A new study published in Transplantation Direct has validated the long-term clinical utility of Oncocyte Corporation's proprietary blood-based transplant rejection assay, demonstrating its effectiveness in identifying organ rejection in kidney transplant patients up to 13.7 years after transplantation.
The observational study, conducted at Charité University in Berlin, analyzed data from 131 patients with 151 kidney biopsies collected over four years. The research was co-authored by Oncocyte's Drs. Ekke Schuetz and Julia Beck, who are the original inventors of the technology.
"There are only a few publications on the dynamics of dd-cfDNA in other common pathologies beyond rejection," said Dr. Schuetz, Oncocyte's Chief Science Officer. "Our study aimed to assess both the absolute and relative values of dd-cfDNA in diverse histopathological patterns, the correlation of dd-cfDNA with Banff lesion scores, and the recently suggested Banff-based activity and chronicity indices in consecutive cases of kidney transplant recipients undergoing indication biopsies."
Key Scientific Findings
The study revealed a correlation between microvascular and vascular inflammation and elevated donor-derived cell-free DNA (dd-cfDNA) in blood plasma, contributing to a broader understanding of transplant rejection pathophysiology.
Two novel observations emerged from the research:
- T-cell mediated rejection (TCMR) is associated with high elevation of dd-cfDNA when vascular inflammation is present
- Calcineurin inhibitor toxicity (a common side effect of immunosuppressive medications) does not lead to increased dd-cfDNA levels
These findings suggest that dd-cfDNA serves as a relatively specific biomarker for both antibody-mediated rejection (ABMR) and T-cell mediated rejection with vascular inflammation. Researchers are currently investigating why certain patients with BK virus infection also show elevated dd-cfDNA levels.
Strategic Implications for Patient Care
The study builds upon the scientific foundation supporting long-term management of high-risk transplant patients using Oncocyte's proprietary test. Notably, patients in the study ranged from 1.6 to 13.7 years post-transplant, demonstrating the assay's continued utility more than a decade after transplantation.
A significant percentage of patients with confirmed organ rejection also had de novo donor-specific antibodies (dnDSA+) in their blood. These high-risk patients are the same population Oncocyte identified in its 2024 prospective, randomized clinical trial, which led to expanded Medicare reimbursement coverage for claims in 2025.
"Data from this study reinforces that doctors should be routinely screening these high-risk patients with our test," said Josh Riggs, Oncocyte CEO. "Kidney transplant management is changing. Anti-CD38 therapies have a chance at treating transplant rejection. Assuming the data continue to be supportive, catching transplant rejection as early as possible becomes critical."
Commercialization Progress
Oncocyte is currently at a pivotal stage in commercializing what it describes as a potentially industry-transforming organ transplant rejection monitoring test. The company aims to deliver proven, more affordable, and faster tests that can be run at local laboratories.
Specifically, Oncocyte is developing a kitted test that quantifies dd-cfDNA and plans to commercialize the technology using what it calls a "market disruptive approach." In addition to the kitted version under development, Oncocyte already offers a dd-cfDNA detection assay at its Nashville laboratory, which achieved Medicare reimbursement in August 2023.
"This latest publication comes from a long-standing research and collaborative relationship that we have with Charité University in Berlin, one of the leading research universities in the world," Riggs added. "As they continue to advance the field's scientific knowledge about transplantation, we are proud that our assay is being used to understand the fundamental biology at play in transplanted organ rejection."
Study Details
The full study, titled "Association of Blood Donor-derived Cell-free DNA Levels With Banff Scores and Histopathological Lesions in Kidney Allograft Biopsies: Results From an Observational Study," was published in the May 2025 issue of Transplantation Direct.
The research represents a significant advancement in understanding transplant rejection biology and supports the expanded use of non-invasive blood tests for monitoring transplant patients, potentially reducing the need for invasive biopsies while improving long-term outcomes through earlier detection of rejection.
Oncocyte describes itself as a pioneering diagnostics technology company with a mission to democratize access to novel molecular diagnostic testing to improve patient outcomes.
