Researchers at University of California San Diego School of Medicine have led the first clinical trial in the world to show that cancer drug treatments can be safely and effectively personalized based on the unique DNA of a patient's tumor.
The study results, published in the January 8, 2026 online edition of Journal of Clinical Oncology found that individualizing multi-drug treatments to each patient's specific tumor mutations using molecular testing can significantly enhance treatment success.
"Every patient and every cancer is unique, and so should how we treat for them," said Jason Sicklick, MD, senior author of the study, professor of surgery and pharmacology at UC San Diego School of Medicine and surgical oncologist at UC San Diego Health. "Our findings demonstrate that precision oncology at the individual level is achievable. When every patient's treatment is guided by their tumor's distinctive DNA, we can treat cancer with better accuracy."
The clinical trial, known as Investigation of Profile-Related Evidence Determining Individualized Cancer Therapy (I-PREDICT), used advanced genomic sequencing to identify the genomic changes driving each person's cancer. Clinicians then developed personalized treatment plans using FDA-approved drugs, with doses carefully adjusted for each patient to precisely target those molecular alterations — the opposite of a one-size-fits-all approach.
Among a cohort of 210 patients with advanced cancers that were treated, nearly 95% had distinct tumor DNA profiles — no two cancers were alike. This led to 157 different treatment regimens, including 103 new drug pairings that had never been tested together before. Patients whose therapies were most closely matched to their tumor mutations experienced better treatment results, improving their chances for response and survival. Importantly, those who received new drug combinations did not experience more severe side effects than patients receiving standard therapies.
The study also found that starting new drug mixes at lower doses and carefully increasing them over time kept treatments safe, even with therapies that had never been used together before.
"The I-PREDICT study shows what's possible when we let a patient's biology guide their treatment," said Shumei Kato, MD, associate professor of medicine at UC San Diego School of Medicine and medical oncologist at UC San Diego Health. "By using biomarkers to select drugs and adjust doses, we can design combinations that precisely target the drivers of each person's cancer."
"Innovative clinical trial design is a central part of what we do at Moores Cancer Center," said Diane Simeone, MD, director of Moores Cancer Center at UC San Diego Health. "This study reflects the strength of our multi-disciplinary team-based approach, combining scientific leadership, clinical trial expertise and the infrastructure needed to bring discoveries directly to patients. It's a powerful example of how we're shaping the future of precision oncology and placing the patient at the center of every decision."
Both Sicklick and Kato are members of UC San Diego Moores Cancer Center , which served as a key partner in supporting the clinical trial.
Moores Cancer Center at UC San Diego Health is the region's only National Cancer Institute (NCI)-designated Comprehensive Cancer Center. They are consistently ranked among the top 50 in the nation for cancer care by U.S. News & World Report.
Sicklick, who is also co-leader of the structural and functional genomics program at Moores Cancer Center , adds that this research marks a turning point for cancer treatment.
"Instead of a one-size-fits-all, we're moving toward one-size-fits-one," said Sicklick.
The research builds upon earlier findings published in Nature Medicine (2019) and Genome Medicine (2022) that analyzed subsets of the I-PREDICT cohort. The new publication expands this work, including more patients and longer follow-up, while offering detailed guidance on how other organizations can replicate precision cancer care strategies.
This study lays the groundwork for a future randomized trial designed to confirm the benefits of this personalized precision oncology approach.
Additional co-authors of the study include Daisuke Nishizaki, Hirotaka Miyashita, Ryosuke Okamura, Michael E. Hahn, Mina Nikanjam, Paul T. Fanta, David E. Piccioni, Hitendra Patel, Ramez N. Eskander, Rana R. McKay, Jeffrey S. Ross, J. Jack Lee, Scott M. Lippman, Shumei Kato, and Razelle Kurzrock, MD, all at UC San Diego.
Funding support for the study came, in part, from Foundation Medicine, the Joan and Irwin Jacobs Foundation, Jon Strong, and the National Institutes of Health (P30 CA023100).
