# Multiplexed time domain fluorescence tomography of tumor biomarkers during immunotherapy

> **NIH NIH R01** · MASSACHUSETTS EYE AND EAR INFIRMARY · 2024 · $436,422

## Abstract

Abstract: Immunotherapy using programmed death 1 receptor (PD-1) blockade, either alone or in
combination with existing therapies, has been proven to significantly improve survival rates for many
cancers, including triple negative breast cancer (TNBC). However, only about a quarter of the
patients respond to treatment, typically those with programmed death ligand 1 (PD-L1)-positive
tumors, while a majority experience serious drug related side effects. The efficient selection of likely
responders to immunotherapy is limited by the fact that biopsy, the current screening standard for
PD-L1 expression, provides only a snapshot of biomarker status at a single time point, while it is
known that PD-L1 expression can dynamically change during therapy. Additionally, tumor vascular
“normalization” indicators, such as perfusion, hypoxia and angiogenesis can dynamically change
during treatment, potentially serving as early indicators of treatment efficacy. There is therefore an
urgent need for non-invasive imaging techniques that can longitudinally quantify molecular and
physiological predictive tumor biomarkers before and during treatment. Such techniques can
potentially save non-responders from ineffective treatment and life-threatening effects and can also
facilitate a robust evaluation of new combination therapies that improve survival and prove effective in
a larger patient population. Our preliminary studies using time domain fluorescence imaging indicate
that the fluorescence lifetime (FLT) of immune-receptor targeted near infrared probes is longer in PD-
L1 positive tumors compared to non-specific probe in normal tissue, thereby dramatically improving
sensitivity and specificity compared to fluorescence intensity-based imaging. Furthermore, time
domain imaging allows the simultaneous detection and quantification of multiple fluorophores using
spectral and lifetime contrast (multiplexing) and is therefore ideal for imaging multiple molecular and
physiologic parameters of treatment response. The goal of this proposal is to translate these powerful
benefits of FLT to validate tomographic FLT imaging as a new tool for multiplexed longitudinal
monitoring of biomarkers during immunotherapy. We will validate the accuracy of the optical readouts
for monitoring therapeutic response longitudinally in TNBC-bearing mice by comparison with
histology. The feasibility of fluorescence imaging has previously been demonstrated for superficial
lymph nodes and for organs such as the breast. Therefore, validation of FLT multiplexing in
preclinical models is a fundamental step that will lead to targeted clinical trials to evaluate TD
technology for non-invasive functional immunotherapy screening in TNBC patients.

## Key facts

- **NIH application ID:** 10810859
- **Project number:** 5R01CA260857-05
- **Recipient organization:** MASSACHUSETTS EYE AND EAR INFIRMARY
- **Principal Investigator:** Dan Gabriel Duda
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $436,422
- **Award type:** 5
- **Project period:** 2021-04-01 → 2026-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10810859

## Citation

> US National Institutes of Health, RePORTER application 10810859, Multiplexed time domain fluorescence tomography of tumor biomarkers during immunotherapy (5R01CA260857-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10810859. Licensed CC0.

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