# A Circulating Biomarker for use in Monitoring Metastatic Breast Cancer

> **NIH NIH R44** · A AND G PHARMACEUTICAL, INC. · 2021 · $141,660

## Abstract

Cost-effective and minimally invasive monitoring of metastatic breast cancer (MBC) patients for disease
progression or response to therapy is an unmet need in the clinical management of the disease. Imaging
technologies are currently the gold standard of such monitoring. However, there is controversy regarding the
type & frequency of imaging required. Imaging is expensive, time consuming, slow to detect disease changes
and raises concern about repeated radiation exposure and costs are not always covered by insurance.
Complementary approaches to imaging such as circulating tumor cells and biomarkers are used in the Standard
of Care (SOC), although their application remains limited. A simple, cost-effective blood test to measure the level
of biomarkers which are drivers of the disease aggressiveness should provide novel solutions for real-time
monitoring of therapy response and reduce dependency on imaging in the MBC population. The PI has identified
an 88kDa glycoprotein GP88 (progranulin), elucidated its biological activity as an autocrine growth & survival
factor. GP88 is secreted from cancer cells and measurable in biological fluids at higher levels in breast cancer
patients, compared to healthy individuals. Based on these characteristics, an innovative diagnostic test (Enzyme
Immunoassay – EIA) to measure GP88 in circulation was established. Our SBIR Phase 1 retrospective study
demonstrated a statistical association between serum GP88 levels measured by the EIA test and objective
measures of disease, i.e. RECIST 1.1 in 101 MBC patients. We established that a serum GP88 level of 56ng/mL
was a stratification point below which patients have improved overall survival while patients with GP88>56 ng/ml
have a poor outcome. We showed that serum GP88 levels were statistically correlated to response to therapy in
addition to progression of disease unlike the SOC biomarker CA15-3 which is only associated to progression of
disease. Based on these promising data, we are proposing an SBIR Phase 2 prospective longitudinal study over
a 15-month period enrolling 120 MBC patients at two clinical sites by measuring serum GP88 level every month
with imaging performed every 3 months. The objectives are to validate the findings of phase 1 and establish the
predictive use of the GP88 test in monitoring MBC patients for disease progression/ response as an adjunct to
imaging and aid in the clinical management of such patients. Specifically, we will (1) Validate that serum GP88
levels are correlated to disease response/ progression as defined by imaging results; (2) Examine the impact of
successive high (>56ng/mL) and low (<56ng/mL) GP88 blood levels on future response/ progression and time
to progression as defined by imaging results; (3) Validate that patients with consistent low (<56ng/mL) GP88
blood levels, have improved survival compared with patients with consistently high (>56ng/mL) GP88 blood
levels. The outcomes of this phase 2 will be to establish clinical d...

## Key facts

- **NIH application ID:** 9768982
- **Project number:** 5R44CA210817-03
- **Recipient organization:** A AND G PHARMACEUTICAL, INC.
- **Principal Investigator:** Ginette Serrero
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $141,660
- **Award type:** 5
- **Project period:** 2017-03-15 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9768982

## Citation

> US National Institutes of Health, RePORTER application 9768982, A Circulating Biomarker for use in Monitoring Metastatic Breast Cancer (5R44CA210817-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9768982. Licensed CC0.

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