OTS-412 + hydroxyurea + atezolizumab

This is a **combination investigational therapy** being studied in **phase 1 clinical trials** for treatment-refractory solid tumors, particularly those resistant to standard and checkpoint inhibitor therapies. The regimen includes: - **OTS-412:** A recombinant oncolytic vaccinia virus engineered for tumor selectivity and with a controllable replication mechanism through mutant herpes simplex virus thymidine kinase (HSV-tk), allowing control of viral activity via ganciclovir if needed. OTS-412 is designed to promote tumor lysis, immune activation, and enhanced anti-tumor response[5][7]. - **Hydroxyurea:** A small molecule ribonucleotide reductase inhibitor cytotoxic agent that inhibits DNA synthesis and is often used to potentiate viral oncolytic therapy by creating a more permissive environment for viral replication. - **Atezolizumab:** A humanized IgG1 monoclonal antibody targeting programmed cell death ligand 1 (PD-L1), functioning as a checkpoint inhibitor to enhance anti-tumor immune responses[2][4]. Tecentriq is the marketed name for atezolizumab and is approved for multiple cancers, but its use in this combination is investigational. The main aim of the current clinical investigation is to determine the safety, immune response, optimal dosing, and anti-tumor activity of OTS-412 with hydroxyurea and atezolizumab in patients with solid tumors resistant to standard therapies, especially where checkpoint inhibitors alone have failed[3].

Other names

OTS-412 + hydroxyurea + atezolizumab