PET/CT with new agent proves safe, successful in targeted breast imaging

HER2-positive breast-cancer patients are safely and effectively imaged with PET/CT after being infused with a solution based on the radiotracer pertuzumab, according to a study published online Nov. 16 in the Journal of Nuclear Medicine.

Gary Ulaner, MD, PhD, of Weill Cornell and colleagues conjugated pertuzumab with the drug deferoxamine and radiolabeled it with the positron-emitting isotope 89Zr.

They administered the Zr-DFO-pertuzumab to six patients with HER2-positive metastatic breast cancer, then scanned them with PET/CT and performed whole-body probe counts and blood draws over eight days.

The team found PET/CT offered optimal imaging five to eight days following the radiotracer administration, and the results showed its ability to image HER2-positive malignancy in multiple sites.

In fact, in two patients with both known HER2-positive and HER2-negative primary breast cancers and brain metastases, the pertuzumab solution enabled the researchers to distinguish the brain metastases as HER2-positive.

No patients had adverse reactions, the authors report.

“This first-in-human study demonstrated safety, dosimetry, biodistribution and successful HER2-targeted imaging with 89Zr-pertuzumab PET/CT,” Ulaner et al. write. “Potential clinical applications include assessment of HER2 status of lesions which may not be accessible to biopsy and assessment of HER2 heterogeneity.”