What effect does ruxolitinib phosphate have on cytokine-induced STAT3 phosphorylation?

Ruxolitinib phosphate inhibits cytokine-induced STAT3 phosphorylation in whole blood from healthy subjects and patients with myelofibrosis or polycythaemia vera, with maximal inhibition 2 hours after dosing and return to near baseline by 8 hours in healthy subjects and myelofibrosis patients, indicating no accumulation of parent drug or active metabolites.