Researchers at the Ireland Cancer Center at University Hospitals of Cleveland (UHC) and Case Western Reserve University School of Medicine are, for the first time in human clinical trials, using a new drug designed to sensitize cancer cells for destruction.

The drug, called Pc 4, was developed in laboratories at CWRU and UHC.

The drug represents a breakthrough in the process of photodynamic therapy (PDT), where laser light is used in combination with a light-sensitive drug to break down and destroy cancerous tissue.

Currently, there is only one drug called Photofrin approved by the federal government for this use. Photofrin, however, causes patients' skin to be excessively sensitive to natural and artificial light of any kind, so that patients must literally live in the dark, unable to go outside into direct sunlight, for weeks after treatment.

The new drug, Pc 4, a phthalocyanine compound, targets cancerous cells preferentially, leaving healthy tissue alone. When laser light is directed to the patient's skin, it activates the Pc4 that has infiltrated the cancerous tissue. In combination, the light and the drug destroy cancer cells.

Led by Nancy Oleinick, director of radiation biology at the Ireland Cancer Center, and professor of radiation oncology at CWRU, the research team spent nearly a decade developing Pc 4.

"This innovative therapy promises to be a significant advance in cancer treatment," said Timothy Kinsella, a member of the team and director of radiation oncology at the Ireland Cancer Center and chairman of the department of radiation oncology at UHC and CWRU. "If the trials are successful, PDT with Pc 4 will eventually join surgery, radiation and chemotherapy as part of the arsenal against cancer."

As a photosensitizing drug, Pc 4 prepares cancerous tissue to be broken down by light and oxygen. A small amount of the drug is administered intravenously to the patient over a two-hour period. About 24 hours later, a red laser light is applied, which is absorbed by the tumor-localized Pc 4. The light-activated photosensitizing compound produces forms of oxygen that kill cancer cells and break down the tumor while leaving surrounding normal cells virtually untouched.

The study will focus on cutaneous (skin) lesions metastasized from various cancers such as breast, lymphoma, head and neck and non-melanoma skin cancers.

In this Phase I trial, researchers will try to determine the maximum dose of the drug that can be tolerated by the patient and toxic side effects related to dosage. They also will determine which dose is best for treating cancer.

For more information, call the Ireland Cancer Center's Information Service at 1-800-641-2422.