Comparing Momelotinib and Ruxolitinib in People With Untreated Myelofibrosis and Low Blood Cell Counts

Exclusion criteria

• ✕. Spleen volume decrease \<10% or spleen volume increase of any volume from baseline MRI (or CT) in response to initial treatment (momelotinib or ruxolitinib) from baseline MRI (or CT) at week 24.
• ✕. ≥ 3 units of RBC transfusions during any rolling 8-week period starting at or after week 16 preceding Step 2 registration OR hemoglobin \< 8 g/dL on two consecutive measurements at least 1 week apart during any rolling 8-week period starting at or after week 16 preceding Step 2 registration.
• ✕. Unacceptable toxicities attributed to initial treatment (momelotinib or ruxolitinib) of grade ≥ 3 (or grade \< 3 if determined clinically significant by treating physician) as determined by treating physician.
• ✕. Unable to maintain total daily ruxolitinib dose ≥ 20 mg due to cytopenias or intolerance (crossover to momelotinib only).