Understanding MPN Treatment Options | What’s Available for MF, PV, and ET?

 

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Transcript:

Katherine Banwell:

So, what are the types of treatments available for MPNs?  And let’s start with myelofibrosis or MF. 

Dr. Raajit Rampal:

If we had had this discussion five years ago, it would be pretty simple, and it would take a minute or two. And that’s completely changing and that’s amazing, and it’s good for all of our patients.  

Right now, for patients with MF, it depends on what the issue is. If the issue is symptoms or spleen, JAK inhibitors are our first line of therapy. Three approved JAK inhibitors are currently available, two on the first side ruxolitinib (Jakafi) and fedratinib (Inrebic). And pacritinib (Vonjo) can be used for patients with really low platelet counts.  

There is a fourth JAK inhibitor that we expect to be, hopefully, approved in June of this year, momelotinib. So, the landscape is about to complete broaden in terms of just JAK inhibitors. 

But beyond the JAK inhibitors themselves, there are a number of late stage clinical trials that are combining JAK inhibitors with agents that work through a different mechanism that don’t work through inhibition of the JAK pathway. So far, these drugs have all shown promise in early phase trials. Now, the definitive Phase III trials are being done. We have to wait and see what the data tells us. But if these are positive trials, this could completely alter the landscape of MPN. 

Katherine Banwell:

There’s also transplants available, right? 

Dr. Raajit Rampal:

Correct. Transplants for more advanced patients, which comes with some major risks. And so, that has to be thought of very carefully in terms of the risks and benefit. But it is a potentially curative strategy. 

Katherine Banwell:

Let’s turn to polycythemia vera or PV. What types of treatments are available? 

Dr. Raajit Rampal:

It’s really quite a range. So, there are things like phlebotomy and aspirin, which has been the mainstay of therapy for many years. There are drugs like hydroxyurea (Hydrea), interferons, JAK inhibitors. So, ruxolitinib is approved in certain settings for treating polycythemia vera. So, the landscape is broad. There are a lot of questions going on right now with polycythemia vera with regards to how it should best be treated. Is the mainstay of phlebotomy and aspirin really what we should be doing or should we be giving patients treatment earlier on. 

And there is some data to suggest that. There is this drug called ropeginterferon (Besremi) that’s FDA-approved for polycythemia, which was compared in the study to phlebotomy and aspirin.  

And at least the data suggests that there may be better control of the disease and less progression possibly, and it’s a small number of patients, by treating patients earlier. Whereas we would have just given phlebotomy and aspirin. So, it’s something to consider. There are drugs in clinical trials as well that look promising one of which is called rusfertide, which actually works by changing the way iron is used by the body. 

Iron is a key component to hemoglobin and it is, of course, a key component to polycythemia in the sense that we phlebotomize patients to make them iron deficient and that’s how we control the disease. But this is a pharmacological way to do that. So, that drug is now in Phase III trials. So, that may also alter the landscape of treatment of PV in the near future.  

Katherine Banwell:

Finally, how is essential thrombocythemia treated? 

Dr. Raajit Rampal:

So, in some cases, with absolutely nothing as we had talked about a moment ago. There is some thought that in really, really low-risk patients. Maybe you don’t need to do anything except observe them. Whereas most patients are on an aspirin. And beyond that, we have drugs like interferon, pegylated interferon, and hydroxyurea and anagrelide, all of which can be utilized. It’s not entirely clear if there is one distinct first line treatment that is the best but these drugs are all active. JAK inhibitors have been studied in this setting. And to date, the data hasn’t led to their approval but, certainly, people have studied it.   

Katherine Banwell:

Dr. Rampal, how can you tell if a treatment is effective? Are there signs that you look for? 

Dr. Raajit Rampal:

Well, I think it’s a couple of things.  

One, are we meeting the treatment goals in terms of are we controlling blood counts with ET or PV? That’s one of the first principles in management. And with regards to MF, the same thing. Are patients’ symptoms being controlled? Is the spleen being adequately controlled? And then, there’s the symptom burden because just because the blood counts are being controlled, patients may still have symptoms, in which case, they are not being adequately treated. And then, we have to do our best to try to find a treatment strategy that does control their blood counts but also does control their symptoms. So, there is the blood count perspective but there is the symptom perspective as well.