PET Radiotracer Gets FDA Breakthrough Therapy Designation for Tumor Hypoxia Detection in HPV-Positive Oropharyngeal Carcinoma

The Food and Drug Administration (FDA) has granted a breakthrough therapy designation for the positron emission tomography (PET) radiotracer JBS-003 (¹⁸F-fluoromisonidazole or F-MISO) for detecting tumor hypoxia in patients with HPV-positive oropharyngeal carcinoma (OPC).¹

Noting that current radiation therapy regimens for HPV-positive OPC often lead to osteoradionecrosis and long-term impacts on quality of life, Juniper Biosciences, the developer of JBS-003, said the agent’s detection of tumor hypoxia may facilitate more targeted treatment and a potentially greater than 50 percent reduction in ionizing radiation dose.

“This (FDA) designation is a powerful validation of what precision imaging can do for these patients. Using F-MISO PET imaging, we can visualize the specific hypoxic signatures of a tumor to maintain aggressive control where it’s needed, while safely reducing radiation doses for patients with well-oxygenated tissue. The FDA has now recognized that this approach may represent a substantial improvement over the current standard of care,” noted Alex Agnoletto, the CEO of Juniper Biosciences.

In a 2024 study involving 123 patients with HPV-positive OPC, researchers found that after initial instruction on the use of JBS-003 for PET/CT scans, there was 77.3 percent sensitivity and 80.9 percent specificity for visual assessment of tumor hypoxia. Subsequent quantitative assessments after dedicated training on JBS-003 revealed mean sensitivity and specificity of 89.6 percent and 95.3 percent respectively, according to the study.²

Juniper Biosciences noted that JBS-003 is currently being evaluated in a randomized, double-blind phase 3 trial for guiding de-escalated radiation therapy in patients with HPV-positive OPC.

(Editor’s note: For related content, see “SNMMI: AI May Enhance Detection and Risk Assessment for Multiple Cancers on Whole-Body PET/CT Scans,” “Study Shows 45 Percent Increase in Emergency Department Neuroimaging Over the Last Decade” and “FDA Clears MRI-Based AI Segmentation of Organs at Risk During Radiation Therapy.”)

References

1. Juniper Biosciences. Juniper’s JBS-003 (F-MISO) program receives FDA breakthrough therapy designation, advancing a first-in-class hypoxia tracer enabling radiation de-escalation in HPV-positive head and neck cancer. GlobeNewswire. Available at: https://www.globenewswire.com/news-release/2026/09/01/3354282/0/en/juniper-s-jbs-003-f-miso-program-receives-fda-breakthrough-therapy-designation-advancing-a-first-in-class-hypoxia-tracer-enabling-radiation-de-escalation-in-hpv-positive-head-and-n.html . Published September 1, 2026. Accessed September 3, 2026.

2. Wray R, Mauguen A, Michaud L, et al. Development of ¹⁸F-fluoromisonidazole hypoxia PET/CT diagnostic interpretation criteria and validation of interreader reliability, reproducibility and performance. J Nucl Med. 2024;65(10):1526-1532.