A prototype diagnostic for cellular fetal hemoglobin in sickle cell disease

Period of Performance: 08/01/2016 - 01/31/2017

$225K

Phase 1 SBIR

Recipient Firm

Myosyntax Corporation
Brookline, MA 02446
Principal Investigator
Principal Investigator

Abstract

PROJECT SUMMARYSickle cell disease is a major clinical problem in the US, France, the United Kingdom, Brazil, and in Africa,India and the Middle East. A recent study shows that the annual cost of medical care in the US for people whosuffer from sickle cell disease exceeds $1.1 billion. Sickle hemoglobin (HbS) polymerization drives thepathophysiology of this disease. Fetal hemoglobin (HbF) is present throughout fetal development and isreplaced by adult hemoglobin (HbA). A major therapeutic goal in sickle cell disease is to induce high HbFlevels in sickle erythrocytes. We contend that the amount of HbF per F-cell (HbF/F-cell) and the distribution ofconcentrations of HbF/F-cells is a critical determinant of disease severity. Existing measurement of hemolysateHbF concentration or the number of F-cells in blood does not measure HbF/F-cell or the distribution of HbF/F-cell in a patient blood sample. This unmet need is critical because even patients with high HbF can havesevere disease since their HbF is unevenly distributed among F-cells and many F-cells have insufficient HbFconcentrations to inhibit HbS polymerization. We hypothesize that the proportion of F-cells that have enoughHbF to thwart HbS polymerization is the most critical predictor of the likelihood of severe sickle cell disease.HbF/F-cell should be the phenotype studied in HbF induction therapeutics and would also be useful indeveloping risk scores that project likelihoods for disease severity.A clinical method for rapidly ascertaining HbF/F-cell is currently not available. As HbF concentrations among F-cells are highly variable and clinically relevant, the predictive value of HbF would be improved with an assaymeasuring the distribution of HbF concentrations within F-cells. Physicians would be able to provide better careusing an HbF diagnostic as a standard method to assess which patients have higher risk, as well thosepatients with lower risk. Analysis of 20 sickle cell donors resulted in statistically significant associationsbetween HU treatment efficacy and F-cell frequency, but did not confirm other risk associations. We expect touse a Bayesian classifier to associate different distributions of concentration of HbF/F-cell to patient clinicaldata and overall severity.AIM 1. Develop a ?gold standard? method to validate an HbF/F-cell diagnosticIn this aim, we will develop and optimize the absolute quantitation of HbF by HPLC to provide a ?gold standard?validation of MyoSyntax?s HbF/F-cell diagnostic, which can determine the risk of sickle cell disease crisis.Absolute determination of HbF (pg/cell) via HPLC will be completed to precisely and absolutely correlate F-cellMFI to HbF quantity. This method will be used to qualify microsphere calibrators according to an FDA-approved clinical standard.AIM 2. Evaluate diagnostic performance in the prediction of sickle cell crisis risk in humansWe will evaluate the assay performance, in terms of specificity and sensitivity, with a spectrum of total HbFlevels and disease phenotypes to determine distributions of HbF/F-cell and their association with diseaseseverity among sickle cell individuals. The prognostic performance of HbF/F-cell will be contrasted to thecurrent clinical diagnostic standard, total HbF content expressed as a percent-mean. This will provide thepreliminary data we believe would justify a Phase II SBIR application.The long-term goal is to develop a test for HbF/F-cell profiling and a license for use of an online tool fordisease risk determination that can be done in any hospital with flow cytometry and internet capability.