On December 17, 2025 Personalis, Inc. (Nasdaq: PSNL), a leader in advanced genomics for precision oncology, reported the publication of a new study in Clinical Cancer Research, a journal of the American Association for Cancer Research (AACR) (Free AACR Whitepaper). The paper, titled "Broad Utility of Ultrasensitive Analysis of ctDNA Dynamics across Solid Tumors Treated with Immunotherapy," details results from Dr. Rodrigo Toledo and a leading team at the Vall d’Hebron Institute of Oncology (VHIO) in Barcelona, Spain. The study provides compelling clinical evidence that the company’s ultra-sensitive, tumor-informed molecular residual disease (MRD) assay, NeXT Personal, can effectively predict patient outcomes across a diverse set of cancers and immunotherapy modalities.
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The study analyzed 202 patients with stage IV solid tumors—spanning 24 different cancer types—treated with immune checkpoint inhibitors and other immunotherapies. Utilizing a personalized testing approach that tracks up to ~1,800 tumor-specific variants unique to each patient’s tumor, the NeXT Personal test achieves ultrasensitive detection of small traces of circulating tumor DNA (ctDNA) from a patient’s blood sample.
Key findings published in Clinical Cancer Research include:
High Sensitivity: The test detected ctDNA in 98% of patients at baseline across all 24 tumor types, demonstrating robust performance even in a diverse set of cancers.
Early ctDNA Dynamics are Highly Prognostic: Patients who demonstrated decreases in ctDNA levels early in immunotherapy treatment had significantly higher overall survival. Conversely, patients with increasing ctDNA levels early while on immunotherapy had a zero percent overall response rate.
Durable ctDNA Clearance was a Positive Predictor: Patients who achieved durable molecular clearance (negative ctDNA for at least 180 days) had 100% overall survival (OS) in the study.
"We are excited about these results showing how NeXT Personal can be used to monitor therapy in late-stage metastatic patients," said Rich Chen, M.D., M.S., Chief Medical Officer and Executive Vice President, R&D at Personalis. "This study, together with our previous publications, shows the broad potential impact of ultrasensitive ctDNA testing, both in early and late stage cancers."
Dr. Rodrigo Toledo, Group Leader of the Biomarkers and Clonal Dynamics Laboratory at VHIO and senior author of the study, noted, "immunotherapy has revolutionized cancer care, but response patterns can be difficult to interpret using imaging alone. Our findings show that ultrasensitive ctDNA dynamics provide a clear, early molecular view of benefit or non-response, offering a powerful tool to guide patient management across a broad spectrum of solid tumors."
(Press release, Personalis, DEC 17, 2025, View Source [SID1234661515])