New research highlights potential of novel alpha-pharmaceutical in targeting and killing breast cancer cells

Oslo, Norway - Algeta ASA (OSE: ALGETA), the cancer therapeutics company, announces results of new research demonstrating that the alpha particle emitter thorium-227 (227Th) linked to the monoclonal antibody trastuzumab (Herceptin) selectively targets and kills breast cancer cells.

The research, which was conducted by a team of scientists from the Norwegian Radium Hospital led by Dr. Jostein Dahle in collaboration with Algeta, was presented at the 56th annual Society for Nuclear Medicine 2009 meeting (Toronto, Canada; 13-17 June).

This is the first time that the targeted cancer cell-killing effect of 227Th-trastuzumab has been presented and suggests that further studies be conducted with this alpha-pharmaceutical as a novel treatment for breast cancer. Trastuzumab, known commercially as Herceptin and marketed by Roche/Genentech, targets tumor cells presenting the HER-2 receptor on their cell surface, and tumors in approximately 25% of breast cancer patients carry this marker.

The presentations given at SNM meeting pointed to three key findings of the effects of 227Th-trastuzumab on breast cancer cells expressing HER-2:

Target specificity: 227Th-trastuzumab selectively targeted and bound HER-2 presenting tumor cells in vitro and in mice with HER-2 positive tumors

Tumor cell-killing effect: 227Th-trastuzumab exerted a measurable and dose-dependent therapeutic effect by killing HER-2 positive breast cancer cells to which it was bound and had a significant effect on tumor growth at low doses, and

Indication of safety: Blood toxicity of 227Th-trastuzumab, determined from measuring white blood cell counts in the mouse models, was modest and temporary. This is believed to be a result of the targeted and localized mode of action of 227Th-trastuzumab.

Thorium-227, is an element (radionuclide) that emits high-energy alpha particles. Such elements are of considerable interest in the treatment of cancer as they are potent at killing tumor cells but have a highly localized effect. By linking thorium-227 to tumor-targeting molecules such as monoclonal antibodies, Algeta has the potential to create a pipeline of new generation alpha-pharmaceuticals with the potential to specifically seek and destroy cancers while minimizing damage to surrounding healthy tissues.

This technology was highlighted as one of the more exciting new developments at the conference by Michael J. Welch, professor of radiology at the Washington University School of Medicine’s Mallinckrodt Institute of Radiology in St. Louis (MI), and a leading US radiological scientist, in the “Basic Science Summary Session - Radiopharmaceutical Sciences. In this session, Prof. Welch noted that linking thorium-227 to monoclonal antibodies had generated ”impressive results from this new alpha radionuclide"

Thomas Ramdahl, EVP and Chief Technology Officer at Algeta, said, “The huge potential of alpha-pharmaceuticals has already been shown with Alpharadin; Algeta’s phase III therapeutic for bone metastases. This new work confirms that, by creating novel molecular entities based on a biologic coupled to thorium-227, we may be able to extend the benefits of alpha-pharmaceuticals to a whole new set of clinical targets among soft tissue tumours. The present studies are still early stage but show the significant promise of Algeta’s product pipeline.”

For further details of the presentations, please contact post@algeta.com

About Algeta
Algeta ASA is a cancer therapeutics company built on world-leading, proprietary technology. Algeta is developing a new generation of targeted cancer therapeutics (alpha-pharmaceuticals) that harness the unique characteristics of alpha particle emitters and are potent, well-tolerated and convenient to use.

Algeta’s lead alpha-pharmaceutical candidate, Alpharadin (based on radium-223), has blockbuster potential for treating bone metastases arising from multiple major cancer types, owing to its bone-targeting nature, potent efficacy (therapeutic and palliative) and benign, placebo-like safety profile. Development of Alpharadin is most advanced targeting bone metastases resulting from hormone-refractory prostate cancer (HRPC), and it entered an international phase III clinical trial (ALSYMPCA) in mid-2008 based on compelling clinical results from a comprehensive phase II program.

Algeta’s strategy is to launch Alpharadin as a first or second line treatment for cancer patients with bone metastases either alone or in combination with current standard of care therapies, thereby maximizing its commercial potential.

Algeta is also developing other technologies for delivering alpha-pharmaceuticals. These include microparticles, liposomes, and methods to enhance the potency of therapeutic antibodies and other tumor-targeting molecules by linking them to the alpha particle emitter thorium-227. The Company is headquartered in Oslo, Norway, and was founded in 1997.

Algeta listed on the Oslo Stock Exchange in March 2007 (Ticker: ALGETA).

Alpharadin and Algeta are trademarks of Algeta ASA.

Forward-looking Statement
This news release contains forward-looking statements and forecasts based on uncertainty, since they relate to events and depend on circumstances that will occur in the future and which, by their nature, will have an impact on results of operations and the financial condition of Algeta. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied by these forward-looking statements. Theses factors include, among other things, risks associated with technological development, the risk that research & development will not yield new products that achieve commercial success, the impact of competition, the ability to close viable and profitable business deals, the risk of non-approval of patents not yet granted and difficulties of obtaining relevant governmental approvals for new products.