Research Update

    YM BioSciences starts patient treatment in Phase II trial combining

    tesmilifene with Taxotere(R)

 

    - Study to enroll up to 39 women with rapidly progressing metastatic

                              breast cancer -

 

    MISSISSAUGA, ON, June 5 /CNW/ - YM BioSciences Inc. (AMEX:YMI, TSX:YM,

AIM:YMBA), the cancer product development company, today announced that

treatment has been started in its Phase II trial combining tesmilifene with

Taxotere(R) (docetaxel). The trial is being conducted in collaboration with

Sanofi-Aventis and will investigate the effect of this drug combination in

women with rapidly progressing metastatic breast cancer.

    The purpose of the study is to determine if the addition of tesmilifene

to docetaxel has the potential to improve clinical response without increasing

toxicity in patients. The primary endpoint of the trial is pharmacokinetic;

assessing the effect of addition of tesmilifene on the plasma concentration of

docetaxel. YM anticipates enrolment will be completed in calendar Q4, 2006 and

that pharmacokinetic data will be available in calendar Q1, 2007. The

secondary endpoints are overall survival and progression-free survival.

Survival data from this trial will be compared to historical survival data for

Taxotere(R) alone.

    "In the clinic, tesmilifene has been shown to significantly improve the

effectiveness of commonly used cancer chemotherapies, prolonging survival when

compared to chemotherapy alone. Tesmilifene has been shown in both "in vitro"

and "in vivo" preclinical models to allow the specific targeting of multiple

drug resistant cancer cells by anthracyclines, taxanes, vinca alkaloids and

cisplatin. These "smart targeting" effects allow the tesmilifene/cytotoxic

combinations to destroy resistant cancer cells; the growth of non-resistant

cells being retarded or eliminated by the inherent activity of the cytotoxic

agents themselves," said Dr. Paul Keane, Director, Medical Affairs of YM

BioSciences.

    "We expect to report survival data from this study in late 2007. While

early analyses of data from our ongoing pivotal Phase III trial will precede

the conclusion of this Phase II trial, a positive result in this trial would

significantly broaden the commercial applicability of our lead drug," said

David Allan, Chairman and CEO of YM BioSciences.

    The single-arm study is expected to enroll up to 39 women who are

diagnosed with metastatic breast cancer or had their cancer recur within 24

months of their initial breast cancer diagnosis. Patients will be administered

docetaxel every 21 days and tesmilifene will be administered by a single

infusion at the start of each docetaxel cycle. Following a 5-patient dose

escalation component, patients will be treated for up to 29 weeks unless there

is evidence of unacceptable toxicity or disease progression. The study is

being conducted in Europe and the USA.

    Docetaxel is a second-generation taxane that is commonly used to treat

patients with recurrent or metastatic breast cancer.

 

    About tesmilifene

    Tesmilifene is a small molecule drug currently undergoing a 700-patient

pivotal Phase III trial in metastatic and recurrent breast cancer that

completed enrolment in 2005. The trial compares tesmilifene combined with

epirubicin/cyclophosphamide against epirubicin/cyclophosphamide alone in women

with rapidly progressing metastatic and recurrent breast cancer. The trial is

the subject of a Special Protocol Assessment by the FDA and is being conducted

under an adaptive clinical design that provides three pre-planned evaluations

of the data each of which could be sufficient for submission for marketing

approval if the survival targets are achieved. The first interim analysis is

expected to occur in mid 2006. YM has received FDA Fast Track designation for

tesmilifene in advanced breast cancer.

    Separately, an approval has been received from Health Canada to initiate

a randomized Phase II trial in first-line inoperable gastric cancer, where

tesmilifene will be added to standard chemotherapy consisting of anthracycline

(epirubucin), 5-FU and cisplatin and compared with standard chemotherapy

alone. This trial is anticipated to enroll 120 patients and will be conducted

in North America and Korea where gastric cancer incidence exceeds 65,000. A

randomized first-line trial in hormone-refractory prostate cancer combining

Taxotere(R) with tesmilifene is being designed and is expected to be initiated

before the end of 2006. YM has previously announced that it also intends to

complete the design for a Phase III trial in primary (adjuvant treatment)

breast cancer which it also anticipates could be submitted for regulatory

approval before the end of 2006.

 

    About YM BioSciences

    YM BioSciences Inc. is a cancer product development company. Its lead

drug, tesmilifene, is a small molecule chemopotentiator currently undergoing a

700-patient pivotal Phase III trial in metastatic and recurrent breast cancer.

In addition to tesmilifene, YM BioSciences is developing nimotuzumab, an anti-

 EGFr humanized monoclonal antibody, in a number of indications and

AeroLEF(TM), a unique inhalation delivered formulation of the established

drug, fentanyl, to treat acute pain including cancer pain. YM BioSciences is

also developing its anti-GnRH, anti-cancer vaccine, Norelin(TM), and owns a

portfolio of preclinical compounds.

    Except for historical information, this press release may contain forward-

looking statements, which reflect the Company's current expectation regarding

future events. These forward-looking statements involve risk and

uncertainties, which may cause but are not limited to, changing market

conditions, the successful and timely completion of clinical studies, the

establishment of corporate alliances, the impact of competitive products and

pricing, new product development, uncertainties related to the regulatory

approval process and other risks detailed from time to time in the Company's

ongoing quarterly and annual reporting.

   

    For further information: Thomas Fechtner, The Trout Group LLC, Tel.

[phone] x31, Fax [phone], Email: tfechtner(at)troutgroup.com;

James Smith, the Equicom Group Inc., Tel. [phone] x 229,

Fax [phone], Email: jsmith(at)equicomgroup.com

    (YMBA)



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