Previously, we completed four trials combining local radiotherapy (a standard of care for these diseases) with intratumoral administration of TLR agonists - an approach we refer to as 'in situ vaccination' for patients with previously untreated or relapsed/refractory low-grade lymphoma. We demonstrated safety, induction of anti-tumor CD8 T cell responses and partial and complete remissions of patients' non-irradiated sites of disease.1, 2 The most recent trials compared previously untreated versus relapsed/refractory patients receiving the same therapy and observed superior responses in the former group, presumably due to immunosuppressive effects of prior treatments in the latter group. The in situ vaccine is premised on pre-clinical data showing this approach to be superior to systemic TLR agonist delivery3 and our clinical results reproduce this finding; in situ vaccination yields superior response rates as compared to trials of systemic TLR agonist therapy for lymphoma.4