The photodynamic therapy that doctors are using to treat some cases of malignant mesothelioma got a boost Thursday when Pinnacle Biologics Inc. received the Orphan Drug Designation for its product PHOTOFRIN.
The Orphan Drug Designation, which is aimed at rare diseases that affect fewer than 200,000 people, provides a special FDA status for a drug, giving a manufacturer more encouragement to develop it, with tax credits and marketing incentives.
PHOTOFRIN (porfimer sodium) has shown signs of being more effective than some of the other drugs being used now in photodynamic therapy (PDT). It already has been used to treat small cell lung and esophageal cancers.
Mesothelioma is a rare cancer that is caused almost exclusively by an exposure to asbestos. It has been diagnosed in close to 3,000 people annually in the United States.
Photodynamic therapy often is used in conjunction with other treatments for mesothelioma that could include surgery and chemotherapy. It has been most effective in treating cancers that still are localized and yet to spread extensively.
The therapy begins with the injection of a photosensitizing drug that is allowed time to travel throughout the bloodstream, attaching itself more to cancer cells than the healthy cells. The second step includes delivering light with a specific wavelength that is designed to react with the photosensitive drug present in the cancer cells. The cells absorb the light and kill the blood vessels that are present in the cancerous tumor.
“I am pleased with the FDA decision granting Orphan Drug Designation,” said Patrick Ross, M.D., surgeon at Ohio State University Medical School who also is a consultant for Pinnacle. “PHOTOFRIN has shown tremendous value as a treatment modality in several forms of cancer, providing doctors now with innovative options to treat unmet medical needs such as mesothelioma.”
PHOTOFRIN wasn’t the only good news Thursday for mesothelioma patients. According to a study released in the American Journal of Respiratory and Critical Care Medicine, there have been promising new results with immune system based gene therapy.
University of Pennsylvania Clinical Trial
Researchers at the Perelman School of Medicine at the University of Pennsylvania are reporting that in a small clinical trial they found an immune-gene therapy that transfers just enough genetic material from an existing virus to trigger a patient’s own defenses to destroy cancer cells.
Researchers at Penn were using a modified cold virus to trigger a potent immune system stimulant (interferon-alpha) to boost the body’s ability to fight off viral infections and some cancers.
In the study, they used nine patients with malignant mesothelioma. The modified virus was injected directly into the chest cavity, where the tumor existed. Antibody responses directed against the tumors were observed in all cases. Although no helpful responses were seen in the four cases of advance disease, there was positive response, either disease stability or tumor regression, in the five remaining patients. No major side effects were seen.
“Given our encouraging results in this trial with advanced stage patients, we believe that multimodality regiments incorporating immune-gene therapy will have an important role in the treatment of earlier stage patients,” said Steven Albelda, the study’s senior author at Penn.
The modified virus was originally developed by Merck. The approach is now being tested in earlier-stage patients at Penn who also are receiving chemotherapy.