Do you adjust the dose of ruxolitinib in primary myelofibrosis based on hemoglobin?  

This is a tough question. It generally depends on how bad the anemia is. You can expect at least a gram (or more) drop in the hemoglobin when starting ruxolitinib, so baseline hemoglobin is important. Also, assuming that the patient is symptomatic, you would want to reduce the dose as little as poss...