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Agents Used to Combat MPNs

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Published on April 11, 2014

Dr. Jorge Cortes of MD Anderson Cancer Center provides an overview of the current available treatments for myeloproliferative neoplasms (MPNs). He discusses the ultimate goal of treatment, elimination of the disease, which is difficult to do, and the goal thereafter—control the symptoms or the problem the patient is having. Dr. Cortes goes on to discuss specific treatments—such as anagrelide, interferon, and chemotherapy, particularly hydroxyurea—how these medicines work, and how they are being used effectively.



The University of Texas MD Anderson Cancer Center


The University of Texas MD Anderson Cancer Center

Transcript | Agents Used to Combat MPNs

Please remember the opinions expressed on Patient Power are not necessarily the views of MD Anderson Cancer Center, its medical staff or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

Andrew Schorr:        

Dr. Cortes, give us the overview of how you treat these illnesses today.

Dr. Cortes:  

Well, I think that one of the advantages that we have now is that we’re starting to understand what these diseases are, what they do, why they behave the way they behave. And we’re trying to come up with better ways to treat them. Our menu is still somewhat limited today, but I think it’s growing. And not only that, but we’re learning how to use it better. So this list shows certainly the most commonly used agents that we have today. There are others, and we can talk about them little by little as the conversation goes on.

But let’s talk about these ones because I think that represents the great majority of medicines that any of you may have heard about or use today, outside of a clinical trial. So if we start with essential thrombocythemia, again, here what you have is an excess of platelets. And when you have an excess of platelets, remember we said the platelets help you with the clotting. And so if you have too many platelets, you can have a high risk of clotting. And that happens for two reasons. Number one is because the platelets tend to clot.

That’s their function, that’s what they do. So if you have too many, they can clot—and two, because it makes the blood thicker. Essentially, the blood is water and solid matter—the cells. If you have water and any solid, you know, whether it’s sugar or whatever, if you have too much of the solid, it becomes thicker, right? So that’s why it doesn’t go through those little veins and arteries. That’s what Dr. Mesa explained as a micro-vascular disease, you know, the littler, the smaller the vein, the more difficult it’s going to be when it’s too thick.

So the first thing that we try to do with essential thrombocythemia is to say, well we have too many platelets, let’s decrease the number of platelets. Well that’s an anagrelide (Agrylin). An anagrelide drops your blood pressure, drops your platelets. Of course, it drops your blood pressure. So many of you, if you have used that, may have noticed that, if you take an anagrelide, sometimes you feel a little dizzy, you feel a little, and that’s because it can drop your blood pressure.  

And many times we ask the patients that it’s perhaps better to take it at night when you’re going to go to bed or something, so that initial effect of a little bit trends in drop, it can be bad. Now the doses that use are very, very tiny compared to what you need to drop your blood pressure. So for the most part, it’s a very safe drug in that regard. But it does have a little bit of that dizziness, a little, because there’s a very transient and usually mild, but that’s that effect. That’s all that this drug does. It drops the blood, it drops the platelet count.

It doesn’t eliminate the disease. And here we’re going to making a distinction about two things that you pursue when you’re doing a treatment. One thing is, of course, the ultimate goal of a treatment is to eliminate the disease. Whatever that is, whatever disease you have, you want to eliminate the disease. Now don’t tell your doctors, but we doctors are terrible. We eliminate very few diseases. I mean, think about it. We don’t eliminate your blood pressure problem. We control them. But we don’t eliminate them.

But if you control them, you can live a normal life. So it’s not that bad. But that’s one thing you try to do with a disease, eliminate the disease. The other one is to control the symptoms, control the problems that come with that. You know, if you, for example, the cholesterol, you know, if you have high cholesterol, you’re going to have heart attacks and things like that. If you have very high platelets, you can have a lot of clots and clots in areas that could be even life threatening.

So you want to control those things or the symptoms associated with that. So that’s what an anagrelide does. It doesn’t eliminate the disease. There’s no way I can tell you, you take an anagrelide, your essential thrombocythemia is going to be eliminated, you’re going to be cured and forget about it. You don’t have essential thrombocythemia anymore. No, that’s not the case. You still have it. We’re just controlling your platelets—very important distinction but very, you know, very important function.

Because, especially these diseases that, by themselves, move very, very slowly, you could have a normal life if as long as we can prevent you from having one of these serious complications, these clots, these thrombocyte affects. Hydroxyurea. Hydroxyurea is essentially chemotherapy. It’s a very, very, very old chemotherapy. It’s been around for many, many years. It’s a very mild chemotherapy.

