‘Seek and destroy’ cancer trial explores nonsurgical therapies

Called a “seek and destroy” alternative therapy option, the treatment combines light-activated nanoparticles called porphysomes with photodynamic therapy (PDT). While PDT (i.e. use of laser light to destroy tumors) is not a novel therapy, the trial marks the first pairing of it with a new nanoparticle technology, which was developed by Gang Zheng, PhD, a researcher at the University Health Network (UHN) in Toronto, the University of Guelph reports.

The technique might, ultimately, offer a targeted, nonsurgical way to diagnose and treat tumors in pets and humans, which could prevent over-treatment and reduce common side effects, says Michelle Oblak, DVM, DVSc, DACVS, a veterinary surgeon oncologist and professor in OVC’s department of clinical studies.

“This is such an exciting opportunity to have an impact on how cancer is treated in both humans and pets, and to be involved in such an incredibly innovative idea and invention,” she says.

“It’s motivating for us to continue the work we’re doing. This could change the way we treat and diagnose cancer in the future.”

The clinical trial kicked off in February with a 10-year-old beagle named Shiloh. Per the trial, which aims to recruit a total of 10 canine patients, porphysomes are injected into the bloodstream. The nanoparticles then collect in the tumor or any spot where cancer may have spread.

The light-activated molecule’s fluorescent glow allows researchers to track its location using a special light source, U of G reports. Additionally, the porphysomes make the tissue more vulnerable to damage from laser light. A beam of near-infrared laser light directed through a nanofiber activates the porphysome, which then destroys cancerous tissue.

For the clinical trial, the research team is destroying only a portion of the tumor, then taking samples of it and the lymph nodes to assess results of the therapy. (Patients in the trial will undergo standard-of-care surgery to remove the entire tumor, U of G reports.)

“There’s a lot of interest in this as a nonsurgical option,” Dr. Oblak says. “This could really revolutionize many different aspects of cancer treatment and diagnosis.”

With the trial, researchers hope to refine the treatment for use in animals and, ultimately, determine its use for treating various types of human cancer as an adjunct or alternative to surgery.

“This is a great model to understand how porphysomes and PDT work,” says Charly McKenna, research manager for OVC’s veterinary clinical trials and the Veterinary Medical Innovation Program.

Written with files from the University of Guelph.