Recombinant adenovirus 26 vector avoids pre-existing immunity and is used in new HIV vaccine
Leiden, The Netherlands, 3 April 2008 - Dutch biotechnology company Crucell N.V. today announced that the novel recombinant adenovirus serotype 26 (rAd26) vector, which is jointly developed by Crucell and the Beth Israel Deaconess Medical Center (BIDMC), will be used in a phase I clinical study to test a new HIV vaccine. The rAd26 vector is specifically designed to avoid the pre-existing immunity to the more commonly used adenovirus serotype 5 (Ad5), which has recently shown limitations as an HIV vaccine vector.

The rAd26 vaccine is the first HIV vaccine candidate that emerges from the Integrated Preclinical/Clinical AIDS Vaccine Development (IPCAVD) program, which brings together researchers from academia and industry in an effort to accelerate the development of promising HIV/AIDS vaccines. Crucell, Harvard Medical School (HMS) and the BIDMC participate in this program, which is sponsored by the National Institutes of Health (NIH).

The phase I clinical study will be conducted at the Brigham and Women's Hospital (BWH) in Boston and will focus on assessing the safety and immunogenicity of the vaccine. The study will involve 48 healthy volunteers.

"The rAd26 vaccine vector has been selected for its particularly low seroprevalence in humans and for its potential immunogenicity and protective efficacy as was shown in preclinical studies", says Dan H. Barouch, MD, PhD, Associate Professor of Medicine at BIDMC and HMS and Principal Investigator in the IPCAVD program.

Jaap Goudsmit, Chief Scientific Officer at Crucell: "The rAd26 vector, as part of our AdVac® technology program, is designed to overcome the problem of pre-existing immunity in humans against the most commonly used recombinant vaccine vector, adenovirus serotype 5."

Antibodies to Ad5, a common cold virus, 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.

"The rAd26 vector does not regularly occur in the human population and antibodies to this vector are rare. The rAd26 vector therefore is efficacious in eliciting good T and B cell responses", Goudsmit continues. "We are excited about the first in man study of this newly developed vector, that could provide a solution to the issues that raised from previous HIV vaccine trials."

About PER.C6® technology
Crucell's PER.C6® technology is a cell line developed for the large-scale manufacture of biopharmaceutical products including vaccines. The production scale potential of the PER.C6® cell line has been demonstrated in an unprecedented successful bioreactor run of 20,000 litres. Compared to conventional production technologies, the strengths of the PER.C6® 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 the PER.C6® technology the biopharmaceutical production technology of choice for Crucell's current and potential pharmaceutical and biotechnology partners.

About AdVac® Technology
AdVac® 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® 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® technology is based on adenovirus vectors that do not regularly occur in the human population, such as Ad35. In contrast to the AdVac® vectors, 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® are produced using Crucell's PER.C6® production technology.

About Beth Israel Deaconess Medical Center (BIDMC)
BIDMC is a patient care, teaching and research affiliate of Harvard Medical School, and consistently ranks in the top four in National Institutes of Health funding among independent hospitals nationwide. BIDMC is clinically affiliated with the Joslin Diabetes Center and is a research partner of Dana-Farber/Harvard Cancer Care Center. For more information, visit www.bidmc.harvard.edu.

About Brigham and Women's Hospital (BWH)
BWH is a 747-bed non-profit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare, an integrated health care delivery network. BWH is committed to excellence in patient care with expertise in virtually every speciality of medicine and surgery. The BWH medical pre-eminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in quality improvement and patient safety initiatives and its dedication to educating and training the next generation of health care professionals. Through investigation and discovery conducted at its Biomedical Research Institute (BRI), BWH is an international leader in basic, clinical and translational research on human disease, involving more than 860 physician-investigators and renowned biomedical scientists and faculty supported by more than $416 M in funding. BWH is also home to major landmark epidemiologic population studies, including the Nurses' and Physicians' Health Studies and the Women's Health Initiative. For more information about BWH, please visit www.brighamandwomen's.org.