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Arius Presents New Findings for Anti-cancer Antibody Programs atAACR

-ARIUS report new data and program updates on cancer stem cell targeting antibodies-   

TORONTO, April 15, 2008 /CNW/ - ARIUS Research Inc., (TSX: ARI), a  biotechnology company discovering and developing the next wave of antibody  therapeutics, today announced that it will be presenting new findings and  program updates related to its CD44, TROP-2, CD59, and CD9 antibody programs  at the American Association for Cancer Research (AACR) Annual Meeting held  from April 12-16, 2008 in San Diego, California.      

"Our five presentations at AACR shows the tremendous progress we made  over the last year with our lead programs. The new findings from our cancer  stem cell programs targeting CD44 and CD9 are of particular interest to the  scientific community as this is a promising new area of cancer research," said  Dr. David Young, President and CEO of ARIUS. "Specifically, we have been able  to demonstrate that our CD44 program has the potential for wide therapeutic  application in solid tumors, as well as blood cancers. Our cancer stem cell  antibody targeting CD9 differentially recognizes AML cancer stem cells  compared to normal stem cells. Furthermore, treatment with this antibody can  functionally reduce cancer stem cell self-renewal which has very important  therapeutic implications."   

CD44 Cancer Stem Cell Program   

Preclinical development of huARH460-16-2, a humanized antibody to the  CD44 cancer stem cell target. Abstract Number 3975. Experimental and Molecular  Therapeutics 32, Tuesday, April 15, 2008, 8:00 AM   

ARIUS' ARH460-16-2, a functional antibody that targets CD44, has a new  potential cancer indication for pancreatic cancer. The new findings show  anti-tumor effects in an established BxPC3 human pancreatic cancer model  (78.7% tumor growth inhibition at 2 mg/kg compared to control group). This  antibody has broad effects in solid tumors since it have been shown to be  effective in pancreatic, breast, liver, prostate cancer as well as AML. The  results of the toxicology study support the ongoing development of the of the  ARH460-16-2 antibody.   

Anti-CD44 antibody, ARH460-16-2, binds to human AML CD34+CD38- cancer  stem cells and demonstrates anti-tumor activity in an AML xenograft model.  Abstract Number 3976. Experimental and Molecular Therapeutics 32, Tuesday,  April 15, 2008, 8:00 AM   

This presentation highlights the effects of ARIUS' CD44 targeting  antibody, ARH460-16-2, on tumor cells from patients with various hematological  cancers, including acute myeloid leukemia (AML). This antibody shows very  potent anti-tumor effects in an AML tumor model (57% tumor growth inhibition  at a 10 mg/kg compared to control group). In addition the antibody lead to an  increase in the median survival to 62 days compared to 49 days in the control  group. These results demonstrate that the ARH460-16-2 antibody has the  potential for wide therapeutic application in hematological malignancies in  addition to its application to the therapy of solid tumors. 

ARIUS' ARH460-16-2 antibody is currently being manufactured for human  clinical studies. It targets CD44 which is a marker of cancer stem cells in a  broad range of solid cancers and AML. The first toxicology studies have been  completed for this antibody, and a U.S. FDA pre-IND meeting has been held  earlier in the year. This antibody is unique among CD44 antibodies in that it  has the capacity to cause tumor regression in established solid tumors. It can  directly act on cancer cells to induce apoptosis, or programmed cell death.  The antibody may be broadly applicable to solid tumors as well as hematologic  cancers.   

CD9 Cancer Stem Cell Program   

Anti-CD9 antibody, AR40A746.2.3, inhibits tumor growth in pancreatic and  breast cancer models and recognizes CD9 on CD34+CD38- leukemic cancer stem  cells. Abstract Number 3993. Experimental and Molecular Therapeutics 32,  Tuesday, April 15, 2008, 8:00 AM   

ARIUS has demonstrated that treatment with ARIUS' CD9 targeting antibody,  AR40A746.2.3, induced apoptosis in BxPC-3 pancreatic cancer cell as a  monotherapy. Moreover, apoptosis is achieved through inhibition of the AKT  pathway, commonly believed to be an important pathway for cancer cell  survival.      

New immunohistochemistry (IHC) studies using this antibody showed that  CD9 is expressed in a variety of human tumor samples, resulting in moderate to  high levels of staining in 61/82 (73.5%) of tumor cells from various organs  including pancreas, prostate, stomach and liver. The antibody demonstrated  potent anti-tumor efficacy in in vivo models of pancreatic, breast and AML  cancers and treatment led to a decrease in phosphorylation of several receptor  tyrosine kinases.      

