Research Update

    YM BioSciences announces preclinical data confirming nimotuzumab binds to the
EGF receptor and potentiates radiotherapy

    MISSISSAUGA, ON, July 9 /CNW/ - YM BioSciences Inc. (AMEX: YMI, TSX: YM,
AIM: YMBA), an oncology company that identifies, develops and commercializes
differentiated products for patients worldwide, today announced that a study
presented by investigators from Kinki University School of Medicine and Kyoto
University at the 11th meeting of The Japanese Association for Molecular
Target Therapy of Cancer held on July 5-6, 2007 demonstrated the increased
radiosensitivity of human NSCLC cell lines in the presence of nimotuzumab both
in vitro and in vivo. The study also confirms previous observations that
nimotuzumab inhibits ligand-dependent EGF receptor downstream signaling.
Daiichi Sankyo Co., Ltd is the licensee for nimotuzumab in Japan.
    In addition, YM BioSciences announced that a paper on the structure of
nimotuzumab entitled 'Modeling the interaction between the anti-tumor antibody
h-R3 and its target, the epidermal growth factor receptor' was presented at
the 11th annual meeting of the SBNet (Structural Biology Network), held on
June 15-18, 2007 in Tallberg, Sweden. The paper demonstrated that nimotuzumab
specifically competes with cetuximab for binding to the EGF receptor. The
authors noted that, "According to our models, nimotuzumab inhibits the EGFr
signaling both by inhibiting the binding of EGF to domain III of EGFr and by a
conformational change of EGFr that is necessary to shape the EGF binding
site."
    "These two studies provide independent confirmation of earlier research
indicating that nimotuzumab directly binds to the EGF receptor," said Dr. Igor
Sherman, Director of Clinical Research at YM BioSciences. "The very rare
incidence, in patients treated with nimotuzumab, of the commonly seen
side-effects of EGFr-targeting therapy, such as rash and diarrhea, has raised
questions about whether nimotuzumab is truly interacting with the EGF
receptor. The data presented at SBNet provides further evidence that
nimotuzumab binds to the receptor, while the independent data from Kinki and
Kyoto demonstrated the synergistic effect of nimotuzumab and radiation on
cancer cells and inhibition of EGFr down-stream signaling in the presence of
nimotuzumab."
    "We conclude that nimotuzumab behaves no differently than the other
EGFr-targeting antibodies and that the limited and rare incidences of the
debilitating side-effects that are commonly seen with other antibodies and
small molecules targeting the tyrosine kinase pathway indicates that
nimotuzumab has the prospect of being "best-in-class" without compromised
efficacy," said David Allan, Chairman and CEO of YM BioSciences.

    About nimotuzumab

    Nimotuzumab is a humanized monoclonal antibody that targets the epidermal
growth factor receptor (EGFr). Nimotuzumab has been sub-licensed by CIMYM
BioSciences, a subsidiary of YM, to Daiichi Sankyo Co., Ltd for Japan and to
other companies advancing the drug including Oncoscience AG in Europe, Kuhnil
in South Korea and Innogene Kalbiotech in Southeast Asia. Nimotuzumab is
approved for sale in India and China as well as certain Latin American
countries for the treatment of head and neck cancers.
    YM BioSciences has previously announced its intention to initiate trials
with nimotuzumab in colorectal cancer and glioma, for which it has received No
Objection letters from Health Canada. YM also recently announced the receipt
of a No Objection Letter from Health Canada and a positive certificate of
inspection from a competent authority in the EU for the scaled-up
manufacturing of the drug at the Center of Molecular Immunology and also
announced an expected further doubling of manufacturing capacity at that
facility during 2007.

    About YM BioSciences

    YM BioSciences Inc. is an oncology company that identifies, develops and
commercializes differentiated products for patients worldwide. The Company has
two late-stage products: nimotuzumab, a humanized monoclonal antibody that
targets the epidermal growth factor receptor (EGFR) and is approved in several
countries for treatment of various types of head and neck cancer; and
AeroLEF(TM), a proprietary, inhaled-delivery composition of free and
liposome-encapsulated fentanyl in development for the treatment of moderate to
severe pain, including cancer pain.

    This press release may contain forward-looking statements, which reflect
the Company's current expectation regarding future events. These
forward-looking statements involve risks and uncertainties that may cause
actual results, events or developments to be materially different from any
future results, events or developments expressed or implied by such
forward-looking statements. Such factors include, 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. Certain of the assumptions
made in preparing forward-looking statements include but are not limited to
the following: that nimotuzumab will continue to demonstrate a competitive
safety profile in ongoing and future clinical trials; that AeroLEF(TM) will
continue to generate positive efficacy and safety data in future clinical
trials; and that YM and its various partners will complete their respective
clinical trials within the timelines communicated in this release. We
undertake no obligation to publicly update or revise any forward-looking
statements, whether as a result of new information, future events or
otherwise.

For further information: Enquiries: Thomas Fechtner, the Trout Group LLC,
Tel. [phone] x31, Fax [phone], Email:
tfechtner(at)troutgroup.com; James Smith, the Equicom Group Inc., Tel. (416)
815-0700 x 229, Fax [phone], Email: jsmith(at)equicomgroup.com
(YM. YMI YMBA)



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