# Validation of Platelet Expression of FcɣRIIa as a Precision Tool

> **NIH NIH R44** · PROLOCOR INC. · 2022 · $613,937

## Abstract

ABSTRACT
The American Heart Association estimates that, in 2022, about 720,000 Americans will have a first coronary
event and 335,000 will have a recurrent event, of which, approximately 87% are ischemic (thrombotic). Anti-
thrombotic therapy reduces the risk of recurrent ischemic events at the cost of a greater incidence of bleeding
complications. Patients at low thrombotic/ischemic risk should benefit from shortened treatment whereas patients
at high thrombotic/ischemic risk should derive greater absolute benefit from longer term treatment with more
powerful antiplatelet therapy. Currently available tools such as clinical risk scores and platelet function testing
are inadequate to effectively individualize cardiovascular care, and effective precision medicine strategies to
enable clinicians to target patients with high residual risk are lacking. Platelet function tests effectively identify
patients at risk but failed when used in trials designed to guide treatment. Key weaknesses of platelet function
tests include that they demonstrate substantial intra-individual variability, are influenced by both assay conditions
as well as the treatment of the patient, and that they measure platelet reactivity in response to a select agonist
or group of agonists. To address this gap in patient care, Prolocor identified a biomarker, FcγRIIa, on the surface
of platelets. When platelets activate, FcγRIIa amplifies platelet activation. Thus, increased platelet FcγRIIa
increases platelet reactivity and leverages the prognostic implications of platelet function tests. Compared to
currently available platelet function tests, expression of FcγRIIa shows less intra-individual variability, is
substantially less sensitive to perturbations related to assay conditions, and predicts increased platelet reactivity
in response to a variety of agonists. In a preliminary study of 197 patients, Cox regression analysis demonstrated
that platelet expression of FcγRIIa was the sole covariate (hazard ratio 3.9, p=0.035) associated with an
increased risk of heart attack, stroke, and death when age, diabetes, and prior revascularization were included
as covariates. Thus, quantifying platelet FcγRIIa expression is a novel method to identify cardiovascular risk and
should serve as a powerful precision medicine tool. Prolocor has since refined the assay by developing
antibodies that bind to FcyRIIa on the surface of platelets that have been fixed with formaldehyde. Initial analytic
testing has demonstrated excellent precision (coefficient of variation of repeated tests <5%). The Proposed SBIR
is designed to provide comprehensive analytic validation of the assay in accordance with FDA Quality System
Regulation, demonstrating that the measurement of platelet FcɣRIIa expression is accurate, precise, and
reproducible. The analytic validation will be paired with clinical validation provided by prospective observational
studies in acute coronary syndrome, stroke and cancer. The combination o...

## Key facts

- **NIH application ID:** 10545286
- **Project number:** 1R44HL166003-01
- **Recipient organization:** PROLOCOR INC.
- **Principal Investigator:** Jeanne Ohrnberger
- **Activity code:** R44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $613,937
- **Award type:** 1
- **Project period:** 2022-08-11 → 2025-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10545286

## Citation

> US National Institutes of Health, RePORTER application 10545286, Validation of Platelet Expression of FcɣRIIa as a Precision Tool (1R44HL166003-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10545286. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*