Monday, December 07, 2009
Stimulation of the immune system can help to eliminate
a chronic infection with the human papillomavirus (HPV).
This has been demonstrated in research done by Centre for Medical Systems Biology (CMSB) partners at Leiden University Medical Center (LUMC) and the CMSB spin-off company
ISA Pharmaceuticals B.V.
They developed a therapeutic vaccine to treat vulvar intraepithelial neoplasia (VIN), a preliminary stage of cancer of the vulva which is caused by the HPV16 virus. The results were published in The New England Journal of Medicine.
The twenty women who participated in the research suffered from
a chronic, genital infection with Human Papillomavirus type
16 (HPV16). As a result, they had developed the condition vulvar intraepithelial neoplasia (VIN), a preliminary stage of cancer of
the vulva (vulvar cancer). VIN is characterised by itchiness, pain, swelling and wounds and is now generally treated with surgery.
During the study, the patients with VIN received four injections with parts of HPV16 proteins (peptides). Twelve months after the last injection, the condition had improved in 79 percent of the participants. All symptoms caused by HPV16 disappeared completely in nine women and the virus was no longer found in four out of the five women tested for the presence of the virus. Prof Kees Melief, Professor of Immunohaematology in the LUMC: ‘When people have been infected with HPV16 for prolonged periods of time, their immune system no longer responds adequately to the virus. By challenging the immune system with selected protein fragments (synthetic long peptides, SLPs) of the virus, the immune system can be activated once again.’
The treatment that has now been developed is called a therapeutic vaccine and is used to treat a disease. The SLP concept was developed by Prof Kees Melief and Dr Sjoerd van der Burg of the LUMC in cooperation with ISA Pharmaceuticals B.V. The clinical study was conducted in close cooperation with Prof. Gemma Kenter of the LUMC. The study that has now been published is the first step towards authorisation of the medicine, required to enable broad availability of the medicine. This process will take a number of years.
Whether the therapeutic SLP vaccine, as demonstrated in the VIN patients described above, is effective in patients with cervical cancer is not known. This is currently being investigated. HPV16 is the virus that causes approximately 50 percent of cases of cervical cancer, while it causes approximately 70-80 percent of cases of VIN. The preventative HPV vaccine against cervical cancer, which has been used to vaccinate girls since early 2009, is a different type of vaccine and does not have therapeutic activity in women already infected with HPV. That vaccine is used to prevent cervical cancer caused by HPV.
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