Search

Abstract In this White Paper, we discuss the current state of microbial cancer therapy. This paper resulted from a meeting (‘Microbial Based Cancer Therapy’) at the US National Cancer Institute in the summer of 2017. Here, we define ‘Microbial Therapy’ to include both oncolytic viral therapy and bacterial anticancer therapy. Both of these fields exploit tumor-specific infectious microbes to treat cancer, have similar mechanisms of action, and are facing similar challenges to commercialization. We designed this paper to nucleate this growing field of microbial therapeutics and increase interactions between researchers in it and related fields. The authors of this paper include many primary researchers in this field. In this paper, we discuss the potential, status and opportunities for microbial therapy as well as strategies attempted to date and important questions that need to be addressed. The main areas that we think will have the greatest impact are immune stimulation, control of efficacy, control of delivery, and safety. There is much excitement about the potential of this field to treat currently intractable cancer. Much of the potential exists because these therapies utilize unique mechanisms of action, difficult to achieve with other biological or small molecule drugs. By better understanding and controlling these mechanisms, we will create new therapies that will become integral components of cancer care.

Abstract Background Cigarette smoke exposure is the major risk factor for developing COPD. Presently, available COPD treatments focus on suppressing inflammation and providing bronchodilation. However, these options have varying efficacy in controlling symptoms and do not reverse or limit the progression of COPD. Treatments strategies using bacterial-derived products have shown promise in diseases characterized by inflammation and immune dysfunction. This study investigated for the first time whether a novel immunotherapy produced from inactivated Klebsiella (hereafter referred to as KB) containing all the major Klebsiella macromolecules, could attenuate cigarette smoke exposure-induced immune responses. We hypothesized that KB, by re-directing damaging immune responses, would attenuate cigarette smoke-induced lung inflammation and bronchoalveolar (BAL) cytokine and chemokine production. Methods KB was administered via a subcutaneous injection prophylactically before initiating a 3-week acute nose-only cigarette smoke exposure protocol. Control mice received placebo injection and room air. Total BAL and differential cell numbers were enumerated. BAL and serum were analysed for 31 cytokines, chemokines, and growth factors. Lung tissue and blood were analysed for Ly6CHI monocytes/macrophages and neutrophils. Body weight and clinical scores were recorded throughout the experiment. Results We demonstrate that KB treatment attenuated cigarette smoke-induced lung inflammation as shown by reductions in levels of BAL IFNγ, CXCL9, CXCL10, CCL5, IL-6, G-CSF, and IL-17. KB additionally attenuated the quantity of BAL lymphocytes and macrophages. In parallel to the attenuation of lung inflammation, KB induced a systemic immune activation with increases in Ly6CHI monocytes/macrophages and neutrophils. Conclusions This is the first demonstration that subcutaneous administration of a microbial-based immunotherapy can attenuate cigarette smoke-induced lung inflammation, and modulate BAL lymphocyte and macrophage levels, while inducing a systemic immune activation and mobilization. These data provide a foundation for future studies exploring how KB may be used to either reverse or prevent progression of established emphysema and small airways disease associated with chronic cigarette smoke exposure. The data suggest the intriguing possibility that KB, which stimulates rather than suppresses systemic immune responses, might be a novel means by which the course of COPD pathogenesis may be altered.

Background: Current Crohn's disease (CD) therapies focus on suppressing immune function and come with consequent risk, such as infection and cancer. Notwithstanding, most CD patients still experience disease progression. There is a need for new CD treatment strategies that offer better health outcomes for patients.Aims: To assess safety, efficacy, and tolerability of a novel microbial-derived immunotherapy, QBECO, that aims to restore rather than suppress immune function in CD.Methods: A randomized, double-blind, placebo-controlled trial was conducted in 68 patients with moderate-to-severe CD. Primary endpoints: safety and Week 8 clinical improvement. Secondary endpoints: Week 8 clinical response and remission. Week 8 responders continued blinded treatment through Week 16; non-responders received open-label QBECO from Weeks 9–16. Exploratory analyses included immune biomarker and genotype assessments.Results: QBECO was well-tolerated. Mean reduction in Crohn's Disease Activity Index (CDAI) score was −68 for QBECO vs. −31 for placebo at Week 8. Improvement with QBECO continued through Week 16 (-130 CDAI reduction). Week 8 QBECO clinical response, improvement and remission rates were 41.2%, 32.4%, 29.4% vs. 26.5%, 23.5%, 23.5% for placebo. TNFα inhibitor-naïve subjects achieved higher response rates at Week 8 with QBECO (64%) vs. placebo (26%). Specific immune biomarkers were identified that linked to QBECO response.Conclusion: This proof-of-concept study supports further investigation for the use of QBECO as a novel immunotherapy approach for CD. Biomarker analyses suggests it may be feasible to personalize CD treatment with QBECO. Larger trials are now needed to confirm clinical improvement and the unique biological findings.Clinical Trial Number: NCT01809275 (https://clinicaltrials.gov/ct2/show/NCT01809275)

