A team of medical and veterinary researchers at the University of California – Davis examined the efficacy and immunologic effects of a novel triple therapy consisting of local radiotherapy, intratumoral CpG oligodeoxynucleotides (CpG ODN), and systemic indolamine-2,3-dioxygenase (IDO) blockade in mouse models and dog clinical trials. The addition of IDO blockage to radiotherapy + CpG decreased IDO activity, reduced tumor growth and reduced immunosuppressive factors.


  • Arta Monjazeb, MD, PhD
  • Michael Kent, DVM, PhD 

Three key benefits to the findings

  • Results suggested that IDO maintains immune suppression in tumors after therapy and IDO blockade promotes a local anti-tumor immune response with systemic consequences
  • Demonstrated that combinatorial strategies designed to minimize overlapping toxicity can be safe and effective
  • Results provided strong rationale for clinical translation of the triple-therapy strategy to substantially improve the already documented efficacy of radiotherapy + CpG