Algeta Announces Radium-223 Chloride Met its Primary Endpoint of Significantly Improving Overall Survival in a Phase III Trial in Patients With Castration-Resistant Prostate Cancer That Has Spread to the Bone

OSLO, Norway, June 6, 2011 -

- Trial Stopped Based on Data Results from Pre-Planned Interim Analysis;
Patients in Placebo Arm Will Be Offered Treatment with Radium-223 Chloride

Algeta ASA (OSE: ALGETA) today announced that the Phase III
ALSYMPCA (radium-223 chloride in SYMptomatic Prostate CAncer) trial
evaluating the investigational compound radium-223 chloride, which is
exclusively licensed by Bayer, in patients with castration-resistant prostate
cancer (CRPC) and bone metastases met its primary endpoint by significantly
improving overall survival. Based on a recommendation from the Independent
Data Monitoring Committee (IDMC), following a pre-planned interim analysis,
the study will be stopped and patients on the placebo arm will be offered
treatment with radium-223 chloride. The overall survival result was
statistically significant (two-sided p-value =0.0022, HR = 0.699, the median
overall survival was 14.0 months for radium-223 chloride and 11.2 months for
placebo). The complete results from the study will be presented at an
upcoming scientific meeting.

The safety and tolerability of radium-223 chloride were
consistent with previous Phase I and Phase II trial outcomes and did not show
any new or unexpected changes in the safety profile of radium-223 chloride.
Common adverse events from the ALSYMPCA trial included diarrhea, neutropenia
and thrombocytopenia

Radium-223 chloride is an investigational agent and is not
approved by the U.S. Food and Drug Administration (FDA), the European
Medicines Agency (EMA) or other health authorities.

"We are pleased that radium-223 met its primary endpoint of
significantly improving overall survival in patients with CRPC and bone
metastases, and are hopeful about the potential of radium-223 chloride for
this patient population," said Andrew Kay, President and CEO of Algeta.

The filing strategy for radium-223 chloride based on the
IDMC's recommendation to stop this study, is being evaluated and patients in
the placebo arm will be offered treatment with radium-223 chloride.

Phase III Trial Design

The ALSYMPCA trial is a Phase III, randomized (2:1),
double-blind, multi-dose, placebo-controlled international study of
radium-223 plus current standard of care compared with placebo plus current
standard of care in patients with symptomatic
castration-resistant/hormone-refractory prostate cancer that has spread to
the bone. The primary endpoint of the study is overall survival. Secondary
endpoints include time to occurrence of skeletal related events (SRE),
changes and time to progression in prostate-specific antigen (PSA) tests and
alkaline phosphatase (ALP) tests, safety and impact on quality of life and
health economics. ALSYMPCA was initiated by Algeta ASA (Oslo, Norway) in June
2008. Enrollment in the trial was completed in January 2011 and 922 patients
were randomized.

About Radium-223 Chloride

Radium-223 chloride is an investigational pharmaceutical
containing an alpha-particle emitting nuclide in development for cancer
patients with bone metastases. In September 2009, Bayer signed an agreement
with Algeta for the development and commercialization of radium-223 chloride.
Under the terms of the agreement, Bayer will develop, apply for global health
authority approvals, and commercialize radium-223 chloride globally, while
Algeta retains an option for up to 50/50 co-promotion and profit-sharing in
the United States.

About CRPC and Bone Metastases

Prostate cancer is the most common cancer among men in
Northern European countries and the United States. In 2008, an estimated
903,000 men had prostate cancer and 250,000 died from the disease worldwide.

Castration-resistant prostate cancer (CRPC) was formerly known
as hormone-refractory prostate cancer (HRPC). Approximately 90 percent of men
with CRPC have radiological evidence of bone metastases. Once the cancer
cells settle in the bone, they interfere with bone strength, often leading to
bone pain, fracture and other complications that can significantly impair a
man's health. In fact, bone metastases are the main cause of disability and
death in patients with CRPC.

About Algeta

Algeta is a company focused on developing novel targeted
therapies for patients with cancer based on its alpha-pharmaceutical
platform.

Radium-223 chloride is being developed under a development and
commercialization agreement with Bayer Schering Pharma AG, and is in a global
phase III clinical trial (ALSYMPCA) to treat bone metastases resulting from
castration-resistant prostate cancer (CRPC). Radium-223 chloride is also
under investigation in phase IIa clinical trials as a potential new treatment
for bone metastases in endocrine-refractory breast cancer patients, and in a
phase I/IIa trial in combination with docetaxel chemotherapy in for bone
metastases CRPC patients.

Algeta is also exploring the potential of Targeted Thorium
Conjugates (TTCs), which are based on conjugating the alpha-emitter
thorium-227 to targeting molecules, as a basis of a future pipeline of
tumor-targeting alpha-pharmaceutical candidates.

The Company is headquartered in Oslo, Norway, and was founded
in 1997. Algeta listed on the Oslo Stock Exchange in March 2007 (Ticker:
ALGETA).

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. These 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.

Andrew Kay, CEO, +47-2300-7990 / +47-4840-1360 (mob), Gillies O'Bryan-Tear, CMO, +47-2300-7990 / +47-4840-1411 (mob), 0ystein Soug, CFO, +47-2300-7990 / +47-9065-6525 (mob), post at algeta.com International media enquiries: +44-207-638-9571, Mark Swallow/David Dible/Sita Shah mark.swallow at citigatedr.co.uk Citigate Dewe Rogerson US investor enquiries: +1-646-378-2928, Jessica Lloyd, jlloyd at troutgroup.com The Trout Group