Glenn J. Hanna, MD, Director, Center for Cancer Therapeutic Innovation (Early Drug Development Program), medical oncologist at the Center for Head & Neck Oncology at Dana-Farber Cancer Institute, and Associate Professor of Medicine, Harvard Medical School, Boston, was interviewed for his thoughts on the pilot study by Memorial Sloan Kettering Cancer Center (MSK) investigators.

Dr. Hanna explained that the tumor-tissue–modified viral human papillomavirus (HPV) DNA test, the NavDx assay, searches for the sequences of DNA associated with high-risk HPV that are attributable to or associated with an HPV-positive tumor. “HPV-positive cancers can shed HPV DNA into the bloodstream in some capacity, and you can monitor those specific DNA sequences,” he said.

Glenn J. Hanna, MD

How Best to Use This Assay

Focusing on the pilot study conducted at MSK, he questioned the design of the study, which allowed participants to forgo standard adjuvant radiotherapy if their HPV DNA cleared. As the investigators reported, the 25% rate of recurrence was high, he noted, and of special interest was the false-negative test in one patient who experienced radiographic disease progression.

“There is no perfect test, and one false-negative in a postop pilot trial setting, to me, is not something that should degrade the broader utility of the assay…. It may be that the assay is not as reliable in that setting,” Dr. Hanna commented. The HPV ctDNA assay is probably better suited for identifying early occult recurrences in patients after treatment or during surveillance, he maintained. Such blood-based monitoring is fast becoming established in other malignancies and is supported in oropharyngeal cancer as well by a growing body of data. “The data overwhelmingly suggest that HPV ctDNA is very useful in patients who have completed therapy, where you’re using the assay to monitor for residual disease in the long-term follow-up setting,” he said. 

DISCLOSURE: Dr. Hanna has received research support from ACCRF, Actuate, Elevar, Gateway for Cancer Research, Genentech, Remix, and Kura Oncology; and has served as a consultant or advisor for Elevar, Kura Oncology, Prelude, Remix, and Naveris (the company that developed the NavDx assay used in this pilot study).