Epic Sciences, Inc. and its research partners today report the use of the company’s new circulating tumor cell (CTC) homologous recombination deficiency (HRD) liquid biopsy assay for the prediction of drug resistance in patients with metastatic castration-resistant prostate cancer (mCRPC). The assay is being utilized as a selection device in BeiGene, Ltd.’s ongoing Phase 2 clinical trial with its investigational PARP inhibitor (pamiparib) in this patient population (NCT03712930).
The Epic Sciences CTC HRD assay measures chromosomal instability within circulating tumor cells in the blood of patients with cancer by identifying distinct cell morphology feature sets. Chromosomal instability, a hallmark of aggressive cancer, has also been associated with DNA Damage Repair (DDR) deficiency. PARP inhibitors have been shown to be an effective therapeutic in the treatment of cancers characterized by chromosomal instability by targeting DNA repair pathways in cells with DDR deficiency. However, it has been very difficult to measure chromosomal instability from tumor biopsy due to under sampling and heterogeneity, problems designed to be addressed by Epic’s liquid biopsy approach.
“This is the first assay to measure chromosomal instability using circulating tumor cells and digital pathology, opening up tremendous opportunities for developers of anticancer PARP inhibitors to improve patient selection in clinical trials,” said Ryan Dittamore, Chief of Medical Innovation at Epic Sciences and co-author of a clinical validation study presented at the 2019 American Society of Clinical Oncology Genitourinary Cancers Symposium (ASCO-GU). “The ability to track this key mechanism of cancer progression within patients through a simple blood draw not only predicts when patients won’t respond to standard of care therapy, but also who should consider therapies that target DNA repair pathways, ultimately helping facilitate better therapeutic selection for a high-risk group of mCRPC patients. Now drug developers can identify more patients faster, than the use of BRCA mutational analysis alone.”
“We are excited to be at the forefront of the development of this novel CTC HRD assay with our global Phase 2 trial of pamiparib in patients with metastatic castration-resistant prostate cancer,” said Mitch Raponi, Vice President, Biomarker Development & Translational Research at BeiGene. “Identifying patients with homologous recombination deficiency is challenging in this patient population using standard sequencing techniques. As we enroll patients in this trial, we anticipate that this microscopy-based circulating tumor cell detection technology will enable the identification of more patients whose tumors exhibit bona fide HRD, with the potential for a greater likelihood of clinical response to PARP inhibition.”
Epic Sciences is involved in several additional studies to further validate the clinical utility of the CTC HRD assay using its Functional Cell Profiling (FCP) platform technology. As more therapies from different drug classes are developed and approved for prostate and other cancers, Epic Sciences plans to expand its portfolio of tests that provide high-value information to oncologists and patients to identify their best treatment options.
Epic demonstrated its expertise in the development of blood-based tests that predict therapy response with the launch of the Oncotype Dx© AR-V7 Nucleus Detect™ test that is now commercially available and reimbursed by Medicare. The test, which is offered in the U.S. through Epic’s partnership with Genomic Health for patients with mCRPC, assists physicians in choosing between androgen receptor-directed therapies or chemotherapy.
Source – Epic Sciences