Example case

Patient:	68-year-old man with PMF experiencing night sweats, fatigue, anemia and splenomegaly.
Diagnosis:	PMF, high risk by IPPS.
Treatment:	Initially treated with hydroxycarbamide, but his spleen size continued to increase, symptoms persisted and anemia worsened, such that he required a transfusion. His spleen was palpable 26 cm below the costal margin.
	Patient was enrolled in the COMFORT-II study, and treated with ruxolitinib 15 mg b.i.d. based on his baseline platelet count of 110 × 109/l.
	The patient experienced an improvement in sense of well-being, and his spleen length was reduced 2 cm on palpation.
Management:	After 12 weeks of ruxolitinib therapy, hemoglobin levels remained stable, but his platelet levels decreased to 75 × 109/l.
	The dose of ruxolitinib was reduced to 10 mg b.i.d., and thereafter, to 5 mg b.i.d. as his platelet count continued to decrease.
	The patient’s platelet count remained between 45 and 55 × 109/l (Figure 2), his spleen enlarged beyond baseline and symptoms returned.
Outcome:	After discussion with the patient, he was withdrawn from ruxolitinib therapy since frequent hospital visits to monitor thrombocytopenia were burdensome, and the patient seemed to have little benefit because of continued dose reductions and interruptions. Symptoms worsened once ruxolitinib was finally stopped, and he was offered hydroxycarbamide. He then transferred to another clinical trial of a different agent.
Commentary:	Due to thrombocytopenia, this patient was not achieving target response to ruxolitinib. He was subsequently enrolled into a clinical trial with a different JAK inhibitor and is tolerating this agent. This, perhaps, reflects a parallel to chronic myelogenous leukemia therapy in which some tyrosine kinase inhibitors seem to better suit some patients in terms of tolerance or comorbidities.