YM BioSciences has enrolled the first patients in its multi-center phase II trial of CYT387 administered twice-daily (BID) for the treatment of myelofibrosis. The trial will further evaluate the safety and tolerability of YM's JAK1/JAK2 inhibitor, as well as its  efficacy in reducing spleen size, improving constitutional symptoms and  reducing transfusion dependence in patients with myelofibrosis.

Six leading academic centers in the U.S. and Canada will recruit  approximately 60 patients in two phases: part I, a dose-escalation  study enrolling successive patient cohorts dosed starting at 200mg BID,  escalating at 50mg BID per cohort; and part II, a dose-confirmation  study evaluating patients at or below the maximum tolerated dose  determined in part I.  Patients in this trial will be evaluated for six 28-day cycles.

In the BID trial, spleen size will be evaluated both by palpation and by magnetic resonance imaging (MRI) for all patients enrolled.

Constitutional symptoms will be assessed using the Myelofibrosis  Symptom Assessment Form (MFSAF). Transfusion histories will be collected for the six-month period prior to enrollment and transfusion independence will be based on both 8-week and 12-week criteria. The effect of CYT387 on plasma levels of inflammatory, fibrogenic and  angiogenic cytokines, and on bone marrow and peripheral blood  cytogenetics will also be assessed.