While traditional cancer therapies have saved countless lives throughout decades, each one has exacted a cost in risks and side effects-some of which can be long-term and dangerous. Immunotherapy is a newer approach that utilizes molecularly targeted medicine to enhance a “weapon” found internally in patients: their own immune response
Patrick Soon-Shiong, MD, founder of NantWorks and the Chan Soon-Shiong Institute of Molecular Medicine, approaches cancer therapy with just such a transformative idea. “We must study a patient’s cancer at the genomic, proteomic, immunologic and metabolic level,” Soon-Shiong said. “This critical first step will transform cancer care from one that is based on trial-and-error treatment strategies that target the anatomy of the tumor to a precision medicine-based approach that routinely analyzes a patient’s cancer at the molecular level.”
He added that targeting a molecular profile with novel and more effective immunotherapies will harness the power of a patient’s own immune system and will “allow cancer to become a manageable chronic disease and provide patients with the promise of a long-term, high-quality life.”
Harnessing Killer Cells
Much of what Soon-Shiong advocates, including an understanding that cancer is not a single, tissue-specific disease, but rather a more complex group of “mutations, rearrangements and structural changes in the genome, changing dynamically over time,” has gained mainstream acceptance. However, his approach to cancer therapy-combining personalized information culled from next-generation molecular diagnostics with novel immunotherapies-is positioned at the very cutting edge of treatment.
“At our NantKwest clinical-stage immunotherapy company, we are harnessing the power of the human innate immune system, using natural killer cells to treat cancer, as well as infectious diseases and inflammatory diseases.” he explained. “These natural killer cells are a critical component of our immune system, representing the body’s first line of defense due to their innate ability to rapidly seek and destroy abnormal cells, such as cancer.
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“These natural killer cells are always turned on and can be used without prior activation, providing a distinct advantage over immunotherapy using T-cells [thymus cells],” Soon-Shiong said. Natural killer cell therapy is used to boost a patient’s own compromised immune system. Soon-Shiong calls it “. an off-the-shelf immunotherapy that is ready to be used in the heat of battle to supercharge a patient’s immune system and destroy cancer cells.“
Light and Immunotherapy
A seeming breakthrough in cancer therapy has recently appeared in the form of photoimmune therapy, a light-based approach that specifically damages and destroys a primary tumor while at the same time activating the immune system to clear away the remaining cancer cells.
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 has been 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 No. 1 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 reported in the Nov. 6, 2015, issue of Clinical Cancer Research. They added that the combination of immunotherapy offers “a feasible novel treatment strategy for advanced cancer.”
Soon-Shiong welcomes all such efforts to expand on the use and values of immunotherapy. He summed it up optimistically: “I believe this work will translate into significantly improved patient outcomes and will take us even further down the path to a cure for cancer.”
Valerie Neff Newitt is a staff writer. Contact: email@example.com