UCSF researchers led the first-in-human study of a novel near-infrared fluorescence imaging agent that targets prostate-specific membrane antigen (PSMA). They found that the agent, IS-002, has the potential to intraoperatively detect prostate cancer that cannot be identified using standard white light imaging.

“We are hopeful that intraoperative PSMA imaging can allow for more complete cancer excision and reduced morbidity,” said UCSF urologic cancer surgeon Peter Carroll, MD, MPH, who led the study.

Lighting up hidden cancer

IS-002 specifically targets the PSMA receptor and holds promise for improving prostatectomy outcomes. In this phase 1 single-center study, the researchers tested IS-002 fluorescence imaging for the first time in 24 patients with high-risk prostate cancer undergoing robotic-assisted radical prostatectomy with pelvic lymph node dissection. They found that IS-002 is safe, clears from the body quickly, and potentially allows for real-time intraoperative visualization of prostate cancer that can’t be identified by conventional white light imaging.

By using IS-002 fluorescence imaging, surgeons located disease in 12 patients that might have otherwise gone undetected. They found and removed locoregional or residual disease (or both) in the prostate resection bed in seven patients and identified and excised metastatic lymph nodes in five patients.

“This phase 1 study showed that IS-002 is nontoxic, well-tolerated, and lights up prostate cancer that is not identified by white light,” Carroll said. A multisite, randomized phase 2 trial is underway, led at UCSF by Carroll and urologic cancer surgeon Hao Nguyen, MD, PhD, principal investigator.

At the forefront of PSMA-targeted imaging

Carroll and UCSF radiologist Thomas Hope, MD, were integral to the research that led to the Food and Drug Administration’s approval of PSMA PET, which enables precise cancer staging and personalized treatment. “PSMA PET has been a game changer because it’s a much more sensitive imaging test than other methods,” Carroll said. “It’s given us tremendous anatomical insight into where this disease may exist that we didn’t previously have.”

Carroll, Hope and other researchers recently published the results of a multicenter study that found PSMA PET improved presurgical biochemical recurrence risk assessment in patients with intermediate- and high-risk prostate cancer who were treated with radical prostatectomy and pelvic lymph node dissection. 

Building on that breakthrough, the new study leverages PSMA-targeted imaging in the intraoperative setting. “We’re using advanced technology to better identify disease in real time and manage the patient’s cancer based on the imaging,” Carroll said. “The fluorescent camera is built into the robot, so this technology can be rapidly deployed.”

According to Carroll, patients with high-risk prostate cancer have a recurrence rate of 30 to 40%. “These patients are most likely to benefit from this new imaging technology,” he said.

Cancer research and treatment take place within the UCSF Helen Diller Family Comprehensive Cancer Center.

 

To learn more

UCSF Prostate Cancer Center
Medical oncology
Phone: (415) 476-4616 | Fax: (415) 353-7107
Surgical oncology
Phone: (415) 353-7171 | Fax: (415) 514-6195
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