In Moderna’s cancer vaccine, mRNA (messenger RNA) is produced in a laboratory by utilizing mutations in the patient’s melanoma cell DNA. The RNA, or production instructions, is delivered in the vaccine, and the patient’s own immune system directs T cells to attack the right target—the cancer cells. It is similar to how our cells were taught to attack the coronavirus spike protein with the COVID-19 vaccine.
The question remains whether bexmarilimab can modify the microenvironment so that those educated T cells can act on cancer cells more effectively than with Merck’s pembro (pembrolizumab) alone, as given in that study. Another question is whether “bex” could play a role in the presentation of vaccine-generated antigens in macrophages, given that dendritic cells effectively perform this task and the vaccine now enhances the generation of the antigen response.
The patients in that study were slightly “easier” than those in the BLAZE trial because their visible melanoma had been surgically removed, though sometimes those cells remain hidden somewhere. The attempt is to vaccinate away that small amount. In the BLAZE trial, nivolumab, which has a mechanism of action similar to pembro, is used. The patients have already undergone prior pembro/nivo treatment, the disease has recurred, and they must have measurable disease.
The market values of Moderna and Merck jumped by about 40 billion USD yesterday, which was perhaps partly due to shorts, but it shows that cancer immunology is a hot topic.