New radiotracer safe and effective for imaging early rheumatoid arthritis

Inflammation is a significant part of several chronic diseases, including rheumatoid arthritis and its related issues. While PET imaging with 18F-FDG is a valuable tool for the diagnosis and monitoring of the effects of treatments, it is not specific enough to assess inflammation.

"It's important to detect inflammation early so that patients can receive the best treatment," said Anne Roivainen, PhD, professor of preclinical imaging and drug research at Turku PET Centre at the University of Turku and Turku University Hospital in Finland. "Our institution has worked for several years to develop an imaging agent that targets areas of inflammation, and in this study, tested its effectiveness in humans for the first time."

To evaluate the radiotracer's safety and biodistribution characteristics, six healthy study participants underwent whole body 68Ga-DOTA-Siglec-9 PET/computed tomography scans. 68Ga-DOTA-Siglec-9 was well-tolerated and cleared quickly from the blood, and its radiation dose was similar to other 68Ga tracers. In one additional study participant with rheumatoid arthritis, the tracer was able to clearly detect joints with arthritis.

"We have proven that the characteristics of 68Ga-DOTA-Siglec-9 are favorable for use in patient imaging studies," remarked Roivainen. "Future studies will clarify whether 68Ga-DOTA-Siglec-9 PET imaging has the potential to detect other inflammatory diseases early. It could also help to evaluate the effectiveness of treatments and promptly identify patients who are unlikely respond to therapy."

This study was made available online in August 2020 ahead of final publication in print in April 2021.