ASCO: On Target-Made Fluorescent Marker Boosts Ovarian Cancer Surgery Chances

Ovarian Cancer

A fluorescent marker tool developed by On Target Laboratories boosts the ability of surgeons to find and remove cancerous lesions during surgical procedures, increasing progression free and overall survival. 

On Target’s pafolacianine sodium injection is a targeted fluorescent marker being assessed in a Phase III study as an adjunct to visual inspection and palpation through intraoperative imaging of folate receptor positive ovarian cancer.

The study found that 33% of procedures that included pafolacianine sodium injection identified one or more additional lesions that had not been revealed through current imaging practices. The number increased in patients underwent interval debulking surgery. For those patients, the discovery of additional lesions was found in 39.7% of patients.

Following a presentation at the virtual American Society of Clinical Oncology meeting Monday, Dr. Janos L. Tanyi, an Assistant Professor of Obstetrics and Gynecology in the Perelman School of Medicine at the University of Pennsylvania and Principal Investigator of the trial, told BioSpace in an exclusive interview touted the benefits of the fluorescent dye in finding these additional lesions in ovarian cancer patients.

“With this fluorescent agent, we were able to identify the additional lesions in these patients. If we had not, that means the patients might have walked out with some hidden cancer after the surgery,” Tanyi said. “This will be a very good tool for surgeons to use to help these patients.”

If pafolacianine sodium injection is approved for use by a regulatory agency, Tanyi said there would be a short learning curve for surgeons to use the agent. But, once they have used it a few times, he predicted the benefits for patients would significantly increase.

Ovarian cancer is the fifth leading cancer-related cause of death among women. The American Cancer Society estimates that in 2021 about 21,410 women in the United States will receive a new diagnosis of ovarian cancer and about 13,770 women will die from the disease.

In March, the U.S. Food and Drug Administration accepted the New Drug Application for pafolacianine sodium injection under Priority Review. The NDA is based on positive data from Phase II and Phase III studies. 

Data from the Phase II study found surgeons were able to detect additional lesions, regardless of tissue location, in 48.3% of patients were published in Gynecologic Oncology. Data from that study also found that pafolacianine sodium injection demonstrated a sensitivity of 97% when controlling for detection correlation of multiple lesions within a single patient.

The Phase III 006 open-label study included patients with ovarian cancer who were scheduled to undergo cytoreductive surgery in order to remove as much cancerous tissue in the patient's abdomen as possible. The goal is to leave behind no tumor nodules that measure more than 1 centimeter in diameter. 

The fluorescent agent met the primary endpoint in a statistically significant percentage of patients whose folate receptor positive ovarian cancer lesion was detected by intraoperative fluorescence imaging on tissue not planned for resection and not detected by normal white light or palpation. 

Prior to the surgery, patients were infused with pafolacianine sodium injection to highlight folate receptors on the cancerous cells. Over 95% of ovarian cancers overexpress folate receptors to increase folate uptake for tumor growth. 

Special cameras using near-infrared light are then used to identify the agents in the abdominal cavity to help the surgeons remove the lesions. Tanyi said the agent’s highest concentration level in the cavity is about four hours after infusion but noted that it’s effective from about one hour after infusion up to 24 hours after. 

“This agent is a helpful tool in our hand to create a much better surgery,” he added. “It is a very big deal to be able to find additional lesions that would have been missed in one-third of patients.”

In addition to ovarian cancer, On Target is assessing pafolacianine sodium injection in the ongoing Phase III ELUCIDATE Trial in lung cancer. 

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