The National Institutes of Health (NIH), through the National Cancer Institute (NCI) and National Institute of Dental and Craniofacial Research (NIDCR), has reissued a funding opportunity announcement (FOA) PAR-25-108 titled "Microbial-based Cancer Imaging and Therapy - Bugs as Drugs (R21 Clinical Trial Not Allowed)." This initiative invites exploratory and developmental research grant applications under the R21 mechanism to investigate the use of bacteria, bacteriophages, archaebacteria, or other non-oncolytic viruses in cancer treatment, diagnosis, or imaging. The program encourages innovative studies on microbial interactions with tumors and the immune system to overcome limitations of conventional cancer therapies and imaging techniques. Research under this FOA may focus on bacterial tumor homing, immunomodulation, and microbial metabolites as anti-cancer agents, with a focus on applications that could transform cancer care and expand therapeutic options.

Eligible research areas include developing microbial-based strategies for selective tumor targeting, anti-tumor immunity activation, and tumor imaging. The NCI is interested in applications related to solid tumors where standard therapies are often ineffective, including those addressing issues like hypoxia, metastatic resistance, and immune suppression. Additionally, NIDCR supports research focused on microbial therapies for cancers of the oral cavity, oropharynx, and salivary glands, including microbial delivery of therapeutics to these sites. The R21 mechanism is appropriate for projects at an early stage with limited preliminary data, aiming to establish proof of concept or basic functionality.

The total budget for each two-year project cannot exceed $275,000 in direct costs, with a cap of $200,000 in any given year. This program does not fund clinical trials; however, preclinical studies involving cell cultures or animal models are encouraged. Applicants must demonstrate multidisciplinary collaboration, integrating microbiology, oncology, immunology, and related fields, to develop comprehensive strategies for microbial-based cancer therapies. NIH will evaluate proposals based on significance, innovation, approach, and expertise, with additional consideration given to the potential for impactful scientific advances and real-world application in clinical settings.

Eligible applicants include higher education institutions, nonprofits, for-profit organizations, local governments, and foreign institutions. Proposals must be submitted electronically through Grants.gov or NIH ASSIST. Application deadlines for 2025 are February 16 and March 16, with awards expected to be announced starting in July 2025. Additional guidance and details are available, and prospective applicants can contact NIH representatives, including Dr. Avi Rasooly and Dr. Zhong Chen, for specific research inquiries.