Illuminating cancer surgery with a dye that makes tumors glow

By using a fluorescent dye that binds to cancer cells and makes them glow during surgery, researchers believe they can help make sure every piece of a person’s tumor has been removed.

First discovered at Purdue University and being developed by On Target Laboratories, the molecular markers attach themselves to the surface of lung and ovarian cancer cells and illuminate when viewed through an endoscope equipped with a near-infrared camera. 

Now, researchers have launched phase 3 trials of the intravenous dye, dubbed OTL38, in lung and ovarian cancers with a boost from previous FDA fast-track and orphan designations.

An earlier phase 2 study of the dye showed improvements in the localization of small, peripheral and difficult-to-find lesions in patients with non-small cell lung cancer and also helped surgeons better establish the microscopic margins of confirmed nodules. Altogether, fluorescence-guided surgery improved the outcomes for 26% of patients undergoing a pulmonary resection. 

"OTL38 is the first technique that is specific to imaging adenocarcinomas of the lung, which is one of the most common types of invasive lung cancer, making it unique and clinically useful in this respect," said Inderpal Sarkaria, a thoracic surgeon at the University of Pittsburgh Medical Center (UPMC) who participated in the phase 2 study, which was recently presented at the annual meeting of the Society of Thoracic Surgeons in New Orleans.

The fluorescent markers help surgeons
spot and remove cancer cells during surgery.
(Photo by On Target Laboratories)

Surgical resection is the recommended course of action for early-stage lung tumors, but a large percentage of patients still see a recurrence of their cancer after it grows back from undetected clusters of cells leftover from the procedure.

"Localization of tumors, identification of occult tumors, and immediate tumor margin assessment during surgery for adenocarcinomas of the lung were significantly improved with the use of this technology,” said Sarkaria, who also serves as vice chairman for clinical affairs, director of thoracic robotic surgery and co-director of UPMC’s Esophageal Surgery Institute.

A separate phase 2 study in ovarian cancer also demonstrated the ability to help surgeons detect additional hidden lesions—including at least one in 48% of participants and four or more in 40% of those with miliary disease, who typically have a poorer prognosis. 

"OTL38 is the first of a portfolio of imaging agents designed to give surgeons the real-time capability to detect malignant tissue in multiple cancer types," said On Target CEO Chris Barys.