TY - JOUR T1 - Simple and effective bacterial-based intratumoral cancer immunotherapy JF - Journal for ImmunoTherapy of Cancer JO - J Immunother Cancer DO - 10.1136/jitc-2021-002688 VL - 9 IS - 9 SP - e002688 AU - Christina S E Carroll AU - Erin R Andrew AU - Laeeq Malik AU - Kathryn F Elliott AU - Moira Brennan AU - James Meyer AU - Alexander Hintze AU - Andrew A Almonte AU - Cassandra Lappin AU - Philip MacPherson AU - Klaus-Martin Schulte AU - Jane E Dahlstrom AU - Rohit Tamhane AU - Teresa Neeman AU - Elizabeth W Herbert AU - Maurice Orange AU - Desmond Yip AU - Rachel Allavena AU - Aude M Fahrer Y1 - 2021/09/01 UR - http://jitc.bmj.com/content/9/9/e002688.abstract N2 - Background We describe intratumoral injection of a slow-release emulsion of killed mycobacteria (complete Freund’s adjuvant (CFA)) in three preclinical species and in human cancer patients.Methods Efficacy and safety were tested in mammary tumors in mice, in mastocytomas in mice and dogs, and in equine melanomas. In mice, survival, tumor growth, and tumor infiltration by six immune cell subsets (by flow cytometry) were investigated and analyzed using Cox proportional hazards, a random slopes model, and a full factorial model, respectively. Tumor growth and histology were investigated in dogs and horses, as well as survival and tumor immunohistochemistry in dogs. Tumor biopsies were taken from human cancer patients on day 5 (all patients) and day 28 (some patients) of treatment and analyzed by histology. CT scans are provided from one patient.Results Significantly extended survival was observed in mouse P815 and 4T1 tumor models. Complete tumor regressions were observed in all three non-human species (6/186 (3%) of mouse mastocytomas; 3/14 (21%) of canine mastocytomas and 2/11 (18%) of equine melanomas). Evidence of systemic immune responses (regression of non-injected metastases) was also observed. Analysis of immune cells infiltrating mastocytoma tumors in mice showed that early neutrophil infiltration was predictive of treatment benefit. Analysis of the site of mastocytoma regression in dogs weeks or months after treatment demonstrated increased B and T cell infiltrates. Thus, activation of the innate immune system alone may be sufficient for regression of some injected tumors, followed by activation of the acquired immune system which can mediate regression of non-injected metastases. Finally, we report on the use of CFA in 12 human cancer patients. Treatment was well tolerated. CT scans showing tumor regression in a patient with late-stage renal cancer are provided.Conclusion Our data demonstrate that intratumoral injection of CFA has major antitumor effects in a proportion of treated animals and is safe for use in human cancer patients. Further trials in human cancer patients are therefore warranted. Our novel treatment provides a simple and inexpensive cancer immunotherapy, immediately applicable to a wide range of solid tumors, and is suitable to patients in developing countries and advanced care settings.Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. We are happy to provide any further information. Please contact senior authors DY, MO, RA or AMF. ER -