Early trials of an experimental photosensitizer cancer drug called Tookad have yielded dramatic results, according to Dr. Mostafa Elhilali, Chief Surgeon at the McGill University Health Centre (MUHC) and study principal investigator. In a recently completed trial, 46 percent of patients showed no evidence of prostate cancer after treatment with optimum doses of Tookad and the correct light intensity. A larger study to determine the drug's efficacy is now underway at the MUHC.
"This new trial is designed to treat patients whose prostate cancers have recurred despite radiation therapy," explains Dr. Elhilali. "From previous studies, we have learned optimum light intensity and drug dosages. Now, we plan to treat patients, using this information to deliver optimum therapy to all participants. If the trial also shows beneficial effects, we will go to the next phase — registering the drug to make it generally available for therapy."
"Results so far are unprecedented," adds Dr. Armen Aprikian, Chief of Urology at MUHC and study co-investigator. "However, they are not conclusive. The upcoming trial is so important because it will give us definitive evidence of how effective Tookad therapy is. Good results will lead to wider use."
Tookad (from a Hebrew word meaning the warmth of light) is a non-toxic, light-activated drug derived from chlorophyll. Injected into the patient, it remains inactive until exposed to laser light, which is shone into the target tumour using fibre optics. Once activated, Tookad produces a chemical that blocks blood vessels in the immediate area and chokes off the tumour's blood supply.
"The mechanism is local, not systemic," explains Dr. Elhilali. "The drug is activated only where light is shining, so nearby healthy tissue is spared. Tookad has another advantage: it is eliminated in two hours. Previously, we had to keep people in the dark for weeks after treatment with these types of agents."
MUHC researchers are now recruiting patients with recurring prostate cancer to participate in phase two trials with Tookad. Candidates should contact Dr. Elhilali or Dr. Aprikian at the MUHC to learn more, or call Joanne Savard at 934-1934, extension 34037.
Current Canadian studies of Tookad in recurrent prostate cancer patients are the first of their kind anywhere. "This is totally new," says Dr. Aprikian. "It's appropriate that the MUHC, as an internationally recognized institution, is leading the way in this area."
The McGill University Health Centre (MUHC) is a comprehensive academic health institution with an international reputation for excellence in clinical programs, research and teaching. The MUHC is a merger of five teaching hospitals affiliated with the Faculty of Medicine at McGill University — the Montreal Children's, Montreal General, Royal Victoria, and Montreal Neurological Hospitals, as well as the Montreal Chest Institute. Building on the tradition of medical leadership of the founding hospitals, the goal of the MUHC is to provide patient care based on the most advanced knowledge in the health care field, and to contribute to the development of new knowledge. MUHC website