Highest CD8 immune responses ever in a TB vaccine study

Preliminary data show both critical arms of the cellular immune system, CD4 and CD8 immune T-cells were induced and that in those participants who responded, CD8 immune responses are considerably higher than has ever previously been seen in a TB vaccine study.

The trial of AERAS-402/Crucell Ad35, which began in May 2007, is being conducted as a double-blind, randomized, placebo-controlled dose escalation study in four groups of healthy adults vaccinated at birth with BCG (Bacille Calmette-Guerin) vaccine. A total of 40 healthy adult volunteers are enrolled.

"While preliminary, these results are promising. We are pleased that Crucell's technologies are playing a key role in the search and development of a much-needed TB vaccine," said Dr. Jaap Goudsmit, Chief Scientific Officer at Crucell. "We highly value the collaboration with Aeras and SATVI on this important mission."

Third key clinical phase I study in progress

Aeras and Crucell began jointly developing this vaccine candidate in 2004 using Crucell's AdVac(R) vaccine technology and PER.C6(R) manufacturing technology. A first Phase I clinical trial launched in October 2006 in Kansas, USA indicated that the vaccine candidate is safe in healthy adults in the US. The results of a second study, launched in May 2007, are presented in Atlanta at the "TB Vaccines for the World" conference. A third phase I study in healthy adults in St. Louis, Missouri, USA was launched in December 2007 and focuses on the immunogenicity and safety of two AERAS-402/Crucell Ad35 boost doses administered at three to six month intervals after BCG priming in healthy adults.

"The world urgently needs a new TB vaccine, and although we are still in the early stages of clinical trials, the preliminary data of this second phase I study are promising," said Dr. Jerald C. Sadoff, President and CEO of Aeras. "Aeras is delighted to be working with the excellent researchers at Crucell and SATVI. We are grateful to the Bill & Melinda Gates Foundation, the Netherlands Ministry of Foreign Affairs, and our other donors for their financial support of this trial and our vaccine development efforts."

This trial was conducted in the Boland-Overberg region of Western Cape Province in South Africa, which has one of the world's highest TB burdens.

"SATVI is proud to be playing such an important role in the global effort to develop new vaccines to combat TB, which are needed in South Africa and worldwide," said Dr. Gregory Hussey, Director of SATVI and Principal Investigator for the trial. "By conducting this trial, we have advanced the development of a new TB vaccine, expanded scientific capacity, and built awareness of the need for new TB vaccines."

About Tuberculosis

Tuberculosis is the world's second deadliest infectious disease, with over 9 million new cases diagnosed in 2006. According to the World Health Organization (WHO), an estimated 1.7 million people died from TB in 2006. One third of the world's population has been infected with the TB bacillus and current treatment takes 6-9 months. The current TB vaccine Bacille Calmette-Guerin (BCG), developed over 85 years ago, reduces the risk of severe forms of TB in early childhood, but is not very effective in preventing pulmonary TB in adolescents and adults - the populations with the highest rates of TB disease. TB is changing and evolving, making new vaccines more crucial to controlling the pandemic. Tuberculosis is now the leading cause of death for people living with HIV/AIDS, particularly in Africa. Multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) are hampering treatment and control efforts.

About AdVac(R) technology and Ad35

AdVac(R) technology is a vaccine technology developed by Crucell and is considered to play an important role in the fight against emerging and re-emerging infectious diseases, and in biodefense. The technology supports the practice of inserting genetic material from the disease-causing virus or parasite into a "vehicle" called a vector, which then delivers the immunogenic material directly to the immune system. Most vectors are based on an adenovirus, such as the virus that causes the common cold. The AdVac(R) technology is specifically designed to manage the problem of pre-existing immunity in humans against the most commonly used recombinant vaccine vector, adenovirus serotype 5 (Ad5), without compromising large-scale production capabilities or the immunogenic properties of Ad5. AdVac(R) technology is based on adenoviruses that do not regularly occur in the human population, such as Ad35. In contrast to, for instance, Ad35 antibodies, antibodies to Ad5 are widespread among people of all ages and are known to lower the immune response to Ad5-based vaccines, thereby impairing the efficacy of these vaccines. All vaccine candidates based on AdVac(R) are produced using Crucell's PER.C6(R) production technology.

