ISA101 consists of 13 synthetic long peptides (25-35 amino acids long) derived from the E6 and E7 oncogenic proteins of the HPV 16 virus. This strain is responsible for 50% of human cervical cancers and cervical intra-epithelial neoplasias and more than 85% of HPV-positive head and neck cancers, anal cancers and premalignant HPV-induced anal lesions (termed anal intra-epthelial neoplasia, or AIN). It is administered either subcutaneously or intradermally.
Although the majority of HPV16 infections causes no symptoms, are self-limited and cleared by a natural immune response, in some cases the virus becomes integrated into the DNA of cells causing persistent infections that may lead to precancerous lesions and cancer.
Two prophylactic vaccines against HPV infections are currently on the market. However, these vaccines are limited to preventing HPV infections and cannot cure established viral infections and associated lesions once HPV is incorporated into the genomic DNA.
With its ISA101 immunotherapeutic, ISA Pharmaceuticals is targeting the gap between preventive HPV vaccines and standard cancer treatments. The combined total market opportunity addressed by an immunotherapeutic against HPV16 amounts to a multi-billion dollar market annually.
ISA101 has completed a Phase II trial in vulvar intra-epithelial neoplasia, establishing clinical proof-of-concept. In cervical cancer, ISA101 has completed a Phase I/II trial and has entered into further clinical development in 2013. In addition, a Phase I/II trial in patients with anal intra-epithelial neoplasia (AIN) has started in 2013.