See Early Immunotherapy Signals in Days, Not Months

CSB-321’s PET radiodiagnosticCytoSite BIO’s radiodiagnostic is delivered intravenously at a hospital or clinic. is designed to enable a ≈14-day readout of treatment effect. It delivers an early, tumor-by-tumorLesion-level = per individual tumor/metastasis (tumor-by-tumor). signal, rather than waiting 6+ months for size or metabolic changes on CT/MRI/FDG.Compared to conventional imaging or lab markers that require longer intervals or only indicate potential activity, CSB-321 provides an earlier, actionable signal.^{[II]Comparative & timing context. Statements comparing CSB-321 to CT/MRI/FDG or lab markers, and any earlier readout claims (e.g., ≈approximately 14 days), are context-specific to the study protocols (acquisition timing, analysis methods, reader criteria) and do not guarantee individual outcomes, regulatory decisions, or clinical benefits.}

Why that matters. Our CSB-321 and PET scan imaging data help clinicians decide to continue or switch therapies sooner, and therapeutic developers can make earlier go/no-go decisions, saving millions in failed trials.^{[III]Economic/operational impact. References to cost/time savings, de-risking, shorter trials, and earlier go/no-go reflect potential operational advantages observed or anticipated in studies; they do not guarantee lower overall development costs, faster approvals, or commercial success.}

CSB-321CytoSite BIO’s radiodiagnostic is delivered intravenously at a hospital or clinic. is a tracer that binds to a small percentage of granzyme B,^{[I]Investigational / availability / performance variability. CSB-321 is an investigational agent and has not been approved for commercial use. Availability is limited to clinical studies or other authorized investigational use. Timing, safety, and performance (including frequency of scanning, sensitivity/specificity, and readout intervals) are study, indication, therapy, site, and patient-dependent.} the weapon NK/T cells use to kill cancer. On a PET scan, the tracer accumulates where granzyme B is actively attacking tumors. But, we go beyond the picture—we convert the scan image into quantitative, lesion-by-lesion (tumor-by-tumor) data you can track and compare visit-to-visit and tumor-by-tumor. The PET scanner counts the paired bindings around the body and normalizes the data by injected dose and body size to produce standard PET numbers (e.g., SUV).

Unlike alternative scans that often require months to show size changes or lab tests that only indicate potential, CSB-321 provides real-time, immune-measurable data.^{[II]Comparative & timing context. Statements comparing CSB-321 to CT/MRI/FDG or lab markers, and any earlier readout claims (e.g., ≈approximately 14 days), are context-specific to the study protocols (acquisition timing, analysis methods, reader criteria) and do not guarantee individual outcomes, regulatory decisions, or clinical benefits.}

Why this matters. Our readouts provide faster, earlier, decision-ready data you can measure and repeat—supporting go/no-go calls, adaptive planning, and apples-to-apples comparisons across time points and sites.^{[III]Economic/operational impact. References to cost/time savings, de-risking, shorter trials, and earlier go/no-go reflect potential operational advantages observed or anticipated in studies; they do not guarantee lower overall development costs, faster approvals, or commercial success.}

CSB-321CytoSite BIO’s radiodiagnostic is delivered intravenously at a hospital or clinic. is a low-dose, short-lived PET tracer built for repeat use.^{[I]Investigational / availability / performance variability. CSB-321 is an investigational agent and has not been approved for commercial use. Availability is limited to clinical studies or other authorized investigational use. Timing, safety, and performance (including frequency of scanning, sensitivity/specificity, and readout intervals) are study, indication, therapy, site, and patient-dependent.} You can run it on a 2–4-week cadenceTypical interval 2–4 weeks per protocol; short-half-life PET isotope with ALARA (As Low As Reasonably Achievable) dosing; quantitative repeatability via SUVmax/SUVmean, TBR, lesion-to-background using a standardized acquisition/analysis workflow. (per protocol, up to five scans/year), and it produces consistent, whole-body, tumor-level measures you can compare across visits.^{[I]Investigational / availability / performance variability. CSB-321 is an investigational agent and has not been approved for commercial use. Availability is limited to clinical studies or other authorized investigational use. Timing, safety, and performance (including frequency of scanning, sensitivity/specificity, and readout intervals) are study, indication, therapy, site, and patient-dependent.} Compared with serial CT/FDG PET (higher cumulative dose; often slower to reflect change) or repeat biopsies (invasive, single-site), CSB-321 supports protocol-guided, less invasive, repeat monitoring.^{[II]Comparative & timing context. Statements comparing CSB-321 to CT/MRI/FDG or lab markers, and any earlier readout claims (e.g., ≈approximately 14 days), are context-specific to the study protocols (acquisition timing, analysis methods, reader criteria) and do not guarantee individual outcomes, regulatory decisions, or clinical benefits.}

Why this matters. The result is fewer futile cycles for non-responders, earlier pivots to alternatives, and lower potential toxicity exposure. In trials, this supports earlier futility/efficacy decisions, cleaner datasets, and the ability to reallocate drug supply, site time, and budget toward responsive cohorts—de-risking late-stage spend by stopping underperforming arms sooner and helping reduce per-patient costs.^{[III]Economic/operational impact. References to cost/time savings, de-risking, shorter trials, and earlier go/no-go reflect potential operational advantages observed or anticipated in studies; they do not guarantee lower overall development costs, faster approvals, or commercial success.}

Our CSB-321 radiodiagnosticCytoSite BIO’s radiodiagnostic is delivered intravenously at a hospital or clinic. generates a whole-body, tumor-by-tumor mapLesion-level = per individual tumor/metastasis (tumor-by-tumor). that potentially shows—for each patient—which tumor sites are responding to a drug and which aren’t.^{[I]Investigational / availability / performance variability. CSB-321 is an investigational agent and has not been approved for commercial use. Availability is limited to clinical studies or other authorized investigational use. Timing, safety, and performance (including frequency of scanning, sensitivity/specificity, and readout intervals) are study, indication, therapy, site, and patient-dependent.} Instead of waiting months for size changes or relying on blood/tissue averages, teams get early, site-specific data they can act on.^{[II]Comparative & timing context. Statements comparing CSB-321 to CT/MRI/FDG or lab markers, and any earlier readout claims (e.g., ≈approximately 14 days), are context-specific to the study protocols (acquisition timing, analysis methods, reader criteria) and do not guarantee individual outcomes, regulatory decisions, or clinical benefits.} It turns active immune attack into quantifiable, repeatable, per-tumor-site scoresPer-lesion (lesion-level) quantitation via SUV/TBR with standardized acquisition/analysis; consistent VOI rules across timepoints. that you can track from visit to visit.^{[I]Investigational / availability / performance variability. CSB-321 is an investigational agent and has not been approved for commercial use. Availability is limited to clinical studies or other authorized investigational use. Timing, safety, and performance (including frequency of scanning, sensitivity/specificity, and readout intervals) are study, indication, therapy, site, and patient-dependent.}

Why this matters. Our goal is to keep therapies that work, locally treat or biopsy non-responders, or switch treatments sooner when disease is globally non-responsive—cutting futile cycles, spare patients unnecessary toxicity and cost—all while aligning trial choices to the patient’s actual biology. In trials, it enables earlier go/no-go decisions and smarter allocation of sites, drug supply, and budget.^{[III]Economic/operational impact. References to cost/time savings, de-risking, shorter trials, and earlier go/no-go reflect potential operational advantages observed or anticipated in studies; they do not guarantee lower overall development costs, faster approvals, or commercial success.}