About PER.C6(R) technology

Crucell's PER.C6(R) technology is a cell line developed for the large-scale manufacture of biopharmaceutical products including vaccines. The production scale potential of the PER.C6(R) cell line has been demonstrated in an unprecedented successful bioreactor run of 20,000 liters. Compared to conventional production technologies, the strengths of the PER.C6(R) technology lie in its excellent safety profile, scalability and productivity under serum-free culture conditions. These characteristics, combined with its ability to support the growth of both human and animal viruses, make PER.C6(R) technology the biopharmaceutical production technology of choice for Crucell's current and potential pharmaceutical and biotechnology partners.

About Aeras

The Aeras Global TB Vaccine Foundation (http://www.aeras.org/) is a non-profit organization working as a Product Development Partnership to develop new tuberculosis vaccines and ensure that they are distributed to all who need them around the world. Aeras is funded by the Bill & Melinda Gates Foundation, the Netherlands Ministry of Foreign Affairs, the Danish International Development Agency, the Research Council of Norway and the U.S. Centers for Disease Control and Prevention. Aeras, with over 110 employees, is based in Rockville, Maryland, where it operates a state-of-the-art manufacturing and laboratory facility.

About Crucell

Crucell N.V. (Euronext, Nasdaq: CRXL; Swiss: CRX.SW) is a biotechnology company focused on research, development and worldwide marketing of vaccines and antibodies that prevent and treat infectious diseases. Its vaccines are sold in public and private markets worldwide. Crucell's core portfolio includes a vaccine against hepatitis B, a fully-liquid vaccine against five important childhood diseases, and a virosome-adjuvanted vaccine against influenza. Crucell also markets travel vaccines, such as the only oral anti-typhoid vaccine, an oral cholera vaccine and the only aluminum-free hepatitis A vaccine on the market. The Company has a broad development pipeline, with several Crucell products based on its unique PER.C6(R) production technology. The Company licenses this and other technologies to the biopharmaceutical industry. Important partners and licensees include DSM Biologics, sanofi aventis, GSK and Merck & Co. Crucell is headquartered in Leiden (the Netherlands), with subsidiaries in Switzerland, Spain, Italy, Sweden, Korea and the US. The Company employs over a 1000 people. For more information, please visit http://www.crucell.com/.

About SATVI

The South African Tuberculosis Vaccine Initiative is located in the Institute of Infectious Disease and Molecular Medicine at the University of Cape Town (UCT). Since 1999, with funding largely from the Aeras Global TB Vaccine Foundation, SATVI has developed the capacity to conduct registration standard vaccine trials at a site in Worcester, some 110km outside Cape Town, where rates of tuberculosis are amongst the highest in the world. SATVI has a state of the art immunology laboratory located at UCT, where the complex assays needed for TB vaccine studies can be performed. In the last 6 years SATVI has conducted a number of very large field trials and epidemiological cohort studies of the type which will be necessary to test the efficacy of new tuberculosis vaccines, involving thousands or tens of thousands of participants, as well as a number of smaller phase one and two trials of new TB vaccines. In addition, SATVI conducts cutting edge basic science research aimed at better understanding the human immune response to tuberculosis and to tuberculosis vaccines. For more information, please visit http://www.satvi.uct.ac.za/.

Forward-looking statements

This press release contains forward-looking statements that involve inherent risks and uncertainties. We have identified certain important factors that may cause actual results to differ materially from those contained in such forward-looking statements. For information relating to these factors please refer to our Form 20-F, as filed with the U.S. Securities and Exchange Commission on June 13, 2007, and the section entitled "Risk Factors." The Company prepares its financial statements under generally accepted accounting principles in the United States (US GAAP) and Europe (IFRS).

CONTACT: Barbara Mulder, +1-31

Source: Aeras Global TB Vaccine Foundation

www.aegis.org