A&G Pharmaceutical, Inc. and Precision Antibody Develop Sandwich ELISA for Metastatic Breast Cancer Clinical Studies

COLUMBIA, Maryland, September 7, 2020: A&G Pharmaceutical Inc., and its Custom Antibody Division Precision Antibody’s Progranulin ELISA kit used to investigate the correlation between progranulin serum level and disease status and survival in metastatic breast cancer patients.

When A&G Pharmaceutical and the University of Maryland Greenebaum Comprehensive Cancer Center initiated a study to examine the correlation between serum progranulin/GP88 level, a tumorigenesis driver and breast cancer progression, they needed to develop a reliable sandwich ELISA assay. A&G tasked its service division Precision Antibody (PA) to develop an assay able to measure serum and plasma GP88 that would be appropriate for the clinical study.

PA, known for its fast timeline and high success rate, developed specific human progranulin/GP88 monoclonal antibodies. PA then used Octet analysis to select antibodies with the best biochemical characteristics (high affinity, low off rate) for establishing a suitable sandwich ELISA. The Quantitative Progranulin ELISA developed is so sensitive that it can be used with biological samples known for their low progranulin/GP88 level such as cerebrospinal fluid, in addition to serum and plasma. This ELISA allows for Progranulin/GP88 investigation in neurogenerative diseases and for the detection of CNS metastasis1.

This work resulted in a study by Tkaczuk et al, entitled Association of Serum Progranulin Levels with Disease Progression, Therapy response and Survival in Patients with Metastatic Breast Cancer published in Clin. Breast Cancer, 2020, Vol 20, 220-227. This study which enrolled 100 patients with metastatic breast cancer (MBC) established a strong correlation between progranulin/GP88 serum level and survival. MBC patients with lower levels of progranulin/GP88 had a four-fold increase in survival compared to Patients with serum Progranulin above the threshold level of 55ng/ml. The study also established that measuring serum progranulin/GP88 had clinical utility not only for monitoring patients’ progression of disease but also response to therapy. In contrast, our study confirmed that serum CA15-3, currently used in the standard of care for monitoring metastatic breast cancer patients only showed an association with progression of disease.
While de novo MBC counts for 6% of the 250,000 annual breast cancer diagnosis in the US, it represents the majority of the yearly 40,500 deaths. Only 27 % of MBC patients survive 5 years after diagnosis of advanced breast cancer. MBC is considered a mostly incurable disease and poses several challenges to the clinical management with the goal of reducing treatment toxicity, providing improved Quality of Life and improving overall survival (OS). Thus, the ability to detect and monitor metastatic disease is important in the overall management of MBC.
Our promising results indicate that measuring Progranulin in addition to CA15-3 provide additional and complementary data to the clinicians to monitor metastatic breast cancer patients’ disease status. These results also complement our previous findings showing that high level of progranulin/GP88 expression in paraffin embedded tumor tissues is associated with increased recurrence and mortality for early-stage breast cancer patients. At present, determination of response to therapy during treatment for MBC involves various imaging techniques typically performed at intervals between 6-12 weeks, causing increased exposure of patients to radiation and significantly increasing the overall cost of care. The association of serum GP88 level with survival and disease status suggests the potential of using serum GP88 test for monitoring disease status in MBC patients. Measurement of serum GP88 levels in MBC patients may have clinical value as a cost-effective adjunctive to imaging MBC patient management along with other serum biomarkers already used in the standard of care.

To read the full research paper:

For more information regarding A&G’s Progranulin/GP88 research please see:
1 Higher levels of progranulin in cerebrospinal fluid of patients with lymphoma and carcinoma with CNS metastasis.

Kimura A, Takemura M, Serrero G, Yoshikura N, Hayashi Y, Saito K, Inuzuka T.
J Neurooncol. 2018 May;137(3):455-462. doi: 10.1007/s11060-017-2742-z. Epub 2018 Jan 16.
PMID: 29340960
2 Progranulin (GP88) tumor tissue expression is associated with increased risk of recurrence in breast cancer patients diagnosed with estrogen receptor positive invasive ductal carcinoma.

Serrero G, Hawkins DM, Yue B, Ioffe O, Bejarano P, Phillips JT, Head JF, Elliott RL, Tkaczuk KR, Godwin AK, Weaver J, Kim WE.
Breast Cancer Res. 2012 Feb 8;14(1):R26.

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