In response to the specific FOA that explicitly focuses on microbial-based cancer therapy (Bugs as Drugs), we
propose to develop reliable multimodal MRI guidance to improve the efficacy and safety of bacterial cancer
therapies for treating poorly vascularized, hypoxic tumors, where conventional cancer therapies are inadequate.
Even though some have managed to reach clinical trial status, the development of microbial-based therapeutics
for solid tumors has been long hindered by inconsistent results. Researchers in the field of microbial-based
therapeutics have a major problem of inadequate and inconsistent means of guiding, monitoring, and assessing
results of administered microbial therapy. Currently, the patient recruitment criteria for bacterial therapy are not
specific and suitability is mainly judged by tumor size. The surrogate markers for bacterial germination/infection
are radiological signs of tumor destruction and/or clinical signs and symptoms of systemic infection. There is an
urgent need for developing noninvasive imaging tools that can identify patients who likely respond (stratification)
by tumor hypoxia and real-time, quantitively measure the germination and proliferation of therapeutic bacteria in
target tumors. To address these unmet needs, we will develop and optimize two emerging imaging technologies
in this study: a) bacteria-detecting Chemical Exchange Saturation Transfer (CEST) MRI method (namely
bacCEST) to assess bacterial infection in the tumor, serving as a non-invasive means to monitor therapeutic
effects and adjust the treatment plan, and b) Oxygen-Enhanced (OE) MRI to characterize tumor hypoxia and
hence predict the tumors’ vulnerability to anaerobic bacteria. We hypothesize that that the efficacy and safety of
bacterial treatment can be significantly improved using non-invasive, multimodal MRI methods that can
characterize tumor hypoxia prior to treatment and monitor bacterial infection at early time points. We have strong
preliminary data demonstrating the efficacy of C. novyi-NT and capabilities of advanced MRI technologies, and
gathered a multidisciplinary team of oncologists and imaging experts to complete the following aims: 1) Establish
bacteria-detecting bacCEST MRI as a surrogate marker for C. novyi-NT treatment, 2) Establish hypoxia-
detecting OE MRI to stratify tumors and guide bacterial treatment, and 3) Establish multimodal MRI guidance to
improve the efficacy and safety of bacterial cancer therapy. Successful completion of the proposed study will
provide approaches for multimodal MRI guidance that can ultimately improve the success rate of cancer
therapies using anaerobic bacteria, including but not limited to C. novyi-NT. This MRI platform technology, once
translated to human scanners, will address an unmet need in bacterial treatment and can accelerate the
development and clinical testing of bacterial therapies. It will also benefit other areas in medicine (e.g., infection
medicine/sepsis), thereby pushing clinical capabilities forward.