UTRECHT, The Netherlands, November 20, 2015 /PRNewswire/ --
A breakthrough in cancer therapy has recently appeared in the form of photoimmune therapy, a light-based approach that specifically damages and destroys the primary tumor while at the same time activating the immune system to clear away the remaining cancer cells.
(Photo: http://photos.prnewswire.com/prnh/20151120/289679-INFO )
This approach combines two established therapies: photodynamic therapy (PDT) and immunotherapy. PDT entails the use of a light-sensitizing agent, or photosensitizer, along with oxygen and light, to trigger reactions that selectively destroy cancer cells and render those cells more vulnerable to the immune system. Immunotherapy actually includes a number of strategies aimed at further exploiting various parts and mechanisms of the immune system.
The value of the photoimmune approach is demonstrated in a landmark study conducted at Leiden University Medical Center (LUMC) in the Netherlands. The photosensitizing agent used in this study was Bremachlorin-PDT, a non-toxic, chlorophyll-derived agent that captures and then transmits light energy for therapeutic purposes. The immunotherapy strategy they chose focused on a peptide-based vaccine that specifically activates the T-cell system against cancer.
The Leiden study focused on tumor models of two kinds: aggressive lymphoma and aggressive cervical cancer. The study found that Bremachlorin-PDT by itself resulted in a significant slowing of tumor growth in all the test subjects. When PDT was combined with a peptide-based vaccine strategy, one third of the animals were completely cured of cancer, meaning that the disease totally disappeared.
All of the cured test subjects in the study were fully protected against the subsequent development of the same type of cancer. Moreover, the combination treatment of primary tumors led to the eradication of distant secondary tumors, or metastases. Metastatic disease is the number one cause of cancer-related death.
The researchers concluded that Bremachlorin-PDT, together with the long peptide vaccine strategy, produced a potent whole-body immune response against these aggressive cancers. “We show that immunotherapy can be efficiently combined with PDT to eradicate established tumors, based on strong local tumor destruction and the induction of a robust systemic immune response,” the Leiden group reports online ahead-of-print in the 6 November 2015 issue of the medical journal, Clinical Cancer Research. They add that the combination of immunotherapy with offers “a feasible novel treatment strategy for advanced cancer.”
Since 2009, Bremachlorin® has been approved for clinical use in Russia (under the name Radachlorin®) and has conditional approval in South Korea. Preclinical studies are under way in the Netherlands with a goal toward achieving clinical acceptance in the European Union. The Leiden study was spearheaded by Dr. Ferry Ossendorp and Jan Willem Kleinovink of the Department of Immunohematology and Blood Transfusion at Leiden University Medical Center in the Netherlands.
SOURCE Photoimmune Discoveries
