Summary: A new radiotracer, 99mTc-p5+14, can detect cardiac amyloidosis early, producing high-quality images and significant uptake in patients, with potential for widespread use and upcoming Phase 3 trials.

Key Takeaways:

  1. The new radiotracer 99mTc-p5+14 produces high-quality images for detecting cardiac amyloidosis, potentially crucial for early diagnosis and treatment.
  2. Cardiac amyloidosis remains a severe, incurable disease with low median survival rates, highlighting the need for early detection technologies.
  3. The radiotracer 99mTc-p5+14 is undergoing early-stage clinical evaluation, with promising results leading to upcoming Phase 3 trials and future FDA approval submissions.

A new radiotracer, 99mTc-p5+14 , can produce high-quality images of cardiac amyloidosis, known as the “Alzheimer’s of the heart.” As the first amyloid-specific radiotracer for planar and SPECT/CT imaging, it could be crucial for early detection and treatment. This research was presented at the 2024 Society of Nuclear Medicine and Molecular Imaging Annual Meeting.

Systemic Amyloidosis

Systemic amyloidosis is an incurable disease in which abnormal amounts of proteins build up within the body’s tissues and organs. About 20 percent of patients who have amyloid build-up in the heart experience early deaths. While recent progress in the treatment of cardiac amyloidosis has greatly improved patient prognosis, median survival remains low at approximately three to five years.

“Therapies that slow the progression of amyloid deposition have been developed; however, they are not effective in patients with late-stage disease. Therefore, the ability to detect cardiac amyloidosis early is critical,” says Jonathan Wall, PhD, director of the Amyloidosis and Cancer Theranostics Program and professor at the University of Tennessee Graduate School of Medicine in Knoxville. “Unfortunately, there are currently no FDA-approved imaging agents that detect cardiac amyloidosis.”

99mTc-p5+14 Promising for Amyloidosis Imaging

To address this issue, researchers developed a novel technetium-99m labeled variant of the pan-amyloid reactive peptide p5+14 (99mTc-p5+14). In the first-in-human study, five healthy volunteers and 30 patients newly diagnosed with light chain or transthyretin amyloidosis underwent 99mTc-p5+14 imaging with standard planar gamma scintigraphy and SPECT/CT. Blood was collected to assess serum biomarkers, and a transthoracic echocardiogram was performed. Standard 99mTc-pyrophosphate imaging was also performed on most patients at 72 hours after 99mTc-p5+14 image acquisition.

The planar and SPECT/CT images generated using 99mTc-p5+14 were of high quality and readily interpretable at both one and three hours post-injection. Patients with amyloid cardiomyopathy had significant 99mTc-p5+14 uptake in the heart, whereas no cardiac uptake was observed in healthy subjects.

“Early and accurate diagnosis of cardiac amyloidosis is crucial to ensure the most positive outcomes for patients,” says Wall. “Imaging with 99mTc-p5+14 could provide an easy to use and interpret technology that could be employed in the community cardiology setting, where SPECT imaging is common, as a rapid screen for amyloid cardiomyopathy in the future.”

Early Clinical Trials for Safety and Efficacy

The 99mTc-p5+14 radiotracer is currently in ongoing early-stage clinical evaluation at the University of Tennessee Graduate School of Medicine in conjunction with Attralus Inc., to assess safety and efficacy in patients with cardiac amyloidosis and healthy subjects. The data and insights obtained from this research will support initiation of a pivotal Phase 3 study and approval submissions to the FDA in the coming years.