Revised assessment of response and long-term discontinuation rates among 111 patients with myelofibrosis treated with momelotinib or ruxolitinib

There are several reports in LEUKEMIA on the efficacy of JAK2-inhibitors such as ruxolitinib, in persons with MPN-associated myelofibrosis. Few doubt these drugs reduce spleen size and relieve symptoms in many if not most persons with these problems. More controversial are response rates and duration and, critically, whether these drugs alter the disease biology in such a way as to improve survival. Data from randomized trials are complex as discussed in a recent commentary. This is a critical issue. If JAK2-inhibitors substantially alter the biology of MPN-associated myelofibrosis, we need to consider giving them to many or most persons with the disease whether or not they have symptoms. If, however, these drugs only treat symptoms, they are useful in persons with these problems but not everyone.