Breakthrough study reports complete and partial remissions following vaccination
A new vaccine designed to stimulate an immune response against a cancer-causing human papillomavirus (HPV-16) can eliminate chronic infection by the virus and may cause regression of precancerous genital lesions in women who receive the vaccine.
According to a report published in the November 5 issue of the New England Journal of Medicine (2009;361:1838-47), the vaccine successfully induced HPV-specific immune responses in 100% of patients with advanced vulvar intraepithelial neoplasia (VIN3), a life-threatening disease that in the majority of cases results from HPV infection and for which there is as yet no satisfactory standard therapy.
Among the women who participated in the study, the majority (79%) experienced measurable regression of their VIN3 lesions within 1 year of vaccination. Nine of the women (47%) experienced complete disappearance of lesions and were still symptom-free two years following vaccination. The virus was undetectable in four of five women whose disease had regressed completely after the first year.
According to researchers who conducted the phase II study at the Leiden University Medical Center in Leiden, The Netherlands, spontaneous regression of HPV-16 positive VIN3 lesions is very rare, occurring in less than 1.5% of patients. The induction of HPV-specific T-cell immune responses following vaccination, and the researchersÃ¢â‚¬â„¢ observation that stronger vaccine-induced immune responses correlated with better clinical outcome indicate that the vaccine is the most likely cause of the high response rate among the patients treated in the study.
Unlike recently approved vaccines that prevent against infection by HPV, such as MerckÃ¢â‚¬â„¢s GardasilÃ‚Â® and GlaxoSmithKlineÃ¢â‚¬â„¢s CervarixÃ‚Â®, this is a therapeutic HPV vaccine for people who have already been exposed to HPV and who are unable to clear the virus on their own and are at high risk of developing HPV-related cancer.
The vaccine is composed of HPV synthetic long peptides (SLPÃ‚Â®), a proprietary technology developed by Dr. Cornelis Melief and others at Leiden University in The Netherlands in partnership with ISA Pharmaceuticals. In recognition of this and his other important contributions to the development of immune-based therapies for cancer, Dr. Melief received in June of this year the 2009 William B. Coley Award for Distinguished Research in Tumor Immunology from the Cancer Research Institute (CRI), a nonprofit organization based in the United States dedicated exclusively to harnessing the power of the immune system to treat, control, and prevent cancer.
To accelerate the testing and refinement of synthetic long peptides in the treatment of cancers that are not of viral origin, the Cancer Research Institute awarded Dr. Melief a grant of $300,000 for the establishment of a Good Manufacturing Practice (GMP) facility at Leiden University. The facility will produce clinic-grade synthetic long peptides for use in clinical trials within the Cancer Vaccine Collaborative (CVC), a joint program of the Cancer Research Institute and the Ludwig Institute for Cancer Research Ltd (LICR) in 2009.
The CVC is a global network of academic clinical trial sites and immune monitoring laboratories that is carrying out a coordinated program of early stage trials of therapeutic cancer vaccines. To date, the CVC has conducted more than 40 trials of various combinations of therapeutic vaccines targeting highly immunogenic cancer antigens, chiefly the NY-ESO-1 antigen. NY-ESO-1 is a prototypic member of the cancer-testis (CT) family of antigens, which are expressed in cancer but not normal adult tissue. In a recent publication, the National Cancer Institute prioritized this antigen among the top 10 most promising cancer immunotherapy targets available. NY-ESO-1 has been the central focus of CVC and other CRI or LICR sponsored studies for more than a decade.
Dr. Melief will supply CVC investigators with synthetic long peptides derived from XAGE antigens, which have properties similar to other CT antigens including NY-ESO-1. XAGE antigens are expressed in a number of cancers, particularly adenocarcinoma of the lung. CVC investigators will test the efficacy of delivering XAGE in the form of synthetic long peptide as compared to vaccines that deliver XAGE in the form of whole protein or DNA.
Upon completion of the GMP upgrade to Leiden UniversityÃ¢â‚¬â„¢s synthetic long peptide production facility, it will be the second of two academically funded and operated bioproduction facilities within the CVC network. The first, at Cornell University in Ithaca, New York, recently completed production of clinic-grade recombinant NY-ESO-1 protein for CVC trials in melanoma and ovarian cancer, and is now producing clinic grade Melan-A/MART-1 protein for CVC clinical trials.
About vulva epithelial neoplasia
An epithelial neoplasia occurs when cells lining the outer layers of the body (for instance the skin and inside the mouth, intestines and the genitalia) start dividing and growing in an unusual way. An epithelial neoplasia can manifest itself as a wart or a lump, and in some cases it can develop into cancer, if left untreated. A majority of epithelial neoplasias of the vulva (the outer parts of the female genitalia) are caused by an infection of human papilloma virus type 16. Symptoms of the disease include discomfort, itching, irritation, pain and local bleeding. Epithelial neoplasia of the vulva is chronically debilitating and life-threatening due to the associated symptoms and the high risk of developing invasive cancer. (Source: ISA Pharmaceuticals)
About the CRI/LICR Cancer Vaccine Collaborative
The Cancer Vaccine Collaborative is a partnership between two not-for-profit institutions, the Cancer Research Institute (CRI) and the Ludwig Institute for Cancer Research (LICR). Each of these institutions has a long and distinguished history in the field of cancer immunology and each is committed to translating laboratory discoveries in this field into therapeutic cancer vaccines. Begun in 2001, the CRI/LICR Cancer Vaccine Collaborative supports and coordinates a network of early phase cancer vaccine trials at nineteen hospitals and medical centers around the world. Driven by a scientific agenda, these parallel, single-variable trials use defined antigens, standard treatment protocols, uniform monitoring methodologies, and centralized data collection to provide comparable results that are teaching us how to effectively immunize against cancer.