Overview of Treatment Options for Myelofibrosis
Rami Komrokji, M.D.: I think ET (essential thrombocythemia) and PV (polycythemia vera) are similar but myelofibrosis probably is a little bit different, so the spectrum of symptoms and the goals of treatment may be different. I’ll ask you to walk us through how you think of managing myelofibrosis patients.
Ruben Mesa, M.D.: Well, I think that’s very helpful, Rami. I think that was a great description of how we treat ET and PV. Again, we’re trying to use a range of therapies, and we’ll discuss a little later some of the newer therapies. What I do is kind of early MPNs (myeloproliferative neoplasms), and not every patient leaves as an early MPN patient based on risk of blood clots, bleeding, potential symptoms, but they can progress to myelofibrosis. As we mentioned earlier, myelofibrosis in our spleen, difficult symptoms and sometimes lower blood counts has some variable risk of progression to acute leukemia. Now, MF (myelofibrosis) patients can have evolved from ET or PV. Again, as we’re monitoring those diseases, if they start to change, such as a bigger spleen, worsening symptoms, lower blood counts or scarring in the bone marrow, and we think they’ve progressed from MF or they’ve started it, we call it primary myelofibrosis. Now, when we consider treating MF, we do treat it differently than ET or PV, because it has the potential to be life-shortening. Now, it’s not life-shortening in everyone. Our therapies are helping to extend life. Individuals might be diagnosed (at older ages) and they may die of something else, but it does have that potential. Because of that, the first decision we (consider) as your physicians and you as a patient is “Should we pursue a bone marrow transplant?” Bone marrow transplant, it’s synonymous with stem cell transplant, can cure myelofibrosis. However, it’s a very complex therapy. It’s probably one of the most complex medical therapies an individual can undergo. Even in the best of circumstances, there is a real risk that the transplant could potentially be a life-threatening complication. Who do we transplant? We consider that in individuals, the younger you are, the more aggressive we think your myelofibrosis might be. The more fit you are, and the more aggressive you wish to be with your health care, the more we consider it. We will consider it (in ages up to) the late 70s, but as we get older, the risks become higher and the likelihood of it being a good option is lower. That’s a discussion and a thought process that occurs usually in parallel with us deciding on treatment. For treatment, we again consider the risks and benefits and stratify patients accordingly. First, there are low-risk patients who have no symptoms. There’s an occasion when we find someone who came in for a general physical and the spleen was enlarged, and we finally find myelofibrosis, but otherwise, they wouldn’t know they were sick. This is a minority. In these individuals, sometimes we will watch the disease. That is still a small minority of patients. People who have more risk than that and more symptoms, we typically will start on a medicine. Now we have three approved medicines. By far the one that has been used the greatest up to this point because it’s been approved now over 10 years is ruxolitinib. This is a medicine, a pill, that’s given twice a day, and it was approved because of the benefit it had for patients with MF, such as improving enlargement of the spleen. Sometimes the spleen can be under the rib cage on the left side, and sometimes it can be many times larger than it should be. It can cause discomfort, fullness and pain, and because of that, we like to reduce it. It can help with symptoms, and it can even impact the course of the disease; ruxolitinib clearly can have that benefit. It can improve symptoms, help you gain weight and help to improve the other symptoms such as fatigue, night sweats and so on. It likely helps patients with myelofibrosis live longer, and perhaps, in some individuals, even significantly longer than they would have lived otherwise. We know you can take it for a long time. I saw a patient yesterday in-clinic who first went on ruxolitinib in 2009 and has been on it ever since then. That’s dramatically longer than we might have expected that individual to live. It’s really made a big impact. Now, it has limitations. It sometimes can cause anemia, increase the risk of skin cancers and increase the risk of some infections, but it’s a good therapy. Second, we have fedratinib, which was approved much more recently in 2019. It can be helpful like ruxolitinib. It sometimes can be helpful to give if ruxolitinib initially didn’t help. It also can cause anemia, diarrhea or nausea. We usually give medicines for that. It rarely can lower vitamin B1 in the blood, which can cause something called encephalopathy, so we monitor for that. Usually, monitoring for that and giving vitamin B1 helps to nip that in the bud. The third medicine approved much more recently is for the subset of patients with myelofibrosis who have a very low platelet count that increases their risk of bleeding. Ruxolitinib and fedratinib can lower the platelet count, so the having pacritinib is a big plus. We can give it at full dose. We can have benefits for the spleen or for symptoms in individuals with a low platelet count. There are these three options, and some more are on the way. We’ll talk about some of the therapies on the way in a moment.
Transcript edited for clarity.
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