A meta-analysis of 346 phase I clinical trials involving more than 13,000 patients found that patients whose treatment was selected based on the molecular characteristics of their tumour had significantly better outcomes.

The study, here, was featured in a press briefing this week and will be presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.

“Our study suggests that, with a precision medicine approach, we can use a patient’s individual tumour biomarkers to determine whether they are likely to benefit from a particular therapy, even when that therapy is at the earliest stage of clinical development,” said lead study author Maria Schwaederle, PharmD, of the Center for Personalised Cancer Therapy, University of California-San Diego School of Medicine. “This strategy often results in good outcomes for patients, and I hope it will encourage and reassure doctors and patients considering enrollment in precision medicine-based phase I trials.”

Previous meta-analyses of phase II and phase III trials by the same researchers observed similarly improved outcomes with precision medicine approaches. 

According to the authors, this is the first study to show that such benefits are apparent even at the first stage of clinical development.

It suggests that tumour biomarkers should be increasingly used to select patients for phase I clinical trials.

“Precision medicine is not the future of cancer care, it is the present. This study reinforces that the more we personalize treatment to the patient and the tumour, the better the outcomes – even in the earliest phases of research,” said Don S. Dizon, MD, FACP, ASCO spokesperson and moderator of the presscast. “This is the same approach ASCO’s TAPUR trial is using, and we anticipate it will also bring new insights that lead to better therapies for patients in need.”

The study examined efficacy and safety data from 346 phase I trials published between 2011 and 2013.

The analysis included 58 treatment arms that employed precision medicine – defined as using biomarkers to select patients for treatment – and 293 that did not (all but one of these precision medicine trials evaluated a targeted agent: the trial evaluated the chemotherapy drug topotecan, which is believed to inhibit hypoxia-inducible factor 1-alpha (HIF-1 alpha), and patients in that trial were tested for this marker).

The researchers found that in treatment arms employing precision medicine, tumour shrinkage rates were 30.6%, compared to 4.9% in those that did not.

Patients in precision medicine arms also had a longer time before the disease worsened (progression-free survival) compared to other arms (median 5.7 months vs. 2.95 months).

Results were similar in a sub-analysis that included 57 trials of targeted therapies – drugs that target specific genes or proteins found in cancer cells.

In this group, treatment arms using biomarkers to assign patients to treatments had tumour shrinkage rates of 31.1%, compared to 5.1% for those that did not.

Additionally, researchers found that matching patients to therapy based on genomic (DNA) biomarkers resulted in higher tumour shrinkage rates (42%) compared to protein biomarkers (22.4%).

In this analysis, the high tumour shrinkage rates and prolonged time to disease progression observed with precision medicine approaches suggest that phase I studies, which have traditionally focused on safety, can also provide important insights into efficacy and the patients likely to benefit most. 

Incorporating survival endpoints into phase I trials may help accelerate development of important new therapies, the authors suggested.

Source: ASCO 2016