Light-activated drug offers relief for advanced esophageal cancer.

NEW YORK--(BUSINESS WIRE)--Oct. 1, 1996--Researchers at Columbia-Presbyterian Medical Center are offering a combination drug and laser treatment that greatly improves the quality of life for patients with advanced esophageal cancer.

Photodynamic therapy (PDT) uses a light-activated drug, Photofrin, in tandem with a low power medical laser to kill tumor cells. Currently FDA approved for treatment of advanced esophageal cancer, PDT offers promise for actually curing early stages of the disease.

Furthermore, various other cancers may respond well to this treatment. According to Charles J. Lightdale, M.D., Director of Clinical Gastroenterology and Professor of Clinical Medicine at Columbia-Presbyterian Medical Center, "This drug is taken up by most tumors. It's being looked at by thoracic surgeons, urologists, gynecologists, and neurosurgeons for possibly treating both advanced and early cancers. Any kind of neoplastic area that can be accessed with the laser light can potentially be treated." Esophageal cancer was among the first selected for photodynamic therapy, partly because the tumors are so accessible by passing an endoscope through the mouth.

Esophageal cancer is a very aggressive disease with a high mortality rate. The five-year survival rate is less than ten percent. Twelve thousand new cases are diagnosed in the U.S. each year, and it is responsible for 11,000 deaths annually.

In photodynamic therapy, the patient receives the drug Photofrin intravenously. The drug accumulates in greater concentration in abnormal tissue than in normal tissue. The blood vessels which feed abnormal tissue, such as tumors, contain higher than average concentrations of receptors for lipoproteins. These blood proteins carry the light-sensitive drug selectively to the targeted tissues. The endoscopist guides a medical laser down the patient's throat to the tumor site, then turns on the laser which activates the drug. This produces a toxic form of oxygen that destroys the abnormal tissue where the drug has accumulated and leaves normal tissues relatively unharmed.

"The goal is to provide comfort by opening the esophagus to allow patients to swallow better so they can eat," Dr. Lightdale explains. PDT is a significant improvement over traditional treatments for esophageal cancer. Burning the tumor away with a neodymium YAG laser is difficult and time-consuming for doctors and uncomfortable for patients. An alternative is to insert plastic or wire mesh tubes to hold the esophagus open. The wire mesh tubes, while easier to insert than plastic stents, can get plugged with food and can also migrate. The new photodynamic therapy is helpful with patients who, due to tumor shape or location, cannot benefit from either of those treatments. Photodynamic therapy's main side effect is sun sensitivity for four to six weeks after treatment, which most patients consider a small sacrifice compared to side effects from other therapies.

According to Dr. Lightdale, some patients whose cancers are caught early can be cured with photodynamic therapy. Cancer of the esophagus has tended to elude diagnosis until quite advanced -- the elastic nature of the esophagus permits a tumor to grow large before being felt.

But researchers have recently identified a precursor to esophageal cancer: Some people with chronic reflux disease (which causes stomach contents to back up into the esophagus) will develop Barrett's esophagus, a pre-malignant condition. "About half the esophageal cancer patients we see have adenocarcinoma of the esophagus, a type of glandular carcinoma -- we think nearly all of that is related to Barrett's. It seems to be an acquired condition associated with the constant bathing of that area with acid." Regular biopsies of Barrett's patients can detect esophageal cancer at an early, more treatable stage. Then, Dr. Lightdale explains, "Photodynamic therapy can remove all the abnormal Barrett's tissue. If you also use acid-suppressing drugs, then the healing that takes place is with the normal squamous lining. So you're not only getting rid of the early cancers, but you're getting rid of the Barrett's itself, theoretically taking away the risk of a recurrence." Another 50 percent of patients have squamous cell cancers, which are usually associated with heavy use of tobacco and alcohol. These tumors can be treated equally well with PDT.

"This terrible disease -- aside from being lethal -- makes patients very uncomfortable. The tumors block the esophagus, making it difficult to eat, and towards the end, even swallowing their own salivary secretions is difficult. The work here at Columbia-Presbyterian is mostly palliative treatment," Dr. Lightdale observes. "If we can relieve these patients' misery, that's important. Eating is more than getting nutrition -- there are social aspects. The patients want to eat with their families without choking, they want to participate in family gatherings; they don't want to be excluded."

"One patient had an incredible craving for a Big Mac. After he was treated, he called me from McDonald's -- it was very moving, we were both in tears. Being able to enjoy his favorite foods again made him more comfortable towards the end."

In late December 1995 the FDA granted approval for the light-activated drug Photofrin and associated laser and fiber optic-technology, strictly for use as a palliative treatment for advanced esophageal tumors. Photofrin is manufactured by QLT PhotoTherapeutics Inc., a biotechnology concern in Vancouver, Canada. There are about a dozen centers in the U.S. currently using photodynamic therapy.

CONTACT: Columbia Presbyterian Medical Center

Karin Eskenazi/Ruth Flaherty, 212/305-5587