Laser therapy offers new hope for inoperable pancreatic tumors

UCI Health, the clinical enterprise of the University of California, Irvine, is conducting a first-in-human, phase 1 clinical trial using laser light to target localized but inoperable pancreatic tumors to help patients become cancer free.

The UCI Health Chao Family Comprehensive Cancer Center is one of only two U.S. cancer centers testing the potential breakthrough treatment using vascular targeted photodynamic therapy (VTP), which was developed by the Israel-based biotechnology company, ImPact Biotech.

"We use the light-sensitive drug padeliporfin to destroy pancreatic tumors encasing major arteries in the abdomen – once the vessels are clear of tumors, patients can undergo what can be a lifesaving surgery," said UCI Health radiologist Dr. Nadine Abi-Jaoudeh, a nationally recognized expert in interventional approaches to treating cancers and lead investigator of the groundbreaking clinical trial.

In preliminary results published in the Journal of Vascular and Interventional Radiology, Abi-Jaoudeh reported on three trial participants treated with the padeliporfin VTP therapy. Since then, another three patients have received the targeted low-light therapy. Of the six total patients, four had the remaining tumor tissue surgically removed. Three of those patients had no evidence of cancer cells at the surgical margins.

"This is a significant finding because patients with localized cancers who cannot undergo surgery have similarly low survival rates as patients with metastasized pancreatic cancer," says Abi-Jaoudeh, who is also a professor of radiology at the UC Irvine School of Medicine.

Co-investigators include UCI Health medical oncologist Dr. Jennifer B. Valerin and surgeons Dr. David K. Imagawa and Dr. Zeljka Jutric.

Why focus on pancreatic tumors?

Pancreatic cancer has one of the lowest survival rates of all cancers. One reason is that for the 50% of patients with localized cancer (meaning that it hasn't spread), two-thirds of them are not candidates for surgery. This is usually because their tumors wrap around major arteries that deliver blood to the abdomen, and surgery would risk damaging the vessels.

How is the treatment delivered?

First, the clinical team injects the patient with the light-sensitive drug. Next, they insert a balloon into the tumor-encased blood vessel. Inside the balloon is a laser. When it is turned on, it activates the drug, killing the tumor surrounding the vessel. As part of the phase 1 trial, the clinical research team is testing three incremental doses of laser illumination to determine the most effective one.

VTP treatment is delivered in two increments of five minutes each after participants have been injected with the drug padeliporfin.

How does the treatment destroy tumors?

Illuminating the padeliporfin causes a photochemical reaction within the blood vessel that breaks down the tumor's network of blood vessels and ultimately, the tumor itself.

Although tissue destruction begins immediately after treatment, the team waits two weeks before surgically removing the residual tumor tissue.

Can patients be exposed to light after treatment?

No, patients must spend three days in a dark room because exposure to light could cause damage to other areas of the body, including the skin. That's why this therapy hasn't been used to treat larger areas.

If preliminary clinical trial results remain positive, what's next?

If the investigative team confirms that this approach is effective, the hope is to move on to the next phases of the trial. Phases 2 and 3, once approved by the U.S. Food and Drug Administration, will test VTP therapy in significantly more patients.