By Mary Welch

The FDA approved a third indication - the palliative treatment of late-stage lung cancer - for Photofrin, a light-activated drug developed by QLT PhotoTherapeutics Inc.

Photofrin (porfimer sodium) was given the agency's nod for the reduction of obstruction and palliation of symptoms in patients with completely or partially obstructing endobronchial non-small-cell lung cancer.

"It's an important indication," said Harvey Pass, professor of surgery and oncology at the Karmanos Cancer Institute of Wayne State University, in Detroit. Pass presented data to the FDA as part of the approval process.

"Photofrin is more targeted to oncological uses than just laser therapy," he said. "For reasons not entirely worked out, it is retained by the cancer tissue and released by normal tissues. It has a longer effect, and it works quickly."

In 1995, QLT earned FDA approval for Photofrin as a palliative treatment for certain patients with esophageal cancer.

In January, Photofrin was approved as a potentially curative treatment for early-stage micro-invasive lung cancer in patients who are not candidates for surgery or radiotherapy. The FDA's Oncologic Drugs Advisory Committee had unanimously recommended approval, in September 1997, of Photofrin as an early-stage lung cancer treatment, but failed to vote on the drug as a palliative for late-stage lung cancer.

A year later, it voted to recommend approval in that indication, and the FDA followed the panel's advice in its most recent action. (See BioWorld Today, Sept. 8, 1998 p. 1.)

Photofrin is administered intravenously, and drug molecules go through the bloodstream, collecting in and around the tumor cells. When activated by the nonthermal light from a laser, it produces toxic oxygen compounds, which disintegrate the tumor cells. Necrotic tissue and exudate are subsequently removed later through a bronchoscope.

Principal side effects include skin sensitivity to light for about 30 days (which occurs in all patients), and about 10 percent of all patients experience inflammation at the treatment site, causing varying degrees of shortness of breath or coughing.

The FDA's most recent decision allows QLT's partner, Sanofi Pharmaceuticals Inc., of New York, the U.S. subsidiary of Paris-based Sanofi SA, to broaden its current marketing efforts. A U.S. commercial launch is expected in the first quarter of next year.

More than 171,500 Americans will be diagnosed with lung cancer this year at a fairly late stage in the progression of this deadly disease, Pass said.

"A significant number of these lung cancer patients will eventually suffer bronchial obstruction and hemorrhaging as the disease progresses, and photodynamic therapy with Photofrin offers patients and oncologists alike an effective alternative palliative treatment," he said.

In studies involving more than 200 patients, Photofrin reduced obstruction of the airways caused by a tumor in 50 percent of the patients. Clinically significant relief of at least one of the associated disease symptoms - such as shortness of breath, cough or tumor bleeding - was experienced by 40 percent of the patients.

Photofrin is currently in Phase III trials to treat Barrett's esophagus syndrome. The company anticipates filing with the FDA to market Photofrin for that indication in 2000.

QLT's stock (NASDAQ:QLTIF) closed Monday at $26, up $3.937. *