YM BioSciences begins enrollment in CYT387 Phase II trial for myelofibrosis

YM BioSciences Inc. (NYSE Amex: YMI) (TSX: YM) today announced that it 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.

"In the ongoing Phase I/II trial, CYT387 appears to have a favorable safety profile and has produced a clinically beneficial response in a number of our patients. I look forward to evaluating the drug under this alternative dosing schedule as well," said Dr. Vikas Gupta, Principal Investigator for the CYT387 studies at Princess Margaret Hospital, Toronto, Ontario.

Six leading academic centers in the U.S. and Canada will recruit approximately 60 patients in two phases: Part 1, a dose-escalation study enrolling successive patient cohorts dosed starting at 200mg BID, escalating at 50mg BID per cohort; and Part 2, a dose-confirmation study evaluating patients at or below the maximum tolerated dose determined in Part 1.  Patients in this trial will be evaluated for six 28-day cycles.

"The favorable safety profile of CYT387 observed to date provides us with the opportunity to acquire further safety and efficacy data for CYT387 at doses complementary to those evaluated in our ongoing 166 patient Phase I/II trial," said Dr. Nick Glover, President and CEO of YM BioSciences. "Initial data from the BID trial will be used to further enhance our pivotal trial designs, and the substantial volume of patient data from the combined studies will be an important component of any future marketing application."

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.