|Articles|December 6, 2016

Top barriers to fully utilizing precision medicine biomarkers

As development of molecular biomarkers hastens, administrators, clinicians and regulators are working to organize and define biomarkers’ appropriate roles in clinical care-and discussing how to efficiently share the massive amounts of genomic data that will result.

Diagnostic, predictive, and prognostic molecular and genomic biomarkers are the cornerstone of personalized medicine. These assays can range from tests for individual proteins or gene mutations associated with disease aggressivity or probable treatment outcomes, to panels and even whole-genome tests.

A bewildering array of these molecular tests is in development but laboratories, administrators, providers, and regulators are still working out how best to validate these tools and bring them into clinical practice to improve patient care.

One crucial challenge will be implementing systems to share massive amounts of genomic testing data in national repositories, researchers said at a special education session on precision medicine on December 5 at the at the 58th American Society of Hematology (ASH) Annual Meeting in San Diego.

Lyman“Precision medicine certainly got a great deal of public attention two years ago when President Obama announced the Precision Medicine Initiative,” said Panel Chairman Gary Lyman, MD, MPH, of the Fred Hutchinson Cancer Research Center in Seattle.

Much of the attention since Obama’s announcement has been focused on the hope and promise of biomarkers, Lyman said.

“Excitement’s been building with exponential improvements in our understanding of human and cancer genomes, and molecular targeting agents,” he said. “There are many opportunities stemming from our identification of multiple molecular targets, particularly in clinical oncology across various cancer types-including hematologic malignancies.”

Significant hurdles

But there are significant technical, clinical, and institutional hurdles, as well-and these have not been as widely appreciated.

“There are many challenges, ranging from establishing the analytic validity of tests we use and demonstrating that they actually measure what we say they measure, and that these assays’ results correlate with specific clinical outcomes, and ultimately, to demonstrate that the tests can change or improve clinical outcomes or improve clinical decision making in ways known to affect clinical outcomes-what we call ‘clinical utility,’” Lyman said.

Hematological cancers are “part and parcel” of this discussion, he added. “Chronic myeloid leukemia is the poster child of precision medicine. A number of targeted therapies have been introduced over the past few years, particularly targeting B cell receptors’ signaling pathways and identifying new agents.”

“We face challenges in how to bring all of these increased understandings down to the individual patient,” Lyman said.

One problem has been that most proposed biomarkers have low-level evidence in their favor, such as retrospective observational studies.

“We’re having prospective studies based on cohorts and registries and we’re looking forward to higher-level evidence from prospective randomized trials driven by biomarker results,” he said.

As better-designed studies become the norm, researchers will spend less time on candidate biomarkers that turn out not to be useful. “The role of pure chance or bias is being driven out,” he said.

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