Pentrys Vaccine

The Pentrys™ vaccine is a unique treatment applicable to up to 50% of all cancers. It targets one of the most common defects in cancer cells – a mutated p53 gene. Pentrys™ could be an effective treatment for patients following removal of a tumour and could also be used in cases where early diagnosis is possible.

To be able to take advantage of the distinction that is made between cancer cells and normal cells by the mutated p53 protein, AustCancer has developed a technology known as an anti-idiotypic vaccine against mutated p53. An anti-idiotypic vaccine is designed to trick the body into seeing the cancerous cells as being foreign. This induces an immune response and those cells displaying mutant p53 protein on their surface are killed by the immune system. Since the mutated p53 protein is only displayed on tumour cells, only tumour cells will be killed by the immune system. Normal cells will be unaffected.

Pentrys™ vaccine technology is based on the synthesis of human antibodies to the mutated p53 tumour suppressor gene. The antibodies that these are derived from were isolated from the lymph nodes of individuals who had shown a strong natural immune response to their cancer and recovered unexpectedly.

The antibodies were developed after seven years of research by a St Vincent’s Hospital, Sydney team led by Associate Professor Robyn Ward. The antibodies are unique, as they are the only entirely human p53 antibodies currently available in the world.

The Pentrys™ vaccine is a mixture of nine peptides (small proteins), which are derived from these antibodies. Pentrys™ has some distinct competitive advantages over other cancer vaccine approaches. Firstly, it is a broad-spectrum vaccine which is potentially applicable to the 50% of all cancers which have mutations in their p53. gene. This includes common cancers such as breast, bowel, prostate and lung. Most cancer treatments are only for specific cancer types and are unlikely to be effective against such a broad range of cancers. The second major point of difference is that many cancer vaccines currently in development involve removing a patient’s own cells and engineering them to trick that particular person’s immune system into attacking the cancerous cells. Pentrys™ is not patient specific and does not involve the use of cells. The same vaccine can be used in all patients. This decreases the time taken to prepare the treatment and will also make it more cost-effective and less complex to obtain regulatory approvals than competing technologies. Being a broad-spectrum vaccine applicable to up to 50% of all cancers in all patients Pentrys™ has the potential to become a blockbuster therapy.