A review of immune therapy in cancer and a question: can thermal therapy increase tumor response?

Immune therapy is a successful cancer treatment coming into its own. This is because checkpoint molecules, adoptive specific lymphocyte transfer and chimeric antigen T-cell (CAR-T) therapy are able to induce more durable responses in an increasing number of malignancies compared to chemotherapy. In addition, immune therapies are able to treat bulky disease, whereas standard cytotoxic therapies cannot treat large tumour burdens. Checkpoint inhibitor monoclonal antibodies are becoming widely used in the clinic and although more complex, adoptive lymphocyte transfer and CAR-T therapies show promise. We are learning that there are nuances to predicting the successful use of the checkpoint inhibitors as well as to specific-antigen adoptive and CAR-T therapies. We are also newly aware of a here-to-fore unrealised natural force, the status of the microbiome. However, despite better understanding of mechanisms of action of the new immune therapies, the best responses to the new immune therapies remain 20-30%. Likely the best way to improve this somewhat low response rate for patients is to increase the patient's own immune response. Thermal therapy is a way to do this. All forms of thermal therapy, from fever-range systemic thermal therapy, to high-temperature HIFU and even cryotherapy improve the immune response pre-clinically. It is time to test the immune therapies with thermal therapy in vivo to test for optimal timing of the combinations that will best enhance tumour response and then to begin to test the immune therapies with thermal therapy in the clinic as soon as possible.

Phase I trial of antigen-targeted autologous dendritic cell-based vaccine with in vivo activation of inducible CD40 for advanced prostate cancer.

This phase I trial reports the safety and activity of BPX101, a second-generation antigen-targeted autologous antigen presenting cell (APC) vaccine in men with metastatic castration-resistant prostate cancer (mCRPC). To manufacture BPX101, APCs collected in a single leukapheresis were transduced with adenoviral vector Ad5f35 encoding inducible human (ih)-CD40, followed by incubation with protein PA001, which contains the extracellular domain of human prostate-specific membrane antigen. The ih-CD40 represents a modified chimeric version of the dendritic cell (DC) co-stimulatory molecule, CD40, which responds to a bioinert membrane-permeable activating dimerizer drug, rimiducid (AP1903), permitting temporally controlled, lymphoid-localized, DC-specific activation. Eighteen men with progressive mCRPC following ≤1 prior chemotherapy regimen were enrolled to evaluate three doses of BPX101 (4 × 106, 12.5 × 106 and 25 × 106 cells) administered intradermally every 2-4 weeks followed by rimiducid (0.4 mg/kg) intravenous (IV) infusion 24 h after each BPX101 dose. There were no dose-limiting toxicities. Immune upregulation as well as anti-tumor activity was observed with PSA declines, objective tumor regressions and robust efficacy of post-trial therapy. This novel antigen-targeted and in vivo activated immunotherapy platform may warrant further development as monotherapy and as a component of rational combinations.

Fever-range whole body thermotherapy combined with oxaliplatin: a curative regimen in a pre-clinical breast cancer model.

PURPOSE: Studies were conducted to test whether fever-range whole body thermal therapy would boost the efficacy of oxaliplatin chemotherapy without substantial toxicity. MATERIALS AND METHODS: The effect of mild heat (40 degrees C) on oxaliplatin cytotoxicity, cellular uptake, and platinum-DNA adduct formation was studied in vitro using the MTLn3 tumour cell line. In vivo oxaliplatin was administered at various doses and times before, during and after fever-range thermal therapy (6 h at 40 degrees C) to rats bearing an MTLn3 mammary adenocarcinoma. Tumour growth, survival, and toxicity were measured to determine treatment outcome. RESULTS: Heating halved the oxaliplatin IC-50 dose for MTLn3 cells. Cellular uptake of platinum and platinum adducts increased by 34% and 36%, respectively, with heat. In vivo, 50% of all rats given 10 mg/kg oxaliplatin 24 h before thermal therapy were completely immunologically cured, while a further 11% regressed their primary tumour but ultimately succumbed to metastases, and 17% experienced a limited response with increased survival. The curative response occurred only in a narrow range of doses, with most cures at 10 mg/kg. Thermochemotherapy-treated, but uncured, animals had delayed incidence and slowed growth of metastases. Anti-tumour efficacy was greatest, and toxicity was least, when oxaliplatin was administered 12 or 24 h before fever-range whole body thermal therapy. CONCLUSIONS: When properly dosed and scheduled, oxaliplatin thermochemotherapy achieved permanent eradication of all primary and metastatic tumours in 50% of animals, seemingly through an immune response. Successful clinical translation of this protocol would yield hitherto unseen cures and substantial improvement in quality of life.

