Immune checkpoint inhibitor (ICI) treatment has produced striking results in patients with colorectal cancer (CRC) of the subtype deficient mismatch repair (dMMR), with brief preoperative ICI treatment resulting in complete shrinkage of the tumor. However, dMMR CRC constitute 10% of all CRC diagnoses. The majority of patients have proficient MMR (pMMR) tumors, with limited effect of ICIs. The key difference between dMMR and pMMR tumors is the infiltration of cytotoxic T-cells. dMMR tumors have increased infiltration and thus increased efficacy from ICI treatment. In CSS, we have conducted a proof of concept study where we applied an intratumoral (IT) unaltered flu vaccine in ten patients with non-metastatic pMMR CRC. The intervention increased infiltration of cytotoxic T-cells and the immune checkpoint PD-L1, suggesting that IT flu vaccine primes pMMR tumors to ICI treatment (publication in preparation, not peer-reviewed data). We plan to test the combination of IT flu vaccine and the ICI treatment pembrolizumab in patients with non-metastatic pMMR CRC in a new trial. The aim with the study is to induce pathological response.
See https://www.neye.dk/blog/neye-fonden/ for more information about NEYE-fonden.
If you would like to hear more about the study, contact Ismail Gögenur at firstname.lastname@example.org.