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www.fdanews.com/articles/72750-ym-biosciences-achieves-primary-objective-with-norelin-study

YM BioSciences Achieves Primary Objective With Norelin Study

May 27, 2005

YM BioSciences has announced that Norelin, its anticancer vaccine targeting the gonadotropin releasing hormone (GnRH), has successfully completed a proof-of-concept study in men with hormone dependent prostate cancer (HDPC).

The majority of patients with HDPC treated with Norelin developed antibodies to GnRH, demonstrating the development of an immunological response, which was the primary objective of the trial.

The trial enrolled patients in two stages. In the first stage, 12 patients were enrolled and treated with the company's proprietary formulation of Norelin and were followed for 90 days. In the second stage, four patients were enrolled starting in mid-2004 and followed for 180 days before determining whether they responded. YM originally planned to enroll a total of 12 patients in the second stage, but voluntarily terminated enrollment of the trial when delays in trial implementation resulted in clinical supplies of the drug exceeding stability time-limits. The drug substance demonstrated excellent stability for four years, more than sufficient to consider it marketable.

Patients from the first stage whose testosterone dropped significantly at 90 days were advanced onto a long-term booster program. Seven of the 12 enrolled patients developed anti-GnRH antibodies and two went on to achieve castrate levels of testosterone by day 120. Those two patients received booster doses for approximately two years and are in long-term follow-up. They remain at castrate levels with normalized PSA and have not demonstrated any sign of disease progression at more than 2.5 years.

Three patients from the first stage and three patients from the second stage received at least five doses of the vaccine and these patients were followed for 120 days. All responded to the vaccine, developing antibodies and achieving testosterone suppression. Three of these patients achieved complete castration of testosterone and normalized PSA.