and anticonvulsive support in mast cell patients are needed.[vi]

IV contrast poses significant to mast cell patients due to the high risk of systemic degranulation. If required, premedication is advised.[vi]

Adhesive allergy is not unusual and patients may require specific occlusive dressings, tapes, or wound glue.

Notes regarding mast cell treatment Antihistamines and mast cell stabilizers can be helpful in mitigating common post op symptoms such as opiate induced itching and nausea. COX inhibitors can help with pain management.[vii]
Special considerations for mast cell patients Mast cells are the largest reservoir of endogenous heparin. Patient should be monitored for coagulopathy.[viii]

Mast cells contribute significantly to post operative ileus.[ix]

Intestinal manipulation directly results in mast cell degranulation.[ix]

 

Reason for care Hypertension
Role of mast cells Mast cell mediators can impact blood pressure. Histamine acting on H2 receptor can promote hypertension.[xi]

Renin, chymase, and carboxypeptidase A all participate in hypertension by dysregulation of angiotensin II.[xi]

9a,11b-PGF2, the degradation product of prostaglandin D2, thromboxane A2, and leukotrienes increase blood pressure.[xi]

Impact of condition on mast cells Dysregulation of angiotensin II and renin levels can affect mast cell behavior.[x]
Notes regarding condition treatment ACE inhibitors and β-adrenergic receptor antagonists (beta blockers) should be avoided. In particular, beta blockers directly interfere with the action of epinephrine and can impede anaphylaxis management. Alternatives include calcium channel blockers, renin inhibitors, and ivabradine, among others.[vi]
Notes regarding mast cell treatment Several mast cell medications can impact levels of histamine, renin, and angiotensin II, all of which can affect blood pressure.
Special considerations for mast cell patients Mast cell patients taking β-adrenergic receptor antagonists (beta blockers) should carry a glucagon pen to increase efficacy of epinephrine in anaphylaxis.[xi]

As many as 31% of patients with mast cell disease demonstrate elevated arterial blood pressure secondary to mast cell activation. These elevations may be episodic or chronic.[xi]

Mast cell patients may also have hyperadrenergic postural orthostatic tachycardia syndrome (hyperPOTS), a condition that can cause hypertension.[xii]

 

Reason for care Heart disease
Role of mast cells Renin, chymase, and carboxypeptidase A all participate in hypertension by dysregulation of angiotensin II, contributing to evolution of arrhythmia.[xi]

Prostaglandin D2, VIP, PAF, IL-6 and nitric oxide are all vasodilating and can contribute to tachycardia.[xi]

Tryptase, histamine, PAF, IL-10, TNF, IL-4, IL-6, FGF, and TGFB can contribute to heart failure.[xi]

Mast cells participate in the formation, destabilization and rupture of atherosclerotic lesions.[xiii]

Histamine release is associated with acute coronary syndromes such as Kounis Syndrome, commonly known as “allergic MI” or “allergic angina”.[xiv]

Leukotriene C4, adrenomedullin, tryptase and chymase participate in the formation, destabilization and rupture of aneurysms.[xiii]

Impact of condition on mast cells Heart disease, especially heart failure, can disrupt release of catecholamines including norepinephrine.[xv] Norepinephrine dysregulation can impact mast cell behavior.

Dysregulation of angiotensin II and renin levels can affect mast cell behaviorx

Notes regarding condition treatment NSAIDS can trigger mast cell degranulation. Some mast cell patients are unable to take them.xx

Acetaminophen is generally recommended for use in mast cell patients.[iv]

ACE inhibitors and β-adrenergic receptor antagonists (beta blockers) should be avoided. In particular, beta blockers directly interfere with the action of epinephrine and can impede anaphylaxis management. Alternatives include calcium channel blockers, renin inhibitors, and ivabradine, among others.[vi]

Notes regarding mast cell treatment COX inhibitors are routinely taken by mast cell patients and may provide relief of prostaglandin induced symptoms.[vi]

Several mast cell medications can impact levels of histamine, renin, and angiotensin II, all of which can affect blood pressure.

Epinephrine can provoke myocardial ischemia, prolong QT interval, and exacerbate coronary vasospasm and arrhythmia.[xiv]

Special considerations for mast cell patients Over 20% of systemic mastocytosis and mast cell activation syndrome patients experience palpitations and supraventricular tachycardia.[xi]

Prostaglandin D2 can cause tachycardia. PGD2 is associated with late phase allergic response and symptoms may be delayed for several hours after allergic event.[xi]

One study showed that 12/18 mast cell activation syndrome patients showed diastolic left ventricular dysfunction.[xi]

Mast cell patients may also have postural orthostatic tachycardia syndrome (POTS), a condition that can cause blood pressure and heart rate irregularities.[xii]

 

Reason for care Chest pain
Role of mast cells Mast cells participate in the formation, destabilization and rupture of atherosclerotic lesions.[xiii]

Histamine release is associated with acute coronary syndromes such as Kounis Syndrome, commonly known as “allergic MI” or “allergic angina”.[xiv]

Leukotriene C4, adrenomedullin, tryptase and chymase participate in the formation, destabilization and rupture of aneurysms.[xiii]

Mast cells participate in esophageal inflammation in several models, including from acid reflux.[xvi]

Mast cells contribute to GI dysmotility which can cause esophageal spasms.[xvii]

Mast cells are involved in the transmission of pain stimuli.[iii]

