The Molecular Imaging Biomarker Research Group of Siemens Medical Solutions USA has completed a Phase II multicenter clinical trial of its HX4 positron PET imaging biomarker, which is designed to detect hypoxia—a reduction in tissue oxygen levels—in solid tumors.
The trial’s primary objective was to test the reproducibility of HX4’s uptake in tumors by conducting PET/CT scans of the same patient on sequential days in a test-retest protocol. The trial enrolled 40 patients with head and neck, lung, liver, rectal or cervical cancers, who were scheduled to receive chemotherapy, radiation therapy or a combination of the two.
Solid tumor hypoxia develops when the vascular system is unable to supply the growing tumor mass with adequate oxygen, leaving portions of the tumor with lower oxygen levels than healthy tissues. Hypoxic tumors are more resistant to radiotherapy and chemotherapy, resulting in overall poor outcomes. By developing an imaging biomarker that detects tumor hypoxia, Siemens hopes to provide oncologists with more specific information regarding tumor cells that can be used in the fight against cancer.