Fever-range whole-body thermal therapy combined with cisplatin, gemcitabine, and daily interferon-alpha: a description of a phase I-II protocol.

PURPOSE: The purpose of the Phase I component of this study was to find the maximally tolerated dose (MTD) of cisplatin administered within a regimen of fever-range whole body thermal therapy (FR-WB-TT), cisplatin, gemcitabine, and low-dose interferon-alpha (IFN-alpha). The Phase II component aimed to assess which cancer diagnoses responded to the regimen, the response rate, and response duration. MATERIALS AND METHODS: The protocol design derived from a schedule-optimized preclinical regimen. Drugs were administered together, and also with thermal therapy in a schedule that optimized the therapeutic index. Eligible patients were those with therapy-resistant, metastatic or advanced solid malignancies. Beginning at 40 mg/m(2), the cisplatin dose was escalated by 10 mg/m(2) to the maximally tolerated dose (MTD) in successive cohorts of 3 patients. A treatment cycle consisted of cisplatin on day one, followed by thermal therapy and simultaneous gemcitabine 36 hours later; then a second dose of gemcitabine one week later; and daily IFN- alpha. RESULTS: Thirty-seven patients were treated on protocol. The MTD of cisplatin in the thermochemotherapy regimen was established to be 60 mg/m(2). The dose limiting toxicities (DLT) were peripheral neuropathy and ototoxicity. Complete and partial responses combined were 43%. The therapy improved the quality of life of responding patients. CONCLUSION: The protocol was well tolerated and was associated with antitumor activity in patients with a variety of advanced metastatic solid tumors. Tumor response occurred with the thermochemotherapy treatment despite treating malignancies that had progressed on the same chemotherapy drugs administered as standard treatment. Notably, good responses were observed in patients with high-grade neuroendocrine and pancreas cancers. This regimen will be tested in a phase II study.

The natural progression of microvasculature in primary tumor and lymph node metastases in a breast carcinoma model: relationship between microvessel density, vascular endothelial growth factor expression, and metastatic invasion.

The natural course of tumor microvascularity in rat MTLn3 mammary adenocarcinomas was studied. The relationship between microvessel density (MVD), vascular endothelial growth factor (VEGF) expression, and histopathology was compared in primary and metastatic axillary (ALN) and inguinal lymph node (ILN) tumors over 5-6 tumor doublings. Excised tumors were examined for (i) MVD assessed by immunostaining with anti-CD31 antibody, (ii) VEGF expression assessed by immunostaining with anti-VEGF antibody, and (iii) histopathologic extent of metastatic lymph node invasion. MVD and VEGF scores rose asymptotically with increasing tumor weight in both primary and metastatic tumors. The MVD saturation level was significantly greater for primary tumors (MVD = 22) than for ALNs or ILNs (MVD = 14). Maximal VEGF score was not statistically different between the three kinds of tumors, however the rate of rise in VEGF expression was different. Near-maximal VEGF expression occurred early in tumor growth, preceding microvessel development. Both MVD and VEGF expression in lymph nodes were proportional to the pathology score characterizing increasing metastatic invasion. LNMs limited to the subcapsular sinus had the lowest MVD, indicating an ability to survive without significant vasculature. These findings underscore the differences in angiogenesis between primary tumors and LNMs and have implications for therapy of metastatic cancer.