Lutroo Imaging Initiates First-in-Human Trial of Radiocaine™ PET Tracer for Pain Visualization

Lutroo Imaging (search)Search term has officially launched a Phase 1 clinical trial of Radiocaine (search)Search drug™, marking the first time a PET radiotracer specifically designed to visualize pain has been tested in human subjects. The clinical-stage molecular imaging company announced that the first subject has been dosed in this groundbreaking study, which aims to revolutionize pain diagnosis and treatment.

Addressing a Critical Unmet Medical Need

The development of Radiocaine (search)Search drug™ addresses a massive gap in pain medicine: over 50 million adults in the U.S. live with chronic pain, yet clinicians currently have no tools to objectively visualize it. "There's a critical need to move beyond guesswork in diagnosing pain," said Dr. Braxton Norwood, CEO of Lutroo Imaging (search)Search term. "Radiocaine™ has the potential to not only localize and quantify pain, but also to act as a biomarker in clinical trials, helping us measure whether therapies are working, objectively."

The ongoing opioid crisis underscores the urgency of developing safer, more targeted approaches to pain management, beginning with the ability to accurately detect and measure pain.

Novel Mechanism and Technology

Radiocaine (search)Search drug™ is a fluorine-18-labeled PET radiotracer designed to bind voltage-gated sodium channels in pain-related peripheral nerves. These channels are upregulated in various painful conditions, including neuropathic, inflammatory, cancer, and post-surgical pain. The tracer utilizes PET imaging—a well-established, widely available technology—to localize and quantify pain by targeting sodium channels that play a key role in pain signaling.

"Dosing our first human subject is a major step forward," said Dr. P. David Mozley, Chief Medical Officer at Lutroo Imaging (search)Search term. "Radiocaine (search)Search drug™ has the potential to transform how we detect and understand pain by allowing clinicians to see what's currently invisible."

Study Design and Objectives

The first-in-human Phase 1 clinical trial is being conducted under FDA IND clearance as a single-center, open-label study enrolling healthy volunteers. The trial's primary goals include:

• Safety evaluation
• Biodistribution analysis
• Radiation dosimetry profiling

Early preclinical data has shown promising results, including strong signal-to-noise ratios, high selectivity for pain-associated targets, target selectivity, favorable pharmacokinetics, and strong target-to-background signal.

Clinical and Research Applications

Beyond diagnostic applications, Radiocaine (search)Search drug™ is being positioned as a potential biomarker for use in drug development and clinical trials, helping researchers assess whether new pain therapies are actually working objectively and in real time. The findings from this initial study will inform future trials in pain disorders, such as lower back pain and neuropathic pain.

Market Positioning and Accessibility

Radiocaine (search)Search drug imaging utilizes PET, a well-established advanced imaging technology broadly available in clinical medicine. By leveraging PET's existing, widespread infrastructure, Radiocaine™ could be well-positioned for rapid clinical adoption and broad accessibility across hospitals, academic centers, and imaging networks.

The trial launch reflects a broader effort to bring precision diagnostics into pain medicine, moving beyond guesswork and trial-and-error prescribing. As the limitations of current treatment approaches become increasingly apparent, tools like Radiocaine (search)Search drug™ could offer a new path forward in pain management.