Illuminare Biotechnologies, a company focused on developing a nerve imaging agent to enhance surgical safety, announced first-in-human data results from a Phase 1 clinical trial evaluating Illuminare-1 (rizedisben) in robotic prostate cancer surgeries. The results have been published in JAMA Surgery.

Illuminare-1 is a novel small-molecule fluorophore that binds specifically to the nerve sheath substance, myelin, and fluoresces under blue light to enhance nerve visualization intraoperatively. It is designed to selectively illuminate nerves during surgery to improve delineation of nerves, thereby helping to avert unintended nerve injury.

“The publication of our Phase 1 results in JAMA Surgery, one of the world’s most respected medical journals, validates the potential of Illuminare-1 to address a significant unmet medical need in surgery,” said Walter Greenblatt, chairman of the board and CEO of Illuminare Biotechnologies. “This successful trial provides a clear road map for our upcoming Phase 2 studies, which are expected to commence in early 2026.”

The single-arm, open-label Phase 1 study was conducted at the world-renowned Memorial Sloan Kettering Cancer Center (MSK) in Manhattan between January 2023 and October 2024. The study enrolled 38 patients undergoing robot-assisted laparoscopic radical prostatectomy (RALP) to determine the optimal safe and clinically effective dose of Illuminare-1 for sustained and improved intraoperative visualization fluorescence of nerve structures. The obturator nerve was used as the reference nerve to measure fluorescence intensity.

“Seeing nerves clearly during surgery remains a major challenge,” said Timothy Donahue, M.D., urologic surgeon at MSK and principal investigator of the phase 1 study. “Further testing will show whether this technology can improve prostate cancer surgery — and possibly benefit other procedures too.”

The study findings suggest that a 3.0 mg/kg dose of Illuminare-1 was well tolerated and clinically effective for sustained fluorescence of nerve structures during RALP surgery. The concurrently published invited Commentary in JAMA Surgery (Atkinson & Sheu) highlighted that the trial represents a “pivotal step toward enhancing intraoperative nerve visualization.”

Key findings from the published results include:

• Improved nerve visualization: The probability of achieving moderate or better subjective fluorescence was highly correlated with an increased Illuminare-1 dose; in the expansion cohort with the effective dose, the small and typically difficult to observe, clinically relevant peri-prostatic neurovascular bundles that control erectile function demonstrated fluorescence in 8 of 9 (89%) patients at the effective dose
• Excellent safety profile: The study concluded that Illuminare-1 maintained a clean safety profile at all doses
• Dose-dependent efficacy: The proportion of patients who achieved sustained fluorescence of the obturator nerve increased with sequential dose escalation; sustained fluorescence was achieved in all patients at the effective dose
• Rapid onset of action: At the effective dose, nerves fluoresced within 15 minutes of IV injection
• Sustained fluorescence: At the effective dose, the obturator nerve showed sustained fluorescence for 90 minutes or longer, generally still fluorescing at wound closure

According to the Commentary authors, Illuminare-1 is novel because it directly binds to tissue, unlike other commonly used intraoperative dyes. They suggested that its application could extend to many other procedures, including inguinal hernia repairs, thyroidectomies, and axillary dissections.

The company plans to use the data from this trial to design subsequent studies to assess Illuminare-1’s ability to improve visualization and delineation of nerve structures and guide surgical resection while allowing for preservation of these nerves when appropriate.

MSK Disclosure: Memorial Sloan Kettering (MSK) has institutional financial interests related to Illuminare Biotechnologies.

About Illuminare Biotechnologies

Illuminare Biotechnologies is a clinical-stage company developing a proprietary, small-molecule, myelin-binding fluorophore named rizedisben (Illuminare-1) to provide real-time, intraoperative nerve visualization. The company’s goal is to minimize unintended nerve damage, improve patient outcomes, and expedite surgical procedures. Illuminare-1 has been granted FDA Fast Track Designation, a designation the FDA reserves for drugs deemed “to treat serious conditions and fill an unmet medical need.”

“Rizedisben in Minimally Invasive Surgery: A Nonrandomized Clinical Trial,” authored by Gold, S., Pere, M., Assel, M., et al., was published in JAMA Surgery on July 2, 2025.

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"The publication of our Phase 1 results in JAMA Surgery, one of the world’s most respected medical journals, validates the potential of Illuminare-1 to address a significant unmet medical need in surgery,” said Walter Greenblatt, CEO of Illuminare Bio