ALERT---FDA Panel Approval-----News Release.........
Dow Jones Newswires -- September 18, 1997
FDA Panel Backs Widened Use Of QLT's Photofrin
By Anita Womack
BETHESDA, Md. (Dow Jones)--A Food and Drug Administration panel has
recommended expanded approval of QLT PhotoTherapeutics Inc.'s (QLTIF)
drug Photofrin for treating some lung cancer patients.
However, members of the Oncologic Drugs Advisory Committee voted
against using the drug in treating palliation, which removes symptoms of late stage cancer patients without trying to cure them of disease. Panel members resoundingly said there was too much missing data to approve this indication. Panel members also rejected use of the drug in treating in situ cases, very rare, very early stages of cancer. Some panel members said the company did not present data to prove the in situ patients actually had cancer.
Nearly every member of the FDA's independent panel said the data presented by the company was flawed.
"We have lots of opportunity for bias," said Dr. Richard M. Simon, chief of the Biometric Research Branch of the National Cancer Institute. "On the otherhand, we have objective response data. Photdynamic therapy is at least as effective as the YAG laser at the one month time frame."
Meanwhile, Dr. Richard L. Schilsky, director of the University of Chicago Cancer Research Center said in his mind "this is an elegant technique. It makes sense that if you open up obstruction that patients should be improved. I'm prepared to accept that that is the case - I just don't know if that happens 50% of the time, 30% of the time or 15% of the time."
Several panel members pointed out that it would be difficult if not impossible to do randomized trials with the targeted group.
Senior panel members were leaning toward voting that the trials were not adequate and well controlled but voting to recommend approval for reduction of obstruction and palliation of symptoms in patients with completely or partially obstructing endobronchial non-small cell lung cancer. But FDA official Robert Temple told panel members that it was legally impossible for the FDA to approve a drug that the panel did not feel had adequate and well controlled trials.
The FDA is not bound by the panel's decision, but generally follows its lead.
Photodynamic therapy selectively kills or alters disease-causing ells while sparing healthy ones. Treatment is a two-step process. The photosensitive drug is first administered intravenously to the patient. Then it is followed by an interval during which the drug circulates and accumulates in abnormal tissue while largely clearing from surrounding normal tissue.
The drug has no apparent effect on the abnormal tissue on its own. However when it is concentrated in the cells and the target area is exposd to a pre-calculated dose of light during the treatment procedure, the accumulated drug reacts with oxygen contained within the tissue to form a short-lived highly-active form of oxygen. This brings about oxidative reactions within the cell, resulting in cell destruction and an inflammatory response.
Analyst Christine Charette of Nesbitt Burns of Toronto said QLT currently has 10% penetration of the esophageal cancer market. There are an estimated 11,000 esophageal cancer patients in the U.S., with about half of them eligible for treatment. Charette said the company has been making about $1 million a quarter for Photofrin in the U.S. The drug has only been on the market since October.
Charette added that the recommendation the company sought for microinvasive tumors, tumors of limited depths, was about 20% of the
180,000 population. That translates to an additional patient population of 36,000 patients who will use at least one application at a cost of $4,200, she said. It is not certain if the FDA and the company will further discuss the tumor size and possibly depth that would be applicable to the recommendation.
However, Charette added that there are several other heavy hitting studies involving a treatment for Barrett's Esophagus, a pre-cancerous condition affecting about one million people in the U.S. each year. QLT also is investigating a therapy to treat age-related macular degeneration, a leading cause of blindness in the elderly for which there is no treatment for 80% of the population.
"This is a landmark decision," said Dr. Mohammad Azab, vice president of clinical research and medical affairs at QLT PhotoTherapeutics Inc. "This is the first time photodynamic therapy has been approved for a curative intent in the United States."
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