How is the effectiveness of JAK2 inhibitors monitored in myelofibrosis patients?

How is the effectiveness of JAK2 inhibitors monitored in myelofibrosis patients?

In my practice, I measure efficacy from the patient perspective clinically and potentially using imaging. So I ask my patients, how do you feel after starting the JAK2 inhibitors? Do you feel better or do you feel worse?

The majority of my patients do feel that the JAK2 inhibitors make a very meaningful difference in their quality of life, particularly with pain in the abdomen from symptomatic splenomegaly or from a reduction in night sweats, fevers, or abnormal weight loss. Potentially, some of the patients feel that their energy level increases from the JAK2 inhibitors as well, too.

Because of the reduction in the spleen size from the JAK2 inhibitors, we typically try to palpate the spleen on physical exam, but alternatively, we can look with some type of radiological imaging, such as a spleen ultrasound or a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan as well.

There are other surrogate markers that we look at for efficacy. There is some data to suggest that ruxolitinib and other JAK2 inhibitors could be disease-modifying, which is a very hot topic nowadays. What I mean by disease-modifying is that some signals, such as the mutation, could decrease or even disappear with some of these JAK2 inhibitors. The amount of fibrosis that is in the bone marrow biopsy could decrease or disappear from these JAK2 inhibitors, and potentially the overall survival could be lengthened from these JAK2 inhibitors.

But right now I just look at the symptoms and a lot of those really more interesting disease-modifying or even survival questions. They really need to be ironed out in larger prospective studies.