Aren't clinical responses in MF defined by other criteria besides spleen size?
Myelofibrosis is a chronic myeloid cancer in which bone marrow cells that produce blood cells develop and function abnormally. The result is the formation of scar tissue in the bone marrow (fibrosis), severe anemia that often requires transfusion, weakness, fatigue and an enlarged spleen and liver.
An oncologist friend of mine said it is virtually impossible to believe that there is clearing of fibrosis in the marrow. If that's the case, then we haven't seen a drug like this before. Maybe we need to wait for more mature data to see the full effect of this clearing on constitutional symptoms.