TLR agonists can be used in combination with RT to enhance the antitumor immune response. This combination therapy was more efficient than either treatment alone and provided protection against subsequent tumor rechallenges.
Brody et al treated 15 patients with metastatic low-grade B cell lymphomas with low doses of radiation (2 x 2 Gy in 2 consecutive days). They combined the RT with intratumoral injections of CpG, into the same irradiated site, before the first dose of radiation, after the second dose and then weekly for 8 weeks . This in situ vaccination maneuver was well tolerated with only grades 1 to 2 local or systemic reactions and no treatment-limiting adverse events were observed. By doing so, they obtained