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Updated Definition Of ‘Clinical Utility’ Could Foster Adoption Of Genetic Testing

By Deborah Borfitz 

August 24, 2022 | WASHINGTON—The clinical utility of genetic testing has been newly redefined to reflect the realities of modern cancer care, according to Daryl Pritchard, senior vice president of science policy for the Personalized Medicine Coalition, during his keynote presentation at this week’s Next Generation Dx Summit in Washington, D.C. The education, advocacy, and evidence-developing organization championed efforts to pen the update through a roundtable event sponsored by Genentech. 

Stakeholders from the bench to the bedside—researchers, regulators, payers, and providers—are involved in the development of personalized medicine. But its clinical implementation depends on the balance of benefits to risks that payers and providers care about, says Pritchard. 

This differentiates clinical utility from analytic validity, which refers to how well a test predicts a diagnosis or presence of a disease biomarker, and clinical validity, which describes how well a biomarker relates to a disease or affects a health condition. Clinical utility is “information about the diagnosis, treatment, and management of disease that provides value to the healthcare system,” Pritchard says. 

It is widely acknowledged that genetic testing continues to be underutilized in oncology despite ample evidence that it confers enormous benefit, he continues. A 2019 study by the Fred Hutchinson Cancer Research Center found that, relative to single gene test for non-small cell lung cancer (NSCLC), multigene panel sequencing increased the identification of actionable mutations from 23% to over 30%. 

Newer biomarkers, including tumor mutation burden, have increased the detection rate to over 70% since then, adds Pritchard. Still, only 8 to 10% of cancer patients are getting genetic testing. 

The most often cited description of the clinical utility of genetic testing up until now appeared in a 2006 Genetics in Medicine paper (DOI: 10.1097/01.gim.0000227935.26763.c6), he says. But that wording neither accounts for more recently introduced technologies that have “changed the paradigm” nor addresses utilization related to cancer and oncology.  

A group of experts (labs, providers, patients, payers, representatives from diagnostic and therapeutic companies, and guideline developers) was therefore convened at the end of 2019 to implement a new definition (JCO Precision Oncology, DOI: 10.1200/PO.21.00349) that expanded beyond the purposes originally identified, Pritchard says. Genetic testing was defined, specifically its benefit to cancer patients and the health system, in terms of not only improving outcomes but also enhancing shared decision-making and reducing healthcare disparities.   

The roundtable discussion reframed the definition to consider multiplex tests for a broader range of purposes and factors associated with clinical utility having different magnitudes of impact depending on the stakeholder, he explains. These include the health system and population benefit associated with data compilation and more efficient sample processing and patient access to additional preventive and treatment strategies—as well clinical trial eligibility assessment or enrollment, which is most important to patients. Moreover, the definition encompasses opportunities for longer, more candid patient-provider dialogue about what constitutes best treatment. 

Adoption Hurdles 

Creation of the new definition for clinical utility does not ensure it will be recognized and employed, Pritchard points out. 

Maximizing the usefulness of genetic testing in cancer care will require that physicians understand current developments, since biomarkers are rapidly evolving, and that testing processes are consistent, standardized, and validated, he continues. Pritchard additionally mentions the deployment of evidence-based clinical decision support via guidelines and pathways, ensuring access to targeted treatments, and guiding patients to the appropriate clinical trials when applicable.    

In the Q&A that followed his presentation, Pritchard shared that reimbursement, and thus access to testing, is a key concern of many stakeholders. Payers don’t yet recognize the utility of the multiplex genetic testing strategy to answer multiple questions at the same time, he says. 

Among the issues being addressed are improving utilization of established diagnostic markers as well as awareness of newly approved markers and those under development in clinical trials. In NSCLC, for example, multiple targeted therapies are available but currently patients are being tested only for three markers, says Pritchard.  

As it stands, genetic testing tends to be unaffordable without grant support. It is hoped that the updated clinical utility definition, which applies to both laboratory developed tests and traditional in vitro diagnostics, will help payers see the value of genetic testing and make it more accessible at the community health level, Pritchard says. Medicare is already covering genetic testing for people with NSCLC, he adds. 

For advanced cancers anyway, reflex genetic testing (part of standard pathology review protocols) tends to be the favored approach, Pritchard says. But even here, some say genetic testing is being done unnecessarily on patients who won’t gain any benefit from it, so the evidence-building process continues.


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