Morelli MP, et al. - Given that the efficacy of immune checkpoint inhibitor has been limited to small portion of colorectal cancer (CRC) patients whose tumors with mismatch repair (MMR) gene abnormalities, researchers evaluated whether the combination of Pexa-Vec oncolytic virus (PV) with immune checkpoint inhibition enhance antitumor immunity. Participants in the study were patients with microsatellite-stable and MSI-H mCRC refractory to PD-1 monotherapy. For this investigation, patients were treated with either Arm A treated with PV + Durvalumab or Arm B with PV + durvalumab and tremelimumab. On the basis of the data collected, it was concluded that Pexa-Vec in combination with durvalumab exhibited a favorable safety profile. Lymphopenia, chills, hypotension, papulopastular rashes, nausea and vomiting were the most frequent treatment-related adverse events.