Media release

From: Springer Nature

1.  Cancer: Vaccine shows promise in patients with pancreatic or colorectal cancer

A type of cancer immunotherapy is found to help prolong long-term recurrence-free survival in some patients with pancreatic or colorectal cancer, according to the results of a phase 1 clinical trial, published in Nature Medicine. The authors suggest that this peptide-containing vaccine, called ELI-002 2P, which is not personalised and is manufactured in bulk and off-the shelf, could help to lengthen survival in pancreatic and colorectal cancer patients.
The relapse rates for pancreatic and colorectal cancer are known to be high, even after surgery and chemotherapy, especially when small traces of cancer remain in the body. Cancer vaccines are designed to stimulate T cells, a type of immune cell, to specifically recognise and kill cancer cells and can be personalised to the patient’s individual tumour proteins. Pancreatic and colorectal cancers frequently carry mutations in the gene KRAS, which plays a key role in their growth, and are therefore an ideal target for immunotherapies, such as cancer vaccines. Although mutant KRAS proteins can be targeted by inhibitors and T cell therapy, an off-the shelf vaccine-based treatment approach could lead to the development of durable and protective immune responses. However, traditional vaccines are not optimised and have not been successful for delivery to the lymph nodes, the centres of immune response development.

Zev Wainberg and colleagues conducted a phase 1 trial involving 25 patients (20 with pancreatic cancer and 5 with colorectal cancer) who had finished standard treatment but still showed residual signs of cancer in their blood. The patients received the ELI-002 2P vaccine immunotherapy, designed to help the immune system recognise and attack KRAS-mutant cancer cells by targeting mutant KRAS peptides to the lymph nodes. After an average follow-up time of almost 20 months, 68% of the participants had developed strong T cell responses specific to mutant KRAS tumour proteins. More specifically, these patients with the strongest T cell responses lived longer and stayed cancer free for longer than those with weaker responses.
In the patients with pancreatic cancer who received the vaccine, the average overall survival length was almost 29 months after vaccination, and the average recurrence-free survival was more than 15 months, exceeding historical control data. The researchers also found that in a subset of patients, the vaccine ELI-002 2P helped the immune system to recognise not just the targeted mutant KRAS proteins but also other mutant KRAS proteins unique to each patient’s tumour and not included in the vaccine. This suggests early signs that ELI-002 2P can elicit T-cells responses to personalised tumor antigens of the patients.

Wainberg and co-authors suggest that ELI-002 2P helps train immune cells to recognise and attack pancreatic and colorectal cancers more effectively. The authors note that the vaccine is currently undergoing further testing in a phase 2 randomised trial.