Researchers have recruited the first vaccine candidates to one of two new prevention trials that seek to immunize high-risk individuals against Lynch syndrome, the most common cause of hereditary colorectal cancer. Individuals who inherit the condition have an estimated lifetime risk as high as 80% for developing one of these malignancies, as well as an above-average risk for cancers arising in other organs, often at an early age, and regardless of race or gender.

The Nous-209 vaccine—named partially for the number of neoantigens or “new” antigens it contains, and in part for the Switzerland-based company (Nouscom) that developed it—employs what investigators call “a brute force” approach. The vaccine contains 209 bits and pieces of cancer-specific neoantigens expressed only in premalignant or malignant tissues of individuals with Lynch syndrome that researchers hope will stimulate a robust immune-system attack that stops cancer progression at its origin.

In comparison, the Tri-Ad5 vaccines, developed through the National Cancer Institute’s (NCI’s) intramural program, rely on three tumor-associated antigens that are overexpressed in cancer cells, but are also found to a lesser degree in healthy tissues. Because early studies suggested that the approach with only the MUC-1 antigen showed promise, investigators added two other antigens (CEA and brachyury) in the Tri-Ad5 vaccines, which will be combined with an Interleukin-15 (IL-15) “superagonist,” a vaccine stimulant, to increase the vaccine’s potential for destroying premalignant lesions or early tumors.

 “Right now, we are focused on helping high-risk populations, and they, in turn, are teaching us how to develop better cancer preventive vaccines for the future.”

https://prevention.cancer.gov/news-and-events/blog/trials-test-vaccines?fbclid=IwAR2tAZ9dnoQG5wV9sqQG7IkCS-xn0c7er5BbdKrEdlhX3OcCnKDYCyU3Gko#.Y-UkYVtB9fY.facebook