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 personalised based on the unique DNA of a patient’s tumour.

The study results, published in the January 8, 2026 online edition of Journal of Clinical Oncology found that individualising multi-drug treatments to each patient’s specific tumour 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 tumour’s distinctive DNA, we can treat cancer with better accuracy.”

The clinical trial, known as Investigation of Profile-Related Evidence Determining Individualised Cancer Therapy (I-PREDICT), used advanced genomic sequencing to identify the genomic changes driving each person’s cancer.

Clinicians then developed personalised 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 tumour 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 tumour 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 Centre,” said Diane Simeone, MD, director of Moores Cancer Centre 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 centre of every decision.”

Both Sicklick and Kato are members of UC San Diego Moores Cancer Centre, which served as a key partner in supporting the clinical trial.

Moores Cancer Centre at UC San Diego Health is the region’s only National Cancer Institute (NCI)-designated Comprehensive Cancer Centre.

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 programme at Moores Cancer Centre, 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 analysed 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 organisations can replicate precision cancer care strategies.

This study lays the groundwork for a future randomised trial designed to confirm the benefits of this personalised precision oncology approach.

Source: University of California - San Diego