CD9 is highly and differentially expressed in AML versus normal  CD34+CD38- stem cells. Experiments strongly suggest that ARIUS' CD9 targeting  antibody inhibits human AML outgrowth in pre-clinical studies. In secondary  transplantation experiments, treatment with ARIUS' CD9 targeting antibody  dramatically reduced the self-renewal capacity of AML cancer stem cells. CD9  is the first description of a marker that is differentially expressed on  cancer versus normal stem cells.   

Trop-2 Signal Transduction Program   

AR47A6.4.2, a naked monoclonal antibody targeting Trop-2, exhibits  anti-tumor efficacy in multiple human cancer models as a monotherapeutic agent  and demonstrates efficacy in combination therapy. Abstract Number 3990.  Experimental and Molecular Therapeutics 32, Tuesday, April 15, 2008, 8:00 AM   

ARIUS shows its Trop-2 targeting antibody, AR47A6.4.2, is involved in the  MAPK pathway. This antibody demonstrated potent anti-tumor efficacy in human  pancreatic, breast, colon and prostate cancer models. In combination with  Gemcitabine, this antibody also inhibited tumor growth by 93% in a human  pancreatic cancer model. ARIUS' Trop-2 targeting antibody is the only naked  therapeutic antibody targeting Trop-2.       A humanized version of this antibody has greater higher affinity than the  murine version and will be used in a pre-clinical toxicology study. A cell  line has been developed for the Trop-2 targeting antibody and it is currently  in manufacturing to generate material for Phase I clinical studies.   

CD59 Complement Inhibitor Program   

A monoclonal antibody targeting CD59 (AR36A36.11.1), enhances complement  activity and exhibits potent in vivo efficacy in multiple human cancer models.  Abstract Number 3995. Experimental and Molecular Therapeutics 32, Tuesday,  April 15, 2008, 8:00 AM   

ARIUS has expanded its expression profiling and has characterized the  affinity for its CD59 targeting antibody, AR36A36.11.1. This antibody has  demonstrated significant in vivo anti-tumor activity towards a broad range of  high incidence cancers and is highly potent at low dose concentrations in  tumor xenografts, comparing favorably to standard of care in breast and  prostate cancer.      

The effectiveness of this very potent antibody may be attributed to its  ability to block CD59 function, representing a novel approach to cancer  treatment. Currently, there are no other reported naked therapeutic antibodies  targeting CD59 in clinical development.      

A humanized version of ARIUS' CD59 targeting antibody demonstrated  equivalent affinity and potency to the murine version, and a CHO cell line  producing humanized AR36A36.11.1 has been generated to manufacture material  for future clinical studies.   

About ARIUS   

ARIUS is a biotechnology company discovering and developing the next wave  of antibody therapeutics. Established in 1999, ARIUS has built a proprietary  technology platform, FunctionFIRST(TM), that rapidly identifies and selects  antibodies based on their functional ability to affect disease. This antibody  generation engine has enabled ARIUS to assemble a portfolio of more than 500  antibody candidates. In addition to the antibodies it is developing in-house,  ARIUS has ongoing partnerships with key biotechnology and drug development  companies. ARIUS is listed on the TSX under the symbol "ARI".

Forward-Looking Statements   

Certain statements in this news release constitute "forward-looking  statements" within the meaning of the Private Securities Litigation Reform Act  of 1995, which involve known and unknown risks, uncertainties and other  factors that may cause our actual results to be materially different from any  future results, performance or achievements expressed or implied by such  statements. Forward-looking statements in this release include, but are not  limited to, ARIUS successfully advancing its new product programs as well as  licensing opportunities. These statements are only predictions and actual  events or results may differ materially. Factors that could cause such actual  events or results expressed or implied by such forward-looking statements to  differ materially from any future results expressed or implied by such  statements include, but are not limited to: early stage of development;  technology and product development; dependence on and management of current  and future corporate collaborations; future capital needs; uncertainty of  additional funding; no assurance of market acceptance; dependence on  proprietary technology and uncertainty of patent protection; intense  competition; manufacturing and market uncertainties; and government  regulation. These and other factors are described in detail in ARIUS' Annual  Report, forthcoming news releases and other filings with Canadian securities  regulatory authorities available at Forward-looking statements  are based on our current expectations and ARIUS is not obligated to update  such information to reflect later events or developments.

Posted: April 2008