Despite the potential of immunotherapy (IO), a minority of patients respond to treatment. As effective IO treatments enhance T cell infiltration and activation, understanding T cell behavior is paramount for developing successful treatment strategies. Biopsies are used to assess T cell states, but are invasive and may not accurately reflect tumor burden. Positron emission tomography (PET) imaging holds promise as a non-invasive, comprehensive means for evaluating T cell activity.

The iRelate project aims to assess T cell presence and activation state using two PET ligands in clinical development: [89Zr]Zr-Df-IAB22M2C, a CD8a-targeting minibody developed by ImaginAb; and [18F]FAraG, a mitochondrial enzyme-targeting small molecule developed by CellSight. Using both PET tracers will enable characterization of tracer uptakes in tumor tissue and T-cell-rich organs and is expected to provide information on unique and additive capacities of these tracers. This work is intended to serve as a foundation for defining potential context of use for PET biomarkers, and to support the development and selection of successful IO treatment strategies.

  • Establish the extent to which [18F] F-AraG and [89Zr]Crefmirlimab tracers provide either overlapping or complementary uptake in tumors and T cell rich organs (e.g., spleen, lymph nodes)

  • Correlate the uptake and distribution of [18F]F-AraG and [89Zr]Crefmirlimab with the presence of CD8+ cells and T cell activation features as assessed in resected tissues

Partner with Us

The Foundation for the National Institutes of Health (FNIH) actively seeks private-sector funding and budget-relieving in-kind resources to support iRelate. The project seeks $3.2M in private funds over three years. The below chart outlines the contributions necessary for participation as a full-funding partner. The range of necessary financial contributions is ultimately dependent upon the number of participating funding partners.

Full-funding partners may have multiple participants on the Project Team and may cast one vote on project decisions. Throughout the life of the project, the FNIH will work to ensure that all partners have ample opportunity to provide input and share valuable expertise. Active participation and broad acknowledgement of all private partners will be facilitated through:

  • Participation on the Project Team and in regular Project Team teleconferences
  • Progress reports provided by the Project PIs and at least one face-to-face meeting per year
  • Collaboration with FNIH staff to ensure recognition in press releases, project-related print materials, the FNIH annual report, and the FNIH website.


Project Impact


Partner With Us

Work with the FNIH to accelerate medical breakthroughs for patients