MPN expert, Dr. Srdan Verstovsek reviews factors that may indicate a treatment change for patients with essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF).
Dr. Srdan Verstovsek
The real definitions of a failure of a given therapy, it’s not easy to come by. Experts in the field, doctors that see a lot of myeloproliferative neoplasm patients, occasionally get together and try to put in place some guidelines. What would be a failure to a therapy mean for patients with ET or PV?
Would that be, for example, polycythemia vera patients too many phlebotomies when you are on hydroxyurea.
Hydroxyurea is a chemotherapy by mouth, should be eliminating need for phlebotomy, should decrease the white cells and platelets, and the spleen enlarged, and improve the quality of life.
If that’s not possible, and you have to define what that means, then you would say, you should change. So, guidelines do exist, which are always used in clinical studies to define the failure and justify a change. But they should also be applied in clinical practice to apply possible.
If you are on hydroxyurea for ET and PV, and you are not controlling blood cell count very well, you can’t take more because there are side effects from hydroxyurea, you should change. Right?
If you see a progression of the spleen, or worsening of quality of life despite the control of the blood cell count, something is wrong, maybe you should change.
In myelofibrosis is similar situation. You may be experiencing a good therapy on JAK inhibitor or anemia medication, but then after a while, spleen starts to grow, quality of worsens, or anemia develops, then you should change.
It’s not as easy to see exactly to define, but you get the point I’m sure because people are different, the benefit extent or benefit is different, pattern of a failure is different, and we have a lot of difficulties in really objectifying what this means to fail.
My approach is when I see a failure developing – nothing happens overnight. You try to modify what you do by adding another medication, adding medications for whatever is causing that failure, or modifying what you’re doing by changing the schedule or the dose. So, not to give up and say, “Oh, it’s not working,” but trying to work with the patient, and with the medications that you have in different way, for benefit to last the longest possible.