And, you know, when we hear the word, chemotherapy, we always think about losing hair, you know, a lot of nausea, a lot of vomiting, mouth sores and all of these things. But not all the chemotherapies are the same. You know, it’s not the same to have, you know, if I tell you, you know, you’re going to have wine, not all the wine is the same. You know, if you’d have a little bit of the wine that they use in church and, you know, a shot of tequila, it’s not the same, right? I mean, it’s all alcohol, but it’s not the same.

Same thing with these medications, you know? Chemotherapy, it’s not all chemotherapy. There are chemotherapies that have a lot of problems and other ones that are very mild. Hydroxyurea is a very, very, very mild chemotherapy, but it’s very effective. The main thing it does is it controls the counts, the blood counts. It can lower any of them. It’s not very specific. So if your problem is that the platelets are very high, Hydroxyurea (Hydrea) doesn’t know how to just affect the platelets and not some of the others. It tends to affect the ones that are growing faster.

That’s what chemotherapy in general does, affects more the cells that are growing faster. And, of course, cancers grow faster than normal tissues. Therefore, we see more of a benefit in the cancer cells. So same here, you know, the cells that are growing faster may be a little bit more sensitive, so we may see a nice drop of the platelets and little or no effect on the hemoglobin or the white cell count. But if you push the drug too much, you certainly can see that effect. But again, that’s what this drug does. It drops your platelets. It doesn’t eliminate the disease.

It doesn’t completely cure, if we’re going to use that word. But it does control the platelets so that you don’t have your first main problem with essential thrombocythemia and don’t develop those clots. So we look for the patients that have this high risk of developing clots. Then you have interferon. What is interferon? Interferon is a substance that we all make. It’s part of our immune system. We all make interferon. Our body makes interferon.

This is one of these medicines that we take from our own body, we learn what they do, and we then produce them so that we can make them into medications. But it’s the same thing that our body makes. We have several of those. Insulin. If there’s anybody who has diabetes here, insulin is essentially not a medicine. Insulin is something our body our makes. And we’ve just fabricated it in a laboratory and then give it back to patients who don’t have enough insulin.

In some instances, we use the hormones that stimulate the production of red cells and white cells. Of course, we don’t use them in these diseases, but those are all examples of medications that are things that our body makes, and we just take advantage of that and use them as medicines. Well, interferon is one of those, Interferon, our body makes interferon. It’s part of our immune system. It’s a reaction to certain infections, particularly viral infections. We make more interferon.

But we’ve learned that interferon can control some of these diseases. All of these myeloproliferative neoplasias, there is a role for interferon to control these excessive production of cells. The other myeloproliferative neoplasias that’s not here is chronic myeloid leukemia. And if we added that here, you know, we have very specific treatment, but each interferon works in that. So all of them, we can use interferon to treat this disease.

Now the interferon, in comparison to the other two that I described, anagrelide and hydroxyurea, which are pills, this is a shot. We’ve learned how to do interferon better in the laboratory because one of the problems is, number one, it was a daily shot when we started doing interferon, and it had a lot of side effects. It gives these, like a flu, part of what gives us the feeling of a flu, you know, part of our reaction to an infection with a virus, is that we make interferon. So, patients, when you gave them interferon, they feel like a flu.

And then long term, there’s fatigue, there is a little bit of difficulty with thinking. There could be depression. There are some potential side effects of interferon. So we’ve developed new formulations of interferon that have much less of that. There’s a formulation that’s called pegylated interferon. Pegylated just means that we attached another molecule to the interferon that makes it live longer. And with that, for example, we only have to administer, let’s say, once a week—much better than having to do it every day, especially because it’s a shot.

And also it has far fewer side effects. So we see that it’s much better tolerated. Those symptoms may still happen but much less than when we used the regular interferon in the past. And we know that it can control the excessive production of the platelets. Generally speaking, we tend to go with the pills first and then we go the interferon. There are variations of the theme and as we’ve emphasized many times, there’s always a patient’s need that determines what you use first.

But, in general, I think, we tend to use more of the pills first and perhaps hydroxyurea and then. But there is a role for interferon in some patients.

Please remember the opinions expressed on Patient Power are not necessarily the views of MD Anderson Cancer Center, its medical staff or Patient Power. Our discussions are not a substitute for seeking medical advice or care from your own doctor. That’s how you’ll get care that’s most appropriate for you.

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