JAK-inhibitor-naive patients, treatment start with ruxolitinib less than 14 days prior to the baseline visit

Patients pretreated with a JAK-inhibitor for more than 14 days prior to the baseline visit

Prospective observational study. There is no treatment allocation. Patients administered Jakavi by prescription and administered according to the SmPC.

Evaluation of all occurring adverse events, serious adverse events and serious and non-serious adverse drug reactions

Spleen size (or volume) reduction was measured by palpation

The ECOG performance status is a scale used to assess how a patient's disease is progressing, assess how the disease affects the daily living abilities of the patient, and determine appropriate treatment and prognosis.

The grade ranges from 0 (fully active, able to carry on all pre-disease performance without restriction) to 5 (dead).

Number of patients with change in constitutional symptoms was collected

The MPN-SAF questionnaire contains important questions that cover MF-specific symptoms whose analysis is part of the standard of care. It includes disease related symptoms each scored from 0 (absent) to 10 (worst imaginable). Total Scores range from 0-100, with higher scores indicating a greater number of symptoms and severity.

This questionnaire consists of questions measuring physical function, physical role limitation, pain, general health, vitality, social function, emotional role limitations, and mental health status. The scores that can be obtained from the scale vary between 0 and 100 and the increase in the scores indicates that the quality of life is high.