YM BIOSCIENCES PROVIDES UPDATE ON BREAST CANCER TRIAL

YM BioSciences announced that the independent data safety monitoring board (DSMB) for the company's pivotal Phase III trial of tesmilifene in patients with metastatic or recurrent breast cancer has notified the company that the milestone of 320 events required for the third interim analysis in its pivotal Phase III trial has occurred.

Since the last "data sweep" was completed in November 2006, the DSMB advised the company to conduct a further data sweep to bring the survival data current prior to performing the third interim analysis. This data sweep is ongoing, and the company expects this work to be completed and to have a formal recommendation from the DSMB in February. A data sweep is conducted on a periodic basis prior to each interim analysis.

"Because of the interest in this third analysis and expectations that it might occur this month, we decided to confirm that the threshold number of events has been reached," David Allan, chairman and CEO of YM BioSciences, said.

The pivotal Phase III trial compares the survival of patients treated with tesmilifene combined with epirubicin/cyclophosphamide to epirubicin/cyclophosphamide alone in women with rapidly progressing metastatic and/or recurrent breast cancer. The trial, which completed enrollment of 723 patients in September 2005, is the subject of an FDA special protocol assessment and fast-track designation.

The trial is being conducted according to a sequential design that permits a number of planned interim analyses and the trial will continue until one of two specific statistical conditions is satisfied. At each analysis, the hazard ratio between the tesmilifene-containing treatment arm and the control arm is calculated and then reviewed by the DSMB. The trial may be concluded if either the tesmilifene-containing treatment arm is superior to the control by a specified margin or it is determined that such evidence is not going to be found. If the evidence is insufficient for either conclusion to be drawn, then the trial continues until the next analysis. At the first and second interim analyses, the DSMB recommended that the trial continue as planned.