May 7, 2006 /source: McGill University, Montreal, Ca./ 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. Doctors shine the laser into the body through a catheter, targeting the tumor using fiber 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. www.muhc.ca
Studies of a vascular-acting photosensitizer, Pd-bacteriopheophorbide (Tookad), in normal canine prostate and spontaneous canine prostate cancer. Huang z, et al.
HealthONE Alliance, Denver, Colorado 80203, USA. Lasers Surg Med. 2005 Jun;36(5):390-7. "RESULTS: Tookad is a vascular-acting drug and clears rapidly from the circulation. Tookad-PDT-induced lesions, in both normal and cancerous prostates, were characterized by marked hemorrhagic necrosis. CONCLUSIONS: Tookad-PDT is very effective in ablating prostatic tissue through its vascular effects."
Effects of photodynamic therapy on peripheral nerve: in situ compound-action potentials study in a canine model. Dole KC et al.
HealthONE, Denver, Colorado 80203, USA;
Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 3 NEGMA-LERADS, Toussus-Le-Noble, France. "This canine model adequately demonstrates effects of Tookad PDT on peripheral nerves. Treatment with Tookad alone, light alone, or low-dose PDT (i.e., 50 J/cm 2 ) produces very little or no change in nerve conduction properties. Direct irradiation of the saphenous nerve with 100-200 J/cm 2 light at 1-2 mg/kg drug dose can induce nerve damage and affect nerve conduction. Since these dose levels are likely used for prostate cancer patients, in order to preserve prostate nerve and minimize adverse effect on sexual and urinary functions in the process of total ablation of prostate cancer, possible side effects of interstitial PDT on pelvic plexus need to be further investigated. " Full free text online. Author Manuscript, 2005.
Prostate cancer drug may kill other tumours
From the Toronto Star,
2005-06-13
SCOTT ROBERTS, staff reporter. Posted, PSA Rising forums 28 Jul 2005
British Journal of Cancer (2003) 89, 2320-2326.
Selectivity of the photosensitiser Tookad for photodynamic therapy evaluated in the Syrian golden hamster cheek pouch tumour modelF Borle, et al. Institute of Environmental Engineering, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland....
Photochemistry and Photobiology: Vol. 78, No. 2, pp. 124-130.
Endobronchial Phototoxicity of WST 09 (Tookad®), a New Fast-Acting Photosensitizer for Photodynamic Therapy: Preclinical Study in the Pig
Alain Tremblay, et al.
Divisions of Respiratory Medicine and Medical Oncology, University of Calgary, Calgary, Alberta, Canada ....
BOLD contrast MR monitors antivascular photodynamic therapy in lab mice. By Don Rauf. DiagnosticImaging.com, March 2004
Free full text .pdf to download:
Photodynamic Therapy of Established Prostatic Adenocarcinoma with TOOKAD: A Biphasic Apparent Diffusion Coefficient Change as Potential Early MRI Response Marker Authors: Plaks V. ; Koudinova N. ; Nevo U. ; Pinthus J.H. ; Kanety H. ; Eshhar Z.; Ramon J. ; Scherz A. 7 ; Neeman M. ; Salomon Y. Source: Neoplasia , Volume 6, Number 3, May/June 2004, pp. 224-233(10)
Other types of photodynamic therapy for cancer
Europe: biolitec pharma's Foscan®
Foscan® is a photosensitizing agent (a light-sensitive drug), which contains temoporfin and is used in photodynamic therapy (PDT).
In October 2001, Foscan® was approved in the European Union, Norway & Iceland as a local therapy for the palliative treatment of patients with advanced head and neck cancer who have failed prior therapies and are unsuitable for radiotherapy, surgery or systemic chemotherapy. More at biolitecpharma.com
USA & Canada
In the USA to date, the Food and Drug Administration (FDA) has approved the photosensitizing agent called porfimer sodium , or Photofrin®, for use in PDT to treat or relieve the symptoms of esophageal cancer and non-small cell lung cancer (7). Porfimer sodium is approved to relieve symptoms of esophageal cancer when the cancer obstructs the esophagus or when the cancer cannot be satisfactorily treated with laser therapy alone. Porfimer sodium is used to treat non-small cell lung cancer in patients for whom the usual treatments are not appropriate, and to relieve symptoms in patients with non-small cell lung cancer that obstructs the airways. In 2003, the FDA approved porfimer sodium for the treatment of precancerous lesions in patients with Barrett's esophagus (a condition that can lead to esophageal cancer).
Photodynamic Therapy for Cancer: Questions and Answers (National Cancer Institute)
Axcan Pharma INc. Photofrin:
Photodynamic Therapy for non-small cell lung cancer
Photofrin PDT Reduces Esophageal Cancer Occurrence in Patients With Barrett's High Grade Dysplasia - Results of a 5-Year Follow-up Study September 13, 2005
Axcan Receives Food and Drug Administration Approval for Photofrin, for the Ablation of High-Grade Dysplasia in Barrett's Esophagus Patients August 4, 2003
This page made and last edited by J. Strax, May 7, 2006
