By Clinical Research News Staff 

July 15, 2025 | A fragmentation-based blood test is providing pharmaceutical companies with a new way to monitor cancer treatment response in clinical trials, informing how drug efficacy is evaluated in early-stage development. 

Delfi Diagnostics has developed DELFI-TF (DELFI-tumor fraction), a research-grade assay that uses a unique fragmentation approach to detect circulating tumor DNA in blood samples. Unlike traditional mutation-based testing, this method can monitor treatment response and disease progression without requiring knowledge of specific tumor mutations. 

The technology addresses a longstanding problem in oncology clinical trials: determining early whether experimental treatments are working. "The biggest risk of failure is lack of efficacy, and monitoring tests [like DELFI-TF] basically give us an early look at [that]," explains Nicholas Dracopoli, Ph.D., Delfi's chief scientific officer and co-founder. 

Practical Advantages for Clinical Trials 

The assay offers several key benefits for clinical trial applications. DELFI-TF requires only 800 microliters of plasma compared to 2-4 milliliters needed for mutation testing—a significant advantage in early-phase trials where blood draw requirements are already extensive for pharmacokinetic analyses. The test can be deployed across all patients and studies at a much lower cost than mutation-based assays, making comprehensive monitoring feasible for pharmaceutical companies. And the assay can deliver results within two weeks, crucial for dose escalation studies where timely data drives decision-making. 

Delfi has established partnerships with numerous global pharmaceutical companies, particularly for immunotherapy development where ideal treatment response markers are currently lacking. The company announced a collaboration with Immunocore to explore DELFI-TF as an early predictor of benefit from novel bispecific T cell receptor immunotherapies. 

Early Detection of Treatment Effects 

One of the most compelling aspects of DELFI-TF is its ability to detect molecular response evidence months before clinical effects become apparent through traditional tumor size assessments. Changes in circulating tumor burden can be detected within weeks of therapy initiation, even at very low doses. 

Since not everything can advance to clinical trials, “early evidence of molecular response in early drug development is gold," Dracopoli says. "It's a level of information that helps you risk-adjust how you develop these compounds." 

The technology originated from research at Johns Hopkins and uses machine learning to analyze DNA fragmentation patterns in blood, allowing researchers to differentiate between tumor-derived DNA and normal circulating DNA from white blood cells. 

For the complete story about Delfi's fragmentation technology, including details about their screening applications and the scientific foundation of their approach, read Deborah Borfitz’s full article at Diagnostics World.