Case Studies in Myeloproliferative Neoplasms - Episode 18

Case 3: Molecular Profile and Initiation of Therapy in ET

Ruben Mesa, MD, and panel discuss the role of molecular profile in treatment decision-making.

Ruben Mesa, MD: That was a wonderful discussion, Stephen. We’re building. We’ve been chatting all day about polycythemia vera and myelofibrosis. How does ET [essential thrombocythemia] fit into the mix? One of the big differences I see is that this is the only of the 3 that we’ve discussed where the molecular profile is a strong consideration in the current NCCN [National Comprehensive Cancer Network] guidelines regarding initiation of therapy. There’s a difference between the presence of a JAK2 mutation and the presence of CALR, with MPL being a relatively small percentage. Jamile, how does JAK2 vs CALR impact your treatment decisions in ET?

Jamile M. Shammo, MD: We all know that CALR-positive patients tend to do well. If I had a JAK2-positive patient with ET, I would be more cognizant of adding aspirin to their treatment. With CALR patients, I’d be less inclined—especially if they are younger—because I am impressed by the higher risk of bleeding that could come with CALR as their platelet count tends to be a little higher. That’s what I typically do in this patient population when it comes to their treatment.

Ruben Mesa, MD: I agree as well. There’s a difference between the two. I will point folks to the NCCN guidelines. It’s almost an asterisk, but it’s a key one, that low-risk patients who are symptomatic may benefit from cytoreduction. It’s wrong to think of ET as only a disease of thrombosis. There are a lot of individuals—not all; less than half—who can be quite symptomatic with the disease, and it’s only better if they are cytoreduced. When it comes to asymptomatic patients who are very low risk, absolutely. But be mindful of those symptoms. They are an important part of the equation.

This transcript has been edited for clarity.