Background: Current ulcerative colitis (UC) treatments are focused on symptom management primarily via immune suppression. Despite the current arsenal of immunosuppressant treatments, the majority of patients with UC still experience disease progression. Importantly, aggressive long-term inhibition of immune function comes with consequent risk, such as serious infections and malignancy. There is thus a recognized need for new, safe and effective treatment strategies for people living with UC that work upstream of managing the symptoms of the disease. The objective of this study was to evaluate a microbial-based treatment, QBECO, that functions to productively activate rather than suppress mucosal immune function as a novel approach to treat UC.Methods: Two established models of experimental colitis, namely chemically-induced DSS colitis and the spontaneous colitis that develops in Muc2 deficient mice, were used to assess whether QBECO treatment could ameliorate gastrointestinal disease. A small exploratory 16-week QBECO open-label trial was subsequently conducted to test the safety and tolerability of this approach and also to determine whether similar improvements in clinical disease and histopathology could be demonstrated in patients with moderate-to-severe UC.Results: QBECO treatment successfully reduced inflammation and promoted mucosal and histological healing in both experimental models and in UC patients. The preclinical models of colitis showed that QBECO ameliorated mucosal pathology, in part by reducing inflammatory cell infiltration, primarily that induced by neutrophils and inflammatory T cells. The most rapid and noticeable change observed in QBECO treated UC patients was a marked reduction in rectal bleeding.Conclusion: Collectively, this work demonstrates for the first time that strategically activating immune function rather than suppressing it, not only does not worsen colitis induced-damage, but may lead to an objective reduction in UC disease pathology.

Acute infection is known to induce strong anti-tumor immune responses, but clinical translation has been hindered by the lack of an effective strategy to safely and consistently provoke a therapeutic response. These limitations are overcome with a novel treatment approach involving repeated subcutaneous delivery of a Klebsiella-derived investigational immunotherapeutic, QBKPN. In preclinical models of lung cancer, QBKPN administration consistently showed anti-cancer efficacy, which was dependent on Klebsiella pre-exposure, but was independent of adaptive immunity. Rather, QBKPN induced anti-tumor innate immunity that required NK cells and NKG2D engagement. QBKPN increased NK cells and macrophages in the lungs, altered macrophage polarization, and augmented the production of cytotoxic molecules. An exploratory trial in patients with non-small cell lung cancer demonstrated QBKPN was well tolerated, safe, and induced peripheral immune changes suggestive of macrophage polarization and reduction of PD-1 and PD-L1 expression on leukocytes. These data demonstrate preclinical efficacy, and clinical safety and tolerability, for this cancer immunotherapy strategy that exploits innate anti-tumor immune mechanisms.

We investigated the mechanism of action, safety, and efficacy of the Site-Specific Immunomodulator (SSI) QBECO, a novel immunotherapy for Crohn’s disease (CD). Using human monocytic THP-1 cells, we demonstrate that SSI QBECO (derived from the common colon bacteria E. coli) activates macrophages to an M1 phenotype (associated with enhanced capacity to eliminate bacteria and activate innate immune responses). We assessed SSI QBECO in a compassionate use protocol of ten adult patients with active CD. Patients with moderate to severe clinical symptoms receiving conventional CD treatments and/or complementary therapies were included, except patients receiving anti-TNF medications. SSI QBECO was self-administered subcutaneously every second day, for a minimum of 2.5 months and a maximum of 11 months. All 10 patients reported improvement of symptoms while on the SSI QBECO treatment. Seven patients reported full resolution of clinical symptoms during a course of SSI QBECO of at least three months. Three patients have experienced ongoing sustained clinical remission after discontinuing all medications, including SSI treatment. The longest case of clinical remission is still ongoing (>4 years). No serious severe adverse clinical events were reported. Collectively, we conclude that treatment with the immunoactive SSI QBECO was well tolerated and effective for treatment of Crohn’s disease in this case series.

Acute infection is known to induce strong anti-tumor immune responses, but clinical translation has been hindered by the lack of an effective strategy to safely and consistently provoke a therapeutic response. These limitations are overcome with a novel treatment approach involving repeated subcutaneous delivery of a Klebsiella-derived investigational immunotherapeutic, QBKPN. In preclinical models of lung cancer, QBKPN administration consistently showed anti-cancer efficacy, which was dependent on Klebsiella pre-exposure, but was independent of adaptive immunity. Rather, QBKPN induced anti-tumor innate immunity that required NK cells and NKG2D engagement. QBKPN increased NK cells and macrophages in the lungs, altered macrophage polarization, and augmented the production of cytotoxic molecules. An exploratory trial in patients with non-small cell lung cancer demonstrated QBKPN was well tolerated, safe, and induced peripheral immune changes suggestive of macrophage polarization and reduction of PD-1 and PD-L1 expression on leukocytes. These data demonstrate preclinical efficacy, and clinical safety and tolerability, for this cancer immunotherapy strategy that exploits innate anti-tumor immune mechanisms. [ABSTRACT FROM AUTHOR]