Impact of condition on mast cells Pain can trigger mast cell activation.[iii]

Psychological and physical stress can trigger an inflammatory response that involves mast cell activation.[iv]

Notes regarding condition treatment NSAIDS can trigger mast cell degranulation. Some mast cell patients are unable to take them.xx

Acetaminophen is generally recommended for use in mast cell patients.[iv]

Fentanyl and fentanyl derivatives are the preferred narcotic for mast cell patients due to low risk of degranulation. Hydromorphone and oxycodone are suggested by some authors and see use in mast cell patients.[vi]

Benzodiazepines can provide anxiolytic and anticonvulsive support in mast cell patients are needed.[vi]

ACE inhibitors and β-adrenergic receptor antagonists (beta blockers) should be avoided. In particular, beta blockers directly interfere with the action of epinephrine and can impede anaphylaxis management. Alternatives include calcium channel blockers, renin inhibitors, and ivabradine, among others.[vi]

Notes regarding mast cell treatment COX inhibitors are routinely taken by mast cell patients and may provide relief of prostaglandin induced symptoms.[vi]
Special considerations for mast cell patients Mast cell patients may experience GI dysmotility which can cause esophageal spasms.[xviii]

Mast cell patients sometimes have eosinophilic esophagitis, causing esophageal spasms, food impaction, and pain.[xix]

Over 20% of systemic mastocytosis and mast cell activation syndrome patients experience palpitations and supraventricular tachycardia.[xi]

Prostaglandin D2 can cause tachycardia. PGD2 is associated with late phase allergic response and symptoms may be delayed for several hours after allergic event.[xi]

One study showed that 12/18 mast cell activation syndrome patients showed diastolic left ventricular dysfunction.[xi]

Mast cell patients can present with Kounis Syndrome. Management of Kounis Syndrome relies upon addressing both cardiovascular aspects of the episode as well as allergic aspects.[xiv]

Costochondritis can occur in mast cell patients and may present as chest pain.

Mast cell patients may also have postural orthostatic tachycardia syndrome (POTS), a condition that can cause blood pressure and heart rate irregularities.[xii]

IV contrast poses significant to mast cell patients due to the high risk of systemic degranulation. If required, premedication is advised.[vi]

References:

[i] Douaiher J, et al. (2014). Development of mast cells and importance of their tryptase and chymase serine proteases in inflammation and wound healing. Adv Immunol, 122, 211-252.

[ii] Zhang D, et al. (2012). Mast-cell degranulation induced by physical stimuli involves the activation of transient receptor-potential channel TRPV2. Physiol Res, 61(1), 113-124.

[iii] Chatterjea D, Martinov T. (2015). Mast cells: versatile gatekeepers of pain. Mol Immunol, 63(1),38-44.

[iv] Dewachter P, et al. (2014). Perioperative management of patients with mastocytosis. Anesthesiology, 120, 753-759.

[v] Brockow K, Bonadonna P. (2012). Drug allergy in mast cell disease. Curr Opin Allergy Clin Immunol, 12, 354-360.

[vi] Molderings GJ, et al. (2016). Pharma,ological treatment options for mast cell activation disease. Naunyn-Schmiedeberg’s Arch Pharmol, 389:671.

[vii] Molderings GJ, et al. (2011). Mast cell activation disease: a concise, practical guide to diagnostic workup and therapeutic options. J Hematol Oncol, 4(10).

[viii] Carvalhosa AB, et al. (2015). A French national survey on clotting disorders in mastocytosis. Medicine (Baltimore), 94(40).

[ix] Peters EG, et al. (2015). The contribution of mast cells to postoperative ileus in experimental and clinical studies. Neurogastroenterol Motil, 27(6), 743-749.

[x] Biscotte SM, et al. (2007). Angiotensin II mediated activation of cardiac mast cells. The FASEB Journal, 21(6).

[xi] Kolck UW, et al. (2016). Cardiovascular symptoms in patients with systemic mast cell activation disease. Translation Research, x, 1-10.

[xii] Shibao C, et al. (2005). Hyperadrenergic postural tachycardia syndrome in mast cell activation disorders. Hypertension, 45, 385-390.

[xiii] Kennedy S, et al. (2013). Mast cells and vascular diseases. Pharmacology & Therapeutics, 138, 53-65.

[xiv] Kounis NG. (2016). Kounis Syndrome: an update on epidemiology, pathogenesis, diagnosis and therapeutic management. Clin Chem Lab Med, 54(10), 1545-1559.

[xv] Florea VG, Cohn JN. (2014). The autonomic nervous system and heart failure. Circulation Research, 114, 1815-1826.

[xvi] Morganstern JA, et al. (2008). Direct evidence of mast cell participation in acute acid-induced inflammation in mice. J Pediatr Gastroenterol Nutr, 46(2), 134-138.

[xvii] De Winter BY, et al. (2012). Intestinal mast cells in gut inflammation and motility disturbances. Biochimica et Biophysica Acta – Molecular Basis of Disease, 1822(1), 66-73.

[xviii] De Winter BY, et al. (2012). Intestinal mast cells in gut inflammation and motility disturbances. Biochimica et Biophysica Acta – Molecular Basis of Disease, 1822(1), 66-73.

[xix] Nurko S, Rosen R. (2010). Esophageal dysmotility in patients with eosinophilic esophagitis. Gastrointest Endosc Clin N Am, 18(1), 73-ix.