Robert E. Richard, MD
Dr. Richard: The first thing we as physicians are worried about is patients with PV developing thrombosis. We start prophylaxis with aspirin, as aspirin remains the best treatment for reducing this risk. It is essential to make sure patients with PV understand the importance of taking an aspirin, even at a low dosage.
The second step is trying to control patients’ red blood cell counts. Phlebotomy has been used for this purpose for many decades and continues to be effective. You will find some experts in the field who consider phlebotomy to be the mainstay of treatment for patients with PV, and that it has benefits in and of itself.
However, despite the benefits, phlebotomy can be a little tough on patients. For instance, patients with PV cannot donate blood at a traditional blood center such as Red Cross, and therefore need to go to an actual infusion center. They also must stop their day and travel to a site to receive therapeutic phlebotomy treatment, which is most effective for patients with a blood disorder. I work in Seattle taking care of patients throughout the Northwest, and it is not always easy to find a close location to send patients for phlebotomy. Nevertheless, phlebotomy should be part of the treatment options for patients with PV, especially patients in the high-risk range who have high hemoglobin and hematocrit values.
The third step is controlling hemoglobin and hematocrit levels. Hydroxyurea is our standard of care with strong beneficial data for this purpose.
These are the 3 approaches to treatment we initially discuss with our patients during their first visit. These 3 strategies can improve a patient's life and reduce their risk for thrombosis.
Which treatment do you recommend depending on the patient’s symptoms?
Dr. Richard: The treatment that we offer can vary. The first thing I want to know is how their symptoms respond to aspirin. For instance, symptoms such as erythromelalgia oftentimes respond beautifully to aspirin. Most patients do not have massive splenomegaly—that would give me a high suspicion for myelofibrosis—but they can develop and present with some level of splenomegaly.
If the symptoms are bothersome to the patient, I will probably want to get them on some kind of cytoreduction to see if that is effective. Hydroxyurea, although not as effective as aspirin and associated with adverse effects in some patients, is a good medication to start cytoreductive therapy. The National Comprehensive Cancer Network® (NCCN®) Guidelines suggest that if a patient taking hydroxyurea experiences severe gastrointestinal (GI) toxicity, go ahead and move to a Janus kinase 2 (JAK2) inhibitor or try interferon. JAK2 inhibition with ruxolitinib, in this case, is effective, at least initially for treating splenomegaly. Unfortunately, symptoms sometimes get confused with effects from the medications. You have to use an individualized treatment approach and see what works for each patient.
What are some of the common adverse effects of treatment?
Dr. Richard: As you probably can tell, I never skip aspirin since it is such an important part of treatment for patients with PV. However, I do talk to patients about GI upset and the bleeding risks, such as the potential for GI bleed. Obviously, clotting is what causes an increase in morbidity and mortality, but bleeding can be an important adverse effect with platelets that do not function, or for other issues.
Hydroxyurea is generally well tolerated, but some patients can develop skin issues or ulcers due to GI toxicity. I have a lot of confidence in the use of hydroxyurea, and I use it without hesitation. However, you may have a patient who already has a relatively low neutrophil count or has some level of thrombocytopenia from either liver disease or some other issue, and they just cannot tolerate hydroxyurea. Some other bothersome symptoms include change of taste, skin changes, and brittle nails. It can be tricky. I will attempt hydroxyurea, if needed, but sometimes they just cannot tolerate it.
What happens when a patient cannot tolerate one or all the medications you mentioned?
Dr. Richard: Now that we have JAK2 inhibitors, ruxolitinib is generally my choice for patients who cannot tolerate hydroxyurea, which is more common than maybe we would like. Other problems with hydroxyurea include that it might not work, or phlebotomy combined with hydroxyurea results in cytopenias, or patients have a particularly aggressive form of PV.
There are numerous other JAK2 drug inhibitors on the market for myelofibrosis. The assumption is they probably work as well as ruxolitinib for PV, but right now ruxolitinib is what is approved by the US Food and Drug Administration for these patients.
The other drug that we do not use much is interferon, or now, pegylated interferon. It is a drug that has been around for a long time and worked well in chronic myelogenous leukemia before we had the tyrosine kinase inhibitors. Pegylated interferon is a well-tolerated drug that can be used for patients with PV who are pregnant or could get pregnant. It is not the interferon of our parents or grandparents. We now have options for controlling the disease and its complications, but the hardest thing is to tell patients that none of these treatments are going to cure them or reverse the overproduction of red blood cells in their bone marrow. There has always been discussion about whether there could be some effect of interferon on the actual tumor burden, but that remains to be proven.
Can you go a little bit more into your recommended approach to managing newly diagnosed patients with PV in your day-to-day practice?
Dr. Richard: Oftentimes these patients are identified through our consultation service. It can be hard on the primary care physician to identify whether a patient has secondary or primary PV.
We are lucky now that JAK2 has been identified. The JAK2-V617F and the other exon 12 mutations were identified back in 2006 by several groups and is a great test. With JAK2 along with an erythropoietin test, you can feel confident whether you have identified PV.
PV encompasses a wide variety of syndromes. Patients can come into the office with terrible symptoms, including aquagenic pruritus or erythromelalgia. I have seen young people in their 30s who happen to have a slightly elevated hematocrit and a positive JAK2 test. When this occurs, you try to understand how much the disease is affecting their life, whether they are going to be in a high-risk category or a low-risk category, whether they have had thrombosis, and how their age figures into all of it. To try to figure out this high-risk versus low-risk factor, we use a simple staging system to help determine whether they are going to need cytoreductive therapy or whether you can just start with phlebotomy and see how they do.
Oftentimes in the first visit, I recommend a bone marrow study. Is that going to be true 5 years from now? I am not sure. You know, next-generation sequencing (NGS) is turning into such an important part of determining prognosis in these patients. It helps if you have a great colleague down in hematopathology who can look at the bone marrow as it relates to megakaryocyte morphology, or whether there is early fibrosis.
Although these techniques may not be as prominent in practice today for determining diagnosis, they help us understand the prognosis. A bone marrow study or NGS is particularly useful when you have patients who you are convinced have PV, but it turns out they already have extensive fibrosis and are actually moving more toward the post-polycythemia phase a little faster than you think. While we do not use an allogeneic transplant often, in this scenario we may recommend it. Our primary goal at this point is to try to determine which patients would benefit from a transplant early on and to prepare the patient for this option.
What socioeconomic disparities have you observed in newly diagnosed patients?
Dr. Richard: There are definitely social disparities for people who have low income. I work in a veteran’s hospital where we take care of a lot of people who do not have health insurance, but who come to the VA because they do have benefits. If they are in our system, they get identified and their care is great. However, if they have been out in the regular system without health insurance, oftentimes they get diagnosed late. Identifying and treating patients from low socioeconomic backgrounds is an issue. I think everyone can agree with that.
We have a delicate situation with women veterans. Something that is incredibly painful that I think people should be aware of is the amount of military sexual trauma (MST) that has occurred over the years. These patients are in a unique place of trust with their care providers. They have spent a lot of time not being listened to in a variety of arenas. I see this in young military women who no one expects to have a stem cell disorder. We as health care providers do them a disservice if their complaints lead to referral to a psychotherapist or being prescribed a nonsteroidal anti-inflammatory drug or something like that. As health care providers, we are in a unique position to listen to and accurately evaluate these patients. We have a large population of veterans and, increasingly more women veterans, but I think we can all agree that they need better care, especially if they have suffered from MST. That is what I see in my patient population.
When I was a resident in Baltimore, it was Black people with lower income who did not trust doctors. We still have a lot of work to do.