DARC Diagnostic Test for Tumor Immunotherapy

Background & Unmet Need

• The Duffy Antigen Receptor for Chemokines (DARC), also known as Atypical Chemokine Receptor 1 (ACKR1), plays a major role in the regulation of circulating pro-inflammatory chemokines
• A mutation in the DARC/ACKR1 gene, rs2814778, results in a Duffy-null allele
• African American (AA) cohorts have over 70% allele frequency of this allele, and it is well known that pre-menopausal AA women have higher incident rates of breast cancer
• However, the impact of DARC expression on treatment outcomes is unknown
• Unmet Need: Improved understanding of the role of DARC expression to guide treatment decisions

Technology Overview

• The Technology: Method for measuring DARC expression levels as a prognostic indicator of a patient’s response to tumor immunotherapy
• The Discovery: Breast cancer patients with DARC-high tumors had significantly longer overall survival (OS) and relapse-free survival (RFS) compared to patients with DARC-low tumors
• DARC-high tumors were also found to have significantly higher levels of the chemokine CCL2 but significantly lower levels of the chemokine CXCL8
• Tumor immune cell populations were also found to be directly correlated to DARC expression, in all intrinsic tumor subtypes
• Patients with DARC-high tumors may be more responsive to immunotherapies (e.g., checkpoint inhibitors), whereas patients with DARC-low tumors may benefit from chemotherapy, radiation therapy, and surgery

Technology Applications

• Prognostic indicator of patient response to immunotherapies
• Predictor of long-term patient outcomes

Technology Advantages

• Strong correlation between DARC expression and breast cancer survival
• Test may be performed either through genetic testing or direct measurement of DARC protein levels
• Potential to be applied to additional tumor types beyond breast cancer